Journal ArticleDOI
Contrast in complex images.
TLDR
A definition of local band-limited contrast in images is proposed that assigns a contrast value to every point in the image as a function of the spatial frequency band and is helpful in understanding the effects of image-processing algorithms on the perceived contrast.Abstract:
The physical contrast of simple images such as sinusoidal gratings or a single patch of light on a uniform background is well defined and agrees with the perceived contrast, but this is not so for complex images. Most definitions assign a single contrast value to the whole image, but perceived contrast may vary greatly across the image. Human contrast sensitivity is a function of spatial frequency; therefore the spatial frequency content of an image should be considered in the definition of contrast. In this paper a definition of local band-limited contrast in images is proposed that assigns a contrast value to every point in the image as a function of the spatial frequency band. For each frequency band, the contrast is defined as the ratio of the bandpass-filtered image at the frequency to the low-pass image filtered to an octave below the same frequency (local luminance mean). This definition raises important implications regarding the perception of contrast in complex images and is helpful in understanding the effects of image-processing algorithms on the perceived contrast. A pyramidal image-contrast structure based on this definition is useful in simulating nonlinear, threshold characteristics of spatial vision in both normal observers and the visually impaired.read more
Citations
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Proceedings ArticleDOI
Photographic tone reproduction for digital images
TL;DR: The work presented in this paper leverages the time-tested techniques of photographic practice to develop a new tone reproduction operator and uses and extends the techniques developed by Ansel Adams to deal with digital images.
Journal ArticleDOI
Information Content Weighting for Perceptual Image Quality Assessment
Zhou Wang,Qiang Li +1 more
TL;DR: This paper aims to test the hypothesis that when viewing natural images, the optimal perceptual weights for pooling should be proportional to local information content, which can be estimated in units of bit using advanced statistical models of natural images.
Book
Modern image quality assessment
Zhou Wang,A.C. Bovik +1 more
TL;DR: This book is about objective image quality assessment to provide computational models that can automatically predict perceptual image quality and to provide new directions for future research by introducing recent models and paradigms that significantly differ from those used in the past.
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Perceptual visual quality metrics: A survey
Weisi Lin,C.-C. Jay Kuo +1 more
TL;DR: A systematic, comprehensive and up-to-date review of perceptual visual quality metrics (PVQMs) to predict picture quality according to human perception.
Journal ArticleDOI
Image quality assessment based on a degradation model
TL;DR: It is demonstrated how to decouple distortion and additive noise degradation in a practical image restoration system and the nonlinear NQM is a better measure of visual quality than peak signal-to noise ratio (PSNR) and linear quality measures.
References
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Proceedings ArticleDOI
Pyramidal Normalization Filter: Visual Model With Applications To Image Understanding
TL;DR: A highly efficient and flexible realization of the normalization filter based on Burt's algorithm for pyramidal filtering is described, which is the basis for non-directional, multiple spatial frequency channel resolved detection of image edge structure.