Feature Detector and Descriptor
Table of Content
Harris
Gradient-based corner detector. bmvc88
Shi-Tomasi
Gradient-based corner detector. cvpr94 paper
SIFT
(scale invariant feature transform) Gradient-based corner detector and descriptor. iccv99 ijcv04 Main steps:
- Scale-space extrema detection: The image is convolved with Gaussian filters at different scales, and then the difference of successive Gaussian-blurred images are taken. Keypoints are then taken as maxima/minima of the Difference of Gaussians (DoG) that occur at multiple scales.
- Keypoint localization: 2.1 Interpolation of nearby data for accurate position 2.2 Discarding low-contrast keypoints 2.3 Eliminating edge responses
- Orientation assignment Each keypoint is assigned one or more orientations based on local image gradient directions, and the gradient magnitude and orientation are precomputed using pixel differences.
- 128-d Keypoint descriptor Create a set of orientation histograms on 4×4 pixel neighborhoods with 8 bins each
SURF
(speeded-up robust features) Gradient-based eccv06
FAST
(features from accelerated segment test) Intensity-based corner detector. eccv06 procedure Remarks:
- Check 1,5,9,13 for fast detection;
- Non-maximum suppression.
BRIEF
(binary robust independent elementary features) eccv10
BRISK
(binary robust invariant scalable keypoints) iccv11
ORB
(oriented FAST and rotated BRIEF) iccv11
FREAK
(fast retina keypoint) cvpr12