corrMatching2.m

function [x y maxVal] = corrMatching2(frameImg, templateImg, opt)
% -------------------------------------------------------------------------
% Function corrMatching: Template Matching using Correlation Coefficients
% Inputs: 
%           frameImg = gray or color frame image
%           templateImg = gray or color template image
%           threshC = threshold of rejecting detected region (default = .75)
%                     e.g. if the detected region has a corrCoef>threshC
%                     then the algorithm accepts it as a detection,
%                     otherwise rejects it as a false alarm.
% Output: 
%           corrScore = 2D matrix of correlation coefficients
%           boundingBox = [upperLeftPixel.y upperLeftPixel.x height width]
%
% -------------------------------------------------------------------------
% By Yue Wu (Rex)
% Department of Electrical and Computer Engineering
% Tufts University
% Medford, MA
% 08/30/2010
% -------------------------------------------------------------------------

%% 1. initialization

if size(frameImg,3) ~=1
    frameGray = rgb2gray(frameImg);
else
    frameGray = frameImg;
end
frameGray = double(frameGray);

if size(templateImg,3) ~=1
    templateGray = rgb2gray(templateImg);
else
    templateGray = templateImg;
end

templateGray = double(templateGray);
[templateHeight,templateWidth] = size(templateGray);


%% 2. correlation calculation

frameMean = fftolamopt2(frameGray,ones(size(templateGray))./numel(templateGray),opt);
templateMean = mean(templateGray(:));

corrPartI = fftolamopt2(frameGray,fliplr(flipud(templateGray-templateMean)),opt)./numel(templateGray);
corrPartII = frameMean.*sum(templateGray(:)-templateMean);
stdFrame = sqrt(fftolamopt2(frameGray.^2,ones(size(templateGray))./numel(templateGray),opt)-frameMean.^2);
stdTemplate = std(templateGray(:));
corrScore = (corrPartI-corrPartII)./(stdFrame.*stdTemplate);
%figure(3);imshow(corrScore); drawnow; 
%% 3. finding most likely region

[maxVal,maxIdx] = max(corrScore(:));
[y, x] = ind2sub([size(corrScore,1),size(corrScore,2)],maxIdx);
%figure(3); hold on; plot(x,y,'rx');
x = x-round(templateWidth/2);
y = y-round(templateHeight/2);