Open shiyun20 opened 7 years ago
@shiyun10 , I have seen a post said that the value less than 1.1 is perfect. And in the guetzli project, 1.0 is used. Just for your information.
@shiyun10 Less than 1.0 is best , 1.0-1.1 is acceptable , greater than 1.1 (not good).
I found more information on that in the guetzli (jpeg compression optimization) repo: https://github.com/google/guetzli/blob/b473cf61275991e2a937fe0402d28538b342d2f8/guetzli/quality.cc#L26
// Butteraugli scores that correspond to JPEG quality levels, starting at
// kLowestQuality. They were computed by taking median BA scores of JPEGs
// generated using libjpeg-turbo at given quality from a set of PNGs.
// The scores above quality level 100 are just linearly decreased so that score
// for 110 is 90% of the score for 100.
const double kScoreForQuality[] = {
2.810761, // 70
2.729300,
2.689687,
2.636811,
2.547863,
2.525400,
2.473416,
2.366133,
2.338078,
2.318654,
2.201674, // 80
2.145517,
2.087322,
2.009328,
1.945456,
1.900112,
1.805701,
1.750194,
1.644175,
1.562165,
1.473608, // 90
1.382021,
1.294298,
1.185402,
1.066781,
0.971769, // 95
0.852901,
0.724544,
0.611302,
0.443185,
0.211578, // 100
0.209462,
0.207346,
0.205230,
0.203114,
0.200999, // 105
0.198883,
0.196767,
0.194651,
0.192535,
0.190420, // 110
0.190420,
};
I using butteraugli compare two image, the result value is "0.971608", according the result value, how can I know the two image match is perfect or ok or bad?