How Many Gray Levels are Required to Represent a Gray Texture Image Using Histogram Equalization?

Most gray images don’t always require an 8-bit representation for each pixel; in particular, a pixel of texture images may even be coded in no more than 5 bits (32 gray levels). Adequately enough it is probable that between 16 to 32 levels of gray could be a suitable threshold for most gray level texture image representation, before the image shows signs of false contouring or any notable rough edges. This research uses a variety of texture images that have been re-quantized according to histogram equalization: a methodology that increases the contrast of an image by using the image’s histogram. All the data gathered were from a survey conducted by 50 independent test subjects. A nonparametric sign test indicates that 8 levels would be enough to encode a gray texture image for most of the test images from Brodatz’ album.