Linear contrast stretch to image?

Hi, I am very new to image manipulation and MatLab.

I am asked to perform a linear contrast stretching on an image using the defined function histogramlinearstretch. How would I do this? I am not sure what "m" is in this case, and how to apply the function to the image.

Unfortunately I can't upload a .raw file, so the code will show an error, but please ignore that.

infrared = fread( fopen( 'band.raw', 'r'), [1000 1000], '*uint8')';
figure('Renderer', 'painters'),colormap('gray')
imshow(infrared)

function a = histogramlinear(m)
    minimum_pixel = double(min(min(m)));
    maximum_pixel = double(max(max(m)));
    a = uint8(255*(double(m) - minimum_pixel)/(maximum_pixel-minimum_pixel));
end

%Display the image and plot the histogram
colormap('gray'),

Answer 1

[Sarvesh Kale]

Hi Macy,

You are trying to perform linear contrast stretch to an image, so basically you are trying to map your intensities [xmin xmax] in image pixels 0 to 255 range which is done by your function histogramlinear, this function will receive the image you are trying to do contrast stretching on an example snippet is shown below

img1 = imread('pout.tif');

minimum_pixel = double(min(min(img1))); % give minimum pixel intensity
maximum_pixel = double(max(max(img1))); % give maximum pixel intensity
img2 = uint8(255*(double(img1) - minimum_pixel)/(maximum_pixel-minimum_pixel));

figure ;
title('Contrast adjustment by linear scaling')
imshow([img1,img2])

You can see that the left image transforms to right image from your code, I hope this helps, please accept the answers if it does

Thank you .