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    - DCT
    - Coefficient Quantization
    - Lossless Compression


The JPEG lossy compression algorithm consists of three successive stages, shown in the flow chart below.

DCT Transformation --> Coeff Quantization --> Lossless Compression

Both DCT transformation and the final compression of the quantized data are, for the most part, lossless procedures (negligible precision may be lost during DCT transformation due to minor numerical round-offs). This leaves the coefficient quantization phase as the driving force behind JPEG’s overall "lossyness". It is in this step that insignificant data concerning the image is discarded. All three stages are described next.

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