Computer Science 1033A/B Lecture Notes - Lecture 5: Lossless Compression, Color Depth, Lossy Compression

• School: Western University
• Department: Computer Science
• Course: Computer Science 1033A/B
• Professor: Laura Reid

Document Summary

Compression for images with large blocks of same colour. Raw stores info about each pixel one at a ime. Each colour is 3 byte (60 000 bytes info) Compression helps with making smaller ile size download faster images. Designers of jpeg compression algorithm realized that human eye is more sensiive to brightness details than to ile colour details. If it inds two adjacent pixels with very similar colours, will store both those pixels with the same colour and discard the other. Looks for large block of area that all have same colour. Saving image with 24 bit colour as gif will lower quality the irst ime you convert it to a gif. Not good for photography because can only store 256 colours. Soluion 1: subsitute one of the colors you have for one of the colors you are missing. Png (ping) created because of licensing issues with gifs in the 90s does lossless compression similar to gif.