Has anyone had any luck using the function detectCircleGridPoints? I can't get it to work and I have the Computer Vision Toolbox installed.

I have a simple calibration pattern that I would like to implement in my code, but I keep getting the following error: Unrecognized function or variable 'detectCircleGridPoints'. I am simply calling this function within my script:

fileName = 'calibration.jpeg';
img = imread(fileName);
I = rgb2gray(img);

patternDims = [9,9]
detectCircleGridPoints(I,patternDims)

What am I doing wrong?

Here is the image by the way:

[Torsten]

Do you have the Computer Vision Toolbox installed and licenced ?

Type

ver

for the toolboxes installed.

[Andrea Labudzki]

Yes I have the toolbox installed and have tried other functions from this toolbox and they have worked without any problems. I know how to check that it is installed, but not how to check that it is licensed, but since other functions work correctly, I believe that it is licensed as well.

[Torsten]

[status,errmsg] = license('checkout','Computer_Vision_Toolbox')

What do you get back for status and errmsg ?

What if you specify an output argument:

imagePoints = detectCircleGridPoints(I,patternDims)

[Andrea Labudzki]

Hmm i guess i dont have the license for it since I got this:

status =

0

errmsg =

'License checkout failed.

License Manager Error -5

Cannot find a license for Computer_Vision_Toolbox.

Troubleshoot this issue by visiting:

https://www.mathworks.com/support/lme/R2021a/5

Diagnostic Information:

Feature: Computer_Vision_Toolbox

License path: /Users/__/Library/Application Support/MathWorks/MATLAB/R2021a_licenses/license_Andreas-MacBook-Pro_1122315_R2021a.lic:/Applications/MATLAB_R2021a.app/licenses/license.dat:/Applications/MATLAB_R2021a.app/licenses

Licensing error: -5,357.'

I am on a student account by the way, maybe that is why. Do you know what I can do to obtain this license?

[Torsten]

To be sure, try the command for a toolbox for which you know you have a licence.

If it is a private MATLAB license you are working with, you will have to contact Mathworks Support Center, I guess.

If it is a campus licence, contact the computing center.

[Andrea Labudzki]

alright, thanks for the advice!

Answer 1

[yanqi liu]

clc; clear all; close all;
fileName = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/864390/image.jpeg';
img = imread(fileName);
I = rgb2gray(img);
I2 = imresize(I, 800/size(I,1), 'bilinear');
im = I2;
I2 = imcomplement(I2);
bw = ~im2bw(I2, 0.6);
bw = bwareaopen(bw, 10);
bw = imfill(bw, 'holes');
bw2 = ~imopen(bw, strel('disk', 3));
patternDims = [9 9];
imagePoints = detectCircleGridPoints(im2uint8(bw2),patternDims,PatternType="symmetric")

imagePoints = 81×2

373.8634 224.8094 374.8543 270.5855 375.4484 315.5516 375.6929 360.0652 375.7049 404.0779 375.3967 448.0973 374.4328 492.8970 373.1154 538.0381 371.4042 584.3329 419.6315 226.0630

J = insertText(im,imagePoints,1:size(imagePoints,1));
J = insertMarker(J,imagePoints,'x',Color="green",Size=5);
imshow(J)
title("Detected a Circle Grid of Dimensions " + mat2str(patternDims))

[Andrea Labudzki]

Okay thank you, I will try this and let you know!

[Andrea Labudzki]

thank you for the comment but i've realized that I have a problem with my license

[Andrea Labudzki]

Hi, I was able to get the function to work but I got the following error: Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other syntax error. To

construct matrices, use brackets instead of parentheses. What can I do to solve it?

[yanqi liu]

yes，sir，may be use the code we discuss，or upload your now code which find errors

[Andrea Labudzki]

okay thank you!