This is our fifth post in the series about binary descriptors and here we will talk about the FREAK descriptor. This is the last descriptor that we’ll talk about as the next and final post in the series will give a performance evaluation of the different binary descriptors. Just a remainder – we had an introduction to binary descriptors and posts about BRIEF, ORB and BRISK.
Why Binary Descriptors?
Following the previous post on descriptors, we’re now familiar with histogram of gradients (HOG) based patch descriptors. SIFT, SURF and GLOH have been around since 1999 and been used successfully in various applications, including image alignment, 3D reconstruction and object recognition. On the practicle side, OpenCV includes implementations of SIFT and SURF and Matlab packages are also available (check vlfeat for SIFT and extractFeatures in Matlab computer vision toolbox for SURF).
So, if there no question about SIFT and SURF performance, why not use them in every application?