how compute the pixel sum for image?

Hello freinds, I am a beginner in matlab and i want know how compute the pixel sum for image

[Adam]

What is wrong with

doc sum

?! Even as a beginner it is surely the most obvious place to look.

You do need to collapse the image to 1d though or use a double sum, e.g.

pixelSum = sum( myImage(:) );

[houssem rouine]

thank you so much for your helping.

Answer 1

[Pawel Jastrzebski]

1. Use imread - output to load the image into Matlab and store it as a matrix - it can be anything between 2d and 4D matrix
2. Dimension 1 and 2 of the matrix are width and height of the image in pixels

% load the image into the matrix
A = imread('http://www.matlabtips.com/wp-content/uploads/2014/07/64848_wl_cc_logo_membrane_2002_wl.gif');
dims = size(A)
NoOfPixels = prod(dims)
% Note if 'dims' is bigger than 2 elements then:
% NoOfPixels = prod(dims(1:2))

[Fhynthiazien Bobby]

Hi, i tried using the code and my output is as below:

dims =

531 614 3

NoOfPixels =

978102

Therefore sir, does the value 978102 represents the overall sum of pixel for the image??

[Walter Roberson]

No, in that code, NoOfPixels is the number of array elements in the image. It is not necessarily the number of pixels: the number of pixels would be dims(1)*dims(2) . The difference comes about for RGB, in which there are 3 array elements per pixel.

If you are looking for the sum of the pixels, you need to define what that means for RGB.

sum(A, [1 2])    %since R2019a