During the past few years, potentially misdirected effort has been expended developing the notion of high definition television (HDTV) as a system akin to existing television but with approximately twice the spatial resolution horizontally and vertically, and with a slightly higher aspect ratio. System proponents have suggested “production” or distribution systems where the sole difference between current systems and these new ideas is the number of lines and the pixel rate. These efforts have resulted in international discord that may well result in a generation of television systems that impede international interchange of programs, fail to deliver higher quality to the consumer, and retard the technological convergence of computer workstation technology with that of consumer video. In this paper, we suggest that HDTV is an issue of system architecture rather than line count, and we explore signal representations that allow for multiple, simultaneous display of disparate TV standards on the same screen. The notions presented here are not fully developed but are fruitful areas of research and study. We suggest that a new generation of television systems be predicated upon sequential component representation of the video sequence rather than a series of frames and that consumer receivers and workstations be optimized for processing this video format.
{"title":"Open Architecture Television","authors":"V. Bove, A. Lippman","doi":"10.5594/M00916","DOIUrl":"https://doi.org/10.5594/M00916","url":null,"abstract":"During the past few years, potentially misdirected effort has been expended developing the notion of high definition television (HDTV) as a system akin to existing television but with approximately twice the spatial resolution horizontally and vertically, and with a slightly higher aspect ratio. System proponents have suggested “production” or distribution systems where the sole difference between current systems and these new ideas is the number of lines and the pixel rate. These efforts have resulted in international discord that may well result in a generation of television systems that impede international interchange of programs, fail to deliver higher quality to the consumer, and retard the technological convergence of computer workstation technology with that of consumer video. In this paper, we suggest that HDTV is an issue of system architecture rather than line count, and we explore signal representations that allow for multiple, simultaneous display of disparate TV standards on the same screen. The notions presented here are not fully developed but are fruitful areas of research and study. We suggest that a new generation of television systems be predicated upon sequential component representation of the video sequence rather than a series of frames and that consumer receivers and workstations be optimized for processing this video format.","PeriodicalId":344719,"journal":{"name":"Applied Vision","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131074296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
After a short survey of some other measures of perceived image quality, the recently proposed square root integral (SQRI) is described, with special attention to the way in which this measure takes the effect of various display parameters into account. Experimental data on subjective image quality at varying resolution, addressability, contrast, luminance and display size are compared with predictions by the square root Integral. From the comparison it appears that there is a high correlation between perceived image quality and calculated SQRI value.
{"title":"Evaluation of Subjective Image Quality with the Square Root Integral Method","authors":"P. Barten","doi":"10.1364/JOSAA.7.002024","DOIUrl":"https://doi.org/10.1364/JOSAA.7.002024","url":null,"abstract":"After a short survey of some other measures of perceived image quality, the recently proposed square root integral (SQRI) is described, with special attention to the way in which this measure takes the effect of various display parameters into account.\u0000 Experimental data on subjective image quality at varying resolution, addressability, contrast, luminance and display size are compared with predictions by the square root Integral. From the comparison it appears that there is a high correlation between perceived image quality and calculated SQRI value.","PeriodicalId":344719,"journal":{"name":"Applied Vision","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116383031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Use of the CSF in Image Compression The visual system’s variations in sensitivity to spatial frequencies are critical to any imaging system where the image is to be displayed and viewed by a human observer. These variations are described by the contrast sensitivity function (CSF) which has found wide application in image compression schemes using the discrete cosine transform (DCT) [1-3], vector quantization [4], and spatial filter hierarchies [5]. All of these approaches provide access to the frequency domain, and the use of the CSF becomes straightforward in controlling the quantization process of the algorithm. Quantization is used to code the algorithm coefficients or vectors; an increase in the size of the quantization interval reduces the entropy, and thus the bit rate. However, larger quantization intervals increase the quantization error of the algorithm, which can be regarded as noise that will degrade the image if it is visible. This quantization noise must be detected in the presence of the effective internal noise of the visual system, which is proportional to the inverse of the CSF. Therefore, the inverse CSF can be used to scale the quantization intervals, allowing larger intervals for frequencies where the visual system is less sensitive and smaller intervals where it is more sensitive. If, for all frequencies, the maximum error of the frequency specific quantization noise is kept less than the effective internal noise of the frequency, the compressed image will be visually indistinguishable from the uncompressed image. We refer to this condition as perceptually lossless, as opposed to mathematically lossless, in which the digital code values are exactly preserved. Since the bit rates for perceptually lossless compression are less than a quarter of those for mathematically lossless compression, perceptually lossless compression is a useful criterion when the image is to be viewed by human observers.
{"title":"Image Compression in Noise","authors":"S. Daly","doi":"10.1364/av.1989.wd5","DOIUrl":"https://doi.org/10.1364/av.1989.wd5","url":null,"abstract":"Use of the CSF in Image Compression The visual system’s variations in sensitivity to spatial frequencies are critical to any imaging system where the image is to be displayed and viewed by a human observer. These variations are described by the contrast sensitivity function (CSF) which has found wide application in image compression schemes using the discrete cosine transform (DCT) [1-3], vector quantization [4], and spatial filter hierarchies [5]. All of these approaches provide access to the frequency domain, and the use of the CSF becomes straightforward in controlling the quantization process of the algorithm. Quantization is used to code the algorithm coefficients or vectors; an increase in the size of the quantization interval reduces the entropy, and thus the bit rate. However, larger quantization intervals increase the quantization error of the algorithm, which can be regarded as noise that will degrade the image if it is visible. This quantization noise must be detected in the presence of the effective internal noise of the visual system, which is proportional to the inverse of the CSF. Therefore, the inverse CSF can be used to scale the quantization intervals, allowing larger intervals for frequencies where the visual system is less sensitive and smaller intervals where it is more sensitive. If, for all frequencies, the maximum error of the frequency specific quantization noise is kept less than the effective internal noise of the frequency, the compressed image will be visually indistinguishable from the uncompressed image. We refer to this condition as perceptually lossless, as opposed to mathematically lossless, in which the digital code values are exactly preserved. Since the bit rates for perceptually lossless compression are less than a quarter of those for mathematically lossless compression, perceptually lossless compression is a useful criterion when the image is to be viewed by human observers.","PeriodicalId":344719,"journal":{"name":"Applied Vision","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127464266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The use of a human visual model based distortion measure for image coding and evaluation is described. Test results show that when an image is encoded using the visual model, the measured quality correlates better with visual quality when the measurements are made within the model, and better images are produced.
{"title":"Distortion Metrics for Image Coding Using Monochrome and Color Human Visual Models","authors":"S. Budge","doi":"10.1364/av.1989.tha6","DOIUrl":"https://doi.org/10.1364/av.1989.tha6","url":null,"abstract":"The use of a human visual model based distortion measure for image coding and evaluation is described. Test results show that when an image is encoded using the visual model, the measured quality correlates better with visual quality when the measurements are made within the model, and better images are produced.","PeriodicalId":344719,"journal":{"name":"Applied Vision","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122444408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recently, Ahumada and Yellott (1) and Maloney (5,6) have presented schemes for training networks designed to reconstruct irregularly sampled retinal images. In these schemes adjustable weighting networks provide compensation for the irregularities in the retinal array and the geometrical distortions in intermediate pathways. This paper presents some ideas relating to the convergence of the training algorithms.
{"title":"Learning in Interpolation Networks for Irregular Sampling: Some Convergence Properties","authors":"A. Ahumada, J. Mulligan","doi":"10.1364/av.1989.wc3","DOIUrl":"https://doi.org/10.1364/av.1989.wc3","url":null,"abstract":"Recently, Ahumada and Yellott (1) and Maloney (5,6) have presented schemes for training networks designed to reconstruct irregularly sampled retinal images. In these schemes adjustable weighting networks provide compensation for the irregularities in the retinal array and the geometrical distortions in intermediate pathways. This paper presents some ideas relating to the convergence of the training algorithms.","PeriodicalId":344719,"journal":{"name":"Applied Vision","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116846170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Spatial imagery is represented in the brain in the responses of populations of neurons, or neural codes. The use of digital implementations of these neural codes to evaluate image fidelity will be discussed.
{"title":"Neural Codes, Receptive Fields, and Visual Represenations","authors":"A. Watson","doi":"10.1364/av.1989.wb1","DOIUrl":"https://doi.org/10.1364/av.1989.wb1","url":null,"abstract":"Spatial imagery is represented in the brain in the responses of populations of neurons, or neural codes. The use of digital implementations of these neural codes to evaluate image fidelity will be discussed.","PeriodicalId":344719,"journal":{"name":"Applied Vision","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116481839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We discuss the significance of perceptual effects for source coding of video signals without visible impairments. A new nonlinear spatiotemporal model of human threshold vision is proposed. Linearization yields the space-time-varying w-model. The model predicts a variety of perceptual effects accurately. Maximum bit-rate savings by irrelevancy reduction according to the w-model are evaluated for natural test pictures on the basis of the Shannon Lower Bound of rate distortion theory. Under typical viewing conditions, perceptual gains due to linear effects dominate. Maximum bit-rate savings due to the nonlinear masking effects are below 0.5 bit/sample in the average. Typically ⅓ of the masking gain is due to spatial masking, the rest is due to the presence of dark and bright areas in the picture, where the visibility of noise is reduced. Gains due to temporal masking are significant only in the first 100 ms after a scene cut.
{"title":"Perceptual Gains for Coding of Moving Images without Visible Impairments","authors":"B. Girod","doi":"10.1364/av.1989.tha8","DOIUrl":"https://doi.org/10.1364/av.1989.tha8","url":null,"abstract":"We discuss the significance of perceptual effects for source coding of video signals without visible impairments. A new nonlinear spatiotemporal model of human threshold vision is proposed. Linearization yields the space-time-varying w-model. The model predicts a variety of perceptual effects accurately. Maximum bit-rate savings by irrelevancy reduction according to the w-model are evaluated for natural test pictures on the basis of the Shannon Lower Bound of rate distortion theory. Under typical viewing conditions, perceptual gains due to linear effects dominate. Maximum bit-rate savings due to the nonlinear masking effects are below 0.5 bit/sample in the average. Typically ⅓ of the masking gain is due to spatial masking, the rest is due to the presence of dark and bright areas in the picture, where the visibility of noise is reduced. Gains due to temporal masking are significant only in the first 100 ms after a scene cut.","PeriodicalId":344719,"journal":{"name":"Applied Vision","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130698242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A relatively new theory of human visual processing, called Intensity-Dependent Spread (IDS), has some interesting properties as a digital image processing algorithm.
{"title":"Image Processing by Intensity-Dependent Spread","authors":"T. Cornsweet, J. Yellott","doi":"10.1364/av.1989.wd2","DOIUrl":"https://doi.org/10.1364/av.1989.wd2","url":null,"abstract":"A relatively new theory of human visual processing, called Intensity-Dependent Spread (IDS), has some interesting properties as a digital image processing algorithm.","PeriodicalId":344719,"journal":{"name":"Applied Vision","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114854541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Suppose that we wish to compare the color appearance of an image displayed on monitor and a reproduction of the image on a printed page. We could place the monitor and printed image side-by-side and let an observer judge the colors of each. The difficulty with this arrangement is that the ambient illumination interferes with the color appearance of the monitor image. To see the monitor image clearly, the observer would like to turn down the room lighting. But in this case, the observer will be unable to see the printed image. As the room lights are turned up, the printed image becomes visible but the monitor image becomes washed out.
{"title":"Towards cross-media color reproduction","authors":"B. Wandell, D. Brainard","doi":"10.1364/av.1989.fa2","DOIUrl":"https://doi.org/10.1364/av.1989.fa2","url":null,"abstract":"Suppose that we wish to compare the color appearance of an image displayed on monitor and a reproduction of the image on a printed page. We could place the monitor and printed image side-by-side and let an observer judge the colors of each. The difficulty with this arrangement is that the ambient illumination interferes with the color appearance of the monitor image. To see the monitor image clearly, the observer would like to turn down the room lighting. But in this case, the observer will be unable to see the printed image. As the room lights are turned up, the printed image becomes visible but the monitor image becomes washed out.","PeriodicalId":344719,"journal":{"name":"Applied Vision","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116936788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reading is a complex everyday task. Successful reading requires high-speed visual information processing. For several years, my colleagues and I have been studying visual factors in reading with two major goals in mind: to understand the roles played by sensory mechanisms in reading and to understand how visual impairment affects reading. In a typical study, we examine the effect of an important text variable (e.g. contrast) on reading by people with normal vision. Taking the normal data as a bench mark, we try to explain abnormalities in the performance of low-vision subjects.
{"title":"Reading: Effects of Contrast and Spatial Frequency1","authors":"G. Legge","doi":"10.1364/av.1989.thb1","DOIUrl":"https://doi.org/10.1364/av.1989.thb1","url":null,"abstract":"\u0000 Reading\u0000 is a complex everyday task. Successful reading requires high-speed visual information processing. For several years, my colleagues and I have been studying visual factors in reading with two major goals in mind: to understand the roles played by sensory mechanisms in reading and to understand how visual impairment affects reading. In a typical study, we examine the effect of an important text variable (e.g. contrast) on reading by people with normal vision. Taking the normal data as a bench mark, we try to explain abnormalities in the performance of low-vision subjects.","PeriodicalId":344719,"journal":{"name":"Applied Vision","volume":"254 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117315814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：