BIT-PLANE CODING

Bit-plane coding Bit-plane decomposition Constant area coding One-dimensional run-length coding

AGENDA

Reducing an image’s inter-pixel redundancy is to process the image’s bit planes individually.

First decompose the original image into bit-plane. Binary image compression approach

run-length coding (RLC).

BIT-PLANE CODING

BIT-PLANE CODING(EXAMPLE)

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The gray levels of an m-bit gray-scale image can be represented in the form of the base 2 polynomial.

am-12m-1 + am-22m-2 + ……a121 + a020

Based on this property, a simple method of decomposing the image into a collection of the binary images.

The disadvantage of this approach is that small change in the gray level can have the significant impact of the complexity of the bit plane

BIT-PLANE DECOMPOSITION

A simple method to compressing a binary image or bit plane is to use special code words to identify large area of contiguous 1’s or 0’s.

A images is divided into block of size p*q pixels,which are classified as all white,all black,or mixed intensity.

for2D blocks a solid white images is coded as 0 and all other images are coded as 1.

CONSTANT AREA CODING

An effective alternative to constant area coding to represent each row of an image

Developed in 1950. Standard compression approach in FAX coding Approach◦Code each contiguous group of 0’s or 1’s

encountered in a left to right scan of a row by its length

◦Code black and white run lengths separately using variable-length coding

Code black and white run lengths separately using variable-length coding

ONE-DIMENSIONAL RLC