Expert

Image Compression: Quantization:
In the third step of an image compression process, the quantization takes place.
 

Inverse Quantization in JPEG:
Quantization and dequantization of JPEG must use the same tables.
 

Image Compression: Quantization in JPEG:
The quantization in the JPEG process is a lossy transformation. The 64 coefficients obtained from the DCT step are quantized with a table with 64 entries. Each coefficient can be adjusted separately. Therefore, the relative signifiance of the different coefficients can be influenced and specific frequencies can be given more importance than others.