将CMSampleBufferRef转换为OpenCV IplImage的最佳/最快方法是什么？

我正在写一个iPhone应用程序，它使用OpenCV进行某种实时图像检测。什么是将CMSampleBufferRef图像从相机（我使用AVFoundation的AVCaptureVideoDataOutputSampleBufferDelegate）转换为OpenCV能够理解的IplImage的最佳方法？转换需要足够快，以便它可以实时运行。将CMSampleBufferRef转换为OpenCV IplImage的最佳/最快方法是什么？

- (void)captureOutput:(AVCaptureOutput *)captureOutput 
    didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer 
    fromConnection:(AVCaptureConnection *)connection 
{ 
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; 

    // Convert CMSampleBufferRef into IplImage 
    IplImage *openCVImage = ???(sampleBuffer); 

    // Do OpenCV computations realtime 
    // ... 

    [pool release]; 
}

在此先感谢。

来源

2011-03-03 cduck

此示例代码是基于苹果的样品管理CMSampleBuffer的指针：

- (IplImage *)createIplImageFromSampleBuffer:(CMSampleBufferRef)sampleBuffer { 
    IplImage *iplimage = 0; 
    if (sampleBuffer) { 
     CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); 
     CVPixelBufferLockBaseAddress(imageBuffer, 0); 

     // get information of the image in the buffer 
     uint8_t *bufferBaseAddress = (uint8_t *)CVPixelBufferGetBaseAddressOfPlane(imageBuffer, 0); 
     size_t bufferWidth = CVPixelBufferGetWidth(imageBuffer); 
     size_t bufferHeight = CVPixelBufferGetHeight(imageBuffer); 

     // create IplImage 
     if (bufferBaseAddress) { 
      iplimage = cvCreateImage(cvSize(bufferWidth, bufferHeight), IPL_DEPTH_8U, 4); 
      iplimage->imageData = (char*)bufferBaseAddress; 
     } 

     // release memory 
     CVPixelBufferUnlockBaseAddress(imageBuffer, 0); 
    } 
    else 
     DLog(@"No sampleBuffer!!"); 

    return iplimage; 
}

你需要创建一个4通道的IplImage因为手机的摄像头缓存为BGRA。

根据我的经验，这种转换速度足够快，可以在实时应用程序中完成，但是当然，任何添加到其中的内容都会花费时间，特别是对于OpenCV。

来源

2011-03-03 12:33:07

这种运作良好，640x480的图像转换时间为0.00020秒正负0.00004我的iPhone 4 – cduck 2011-03-04 04:06:55

@cduck：是的，即使在3GS上，我使用此解决方案实现了30 fps。 – 2011-03-04 08:12:12

“iplimage-> imageData =（char *）bufferBaseAddress;”会导致内存泄漏。它应该是“memcpy（iplimage-> imageData，（char *）bufferBaseAddress，iplimage-> imageSize）;”

如此完整的编码是：

-(IplImage *)createIplImageFromSampleBuffer:(CMSampleBufferRef)sampleBuffer { 
    IplImage *iplimage = 0; 

    if (sampleBuffer) { 
    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); 
    CVPixelBufferLockBaseAddress(imageBuffer, 0); 

    // get information of the image in the buffer 
    uint8_t *bufferBaseAddress = (uint8_t *)CVPixelBufferGetBaseAddressOfPlane(imageBuffer, 0); 
    size_t bufferWidth = CVPixelBufferGetWidth(imageBuffer); 
    size_t bufferHeight = CVPixelBufferGetHeight(imageBuffer); 

    // create IplImage 
    if (bufferBaseAddress) { 
     iplimage = cvCreateImage(cvSize(bufferWidth, bufferHeight), IPL_DEPTH_8U, 4); 

     //iplimage->imageData = (char*)bufferBaseAddress; 
     memcpy(iplimage->imageData, (char*)bufferBaseAddress, iplimage->imageSize); 
    } 

    // release memory 
    CVPixelBufferUnlockBaseAddress(imageBuffer, 0); 
} 
else 
    DLog(@"No sampleBuffer!!"); 

return iplimage;

}

来源

2012-05-28 03:12:48 ziguli

将CMSampleBufferRef转换为OpenCV IplImage的最佳/最快方法是什么？

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