OpenCV the mean value of the ROI region RGB, to find the variance, the ROI region color is clearly differentiated

#include <iostream>
#include <math.h>

#include <opencv2/opencv.hpp>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#define REC_W_H 30
using namespace Std;
int main ()
{

Iplimage *res, *DST;
Iplimage *dst1, *dst2, *dst3;
Cvrect rect;
Cvrect rect1, Rect2, rect3;
Rect.x = Rect.y =, Rect.width = rec_w_h, rect.height = rec_w_h;//roi0 coordinates and size
rect1.x = Rect1.y = +, Rect1.width = rec_w_h, rect1.height = rec_w_h;//roi1 coordinates and size
rect2.x = 1230, rect2.y = 510, Rect2.width = rec_w_h, rect2.height = rec_w_h;//roi2 coordinates and size
rect3.x = 1230, RECT3.Y = 560, Rect3.width = rec_w_h, rect3.height = rec_w_h;//roi3 coordinates and size
res = Cvloadimage ("d:/project/tt/1.bmp");//Load a picture
DST = Cvcreateimage (Cvsize (Rec_w_h, Rec_w_h), 8, 3);//Create Image Space
Dst1 = Cvcreateimage (Cvsize (Rec_w_h, Rec_w_h), 8, 3);//Create Image Space 1
Dst2 = Cvcreateimage (Cvsize (Rec_w_h, Rec_w_h), 8, 3);//Create Image Space 2
Dst3 = Cvcreateimage (Cvsize (Rec_w_h, Rec_w_h), 8, 3);//Create Image Space 3
Create window
Cvnamedwindow ("res", cv_window_autosize);
Cvnamedwindow ("DST", cv_window_autosize);
Cvnamedwindow ("Dst1", cv_window_autosize);
Cvnamedwindow ("Dst2", cv_window_autosize);
Cvnamedwindow ("Dst3", cv_window_autosize);

Set ROI Area
Cvsetimageroi (res, rect);
Extract ROI
Cvcopy (res, DST);


Cvsetimageroi (res, rect1);
Cvcopy (res, dst1);


Cvsetimageroi (res, RECT2);
Cvcopy (res, DST2);


Cvsetimageroi (res, RECT3);
Cvcopy (res, DST3);

Cancel Settings
Cvresetimageroi (RES);

Display image
Cvshowimage ("res", res);
Cvshowimage ("DST", DST);

Cvshowimage ("Dst1", dst1);
Cvshowimage ("Dst2", dst2);
Cvshowimage ("Dst3", DST3);


To extract the average value of the image ROI region RGB, we found a cvavg function:
Cvscalar cvavg (const cvarr* arr, const cvarr* mask=null);
Cvscalar avgchannels = Cvavg (DST);
Double AVGB = avgchannels.val[0];
Double Avgg = avgchannels.val[1];
Double AVGR = mean value of Avgchannels.val[2];//roi

Cvscalar avgChannels1 = Cvavg (Dst1);
Double avgB1 = avgchannels1.val[0];
Double avgG1 = avgchannels1.val[1];
Double avgR1 = mean value of Avgchannels1.val[2];//roi 1

Cvscalar avgChannels2 = Cvavg (DST2);
Double avgB2 = avgchannels2.val[0];
Double avgG2 = avgchannels2.val[1];
Double avgR2 = mean value of Avgchannels2.val[2];//roi 2

Cvscalar AVGCHANNELS3 = Cvavg (DST3);
Double avgB3 = avgchannels3.val[0];
Double avgG3 = avgchannels3.val[1];
Double avgR3 = mean value of Avgchannels3.val[2];//roi 3


DOUBLE ret = sqrt (Pow ((AVGB-AVGB2), 2) + POW ((AVGG-AVGG2), 2) + POW ((AVGR-AVGR2), 2));
Double ret1 = sqrt (Pow ((AVGB1-AVGB2), 2) + POW ((AVGG1-AVGG2), 2) + POW ((AVGR1-AVGR2), 2));
Double Ret2 = sqrt (Pow ((AVGB-AVGB3), 2) + POW ((AVGG-AVGG3), 2) + POW ((AVGR-AVGR3), 2));
Double ret3 = sqrt (Pow ((AVGB1-AVGB3), 2) + POW ((AVGG1-AVGG3), 2) + POW ((AVGR1-AVGR3), 2));

cout << "Result:" << ret << Endl;
cout << "RESULT1:" << ret1 << Endl;
cout << "RESULT2:" << ret2 << Endl;
cout << "RESULT3:" << ret3 << endl;//console Print Variance value

CV_BGR2HSV ();

Cvwaitkey (0);

Cvdestroywindow ("res");
Cvdestroywindow ("DST");

Cvdestroywindow ("Dst1");
Cvdestroywindow ("Dst2");
Cvdestroywindow ("Dst3");

Cvreleaseimage (&res);
Cvreleaseimage (&AMP;DST);

Cvreleaseimage (&AMP;DST1);
Cvreleaseimage (&AMP;DST2);
Cvreleaseimage (&AMP;DST3);

return 0;

}

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