Detecting FAST features at multiple scales

FAST has been introduced as a quick way to detect keypoints in an image. With SURF and SIFT, the emphasis was on designing scale-invariant features. More recently, new interest point detectors have been introduced with the objective of achieving both fast detection and invariance to scale changes. This recipe presents the Binary Robust Invariant Scalable Keypoints (BRISK) detector. It is based on the FAST feature detector that we described in a previous recipe of this chapter. Another detector, called ORB (Oriented FAST and Rotated BRIEF), will also be discussed at the end of this recipe. These two feature point detectors constitute an excellent solution when fast and reliable image matching is required. They are especially efficient when they are used in conjunction with their associated binary descriptors, as will be discussed in Chapter 9, Describing and Matching Interest Points.

How to do it...

Following what we did in the previous recipes, the...