Sir I'm working a current project image process or image data acquistion my problem is i have to identify a color red and green when it pass to a live web cam or take a snapshot and i'm confused about the rgb color in matlab ex. if(rgb == red)

Sir I'm working a current project image process or image data acquistion my problem is i have to identify a color red and green when it pass to a live web cam or take a snapshot and i'm confused about the rgb color in matlab ex. if(image == red) disp ('red'); if(image == green) disp ('green'); else ......

[Julius MANILA]

function pbStart_Callback(hObject, eventdata, handles) % hObject handle to pbStart (see GCBO) % eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) if ~isfield(handles, 'vid') warndlg('Please do the preview first!'); return; end vid=handles.vid; vid.FramesPerTrigger = 1; vid.ReturnedColorspace = 'rgb'; triggerconfig(vid, 'manual'); vidRes = get(vid, 'VideoResolution'); imWidth = vidRes(1); imHeight = vidRes(2); nBands = get(vid, 'NumberOfBands'); hImage = image(zeros(imHeight, imWidth, nBands), 'parent', handles.axPreview) preview(vid, hImage); handles.vid=vid; guidata(hObject, handles);

% prepare for capturing the image preview start(vid); % pause for 3 seconds to give our webcam a "warm-up" time pause(3); % do capture! trigger(vid); % stop the preview % stoppreview(vid); % get the captured image data and save it on capt1 variable

% now write capt1 into file named captured.png while(vid.FramesAcquired <= 500)%run time =500/fps

data = getsnapshot(vid);

r= imsubtract(data(:,:,1),rgb2gray(data));

r = medfilt2(r, [4 4]);

red = im2bw(r,0.17);

R = sum(red(:));

end

if(R > 0) % display red if red color is being detected count = str2num(get(handles.numred, 'String')); count = count + 1; set(handles.numred, 'String', num2str(count));

else count = str2num(get(handles.numgreen, 'String')); count = count + 1; set(handles.numgreen, 'String', num2str(count));

end

delete(vid); guidata(hOject,handles); %Ineed to detect red and green color on this gui please help

Answer 1

[R. B.K.]

I think you should read Image Types for better understanding on rgb image in matlab.

Matlab splits red channel, green channel and blue channel in a m-by-n-by-3 data array where m and n are width and height. For example:

rgbImage = imread('yellowlily.jpg'); % Read image
redChannel = rgbImage(:,:,1); % Red channel
greenChannel = rgbImage(:,:,2); % Green channel
blueChannel = rgbImage(:,:,3); % Blue channel

[Julius MANILA]

Sir read about this i have only 3 separate channel but it does answer how can return this channel to identify if it is red or green please give me an exam i will send you a link about my project https://www.youtube.com/watch?v=TI61dQbY4lU please help thanks to you sir R.b.k

Answer 2

[Jan]

It is unlikely that you get a 100% signal for the red channel. So better convert the RGB image to HSV colors and check with a certain tolerance.

[Julius MANILA]

Sir read about this i have only 3 separate channel but it does answer how can return this channel to identify if it is red or green please give me an exam i will send you a link about my project https://www.youtube.com/watch?v=TI61dQbY4lU please help thanks to you sir jan simmon

[Julius MANILA]

function pbStart_Callback(hObject, eventdata, handles) % hObject handle to pbStart (see GCBO) % eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) if ~isfield(handles, 'vid') warndlg('Please do the preview first!'); return; end vid=handles.vid; vid.FramesPerTrigger = 1; vid.ReturnedColorspace = 'rgb'; triggerconfig(vid, 'manual'); vidRes = get(vid, 'VideoResolution'); imWidth = vidRes(1); imHeight = vidRes(2); nBands = get(vid, 'NumberOfBands'); hImage = image(zeros(imHeight, imWidth, nBands), 'parent', handles.axPreview) preview(vid, hImage); handles.vid=vid; guidata(hObject, handles);

% prepare for capturing the image preview start(vid); % pause for 3 seconds to give our webcam a "warm-up" time pause(3); % do capture! trigger(vid); % stop the preview % stoppreview(vid); % get the captured image data and save it on capt1 variable

% now write capt1 into file named captured.png while(vid.FramesAcquired <= 500)%run time =500/fps

data = getsnapshot(vid);

r= imsubtract(data(:,:,1),rgb2gray(data));

r = medfilt2(r, [4 4]);

red = im2bw(r,0.17);

R = sum(red(:));

end

if(R > 0) % display red if red color is being detected count = str2num(get(handles.numred, 'String')); count = count + 1; set(handles.numred, 'String', num2str(count));

else count = str2num(get(handles.numgreen, 'String')); count = count + 1; set(handles.numgreen, 'String', num2str(count));

end

delete(vid); guidata(hOject,handles); % I need to detect the red and green color and count them on a static text pls help

Answer 3

[Image Analyst]

See my attached demo for tracking a green Sharpie marker in an image. You can easily adapt it to find red.

See other color segmentation methods and demos in my File Exchange: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862&sort=downloads_desc

[Julius MANILA]

Sir read about this i have only 3 separate channel but it does answer how can return this channel to identify if it is red or green please give me an exam i will send you a link about my project https://www.youtube.com/watch?v=TI61dQbY4lU please help thanks to you sir image analyst

[Image Analyst]

I don't understand the grammar of the post so I have no idea what you're asking, if anything. I also don't know what I'm supposed to do with the video. Have an English speaker review the post and ask a specific question.

[Julius MANILA]

Sir Image Analyst this a example code for detecting a red color only

v= videoinput(‘winvideo’,1,’YUY2_320x240′);

set(v,’ReturnedColorSpace’,’rgb’);

set(v,’TriggerRepeat’,Inf);

figure;

set(gcf,’doublebuffer’,’on’);

start(v)

while(v.FramesAcquired<=500)%run time =500/fps

data = getsnapshot(v);

r= imsubtract(data(:,:,1),rgb2gray(data));

r = medfilt2(r, [4 4]);

red = im2bw(r,0.17);

R = sum(red(:));

subplot(1,2,1);imshow(data);

subplot(1,2,2);imshow(red);

if(R > 0) % display red if red color is being detected

disp(‘RED’);

else if ()% * this is the part that i'm confuse about*

disp(‘GREEN’);

end

end

stop(v);

I need to detect also the color green. I hope You'll understand by now

thanks again Sir Image Analyst

[Image Analyst]

So what's the problem? Does it work or not? You forgot to attach the video so I can't test it.

[Julius MANILA]

it does work on the red color only but i need also to identify the green and the blue when i snap shot on my camera please help

[Image Analyst]

Basically try the same thing except instead of this

r= imsubtract(data(:,:,1),rgb2gray(data));

use channels 2 and 3:

r= imsubtract(data(:,:,2),rgb2gray(data));  
r= imsubtract(data(:,:,3),rgb2gray(data));

You'll probably want to compute rgb2gray(data) in advance so you're not doing it 3 times.

[Julius MANILA]

Sir Image Analyst this a link to a youtube video that i hoping that will be the output of my program except for the shape the demostrate in this video

please watch this hoping for your feedback https://www.youtube.com/watch?v=TI61dQbY4lU