Mastering OpenCV 3 - Second Edition

Generating an evil mode using edge filters

Cartoons and comics always have both good and bad characters. With the right combination of edge filters, a scary image can be generated from the most innocent looking people! The trick is to use a small-edge filter that will find many edges all over the image, then merge the edges using a small Median filter.

We will perform this on a grayscale image with some noise reduction, so the preceding code for converting the original image to grayscale and applying a 7x7 Median filter should still be used (the first image in the following figure shows the output of the grayscale Median blur). Instead of following it with a Laplacian filter and Binary threshold, we can get a more scary look if we apply a ...