Wrong Hamming norm value between two ORB descriptors

asked 2016-01-27 06:27:09 -0600

ale_Xompi gravatar image

I'm currently working on feature point tracking and I want to compare the ORB descriptor of the current point with the previous one. I want to discard that point if the hamming distance between the two descriptors is higher than a specific threshold.

When I'm running hamm_dist = norm(pointDescr1, pointDescr2, NORM_HAMMING), the returned value sometimes is greater than 32 and I can't understand why. I was thinking it should be between 0 and 32.

Please let me know if you have an explanation. Thank you in advance.

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Hamming distance is bits that differ. You may be mistaking 32 bytes for 32 bits.

Der Luftmensch gravatar imageDer Luftmensch ( 2016-01-27 08:12:26 -0600 )edit

Thank you for your answer. Yes, you're right. That means the range of the Hamming distance between two ORB descriptors is [0,256], right?

ale_Xompi gravatar imageale_Xompi ( 2016-01-27 10:27:41 -0600 )edit