A method of phase diversity imaging is applied to reconstruct an overly extended object from stellar speckle images. The reconstruction algorithm is based on the iterative blind deconvolution method and the Gerchberg-Saxon phase retrieval procedure. Computer simulations for reconstructing solar granulations are conducted. The simulation results exhibit the effectiveness of the phase diversity method for high-resolution solar imaging.

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We investigated spatial frequency tuning of the mechanisms for stereoscopic depth perception, using a masking technique, and compared these tunings with those for luminance pattern detection. Observers discriminated depth direction in random-dot stereograms with various contrasts of a masking pattern, which was dichoptic stimulus of uncorrelated random dots. The strength of masking effect as a function of spatial frequency (i.e., masking function) was measured: masking function approximates the spatial frequency tuning of the mechanism that detects the depth in the test pattern. The masking functions for stereoscopic depth were found to be similar to either of the three of the six spatial frequency channels proposed by Wilson and Gelb (1984) for the detection of luminance patterns.

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We examined the tolerance of full-field illuminance changes to perceive constant illumination on the picture across saccades. In the experiment, subjects observed a picture of an actual scene, while the illuminance on the picture was alternated between E and E-ΔE whenever subjects made saccades. The subjects reported whether they noticed any changes in brightness or color in the picture. Thresholds for detecting illumination changes were measured at three illuminance levels. It was shown that the thresholds amounted to 40% decrement of illuminance on average, indicating there exists fairly large tolerance of additional illumination changes across saccades. It was also found that the illumination changes were less noticeable at lower illuminance levels.

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