// 简单实现

 cv::namedWindow("Example 2-3", cv::WINDOW_AUTOSIZE);

    cv::VideoCapture cap;

    cap.open(0);

    cout << "Opened file: " << argv[1] << endl;

    cv::Mat frame, frame_threshold;

    int low_r = 30, low_g = 30, low_b = 30;

    int high_r = 100, high_g = 100, high_b = 100;

    for (;;) {

        cap >> frame;

        if (frame.empty()) break; // Ran out of film

        inRange(frame, cv::Scalar(low_b, low_g, low_r), cv::Scalar(high_b, high_g, high_r), frame_threshold);

        //-- Show the frames

        imshow("Video Capture", frame);

        imshow("Object Detection", frame_threshold);

        if ((char)cv::waitKey(33) >= 0) break;

    }

    return 0;

// 完整实现

#include "opencv2/imgproc.hpp"

#include "opencv2/highgui.hpp"

#include <iostream>

#include <stdlib.h>

using namespace std;

using namespace cv;

void on_low_r_thresh_trackbar(int, void*);

void on_high_r_thresh_trackbar(int, void*);

void on_low_g_thresh_trackbar(int, void*);

void on_high_g_thresh_trackbar(int, void*);

void on_low_b_thresh_trackbar(int, void*);

void on_high_b_thresh_trackbar(int, void*);

int low_r = 30, low_g = 30, low_b = 30;

int high_r = 100, high_g = 100, high_b = 100;

int main()

{

    Mat frame, frame_threshold;

    VideoCapture cap(0);

    namedWindow("Video Capture", WINDOW_NORMAL);

    namedWindow("Object Detection", WINDOW_NORMAL);

    //-- Trackbars to set thresholds for RGB values

    createTrackbar("Low R", "Object Detection", &low_r, 255, on_low_r_thresh_trackbar);

    createTrackbar("High R", "Object Detection", &high_r, 255, on_high_r_thresh_trackbar);

    createTrackbar("Low G", "Object Detection", &low_g, 255, on_low_g_thresh_trackbar);

    createTrackbar("High G", "Object Detection", &high_g, 255, on_high_g_thresh_trackbar);

    createTrackbar("Low B", "Object Detection", &low_b, 255, on_low_b_thresh_trackbar);

    createTrackbar("High B", "Object Detection", &high_b, 255, on_high_b_thresh_trackbar);

    while ((char)waitKey(1) != 'q') {

        cap >> frame;

        if (frame.empty())

            break;

        //-- Detect the object based on RGB Range Values

        inRange(frame, Scalar(low_b, low_g, low_r), Scalar(high_b, high_g, high_r), frame_threshold);

        //-- Show the frames

        imshow("Video Capture", frame);

        imshow("Object Detection", frame_threshold);

    }

    return 0;

}

void on_low_r_thresh_trackbar(int, void*)

{

    low_r = min(high_r - 1, low_r);

    setTrackbarPos("Low R", "Object Detection", low_r);

}

void on_high_r_thresh_trackbar(int, void*)

{

    high_r = max(high_r, low_r + 1);

    setTrackbarPos("High R", "Object Detection", high_r);

}

void on_low_g_thresh_trackbar(int, void*)

{

    low_g = min(high_g - 1, low_g);

    setTrackbarPos("Low G", "Object Detection", low_g);

}

void on_high_g_thresh_trackbar(int, void*)

{

    high_g = max(high_g, low_g + 1);

    setTrackbarPos("High G", "Object Detection", high_g);

}

void on_low_b_thresh_trackbar(int, void*)

{

    low_b = min(high_b - 1, low_b);

    setTrackbarPos("Low B", "Object Detection", low_b);

}

void on_high_b_thresh_trackbar(int, void*)

{

    high_b = max(high_b, low_b + 1);

    setTrackbarPos("High B", "Object Detection", high_b);

}