What is the meaning of if (ndims(a)==2 | (a(:,:,1)==a(:,:,2) & a(:,:,2)==a(:,:,3))) this line?

My code is

clc

clear all

close all

dirpath = 'E:\4-1\image-thesis\implementation\shaila\';

f=dir(fullfile(dirpath,'*.jpg'));

f = f(arrayfun(@(x) x.name(1), f) ~= '.');

for i=1:length(f)

    a=imread(strcat(dirpath,f(i).name));

    if (ndims(a)==2 | (a(:,:,1)==a(:,:,2) &  a(:,:,2)==a(:,:,3)))

    %if (ndims(a)==2)

        figure;imshow(a)

    end

end

What is the meaning of if (ndims(a)==2 | (a(:,:,1)==a(:,:,2) & a(:,:,2)==a(:,:,3))) this line?

[Matt Kindig]

The 'if' statement has the following logic:

1. If the number of dimensions of the image is 2, then imshow() the image.

2. If the number of dimensions is not 2, but all three "planes" of the image (i.e., the values in the third dimension) are all the same, imshow() it.

Basically, this code is reading images (with imread()), and, if a) the image is an indexed image, or b) the image is an RGB image with R, G, and B all the same (which occurs for a grayscale image), then display it using imshow(). Otherwise, skip it.