This document discusses different types of error free compression techniques including variable-length coding, Huffman coding, and arithmetic coding. It then describes lossy compression techniques such as lossy predictive coding, delta modulation, and transform coding. Lossy compression allows for increased compression by compromising accuracy through the use of quantization. Transform coding performs four steps: decomposition, transformation, quantization, and coding to compress image data.

1. S.Nandhini
II-M Sc(CS&IT),
Nadar Saraswathi College of Arts and Science,
Theni.

2. ERROR FREE COMPRESSION
 Error free compression is the only acceptable means of data
reduction.
 One such application is the archival of medical or business
documents.
 Need for error free compression is motivated by the intended
use or nature of the images under consideration.

3. There types in error free compression
 Variable-length coding
 Huffman coding
 Arithmetic coding
 Variable-length coding
 Error-free image compression is to reduce
only coding redundancy.
 coding redundancy normally is present in
any natural binary encoding of the gray level in an image.

4. HUFFMAN CODING
 Coding the symbol of an information source individually.
 Huffman coding yields the smallest possible number of
code symbols per sources symbol.
 The constraint that the source symbol be coded one at a
time.

6. ARITHMETIC CODING
 Arithmetic coding generates non-block codes.
 A one-to-one correspondence between source symbols and
code words does not exist
 Sequence of source symbols is assigned a single arithmetic
code word.

8. LOSSY COMPRESSION
 Lossy compression encoding is based on the concept of
compromising the accuracy
 The reconstructed image in exchange for increased
compression.
 The resulting distortion can be tolerated
 The increase in compression can be significant.

9. LOSSY PREDICTIVE CODING
 Add a quantizer to the model introduced examine the
resulting trade-off between reconstruction accuracy and
compression performance.
 Lossy predictive coding model
 A)encoder
 B)decoder

10. ENCODER AND DECODER

11. DELTA MODULATION
 Delta modulation(DM) is a simple but well-known form of
lossy predictive coding in which the predictor and quantizer
are defined

12. DELTA MODULATION

14. TRANSFORM CODING
 Transform coding a reversible, linear transform is used to
map the image into a set of transform coefficients.
 Which are then quantized and coded.

15. TRANSFORM CODING

16. Performs four relatively straightforward operations
 DECOMPOSITION
 TRANSFORMATION
 QUANTIZATION
 CODING
An NXN input of image first is subdivided into subimages
of size nXn.
Which are then transformed to generate(N/n)2 sub image
transform arrays.

17. THANK YOU