Video Compression: What is discrete cosine transform?

Question

I\'ve implemented an image/video transformation technique called discrete cosine transform. This technique is used in MPEG video encoding. I based my algorithm on the ideas pr

Answer 1

Anthony Cramp's answer looked good to me. As he mentions the DCT transforms the data into the frequency domain. The DCT is heavily used in video compression as the human visual system is must less sensitive to high frequency changes, therefore zeroing out the higher frequency values results in a smaller file, with little effect on a human's perception of the video quality.

In terms of using the DCT to compare images, I guess the only real benefit is if you cut away the higher frequency data and therefore have a smaller set of data to search/match. Something like Harr wavelets may give better image matching results.