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how separate color image as red ,green and blue

On Programmer » Matlab

1,727 words with 1 Comments; publish: Mon, 28 Apr 2008 02:20:00 GMT; (200156.25, « »)

hi there,

please anyone can help me to find a function that separate

the color image to three red,green and blue .So, I can

take the histogram for each one.

many thanks,huda

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    • "huda nawaf" <halmamory.matlab.todaysummary.com.yahoo.com> wrote in message

      <fbekpe$v4$1.matlab.todaysummary.com.fred.mathworks.com>...

      > hi there,

      > please anyone can help me to find a function that separate

      > the color image to three red,green and blue .So, I can

      > take the histogram for each one.

      > many thanks,huda

      If you have an image say Image_rgb then you can separate the

      colour planes as follows

      Image_red = Image_rgb(:,:,1);

      Image_green = Image_rgb(:,:,2);

      Image_blue = Image_rgb(:,:,3);

      It probably goes without saying that if you view these

      planes they are displayed as greyscale images; I mention

      this, as one previous op was surprised that they did not

      come out as a red, green and blue colour images.

      Bear in mind that when you histogram these images separately

      as you plan to do, you can come to some possibly misleading

      results. For example suppose your result tells you you that

      25% of your pixels are full scale green, and 25% are full

      scale red, you can get this either from you having 25% of

      individual pixels being red, and another 25% being green,

      else you can get exactly the same histogramme, if 25% of

      your colour image is yellow, so be aware this can happen. If

      this is a problem, you can generate a normal histogramme for

      the intensity plane, and a two dimensional histogramme which

      has hue on one axis, saturation on the other, and pixel

      count in the z direction.

      Regards

      Dave Robinson

      #1; Mon, 28 Apr 2008 02:22:00 GMT