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How to extract red color plane in OpenCV C++

asked 2013-05-18 11:22:41 -0500

Ali Tillawi gravatar image

How to extract red color plane in OpenCV C++?

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answered 2013-05-18 11:50:37 -0500

berak gravatar image

easy!

Mat src=imread("my.png");
Mat planes[3];
split(src,planes);  // planes[2] is the red channel
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Is it applicable for android programming in Java with openCv? if not then can you please suggest me the alternative for this code, Thank you.

khatri.kelash gravatar imagekhatri.kelash ( 2017-01-18 11:40:30 -0500 )edit

Thank you Sir for reply, I managed to write the code, and convert the related 3 channels from matrix form to bitmap form but code is not working. The app just show dialog box [Unfortunaly app has stopped].

khatri.kelash gravatar imagekhatri.kelash ( 2017-01-21 13:08:10 -0500 )edit
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answered 2015-10-06 10:27:00 -0500

Mizux gravatar image

prefer to use void cv::extractChannel (InputArray src, OutputArray dst, int coi )

cv::Mat out; cv::extractChannel(in, out, 0) // Supposing RGB channel with red first out....

src: http://docs.opencv.org/master/d2/de8/group__core__array.html#gacc6158574aa1f0281878c955bcf35642

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answered 2013-05-21 08:09:39 -0500

Ali Tillawi gravatar image

updated 2013-05-21 08:57:53 -0500

Thank you :)

I have used this one and it worked well:

IplImage* frame_r = cvCreateImage(size, IPL_DEPTH_8U, 1);
IplImage* frame_g = cvCreateImage(size, IPL_DEPTH_8U, 1);
IplImage* frame_b = cvCreateImage(size, IPL_DEPTH_8U, 1);

    cvSplit(frame, frame_b, frame_g, frame_r, NULL);
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What you are doing isn't C++ code but using the old C-style API. Keep in mind that the support for the old API will start to get less and less, since people are stimulated to use the newer, more clear C++ interfacing of OpenCV.

StevenPuttemans gravatar imageStevenPuttemans ( 2013-05-21 09:10:51 -0500 )edit

Sir how to subtract among three planes example r-g+b

kamachisundaram gravatar imagekamachisundaram ( 2014-11-20 03:40:28 -0500 )edit

That is just a simple operator. I think you can subtract and add matrices. Have you tried

Mat temp = red - green + blue;

This should work for your needs!

StevenPuttemans gravatar imageStevenPuttemans ( 2014-11-20 03:44:46 -0500 )edit
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Asked: 2013-05-18 11:22:41 -0500

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Last updated: May 21 '13