error in rgb2gray and imshow

a=imread('C:\Users\amirg\OneDrive\Pictures\butterfly.jpg');

gray=rgb2gray(a);

[row,col]=size(a);

subplot(3,3,1);

imshow(gray);

title('original image');

c=zeros(row,col,8);

for k=1:8

for i=1:row

for j=1:col

c(i,j,k)=bitget(a(i,j),k);

end

end

subplot(3,3,k+1);

imshow(c(:,:,k));

title(['Bit plane ',num2str(k-1)]);

end

error

Attempt to execute SCRIPT gray as a function:

C:\Users\amirg\OneDrive\Documents\MATLAB\gray.m

Error in images.internal.imageDisplayValidateParams (line 45)

common_args.Map = gray(256);

Error in images.internal.imageDisplayParseInputs (line 78)

common_args = images.internal.imageDisplayValidateParams(common_args);

Error in imshow (line 240)

images.internal.imageDisplayParseInputs({'Parent','Border','Reduce'},preparsed_varargin{:});

Error in plane (line 5)

imshow(gray);

Answer 1

[Bjorn Gustavsson]

It seems you have named a script or function gray.m in your C:\Users\amirg\OneDrive\Documents\MATLAB\ directory. That will cause problems, since this is the file matlab will find first when you call gray and expect to get the call to the built-in function gray. Check which order you have the gray-files like this:

which gray -all

In order to resolve this naming-conflict, you will have to rename your gray-file to something like my_gray.m. That way it will not shadow the built-in function.

One thing you might consider doing is to put all your files to the end of matlab's search-path. That way you will not break the functionality of matlab and its built-in functions - and you will rapidly realise when you've managed to name one of your files to something already used by matlab.

HTH

[Krithika G SASTRA]

thanks a lot your solution solve my problem

Answer 2

[Image Analyst]

gray() is a function used to build a gray scale colormap. Never use it, or any other built-in functions, as names for your variables.

Also if you have your own functions, like in this case, it could cause problems. Rename your gray.m to some other name.

It's best to use descriptive variable names, instead of single letters like a and c, lest your code look like an impenetrable alphabet soup mess of a program that's hard to read and maintain.

Fix:

rgbImage=imread('peppers.png');
grayImage=rgb2gray(rgbImage);
[rows, columns] = size(rgbImage);
subplot(3,3,1);
imshow(grayImage);
title('original image');
bitPlaneImage = zeros(rows,columns,8);
for bitIndex = 1 : 8
    for row=1:rows
        for col=1:columns
            bitPlaneImage(row,col,bitIndex)=bitget(rgbImage(row,col),bitIndex);
        end
    end
    subplot(3,3,bitIndex+1);
    imshow(bitPlaneImage(:,:,bitIndex));
    title(['Bit plane ',num2str(bitIndex-1)]);
    drawnow; % Force it to paint screen immediately.
end

[Krithika G SASTRA]

thanks a lot your solution solve my problem