什么是量化表(Quantization Tables )

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Quantization Tables

In JPEG, each F[u,v] is divided by a constant q(u,v).

Table of q(u,v) is called quantization table.

----------------------------------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  113  92   49  64  78  87  103  121  120  101  72  92  95  98  112  100  103  99   ----------------------------------

Eye is most sensitive to low frequencies (upper left corner), less sensitive to high frequencies (lower right corner)
Standard defines 2 default quantization tables, one for luminance (above), one for chrominance.
Q: How would changing the numbers affect the picture (e.g., if I doubled them all)?
Quality factor in most implementations is the scaling factor for default quantization tables.
Custom quantization tables can be put in image/scan header.