How does Vuforia image recognition work?

Question

I am using the Vuforia SDK to build an Android application and am curious as to how the marker tracking works. Does the app convert the video frame into byte codes and then compare these against the .dat file generated by creating the marker? Also, where is this code found in the Vuforia sample app, is it in the C++ ? Thanks.

Answer 1

Vuforia uses edge-detection technique. If there are more vertices or lines in the high-contrast image then its a high rated image for Vuforia. So, we can say that their algorithm is somewhat similar to SIFT.

Answer 2

Well, you don't see the code for recognition and tracking because they are Intellectual property of Qualcomm and usually should not be revealed. Vuforia is not an open-source library.

Vuforia first detects "feature points" in your target image [Web-based target management] and then uses the data to compare the features in target image and the receiving frame from camera.

Google "Natural feature detection and tracking" which falls under Computer Vision area and you will find interesting stuff.

Answer 3

No, detection and tracking code placed in libQCAR.so But question "how its work" is to complex to answer here. If you want to be familiar with object detection and tracking - start to learn method as mser, surf, sift, ferns and other.