Hello all! Is getting of tilted integral sum is necessarily for implementing Viola-Jones method? It seems to me that I saw some realizations which don't use tilted integral sum. This kind of integral image is some strange for me, I can't understand it...
No, the tilted integral image is not needed for the Viola Jones algorithm. In fact, the original Viola Jones Paper only uses upright (=untilted) Haar-like features.
In An Extended Set of Haar-Like Features for Rapid Object Detection, Rainer Lienhart , Jochen Maydt, ICIP 2002 the authors showed that extending the original feature set with those tilted Haar-like features improves performance, i.e. the false positive rate was reduced.
AFAIK the Haar-cascade detector in OpenCV uses both normal and tilted Haar-like features by default. I suppose other object classes benefit more from tilted features than faces.
yes, it's essential. please read the paper: http://research.microsoft.com/~viola/Pubs/Detect/violaJones_IJCV.pdf
the viola-jones method is all about comparing rectangles, is the left one brighter than the right ?
with those integral images, the check is just a handful of array lookups and adds, without, you'd have to loop through the image region every time, to get it's intensity
Asked: 2013-02-19 12:21:22 -0600
Seen: 825 times
Last updated: Feb 19 '13
