I want to push several hundred greyscale images through a threshold filter, so that an output pixel is black or white according to whether the corresponding input pixel is less or more than 1\/2 bright. (My goal is a ‘woodcut’ effect.)<\/p>\n
ImageMagick can apparently do this with one command, but I lack a library that it needs.<\/p>\n
GIMP has a menu command with this function, but to do it from a script it seems I’d need to learn Scheme.<\/p>\n
I could write a program using Python Imaging Library (which I’ve used to output most of my mathematical designs in recent years), but so far in RTFM I can’t tell how to, y’know, access the pixels it reads in. Later:<\/strong> Found a better FM<\/a>.<\/p>\n Wish me luck.<\/p>\n","protected":false},"excerpt":{"rendered":" I want to push several hundred greyscale images through a threshold filter, so that an output pixel is black or white according to whether the corresponding input pixel is less or more than 1\/2 bright. (My goal is a ‘woodcut’ … Continue reading