2014-09-16 11:11:35 -0600 | asked a question | Low quality image comparing Hi! I have web service for searching my images. I use opencv (2.4.9) orb feature to get keypoints and Phash lib to convert them into unsigned bigint numbers, that can be compared with the hamming distance. As I remember, it worked fine, but since some magic happens, the quality of comparison became very low. For example, even making a little watermark on image makes 70% difference of keypoints (even using comparion with hamming distance). What could happens? Here is code (python2) I use to get keypoint hashes: matcher.hashes() implimentation: System is typical vps: Linux version 3.2.0-4-amd64 ([email protected]) (gcc version 4.6.3 (Debian 4.6.3-14) ) #1 SMP Debian 3.2.54-2 I don't know whether any other info is required Image examples for compare attached: 11.jpg and 22.jpg . I got about 170 hashes for them, but only 9 are alike (with hamming distance <=7). Thanx. |