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1

SPIHT

BY,

PRAVEEN.M.K-9913107002

1Yr M.Tech(D.C.N)

KLU

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2 What is IMAGE Compression? Reduce the size of data.

Also, Compression is a way to reduce the number of bits in a frame but retaining its meaning.

**(For e.g..,5Mb data is reduced to 1.47Mb.)**

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3 Need for IMAGE compression….??

For large storage requirements.(for e.g.., Encyclopedia).

Relatively used in the medical field to transfer the patients CT-scan image. Etc..,

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4 Types:

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5 SPIHT: SPIHT means Set Partitioning in Hierarchical Trees.

This was proposed by Pearlman in 1996.

It is an image compressing method of DWT and it belongs to lossless compression technique.

wavelet

transform

SPIHT

encoding

original

image

bit

stream

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6

Three-Level Haar function of Wavelet Transformation Structure(compression):

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7Formation of cells:

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8ALGORITHM: O(i,j): set of coordinates of all offspring of node (i,j); children only

D (i,j): set of coordinates of all descendants of node (i,j); children, grandchildren, great-grand, etc.

H (i,j): set of all tree roots (nodes in the highest pyramid level); parents

L (i,j): D (i,j) – O(i,j) (all descendents except the offspring); grandchildren, great-grand, etc.

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9COMPRESSING OF PIXELS:

A DCB A+B C-DA-BC+D

20

17

15

16

30

31

20

22

15

21

18

22

17

19

25

18

35

33

50

53

5

1

10

9

33

43

42

37

-3

-1

-8

1

original image

Compressed image

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10 COMPRESSED IMAGE:

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11DECOMPRESSED IMAGE:

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12 Properties of SPIHT:

Good image quality with a high PSNR Fast coding and decoding A fully progressive bit-stream Can be used for lossless compression May be combined with error protection Ability to code for exact bit rate or PSNR

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13