OpenCV Mat与UIImage之间的转换

　　UIImage 转 OpenCV cvMat：

 - (cv::Mat)cvMatWithImage:(UIImage *)image
 {
     CGColorSpaceRef colorSpace = CGImageGetColorSpace(image.CGImage);
     CGFloat cols = image.size.width;
     CGFloat rows = image.size.height;

     cv::Mat cvMat(rows, cols, CV_8UC4); // 8 bits per component, 4 channels

     CGContextRef contextRef = CGBitmapContextCreate(cvMat.data,                 // Pointer to backing data
                                                     cols,                       // Width of bitmap
                                                     rows,                       // Height of bitmap
                                                     ,                          // Bits per component
                                                     cvMat.step[],              // Bytes per row
                                                     colorSpace,                 // Colorspace
                                                     kCGImageAlphaNoneSkipLast |
                                                     kCGBitmapByteOrderDefault); // Bitmap info flags

     CGContextDrawImage(contextRef, CGRectMake(, , cols, rows), image.CGImage);
     CGContextRelease(contextRef);

     return cvMat;
 }

　　OpenCV cvMat 转 UIImage ：　

 - (UIImage *)UIImageFromCVMat:(cv::Mat)cvMat {
     NSData *data = [NSData dataWithBytes:cvMat.data length:cvMat.elemSize()*cvMat.total()];

     CGColorSpaceRef colorSpace;
     CGBitmapInfo bitmapInfo;

     if (cvMat.elemSize() == ) {
         colorSpace = CGColorSpaceCreateDeviceGray();
         bitmapInfo = kCGImageAlphaNone | kCGBitmapByteOrderDefault;
     } else {
         colorSpace = CGColorSpaceCreateDeviceRGB();
         bitmapInfo = kCGBitmapByteOrder32Little | (
                                                    cvMat.elemSize() == ? kCGImageAlphaNone : kCGImageAlphaNoneSkipFirst
                                                    );
     }

     CGDataProviderRef provider = CGDataProviderCreateWithCFData((__bridge CFDataRef)data);

     // Creating CGImage from cv::Mat
     CGImageRef imageRef = CGImageCreate(
                                         cvMat.cols,                 //width
                                         cvMat.rows,                 //height
                                         ,                          //bits per component
                                          * cvMat.elemSize(),       //bits per pixel
                                         cvMat.step[],              //bytesPerRow
                                         colorSpace,                 //colorspace
                                         bitmapInfo,                 // bitmap info
                                         provider,                   //CGDataProviderRef
                                         NULL,                       //decode
                                         false,                      //should interpolate
                                         kCGRenderingIntentDefault   //intent
                                         );

     // Getting UIImage from CGImage
     UIImage *finalImage = [UIImage imageWithCGImage:imageRef];
     CGImageRelease(imageRef);
     CGDataProviderRelease(provider);
     CGColorSpaceRelease(colorSpace);

     return finalImage;
 }