[EMAIL PROTECTED] wrote: > But how should the 256-item mapping table look like, if the > threshold is 18( found from the histogram)
here's one way to do it: threshold = 18 table = [] for i in range(256): if i < threshold: table.append(0) # black else: table.append(255) # white out = im.point(table) there are shorter ways to write this; the above was written for clarity. quite often, passing in a function instead of a table can make the code shorter: threshold = 18 def map(i): if i < threshold: return 0 return 255 out = im.point(table) there are plenty of ways to do this in one line as well, but I'll leave that as an exercise. </F> _______________________________________________ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig