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Patterns in Nature and Human Visual Perception by Ann Hermundstad
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- 1 INTERNATIONAL CENTRE for
- 2 Ann M Hermundstad
- 3 Putters in nature and
- 4 Patterns in nature and human visual perception
- 5 natural stimuli involve many patterns of light that have complex correlational structure...
- 6 to what correlations should we be most sensitive?
- 7 we choose to work in a space of local binary patterns
- 8 binary texture space is fully-described up to fourth-order by 10 independent coordinates
- 9 we reprocess an ensemble of natural images patches
- 10 we reprocess an ensemble of natural images patches and extract correlations from each patch
- 11 the ensemble of patches yield a multidimensional probability distribution of image statistics
- 12 we can extract correlations from or put correlations into visual textures
- 13 psychophysical experiments use synthetic binary textures in a segmentation task
- 14 task: identify the location of correlated texture
- 15 ...or in pairwise combinations
- 16 threshold values along cardinal and oblique directions define an discrimination contour
- 17 coordinates can be tuned individually ...
- 18 we extract correlations from images, and we measure human sensitivity to the same correlations
- 19 we predict that the variation in image statistics matches human sensitivity to the same statistics
- 20 natural scenes are most variable in second-, then fourth-, then third-order correlations
- 21 the variability of correlations in natural scenes predicts human sensitivity to the same correlations
- 22 covariance in natural images differs for symmetric versus asymmetric combinations of statistics
- 23 shape and orientation of inverse covariances predict human discrimination contours
- 24 what we've learned so far...
- 25 consider a channel coding problem:
- 26 do local correlations distinguish objects and boundaries?
- 27 we can separately estimates statistics within foregrounds and backgrounds
- 28 the square glider belongs to a broader class of informative gliders that produce salient patterns
- 29 are we blind to informative structure in other imaging modalities?
- 30 thank you!
- 31 [Demo]
