Grey-scale versus color coding of acoustic data images

Acoustic data images were studied using both grey-scale and color coding for 8 to 64 discriminable levels of information. Display image encoding using 8 discriminable levels of grey-scale or color was shown to provide good perception of pattern features. Beyond 8 levels, it was increasingly more difficult to distinguish individual levels and pattern perception was degraded. With 32 to 64 levels of quantization available, excellent pattern perception was achieved using a color 'band-step' coding scheme. The color bands code the major levels of amplitude, while the intensity gradient within each band highlights contouring and provides for finer amplitude discrimination. The use of six color bands of 5 to 10 intensity steps within each band was particularly effective. Color displays were shown to be superior for the perception of patterning, contouring, and equivalent amplitudes and also to be equivalent to grey-scale displays for discriminating patterns of very weak signals in noise.