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eliminating a color in image

asked 2018-02-03 04:00:55 -0500

arh24 gravatar image

updated 2018-02-03 05:18:06 -0500

Hi i wanted to eliminate gray color from my image, i just need black or white

So i used this code,but in beagle bone black and in some computers, code crashes but in my laptop it works fine what is happening?


typedef cv::Point3_<uint8_t> Pixel;
 for (Pixel &p : cv::Mat_<Pixel>(frame))
         if(p.x<127 ||p.y<127 ||p.z<127 )
                p.x = 0;
                p.y = 0;
                p.z = 0;

gives me this error: OpenCV Error: Bad argument (The total number of matrix elements is not divisible by the new number of rows) in reshape

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"compilers give me this error" ? that's not a compiler error

a good idea is to split frame and use threshold method : threshold(frame,frame,127,255,THRESH_TOZERO_INV )

LBerger gravatar imageLBerger ( 2018-02-03 04:18:30 -0500 )edit

you are right not a compiler error

arh24 gravatar imagearh24 ( 2018-02-03 05:17:29 -0500 )edit

" i wanted to eliminate gray color from my image, i just need black or white" -- that's not really, whatyour code is doing, in the 1st place.

berak gravatar imageberak ( 2018-02-03 05:22:20 -0500 )edit

my input image has only white black and gray colors, so under 127 will eliminate gray

arh24 gravatar imagearh24 ( 2018-02-04 05:25:39 -0500 )edit

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answered 2018-02-03 05:20:31 -0500

berak gravatar image

please don't write per-pixel loops, when using opencv.

the problem in your case seems to be, that your input frame is grayscale(CV_8UC1), but your code assumes CV_8UC3

what you should use instead is threshold , which is type-safe, faster, and less error-prone, like:

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Asked: 2018-02-03 04:00:55 -0500

Seen: 69 times

Last updated: Feb 03 '18