Python Image Processing Cookbook

How it works...

As you can see from the previous section, many of the sketching techniques work by blurring the edges (for example, with Gaussian filter or diffusion) in the image and removing details to some extent and then subtracting the original image to get the sketch outlines.

The gaussian() function from the scikit-image filters module was used to blur the images.

The anisotropic_diffusion() function from the filter.smoothing module of the medpy library was used to find edges with anisotropic diffusion (a variational method).

The dodge operation divides (using np.divide()) the image by the inverted blurred image. This highlights the boldest edges in the image.