最近在練習使用OpenCV，順手紀錄一些用法。下面這段code可以用來控制電腦上的webcam進行拍照並且轉換成QImage物件，以便後續的使用。
```c++ webcam.cpp
#include
CvCapture *camera; IplImage *frame;
camera = cvCreateCameraCapture(-1);
/* We need to call cvRetrieveFrame twice here to get the last frame. * TODO: figure out the root cause and use correct method instead of * the workaround. / cvGrabFrame(camera); frame = cvRetrieveFrame(camera); frame = cvRetrieveFrame(camera); if (frame) { QImage image(reinterpret_cast(frame->imageData), frame->width, frame->height, frame->widthStep, QImage::Format_RGB888); QImage colorCorrectedImage(image.rgbSwapped()); / Show colorCorrectedImage which contains the picture. */ … } cvReleaseCapture(&camera);
```