1. Fourth Year – Software Engineering
Image Processing
Fourth Year – Software Engineering
Introduction

2. Reading, writing and displaying images
myImg = imread(’foo.ext’) reads file foo.ext into array myImg, image format is determined by the file extension (jpg, tiff, tif, gif, bmp, png, ...) imwrite(anImg, ’foo.ext’) writes the image anImg to the file foo.ext, where the image format is chosen according to the extension ext. Valid extensions are: tif, tiff, jpg, `` jpeg, gif, png imshow(myImg) displays the image myImg as gray- scale, binary or color image depending on the data type of myImg figure(n) opens a new window with number n, the next

3. Color planes
The green and red color plane of image rgbimage.jpg are swapped: f = imread(’rgbimage.jpg’); red = f(:,:,1); g(:,:,1) = f(:,:,2); g(:,:,2) = red; g(:,:,3) = f(:,:,3); imshow(g);

4. Image Processing Read Image Display image Convert RGB to grayscale
imread(‘path’)
ex:
img=imread('D:\images\sherko.jpg');
Display image
imshow(img);
Convert RGB to grayscale
rgb2gray(img);
figure;
grayscaleimage=rgb2gray(img);
Divide figure into grid
subplot(row,column,location);

5. Image Processing ex: subplot(2,2,1);imshow(img);title('OrignalImage');
subplot(1,2,2);imshow(grayscaleimage);title('GrayScaleImage');
color spaces
RGB
subplot(2,2,1);imshow(img);title('OrignalImage');
subplot(2,2,2);imshow(img(:,:,1));title('RChannelValues');
subplot(2,2,3);imshow(img(:,:,2));title('GChannelValues');
subplot(2,2,4);imshow(img(:,:,3));title('BChannelValues');

6. Image Processing Resize Image imresize(img, scale)
ex:
resizeimage=imresize(img,0.5);
imshow(img);
figure;
imshow(resizeimage);
Imresize(img,[numrow numcolumn]);
[m n ~]=size(img); %color image
resizeimage=imresize(img,[m/2 n/2]);

7. Image Processing Crop Image Write Image
imcrop(img,[xmin ymin width height]);
ex:
croppedimage=imcrop(img,[ ]);
Write Image
imwrite(image,filename,fmt)
imwrite(croppedimage,strcat('D:\images\Mypicture','.bmp'));