Swift: Convert Grayscale Image to CVPixelBuffer containing disparity - swift

Question

I have a gray scale image of depth data that has been upsampled from its original resolution. I'm stuck as to how I can convert the pixel values of the upscaled depth image (r,g,b) to a float.
Is there a way to convert the level of whiteness of a pixel a float value?
Is there anyway I could convert the CVPixelBufferFormatTypes of the CVPixelBuffer associated with the image?
Said another way, is there a way to convert the pixel buffer of a gray scale image into CVpixelbuffer containing disparity floats?
I use the following code to extract the cvpixelbuffer from a cgimage representation of the upsampled depth data:-
func pixelBuffer() -> CVPixelBuffer? {
let frameSize = CGSize(width: self.width, height: self.height)
//COLOR IS BGRA
var pixelBuffer:CVPixelBuffer? = nil
let status = CVPixelBufferCreate(kCFAllocatorDefault, Int(frameSize.width), Int(frameSize.height), kCVPixelFormatType_32BGRA , nil, &pixelBuffer)
if status != kCVReturnSuccess {
return nil
}
CVPixelBufferLockBaseAddress(pixelBuffer!, CVPixelBufferLockFlags.init(rawValue: 0))
let data = CVPixelBufferGetBaseAddress(pixelBuffer!)
let rgbColorSpace = CGColorSpaceCreateDeviceRGB()
let bitmapInfo = CGBitmapInfo(rawValue: CGBitmapInfo.byteOrder32Big.rawValue | CGImageAlphaInfo.premultipliedFirst.rawValue)
let context = CGContext(data: data, width: Int(frameSize.width), height: Int(frameSize.height), bitsPerComponent: 8, bytesPerRow: CVPixelBufferGetBytesPerRow(pixelBuffer!), space: rgbColorSpace, bitmapInfo: bitmapInfo.rawValue)
context?.draw(self, in: CGRect(x: 0, y: 0, width: self.width, height: self.height))
CVPixelBufferUnlockBaseAddress(pixelBuffer!, CVPixelBufferLockFlags(rawValue: 0))
return pixelBuffer
}