QT和OpenCV 显示视频 http://zllxsha.blog.163.com/blog/static/50555091201011892029213/

【存档】QT和OpenCV 显示视频 （存着） 

2010-12-08 21:20:29|  分类：默认分类 |  标签：|字号大中小订阅

Qt开发的程序一般都要借助qmake生成makefile文件。因此为了加入opencv库就要修改.pro文件，下面是Linux下该文件的配置。(增加的部分)

INCLUDEPATH+= . /usr/local/include/opencv
LIBS+= /usr/local/lib/libcv.so \
       /usr/local/lib/libcvaux.so \
       /usr/local/lib/libcxcore.so \
       /usr/local/lib/libhighgui.so \
       /usr/local/lib/libml.so

Opencv中通过摄像头捕捉到的每帧图像的数据结构是IplImage类型的，要把它显示到Qt窗口中就需要把它转化为QImage类型的图像。

#include<QVector>
#include<cstring>

QImage MyThread::IplImageToQImage(const IplImage* iplImage,double mini,double maxi)
...{
    uchar*qImageBuffer= NULL;

       int width = iplImage->width;

/**//* Note here that OpenCV image is stored so that each lined is
32-bits aligned thus
* explaining the necessity to "skip" the few last bytes of each
line of OpenCV image buffer.
*/
       int widthStep= iplImage->widthStep;
       int height = iplImage->height;

       switch (iplImage->depth)
       ...{
           case IPL_DEPTH_8U:
           if(iplImage->nChannels== 1)
           ...{
           /**//* OpenCV image is stored with one byte grey pixel. We convert it
            to an 8 bit depth QImage.
           */
  
                qImageBuffer= (uchar *) malloc(width*height*sizeof(uchar));
                uchar*QImagePtr = qImageBuffer;
               const uchar *iplImagePtr = (const uchar*) iplImage->imageData;
  
               for(int y= 0; y< height; y++)
               ...{
                   // Copy line by line
                        memcpy(QImagePtr, iplImagePtr, width);
                        QImagePtr+= width;
                        iplImagePtr+= widthStep;
                }
  
            }
           else if(iplImage->nChannels== 3)
           ...{
                   /**//* OpenCV image is stored with 3 byte color pixels (3 channels).
                    We convert it to a 32 bit depth QImage.
                   */
                    qImageBuffer= (uchar *) malloc(width*height*4*sizeof(uchar));
                    uchar*QImagePtr = qImageBuffer;
                   const uchar *iplImagePtr = (const uchar*) iplImage->imageData;
                   for(int y= 0; y< height; y++)
                   ...{
                       for (int x= 0; x< width; x++)
                       ...{
                               // We cannot help but copy manually.
                                QImagePtr[0]= iplImagePtr[0];
                                QImagePtr[1]= iplImagePtr[1];
                                QImagePtr[2]= iplImagePtr[2];
                                QImagePtr[3]= 0;
      
                                QImagePtr+= 4;
                                iplImagePtr+= 3;
                        }
                        iplImagePtr+= widthStep-3*width;
                    }   
  
            }
           else
           ...{
                    qDebug("IplImageToQImage: image format is not supported : depth=8U and %d channels ", iplImage->nChannels);
            }
           break;
           case IPL_DEPTH_16U:
           if(iplImage->nChannels== 1)
           ...{
           /**//* OpenCV image is stored with 2 bytes grey pixel. We convert it
            to an 8 bit depth QImage.
           */
                    qImageBuffer= (uchar *) malloc(width*height*sizeof(uchar));
                    uchar*QImagePtr = qImageBuffer;
                   //const uint16_t *iplImagePtr = (const uint16_t *);
           const unsignedint *iplImagePtr= (const unsignedint *)iplImage->imageData;
                   for (int y= 0; y< height; y++)
                   ...{
                       for (int x= 0; x< width; x++)
                       ...{
                       // We take only the highest part of the 16 bit value. It is
                       //similar to dividing by 256.
                           *QImagePtr++= ((*iplImagePtr++)>> 8);
                        }
                        iplImagePtr+= widthStep/sizeof(unsignedint)-width;
                    }
            }
           else
           ...{
                    qDebug("IplImageToQImage: image format is not supported : depth=16U and %d channels ", iplImage->nChannels);
  
            }
           break;
           case IPL_DEPTH_32F:
            if(iplImage->nChannels== 1)
            ...{
           /**//* OpenCV image is stored with float (4 bytes) grey pixel. We
            convert it to an 8 bit depth QImage.
           */
                     qImageBuffer= (uchar *) malloc(width*height*sizeof(uchar));
                     uchar*QImagePtr = qImageBuffer;
                    const float *iplImagePtr= (constfloat *) iplImage->imageData;
                    for(int y= 0; y< height; y++)
                    ...{
                        for(int x= 0; x< width; x++)
                        ...{
                                 uchar p;
                                float pf = 255* ((*iplImagePtr++)- mini) / (maxi - mini);
                                if(pf < 0) p= 0;
                                else if(pf> 255) p= 255;
                                else p = (uchar) pf;
  
                                *QImagePtr++= p;
                          }
                         iplImagePtr+= widthStep/sizeof(float)-width;
                     }
             }
            else
            ...{
                     qDebug("IplImageToQImage: image format is not supported : depth=32F and %d channels ", iplImage->nChannels);
             }   
              break;
              case IPL_DEPTH_64F:
            if(iplImage->nChannels== 1)
            ...{
               /**//* OpenCV image is stored with double (8 bytes) grey pixel. We
                convert it to an 8 bit depth QImage.
               */
                    qImageBuffer= (uchar *) malloc(width*height*sizeof(uchar));
                    uchar*QImagePtr = qImageBuffer;
                   const double *iplImagePtr= (constdouble *) iplImage->imageData;
                   for(int y= 0; y< height; y++)
                   ...{
                       for(int x= 0; x< width; x++)
                       ...{
                                uchar p;
                               double pf = 255* ((*iplImagePtr++)- mini) / (maxi - mini);
  
                               if(pf < 0) p= 0;
                               else if(pf> 255) p= 255;
                               else p = (uchar) pf;
  
                               *QImagePtr++= p;
                        }
                        iplImagePtr+= widthStep/sizeof(double)-width;
                    }
            }
           else
           ...{
                    qDebug("IplImageToQImage: image format is not supported : depth=64F and %d channels ", iplImage->nChannels);
            }
           break;
           default:
                qDebug("IplImageToQImage: image format is not supported : depth=%d and %d channels ", iplImage->depth, iplImage->nChannels);
        }

        QImage qImage;
        QVector<QRgb> vcolorTable;
       if(iplImage->nChannels== 1)
       ...{
           // We should check who is going to destroy this allocation.
            QRgb*colorTable= new QRgb[256];
           for(int i= 0; i< 256; i++)
           ...{
                   colorTable[i]= qRgb(i, i, i);
                   vcolorTable[i]= colorTable[i];
            }
            qImage= QImage(qImageBuffer, width, height, QImage::Format_Indexed8).copy();
            qImage.setColorTable(vcolorTable);
        }
       else
       ...{
            qImage= QImage(qImageBuffer, width, height, QImage::Format_RGB32).copy();
        }
    free(qImageBuffer);
   return qImage;
}

于是你可以下面的代码(部分)测试一下：摄像头获取每一帧IplImage*类型的图像，转化为QImage类型的图像，用update()发出一个paintEvent(QPaintEvent*)事件，如此不断更新图像。(IplImageToQImage中的mini和maxi默认初始化为0)

void ImageViewer::paintEvent(QPaintEvent *)...{
    QPainter painter(this);
    painter.drawImage(QPoint(0,0),*image);
}

bool ImageViewer::ShowImage()...{
    IplImage*pImage = NULL;
    CvCapture*pCapture = NULL;
   if((pCapture = cvCaptureFromCAM(-1))== NULL)...{
        cout<< "Open camera failed!";
       return false;
    }
   while((pImage= cvQueryFrame(pCapture))!= NULL)...{
        image= IplImageToQImage(pImage);
        update();
    }
    cvReleaseImage(&pImage);
    cvReleaseCapture(&pCapture);
   return true;
}

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