Can anyone help with this error? (I just want to see the contour of the bluish area at the bottom of the image)

1 view (last 30 days)
close all
clear all
clc
I = imread('frame75.jpg');
imshow(I)
imcontour(I,3)
Error:
Error in imcontour>ParseInputs (line 110)
validateattributes(a,{'uint8','int16','uint16','double','logical','single'}, ...
Error in imcontour (line 40)
[x,y,a,extra_args] = ParseInputs(varargin{:});
Error in contour (line 8)
imcontour(I,3)

Accepted Answer

darova
darova on 1 Jul 2020
Detect blue region properly
I0 = imread('frame75.jpg');
I1 = double(I0);
% colors from blue region
R = [80 50 0];
G = [160 110 70];
B = [180 120 70];
B1 = logical(I1(:,:,1)*0);
% detect regions and merge
for i = 1:length(R)
B0 = abs(I1(:,:,1)-R(i)) < 20 & ...
abs(I1(:,:,2)-G(i)) < 50 & ...
abs(I1(:,:,3)-B(i)) < 50;
B1 = B1 | B0;
end
% B1 = uint8( cat(3,B1,B1,B1) );
imshowpair(I0,B1)
% imshow(B1.*I0)
  12 Comments

Sign in to comment.

More Answers (1)

Ameer Hamza
Ameer Hamza on 27 Jun 2020
You need to specify a single channel image to imcontour(). For example, just provide the blue channel
imcontour(I(:,:,3), 3)
or convert image to grayscale
imcontour(rgb2gray(I), 3)
  1 Comment
muhammad choudhry
muhammad choudhry on 29 Jun 2020
Edited: darova on 1 Jul 2020
Hi,
Hamza please see the attached. I have changed to grey scale function to capture the contour of the injected dye flow but I am also getting the contours of other background is there a way to only capture the dye contour.
here is a code I used!
close all
clear all
clc
%Read the Image
I = imread('frame75.jpg');
I1 = imread('frame80.jpg');
warning('off', 'Images:initSize:adjustingMag');
%Convert to greyscale (contour command works on greyscale images)
img=rgb2gray(I);
img1=rgb2gray(I1);
%Subtraction of the frames
figure()
dif=img-img1;
warning('off', 'Images:initSize:adjustingMag');
imshow(dif)
hold on
% contour of the image
figure()
imcontour(dif,1);

Sign in to comment.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by