How to solve this error?

I use R2013a. When I run this code it shows some errors. The code is:

 % read two images
Im1 = imread('a.jpg');
Im2 = imread('b.jpg');

 %  convert images to type double (range from from 0 to 1 instead of from 0 to 255)
Im1 = im2double(Im1);
Im2 = im2double(Im2);

 % Calculate the Normalized Histogram of Image 1 and Image 2
hn1 = imhist(Im1)./numel(Im1);
hn2 = imhist(Im2)./numel(Im2);

 % Calculate the histogram error
f = sum((hn1 - hn2).^2);
f %display the result to console

The error is:

 Error using imhist
Expected input number 1, I or X, to be
two-dimensional.

 Error in imhist>parse_inputs (line 277)
validateattributes(a,
{'double','uint8','int8','logical','uint16','int16','single','uint32',
'int32'}, ...

 Error in imhist (line 59)
[a, n, isScaled, top, map] =
parse_inputs(varargin{:});

 Error in similar (line 10)
hn1 = imhist(Im1)./numel(Im1);

Can anyone please help me to solve this?

Answer 1

[Dishant Arora]

Your image must be a RGB image, See what it says:

ndims(Im1)

imhist only excepts grayscale and indexed image not 3d images

[Prasad Kalane]

Check weather following commands run separately or not... >> I = imread('a.jpg'); >> imhist(I)

If not then convert it to gray

Answer 2

[Saira]

How to solve this error?

Error using imwrite

(line 420)

Expected DATA to be one of these types: numeric, logical. Instead its type was vision.CascadeObjectDetector.

Error in Trainingcode (line 38)

imwrite(Mouth,strcat('E:\SVM\JAFFE Local Features\', int2str(i),int2str(j), '.tiff'));

[Saira]

My Code is working well on MATLAB 2015a but when I run it on MATLAB 2017a, I got this error.

[Sakshi Singh]

convert your input into logical value.