如何将ARKit深度数据（CVPixelBuffer）转换为16位灰度PNG图像文件？

Question

根据Apple官方示例，我做了一些尝试。这是我的代码：

CGImage 扩展

//ARSessionDelegate
func session(_ session: ARSession, didUpdate frame: ARFrame) {
    let depthMap = frame.sceneDepth.depthMap
    let ciImage = CIImage(cvPixelBuffer: depthMap)
    let cgImage = CIContext().createCGImage(ciImage, from: ciImage.extent)
    let grayscaleCGImage = cgImage.toGrayscale() //CGImage extension
    let image = UIImage(cgImage: grayscaleCGImage)
    let data = image.pngData()
    
    //Save data to iPhone as "example.png" PNG file...
    //Get "example.png" PNG file from iPhone, copy PNG file to MacOS...
}

然后在 MacOS 终端中，我运行此代码 sips -g all example.png，我从终端获得以下信息：

  pixelWidth: 256
  pixelHeight: 192
  typeIdentifier: public.png
  format: png
  formatOptions: default
  dpiWidth: 72.000
  dpiHeight: 72.000
  samplesPerPixel: 1
  bitsPerSample: 8
  hasAlpha: no
  space: Gray

The bitsPerSample is 8，但我想要它到为16。有人可以帮助我吗？多谢！