Error using rgb2gray>parse_inputs , MAP must be a m x 3 array. Use im2gray for RGB and grayscale images.

Hi!

I am trying to do skeletonization and segmentation on binarized image. However, when I used the binarized image for this functions. It gives me an error. Please see an attachment for reference.

I shall be thankful for your suggestions!

Best

Omer

Answer 1

[Walter Roberson]

Example:

IMG = imread('cameraman.tif');
size(IMG)

ans = 1×2

256 256

gr = rgb2gray(IMG);

Error using rgb2gray>parse_inputs (line 79)
MAP must be a m x 3 array. Use im2gray for RGB and grayscale images.

Error in rgb2gray (line 51)
isRGB = parse_inputs(X);

In other words, what you are passing to rgb2gray() is not an RGB image.

If you want to save a step in testing whether an input is already grayscale or not, you can substitute im2gray() for rgb2gray(): im2gray() will return arrays unchanged if they are already grayscale.

Note: binarized images are usually datatype logical() and already 2D. If you had a particular reason to convert them to grayscale then use im2double() or im2uint8()

[Omer Iqbal]

Thanks for your response!

Now , I am getting a new error after I gave the RGB image. Please see an attachment and codes below;

Select multiple Ridges files (they must be in a single folder)

Select multiple Ridges files (they must be in a single folder)

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

This is image 1 out of 1

Performing Otsu Thresholding Segmentation for Image 1 out of 1

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Error using imadjust>parseInputs (line 215)

Specified syntax IMADJUST(I) is only supported for 2-D grayscale images. Additional input arguments are required for use

with RGB images.

Error in imadjust (line 105)

parseInputs(varargin{:});

Error in Ridge_Post_Processing (line 90)

imageIN_3 = imadjust(imageIN_2);

215 error(message('images:imadjust:oneArgOnlyGrayscale','IMADJUST(I)'))

K>>