MATLAB: Grayscale, monochrome, binary image in matlab

digital image processingimage processingmonochrome

In Matlab,

1. An 8-bit gray scale image has pixel values ranging from 0 to 255. The pixel depth may vary (16-bit, 32-bit, etc)

2. A binary image has pixel values, either 0 or 1 (logical) My question is that, is monochrome image, a binary image or a gray scale image as per points 1 and 2. I need clarification because I want to be 100 % sure about monochrome image.

(As per 'Digital Image Processing Using Matlab' by Gonzalez, Woods, Eddins, a monochrome image is a grayscale image. (Topic 3.2, pg no. 66))

Comments, suggestions are welcome.

Best Answer

A monochrome image is an image with only one colour channel. Thus, both greyscale and binary images are monochrome. Note that the pixel intensities don't necessarily have to be represented in grey, you could just as well use different shades of red.

Related Solutions

MATLAB: Color array to grayscale, images

% Read the image
img1 = imread('photo1.jpg');
% Convert it to double
img1Double = im2double(img1);
% Convert from RGB to grayscale
img1Gray = rgb2gray(img1);
% Display the results
figure
imshowpair(img1, img1Gray, 'montage')

You can do the same for 'photo2.jpg'

MATLAB: How to code image types

Try this:

grayImage = imread(fullFileName);
% Get the dimensions of the image.
% numberOfColorChannels should be = 1 for a gray scale image, and 3 for an RGB color image.
[rows, columns, numberOfColorChannels] = size(grayImage);
if numberOfColorChannels > 1
	% It's not really gray scale like we expected - it's color.
	% Use weighted sum of ALL channels to create a gray scale image.
% 	grayImage = rgb2gray(grayImage);
	% ALTERNATE METHOD: Convert it to gray scale by taking only the green channel,
	% which in a typical snapshot will be the least noisy channel.
	grayImage = grayImage(:, :, 1); % Take red channel.
end
if max(grayImage(:)) == 1 && length(unique(grayImage(:))) == 2
    % It's binary because it has only two values: 0 and 1
else
    % It's grayscale
end

You can also use isa(grayImage, 'logical') or similar to identify what class it is.

Best Answer

Related Solutions

MATLAB: Color array to grayscale, images

MATLAB: How to code image types

Related Question