Viola-Jones' Haarcascade visualisation

This is an unusual visualisation of haarcascades. Often, only haarcascade features are drawn. This visualisation however, adds up all matching features in an image. Resulting in a sort of lense which shows the contrasts in the image that the algorithm picks up on most.

• The visual_haarcascades binary (main.rs) uses V4L to capture webcam input and renders to a canvas.
• test.rs binary is an ugly program that looks hard-coded for haarcascade_frontalface_alt2.xml and test.png. It renders the output to test-output.png.
• The library is made for use with eg. Python through cffi. See eg. this repo

build

Most importantly

cargo build --lib --release

Notes

It could be that the code in commit f9b066a166fb0d2f042c6f745fa0ffbcce100666 is actually faster than the current master. While this is certainly not the case in a debug build (HEAD is way faster!), a release build seems to bring it up to higher speeds... confusing :-)