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Digital Image ProcessingUsing MATLAB

J.Nageswara Rao,M.Veerraju ,

MCA 2 nd YEAR,GIET Rajahmundry

By

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Digital Image ProcessingUsingMATLAB

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Digital Image

Digital image is composed of finite number of elements

Elements Picture Elements, Image Elements, Pels or Pixels

Pixel is used to denote the elements of a digital image

A digital image is a mapping from the real three-dimensional world to a set of two-dimensional discretepoints. Each of these spatially distinct points, holds anumber that denotes grey level or colour for it, and can beconveniently fed to a digital computer for processing.

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Digital Image Processing ( DIP )

?

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Digital Image Processing deals with images which are two-dimensional entities (such as scanned

office documents, x-ray films, satellite pictures, etc)captured electronically through a scanner or camera system that digitises the spatially continuous coordinates to a sequence of 0 s and

1 s .

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Types Of Computerized Process

Action :Segmentation

Input : ImageOutput : Attributes

Examples : Object

recognition,classification &processing

Mid Level Process

Action : Primitive Operations

Input : ImageOutput : Image

Examples : Noiseremoval, imagesharpening

Low Level Process

Action : Making Sensation

Input : AttributesOutput : SceneUnderstanding

Examples : recognition,analysis & associateswith vision

High Level Process

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Types of Images4

1. Intensity Image its a data matrix whose values arerepresented by intensities .

2. Binary Image stored as logical array with 0s or 1 s

3. Indexed Image has two components Data matrix x &Color map matrix map(Mx3 array having the value

range[0,1])

4. RGB Image it is an MxNx3 array of color pixelscorresponding to Red, Green & Blue .

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Introduction to MAT LAB

MATLAB stands for matrix laboratory .

MATLAB is a high-performance language for technicalcomputing.

It integrates computation, visualization, and programmingin an easy-to-use environment .

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MAT LAB Contd .,

Typical uses include

Algorithm development

Data acquisitionModeling, simulation, and prototypingData analysis, exploration, and visualizationScientific and engineering graphics

Math and computation Application development, including graphical user interface building

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Parts of MATLAB5

Development environment :- set of tools and facilities that helpsto use of MATLAB functions and files.

The MATLAB mathematical function library :- v ast collection of computational algorithms ranging from elementary functions tomore sophisticated functionsThe MATLAB language : consists of control flow statements,functions, data structures, input/output, etc., Graphics :-for two-dimensional and three-dimensional data visualization, image processing, animation, and presentation

graphics The MATLAB application program interface (API) :-library thatallows you to write C and Fortran programs that interact withMATLAB.

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Working Environment of MATLAB

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Commands in MATLAB

imread( filename )or

f = imread( D:/my images/eagle .jpg );

clc or clear

size( f )1024 1024

whos f Name Size Bytes Class

f 1024x1024 1048576 uint8 arrayGrand total is 1048576 elements using 1048576 bytes

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Writing images

imwrite( f,filename )or

imwrite( f,eagle,jpg )

or

imwrite( f,eagle.jpg )

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To show the information of image

imfinfo eagle.jpgFilename: 'eagle.jpg'FileModDate: '29-Aug-2007 10:01:40'FileSize: 334Format: jpg'FormatVersion: ''

Width: 1Height: 1BitDepth: 8

ColorType: 'grayscale'FormatSignature: ''NumberOfSamples: 1CodingMethod: 'Huffman'CodingProcess: 'Sequential'Comment: {}CodingMethod: 'Huffman'CodingProcess: 'Sequential'Comment: {}

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To Display A Image

imshow (eagle.jpg );

Or

imshow ( f );

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To display two images

imshow( f ), figure, imshow( g )

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Two Images in single Window

[X1,map1] = imread( 'eagle.jpg' );[X2,map2] = imread( 'testfire.jpg' );

subplot (1,2,1 ) , imshow(X1,map1)subplot (1,2,2 ) , imshow(X2,map2)

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[X1,map1] = imread('eagle.jpg');[X2,map2] = imread('testfire.jpg');[X3,map3] = imread('eagle.jpg');

subplot (1,3,1 ) , imshow(X1,map1)subplot (1,3,2 ) , imshow(X2,map2)subplot (1,3,3 ) , imshow(X3,map3);

subplot (3,1,1 ) , imshow(X1,map1)subplot (3,1,2 ) , imshow(X2,map2)subplot (3,1,3 ) , imshow(X3,map3)

Column Wise Image Representation

More Images in single Window

Row Wise Image Representation

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RGB to Grayscale Image Conversion

k = rgb2gray( r );

imshow( k );

r=imread( peppers.jpg ');

imshow( r );

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Grayscale to Binary Image Conversion

Z = im2bw( k );imshow(z);

Here image will not be displayed

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To Display Binary Images

BW = imread('circles.png');

imshow(~BW)imshow(BW) imshow(BW,[1 0 0; 0 0 1])

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Conclusion

Digital Image Processing using MATLAB is very interactive ,allows formulatingsolutions to many technical problems ,thoseinvolving Matrix Representations in fractionof time .

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Queries ?

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THANKS

To

Medha 2k7