VNImageRequestHandler

VNImageRequestHandler.swift

let visionQueue = DispatchQueue(label: "com.viseo.ARML.visionqueue")

private func startDetection() {
    // To avoid force unwrap in VNImageRequestHandler
    guard let buffer = currentBuffer else { return }

    // Right orientation because the pixel data for image captured by an iOS device is encoded in the camera sensor's native landscape orientation
    let requestHandler = VNImageRequestHandler(cvPixelBuffer: buffer, orientation: .right)

    // We perform our CoreML Requests asynchronously.
    visionQueue.async {
        // Run our CoreML Request
        try? requestHandler.perform([self.predictionRequest])

        guard let observation = self.predictionRequest.results?.first as? VNPixelBufferObservation else {
            fatalError("Unexpected result type from VNCoreMLRequest")
        }

        // The resulting image (mask) is available as observation.pixelBuffer

        // Release currentBuffer when finished to allow processing next frame
        self.currentBuffer = nil
    }
}