Image Compression Techniques
Image compression is minimizing the size in bytes of a graphics file without degrading the quality of the image to an unacceptable level. The reduction in file size allows more images to be stored in a given amount of disk or memory space. It also reduces the time required for images to be sent over the Internet or downloaded from Web pages.
- An approximate reconstruction of original data. The loosy compression that produces the imperceptible difference can sc called visually lossless.
- There is some Loss of information
- Used at low bit rates introduce compression artifacts.
- Higher compression ratio is achieved with the loosy compression. This is achieved at cost of losing out finer details of an image.
- Image & music too need not be reproduced exactly an approximation of original image is enough for most purposes.
- Loosy method are suitable for natural images such as photos in applications when minor loss of fidelity is acceptable to achieve a required image.
- This is the exact replica of an original image.
- There is no loss of quantitative information
- It require higher bit rate for transmission.
- Compression ratio is low. Compression ratio defined as ratio of size of uncompressed image to size of compressed file.
- Used for archival purpose &often medical imaging, technical drawings, clip art or comics.
- Text compression, text document &binary executable must be compressed in this technique. They need to be exactly reproduced.