导出16位灰度深度图像（1440x1920）-Swift IOS15.3

Question

我想导出有关iOS的捕获的数据（用于机器学习目的）的16位灰度PNG。 我正在使用带有激光雷达传感器的新iPadpro来捕获Datra。 我已经获得了192x256的深度图，我将其缩放为7.5，以匹配我的RGB图像的1440x1920分辨率。这是我到目前为止的代码：

func convertDepthToImg(frame: ARFrame) {
        let depthBuffer = frame.sceneDepth?.depthMap
        var ciImageDepth:CIImage    = CIImage(cvPixelBuffer: depthBuffer!) 

        // Transform image on pixel level to get the same size as rgb, apply nearest neighbour sampling or linear sampling (depends on performance in network)   
        let transformation          = CGAffineTransform(scaleX: 7.5, y: 7.5) 
            ciImageDepth            = ciImageDepth.samplingLinear()
                                        .transformed(by: combined_transf_matrix)
        let contextDepth:CIContext  = CIContext(options: nil)  
        let cgImageDepth:CGImage    = contextDepth.createCGImage((ciImageDepth), from: ciImageDepth.extent)!

        // convert to required 16 bits gray png img
        convertTo16BitGrayPng(image: cgImageDepth)
    }

    // Function to create vImageBuffer for more functionality on Images
    func createVImg(image: CGImage) -> vImage_Buffer? {
        guard let vImageBuffer = try? vImage_Buffer(cgImage: image)
        else {
            return nil
        }
        return vImageBuffer
    }

    func convertTo16BitGrayPng(image: CGImage){
        let width = 1440
        let height = 1920

        //create vImageBuffer vor UIImage
        var srcBuf = createVImg(image: image)
        print("Height: ", String(srcBuf!.height))
        print("Width: ", String(srcBuf!.width))

        // allocate memory for final size:
        let bv = malloc(width * height * 4)!
        var db = vImage_Buffer(data: bv,
                               height: vImagePixelCount(height),
                               width: vImagePixelCount(width),
                               rowBytes: width*2)

        // create pointer to Buffer that contains the image data
        vImageConvert_PlanarFtoPlanar16F(&(srcBuf)!, &db, vImage_Flags(kvImageNoFlags))
        let bp = bv.assumingMemoryBound(to: UInt16.self)
        let prov = CGDataProvider(data: CFDataCreateWithBytesNoCopy(kCFAllocatorDefault,
                                                                    bp,
                                                                    height * width * 4,
                                                                kCFAllocatorDefault))!
        let cgImage = CGImage(width: width,
                              height: height,
                              bitsPerComponent: 5,  
                              bitsPerPixel: 16,
                              bytesPerRow: 2 * width, 
                              space: CGColorSpace(name: CGColorSpace.linearSRGB)!, 
                              bitmapInfo: CGBitmapInfo(rawValue: CGImageAlphaInfo.noneSkipFirst.rawValue), 
                              provider: prov,
                              decode: nil,
                              shouldInterpolate: false,
                              intent: .defaultIntent)

        // save processed image to documents dir
        saveDptToDocs(cgImage: cgImage!, type: "dpt")
    }

... save Image to documentpath (works fine)

我使用这个问题回答将我的图像转换为16位并将其保存到我的文档目录中，但是我只能获得24位图像。我真的无法获得16位的出口工作。 我已经在32、64、8甚至24位导出了图像。但是，16位有些棘手吗？ 请帮忙。

Answer 1

如果您的输出图像为16位灰度，我认为您初始化的颜色空间cgimage应该是灰度颜色空间（例如cgcolorspacecreatedevicegray（））和> BitsperComponent和bitsperpixel都应16。另外，bitmapinfo应沿着：

CGBitmapInfo.byteOrder16Little.rawValue |
CGBitmapInfo.floatComponents.rawValue |
CGImageAlphaInfo.none.rawValue