displaying Images from image array

I have 35 gray images which is stored in "gray" variable. I want to display all these images using imshow one by one. The problem is I am getting error.

Gray variable size =35*1080*1920

imshow(Gray(1:1,:,:))

Error using images.internal.imageDisplayValidateParams>validateCData

Multi-plane image inputs must be RGB images of size MxNx3.

Error in images.internal.imageDisplayValidateParams (line 30)

common_args.CData = validateCData(common_args.CData,image_type);

Error in images.internal.imageDisplayParseInputs (line 79)

common_args = images.internal.imageDisplayValidateParams(common_args);

Error in imshow (line 253)

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

Answer 1

[Dyuman Joshi]

Maybe size is the problem, try reshaping the size of the array and then using imshow()

in=rand(35,1080,1920);
out=in(1,:,:);
size(out)

ans = 1×3

1 1080 1920

out=permute(out,[2 3 1]);
size(out)

ans = 1×2

1080 1920

imshow(out)

[Vivek Raj]

Thanks a lot but for curiosity if i am writing

out=in(1,:,:);% just to know the difference between 1*1080*1920 and 1080*1920 and why its not working
imshow(out)

[Dyuman Joshi]

The difference is that 1x1080x1920 is a 3D array whereas 1080x1920 is a 2D array.

As to why it's not working - A grayscale image is expected to be a 2D matrix.

Answer 2

[Aman]

Hi,

As per my understanding, you have an array of grayscale images, and you want to show all of them in a single plot.

The 'Gray' variable has a size of 35*1080*1920, which means it has an image of length 35, width 1080, and number of channels 1920; it doesn’t mean 35 grayscale images of size 1080*1920. You can store the grayscale images in the cell array, and then you can use the ‘subplot' method to plot all of them in a single plot. You can look at the below code for reference.

img = imread("dummy.png");
Gray{1} = rgb2gray(img);
Gray{2} = rgb2gray(img);
Gray{3} = rgb2gray(img);
Gray{4} = rgb2gray(img);
subplot(2,2,1);
imshow(Gray{1});
subplot(2,2,2);
imshow(Gray{2});
subplot(2,2,3);
imshow(Gray{3});
subplot(2,2,4);
imshow(Gray{4});

Hope it helps!