四月的筆記

曝光設定參考在OpenCV官網內的set有關主要參數有兩個

CAP_PROP_AUTO_EXPOSURE 開啟要不要打開

CAP_PROP_EXPOSURE 設定曝光值

CAP_PROP_AUTO_EXPOSURE
CAP_PROP_EXPOSURE

https://docs.opencv.org/4.x/d4/d15/group__videoio__flags__base.html

int auto_mode = 3;
int manual_mode = 1;
int exposure_number = 5;

cap.set(cv::CAP_PROP_AUTO_EXPOSURE, auto_mode);   //  自動模式
cap.set(cv::CAP_PROP_AUTO_EXPOSURE, manual_mode); //  關閉自動模式
cap.set(cv::CAP_PROP_EXPOSURE, exposure_number);  //  設定曝光值

void Auto_Exposure_OnOff(VideoCapture& cap, bool TurnOn = true, int exposure_number = 0)
{
    int auto_mode = 3;
    int manual_mode = 1;

    cap.set(cv::CAP_PROP_AUTO_EXPOSURE, auto_mode);

    if (!TurnOn)
    {
        cap.set(cv::CAP_PROP_AUTO_EXPOSURE, manual_mode);
        cap.set(cv::CAP_PROP_EXPOSURE, exposure_number);
    }


}

 

示範程序:

// g++ opencv-camera.cpp -o a.out `pkg-config --cflags --libs opencv`
#include <opencv2/opencv.hpp>
using namespace std;
using namespace cv;



bool Check_VideoCapture_isOpened(const VideoCapture& cap, bool falseMessage_Ouput = true, string fail_Message = "Cannot open camera \n")
{
    bool check0 = cap.isOpened();
    if (falseMessage_Ouput && !check0)
        cout << fail_Message;
    return check0;
}


bool Check_VideoCapture_read(VideoCapture& cap, Mat& frame, bool falseMessage_Ouput = true, string fail_Message = "Can't receive frame (stream end?). Exiting ...\n")
{
    bool check0 = cap.read(frame);
    if (falseMessage_Ouput && !check0)
        cout << fail_Message;
    return check0;
}


/////////////////////////////////////////////////////


void Color_Cout(const Mat& frame, int Select_color1)
{
    for (int i = 0; i < frame.rows; i = i + 10)
    {
        for (int j = 0; j < frame.cols * 3; j = j + 3 * 10)
            cout << (int)frame.at<unsigned char>(i, j + Select_color1) << " ";
        cout << endl;
    }
    cout << endl << endl;
}



void Auto_Exposure_OnOff(VideoCapture& cap, bool TurnOn = true, int exposure_number = 0)
{
    int auto_mode = 3;
    int manual_mode = 1;

    cap.set(cv::CAP_PROP_AUTO_EXPOSURE, auto_mode);

    if (!TurnOn)
    {
        cap.set(cv::CAP_PROP_AUTO_EXPOSURE, manual_mode);
        cap.set(cv::CAP_PROP_EXPOSURE, exposure_number);
    }


}






int main() {

    Mat frame0, frame1;
    VideoCapture cap0(0), cap1(1);
    Check_VideoCapture_isOpened(cap0);
    Auto_Exposure_OnOff(cap0, true);

    Check_VideoCapture_isOpened(cap1);
    Auto_Exposure_OnOff(cap1, false,-5);


    int Camera_Number = 0;
   
    while (true) 
    {
        if (Camera_Number == 0) 
        {
            Check_VideoCapture_read(cap0, frame0);
            imshow("live", frame0);
        }
        else
        {
            Check_VideoCapture_read(cap1, frame1);
            imshow("live", frame1);
        }

        int WK = waitKey(1);
        if (WK == 'q') 
        {
            break;
        }
        else if (WK == 'a')
        {
            if (Camera_Number == 0)
                Camera_Number = 1;
            else 
                Camera_Number = 0;
        }
        else if (WK == 's')
        {
            cout << "Camera Size:" << frame0.total() << endl;
            cout << "Camera rows:" << frame0.rows << endl;
            cout << "Camera cols:" << frame0.cols << endl;
        }
        else if (WK == 'd')
        {
            int R_color1(2), G_color1(1), B_color1(0);
            if (Camera_Number == 0)
            {
                Color_Cout(frame0, R_color1);
                Color_Cout(frame0, G_color1);
                Color_Cout(frame0, B_color1);
            }
            else if (Camera_Number == 1)
            {
                Color_Cout(frame1, R_color1);
                Color_Cout(frame1, G_color1);
                Color_Cout(frame1, B_color1);
            }
        }
    }
    return 0;
}