Optical flow in PHP for meteo.lt radar pictures. Requires GD.
To initialize class you need two images. Optical flow calculation starts on class construction.
$opticalFlow = new TVL1($firstImage, $secondImage, $fineTune);
Dimensions of images must be the same. As script uses tons of memory
$fineTune parameter tells the script when to stop.
My sugesstion start at
$fineTune = 0 (finest scale), and increase it until memory/time limits are satisfying.
To draw optical flow as lines onto image use method Y2RGB:
$opticalFlow->Y2RGB($image, $scale, $thickness, $color, $step);
$image- GD image on which we draw optical flow
$scale- (float) optical flow scale factor, scales flow vectors and is used as drawing threshold
$thickness- thickness of lines (not used)
$step- defines flow drawing grid.
===== Original C code and article can be found here: http://www.ipol.im/pub/art/2013/26/