299 research outputs found
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Method and apparatus for processing both still and moving visual pattern images
An improved method for coding and decoding still or moving visual pattern images by partitioning images into blocks or cubes, respectively, and coding each image separately according to visually significant responses of the human eye. Coding is achieved by calculating and subtracting a mean intensity value from digital numbers within each block or cube and detecting visually perceivable edge locations within the resultant residual sub-image. If a visually perceivable edge is contained within the block or cube, gradient magnitude and orientation at opposing sides of the edge within each edge block or cube are calculated and appropriately coded. If no perceivable edge is contained within the block or cube, the sub-image is coded as a uniform intensity block. Decoding requires receiving coded mean intensity value, gradient magnitude and pattern code, and then decoding a combination of these three indicia to be arranged in an orientation substantially similar to the original digital image or original sequence of digital images. Coding and decoding can be accomplished in a hierarchical pattern. Further, hierarchical processing can be programmably manipulated according to user-defined criteria.Board of Regents, University of Texas Syste
Quality Modeling Under A Relaxed Natural Scene Statistics Model
Information-theoretic image quality assessment (IQA) models such as Visual
Information Fidelity (VIF) and Spatio-temporal Reduced Reference Entropic
Differences (ST-RRED) have enjoyed great success by seamlessly integrating
natural scene statistics (NSS) with information theory. The Gaussian Scale
Mixture (GSM) model that governs the wavelet subband coefficients of natural
images forms the foundation for these algorithms. However, the explosion of
user-generated content on social media, which is typically distorted by one or
more of many possible unknown impairments, has revealed the limitations of
NSS-based IQA models that rely on the simple GSM model. Here, we seek to
elaborate the VIF index by deriving useful properties of the Multivariate
Generalized Gaussian Distribution (MGGD), and using them to study the behavior
of VIF under a Generalized GSM (GGSM) model
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