ios - 如何将 BGRA 图像保存到 iphone，然后将其带到笔记本电脑进行后期处理

Question

我想用iphone的相机拍一张原始图像数据，然后在笔记本电脑上用matlab或opencv进行后处理。所以我需要把这个原始图像数据从 iphone 带到笔记本电脑上。

目前，我使用 AVFoudnation 获取 32BGRA 图像(它是原始图像数据，对吧？)。我将它保存为文件，但我无法从 iphone 中获取它。 (有没有不越狱的解决方案？)

以下是一些相关代码:

    if let videoConnection = stillImageOutput!.connectionWithMediaType(AVMediaTypeVideo) {
        videoConnection.videoOrientation = AVCaptureVideoOrientation.Portrait
        stillImageOutput?.captureStillImageAsynchronouslyFromConnection(videoConnection, completionHandler: {(sampleBuffer, error) in
            if (sampleBuffer != nil) {                                   
                // get the raw image data
                let cameraFrame = CMSampleBufferGetImageBuffer(sampleBuffer)

                CVPixelBufferLockBaseAddress(cameraFrame!, 0)

                let rawImage = CVPixelBufferGetBaseAddress(cameraFrame!)
                let bytesPerRow = CVPixelBufferGetBytesPerRow(cameraFrame!)
                let rawImageData = NSData.init(bytes: rawImage, length: bytesPerRow*CVPixelBufferGetHeight(cameraFrame!))

                // process the rawImageData, we now save it
                var paths = NSSearchPathForDirectoriesInDomains (.DocumentDirectory, .UserDomainMask, true);
                let documentsDirectory = paths[0]
                let fileName = documentsDirectory.stringByAppendingString("/rawImageData")                    

                do {
                    try rawImageData.writeToFile(fileName, options: NSDataWritingOptions.DataWritingFileProtectionComplete)
                } catch {

                }
                print("Raw image data write successfully.")
                print("Path of raw image data: ", fileName)                   
                CVPixelBufferUnlockBaseAddress(cameraFrame!, 0)               
            }
        })
    }

是否需要将BGRA数据保存到相册中再取出，如果需要，怎么办(用UIImage？)

谢谢。

更新:

我把BGRA图片转成UIImage，用UIImageWriteToSavedPhotosAlbum保存到相册，然后用airdrop把图片文件传到may mac。但是，我发现图像是 JPEG 格式。怎么了？以下是代码:

            if (sampleBuffer != nil) {                   
                let rawImage:UIImage = self.imageFromSampleBuffer(sampleBuffer)
                self.capturedImage.image = rawImage
                UIImageWriteToSavedPhotosAlbum(rawImage, nil, nil, nil)                    
                print("Raw Image write to photo album successfully")  
            }

// Create a UIImage from sample buffer data
func imageFromSampleBuffer(sampleBuffer : CMSampleBufferRef) -> UIImage
{
// Get a CMSampleBuffer's Core Video image buffer for the media data
let  imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
// Lock the base address of the pixel buffer
CVPixelBufferLockBaseAddress(imageBuffer!, 0);


// Get the number of bytes per row for the pixel buffer
let baseAddress = CVPixelBufferGetBaseAddress(imageBuffer!);

// Get the number of bytes per row for the pixel buffer
let bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer!);
// Get the pixel buffer width and height
let width = CVPixelBufferGetWidth(imageBuffer!);
let height = CVPixelBufferGetHeight(imageBuffer!);

// Create a device-dependent RGB color space
let colorSpace = CGColorSpaceCreateDeviceRGB();

// Create a bitmap graphics context with the sample buffer data
var bitmapInfo: UInt32 = CGBitmapInfo.ByteOrder32Big.rawValue
bitmapInfo |= CGImageAlphaInfo.PremultipliedLast.rawValue & CGBitmapInfo.AlphaInfoMask.rawValue
let context = CGBitmapContextCreate(baseAddress, width, height, 8,
bytesPerRow, colorSpace, bitmapInfo);
// Create a Quartz image from the pixel data in the bitmap graphics context
let quartzImage = CGBitmapContextCreateImage(context);
// Unlock the pixel buffer
CVPixelBufferUnlockBaseAddress(imageBuffer!,0);

// Create an image object from the Quartz image
let image = UIImage.init(CGImage: quartzImage!);

return (image);
}

Answer 1

我找到一个解决办法:把BGRA转成UIImage，再转成PNG，然后保存到相册。由于PNG是一种无损压缩图像格式，这意味着我也得到了bmp图像。

                let rawImage:UIImage = self.imageFromSampleBuffer(sampleBuffer)                    
                let img = UIImagePNGRepresentation(rawImage)
                let pngImg = UIImage.init(data: img!)                                       
                self.capturedImage.image = pngImg
                UIImageWriteToSavedPhotosAlbum(pngImg!, nil, nil, nil)                   
                print("PNG Image write to photo album successfully")