implement imresize function

I want to scale the screen via Nearest Neighbor interpolation without using imresize. The effect of the photo is adjustable. However, the resulting photo is presented in black and white. I want to express the color of the original photo as it is.

function NN = myResizeNN(picture,scale)

I=imread(picture);

a= size(I,1);

b= size(I,2);

IR = round([1:(b*scale)]./scale);

IC = round([1:(a*scale)]./scale);

output = I(:,IR);

output = output(IC,:);

figure(1); imshow(I);title('Before interpolation');

figure(2); imshow(output);title('After interpolation');

NN = [IR,IC];

end

Answer 1

[Vatsal]

Hi,

The provided function does not preserve the color information because the function currently processes only one dimension of the image. Images in MATLAB are 3D matrices, with the third dimension representing color channels (Red, Green, Blue).

Here is a modified function which preserves the color:

function NN = myResizeNN(picture, scale)
    I = imread(picture);
    [a, b, ~] = size(I);
    IR = round([1:(b*scale)]./scale);
    IC = round([1:(a*scale)]./scale);
    output = zeros(length(IC), length(IR), 3, 'like', I);
    for channel = 1:3
        temp = I(:,:,channel);
        output_temp = temp(:,IR);
        output(:,:,channel) = output_temp(IC,:);
    end
    figure(1); imshow(I); title('Before interpolation');
    figure(2); imshow(output); title('After interpolation');
    NN = [IR,IC];
end

I hope this helps!