How to convert an image from 3d to 2d?

I got following error while processing it.

Error using ==> iptcheckinput Function HISTEQ expected its first input, I, to be two-dimensional.

      Error in ==> histeq at 71
         iptcheckinput(a,{'uint8','uint16','double','int16','single'}, ...

      Error in ==> Project_Stage_1 at 9
      I2 = histeq(f); %improve contrast

[Matt J]

Well, why doubt the error message? Is f two-dimensional or isn't it?

[Richa Nayak]

The image is 3d i think. that is f. I need to convert it to 2d for running the prog apparantly. I cant upload the image here. ne suggestions?

Answer 1

[Image Analyst]

You can't do it on a color image. You can do it on each color channel, one at a time,

% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);

or convert to hsv colorspace

% Extract the individual red, green, and blue color channels.
hsv = rgb2hsv(rgbImage);
hChannel = hsv (:, :, 1);
sChannel = hsv (:, :, 2);
vChannel = hsv (:, :, 3);

and do it on the v channel - this is the best way and it avoids severe color artifacts like you'll have doing it in RGB space.