Perception Of High-Pass Filtered Images
Eli Peli · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1987
Many visual illusions and Gestalt grouping phenomena may be explained by low-pass filtering of these images by the visual system. However, the perceptions of these images are maintained even if such images are high-pass filtered before display, removing the low-frequency information. Many such high-pass filtered images can be treated as a form of two-dimensional amplitude modulation (2-D AM) signals. The low-frequency figure information is coded in the modulation envelope, which disappears with the carrier if low-pass filtered. The envelope may be retrieved (demodulated), using one of many non-linear operations followed by a low-pass filter. Theory and image-processing simulations show that the compressive non-linearity of the visual system suffices to demodulate these images. This model accounts for various perceptual phenomena associated with filtered images and band-limited psychophysical stimuli.