I am doing some research on image compression via discrete cosine transformations and i want to change to quantization tables sizes so that i can study what happens when i change the matrix sizes that i divide my pictures into. The standard sub-matrix size is 8X8 and there is a lot of tables for those dimensions. For example the standard JPEG quantization table (that i use) is:
standardmatrix8 = np.matrix('16 11 10 16 24 40 51 61;\
12 12 14 19 26 58 60 55;\
14 13 16 24 40 57 69 56;\
14 17 22 29 51 87 80 62;\
18 22 37 56 68 109 103 77;\
24 35 55 64 81 104 103 92;\
49 64 78 77 103 121 120 101;\
72 92 95 98 112 100 103 99').astype('float')
I have assumed that the quantization tabel for 2X2 and 4X4 would be:
standardmatrix2 = np.matrix('16 11; 12 12.astype('float')
standardmatrix4 = np.matrix('16 11 10 16;
12 12 14 19;
14 13 16 24;
18 22 37 56').astype('float')
Since the entries in the standard table correspond to the same frequencies in the smaller matrixes.
But what about a quantization with dimentions 16X16, 24X24 and so on. I know that the standard quantization tabels are worked out by experiments and can't be calculated from some formula, but i assume that someone have tried changing the matrix sizes before me! Where can i find these tabels? Or can i just make something up and scale the last entries to higher frequenzies?
