Feature weighting and retrieval methods for dynamic texture motion features

Feature weighing methods are commonly used to find the relative significance among a set of features that are effectively used by the retrieval methods to search image sequences efficiently from large databases. As evidenced in the current literature, dynamic textures (image sequences with regular motion patterns) can be effectively modelled by a set of spatial and temporal motion distribution features like motion co-occurrence matrix. The aim of this paper is to develop effective feature weighting and retrieval methods for a set of dynamic textures while characterized by motion co-occurrence matrices

Quantifying Texture Scale in Accordance With Human Perception

Visual texture has multiple perceptual attributes (e.g. regularity, isotropy, etc.), including scale. The scale of visual texture has been defined as the size of the repeating unit (or texel) of which the texture is composed. Not all textures are formed through the placement of a clearly discernible repeating unit (e.g. irregular and stochastic textures). There is currently no rigorous definition for texture scale that is applicable to textures of a wide range of regularities. We hypothesised that texture scale ought to extend to these less regular textures. Non-overlapping sample windows (or patches) taken from a texture appear increasingly similar as the size of the window gets larger. This is true irrespective of whether the texture is formed by the placement of a discernible repeating unit or not. We propose the following new characterisation for texture scale: “the smallest window size beyond within which texture appears consistently”. We perform two psychophysical studies and report data that demonstrates consensus across subjects and across methods of probing in the assessment of texture scale. We then present an empirical algorithm for the estimation of scale based on this characterisation. We demonstrate agreement between the algorithm and (subjective) human assessment with an RMS accuracy of 1.2 just-noticeable-differences, a significant improvement over previous published algorithms. We provide two ground-truth perceptual datasets, one for each of our psychophysical studies, for the texture scale of the entire Brodatz album, together with confidence levels for each of our estimates. Finally, we make available an online tool which researchers can use to obtain texture scale estimates by uploading images of textures

Analysis and performance evaluation of optical flow features for dynamic texture recognition

We address the problem of dynamic texture (DT) classification using optical flow features. optical flow based approaches dominate among the currently available DT classification methods. The features used by these approaches often describe local image distortions in terms of such quantities as curl or divergence. Both normal and complete flows have been considered, with normal flow being used more frequently. However, precise meaning and applicability of normal and complete flow features have never been analysed properly. We provide a principled analysis of local image distortions and their relation to optical flow. Then we present the results of a comprehensive DT classification study that compares the performances of different flow features for a normal flow algorithm and four different complete flow algorithms. The efficiencies of two flow confidence measures are also studied

Analysis and performance evaluation of optical flow features for dynamic texture recognition

We address the problem of dynamic texture (DT) classification using optical flow features. optical flow based approaches dominate among the currently available DT classification methods. The features used by these approaches often describe local image distortions in terms of such quantities as curl or divergence. Both normal and complete flows have been considered, with normal flow being used more frequently. However, precise meaning and applicability of normal and complete flow features have never been analysed properly. We provide a principled analysis of local image distortions and their relation to optical flow. Then we present the results of a comprehensive DT classification study that compares the performances of different flow features for a normal flow algorithm and four different complete flow algorithms. The efficiencies of two flow confidence measures are also studied