Computer Science 1033A/B Lecture Notes - Lecture 2: Lossless Compression, Raster Graphics, Huffman Coding

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

Document Summary

After 1800"s we could record by writing books. After 1900 we could record sound and photographs. Language is represented through letters and words. Saved thoughts through diaries and journals (now blogs) Pixels in an image match pixels on the monitor. When printing dots per inch make a difference. On the screen pixels makes a difference. When enlarged, the computer adds new pixels and guesses on the colour to colour the new pixels (interpolation) based on surrounding pixels. Objects consist of lines, curves and shapes. As image is enlarged, there are crisp clean lines. Vector image size has a smaller file size than the same image stored as a bitmap. Use binary code to represent words, numbers, sound and images. Compresses down the exact image, detail and quality is preserved. Less bits/bytes without losing any of the original information. Takes away unnecessary information (cannot be added back) Selected portions of the image are discarded but most important areas remain.