Prof. Muhammad Saeed

With

Contents

MS Image Processing 2

Fundamentals

Read:kid=imread('kid02.jpg');

Display:figure; imshow(kid);imshow(kid, [low high]);

Image Info:info=imfinfo('kid02.jpg'); orwhos kid;

Filename: [1x64 char] FileModDate: '24-Oct-2011 16:51:40' FileSize: 48613 Format: 'jpg' FormatVersion: ‘' Width: 344 Height: 401 BitDepth: 24 ColorType: 'truecolor' FormatSignature: '' NumberOfSamples: 3 CodingMethod: 'Huffman' CodingProcess: 'Sequential' Comment: {} ImageDescription: 'OLYMPUS DIGITAL CAMERA’ Make: 'OLYMPUS OPTICAL CO.,LTD' Model: 'C4040Z' Orientation: 1 Software: 'v552u-A80' DateTime: '2001:01:02 06:01:42' YCbCrPositioning: 'Co-sited' DigitalCamera: [1x1 struct] UnknownTags: [3x1 struct]

[r c]=size(kid);

Introduction to Image:Image as matrixImage TypeImage ClassImage SizeImage Resolution

MS Image Processing 3

Write on Disk:imwrite(kid,'kid02gray.png');imwrite(kid,'kid02gray.jpg’,’quality’,75); % (0:100)imwrite(kid,'kid02gray.tif’,’compression’,’none’,‘resolution’,[m n]); % (packbits, ccitt), (dpi)Conversion of Class and Type:B=logical(A);C=im2bw(T);D=mat2gray(P,[Pmin Pmax]);F=Im2double(g);G=im2uint8(H);

Image Arithmatic:C=imadd(A,B); C=imsubtract(A,B);C=immultiply(A,B); C=imdivide(A,B);C=imabsdiff(A,B); C=imcomplement(A);

C=imlincomb(A,B);MS Image Processing 4

Image Flipping and Sizing:C=F(end:-1:1,:);C=F(:, end:-1:1);C=F(1:2:end,1:2:end);

Color Image to Gray:C=rgb2gray(F);

Image Cropping:C=F(50:end-20, 50:end-40);

Pixel Information Direct:impixelinfo;imdistline;

MS Image Processing 5

Spatial Domain Processing

Intensity Transformation:S=imadjust(A,[inL inH],[outL outH],gamma);S=imadjust(A,[0 1],[1 0]); %image complementS=imadjust(A,[],[],2); Logarithmic and Contrast Stretching Transform

i)ii)

HistogramsH=imhist(A,nbins);H=imhist(A,nbins)/numel(A); % normalized histogramH=histeq(A,nbins); % histogram equalization

))(1log(* AdoublecS

MS Image Processing 6

Linear Spatial Filtering:C=imfilter(A, w, ‘mode’, ‘boundary opts’, ‘size opts’);

% w is the filter% modes= corr, conv% boundary options=p, replicate, symmetric, circular% size options=full, same

w=fspecial(‘type’, parameters);

type parameters defaultaverage [r, c] 3x3disk R (radius, square of 2R+1) 5gaussian [r, c],sig(STD) 3x3, 0.5laplacian(3x3) alpha(0-1) 0.5log(laplacian [r, c],sig(STD) 5x5, 0.5 of a gaussian)motion len(pixel), theta(degrees)CCW 9, 0prewitt(3x3, verticle gradient, transpose for horizontal)sobel(3x3, verticle gradient, transpose for horizontal)unsharp(3x3) alpha(0-1) 0.2

7MS Image Processing

Sobel:

101

202

101

I, and II,

121

000

121

Mathematical Form of Filters:

Prewitt:

111

000

111

I, and II,

101

101

101

Gaussian Filter:

Laplacian Filter:

Unsharp Filter:

8MS Image Processing

Linear Spatial Filters in action:kid=imread('kid02.jpg');w=[1 1 1;1 -8 1;1 1 1];C=imfilter(kid, w,'corr', 'replicate', 'same');subplot(1,2,1);imshow(kid);title('Original','FontSize',20);subplot(1,2,2);imshow(4*C);title(mat2str(w),'FontSize',20);

111

181

1111.

2. chboard=(checkerboard(90)>0.1);w=[0 1 0;1 -4 1;0 1 0];C=imfilter(chboard, w,'conv','replicate', 'full');subplot(1,2,1);imshow(chboard);title('Original','FontSize',20);subplot(1,2,2);imshow(4*C);title(mat2str(w),'FontSize',20);

010

141

010

3. kid=imread('kid02.jpg');w=fspecial('average',[10 10]); C=imfilter(kid, w,'conv','replicate','same'); subplot(1,2,1);imshow(kid);title('Original','FontSize',20);subplot(1,2,2);imshow(C);title('Average','FontSize',20);

average

9MS Image Processing

4. kid=imread('kid02.jpg');w=fspecial('disk', 6); C=imfilter(kid, w); subplot(1,2,1);imshow(kid);title('Original','FontSize',20);subplot(1,2,2);imshow(C);title('Disk','FontSize',20);

disk

5. kid=imread('kid02.jpg');w=fspecial('gaussian',10, 0.8); C=imfilter(kid, w);subplot(1,2,1);imshow(kid);title('Original','FontSize',20);subplot(1,2,2);imshow(C);title('Gaussian','FontSize',20);

gaussian

6. kid=imread('kid02.jpg');w=fspecial('laplacian', 0.6); C=imfilter(kid, w,'conv','replicate','same'); subplot(1,2,1);imshow(kid);title('Original','FontSize',20);subplot(1,2,2);imshow(6*C);title('Laplacian','FontSize',20);

laplacian

10MS Image Processing

7. kid=imread('kid02.jpg');w=fspecial('log',5,0.2); C=imfilter(kid, w,'conv','replicate','same'); subplot(1,2,1);imshow(kid);title('Original','FontSize',20);subplot(1,2,2);imshow(4*C);title('Log','FontSize',20);

log

8. kid=imread('kid02.jpg');w=fspecial('motion',20,10); C=imfilter(kid, w);subplot(1,2,1);imshow(kid);title('Original','FontSize',20);subplot(1,2,2);imshow(C);title('Motion','FontSize',20);

motion

9. kid=imread('kid02.jpg');w=fspecial('prewitt');C=imfilter(kid, w);subplot(1,2,1);imshow(kid);title('Original','FontSize',20);subplot(1,2,2);imshow(C);title('Prewitt','FontSize',20);

prewitt

11MS Image Processing

10. kid = imread('kid02.jpg');w = fspecial('sobel');C=imfilter(kid, w);subplot(1,2,1);imshow(kid);title('Original','FontSize',20);subplot(1,2,2);imshow(C);title('Sobel','FontSize',20);

sobel

11. kid = imread('kid02.jpg');w = fspecial('unsharp',0.5); C=imfilter(kid, w);subplot(1,2,1);imshow(kid),title('Original','FontSize',20);subplot(1,2,2);imshow(C),title('Unsharp','FontSize',20);

unsharp

12. kid=imread('kid02Gray.jpg');C=filter2('sobel',kid);subplot(1,2,1);imshow(kid);title('Original','FontSize',20);subplot(1,2,2);imshow(C,[]);title('Filtered Red','FontSize',20);

filter2

12MS Image Processing

13. kid=imread('kid02darkgray.jpg');subplot(2,2,1);

imshow(kid);title('Original','FontSize',20);subplot(2,2,2);

imhist(kid,64);title('Histogram I','FontSize',20);subplot(2,2,3);

heq=histeq(kid,64); imshow(heq,[]);title(‘Equalized','FontSize',20);

subplot(2,2,4);imhist(heq,64); title('Eq. Histogram','FontSize',20);

histeq

13MS Image Processing

Nonlinear Spatial Filters:

kid=imread('kid02darkgray.jpg');kidfilt=ordfilt2(kid,25,true(7));subplot(1,2,1);imshow(kid); title('Original','FontSize',20);subplot(1,2,2);imshow(kidfilt); title(‘Filtered','FontSize',20);

1) ordfilt2 (f, order, domain)

kid=imread('kid02Gray.jpg');kidnoise=imnoise(kid,'salt & pepper',0.2);kid2=medfilt2(kidnoise,[5 5],'symmetric'); %symmetric, zeros, indexed%kid2=medfilt2(kid2,'symmetric');subplot(1,2,1);imshow(kidnoise);title('Original','FontSize',20);subplot(1,2,2);imshow(kid2);title('Filtered','FontSize',20);

2) medfilt2 (f, ’symmetric’)

14MS Image Processing

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15MS Image Processing