MATLAB: Does the code not work in home edition

home editionImage Processing Toolbox

Hello, this is a continuation of my previous question https://se.mathworks.com/matlabcentral/answers/311565-why-do-i-get-undefined-function-blkproc-in-home-edition

Like I said, my 11 year old program still worked in the trial version, with all the addons, but not in the home edition. From the answers I learned that my program used a command from a certain addon, Image Processing Toolbox, which I have then purchased. Now I get different errors. Can you tell me just by looking at the red error text what is the problem?

BLOCKPROC encountered an error while evaluating the user-supplied function handle, FUN.
The cause of the error was:
Undefined function 'le' for input arguments of type 'struct'.
Error in AdaptivelyThreshold (line 9)
    s1=find(I<=T);
Error in blockprocFunDispatcher (line 13)
        output_block = fun(block_struct);
Error in blockprocInMemory (line 80)
[ul_output fun_nargout] = blockprocFunDispatcher(fun,block_struct,...
Error in blockproc (line 242)
    result_image = blockprocInMemory(source,fun,options);
Error in imOevelse8_1jeppe (line 14)
BW=blockproc(dI,[N,N],@AdaptivelyThreshold); %Blokvis processing med funktionen AdaptivelyThreshold

Best Answer

It passes a structure so you need to extract the data field. Change AdaptivelyThreshold (line 9) to this:

    s1=find(I.data<=T);

Be aware that s1 can be a vector and I.data is a 2D array so you should probably do this:

    [rows, columns] = find(I.data <= T);

Related Solutions

MATLAB: Image thresholding for different regions of the image

Using some sort of adaptive contrast adjustment (such as adapthisteq) or thresholding (such as adaptthresh) should help.

Using the image in your screenshot (which may well be different from your original image, in future attach the raw image), this seems to work reasonably well:

img = rgb2gray(imcrop(imread('threshold example.PNG'), [40 15 926 180])); %load screenshot, crop to input image, convert to greyscale
imshow(imbinarize(img, 'adapt', 'Sensitivity', 0.61));

MATLAB: Integers can only be combined with integers of the same class, or scalar doubles

You have to case "Image" as double in

Threshold= conv2(Image, AverageMask);

By the way, don't use "Image" as a variable name since it's so close to the built-in function called "image" and you risk using the wrong one with a simple typo. There were a number of other errors in there, which I fixed for you:

clc;  % Clear command window.
clear;  % Delete all variables.
close all;  % Close all figure windows except those created by imtool.
imtool close all;  % Close all figure windows created by imtool.
workspace;  % Make sure the workspace panel is showing.
fontSize = 16;
% Global Thresholding of an unsuitable image. In comparison, the same
% image is thresholded in an Adaptive manner.
grayImage= imread('cameraman.tif');
clear ball;
% Display the original image (normalized to the range 0-64)
colormap(gray);
subplot(2, 2, 1); 
% Reduce the contrast.
imshow(round(grayImage/4));
title('(a) The Original image', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Let's compute and display the histogram.
[pixelCount, grayLevels] = imhist(grayImage);
subplot(2, 2, 2); 
bar(pixelCount);
grid on;
title('(b) Histogram of original image', 'FontSize', fontSize);
xlim([0 grayLevels(end)]); % Scale x axis manually.
% Perform Global thresholding with a threshold of 130
Tg= 130;
GlobalThresholded = grayImage > Tg;
colormap(gray);
subplot(2, 2, 3); 
imshow(GlobalThresholded);
title('(c) Globally Thresholded image, Tg=130', 'FontSize', fontSize);
% Perform an Adaptive Thresholding: average over a neighborhood of 61x61
AverageMask= ones(61, 61) / (61^2);
Threshold = conv2(double(grayImage), AverageMask, 'same');
% Get the image that is 6 above the deviation from the local mean.
ThresholdMask = double(grayImage) - Threshold + 6;  % Why 6????
AdaptiveThresholded = ThresholdMask > 0;
subplot(2, 2, 4); 
imshow(AdaptiveThresholded);
title('(d) Adaptive Thresholded Image', 'FontSize', fontSize);

By the way, do you know that CLAHE is implemented by MATLAB's Image Processing Toolbox. You can use the function adapthisteq() to do essentially what you tried to, and do a better job of it.

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