Problem with a function using rgb2ycbcr

I am trying to do a function using rgb2ycbcr. It converts the image, then shows it up and saves it, but when I call the function, this error appears:

"Subscript indices must either be real positive integers or logicals."

Here's my code:

function x = rgb2yuv( x )
    x = rgb2ycbcr(x)

      imshow(x)
      imwrite(x, 'C:\Users\aaaa\Documents\PDI\Atividade1\imagens\x_rgb2yuv.jpg', 'jpg')
  end

What am I doing wrong?

Answer 1

[sanidhyak]

Hi Brunna,

I too encountered the same issue. This issue arises because the "rgb2ycbcr" function expects the input to be a valid numeric array representing an RGB image. Kindly refer to the below case as an example:

RGB = imread("board.tif");   
YCBCR = rgb2ycbcr(RGB);

Ensure that RGB must be from one of the following formats:

• A c-by-3 colormap, where each row specifies an RGB color value
• An m-by-n-by-3 image matrix

So, to resolve this issue, you need to modify your function as follows:

function x = rgb2yuv(x) 
x = imread(x); % Read the image first 
x = rgb2ycbcr(x); % Convert to YCbCr 
imshow(x); % Display the converted image 
imwrite(x, 'C:/Users/aaaa/Documents/PDI/Atividade1/imagens/x_rgb2yuv.jpg', 'jpg'); % Save the output 
end 

This would ensure that the image is properly read before being processed.

For further reference, kindly refer to the MATLAB documentation below:

• https://www.mathworks.com/help/images/ref/rgb2ycbcr.html