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Gavin, John. "Subpixel image analysis." Thesis, University of Bath, 1995. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307131.
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Brady, Michael Richard. "Subpixel Resolution Schemes for Multiphase Flows." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/36104.
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This effort explores novel sub-resolution particle center estimation algorithms for Digital Particle Tracking Velocimetry (DPIV). The errors of these new methods were classified through Monte-Carlo simulations. These schemes provide direct measurements of the apparent particle image diameter and the subpixel position. The new methods significantly reduce the bias error due to pixel discretization, thus reducing the total error in the position and sizing measurement compared to the classic three point and least squares Gaussian estimators. In addition, the accuracy of the least-squares fits were essentially independent of the true particle diameter and significantly reduced the particle position error compared with current estimation schemes. The results of the Monte Carlo simulations were validated in a high pressure spray atomization experiment.<br>Master of Science
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Karu, Zoher Z. 1968. "Fast subpixel registration of 3-D images." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10205.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.<br>Includes bibliographical references (p. 165-174).<br>by Zoher Zain Karu.<br>Ph.D.
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Lotspeich, James T. "Tracking Subpixel Targets with Critically Sampled Optical Sensors." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/17407.
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Approved for public release; distribution is unlimited<br>In many remote sensing applications, the area of a scene sensed by a single pixel can often be measured in square meters. This means that many objects of interest in a scene are smaller than a single pixel in the resulting image. Current tracking methods rely on robust object detection using multi-pixel features. A subpixel object does not provide enough information for these methods to work. This dissertation presents a method for tracking subpixel objects in image sequences captured from a stationary sensor that is critically sampled spatially. Using template matching, we estimate the maximum a posteriori probability of the target state over a sequence of images. A distance transform is used to calculate the motion prior in linear time, dramatically decreasing computation requirements. We compare the results of this method to a previously state-of-the-art track-before-detect particle filter designed for tracking small, low contrast objects using both synthetic and real-world imagery. Results show our method produces more accurate state estimates and higher detection rates than the current state of the art methods at signal-to-noise ratios as low as 3dB.
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Timoner, Samson J. (Samson Joshua) 1975. "Subpixel motion estimation from sequences of video images." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/86429.
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Antunes, Filho Amauri. "Restauração de imagens com precisão subpixel utilizando restrições convexas." Universidade Federal de São Carlos, 2016. https://repositorio.ufscar.br/handle/ufscar/8804.
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Previous issue date: 2016-12-09<br>Não recebi financiamento<br>The super-resolution aims to obtain a higher resolution image, using information from one or more low resolution images. There are different applications where super-resolution may be used, such as medical and forensic images. This work proposes a study and development of algorithms, based on Tekalp and Sezan’s algorithm, using the projection onto convex sets theory, in order to obtain super-resolution, therefore obtaining a higher resolution image, from a low resolution images set, with subpixel informations. We proposed the adition of a convex restriction based on Richardon-Lucy’s algorithm, modified to be weighted by Canny’s filter, along with total variation regularization, aiming to restore frequencies lost during high resolution images decimation and degradation processes . Therefore, we have a hybrid approach, that implements spatial and spectral super-resolution simultaneously, based on projection onto convex sets. The obtained results by the proposed algorithms were compared to Tekalp and Sezan’s base algorithm. The visual analysis of the images, along with the mean square error were taken in consideration for comparisons. In development, grayscale images were used, but the methods are extensible for color images. Results showed improvement in the obtained images, with less noise, blurring and more edge definition than the low resolution images. We conclude that the approach has potential for medical applications and forensic computation.<br>A super-resolução tem por objetivo a obtenção de uma imagem de maior resolução, utilizando informações de uma ou mais imagens de baixa resolução. Existem diferentes aplicações onde a utilização da super-resolução é empregada, como imagens médicas e forenses. A proposta deste trabalho é o estudo e desenvolvimento de algoritmos, baseados no algoritmo de Tekalp e Sezan, que utilizam a teoria de projeções sobre conjuntos convexos com o objetivo de super-resolução, obtendo uma imagem de maior resolução a partir de um conjunto de imagens com informações subpixel. Propomos também, uma restrição convexa baseada no algoritmo de Richardson-Lucy, modificado para ser ponderado pelo filtro de Canny, juntamente com regularização total variation, com o intuito de restaurar frequências perdidas durante os processos de decimação e degradação das imagens de alta resolução. Com isso temos uma abordagem híbrida, que implementa super-resolução espacial e espectral simultaneamente, baseada em projeções sobre conjuntos convexos. Os resultados obtidos pelos algoritmos propostos foram comparados com o algoritmo base de Tekalp e Sezan. Para as comparações, levou-se em consideração a análise visual das imagens juntamente com o erro quadrático médio. No desenvolvimento, foram utilizadas imagens em tons de cinza, mas os métodos são extensíveis para imagens coloridas. Os resultados apresentaram melhoria nas imagens obtidas em relação as imagens de baixa resolução, minimizando o ruído, o borramento e melhor definição das bordas. Concluímos que a abordagem possui potencial para aplicações médicas e em computação forense.
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Wisniewski, Wit Tadeusz. "Subpixel Image Co-Registration Using a Novel Divergence Measure." Diss., Tucson, Arizona : University of Arizona, 2006. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1529%5F1%5Fm.pdf&type=application/pdf.
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Broadwater, Joshua B. "Physics-based detection of subpixel targets in hyperspectral imagery." College Park, Md. : University of Maryland, 2007. http://hdl.handle.net/1903/6820.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2007.<br>Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Tabbone, Salvatore-Antoine. "Détection multi-échelle de contours subpixel et de jonctions." Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL021N.
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Un système de vision se décompose généralement en plusieurs niveaux. Le premier niveau (bas niveau) a pour objectif d'extraire, de l'énorme quantité d'information contenue dans une image, des primitives robustes et exploitables. La qualité des résultats des niveaux supérieurs est donc tributaire de celle du bas niveau. Nous tentons de répondre aux attentes des niveaux supérieurs d'un système de vision en leur fournissant des informations robustes, exploitables et aussi proches que possible de la scène observée. Nous proposons un système complet de traitement bas niveau d'images à niveau de gris. Une image est décrite à plusieurs échelles (détection multi-échelle) en termes de jonctions et de contours avec une précision subpixel. Un algorithme de fermeture de contours fait coopérer les contours et les jonctions détectés. Notre système est fonde sur des études originales de comportement de modèles d'indices vis-à-vis d'un détecteur de contours
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VIANELLO, JULIANO MELQUIADES. "MOTION ESTIMATION METHOD WITH SUBPIXEL RESOLUTION OF CODEC H264/AVC." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2007. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=10168@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>Foi desenvolvido pelos grupos MPEG (Moving Picture Expert
Group) e
VCEG (Video Coding Expert Group) um novo padrão de
codificação de vídeo
denominado AVC (Advanced Vídeo Coding). Este padrão
fornece uma
capacidade de compressão maior de vídeo se comparado com
os padrões
anteriores. A estimação de movimento é a fase da
codificação de vídeo que
demanda maior tempo de processamento. Estimação de
movimento é
computacionalmente custosa para H.264/AVC se o método Full
Search [1] é
usado. A fim de reduzir o tempo de codificação, o software
de referência JM 9.8
adota um rápido método de estimação de movimento para
pixel inteiro chamado
UMHexagonS e um método para pixel fracionário chamado
CBFPS. Um método
proposto por Xiaoquan Yi, Jun Zhang, Nam Ling e Weijia
Shang [2] chamado
aqui, por simplicidade, de P021 apresenta, em comparação
com o software de
referência JM, uma melhor e simplificada forma de
estimação de movimento
para aumentar a velocidade do processo de codificação e
manter a qualidade
visual do vídeo. Visando diminuir ainda mais o tempo de
processamento e o
custo computacional apresentada pelos métodos citados
anteriormente, o que é
necessário principalmente para aplicações de codificação
de vídeo móveis, como
celulares e palm tops e aplicações de tempo real, como
videoconferência, este
trabalho propõe um método de estimação de movimento que
consiste em evitar o
processamento de blocos que não se beneficiam da pesquisa
de metade de pixel.
Após a execução dos testes, pode-se constatar que com uma
qualidade de vídeo
semelhante, o método proposto reduz o tempo de
processamento em 76,17%,
75,95% e 11,74% em média quando comparado com os métodos
Full Search,
JM 98 e P021. Além disso, este método praticamente
preserva a taxa de bits,
apresentando um pequeno aumento de 8,72% , 8,06% e 8,02%
em média quando
comparado com os mesmos métodos. Isto representa, em nossa
opinião, um
pequeno preço a ser pago, considerando os benefícios em
termos de tempo de
processamento.<br>The MPEG (Moving Picture Experts Group) and the VCEG (Video
Coding Experts Group) have developed a new video
compression standard
entitled AVC (Advanced Video Coding). This standard offers
the capacity of
video compression greater than the previous standards.The
motion estimation
which is a phase of the video compression is extremely
computer-intensive and
therefore demands most of the processing time. When Full
Search [1] method is
used for H.264/AVC, this process is extremely expensive.
In order to reduce
encoding time, the reference software JM (throughout this
work, JM98 is the
version used) has respectively adopted a fast motion
estimation method for the
integer pixel called UMHexagonS and a method for the sub-
pixel called CBFPS.
A method proposed by Xiaoquan Yi, Jun Zhang, Nam Ling e
Weijia Shang [2]
called here P021 (as referenced by the Joint Video Team)
has shown, when
compared to the reference software JM, a simple way of
motion estimation that
increases the speed of coding process while maintaining
the video visual quality.
In order to decrease the processing time and computational
cost of these
methods, which are: i) particularly needed in mobile video
coding applications
such as mobile phones and palmtops; ii) in real time
applications such as
videoconference, this work proposes a motion estimation
method that eliminates
the processing of blocks that does not produce benefits
for the half-pixel search.
The simulation results show that the proposed method
reduces the processing
time in 76,17%, 75,95% and 11,74% in average when
respectively compared
with Full Search, JM98 and P021 methods, without relevant
impact in video
quality. Besides, this method produces a bits rate
increase of 8,72% , 8,06% e
8,02% in average when compared with the same methods. This
is in our opinion,
an inexpensive price to be paid when the time benefits are
considered.
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Fristot, Vincent. "Métrologie par stéréovision : acquisition synchrone et précision subpixel pour la calibration." Grenoble INPG, 1992. http://www.theses.fr/1992INPG0072.
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La vision stereoscopique - stereovision - est un moyen pratique et efficace pour mesurer des objets tridimensionnels. Le principe de la photogrammetrie constitue le fondement du systeme de vision developpe. Nous etudions une modelisation pour la prise de vues qui permettra la reconstruction de scenes tridimensionnelles. Une methode de calibration est proposee, celle-ci se base sur les proprietes physiques des cameras utilisees. Les cartes d'acquisition d'images du marche n'exploitent pas toute l'information geometrique de l'image issue des cameras ccd. Nous montrons que l'acquisition synchrone avec l'horloge pixel permet un gain important en precision. Par consequent, des algorithmes de precision (subpixel) pour la localisation d'objets sont mis en uvre. Ces resultats s'approchent de ceux obtenus par photogrammetrie a partir de cliches photographiques. Nous presentons une application industrielle qui integre tous ces elements. Notre travail entraine une amelioration de la vitesse et de la precision des mesures en atteignant quasiment la limite technologique des capteurs employes
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Foschi, Patricia G. "Classification of subpixel woody vegetation in remotely-sensed imagery of lowland Britain." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386456.
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Sandersfeld, Michelle R. "Detection of Subpixel Submerged Mine-Like Targets in WorldView-2 Multispectral Imagery." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/17458.
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Approved for public release; distribution is unlimited<br>The utility of satellite spectral imagery is analyzed for the detection of submerged mine like objects. The targets that were utilized were sub-meter in size and emplaced in the water off the coast of La Jolla, California for a barnacle study. There were three surface targets and three submerged targets that did not exceed three meters in depth. Two meter multispectral and half meter panchromatic WorldView-2 data were used for image processing and analysis. The multispectral data proved more useful than the higher spatial resolution panchromatic data (sub-pixel vs resolved).For the multispectral data, principal component analysis was the most successful of the techniques, locating the submerged and surface targets. Attempts to use the RX-UTD anomaly detector were less successful, because of excessive false positives. This study supports the concept that commercial remote sensing is a viable option to support mine countermeasures.
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Rivero, Daniel. "Mesure en temps réel de position à précision subpixel dans une image." Dijon, 1999. http://www.theses.fr/1999DIJOS006.
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Plusieurs applications de métrologie nécessitent un calcul précis des positions d'intersections de barres. Le système que nous avons développé et que nous présentons dans ces travaux est un système de mesure embarqué calculant en temps réel la position des intersections de barres avec une précision subpixel dans des images de 1024 1024 pixels fournis par une caméra dont la fréquence d'horloge est de 50 mhz. Le système auquel nous sommes parvenus est bâti autour d'un algorithme recherchant rapidement les zones d'intersection et qui traite ensuite uniquement dans ces zones les informations afin de modéliser les deux barres horizontale et verticale par deux droites. L'intersection de ces deux droites est considérée comme correspondant à la position de l'intersection. Pour respecter la contrainte de temps réel et dans le but de trouver une solution matérielle minimale, nous avons développé une architecture hybride dans laquelle il résulte que les tâches de bas niveau comme les calculs de centres de gravite sont implantées sur FPGA et les autres taches sur DSPs. La solution développée permet de disposer des résultats dès la fin du transfert des données de la camera (20 ms).
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Elbakary, Mohamed Ibrahim. "Novel Pixel-Level and Subpixel-Level Registration Algorithms for Multi-Modal Imagery Data." Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1293%5F1%5Fm.pdf&type=application/pdf.
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Kellner, Michael. "Zeitliche Konturgraphverfolgung /." Duisburg ; Köln : WiKu-Verl, 2007. http://d-nb.info/986261599/04.
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Manslow, John. "On the extraction and representation of land cover information derived from remotely sensed imagery." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342773.
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Sabater, Neus. "Fiabilité et précision en stéréoscopie : application à l'imagerie aérienne et satellitaire à haute résolution." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2009. http://tel.archives-ouvertes.fr/tel-00505143.
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Cette thèse se situe dans le cadre du projet MISS (Mathématiques de l'Imagerie Stéréoscopique Spatiale) monté par le CNES en collaboration avec plusieurs laboratoires universitaires en 2007. Ce projet se donne l'objectif ambitieux de modéliser un satellite stéréoscopique, prenant deux vues non simultanées mais très rapprochées de la Terre en milieu urbain. Son but principal est d'obtenir une chaîne automatique de reconstruction urbaine à haute résolution à partir de ces deux vues. Ce projet se heurte toutefois à des problèmes de fond que la présente thèse s'attache à résoudre. Le premier problème est le rejet des matches qui pourraient se produire par hasard, notamment dans les zones d'ombres ou d'occlusion, et le rejet également des mouvements au sol (véhicules, piétons, etc.). La thèse propose une méthode de rejet de faux matches basée sur la méthodologie dite a contrario. On montre la consistance mathématique de cette méthode de rejet, et elle est validée sur des paires simulées exactes, sur des vérités terrain fournies par le CNES, et sur des paires classiques de benchmark (Middlebury). Les matches fiables restants représentent entre 40% et 90% des pixels selon les paires testées. Le second problème de fond abordé est la précision. En effet le type de stéréoscopie envisagé exige un très faible angle entre les deux vues, qui sont visuellement presque identiques. Pour obtenir un relief correct, il faut effectuer un recalage extrêmement précis, et calibrer le niveau de bruit qui permet un tel recalage. La thèse met en place une méthode de recalage subpixélien, qui sera démontrée être optimale par des arguments mathématiques et expérimentaux. Ces résultats étendent et améliorent les résultats obtenus au CNES par la méthode MARC. En particulier, il sera montré sur les images de benchmark Middlebury que la précision théorique permise par le bruit correspond bien à celle obtenue sur les matches fiables. Bien que ces résultats soient obtenus dans le cadre d'un dispositif d'acquisition précis (stéréoscopie aérienne ou satellitaire à faible angle), tous les résultats sont utilisables en stéréoscopie quelconque, comme montré dans beaucoup d'expériences.
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Michalik, Sören [Verfasser], and Mladen [Akademischer Betreuer] Berekovick. "Hardware-beschleunigte Bildmerkmale mit Subpixel-Genauigkeit zur SLAM Lokalisierung und Objekterkennung / Sören Michalik ; Betreuer: Mladen Berekovick." Braunschweig : Technische Universität Braunschweig, 2019. http://d-nb.info/1176701312/34.
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Vander, Jagt Benjamin J. "On the characterization of subpixel effects for passive microwave remote sensing of snow in montane environments." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1449233895.
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Zheng, Xiang. "Optimization of Sampling Structure Conversion Methods for Color Mosaic Displays." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31189.
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Although many devices can be used to capture images of high resolution, there is still a need to show these images on displays with low resolution. Existing methods of subpixel-based down-sampling are reviewed in this thesis and their limitations are described. A new approach to optimizing sampling structure conversion for color mosaic displays is developed. Full color images are filtered by a set of optimal filters before down-sampling, resulting in better image quality according to the SCIELAB measure, a spatial extension of the CIELAB metric measuring perceptual color difference. The typical RGB stripe display pattern is tested to get the optimal filters using least-squares filter design. The new approach is also implemented on a widely used two-dimensional display pattern, the Pentile RGBG. Clear images are produced and color fringing artifacts are reduced. Quality of down-sampled images are compared using SCIELAB and by visual inspection.
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Balci, Murat. "SUB-PIXEL REGISTRATION IN COMPUTATIONAL IMAGING AND APPLICATIONS TO ENHANCEMENT OF MAXILLOFACIAL CT DATA." Doctoral diss., University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3548.
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In computational imaging, data acquired by sampling the same scene or object at different times or from different orientations result in images in different coordinate systems. Registration is a crucial step in order to be able to compare, integrate and fuse the data obtained from different measurements. Tomography is the method of imaging a single plane or slice of an object. A Computed Tomography (CT) scan, also known as a CAT scan (Computed Axial Tomography scan), is a Helical Tomography, which traditionally produces a 2D image of the structures in a thin section of the body. It uses X-ray, which is ionizing radiation. Although the actual dose is typically low, repeated scans should be limited. In dentistry, implant dentistry in specific, there is a need for 3D visualization of internal anatomy. The internal visualization is mainly based on CT scanning technologies. The most important technological advancement which dramatically enhanced the clinician's ability to diagnose, treat, and plan dental implants has been the CT scan. Advanced 3D modeling and visualization techniques permit highly refined and accurate assessment of the CT scan data. However, in addition to imperfections of the instrument and the imaging process, it is not uncommon to encounter other unwanted artifacts in the form of bright regions, flares and erroneous pixels due to dental bridges, metal braces, etc. Currently, removing and cleaning up the data from acquisition backscattering imperfections and unwanted artifacts is performed manually, which is as good as the experience level of the technician. On the other hand the process is error prone, since the editing process needs to be performed image by image. We address some of these issues by proposing novel registration methods and using stonecast models of patient's dental imprint as reference ground truth data. Stone-cast models were originally used by dentists to make complete or partial dentures. The CT scan of such stone-cast models can be used to automatically guide the cleaning of patients' CT scans from defects or unwanted artifacts, and also as an automatic segmentation system for the outliers of the CT scan data without use of stone-cast models. Segmented data is subsequently used to clean the data from artifacts using a new proposed 3D inpainting approach.<br>Ph.D.<br>School of Electrical Engineering and Computer Science<br>Engineering and Computer Science<br>Computer Science
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De, Rosa Andrea. "Metodo di Edge-Detection basato sul calcolo di aree parziali." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15805/.
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In questo lavoro, viene proposto un metodo di Edge-Detection, in immagini rumorose e con sfuocamento. Il problema è stato posto da Marposs, che fornisce sistemi di misura di alta precisione, quindi è stato necessario applicare un metodo di detezione di edges a livello subpixel. È stato utilizzato il funzionale di Perona Malik per il metodo di denoising e un metodo basato sul calcolo di aree parziali per il subpixed edge detection. Il metodo raggiunge dei buoni risultati anche in situazioni di alto di rumore e sfocamento. Verranno mostrati risultati sia riguardo all'accuratezza dell'edge-detection di contorni rettilinei, con varie inclinazioni, che riguardo la ripetibilità. Infine verranno accennati alcuni risultati nel caso di edge curvilinei e possibili sviluppi futuri per migliorarne le prestazioni.
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Rosenius, Magnus. "Controlling the speed of film with high precision in a line scanner." Thesis, Linköping University, Department of Electrical Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1776.
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<p>In this master thesis, a system has been designed that is used to detect the perforation holes on a film in a line-scanning film scanner. The film scanner is used to scan regular film taken by high-speed cameras during tests of for example missile launches or vehicle crash tests. </p><p>The system consists of a PLD that detects the perforation holes on the film using a signal from a digital line-scanning CCD camera. A main issue has been to make the detection procedure robust and independent of the different types of films encountered in real life situations. </p><p>The result from the detection is used to generate control signals to the film speed regulation mechanism inside the film scanner that then regulates the velocity of the film. To make the detection and regulation more sensitive, a part-of-line precision has been developed to calculate where, inside a line, the actual hole is positioned. </p><p>The system has been programmed in VHDL, synthesized, implemented and fitted into a Xilinx Spartan (XCS10-3-PC84) Field Programmable Gate Array (FPGA). The implementation has been simulated but not in real hardware.</p>
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Chakinala, Shilpa. "A Study of Algorithms Based on Digital Image Correlation for Embedding in a Full-Fiield Displacement Sensor with Subpixel Resolution." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1367102631.
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Čírtek, Jiří. "Sledování malých změn objektů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217199.
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This diploma thesis inspects problems with specification location of edges with higher accuracy then one pixel (subpixel accuracy). In terms of this assignment has been created program, which generates three different shapes of objects. With change of parameters in program is measuring location of gravitational center on objects with subpixel accuracy. Obtained data of gravitational center deviations are depictured in graphs.
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Skoglund, Johan. "Robust Real-Time Estimation of Region Displacements in Video Sequences." Licentiate thesis, Linköping : Department of Electrical Engineering, Linköpings universitet, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8006.
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Mtimet, Habib. "Analyse fréquentielle d'image pour une résolution subpixel : Etude d'un système nanolidar appliqué à la localisation des défauts dans les composants III-V." Montpellier 2, 1994. http://www.theses.fr/1994MON20018.
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La resolution des images recueillies par les capteurs ccd est limitee d'une part par le phenomene de diffraction du systeme optique utilise et d'autre part par un phenomene de double quantification: spatiale et dynamique, subi par l'image. Ces deux limitations physiques sont considerees afin d'obtenir une meilleure precision. Deux methodes de super resolution centroide et glissement de la phase de fourier (fps) sont etudiees et comparees grace a une simulation. Une resolution subpixel concernant la localisation du centre d'une image est obtenue. L'etude est ensuite generalisee a la realisation experimentale d'un systeme nanolidar destine a localiser avec une grande precision les microprecipites dans les composants iii-v. Des images de diffraction d'un microprecipite pour differents plans de defocalisation sont acquises, formant ainsi un signal tridimensionnel: la reponse impulsionnelle (psf) du systeme optique utilise. Un logiciel de calcul de la transformee de fourier tridimensionnelle (fft 3-d) est developpe. Applique aux images de diffraction, ce logiciel permet a partir de la phase du spectre de fourier obtenu (fto 3-d du systeme optique), la localisation, a l'echelle submicronique, des microprecipites dans les materiaux. La precision evaluee est nanometrique
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Kohoutek, Michal. "Metoda fyzikálního modelování přechodových hran v obraze pro určení skutečné pozice obrysu předmětu." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-233452.
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Doctoral thesis is focused on a design of a new original image transition edge physical modeling method for exact object shape position determination. Automatic Optical Inspection systems for the high accuracy optical measurements is main application area for designed method. The new method design is based on precise physical analysis of a defined imaging system. Object side telecentric lens, telecentric backlight source and CCD video camera are main parts of the analyzed imaging system. New image transition edge physical model and method for accurate shape position detection within the model are derived by geometrical and Fourier optics imaging system analysis. Possible influences of the model parameters changes to the accuracy of shape position detection are studied precisely. A new modeling function suitable for implementation in a new optimal approximation method is derived from the physical transition edge model. The modeling function optimal approximation method is implemented in to a Tester2D measuring system and verified by length etalon measurements. The Tester2D measuring system was successfully accredited for dimensions measurement in range with accuracy up to . Documentation of results of the accreditation process with the record of obtained results from measurement system in scope of preformed interlaboratory comparison tests are appended to the doctoral thesis.
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Estrada, Perez Carlos Eduardo. "Analysis, comparison and modification of various Particle Image Velocimetry (PIV) algorithms." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1532.
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A program based on particle tracking velocimetry (PTV) was developed in this work. The
program was successfully validated by means of artificial images where parameters such as radius,
concentration, and noise were varied in order to test their influence on the results. This program
uses the mask cross correlation technique for particle centroid location. The sub-pixel accuracy is
achieved using two different methods, the three point Gaussian interpolation method and the center
of gravity method. The second method is only used if the first method fails. The object matching
algorithm between frames uses cross correlation with a non binarized image.
A performance comparison between different particle image velocimetry (PIV) and PTV algorithms
was done using the international standard PIV challenge artificial images. The best
performance was obtained by the program developed in this work. It showed the best accuracy,
and the best spatial resolution by finding the larger number of correct vectors of all algorithm
tested.
A procedure is proposed to obtain error estimates for real images based on errors calculated
with experimental ones. Using this procedure a real PIV image with 20% noise has an estimated
average error of 0.1 pixel.
Results of the analysis of 200 experimental images are shown for the two best PTV algorithms.
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Daemi, Bita. "Enhanced image analysis, a tool for precision metrology in the micro and macro world." Doctoral thesis, KTH, Industriell produktion, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-207594.
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The need for high speed and cost efficient inspection in manufacturing lineshas led to a vast usage of camera-based vision systems. The performance ofthese systems is sufficient to determine shape and size, but hardly to an accuracylevel comparable with traditional metrology tools. To achieve highprecision shape/position/defect measurements, the camera techniques haveto be combined with high performance image metrology techniques whichare developed and adapted to the manufactured components. The focus ofthis thesis is the application of enhanced image analysis as a tool for highprecision metrology. Dedicated algorithms have been developed, tested andevaluated in three practical cases ranging from micro manufacturing at submicronprecision to meter sized aerospace components with precision requirementsin the 10 μm range.The latter measurement challenge was solved by low cost standard consumerproducts, i.e. digital cameras in a stereo configuration and structured lightfrom a gobo-projector. Combined with high-precision image analysis and anew approach in camera calibration and 3D reconstruction for precise 3Dshape measurement of meter sized surfaces, the achievement was fulfilledand verified by two conventional measurement systems; a high precisioncoordinate measurement machine and a laser scanner.The sub-micron challenge was the implementation of image metrology forverification of micro manufacturing installations within a joint Europeaninfrastructure network, EUMINAfab. The results were an unpleasant surprisefor some of the participating laboratories, but became a big step forwardto improve the dimensional accuracy of the investigated laser micromachining, micro milling and micro-printing systems, since the accuracy ofthese techniques are very difficult to assess.The third high precision metrology challenge was the measurement of longrange,low-amplitude topographic structures on specular (shiny) aerodynamicsurfaces. In this case Fringe Reflection Technique (FRT) was appliedand image analysis algorithms were used to evaluate the fringe deformationas a measure of the surface slopes to obtain high resolution data. The resultwas compared with an interferometric analysis showing height deviation inthe range of tens of micrometers over a lateral extension of several cm.<br><p>QC 20170523</p><br>LOCOMACHS<br>EUMINAfab<br>Cleansky
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Cai, Guangcheng. "Le suivi de l'objet mobile et l'algorithme du bloc estimé." Ecully, Ecole centrale de Lyon, 2005. http://bibli.ec-lyon.fr/exl-doc/gcai.pdf.
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Dans cet article nous proposons une méthode qui permet d'identifier et de suivre l'objet cible à partir des données digitales MPEG. Cette méthode consiste à récupérer les informations sur le vecteur de mouvement de chaque macrobloc en mouvement puis identifier les objets mobiles avec la méthode de la croissance régionale des vecteurs de mouvement. Cette méthode évite les problèmes liés à la forme, à la couleur et à la taille de l'objet. Notre technique utilise la transformation de Hough rapide et les caractéristiques géométriques de la zone de texte pour extraire les informations de la publicité des images de programme sportif sur TV. La corrélation de Speckle Digital qu'on utilise dans la mesure optique est la technique d'adaptation bloc du traitement d'image. Nous pouvons déduire la valeur de déplacement de subpixel avec la formule d'interpolation et comparer la précision théorique et la stabilité de la méthode d'interpolation parabolique et la méthode de gradient<br>Moving object detection and tracking is a major issue in many vision systems. Since features of MPEG, our paper presents a novel mehtod that directly detects and tracks the moving object in video from MPEG coded data fluid. Our method can fully make use of the temporal and spatial correlation between I and P frame, and effectively avoid the difficult of change of shape, color and background of moving object. Precise visibility measuring of billboard advertising is a key element for the organizers and broadcasters to make cost effective their sport live relay. Our technique makes use of fast Hough transform and text's geometry features in order to extract advertisement from sport TV images. Digital Speckle Correlation Method has been applied to an optical measurement. This paper discusses the theory precision of the quadratic interpolation and the gradient method from mathematics theory. And we ameliorate their formula from discrete integer aspect
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Crusius, Marcelo Ughini. "Transecção subpial múltipla na epilepsia focal experimental." Pontifícia Universidade Católica do Rio Grande do Sul, 2009. http://hdl.handle.net/10923/4443.
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Previous issue date: 2009<br>Object. Epilepsy is an occurrence of repetitive crises in absence of toxicmetabolic disturb, causing from a brain abnormal electrical activity. It can be secondary, caused by cerebral structural lesion (tumors, gliosis areas, malformations etc), or from de genetic mutation with repercussion in neuronal excitability. The mayor part of epileptic crisis has a good response from medical treatment. However, 20-30% of epilepsy is refractory from medical treatment. Those patients are candidates to epilepsy surgery, who aim at resects areas where crisis start. When this resection is not possible like in eloquent area, an alternative is a surgical procedure called multiple subpial transection (MST), which interrupts the neuronal horizontal connections, getting down the intracortical propagation of ictal epileptic discharges. The goal in this study was valuate the efficacy of TSM in the control of crises in epilepsy focal experimental model. Methods. We used 25 Wistar male rats, with 60-150 days of life, from Instituto de Pesquisas Biomédicas da Pontifícia Universidade Católica do Rio Grande do Sul, who seved like focal epilepsy model. The animals were kept under controlled illumination and temperature. After anesthetic procedure the animals were fixed in the stereotaxic apparatus and left craniotomy and Dura-mater were take out, than five electrodes were fixed at the cerebral cortex and video-electroencephalogram (video-EEG) were registered for 10 min. At this point we injected penicillin G potassic crystalline subpial in the same local to the most anterior electrode who was always in the forelimb motor cortex, than we registered 10 min video-EEG. After that procedure we divided in two groups: experimental group who we did a Multiple Subpial Trasection(MST) and a Sham group who we did not do MST, in both of that we registered 10 min video-EEG. Results. The time to get seizures had the same median in a surgical group and in the control group (180s). The rats which stopped crisis in the surgical group was 10 (66,7%) and in control group no one. Two animals (11,1%) died in a surgical group and 4(57,1%) in a control group. In the channel 3 the median post- TSM was 7(1 to 16) and in the end of register of control group 20 (6 to 35), p=0,012. For the interictal discharges in a surgical group the median post-penicillin against post-TSM was 17 (p<0,001), in the control group was 14 post-penicillin and in the end of the register 20 (p=0,091). Median in the surgical group for the post-penicillin was 1(0 to 6) and 0(0 to 1) (p=0,003).For the ictal discharges in the surgical group the median post-penicillin was 1 and post-TSM was 0 (p=0,003). There was not motor deficit after procedure in any animals; also there was no significant histological alteration in the rats. Conclusion. These findings suggest a role of MST stop or decrease tremendously the electrical spreading of epilepsy crisis in brain cortical layer of rats. It demonstrates that it is a very effective surgical therapy for refractory epilepsy focused on cerebral eloquent areas.<br>Fundamentos: Epilepsia, por conceito, é a ocorrência de crises repetitivas na ausência de distúrbio tóxico-metabólico, decorrente de uma atividade elétrica anormal do encéfalo. Pode ser secundária, causada por lesão cerebral estrutural (tumores, áreas de gliose, malformações, etc. ), ou decorrente de mutação genética com repercussão na excitabilidade neuronal. A maior parte das crises epilépticas responde bem ao tratamento medicamentoso; entretanto, 20-30% das epilepsias são refratárias ao tratamento medicamentoso. Estes pacientes são candidatos à cirurgia da epilepsia, a qual visa à ressecção da área de início das crises. Quando essa ressecção não é possível, como em áreas cerebrais eloqüentes, uma alternativa é o procedimento cirúrgico denominado de transecção subpial múltipla (TSM), que interrompe as conexões neuronais horizontais, reduzindo a propagação intracortical das descargas epilépticas ictais. Objetivo geral: Avaliar a eficácia da TSM no controle das crises epiléticas num modelo de epilepsia focal experimental. Materiais e métodos: Foi realizado um estudo experimental com intervenção, no qual foram estudados 25 ratos machos da raça Wistar, com idade aproximadamente entre 60-150 dias, divididos em dois grupos e submetidos a implante de eletrodos de registro eletrencefalográfico e indução de foco epiléptico por injeção de penicilina G potássica cristalina subpial. No Grupo I (Experimental) os animais foram submetidos à craniectomia monitorados por vídeo-EEG por 10 minutos, induzidos ao foco epilético e videomonitorizados pelo mesmo período; após, foram submetidos à TSM e novamente videomonitorados por 10 minutos. No Grupo II (Sham), os animais foram submetidos à craniectomia, submetidos por 10 minutos a vídeo-EEG; após, o foco epilético foi induzido, mas não foi realizada a TSM, sendo novamente submetidos a 10 minutos de vídeo-EEG. Todos os animais foram submetidos a estudo histológico para avaliação da vascularização e da organização estrutural do córtex cerebral.
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Boukhtache, Seyfeddine. "Système de traitement d’images temps réel dédié à la mesure de champs denses de déplacements et de déformations." Thesis, Université Clermont Auvergne (2017-2020), 2020. http://www.theses.fr/2020CLFAC054.
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Cette thèse s’inscrit dans un cadre pluridisciplinaire. Elle traite de la problématique du temps réel et de celle des performances métrologiques en traitement d’images numériques. Elle s'intéresse plus particulièrement à la photomécanique. Il s'agit d'une discipline récente visant à développer et à utiliser au mieux des systèmes de mesure de champs entiers de petits déplacements et de petites déformations en surface de solides soumis à des sollicitations thermomécaniques. La technique utilisée dans cette thèse est la corrélation des images numériques (CIN), qui se trouve être l'une des plus employées dans cette communauté. Elle représente cependant des limitations à savoir un temps de calcul prohibitif et des performances métrologiques améliorables afin d'atteindre celles des capteurs ponctuels classiques comme les jauges de déformation.Ce travail s'appuie sur deux axes d'étude pour relever ce défi. Le premier repose sur l'optimisation de l'interpolation d'images qui est le traitement le plus coûteux dans la CIN. Une accélération est proposée en utilisant une implémentation matérielle parallélisée sur FPGA, tout en tenant compte de la consommation des ressources matérielles et de la précision. La principale conclusion est qu'un seul FPGA (dans les limites technologiques actuelles) ne suffit pas à implémenter l'intégralité de l'algorithme CIN. Un second axe d'étude a donc été proposé. Il vise à développer et à utiliser des réseaux de neurones convolutifs pour tenter d'atteindre à la fois des performances métrologiques meilleures que la CIN et un traitement en temps réel. Cette deuxième étude a montré l'efficacité d'un tel outil pour la mesure des champs de déplacements et de déformations. Elle ouvre de nouvelles perspectives en termes de performances métrologiques et de rapidité des systèmes de mesure de champs<br>This PhD thesis has been carried out in a multidisciplinary context. It deals with the challenge of real-time and metrological performance in digital image processing. This is particularly interesting in photomechanics. This is a recent field of activity, which consists in developing and using systems for measuring whole fields of small displacements and small deformations of solids subjected to thermomechanical loading. The technique targeted in this PhD thesis is Digital Images Correlation (DIC), which is the most popular measuring technique in this community. However, it has some limitations, the main one being the computing resources and the metrological performance, which should be improved to reach that of classic pointwise measuring sensors such as strain gauges.In order to address this challenge, this work relies on two main studies. The first one consists in optimizing the interpolation process because this is the most expensive treatment in DIC. Acceleration is proposed by using a parallel hardware implementation on FPGA, and by taking into consideration the consumption of hardware resources as well as accuracy. The main conclusion of this study is that a single FPGA (current technology) is not sufficient to implement the entire DIC algorithm. Thus, a second study has been proposed. It is based on the use of convolutional neural networks (CNNs) in an attempt to achieve both better metrological performance than CIN and real-time processing. This second study shows the relevance of using CNNs for measuring displacement and deformation fields. It opens new perspectives in terms of metrological performance and speed of full-field measuring systems
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Crusius, Marcelo U. "Transec??o subpial m?ltipla na epilepsia focal experimental." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2009. http://tede2.pucrs.br/tede2/handle/tede/1514.
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Previous issue date: 2009-03-26<br>FUNDAMENTOS: Epilepsia, por conceito, ? a ocorr?ncia de crises repetitivas na aus?ncia de dist?rbio t?xico-metab?lico, decorrente de uma atividade el?trica anormal do enc?falo. Pode ser secund?ria, causada por les?o cerebral estrutural (tumores, ?reas de gliose, malforma??es, etc.), ou decorrente de muta??o gen?tica com repercuss?o na excitabilidade neuronal. A maior parte das crises epil?pticas responde bem ao tratamento medicamentoso; entretanto, 20-30% das epilepsias s?o refrat?rias ao tratamento medicamentoso. Estes pacientes s?o candidatos ? cirurgia da epilepsia, a qual visa ? ressec??o da ?rea de in?cio das crises. Quando essa ressec??o n?o ? poss?vel, como em ?reas cerebrais eloq?entes, uma alternativa ? o procedimento cir?rgico denominado de transec??o subpial m?ltipla (TSM), que interrompe as conex?es neuronais horizontais, reduzindo a propaga??o intracortical das descargas epil?pticas ictais. OBJETIVO GERAL: Avaliar a efic?cia da TSM no controle das crises epil?ticas num modelo de epilepsia focal experimental. MATERIAIS E M?TODOS: Foi realizado um estudo experimental com interven??o, no qual foram estudados 25 ratos machos da ra?a Wistar, com idade aproximadamente entre 60-150 dias, divididos em dois grupos e submetidos a implante de eletrodos de registro eletrencefalogr?fico e indu??o de foco epil?ptico por inje??o de penicilina G pot?ssica cristalina subpial. No Grupo I (Experimental) os animais foram submetidos ? craniectomia monitorados por v?deo-EEG por 10 minutos, induzidos ao foco epil?tico e videomonitorizados pelo mesmo per?odo; ap?s, foram submetidos ? TSM e novamente videomonitorados por 10 minutos.No Grupo II (Sham), os animais foram submetidos ? craniectomia, submetidos por 10 minutos a v?deo-EEG; ap?s, o foco epil?tico foi induzido, mas n?o foi realizada a TSM, sendo novamente submetidos a 10 minutos de v?deo-EEG. Todos os animais foram submetidos a estudo histol?gico para avalia??o da vasculariza??o e da organiza??o estrutural do c?rtex cerebral.
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Martin, Miguel Maria del Carmen. "Study of epileptiform activity, interhemispheric latency and propagation patterns in patients with Landau Kleffner syndrome (LKS) undergoing multiple subpial transection (MST)." Thesis, King's College London (University of London), 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423029.
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Cheng, I.-Ta, and 鄭義達. "Image Demosaicking and Subpixel-based Downsampling." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/07017953395408110375.
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Guo, Yan-Hong, and 郭晏宏. "Subpixel Image Alignment Using Interpolation Functions." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/39791825430648558551.
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碩士<br>國立成功大學<br>電腦與通信工程研究所<br>94<br>BGA (Ball Grid Array), a technology of packaging, is widely used in the manufacturing process of integrated circuits because it can offer better electrical and thermal performance. In order to identify the model name and function of each IC chip, the laser marking is used to generate patterns on the surface of the BGA package. But good marking relies on accurate alignment for IC package. In this thesis, a subpixel alignment method for BGA images is proposed to measure the central position and orientation angle of an IC package for the location of the etched mark through an image inspection system.
In the proposed method, region projection is first applied to generate vertical and horizontal projection profiles and recognize the contour of the object within the inspected area and delimit the regions of interest (ROI) by the projection profiles. Then the DOB (Difference of Boxes) filter is used to detect edge elements of the object. Further, the edge elements resulting from flaws or cracks on object’s boundaries are filtered out by the edge following method. Next, in order to achieve sub-pixel accuracy, a deterministic sub-pixel edge detection method using interpolation functions is used to modify the edge elements. Finally, the central position and orientation angle are obtained by the LSE line fitting algorithm followed geometric computation.
Our proposed method is evaluated in terms of the stability, accuracy and running time for synthetic images. The experimental result for noiseless synthetic images show that the error of the central position and orientation can be less than 0.07 pixel and 0.01 degree, respectively; for synthetic images under various levels of Gaussian noise corruption, the error standard deviation of the central position and the orientation are all less than 1%. The running time is measured with a Pentium 4 processor of 2.8 GHz, it takes approximately 41 milliseconds to complete the entire the alignment process for a inspection area in our sample images.
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Lee, Ching-Hai, and 李靖海. "Subpixel Analysis Techniques in Hyperspectral Image." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/11437822788471707191.
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博士<br>國防大學中正理工學院<br>國防科學研究所<br>89<br>For remote sensing on earth, it is necessary to identify surface materials and estimate their abundance. In the past, multispectral images only gave rough analysis owing to its low spectral resolution. Therefore, by using these images, it is only suitable to estimate and analyze a large area with few features. Recently, great progresses in optical sensors brought the earth remote sensing into a new era of hyperspectral images. They provide high spectral resolution that makes the estimation of multiple materials in a mixed pixel possible. In this dissertation, two main subjects are studied: the determination and classification of materials in a hyperspectral image. At first, by using statistical multivariate linear regression and subspace partition theorem, two new methods are proposed to improve the performance of determining the total number of materials. Secondly, for subpixel target classification, a posteriori model coupled with error analysis capability is proposed by improving the performance achieved by a priori model. A few hyperspectral remote sensing and medical multispectral MRI images are adopted in the experiments to verify these proposed methods. Experimental results show promising performance for identification and classification.
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Guo, Wen Liang, and 郭溫良. "Precision inspection and measurement using subpixel values." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/85709055019286703524.
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XIE, SHI-WEN, and 謝石文. "Subpixel corner matching for 3-D motion estimation." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/24173924622988677998.
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LEE, Wen-Chia, and 李文加. "Subpixel BGA Images Alignment Based on Moment Methods." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/10127890008406942535.
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碩士<br>國立成功大學<br>電腦與通信工程研究所<br>93<br>BGA (Ball Grid Array), a technology of packaging, is widely used in the integrated circuits. The model name and function of each IC chip through laser marking are to be identified by recognizing the etched mark on package surface. For instance, chip group, CPU, Flash, some communication IC etc. In order to achieve accurate alignment for the location of the etched mark, the central position and orientation angle of an IC package are examined through the image inspection system.
This thesis proposed a subpixel alignment method for BGA images. In the method, firstly, region projection is applied to recognize the contour of the object within the inspected area and delimit the regions of interest. Then the edge elements of the object can be found by using DOB (Difference of Boxes). Moreover, the edge elements resulting from cracks or flaws on object’s boundaries are filtered out by edge following method. Next, the edge elements are modified by ZOM (Zernike Orthogonal Moment) to achieve subpixel accuracy. Finally, the central position and orientation angle are obtained by the LSE line fitting algorithm followed by geometric computation.
Our proposed method is evaluated in terms of the stability and accuracy under noise degradation for synthetic images. The experimental results show that the error of the central position and the orientation is within ±0.1 pixel and within ±0.01 degree respectively without noise; the error standard deviation of the central position and the orientation are all less than 1.6% under various levels of Gaussian noise corruption. On running performance, it takes approximate 109 ms to complete the entire process for an inspected area of 360×300 pixels while running on a PC equipped with a processor of Pentium 4 3.0GHz.
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Cheng, Wen-Wei, and 鄭文瑋. "An Edge Detector with Subpixel Accuracy and Its Applications." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/nh334m.
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碩士<br>銘傳大學<br>資訊傳播工程學系碩士班<br>93<br>There are sharps and blur case after enlarge images, it is the most important problem of traditional image enlargement technology. Therefore, it will decrease the resolution and accuracy of images.
Because of the above-mentioned, we propose an edge detection algorithm with subpixel accuracy. The method includes two steps: 1.image is processed by Sobel edge detection method first that extracts probable edge points. Next, a subpixel accuracy edge detector is used to estimate the edge equation and gray values both sides of the edge automatically, and use them to enlarge the image. The main advantages are that edges can keep distinct when image was enlarged and edge points recovered from noise images.
In this thesis, our points are finding the real image edges that before Gaussian blur effect, estimated the both side original gray value of edges, and it can be obtain the line equation of edges in real number, to enhance the accuracy of line equation, that could keep edges intact after image enlargement.
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Shu, Chin-Hao, and 徐俊豪. "Development of A New Robust Subpixel Edge Detection Technique." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/45496426819860108189.
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碩士<br>國立中興大學<br>機械工程學系<br>88<br>Subpixel edge detection method in machine vision mainly includes edge model and edge estimation method. Most of the conventional one-dimensional edge estimation methods use the ideal step or the two-sided exponential function as edge model and the center of shape method or the least-square method as edge estimation tool. Subpixel edges are estimated by one of the four cross combination approaches. When the images obtained are blurred or out of focus, the performances of these methods degrade tremendously.
In this thesis, the bipolar continuous function and the correlation method are adopted as new edge model and subpixel edge estimation approach, respectively. Performances comparisons among the four possible subpixel edge estimation methods are carried out by real experiments to improve the accuracy and robustness.
To further reduce the computing time of the one-dimensional methods, two new two-dimensional subpixel edge estimation methods are proposed in this study. In these two new approaches, the two-dimensional two-sided exponential function is chosen as the edge model. The two-dimensional least-square method and the correlation method are the estimation tools, respectively. Experimental results show that all the 1-D and 2-D estimation methods proposed outmatch the conventional methods both in system stability and computing time.
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Hu, Zhen-Hui, and 胡振煇. "Subpixel Registration of Straight-edged Shapes on High Contrast Images." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/19536062788374526590.
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Hsieh, Tung-Lin, and 謝東霖. "The Study of Using Subpixel Technology on Digital Image Measurement." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/84983965775040902834.
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碩士<br>國立清華大學<br>動力機械工程學系<br>91<br>As long as digital image has been captured, there is an innate limitation on resolution. Thus, in application of measuring image there are usually limited by hardware equipment and can’t be exactly measured. However, The image interpolation is the key technique to break this limitation. This research uses image enlargement technique to realize exactly measurement of subpixel precision, and hopes using software to assist hardware, and break the limitation of resolution on hardware. Due to the general subpixel measurements are from edge detection to enlarge edge, and then use edge detection again to get the image for measurement. However, because of the image sample in this paper is much simple, after using binary and then enlarging the image, measuring the image. It is obviously that we can shorten the time of measuring image on the production line. This paper discusses several existing interpolation enlargement algorithm, and realize these algorithm through program. It is hope that the image measuring software raised in this paper can apply to the real production line.
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Chen, Chih-hsiang, and 鄭志祥. "The Study on Image Inspection of Rice using Subpixel Measurements." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/37649135277988116744.
Full textAbstract:
碩士<br>國立中興大學<br>農業機械工程學系<br>90<br>The image processing techniques can be applied for the classification of variety and quality of agricultural products. The classification parameters include length, width, perimeter and area. The recognition function of the inspection will be improved depending on the precision and raised due to measured data. In this study, CCD camera with four scales 1/64, 1/16, 1/4 and 1 of resolutions was utilized to acquire images of rice kernels. The noise of image was removed by the median filter. The moment-preserving principle was applied to determine the thresholds automatically to reduce the effect of changes of the acquiring environment on length, width, perimeter and area.
A micrometer (10mm×10mm, 0.1mm grid) was applicated to calculate the length and width of rice using the projection image of each rice kernel. Two methods, the automatic thresholding and the sobel operator with LoG method were employed to detect the edge of rice image and to calculate its length and width. The experimental results obtained from both methods were then compared with that using the fixed threshold method.
The results show that the automatic thresholding is able to reduce the effect of variation of the light source. The use of LoG method can improve the resolution and measurement precision from pixel resolution to subpixel resolution. According to the Scheffe test of SAS, the percentage of errors measured by the automatic thresholding with LoG method were improved at scales of 1/64 (13.79×10-2 mm/pixel) and 1 (1.69×10-2 mm/pixel). To increase the inspection amount of rice kernels per image and to improve the inspection speed without reducing the precision, the automatic thresholding with LoG method is a superior way of edge detection for the four scales considered in this research. The choose of resolution can be determined by the requirement of the inspection precision, for instance, 108 rice kernels per image at scale 1/64 (13.79×10-2 mm/pixel) and 30 rice kernels per image at scale 1/16 (6.79×10-2 mm/pixel) that can achieve the inspection accuracy required.
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Su, Cherng Tzong, and 蘇成宗. "Applications of Machine Vision and Subpixel Techniques in Socket Inspection." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/31209123898528247791.
Full textAbstract:
碩士<br>國立清華大學<br>工業工程研究所<br>82<br>The employment of a machine vision system for part inspection
has become an important component for achieving the goal
of real-time control. However, one of the major
constraints of this technique is its limited accuracy
owing to the pixel resolution. For those applications
which require better accuracy, such as photogrammetry and
precision measurement, the accuracy can be improved by
replacing with better hardware devices or by applying the
subpixel techniques. In this research, we intend to develop
new machine vision techniques to solve the problems
encountered in practical manufacturing environment, with
emphasis on accuracy problem. Linear estimation for LOG
operation (LEFLO) method and weighted average (WA) method are
proposed in this research. The LEFLO method applies the
Laplacian of Gaussian convolution and localizes the edge
with linear interpolation. WA method uses the deviation of
gray values of successive pixels as the weight numbers to
estimate the gray level of the edge translation. In this
research, the synthetic images are employed to evaluate the
effectiveness of the algorithms. The experimental results
show that LEFLO is more accurate than WA when images are
not disturbed by the environmental noise. Nevertheless,
LEFLO is more sensitive to noise. The weighted average
method requires less processing time than LEFLO method.
It is almost one-sixty of the processing time of the LEFLO
method. Finally, an integrated system for socket inspection
is developed to illustrate its capability real-time
inspection.
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Yang, Mon-Da, and 楊孟達. "A Study of High-Precision Planar Calibration System with Subpixel Accuracy." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/17459155029064888032.
Full textAbstract:
碩士<br>國立交通大學<br>電機與控制工程系<br>88<br>The calibration of a camera in automation industry and computer vision is an indispensable step when high precision vision is used as measuring instrument.
To do this, one needs to localize the precise position with a maximum of accuracy for determining the movement of the testing pattern.
A calibration system proposed in this thesis can support to obtain precise feature points of the testing pattern in the digital image.
There are three major stages for this system: image preprocessing, reference points establishment, feature points extraction by using subpixel algorithm.
In the preprocessing stage, some statistical techniques are used to obtain the incoming image from image sequence.
Next, the reference coordinate is set up and the reference points are numbered.
Finally, the proposed fuzzy subpixel operator which resists noise better and provides more precision resolution is used to extract the edge equation,
then the location of feature points is estimated with subpixel accuracy.
Experimental results are provided to demonstrate proposed scheme with good calibration rate, and
the method can also be applied to estimate the precise position of the CCD sensor which is set up into the camera module correctly.
1.1 Surey
1.2 Motivation
1.3 Organization of the Thesis
2 Image Processing and Subpixel Precision Algorithm
2.1 Image Processing
2.1.1 Image Thresholding
2.1.2 Hough Transform
2.1.3 Median Filter
2.1.4 Run-Length Coding
2.2 Subpixel Precision Algorithm
2.2.1 One-Dimensional Edge Operator
2.2.2 Extension to Two-Dimensional Edge Patterns
2.3 Fuzzy Reasoning
3 High-Precision Technology Based on Subpixel Precision for Planar Calibration System
3.1 Statistical Preprocessing
3.2 Image Preprocessing
3.3 Reference Coordinate Establishment and Subpixel Equation
Quotation
3.3.1 Reference Coordinate Establishment
3.3.2 Subpixel Equation Quotation
3.4 Information Extraction
3.4.1 One-Dimensional Fuzzy subpixel operator
3.4.2 Extension to Two-Dimensional Subpixel Operator
3.4.3 Estimation Subpixel Feature points
3.4.4 Extension of Subpixel Operator and Resistance of
noise
4 Experimental Results
4.1 Experimental Environment
4.2 Experimental Results
5 Conclusions
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-Yuan, Chen Po, and 陳柏淵. "Subpixel Classification for Hyperspectral Imagery ---From Unknown Background to Blind Separation." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/86445021887590038109.
Full textAbstract:
博士<br>國防大學中正理工學院<br>國防科學研究所<br>90<br>Recently, the technologies of remote sensing are getting more and more sophisticated. The high resolution which remote sensing imagery provided is much better than before and makes these imagey more frequently used in various researches and developments. When considering several important applications, the estimation and classification of multiple materials in a unitary mixed pixel is the major challenge. The correctness of the estimation and classification depends on the background knowledge of the imagery themself which we can refer to. Especially, when the background is unknown or blind, the estimation and classification of the remote sensing imagery is quite a difficult task. In this dissertation, three new methods are proposed to deal with the problems of estimation and classification in remote sensing imagery for subpixel detection and feature extraction. They are Similarity-Histogram based Semi-Thresholding (SHST), Noise-Adjusted Transformed Gerschgorin Disk (NATGD), and Spectral Data Explorer (SDE). The SHST adopts the orthogonal subspace projection technique by projecting the object and noise into complement spaces. Then, the concept of similarity is used to evaluate these spaces and forms a histogram from similarity values. The appropriate threshold value of histogram extract the object features is therefore determined through the histogram distribution. The NATGD is designed to estimate the abundance in the mixed pixel of hyperspectral imagery. The advantage of the method is that NATGD can still judge the object from noise even the background noise is unknown. Finally, the SDE is a hybrid technology combing the Fast Independent Component Analysis (FastICA) and the Noise-adjust Principal Component Analysis (NAPCA) together. Using the method of SDE, the important target information can be extracted from the hyperspectral imagery under unknown background environment successfully.