Assertion error in OpenCV.norm

Question

I'm looking for the difference two image in video with the help of hamming distance. Here is my code:

#include <iostream>
#include "opencv2/opencv.hpp"
using namespace cv; 
int main(int argc, char** argv)
{
    char const* filename = ("video.mp4");
    VideoCapture video(filename);
    Mat frame, temp;
    for(unsigned int i = 0; i<100; i++)
    {
        video >> frame;
        if (i > 0)
        {
            double dist = norm(frame, temp, NORM_HAMMING);
            cout<<"Dist= "<< dist <<endl;
        }
        temp = frame;
    }
    return 0; 
 }

The problem is that in

double dist = norm(frame, temp, NORM_HAMMING);

program falls to

**OpenCV Error**: Assertion failed (normType == NORM_INF || normType == NORM_L1 || normType == NORM_L2 || normType == NORM_L2SQR || ((normType == NORM_HAMMING || normType == NORM_HAMMING2) && src1.type() == CV_8U))in norm, in file /home/andrio/.local/share/Trash/files/build/OpenCV/modules/core/src/stat.cpp, line 3123 terminate called after throwing an instance of 'cv::Exception' what():  /home/andre/.local/share/Trash/files/build/OpenCV/modules/core/src/stat.cpp:3123: error: (-215) normType == NORM_INF || normType == NORM_L1 || normType == NORM_L2 || normType == NORM_L2SQR || ((normType == NORM_HAMMING || normType == NORM_HAMMING2) && src1.type() == CV_8U) in function norm

UPD: This code is work:

double dist = norm(frame, temp, NORM_L2);

Answer 1

You need to bring the image to gray

cvtColor(frame, frame, CV_BGR2GRAY);