opencv 判断两张图片的相似度 - 程序员大本营 (pianshen.com)
Goal¶
Today it is common to have a digital video recording system at your disposal. Therefore, you will eventually come to the situation that you no longer process a batch of images, but video streams. These may be of two kinds: real-time image feed (in the case of a webcam) or prerecorded and hard disk drive stored files. Luckily OpenCV threats these two in the same manner, with the same C++ class. So here’s what you’ll learn in this tutorial:
- How to open and read video streams
- Two ways for checking image similarity: PSNR and SSIM
The source code
As a test case where to show off these using OpenCV I’ve created a small program that reads in two video files and performs a similarity check between them. This is something you could use to check just how well a new video compressing algorithms works. Let there be a reference (original) video like this small Megamind clip and a compressed version of it. You may also find the source code and these video file in the samples/cpp/tutorial_code/HighGUI/video-input-psnr-ssim/ folder of the OpenCV source library.
#include <iostream> // for standard I/O
#include <string> // for strings
#include <iomanip> // for controlling float print precision
#include <sstream> // string to number conversion
#include <opencv2/core/core.hpp> // Basic OpenCV structures (cv::Mat, Scalar)
#include <opencv2/imgproc/imgproc.hpp> // Gaussian Blur
#include <opencv2/highgui/highgui.hpp> // OpenCV window I/O
using namespace std;
using namespace cv;
double getPSNR ( const Mat& I1, const Mat& I2);
Scalar getMSSIM( const Mat& I1, const Mat& I2);
int main(int argc, char *argv[])
help();
if (argc != 5)
{
cout << "Not enough parameters" << endl;
return -1;
}
stringstream conv;
const string sourceReference = argv[1], sourceCompareWith = argv[2];
int psnrTriggerValue, delay;
conv << argv[3] << endl << argv[4]; // put in the strings
conv >> psnrTriggerValue >> delay; // take out the numbers
char c;
int frameNum = -1; // Frame counter
VideoCapture captRefrnc(sourceReference), captUndTst(sourceCompareWith);
if (!captRefrnc.isOpened())
{
cout << "Could not open reference " << sourceReference << endl;
return -1;
}
if (!captUndTst.isOpened())
{
cout << "Could not open case test " << sourceCompareWith << endl;
return -1;
}
Size refS = Size((int) captRefrnc.get(CV_CAP_PROP_FRAME_WIDTH),
(int) captRefrnc.get(CV_CAP_PROP_FRAME_HEIGHT)),
uTSi = Size((int) captUndTst.get(CV_CAP_PROP_FRAME_WIDTH),
(int) captUndTst.get(CV_CAP_PROP_FRAME_HEIGHT));
if (refS != uTSi)
{
cout << "Inputs have different size!!! Closing." << endl;
return -1