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OpenCV Latch Feature Descriptor Explanation

Detailed Description

latch Class for computing the LATCH descriptor. If you find this code useful, please add a reference to the following paper in your work: Gil Levi and Tal Hassner, “LATCH: Learned Arrangements of Three Patch Codes”, arXiv preprint arXiv:1501.03719, 15 Jan. 2015

LATCH is a binary descriptor based on learned comparisons of triplets of image patches.

bytes is the size of the descriptor - can be 64, 32, 16, 8, 4, 2 or 1 rotationInvariance - whether or not the descriptor should compansate for orientation changes. half_ssd_size - the size of half of the mini-patches size. For example, if we would like to compare triplets of patches of size 7x7x then the half_ssd_size should be (7-1)/2 = 3. sigma - sigma value for GaussianBlur smoothing of the source image. Source image will be used without smoothing in case sigma value is 0.

Note: the descriptor can be coupled with any keypoint extractor. The only demand is that if you use set rotationInvariance = True then you will have to use an extractor which estimates the patch orientation (in degrees). Examples for such extractors are ORB and SIFT.

Note: a complete example can be found under /samples/cpp/tutorial_code/xfeatures2D/latch_match.cpp

static Ptr<LATCH> cv::xfeatures2d::LATCH::create  ( int   bytes = 32,
bool  rotationInvariance = true,
int   half_ssd_size = 3,
double  sigma = 2.0 

Published Feb 4, 2024

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