打開cv不捕獲視頻，直到設置斷點

Question

我使用OpenCV 2.4.7，在Windows服務器2012和VS2012（更新3），提取從opencv-2.4.7.2.exe和以下opencv教程添加所需的路徑到Windows和Visual Studio。 以下代碼在編譯後無效（返回-5），但是當我在 frame = cvQueryFrame(capture);程序中設置斷點時有效。在此行之前和之後使用cvWaitKey(33);，也什麼都不做。

我使用a4tech攝像頭，用一些沒有問題的攝像頭軟件進行測試。我也沒有任何第三方的dll像tbb。

在Visual Studio輸出窗口

，我得到這個行：

'test1.exe' (Win32): Loaded 'C:\Windows\System32\ntdll.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\kernel32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\KernelBase.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'L:\Projects\opencv\opencv\build\x64\vc11\bin\opencv_core247d.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'L:\Projects\opencv\opencv\build\x64\vc11\bin\opencv_imgproc247d.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'L:\Projects\opencv\opencv\build\x64\vc11\bin\opencv_highgui247d.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\msvcp110d.dll'. Symbols loaded. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\msvcr110d.dll'. Symbols loaded. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\user32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\gdi32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\ole32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\oleaut32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\advapi32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\WinSxS\amd64_microsoft.windows.common-controls_6595b64144ccf1df_5.82.9200.16658_none_776622cb3175a40c\comctl32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\msvfw32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\avifil32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\avicap32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\combase.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\msvcrt.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\rpcrt4.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\sechost.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\winmm.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\shell32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\msacm32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\version.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\winmmbase.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\shlwapi.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\imm32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\msctf.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\cryptbase.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\bcryptprimitives.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\uxtheme.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\clbcatq.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\devenum.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\setupapi.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\cfgmgr32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\devobj.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\ntmarta.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\wintrust.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\crypt32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\msasn1.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\msdmo.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\qcap.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\quartz.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\dwmapi.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\ksproxy.ax'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\ksuser.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\d3d9.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\vidcap.ax'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\Kswdmcap.ax'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\mfc42.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\odbc32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\qedit.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\comdlg32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\WinSxS \amd64_microsoft.windows.gdiplus_6595b64144ccf1df_1.1.9200.16518_none_726fbfe0cc22f012\GdiPlus.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\SHCore.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\ddraw.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\dciman32.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\igdumd64.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Unloaded 'C:\Windows\System32\igdumd64.dll' 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\igdumd64.dll'. Cannot find or open the PDB file. 
'test1.exe' (Win32): Unloaded 'C:\Windows\System32\igdumd64.dll' 
'test1.exe' (Win32): Loaded 'C:\Windows\System32\msyuv.dll'. Cannot find or open the PDB file. 

The thread 0x1efc has exited with code -5 (0xfffffffb). 
The thread 0x1540 has exited with code -5 (0xfffffffb). 
The thread 0x1160 has exited with code -5 (0xfffffffb). 
The thread 0x1af8 has exited with code -5 (0xfffffffb). 
The thread 0x1c84 has exited with code -5 (0xfffffffb). 

什麼是這個代碼的問題？或我的配置？

#include "stdafx.h" 

#include <cv.h> 
#include <highgui.h> 

IplImage* imgTracking; 
int lastX = -1; 
int lastY = -1; 

//This function threshold the HSV image and create a binary image 
IplImage* GetThresholdedImage(IplImage* imgHSV){  
    IplImage* imgThresh=cvCreateImage(cvGetSize(imgHSV),IPL_DEPTH_8U, 1); 
cvInRangeS(imgHSV, cvScalar(160,160,60), cvScalar(180,256,256), imgThresh); 
return imgThresh; 
} 

void trackObject(IplImage* imgThresh){ 
// Calculate the moments of 'imgThresh' 
CvMoments *moments = (CvMoments*)malloc(sizeof(CvMoments)); 
cvMoments(imgThresh, moments, 1); 
double moment10 = cvGetSpatialMoment(moments, 1, 0); 
double moment01 = cvGetSpatialMoment(moments, 0, 1); 
double area = cvGetCentralMoment(moments, 0, 0); 

if(area>1000){ 
    // calculate the position of the ball 
    int posX = moment10/area; 
    int posY = moment01/area;   

    if(lastX>=0 && lastY>=0 && posX>=0 && posY>=0) { 
     // Draw a line from the previous point to the current point 
     cvLine(imgTracking, cvPoint(posX, posY), cvPoint(lastX, lastY), cvScalar(0,0,255), 4); 
    } 
    lastX = posX; 
    lastY = posY; 
} 

free(moments); 
} 


int main(){ 

CvCapture* capture =0;  
//....1....cvWaitKey(500); this does nothing 
capture = cvCaptureFromCAM(0); 
//Following line also tested, and nothing happened 
//cvSetCaptureProperty(capture, CV_CAP_PROP_FRAME_WIDTH, 640); 
//cvSetCaptureProperty(capture, CV_CAP_PROP_FRAME_HEIGHT, 480); 
if(!capture){ 
     printf("Capture failure\n"); 
     return -10; 
} 

IplImage* frame=0; 
//....2....cvWaitKey(33); 33 ms delay, does nothing at all 
frame = cvQueryFrame(capture); 
//....3....cvWaitKey(33); 33 ms delay, does nothing at all 
if(!frame) return -5; 

//create a blank image and assigned to 'imgTracking' which has the same size of original video 
imgTracking=cvCreateImage(cvGetSize(frame),IPL_DEPTH_8U, 3); 
//covert the image, 'imgTracking' to black 
cvZero(imgTracking); 

cvNamedWindow("Video");  
cvNamedWindow("Ball"); 

//iterate through each frames of the video  
while(true){ 

    frame = cvQueryFrame(capture);   
    if(!frame) break; 
    frame=cvCloneImage(frame); 

    //smooth the original image using Gaussian kernel 
    cvSmooth(frame, frame, CV_GAUSSIAN,3,3); 

    IplImage* imgHSV = cvCreateImage(cvGetSize(frame), IPL_DEPTH_8U, 3); 
    //Change the color format from BGR to HSV 
    cvCvtColor(frame, imgHSV, CV_BGR2HSV); 
    IplImage* imgThresh = GetThresholdedImage(imgHSV); 

    //smooth the binary image using Gaussian kernel 
    cvSmooth(imgThresh, imgThresh, CV_GAUSSIAN,3,3); 

    //track the possition of the ball 
    trackObject(imgThresh); 

    // Add the tracking image and the frame 
    cvAdd(frame, imgTracking, frame); 

    cvShowImage("Ball", imgThresh);   
    cvShowImage("Video", frame); 

    //Clean up used images 
    cvReleaseImage(&imgHSV); 
    cvReleaseImage(&imgThresh);    
    cvReleaseImage(&frame); 

    //Wait 10mS 
    int c = cvWaitKey(33); 
    //If 'ESC' is pressed, break the loop 
    if((char)c==27) break;  
} 

cvDestroyAllWindows() ; 
cvReleaseImage(&imgTracking); 
cvReleaseCapture(&capture);  

return 0; 
} 

Answer 1

//....2....cvWaitKey(33); 33 ms delay, does nothing at all 

這是預期的行爲，因爲它會等待33毫秒，如果有一個開放的窗口。如果你想要這些線路工作，你應該在該線路之前打開一個窗口。

並嘗試兩次運行線frame = cvQueryFrame(capture);，出於某種原因，它可能無法捕捉圖像，只是嘗試它。