OpenCV4入门159：基于颜色的对象跟踪

索引地址：系列索引

本文实现跟踪指定颜色，其实就是将指定颜色的目标明显的表示出来。既然是跟踪那么肯定是动态的目标。

我的移动硬盘是蓝色，本文就来跟踪它。

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#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"

#include <iostream>

using namespace cv;
using namespace std;

int main(int argc, char* argv[])
{
    // Create the capture object
    // 0 -> input arg that specifies it should take the input from the webcam
    VideoCapture cap(0);

    if(!cap.isOpened())
    {
        cerr << "Unable to open the webcam. Exiting!" << endl;
        return -1;
    }

    Mat frame, hsvImage, mask, outputImage;
    char ch;

    // Image size scaling factor for the input frames from the webcam
    float scalingFactor = 0.75;

    // Iterate until the user presses the Esc key
    while(true)
    {
        // Initialize the output image before each iteration
        outputImage = Scalar(0,0,0);

        // Capture the current frame
        cap >> frame;

        // Check if 'frame' is empty
        if(frame.empty())
            break;

        // Resize the frame
        resize(frame, frame, Size(), scalingFactor, scalingFactor, INTER_AREA);

        // Convert to HSV colorspace
        cvtColor(frame, hsvImage, COLOR_BGR2HSV);

        // Define the range of "blue" color in HSV colorspace
        Scalar lowerLimit = Scalar(60,100,100);
        Scalar upperLimit = Scalar(180,255,255);

        // Threshold the HSV image to get only blue color
        inRange(hsvImage, lowerLimit, upperLimit, mask);

        // Compute bitwise-AND of input image and mask
        bitwise_and(frame, frame, outputImage, mask=mask);

        // Run median filter on the output to smoothen it
        medianBlur(outputImage, outputImage, 5);

        // Display the input and output image
        imshow("Input", frame);
        imshow("Output", outputImage);

        // Get the keyboard input and check if it's 'Esc'
        // 30 -> wait for 30 ms
        // 27 -> ASCII value of 'ESC' key
        ch = waitKey(30);
        if (ch == 27) {
            break;
        }
    }

    return 0;
}

效果为：

colortracker