what is the meaning of 28x28x3 in .mat file

Hi, I save a colour image in .mat file format and realise that the variable is in array 28x28x3. 28x28 is image dimension, but I have no idea on what the "3" meant. I guess it is related to colour. Can anyone explain on this ?

here is the code that I type

• pic1 = imread('image_0001.jpg');
• save('BothPics.mat', 'pic1');

Answer 1

[Image Analyst]

That means that there are three slices/color channels/pages/planes/(whatever you want to call them) in your 3D array (stack of 2D images).

Try this:

[rows, columns, numberOfColorChannels] = size(pic1)