IMAGE ACQUISITION AND BASIC OPERATION(MATLAB)

IMAGE PROCESSING TOOLBOX

In this lab, we have performed some basic image processing exercise by matlab. The main purpose of this lab is to :

1.       Read and display image

2.       Check how the image appears in the workspace

3.       Perform histogram equalization on the image

4.       Write the image to a disk file

5.       Get information about graphic file

Below is the commands and example output:

>>I = imread (‘pout2.png’)     % Output the array

>>Imshow(I)                          % To display image

Original   'pout2.png'

>>whos    % To see how I is stored in memory

Input and output of 'whos' command

>>figure, imhist(I)    % To display histogram of I in the new figure

Histogram equilization

>>I2 = histeq(I)      %Equalize I and output in new array

>>figure, imshow(I2)    %Display the new equalized image I2.

Equilized   'pout2.png'

>>imwrite(I2, 'pout2.png')      % To write the newly adjusted image I2 back to disk.

>>imfinfo(‘pout2.png’)     % To check the content of newly written file

Check info

Next, we also learn on how to edit image

This command shows original image

>> x = imread ('obama.png');

>> figure,  imshow (x)

The original image

This command functions to convert original image to be gray scaled:

>> x_g = rgb2gray(x);

>> figure, imshow (x_g)

The image has been converted to gray scale

This command allow cropping image:-

>> imshow (x_g' imcrop);

This command function will flip the image:

>> figure(1); image(x)

x(:, :, 1) = fliplr (x(:, :, 1));

x(:, :, 2) = fliplr (x(:, :, 2)); 

x(:, :, 3) = fliplr (x(:, :, 3)); 

figure(2); image(x)

The flipped image

Commands function below will show how an image being flipped vertically and horizontally

>> xMirror = flipdim(x,2);             % horizontal flip

>>  xUpsideDown = flipdim(x,1);  % vertical flip

>> xHorizontalAndVerticalFlip = flipdim (xUpsideDown, 2);  % horizontal and vertical flip

>> subplot(2,2,1), imshow(x)

>> subplot(2,2,2), imshow(xMirror)

>> subplot(2,2,3), imshow(xUpsideDown)

>> subplot(2,2,4), imshow(xHorizontalAndVerticalFlip)

Flipped image in both vertical and horizontal

Image info by using command function >> iminfo(x)