Theoretical role of square wavelet analysis in stereopsis and binocular rivalry: a mathematical model and computer simulation.

To determine stereopsis, a mathematical model and computer simulation specify that square wavelet coefficients be independently estimated for the images in each eye. Then, by comparing these independently determined coefficients, the model theorizes that the visual system both identifies those parts of the two images which lie across corresponding points and identifies those parts of the two images which lie across noncorresponding or disparate points. Given the latter occurrence, the retinal disparity is evaluated as being either stereopsis or binocular rivalry.

Visual image analysis by square wavelets: empirical evidence supporting a theoretical agreement between wavelet analysis and receptive field organization of visual cortical neurons.

It was proposed that the human visual system analyzes images into square wavelets. To test this view, comparisons were made between the perceived similarity-dissimilarity of alphabet letters and the wavelet analyses of those same letters. For the proposal to be considered tenable, the coefficients of the wavelet analysis of similar letters must be similar, and the coefficients of the wavelet analysis of dissimilar letters must be dissimilar.

The problem of the missing wavelet.

A block face was generated by dividing a drawn face into a matrix of rectangular cells and then making the brightness of each cell equal to the average of the brightnesses within the facial area circumscribed by a cell. A wavelet analysis was performed on the numbers representing the brightnesses of the cells in each row of the matrix, and from each row, the wavelet was deleted which corresponded to the fundamental or the lowest frequency sine wave of a complex wave. The appearance of the block face was not substantially altered by the deletion of the wavelet corresponding to the fundamental.

Changes in perceived color with intermittent illumination.

Using 24 observers with normal color vision, perceived shifts in hue were determined for a yellow-red, green, and blue-green at intermittencies of 5, 10, and 20 cps. The hue shift for yellow-red was consistent with the hue shift exhibited by a deuteranomalous observer while the hue shift for green and blue-green was consistent with that exhibited by a protanomalous observer.

Ebbinghaus illusion: effect of figural similarity upon magnitude of illusion when context elements are equal in perceived size.

The magnitude of the Ebbinghaus illusion has been reported to be greater when test element and context elements are figurally similar as opposed to figurally dissimilar. In the current investigation with 16 observers, illusion magnitude was greater for a figurally similar configuration even though the context elements of the figurally similar configuration were perceived as smaller than the context elements of a figurally dissimilar configuration. Hence, figural similarity appears to have a prepotent effect in the Ebbinghaus illusion.