dnn example question.

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Hello,

I want to port that application here https://docs.opencv.org/master/d5/d86... to a server app. I managed to read the model and get the embeddings for the pictures, so far so good.

What i dont get it is the following line:

var personVec = persons[name];
var score = vec.dot(personVec);

For me the dot product is always 1 - even when the embeddings have different values. I guess my math is not good enough here to understand.

#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/dnn.hpp"
#include <math.h>
#include <iostream>
using namespace cv;
using namespace std;
using namespace dnn;

Mat eval( Net net, Mat face) {
    Mat blob = blobFromImage(face, 1.0 / 255, Size(96, 96), Scalar(0,0,0,0), true, false);
    net.setInput(blob);
    Mat result = net.forward();
    return result;
}


int main( int argc, char** argv)
{   
    Net net = readNetFromTorch("openface.nn4.small2.v1.t7");
    net.setPreferableTarget(DNN_TARGET_OPENCL);
    cout << "read model" << endl;

    Mat face1 = imread("face1.jpeg");   
    Mat face1Vec = eval(net, face1);
    cout << "Face1Vec" << face1Vec << endl;

    Mat face2 = imread("face2.jpeg");   
    Mat face2Vec = eval(net, face2);
    cout << "Face2Vec" << face2Vec << endl;

        auto s1 = face1Vec.dot(face1Vec);
        auto s2 = face1Vec.dot(face2Vec);

        cout << "s1: " << s1 << endl;    
        cout << "s2: " << s2 << endl; 
    return 0;
}