Evaluation of image metrics for target discrimination using psychophysical experiments

Abstract

Image clutter affects the perceptual ability of any system for object detection. A procedure for conducting psychophysical experiments has been developed to test computational models for the perceptual similarity or difference of texture patterns, which contributes to image clutter. This experimental procedure is based on Thurstone’s law of comparative judgment, which is used along with the method of paired comparisons to assign relative psychological scale values to image stimuli. To facilitate consistency in the presentation of stimuli and collection of data, an X-windows testing environment has been developed called the X-based perceptual experiment testbed. Using this experimental procedure, a pilot study was conducted in which the image stimuli consisted of targets and backgrounds with texture patterns of uncorrelated Gaussian noise. With such patterns, only first-order image statistics are of significance. The psychological scale values relating the level of ‘‘target distinctness’’ in each of the image stimuli were compared to several first-order image metrics. Correlation coefficients as high as 0.9881 were found between the scale values and the image metrics.