Module for working with image data.
Find the centroid (cx,cy) of image where:
Returns image pixel coordinates of centroid in box of size:
2*distance+1
around coordinates (x,y) in image.
Implementation of the IRAF zscale algorithm to find vmin and vmax parameters for the dynamic range of a display. It finds the image values near the median image value without the time consuming process of computing a full image histogram.