Undefined function 'graythresh' for input arguments of type 'uint8'

img1=imread('Counting.jpg');
imshow(img1)

img1=rgb2gray(img1);
imshow(img1)

img2=im2bw(img1,graythresh(img1));
imshow(img2)

img2=~img2;
imshow(img2)

B = bwboundaries(img2);
imshow(img2)
text(10,10,strcat('\color{green}Objects Found:',num2str(length(B))))
hold on

for k = 1:length(B)
    boundary = B{k};
    plot(boundary(:,2), boundary(:,1), 'g', 'LineWidth', 0.2)
end

When I type this in, I get an error saying, "Undefined function 'graythresh' for input arguments of type 'uint8'

Does anybody know why? Help would be greatly appreciated.

Answer 1

[Image Analyst]

You do not have the Image Processing Toolbox installed. Type "ver" on the command line to see what toolboxes you have. imread() and rgb2gray() are both in base MATLAB so that is why you didn't see an error with them even though they were called prior to graythresh().

[Johoon Kim]

Problem solved. Thank you so much!

[madhan ravi]

Accepted answer by madhan ravi since the OP didn’t

[madhan ravi]

+1

Answer 2

[Bassel]

Hello, I have the same problem. although i have installed the "Image Processing Toolbox"

It'll be great if you can help me.

kind regards Bassel

[Image Analyst]

You may have it installed but don't have a license for it, for example you're in a pool of licenses and all the Image Processing licenses are checked out when you try to check one out. What does this show:

>> hasLicenseForToolbox = license('test', 'image_toolbox')  % Check for Image Processing Toolbox.
hasLicenseForToolbox =
     1

As you can see, you should see a 1 if there is a license available.

[minseok kang]

thank you - from south korea