TensorFlowLite.Tensor到UUImage

Question

我是swift，TFlite和IOS的新手。我成功地转换了，运行了我的模型。然而，最后，我需要重建一个图像。我的TFlite模型返回一个TFLite.tensor Float32 4d形状(1，高，宽，3)。

let outputTensor: Tensor
outputTensor = try myInterpreter.output(at: 0)

我正在寻找一个没有阿尔法的RGB图片。在python中，它将如下所示：

Image.fromarray((np.array(outputTensor.data) * 255).astype(np.uint8))

据我所知，最好的方法是制作一个CVPixelBuffer，应用CoreOS转换(针对x255)，最后制作UUImage。我深深地迷失在IOS文档中，它存在许多可能性，社区有什么建议吗？

++t

Answer 1

在谷歌示例中，可以对UIImage的扩展进行编码：

extension UIImage {
    convenience init?(data: Data, size: CGSize) {
        let width = Int(size.width)
        let height = Int(size.height)

        let floats = data.toArray(type: Float32.self)

        let bufferCapacity = width * height * 4
        let unsafePointer = UnsafeMutablePointer<UInt8>.allocate(capacity: bufferCapacity)
        let unsafeBuffer = UnsafeMutableBufferPointer<UInt8>(
            start: unsafePointer,
            count: bufferCapacity)
        defer {
            unsafePointer.deallocate()
        }

        for x in 0..<width {
            for y in 0..<height {
                let floatIndex = (y * width + x) * 3
                let index = (y * width + x) * 4
                let red = UInt8(floats[floatIndex] * 255)
                let green = UInt8(floats[floatIndex + 1] * 255)
                let blue = UInt8(floats[floatIndex + 2] * 255)

                unsafeBuffer[index] = red
                unsafeBuffer[index + 1] = green
                unsafeBuffer[index + 2] = blue
                unsafeBuffer[index + 3] = 0
            }
        }

        let outData = Data(buffer: unsafeBuffer)

        // Construct image from output tensor data
        let alphaInfo = CGImageAlphaInfo.noneSkipLast
        let bitmapInfo = CGBitmapInfo(rawValue: alphaInfo.rawValue)
            .union(.byteOrder32Big)
        let colorSpace = CGColorSpaceCreateDeviceRGB()
        guard
            let imageDataProvider = CGDataProvider(data: outData as CFData),
            let cgImage = CGImage(
                width: width,
                height: height,
                bitsPerComponent: 8,
                bitsPerPixel: 32,
                bytesPerRow: MemoryLayout<UInt8>.size * 4 * Int(size.width),
                space: colorSpace,
                bitmapInfo: bitmapInfo,
                provider: imageDataProvider,
                decode: nil,
                shouldInterpolate: false,
                intent: .defaultIntent
            )
        else {
            return nil
        }
        self.init(cgImage: cgImage)
    }
}

然后，通过TFLite的推理，可以很容易地构造出图像。

let outputTensor: Tensor
outputTensor = try decoder.output(at: 0)
image = UIImage(data: outputTensor.data, size: size) ?? UIImage()