Intraframe prediction

As described earlier, pure entropy coding does not perform well for images. Thus, some additional operation must be performed in both encoder and decoder as shown on pictures below.

	Coder:
	Decoder:

Images exhibit strong local correlation among pixels. See the picture below, where 3-line excerpt of Lena image is presented. As we can see, usually the pixel value is similar to the values of neighboring pixels. This observation is the base for DPCM method described on next page.