Error , find entropy of 3d volumetric image on GLCM features ?

I will find GLCM feature. But error follow as:

b=niftiread("D:\DATASET\Task01_BrainTumour\imagesTr\BRATS_001.nii");
b1=b(:,:,:,1);
cmap = copper(256);
recolored_image = rgb2gray(b1, cmap);

error as following;

Error using rgb2gray

Too many input arguments.

Answer 1

[Walter Roberson]

rgb2gray() has never supported more than one input, and has never supported recoloring images.

rgb2ind supports passing in a colormap. You could recolor an image by using

ind = rgb2ind(b1, cmap);
recolored_image = ind2rgb(ind, cmap);

Answer 2

[Abderrahim. B]

Hi!

b1 is not truecolor image that is a m-by-n-by-3 numeric array. b1 in your case is a m by n by l by 1 (4 D array). use reshape to deal with this.

Hope this helps

[Walter Roberson]

This is a potential problem -- but it would not affect the fact that rgb2gray does not accept two parameters.

[Abderrahim. B]

How can I forget that rgb2gray accept only one input argument! Thanks @Walter Roberson

[Hla Hla]

Dear sayar, i run above the code.

ind = rgb2ind(b1, cmap);
recolored_image = ind2rgb(ind, cmap);

Error occupy followas:

Error using rgb2ind>parse_inputs (line 145)

RGB image has to be M-by-N-by-3 array.

Error in rgb2ind (line 53)

[RGB,m,dith] = parse_inputs(varargin{:});

[Walter Roberson]

What is size(b) after you read it?