POV-ray renderer

The next step is to implement Chen's rendering method used in her thesis.

Using two textures to replace the lines

The alpha map should be added to remove the artefacts.

Triangulation based on edges

Extract edges from three methods: canny, etf, and thresholding gradients. Then construct a triangulation from the points on the edges.  

Gradients might be a better way for the irregular embroidery

Choose a threshold of gradient magnitudes and densely draw short straight lines for each pixels. Since we do not care how many stitches, gradients decide the boundaries nicely. Then maybe we can think about the inner directions to have some contrast.Have to find a way  to distinguish three contents: background, texture, and smooth parts.I am thinking to interactively define them if we cannot find an automatic way in a short time.

A few more examples by the over-smoothed field

Smoothness of the field

Randomly place 4000 stipples and use different smoothing times to draw a short line for each stipple. The line direction is based on the vector field.

Replace a stipple with an 'x' pattern

Rendering parts should be added for effects.