How to set radii in imfindingcircles function?

Question

Elisa 2024-7-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2138396-how-to-set-radii-in-imfindingcircles-function

回答： Deepak 2024-7-18

dear all, i'm trying to create a mask for this image based on the fuction imfindingcircles. I tried setting different thresholds but I didn't get the rigth result. Can anybody help me? than I would like to set NaN to the mask. Thank you in advance!

clear all
close all
clc
A= imread('image_1567.png');
[rows, columns, numberOfColorChannels] = size(A)
%imshow(A)
[centers,radii] = imfindcircles(A,[50 100],Sensitivity=0.9);
mask = circles2mask(centers,radii,size(A));
figure
montage({A,mask})
A(~(A == mask)) = nan

2 个评论
显示无隐藏无

Shantanu Dixit 2024-7-18

Hi Elisa, can you share the image you are working on?

Elisa 2024-7-18

image_1567.png

yes sure, it was missed, sorry

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Deepak 2024-7-18

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2138396-how-to-set-radii-in-imfindingcircles-function#answer_1487486

在 MATLAB Online 中打开

Hi,

The radius range set in the “imfindcircles” method is "[50 100]". It needs to be in the range "[500 650]" to detect the circle present in the PNG image provided by you.

Also, the sensitivity parameters need to be set to “0.95” instead of “0.9” due to the low contrast difference between black background and grey circle.

Here is the updated code snippet that will detect the circle to mask –

[centers,radii] = imfindcircles(A,[500 650],Sensitivity=0.95);

Attaching the documentation of “imfindcircles” for reference –

https://www.mathworks.com/help/images/ref/imfindcircles.html