Why do I get the following error when I am trying to run my code - Undefined function 'imadjust' for input arguments of type 'uint8'.

Why do I get the following error when I am trying to run my code - Undefined function 'imadjust' for input arguments of type 'uint8'.

[Stephen23]

Guessing: because you do not have the Image Processing toolbox installed and/or no valid license for it.

Answer 1

[Mathieu NOE]

hello

alternative code if you don't have access to the Image Processing toolbox

I = imread('your image.jpg'); % Example  image

% Equivalent to imadjust(I, [0.2 0.8], [0 1], 1)
J = imadjust_alternative(I, [0.2 0.8], [0 1], 1);


% Display side-by-side
figure;
subplot(1,2,1);
imshow(I);
title('Image I');

subplot(1,2,2);
imshow(J);
title('Image J');


function J = imadjust_alternative(I, inRange, outRange, gamma)
    % imadjust_alternative - Adjust image intensity values without imadjust
    %
    % I        : Input image (grayscale or RGB, uint8/uint16/double)
    % inRange  : [low_in high_in] input intensity range (default: [min(I) max(I)])
    % outRange : [low_out high_out] output intensity range (default: [0 1])
    % gamma    : Gamma correction value (default: 1)

    % inRange and outRange work like in imadjust.
    % Gamma correction is applied after normalization.
    % Works for grayscale and RGB images.
    
    % Convert to double for calculations
    I = im2double(I);
    
    % Default parameters
    if nargin < 2 || isempty(inRange)
        inRange = [min(I(:)) max(I(:))];
    end
    if nargin < 3 || isempty(outRange)
        outRange = [0 1];
    end
    if nargin < 4 || isempty(gamma)
        gamma = 1;
    end
    
    % Clip input values to inRange
    I = max(min(I, inRange(2)), inRange(1));
    
    % Normalize to [0,1]
    I_norm = (I - inRange(1)) / (inRange(2) - inRange(1));
    
    % Apply gamma correction
    I_gamma = I_norm .^ gamma;
    
    % Scale to output range
    J = outRange(1) + I_gamma * (outRange(2) - outRange(1));
    
    % Preserve original class
    if isinteger(I)
        J = im2uint8(J);
    end
end

[Walter Roberson]

Hmmm.... the code will do odd things if inRange happens to be integer data type.