How to find the variance of an image?

i try to find the variance by var function but it shoew the error. I = imread('eight.tif'); var(I)

Answer 1

[David Young]

var requires a double or single argument. This will work:

img = double(imread('eight.tif'));
v = var(img);

But note that will give a vector, with one value for the variance of each column of the image. To get the variance of all the pixels in the image, you'll need

v = var(img(:));

Answer 2

[Dheeraj Kuamr Gupta]

close all; clear all; clc; I = imread('C:\Users\anubh\Pictures\koala.jpg'); A=rgb2gray(I); [r,c]=size(A) b=r*c; s=0; s=sum(sum(A)); mean=a/b; display(mean); d=(A- mean); display(d);

Answer 3

[Morteza Hajitabar Firuzjaei]

This code calculates the variance of a RGB image but it's not standard variance, see below:

%------------------------------------------

close all;

clear all;

clc;

I = imread('b.png');

blockSize = [6 6];

varFilterFunction = @(theBlockStructure) var(double(theBlockStructure.data(:)));

blockyImagevar = blockproc(I, blockSize, varFilterFunction);

varianceImage=blockyImagevar(:);

display(varianceImage);

%---------------------------------------

Morteza Hajitabar Firuzjaei

Answer 4

[Komal Gaikwad]

how to display the variance of image in command box

[Image Analyst]

Leave off the semicolon, or use disp() or fprintf().