Christopher W. Tyler and Richard Miller

The Smith-Kettlewell Eye Research Institute

2318 Fillmore St., San Francisco, CA 94115, USA 


Morphonome® software for image psychophysics on the Macintosh family of computers allows generation and presentation of a wide spectrum of 2-D grayscale and color contrast images for psychophysical testing of the limits of human perception. The application is written for and requires a color monitor for full grayscale function. 

The images are generated under parametric control to permit a wide variety of both standard and novel experiments in perceptual limits, psychophysical detection threshold, contrast masking, contrast discrimination, contrast matching, adaptation, lateral interactions, and so on. 
 

Spatial patterns are based on sinusoidal, triangular and square-wave luminance profiles, with linear, radial, spoke and checkerboard 2D configurations. Spatial frequency, orientation and phase are freely selectable 2D Gaussian and 2D difference of Gaussian profiles are also available. Binary one-pixel noise can also be selected as a test stimulus or masking pattern over other stimuli. 

Patterns may be windowed with square, circular, sector, annular sector, Gaussian fade, derivative of Gaussian, Gaussian ring, vernier split, and multiple-patch functions. Pairs of patterns may be mixed by one-pixel interlace. Several types of fixation target may be placed in any location. 
 


The images are of psychophysical quality, with a unique method of expanding grayscale to 10.8-bit resolution using the conventional 3 x 8-bit RGB monitor and 24-bit video card without hardware modifications. The display will scale itself to any monitor size. 

The luminance scale is fully linearizable to 99.5% output contrast (calibration of your monitor required). A parametrically variable sample of distortion "gamma" functions is provided to allow perceptual equalization of the luminance scale for specific applications. 
 

The luminance scale is fully linearizable to 99.5% output contrast (calibration of your monitor required). A parametrically variable sample of distortion "gamma" functions is provided to allow perceptual equalization of the luminance scale for specific applications. 

Adjustment, YES-NO with variable blank trials and two-interval forced-choice procedures are selectable, either as constants stimulus or staircase methods. 
 


System Compatibility: Mac II family and Quadra with I MB RAM, 68882 Floating Point Coprocessor, or Power PC systems including G3 and iMAC, requiring an RGB monitor of any standard size with 24-bit video card. System 6.07, 7 and 8 compatible. (Note, the SK Calibrator available for the requisite monitor linearization is not yet compatible with the iMAC bus.)

The MORPHONOME® Image Psychophysics Software was developed at Smith-Kettlewell under a Developer Agreement with Apple Computer, whereby it needs to be offered as a commercial product.

Our future plans include extension to 2D stereo, motion and color stimulus varieties.


 
 

"The Morphonome® Image Psychophysics Software and Calibrator for Macintosh System", Christopher W. Tyler and Brennan McBride, SPATIAL VISION (10, 479-484)

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