how can i detect triangle

how can i detect green colour triangle from pic

[Muhammad Usman Saleem]

is this image?

[Ahmad Jadoon]

yes

Answer 1

[Image Analyst]

You can segment out that green triangle using either color or shape - your choice. I'm attaching demos for each. Feel free to adapt as needed.

[Ahmad Jadoon]

i use this coding but it detect square ,.. plz help how can i detect triangle using this coding

clear all

clc

Img =imread('shapes.png');

subplot(2,2,1)

imshow(Img) % RGB Image

subplot(2,2,2)

[Height Width]=size(Img(:,:,2));

for i=1:Height

for j=1:Width

    if Img(i,j,1:2)<115
Triangle(i,j)=Img(i,j);

else Triangle(i,j)=256;

end end end

imshow(Triangle) % Detected Triangle

[Image Analyst]

Don't use for loops and simply vectorize it. Get rid of the size() and two for loops and simply have this:

% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);
% Get pixels that are greener than they are red or blue.
Triangle = greenChannel  > redChannel & greenChannel > blueChannel;

[Ahmad Jadoon]

thanks sir

Answer 2

[Muhammad Usman Saleem]

try these links

http://www.mathworks.com/matlabcentral/answers/110855-how-to-detect-the-shape-in-matlab

http://www.mathworks.com/matlabcentral/answers/116793-how-to-classify-shapes-of-this-image-as-square-rectangle-triangle-and-circle

http://www.mathworks.com/matlabcentral/answers/34173-detect-shape-in-image

http://shapedetection.blogspot.com/

or use Shape Recognition

[Ahmad Jadoon]

i use this coding but it detect square ,.. plz help how can i detect triangle using this coding

clear all

clc

Img =imread('shapes.png');

subplot(2,2,1)

imshow(Img) % RGB Image

subplot(2,2,2)

[Height Width]=size(Img(:,:,2));

for i=1:Height

for j=1:Width

    if Img(i,j,1:2)<115

Triangle(i,j)=Img(i,j);

else Triangle(i,j)=256;

end end end

imshow(Triangle) % Detected Triangle