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Journal articles on the topic 'Spatial frequencie'

Author: Grafiati

Published: 9 March 2023

Last updated: 31 July 2025

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1

Zhang Zhe, 张喆, 郑东晖 Zheng Donghui, 陈磊 Chen Lei та 李金鹏 Li Jinpeng. "低空间频率干涉条纹的载频计算方法". Acta Optica Sinica 44, № 4 (2024): 0412005. http://dx.doi.org/10.3788/aos231718.

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2

Pankil Butala, Pankil Butala, Hany Elgala Hany Elgala, and Thomas D. C. Little Thomas D. C. Little. "Sample indexed spatial orthogonal frequency division multiplexing." Chinese Optics Letters 12, no. 9 (2014): 090602–90606. http://dx.doi.org/10.3788/col201412.090602.

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3

ICHIHARA, SHIGERU. "Perceived spatial frequency shift after adaptation to compound gratings of two sinusoidals in phase or 180° out of phase." Japanese Psychological Research 29, no. 1 (1987): 10–16. http://dx.doi.org/10.4992/psycholres1954.29.10.

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4

Lee, Jeunghoon, Yongsung Park, and Peter Gerstoft. "Generalized frequency-sum beamforming for low frequencies." Journal of the Acoustical Society of America 156, no. 6 (2024): 4037–47. https://doi.org/10.1121/10.0034621.

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For direction-of-arrival (DOA) estimation in the low-frequency range, we improve spatial resolution using generalized frequency-sum (gFS) beamforming with the Qth order frequency-sum autoproduct. The order Q does not exceed the maximum value, determined by the criteria that the sum of frequencies used to create the autoproduct must be less than the array's spatial Nyquist frequency. Unlike other high-resolution beamformers, gFS maintains stable performance even with a single snapshot and is unaffected by the coherence of steering vectors. Rigorous analysis using the multinomial expansion has s

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5

Pohl, M., and R. Börret. "Simulation of mid-spatials from the grinding process." Journal of the European Optical Society-Rapid Publications 11 (2016): 16010. https://doi.org/10.1051/jeos.2016.16010.

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This paper focuses on the simulation of the creation of mid-spatial frequencies (mid-spatials) during the grinding process of optical components. The goal is to simulate this generation process and determine the correlating grinding parameters for mid-spatials. On this base, grinding parameters which lead to less mid-spatials could be determined.

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6

Stancă Ionut, Rizea Ileana Olguta, Popescu Andreea Caterina, Albu Alice, Rus Mihaela, and Fica Simona. "The importance of cardiac tomography in the evaluation of cardiac changes and coronary atherosclerosis in patients with betathalassemia major." Technium Social Sciences Journal 11 (September 14, 2020): 602–11. http://dx.doi.org/10.47577/tssj.v11i1.1677.

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Betathalassemic patients demonstrate an increased rate of extracardiac vascular complications, but very low prevalence for coronary artery disease. Computed tomography (CT) achieves excellent tissue characterization, with high spatial resolution and has developed as a gold standard for noninvasive angiography and calcium score assessment. Methods. We examined 7 patients with major beta-thalassemia and 7 patients who had an indication for cardiac CT for resting ECG changes, without symptoms of angina pectoris. We investigated the coronary atherosclerosis by assessing the coronary artery calcium

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7

Zhou, Y. X., and C. L. Baker. "Spatial properties of envelope-responsive cells in area 17 and 18 neurons of the cat." Journal of Neurophysiology 75, no. 3 (1996): 1038–50. http://dx.doi.org/10.1152/jn.1996.75.3.1038.

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1. Many neurons in areas 17 and 18 respond to spatial contrast envelope stimuli whose Fourier components fall outside the cell's spatial-frequency-selective range. The spatial properties of such envelope responses are investigated here and compared with responses to conventional luminance-defined gratings to explore the underlying receptive-field mechanism. 2. Three spatial properties of envelope responses are reported more extensively in this paper. First, the envelope responses were selective to the carrier spatial frequency in a narrow range of frequencies higher than a given cell's luminan

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8

Sagi, Dov, and Shaul Hochstein. "Lateral inhibition between spatially adjacent spatial-frequency channels?" Perception & Psychophysics 37, no. 4 (1985): 315–22. http://dx.doi.org/10.3758/bf03211354.

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9

COHEN, LEON. "Time-Frequency Spatial-Spatial Frequency Representations." Annals of the New York Academy of Sciences 808, no. 1 Nonlinear Sig (1997): 97–115. http://dx.doi.org/10.1111/j.1749-6632.1997.tb51655.x.

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10

Shi Zhiguo, 石志国, 张洋 Zhang Yang, 王全福 Wang Quanfu та ін. "偏振空间频域成像系统及仿体验证". Chinese Journal of Lasers 50, № 9 (2023): 0907104. http://dx.doi.org/10.3788/cjl221483.

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11

Dev, Ashwani, and George A. McMechan. "Spatial antialias filtering in the slowness-frequency domain." GEOPHYSICS 74, no. 2 (2009): V35—V42. http://dx.doi.org/10.1190/1.3052115.

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A rigorous, explicit spatial antialias filter is designed and applied to spatially coarsely sampled seismic data by removing all energy above the first Nyquist wavenumber, and aliased energy that is folded back across the Nyquist, in the horizontal slowness-frequency domain. The spatial filtering in the slowness-frequency domain is explicit, free from any event linearity assumption, and does not require any interpolation. The spatially aliased energy is dispersive, and present at small and large slownesses. Comparison of the output data after antialias spatial filtering, with output data after

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12

Pigliucci, Massimo, and Guido Barbujani. "Geographical patterns of gene frequencies in Italian populations of Ornithogalum montanum (Liliaceae)." Genetical Research 58, no. 2 (1991): 95–104. http://dx.doi.org/10.1017/s0016672300029736.

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SummaryGeographic variation was studied at 15 electrophoretic loci (40 alleles) in Italian populations of Ornithogalum montanum Cyr. ex Ten. (Liliaceae). Homogeneity of allele frequencies was assessed by G tests; gene-frequency patterns were described by spatial autocorrelation statistics; matrices of genetic and environmental distance were compared through a series of Mantel's tests, and the zones of highest overall gene-frequency change per unit distance (steep multi-locus clines, or genetic boundaries) were identified. Nineteen allele frequencies appear heterogeneously distributed, but only

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13

Mayer, Melanie J., and Charlene B. Y. Kim. "Smooth frequency discrimination functions for foveal, high-contrast, mid spatial frequencies." Journal of the Optical Society of America A 3, no. 11 (1986): 1957. http://dx.doi.org/10.1364/josaa.3.001957.

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14

Dan Mai, 但迈, 刘美慧 Liu Meihui та 高峰 Gao Feng. "单像素空间频域成像的实时化". Chinese Journal of Lasers 49, № 5 (2022): 0507207. http://dx.doi.org/10.3788/cjl202249.0507207.

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15

Shulman, Gordon L., and James Wilson. "Spatial Frequency and Selective Attention to Spatial Location." Perception 16, no. 1 (1987): 103–11. http://dx.doi.org/10.1068/p160103.

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The effect of spatial attention on the detectability of gratings of different spatial frequency was measured using a probe technique. Three experiments are reported in which the detectability of full-field probe gratings was measured while subjects analyzed stimuli presented in either the central or the peripheral visual field. Selective attention to peripheral stimuli produced a facilitation at low frequencies and a decrement at high frequencies. These effects disappeared under forced-choice presentation.

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16

Bensmaïa, S. J., J. C. Craig, and K. O. Johnson. "Temporal Factors in Tactile Spatial Acuity: Evidence for RA Interference in Fine Spatial Processing." Journal of Neurophysiology 95, no. 3 (2006): 1783–91. http://dx.doi.org/10.1152/jn.00878.2005.

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We investigated the extent to which subjects’ ability to perceive the fine spatial structure of a stimulus depends on its temporal properties (namely the frequency at which it vibrates). Subjects were presented with static or vibrating gratings that varied in spatial period (1–8 mm) and vibratory frequency (5–80 Hz) and judged the orientation of the gratings, presented either parallel or perpendicular to the long axis of the finger. We found that the grating orientation threshold (GOT)—the spatial period at which subjects can reliably discriminate the orientation of the grating—increased as th

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17

Baro, John A., and Stephen Lehmkuhle. "The effects of a luminanace-modulated background on the grating-evoked cortical potential in the cat." Visual Neuroscience 3, no. 6 (1989): 563–72. http://dx.doi.org/10.1017/s0952523800009895.

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AbstractAveraged grating-evoked cortical potentials were recorded from area 17 of awake cats. Peak latency of early components of the visual-evoked potential (VEP) response to stimulus onset increased as a function of spatial frequency, while amplitude tended to be largest at intermediate spatial frequencies. Latency increased and amplitude generally decreased to lower spatial-frequency stimuli (<0.25 cycle/deg) in the presence of a uniform flickering field (UFF). The UFF had a relatively small or opposite effect on peak latency and amplitude for higher spatial-frequency stimuli (>0.50 c

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18

Bosen, Adam K., Peter A. Wasiuk, Lauren Calandruccio, and Emily Buss. "Frequency importance for sentence recognition in co-located noise, co-located speech, and spatially separated speech." Journal of the Acoustical Society of America 156, no. 5 (2024): 3275–84. http://dx.doi.org/10.1121/10.0034412.

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Frequency importance functions quantify the contribution of spectral frequencies to perception. Frequency importance has been well-characterized for speech recognition in quiet and steady-state noise. However, it is currently unknown whether frequency importance estimates generalize to more complex conditions such as listening in a multi-talker masker or when targets and maskers are spatially separated. Here, frequency importance was estimated by quantifying associations between local target-to-masker ratios at the output of an auditory filterbank and keyword recognition accuracy for sentences

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19

Yin, Ling Xiao, and Jing Ling Chen. "Spin Spatial Frequency Response of Atomic Magnetometer." Key Engineering Materials 787 (November 2018): 81–86. http://dx.doi.org/10.4028/www.scientific.net/kem.787.81.

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We describe a method for measuring the spin spatial frequency response in a Cs vapor cell by using a digital micro-mirror device (DMD) to modulate the pumping light both spatially and temporally. An equivalent space-alternative magnetic field is created by this way. The pumping light through the Cs vapor cell is measured and analyzed in spatial frequency domain. We obtain the spatial frequency response of the Cs vapor cell from 1.4 cm-1to 364.9 cm-1. The theoretical results of the spatial frequency response according to Fick's second diffusion law agree with the experimental results. This meth

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20

Jacobson, Lowell D., and Harry Wechsler. "Joint spatial/spatial-frequency representation." Signal Processing 14, no. 1 (1988): 37–68. http://dx.doi.org/10.1016/0165-1684(88)90043-6.

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21

Frishman, L. J., A. W. Freeman, J. B. Troy, D. E. Schweitzer-Tong, and C. Enroth-Cugell. "Spatiotemporal frequency responses of cat retinal ganglion cells." Journal of General Physiology 89, no. 4 (1987): 599–628. http://dx.doi.org/10.1085/jgp.89.4.599.

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Spatiotemporal frequency responses were measured at different levels of light adaptation for cat X and Y retinal ganglion cells. Stationary sinusoidal luminance gratings whose contrast was modulated sinusoidally in time or drifting gratings were used as stimuli. Under photopic illumination, when the spatial frequency was held constant at or above its optimum value, an X cell's responsivity was essentially constant as the temporal frequency was changed from 1.5 to 30 Hz. At lower temporal frequencies, responsivity rolled off gradually, and at higher ones it rolled off rapidly. In contrast, when

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22

Hague, Michael T. J., Heidi Mavengere, Daniel R. Matute, and Brandon S. Cooper. "Environmental and Genetic Contributions to Imperfect wMel-Like Wolbachia Transmission and Frequency Variation." Genetics 215, no. 4 (2020): 1117–32. http://dx.doi.org/10.1534/genetics.120.303330.

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Maternally transmitted Wolbachia bacteria infect about half of all insect species. They usually show imperfect maternal transmission and often produce cytoplasmic incompatibility (CI). Irrespective of CI, Wolbachia frequencies tend to increase when rare only if they benefit host fitness. Several Wolbachia, including wMel that infects Drosophila melanogaster, cause weak or no CI and persist at intermediate frequencies. On the island of São Tomé off West Africa, the frequencies of wMel-like Wolbachia infecting Drosophila yakuba (wYak) and Drosophila santomea (wSan) fluctuate, and the contributio

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23

Bilotta, J., and I. Abramov. "Spatial properties of goldfish ganglion cells." Journal of General Physiology 93, no. 6 (1989): 1147–69. http://dx.doi.org/10.1085/jgp.93.6.1147.

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We systematically classified goldfish ganglion cells according to their spatial summation properties using the same techniques and criteria used in cat and monkey research. Results show that goldfish ganglion cells can be classified as X-, Y-, or W-like based on their responses to contrast-reversal gratings. Like cat X cells, goldfish X-like cells display linear spatial summation. Goldfish Y-like cells, like cat Y cells, respond with frequency doubling at all spatial positions when the contrast-reversal grating consists of high spatial frequencies. There is also a third class of neurons, which

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24

Regan, D. "Storage of spatial-frequency information and spatial-frequency discrimination." Journal of the Optical Society of America A 2, no. 4 (1985): 619. http://dx.doi.org/10.1364/josaa.2.000619.

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25

Tootoonian, Sina, Aaron C. True, Elle Stark, John P. Crimaldi, and Andreas T. Schaefer. "Quantifying spectral information about source separation in multisource odour plumes." PLOS ONE 20, no. 1 (2025): e0297754. https://doi.org/10.1371/journal.pone.0297754.

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Odours released by objects in natural environments can contain information about their spatial locations. In particular, the correlation of odour concentration timeseries produced by two spatially separated sources contains information about the distance between the sources. For example, mice are able to distinguish correlated and anti-correlated odour fluctuations at frequencies up to 40 Hz, while insect olfactory receptor neurons can resolve fluctuations exceeding 100 Hz. Can this high-frequency acuity support odour source localization? Here we answer this question by quantifying the spatial

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26

Moraglia, Giampaolo. "Visual Search: Spatial Frequency and Orientation." Perceptual and Motor Skills 69, no. 2 (1989): 675–89. http://dx.doi.org/10.2466/pms.1989.69.2.675.

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Observers searched for a Gaussian-windowed patch of sinewave grating (Gabor pattern) through displays containing varying numbers of other such patterns (distractors). When the spatial frequencies of target and distractors differed by ± 2 octaves and their orientations by ± 60°, the search proceeded spatially in parallel irrespective of whether the target could be discriminated in terms of spatial frequency differences alone, orientation differences alone, or their combination. However, when target and distractors differed by only ±.5 octave in spatial frequency and by ± 15° in orientation, the

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27

Djerir, Wahiba, Tarek Boutkedjirt, Ali Badidi Bouda, and A. Satour. "Application of Inverse Methods for Spatial Deconvolution of Pulsed Ultrasound Fields Radiated in Solids." Materials Science Forum 636-637 (January 2010): 1541–47. http://dx.doi.org/10.4028/www.scientific.net/msf.636-637.1541.

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When measuring the ultrasound field, the signal provided by the receiving transducer is affected by its spatial properties. Particularly, the displacement normal to its surface is spatially averaged because of the receiver finite size. In this study, we show using a numerical simulation, the effectiveness of the spatial deconvolution of these effects for a rectangular transducer. For that, three methods allowing the inversion of the aperture effect are tested 1) Wiener’s method; 2) the power spectral equalization (PSE) method, and 3) the maximum a posteriori (MAP) method. The obtained results

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28

Aiken, Bonnie E., and Michael S. Loop. "Visual reaction time of cats to different spatial frequencies." Visual Neuroscience 5, no. 6 (1990): 557–64. http://dx.doi.org/10.1017/s0952523800000717.

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AbstractIf physiological mechanisms similar to cat Y and X cells explain faster detection of low spatial frequencies by humans, then cats should show the same effect. We have tested this prediction by determining the visual reaction time of cats over a range of spatial frequencies and contrasts by training them to respond quickly when a vertical sine-wave grating was presented. At 50% contrast, the cat's visual reaction time increased monotonically from 0.25–2.0 cpd (cycle/deg). At every spatial frequency tested, the cat's reaction time increased monotonically as contrast decreased. By determi

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29

Schor, Clifton M., and Peter A. Howarth. "Suprathreshold Stereo-Depth Matches as a Function of Contrast and Spatial Frequency." Perception 15, no. 3 (1986): 249–58. http://dx.doi.org/10.1068/p150249.

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Thresholds for stereoscopic-depth perception increase with decreasing spatial frequency below 2.5 cycles deg−1. Despite this variation of stereo threshold, suprathreshold stereoscopic-depth perception is independent of spatial frequency down to 0.5 cycle deg-1. Below this frequency the perceived depth of crossed disparities is less than that stimulated by higher spatial frequencies which subtend the same disparities. We have investigated the effects of contrast fading upon this breakdown of stereo-depth invariance at low spatial frequencies. Suprathreshold stereopsis was investigated with spat

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30

Liu Meihui, 刘美慧, 但迈 Dan Mai та 高峰 Gao Feng. "基于目标形貌测量的空间频域成像校正方法". Laser & Optoelectronics Progress 58, № 10 (2021): 1011027. http://dx.doi.org/10.3788/lop202158.1011027.

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31

Wang Yan, 王岩, та 牛宏伟 Niu Hongwei. "基于光学空频域变换的自适应图像分块隐藏技术". Laser & Optoelectronics Progress 58, № 16 (2021): 1609001. http://dx.doi.org/10.3788/lop202158.1609001.

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32

FAN Yan, 范焱, 刘乔 LIU Qiao, 袁笛 YUAN Di та 刘云鹏 LIU Yunpeng. "空域和频域特征解耦的红外与可见光图像融合". Infrared and Laser Engineering 53, № 8 (2024): 20240198. http://dx.doi.org/10.3788/irla20240198.

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33

Zhong Xiaoxue, 钟晓雪, 黄国武 Huang Guowu, 缪弘波 Miu Hongbo та ін. "基于空间频域成像的烧伤程度无创定量评估". Chinese Journal of Lasers 49, № 24 (2022): 2407205. http://dx.doi.org/10.3788/cjl202249.2407205.

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34

Hou Yue, 侯越, 郝紫微 Hao Ziwei, 张志豪 Zhang Zhihao та 尹杰 Yin Jie. "空间双域高频特征显著化的图像超分辨率重建". Laser & Optoelectronics Progress 62, № 6 (2025): 0637011. https://doi.org/10.3788/lop241598.

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35

Shen Yu, 沈瑜, 白珊 Bai Shan, 魏子易 Wei Ziyi та ін. "基于跨模态感知和空频交叉的医学图像融合". Chinese Journal of Lasers 52, № 9 (2025): 0907106. https://doi.org/10.3788/cjl241333.

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36

Shen Chenfan, 沈晨帆, 杨建敏 Yang Jianmin, 刘威 Liu Wei та ін. "空间频域成像生理监测中温度的影响分析". Chinese Journal of Lasers 52, № 15 (2025): 1507202. https://doi.org/10.3788/cjl241457.

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37

Hirsch, Joy, and Ron Hylton. "Spatial-frequency discrimination at low frequencies: evidence for position quantization by receptive fields." Journal of the Optical Society of America A 2, no. 2 (1985): 128. http://dx.doi.org/10.1364/josaa.2.000128.

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38

Kozhevnikov, E. N., and Y. V. Samoilova. "SPATIALLY MODULATED STRUCTURES IN NEMATIC LIQUID CRYSTAL UNDER OSCILLATORY COUETTE FLOW AT ULTRALOW FREQUENCIES." Vestnik of Samara University. Natural Science Series 18, no. 6 (2017): 113–23. http://dx.doi.org/10.18287/2541-7525-2012-18-6-113-123.

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The distortion of homeotropic structure of nematic liquid crystal under the inﬂuence of periodic shear at ultralow frequencies is theoretically described. It is shown that periodic shear action results in spatially modulated structure in NLC layer. Threshold shear amplitude and spacial periodicity of new molecular orientational structure are found on the base of nonlinear nematic liquid crystal hydrodynamic equations using Galerkin method. Theoretical analysis shows that at low frequencies threshold shear amplitude does not depend on frequency and the spatial period of the order of NLC layer t

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39

Rosli, Yanti, Suzanne M. Bedford, and Ted Maddess. "Low-Spatial-Frequency Channels and the Spatial Frequency-Doubling Illusion." Investigative Opthalmology & Visual Science 50, no. 4 (2009): 1956. http://dx.doi.org/10.1167/iovs.08-1810.

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40

Yager, Dean, and Patricia Kramer. "A model for perceived spatial frequency and spatial frequency discrimination." Vision Research 31, no. 6 (1991): 1067–72. http://dx.doi.org/10.1016/0042-6989(91)90210-v.

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41

Kim, Jin-Young, Hyun-Han Kwon, and Jeong-Yeul Lim. "Development of Hierarchical Bayesian Spatial Regional Frequency Analysis Model Considering Geographical Characteristics." Journal of Korea Water Resources Association 47, no. 5 (2014): 469–82. http://dx.doi.org/10.3741/jkwra.2014.47.5.469.

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42

Nolt, M. J., R. D. Kumbhani, and L. A. Palmer. "Suppression at High Spatial Frequencies in the Lateral Geniculate Nucleus of the Cat." Journal of Neurophysiology 98, no. 3 (2007): 1167–80. http://dx.doi.org/10.1152/jn.01019.2006.

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The spatial weighting functions of both retinal and lateral geniculate nucleus (LGN) X-cell receptive fields have been viewed as the difference of two Gaussians (DOG). We focus on a particular shortcoming of the DOG model, that is, suppression of responses of LGN cells at spatial frequencies above those to which the classical receptive field surround is responsive. By simultaneously recording one of the retinal ganglion cell (RGC) inputs (S-potentials) to an LGN cell, we find that half of this suppression at high spatial frequencies arises from the retinal input and that suppression in LGN cel

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43

Parish, David H., and George Sperling. "Object spatial frequencies, retinal spatial frequencies, noise, and the efficiency of letter discrimination." Vision Research 31, no. 7-8 (1991): 1399–415. http://dx.doi.org/10.1016/0042-6989(91)90060-i.

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44

Babenko, V. V. "Spatial Extent of Masking by Sine-Wave Gratings." Perception 26, no. 1_suppl (1997): 74. http://dx.doi.org/10.1068/v970219.

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The contrast threshold for detection of a target consisting of 1.5 periods of a sine wave was determined as a function of the number of cycles in a sinusoidal mask with the same spatial frequency and orientation. The test frequencies were 2, 4, and 8 cycles deg−1. The masks were spatial-frequency modulated so as to equate their spectral extent. Stimuli were seen monocularly in Maxwellian view at a mean luminance of 10 cd m−2. The contrast threshold in a backward masking paradigm was determined by a 2AFC staircase. Data were obtained from three subjects with normal vision. It was found that as

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45

Bex, P. J., F. A. J. Verstraten, and I. Mareschal. "Temporal and Spatial Frequency Tuning of the Flicker Motion Aftereffect." Perception 25, no. 1_suppl (1996): 12. http://dx.doi.org/10.1068/v96l0804.

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The motion aftereffect (MAE) was used to study the temporal-frequency and spatial-frequency selectivity of the visual system at suprathreshold contrasts. Observers adapted to drifting sine-wave gratings of a range of spatial and temporal frequencies. The magnitude of the MAE induced by the adaptation was measured with counterphasing test gratings of a variety of spatial and temporal frequencies. Independently of the spatial or temporal frequency of the adapting grating, the largest MAE was found with slowly counterphasing test gratings (∼0.125 – 0.25 Hz). For slowly counterphasing test grating

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46

Morgan, M. J., and R. M. Ward. "Spatial and spatial-frequency primitives in spatial-interval discrimination." Journal of the Optical Society of America A 2, no. 7 (1985): 1205. http://dx.doi.org/10.1364/josaa.2.001205.

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47

Friedl, Wendel M., and Andreas Keil. "Effects of Experience on Spatial Frequency Tuning in the Visual System: Behavioral, Visuocortical, and Alpha-band Responses." Journal of Cognitive Neuroscience 32, no. 6 (2020): 1153–69. http://dx.doi.org/10.1162/jocn_a_01524.

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Using electrophysiology and a classic fear conditioning paradigm, this work examined adaptive visuocortical changes in spatial frequency tuning in a sample of 50 undergraduate students. High-density EEG was recorded while participants viewed 400 total trials of individually presented Gabor patches of 10 different spatial frequencies. Patches were flickered to produce sweep steady-state visual evoked potentials (ssVEPs) at a temporal frequency of 13.33 Hz, with stimulus contrast ramping up from 0% to 41% Michelson over the course of each 2800-msec trial. During the final 200 trials, a selected

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48

Kankaanpää, M. I., J. Rovamo, H. T. Kukkonen, and J. Hallikainen. "Spatial Integration of Objectively Equiluminous Chromatic Gratings." Perception 26, no. 1_suppl (1997): 200. http://dx.doi.org/10.1068/v970297.

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Contrast sensitivity functions for achromatic and chromatic gratings tend to be band-pass and low-pass in shape, respectively. Our aim was to test whether spatial integration contributes to the shape difference found at low spatial frequencies. We measured binocular chromatic contrast sensitivity as a function of grating area for objectively equiluminous red - green and blue - yellow chromatic gratings. Chromatic contrast refers to the Michelson contrast of either of the two chromatic component gratings presented in counterphase against the combined background. Grating area ( A) varied from 1

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Frye, J. Michael, and Anthony Q. Martin. "Wideband Extrapolation of Spatial Responses of Resonant Structures Using Early-Time and Low-Frequency Data." Journal of Computational Methods in Physics 2013 (October 22, 2013): 1–12. http://dx.doi.org/10.1155/2013/563724.

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An efficient procedure is presented to extrapolate a wideband electromagnetic response defined over an arbitrary spatial region using early-time and low-frequency data. The previous procedures presented in the literature are efficient for single-point extrapolation and can readily be applied to spatial regions but are terribly inefficient when a response is desired at many spatial locations. In this work, an optimized algorithm is presented to quickly extrapolate over a large number of spatial locations. The time and frequency behavior of the response is fitted by polynomials and pole terms, a

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Lee, Jeung-Hoon, Yongsung Park, and Peter Gerstoft. "Compressive frequency-difference direction-of-arrival estimation." Journal of the Acoustical Society of America 154, no. 1 (2023): 141–51. http://dx.doi.org/10.1121/10.0020053.

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Direction-of-arrival estimation is difficult for signals spatially undersampled by more than half the wavelength. Frequency-difference beamforming [Abadi, Song, and Dowling (2012). J. Acoust. Soc. Am. 132, 3018–3029] offers an alternative approach to avoid such spatial aliasing by using multifrequency signals and processing them at a lower frequency, the difference-frequency. As with the conventional beamforming method, lowering the processing frequency sacrifices spatial resolution due to a beam broadening. Thus, unconventional beamforming is detrimental to the ability to distinguish between

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