I want to find PCA of an image... but when i run the code i get following error..
Error using - Integers can only be combined with integers of the same class, or scalar doubles. Error in pca (line 26) data = data - repmat(mn,1,N);
here is the code....'
function [signals,PC,V] = pca()
I = imread('C:\Users\div\Pictures\Picture1.png');
I = rgb2gray( I);
[irow, icol] = size(I);
data = reshape(I',irow*icol,1);
% [sR ,sC ,eR ,eC] = deal(1, 3, 2, 4);
% Compute the sum over the region using the integral image.
% PCA1: Perform PCA using covariance.
% data - MxN matrix of input data
% (M dimensions, N trials)
% signals - MxN matrix of projected data
% PC - each column is a PC
% V - Mx1 matrix of variances
[M,N] = size(data);
% subtract off the mean for each dimension
mn = mean(data,2);
data = data - repmat(mn,1,N);
% calculate the covariance matrix
covariance = 1 / (N-1) * data * data;
% find the eigenvectors and eigenvalues
[PC, V] = eig(covariance);
% extract diagonal of matrix as vector
V = diag(V);
% sort the variances in decreasing order
[junk, rindices] = sort(-1*V);
V = V(rindices); PC = PC(:,rindices);
% project the original data set
signals = PC * data;
