《OpenCV2 计算机视觉编程手册》视频处理一

本文主要是介绍《OpenCV2 计算机视觉编程手册》视频处理一，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

本文主要结合《OpenCV2 计算机视觉编程手册》第10章的内容，学习OpenCV 处理视频图像的一般方法，包括读入，处理，写出。

1.头文件

#ifndef HEAD_H_
#define HEAD_H_#include <iostream>
#include <iomanip>// 控制输出格式
#include <sstream>// 文件流控制
#include <string>
#include <vector>#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>#endif // HEAD_H_

2. VideoProcessor头文件

#ifndef VPROCESSOR_H_
#define VPROCESSOR_H_#include "head.h"void canny(cv::Mat& img, cv::Mat& out)
{cv::cvtColor(img, out, CV_BGR2GRAY);                      // 灰度转换cv::Canny(out, out, 100, 200);                            // Canny边缘检测cv::threshold(out, out, 128, 255, cv::THRESH_BINARY_INV); // 二值图像反转, 小于128设置为255, 否则为0;即边缘为黑色
}// 抽象类FrameProcessor中纯虚函数process必须在子类(其继承类)中重新定义。
// http://blog.csdn.net/hackbuteer1/article/details/7558868 
// 帧处理器接口
class FrameProcessor 
{public:// 处理方法,定义为纯虚函数, 让其子类实现具体的接口virtual void process(cv:: Mat &input, cv:: Mat &output)= 0;
};class VideoProcessor 
{private:cv::VideoCapture capture;           // OpenCV视频采集对象(object)void (*process)(cv::Mat&, cv::Mat&);// 每帧处理的回调函数, 函数指针调用FrameProcessor *frameProcessor;     // 基类(含纯虚函数的抽象类)FrameProcessor接口指针, 指向子类的实现bool callIt;                        // 启动回调函数与否的bool判断, true:调用, false:不调用std::string windowNameInput;        // 输入显示窗口名字std::string windowNameOutput;       // 输出显示窗口名字int delay;                          // 帧间处理延迟long fnumber;                       // 已处理帧总数long frameToStop;                   // 在该帧停止	  bool stop;                          // 停止处理标志位!std::vector<std::string> images;               // 输入的图像集或者图像向量(vector容器)std::vector<std::string>::const_iterator itImg;// 图像集的迭代器cv::VideoWriter writer;             // OpenCV视频写出对象std::string outputFile;             // 输出视频文件名字int currentIndex;                   // 输出图像集的当前索引int digits;                         // 输出图像文件名字的数字 std::string extension;              // 输出图像集的扩展名// Getting the next frame which could be: video file; camera; vector of imagesbool readNextFrame(cv::Mat& frame) {if (images.size()==0)return capture.read(frame);else {if (itImg != images.end()) {frame= cv::imread(*itImg);itImg++;return frame.data != 0;}else{return false;}}}// Writing the output frame which could be: video file or imagesvoid writeNextFrame(cv::Mat& frame) {if (extension.length()) { // 输出图像文件std::stringstream ss;ss << outputFile << std::setfill('0') << std::setw(digits) << currentIndex++ << extension;cv::imwrite(ss.str(),frame);} else { // 输出视频文件writer.write(frame);}}public:// 构造函数VideoProcessor() : callIt(false), delay(-1), fnumber(0), stop(false), digits(0), frameToStop(-1), process(0), frameProcessor(0) {}// 设置视频文件的名字bool setInput(std::string filename) {fnumber= 0;// In case a resource was already // associated with the VideoCapture instancecapture.release();            // 释放之前打开过的资源images.clear();               // 释放之前打开过的资源return capture.open(filename);// 打开视频文件}// 设置相机IDbool setInput(int id) {fnumber= 0;// In case a resource was already // associated with the VideoCapture instancecapture.release();images.clear();// 打开视频文件return capture.open(id);}// 设置输入的图像集bool setInput(const std::vector<std::string>& imgs) {fnumber= 0;// In case a resource was already // associated with the VideoCapture instancecapture.release();//释放之前打开过的资源// 输入的是图像集images= imgs;itImg= images.begin();return true;}// 设置输出视频文件, 默认参数和输入的一样bool setOutput(const std::string &filename, int codec=0, double framerate=0.0, bool isColor=true) {outputFile= filename;extension.clear();if (framerate==0.0) framerate= getFrameRate(); // 与输入相同char c[4];                     // 使用和输入相同的编码格式if (codec==0) { codec= getCodec(c);}// 打开输出视频return writer.open(outputFile, // 文件名codec,                     // 使用的解码格式 framerate,                 // 帧率getFrameSize(),            // 帧大小isColor);                  // 是否为彩色视频}// 设置输出是图像集, 后缀必须是".jpg", ".bmp" ...bool setOutput(const std::string &filename, // 文件名前缀const std::string &ext,                 // 图像文件后缀 int numberOfDigits=3,                   // 数字位数int startIndex=0)                       // 开始索引000{     if (numberOfDigits<0)                   // 数字位数必须是正数return false;outputFile = filename;                  // 文件名extension  = ext;                       // 公共后缀名digits       = numberOfDigits;          // 文件名中的数字位数 currentIndex = startIndex;              // 开始索引return true;}// 设置每一帧的回调函数void setFrameProcessor(void (*frameProcessingCallback)(cv::Mat&, cv::Mat&)) {// invalidate frame processor class instance 使FrameProcessor实例无效化frameProcessor = 0;process = frameProcessingCallback;callProcess();}// 设置FrameProcessor接口实例void setFrameProcessor(FrameProcessor* frameProcessorPtr) {// invalidate callback function 使回调函数无效化process = 0;frameProcessor= frameProcessorPtr;callProcess();}// 在frame帧停止void stopAtFrameNo(long frame) {frameToStop= frame;}// 处理回调函数void callProcess() {callIt= true;}// 不调用回调函数void dontCallProcess() {callIt= false;}// 显示输入的图像帧void displayInput(std::string wn) {windowNameInput= wn;cv::namedWindow(windowNameInput);}// 显示处理的图像帧void displayOutput(std::string wn) {windowNameOutput= wn;cv::namedWindow(windowNameOutput);}// 不显示处理的图像帧void dontDisplay() {cv::destroyWindow(windowNameInput);cv::destroyWindow(windowNameOutput);windowNameInput.clear();windowNameOutput.clear();}// 设置帧间延迟时间// 0 means wait at each frame// negative means no delayvoid setDelay(int d) {delay= d;}// 处理帧的总数long getNumberOfProcessedFrames() {return fnumber;}// 返回视频帧的大小cv::Size getFrameSize() {if (images.size()==0) {// get size of from the capture deviceint w= static_cast<int>(capture.get(CV_CAP_PROP_FRAME_WIDTH));int h= static_cast<int>(capture.get(CV_CAP_PROP_FRAME_HEIGHT));return cv::Size(w,h);} else { // if input is vector of imagescv::Mat tmp= cv::imread(images[0]);if (!tmp.data) return cv::Size(0,0);else return tmp.size();}}// 返回下一帧的帧数long getFrameNumber() {if (images.size()==0) {// get info of from the capture devicelong f= static_cast<long>(capture.get(CV_CAP_PROP_POS_FRAMES));return f; } else { // if input is vector of imagesreturn static_cast<long>(itImg-images.begin());}}// return the position in msdouble getPositionMS() {// undefined for vector of imagesif (images.size()!=0) return 0.0;double t= capture.get(CV_CAP_PROP_POS_MSEC);return t; }// 返回帧率double getFrameRate() {// undefined for vector of imagesif (images.size()!=0) return 0;double r= capture.get(CV_CAP_PROP_FPS);return r; }// 返回视频中图像的总数long getTotalFrameCount(){// for vector of imagesif (images.size()!=0) return images.size();long t= capture.get(CV_CAP_PROP_FRAME_COUNT);return t; }// 获取输入视频的编解码器int getCodec(char codec[4]) {// 未制定的图像集if (images.size()!=0) return -1;union {// 4-char编码的数据结果int value;char code[4]; } returned;// 获取编码returned.value= static_cast<int>(capture.get(CV_CAP_PROP_FOURCC));// 获得4字符codec[0]= returned.code[0];codec[1]= returned.code[1];codec[2]= returned.code[2];codec[3]= returned.code[3];// 返回对应的整数return returned.value;}// 设置帧位置bool setFrameNumber(long pos) {// for vector of imagesif (images.size()!=0) {// move to position in vectoritImg= images.begin() + pos;// is it a valid position?if (pos < images.size())return true;elsereturn false;} else { // if input is a capture devicereturn capture.set(CV_CAP_PROP_POS_FRAMES, pos);}}// go to this positionbool setPositionMS(double pos) {// not defined in vector of imagesif (images.size()!=0) return false;else return capture.set(CV_CAP_PROP_POS_MSEC, pos);}// go to this position expressed in fraction of total film lengthbool setRelativePosition(double pos) {// for vector of imagesif (images.size()!=0) {// move to position in vectorlong posI= static_cast<long>(pos*images.size()+0.5);itImg= images.begin() + posI;// is it a valid position?if (posI < images.size())return true;elsereturn false;} else { // if input is a capture devicereturn capture.set(CV_CAP_PROP_POS_AVI_RATIO, pos);}}// 停止运行void stopIt() {stop= true;}// 是否已停止运行?bool isStopped() {return stop;}// 判断是否是视频捕获设备或图像集bool isOpened() {return capture.isOpened() || !images.empty();}// 获取并处理图像void run() {cv::Mat frame;  // 当前帧cv::Mat output; // 输出帧// if no capture device has been setif (!isOpened())return;stop= false;while (!isStopped()) {// 读取下一帧if (!readNextFrame(frame))break;// 显示输出帧if (windowNameInput.length()!=0) cv::imshow(windowNameInput,frame);// 调用帧处理回调函数或FrameProcessor实例if (callIt) {  // 处理当前帧if (process)             // 如果是回调函数process(frame, output);else if (frameProcessor) //如果是FrameProcessor实例frameProcessor->process(frame,output);// 增加帧数fnumber++;}else{output= frame;}// 写出输出图像序列if (outputFile.length()!=0)writeNextFrame(output);// 显示输出帧if (windowNameOutput.length()!=0) cv::imshow(windowNameOutput,output);// 引入帧间延迟if (delay>=0 && cv::waitKey(delay)>=0)stopIt();// 检查是否需要停止运行if (frameToStop>=0 && getFrameNumber()==frameToStop)stopIt();}}
};#endif // VPROCESSOR_H_

3. 主函数

#include "head.h"
#include "videoprocessor.h"int main()
{//----Zero Test----cv::VideoCapture capture("../bike.avi"); // 打开视频/摄像头0if (!capture.isOpened())return 1;double rate= capture.get(CV_CAP_PROP_FPS);// 获取帧率bool stop(false);cv::Mat frame;                            // 当前帧cv::namedWindow("Extracted Frame");int delay= 1000/rate;                     // 延迟的毫秒//int delay = 1000;// 处理视频所有帧while (!stop) {// read next frame if anyif (!capture.read(frame))break;cv::imshow("Extracted Frame",frame);if (cv::waitKey(delay)>=0)            // 延迟等待直到cv::waitKey(delay)<0stop= true;}capture.release();                       // 因为capture自动调用析构函数，所以capture.release不是必须的!cv::waitKey();//----First Test----VideoProcessor processor;                           // 创建VideoProcessor类实例 processorprocessor.setInput("../bike.avi");                  // 打开视频文件bike.aviprocessor.displayInput("Input Video");              // 声明输入视频显示窗口processor.displayOutput("Output Video");            // 声明输出视频显示窗口processor.setDelay(1000./processor.getFrameRate()); // 设置播放视频为原始输入视频帧率processor.setFrameProcessor(canny);                 // 设置帧处理器的回调函数--cannyprocessor.run();                                    // 开始处理视频文件cv::waitKey();                                      // 等待按键响应//----Second test----processor.setInput("../bike.avi");                            // 重新设置打开视频cv::Size size= processor.getFrameSize();                      // 获取视频文件的基本信息std::cout << size.width << " " << size.height << std::endl;   // 视频图像的宽度(列)和高度(行)std::cout << processor.getFrameRate() << std::endl;           // 视频的帧率std::cout << processor.getTotalFrameCount() << std::endl;     // 视频总的帧数std::cout << processor.getFrameNumber() << std::endl;         // 视频帧的编号std::cout << processor.getPositionMS() << std::endl;          // 视频帧的位置(ms)processor.dontCallProcess();                                   // 不处理打开视频文件// 输出.jpg视频图像到output文件夹, 图像名字为bikeOut000.jpg~bikeOut118.jpgprocessor.setOutput("../output/bikeOut",".jpg");               processor.run(); cv::waitKey();// 输出bike.avi视频到output文件夹,编解码器为:XVID, 基于MPEG-4视频标准的开源解码库char codec[4];                                                 // 编解码器标识processor.setOutput("../output/bike.avi",processor.getCodec(codec),processor.getFrameRate());std::cout << "Codec: " << codec[0] << codec[1] << codec[2] << codec[3] << std::endl;processor.run();cv::waitKey();//----Three test----processor.setInput("../bike.avi");processor.displayInput("Input Video");              // 声明输入视频显示窗口processor.displayOutput("Output Video");            // 声明输出视频显示窗口processor.setFrameNumber(80);                       // 设置帧的位置processor.stopAtFrameNo(120);                       // 停止的帧位置processor.setDelay(1000./processor.getFrameRate());processor.run();cv::waitKey();return 0;
}

Canny边缘检测