ESBIFT
Extremely Simple Brightness Invariant Feature Tracking
... anymore but there is more to correct left it seems: lookupRawDescriptorV(isValid, x, y, image.featureLayers[imageLevel], pair,
descriptorSize, c0a, c1a, 0, 0,
DEGREETORADIANS(angle45Id * 45.0));) (It's no fault of Sourceforge, currently the -angle45Id works better again whyever..)
At least on par with Kanade Lucas Tomasi (KLT) and similar or more advanced Keypoint Trackers.