openCV（二）---iOS中使用openCV的图片格式转换

可以实现将UIImage和IplImage类型实现相互转换

//由于OpenCV主要针对的是计算机视觉方面的处理，因此在函数库中，最重要的结构体是IplImage结构。

- (IplImage *)CreateIplImageFromUIImage:(UIImage *)image {

// Getting CGImage from UIImage

CGImageRef imageRef = image.CGImage;

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

// Creating temporal IplImage for drawing

IplImage *iplimage = cvCreateImage(

cvSize(image.size.width,image.size.height), IPL_DEPTH_8U, 4

);

// Creating CGContext for temporal IplImage

CGContextRef contextRef = CGBitmapContextCreate(

iplimage->imageData, iplimage->width, iplimage->height,

iplimage->depth, iplimage->widthStep,

colorSpace, kCGImageAlphaPremultipliedLast|kCGBitmapByteOrderDefault

);

// Drawing CGImage to CGContext

CGContextDrawImage(

contextRef,

CGRectMake(0, 0, image.size.width, image.size.height),

imageRef

);

CGContextRelease(contextRef);

CGColorSpaceRelease(colorSpace);

// Creating result IplImage

IplImage *ret = cvCreateImage(cvGetSize(iplimage), IPL_DEPTH_8U, 3);

cvCvtColor(iplimage, ret, CV_RGBA2BGR);

cvReleaseImage(&iplimage);

return ret;

}

- (UIImage *)UIImageFromIplImage:(IplImage *)image {

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

// Allocating the buffer for CGImage

NSData *data =

[NSData dataWithBytes:image->imageData length:image->imageSize];

CGDataProviderRef provider =

CGDataProviderCreateWithCFData((__bridge CFDataRef)data);

// Creating CGImage from chunk of IplImage

CGImageRef imageRef = CGImageCreate(

image->width, image->height,

image->depth, image->depth * image->nChannels, image->widthStep,

colorSpace, kCGImageAlphaNone|kCGBitmapByteOrderDefault,

provider, NULL, false, kCGRenderingIntentDefault

);

// Getting UIImage from CGImage

UIImage *ret = [UIImage imageWithCGImage:imageRef];

CGImageRelease(imageRef);

CGDataProviderRelease(provider);

CGColorSpaceRelease(colorSpace);

return ret;

}

实现CvMat和UIImage的相互转换

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

    if (cvMat.elemSize() == ) {
        colorSpace = CGColorSpaceCreateDeviceGray();
    } else {
        colorSpace = CGColorSpaceCreateDeviceRGB();
    }

    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
                                        kCGImageAlphaNone|kCGBitmapByteOrderDefault,// 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;
}

// UIImage to cvMat
- (cv::Mat)cvMatFromUIImage:(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  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);
    CGColorSpaceRelease(colorSpace);

    return cvMat;
}