1. A method of analyzing an image data set, comprising: determining a number of on-pixels in the image data set; performing a morphological operation on the image data set, yielding a processed image data set including processed on-pixels; deriving a metric from a relationship between a number of on-pixels in the image data set and a number of processed on-pixels in the processed image data set; and using the metric to estimate a compression performance associated with the image data set.