Applying 2D filter on RGB image

Hi all,

I'm having some troubles with applying a vector filter on RGB image, I'm not getting errors but I'm not getting an output which makes sense either. I'm losing at least one of the color channels somehow but I don't know what I'm doing wrong. You can find the application I'm trying to implement in the screenshot attached and I also attach the code to this entry. Looking forward to your help.

For the image I'm trying to upscale, you can get it here.

Thanks in advance

Answer 1

[Subhadeep Koley]

Hi Ozan, the below code might help!

img = imread('kodim07.png');
imshow(img)
img = imresize(img, 2, 'bicubic');
figure
imshow(img)

% define filter kernel
kernel = [1, -5, 20, 20, -5, 1] / 32;

% extracting rgb channels individually
rChannel = img(:, :, 1);
gChannel = img(:, :, 2);
bChannel = img(:, :, 3);

% applying filter to the extracted matrices separately
rChannelNew = filter2(kernel, rChannel);
gChannelNew = filter2(kernel, gChannel);
bChannelNew = filter2(kernel, bChannel);

% concatenate matrices along 3rd dimension
outputImg = cat(3, rChannelNew, gChannelNew, bChannelNew);

% convert the numeric matrix to image
outputImg = mat2gray(outputImg);

figure
imshow(outputImg)