heartrate/images/roi_test_code.m

@@ -1,11 +1,3 @@
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-% Region of Interest
-%
-% Author:LY Pechvattana, MINH Meng Hour
-% Date: 19/02/2023
-%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
 I = imread('image1.png');
 imshow(I)
 im = drawrectangle()

heartrate/main.m

@@ -1,11 +1,3 @@
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-% Heart Rate Estimation
-%
-% Author:LY Pechvattana, MINH Meng Hour
-% Date: 19/02/2023
-%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
 %set variable 
 fps = 15;
 windowDuration = 30;
@@ -47,25 +39,36 @@ greenChannel_std = std(greenChannel);
 
 %normalization
 for i = 1:450
-    greenChannel_normal(i) = (greenChannel(i)-greenChannel_avg)/greenChannel_std;
+    greenChannel_normal(i) = (greenChannel(i)-greenChannel_avg);
 end
 
 %Fast Fourier transform (fft) of Green Channel
 greenChannel_fft = fft(greenChannel_normal);
 
 
-%power spectrum
+%power spectrum P1
 L = length(greenChannel_normal);
 P2 = abs(greenChannel_fft/L);
 P1 = P2(1:L/2+1);
 P1(2:end-1)=2*P1(2:end-1);
 f = 15*(0:(L/2))/L;
 
+P1 = fftshift(P1);
+
 plot(f,P1);
 title("Power Spectrum")
 xlabel("frequency (Hz)")
 ylabel("Power Spectrum")
 
+%peak - compute the freq vector
+[m n]=size(P1);
+x = 1:n;
+y= 1:m;
+[X Y]=meshgrid(x, y);
+X = X - floor(n/2)-1;
+Y = Y - floor(m/2)-1;
+f = sqrt(X.^2 + Y.^2);
+
 %peak - find the peak in range
 indices = (f>=0.75)&(f<=4);
 [peaks locations] = findpeaks(P1(indices), 'SortStr','descend');