Drawing a Cirlce on an Image using viscircles()

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Ash4Matlab
Ash4Matlab am 11 Jun. 2020
Kommentiert: KSSV am 12 Jun. 2020
Dear all,
I am trying to put a circle at the center of an image using the folowing code.
clear;clc;
Image = imread('cameraman.tif');
M = 128; % cirlce array length
D = 0.5; % diameter
Pupil = (-fix(M/2):fix((M-1)/2));
figure(1)
imshow(Image)
viscircles([xPupil' xPupil'],D/2.*ones(M,1))
But it looks a pipe from the left corner of the image. I am using 2019a version of Matlab.
I would aprreciate if someone can fix this issue.
Thanks in advance.

Antworten (1)

KSSV
KSSV am 11 Jun. 2020
You can draw circle using the below code if center C and radius R of the circle are known.
C = rand(1,2) ; % center of cricle
R = 1. ; % radius of the circle
m = 100 ;
th = linspace(0,2*pi,m) ;
x = C(1)+R*cos(th);
y = C(2)+R*sin(th) ;
plot(x,y)
  2 Kommentare
Ash4Matlab
Ash4Matlab am 12 Jun. 2020
Hello KSSV,
Thanks for the answer.
Actually I wanted to apply a circular mask on an image and depict that circle (or mask) on the image. For which as far as I know, viscirlces() shouLd work, but I am unable to put the image and the circle togather.
KSSV
KSSV am 12 Jun. 2020
Why not use the above code, provide center and radius, you can plot circle on the image. To draw a mask, get the indices lying inside the circle using inpolygon and make those indices zero.

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