Basler Pylon 和 OpenCV，为什么图像窗口是空白的？ [复制]

Question

我是 C++ 的初学者，但我已经使用 Python 使用 OpenCV 进行了一些 blob 检测。但是使用 C++，我什至无法将相机流传送到窗口。

相机为Basler DAA3840-45UC，平台为Win10。

谁能帮我解释为什么“imshow("Smaller", resized_down);"显示空白窗口但“Pylon::DisplayImage(1, ptrGrabResult);”正在显示相机视图？

编辑：我没有在“imshow”之后添加“waitKey”。现在可以了。

PylonInitialize();
    
    try
    {
    CBaslerUniversalInstantCamera camera(CTlFactory::GetInstance().CreateFirstDevice());

    camera.MaxNumBuffer = 5;

    camera.StartGrabbing(GrabStrategy_LatestImageOnly);

    CGrabResultPtr ptrGrabResult;

    while (camera.IsGrabbing()) {
        CImageFormatConverter fc;
        fc.OutputPixelFormat = PixelType_BGR8packed;

        camera.RetrieveResult(5000, ptrGrabResult, TimeoutHandling_ThrowException);

        CImageFormatConverter converter;

        CPylonImage image;

        int scale_percent = 25;
     
        if (ptrGrabResult->GrabSucceeded())
        {
            fc.Convert(image, ptrGrabResult);

            Mat cv_img = cv::Mat(ptrGrabResult->GetHeight(), ptrGrabResult->GetWidth(), CV_8UC3, (uint8_t*)image.GetBuffer());
            
            cv::Size sz = cv_img.size();
            int imageWidth = sz.width;
            int imageHeight = sz.height;
            int down_width = imageWidth * scale_percent / 100;
            int down_height = imageHeight * scale_percent / 100;
            Mat resized_down;
            resize(cv_img, resized_down, Size(down_width, down_height), INTER_LINEAR);
            imshow("Smaller", resized_down);  
            
#ifdef PYLON_WIN_BUILD
            Pylon::DisplayImage(1, ptrGrabResult); 
            
#endif

Answer 1

以下代码可帮助您作为使用 Opencv 运行 Pylon 相机 的指南。如果您可以分享您要使用的相机类型和平台，我可能会为您提供更多帮助。请相应地编辑您的问题。

注意：即使您似乎发现了问题，您共享的代码中也应该缺少行，这就是为什么我想将这个答案分享给看到这篇与问题。

#include <iostream>
#include <opencv2/opencv.hpp>
#include <pylon/PylonIncludes.h>
#include <pylon/usb/BaslerUsbInstantCamera.h>
#include <pylon/gige/BaslerGigEInstantCamera.h>

using namespace Pylon;
using namespace GenApi;
using namespace Basler_UsbCameraParams;

int main()
{
     Pylon::PylonAutoInitTerm autoInitTerm;
    CImageFormatConverter formatConverter;
    CPylonImage pylonImage;
    CGrabResultPtr ptrGrabResult;
    CBaslerUsbInstantCamera *pylon_camera;
    //CBaslerGigEInstantCamera *pyloncamera2;
    cv::Mat frame,playingFrame,cannyFrame,contoursFrame;
    cv::namedWindow("Input",0);
    //cv::namedWindow("Output",0);


    cv::RNG rng(12345);



    pylon_camera = new CBaslerUsbInstantCamera(CTlFactory::GetInstance().CreateFirstDevice());


    pylon_camera->MaxNumBuffer = 1;
    formatConverter.OutputPixelFormat= PixelType_Mono8;
    pylon_camera->StartGrabbing();
    pylon_camera->AcquisitionFrameRate=60.0;







    while (1) {
        if(pylon_camera->IsGrabbing())
        {

            pylon_camera->RetrieveResult(5000, ptrGrabResult, TimeoutHandling_ThrowException);

            if(ptrGrabResult->GrabSucceeded() && pylon_camera->IsGrabbing())
            {

                pylon_camera->ExposureAuto.SetValue(ExposureAuto_Off);
                pylon_camera->ExposureTime.SetValue(20000);

                pylon_camera->BslBrightness.SetValue(0.0);
                pylon_camera->BslContrast.SetValue(0.0);




                const uint8_t *pImageBuffer = (uint8_t *) ptrGrabResult->GetBuffer();
                formatConverter.Convert(pylonImage, ptrGrabResult);
                frame = cv::Mat(ptrGrabResult->GetHeight(), ptrGrabResult->GetWidth(), CV_8UC1, (uint8_t *) pylonImage.GetBuffer());




                cv::imshow("Input",frame);

                int c = cv::waitKey(1);
                if((char)c == 'c')
                    break;

            }

        }
    }


    pylon_camera->Close();
    pylon_camera->StopGrabbing();



    return 0;
}