当应用程序不再需要时，如何从运行停止 CoreML？

Question

我的应用程序在 CoreML 模型上运行 Vision。运行机器学习模型的相机帧来自 ARKit sceneView（基本上是相机）。我有一个名为 loopCoreMLUpdate() 的方法，它会持续运行 CoreML，以便我们在新相机帧上保持运行模型。代码如下所示：

import UIKit
import SceneKit
import ARKit

class MyViewController: UIViewController {
    var visionRequests = [VNRequest]()
    let dispatchQueueML = DispatchQueue(label: "com.hw.dispatchqueueml") // A Serial Queue

    override func viewDidLoad() {
        super.viewDidLoad()

        // Setup ARKit sceneview
        // ...

        // Begin Loop to Update CoreML
        loopCoreMLUpdate()
    }

    // This is the problematic part. 
    // In fact - once it's run there's no way to stop it, is there?
    func loopCoreMLUpdate() {
        // Continuously run CoreML whenever it's ready. (Preventing 'hiccups' in Frame Rate)

        dispatchQueueML.async {
            // 1. Run Update.
            self.updateCoreML()

            // 2. Loop this function.
            self.loopCoreMLUpdate()
        }   
    }

    func updateCoreML() {
        ///////////////////////////
        // Get Camera Image as RGB
        let pixbuff : CVPixelBuffer? = (sceneView.session.currentFrame?.capturedImage)
        if pixbuff == nil { return }
        let ciImage = CIImage(cvPixelBuffer: pixbuff!)
        // Note: Not entirely sure if the ciImage is being interpreted as RGB, but for now it works with the Inception model.
        // Note2: Also uncertain if the pixelBuffer should be rotated before handing off to Vision (VNImageRequestHandler) - regardless, for now, it still works well with the Inception model.

        ///////////////////////////
        // Prepare CoreML/Vision Request
        let imageRequestHandler = VNImageRequestHandler(ciImage: ciImage, options: [:])
        // let imageRequestHandler = VNImageRequestHandler(cgImage: cgImage!, orientation: myOrientation, options: [:]) // Alternatively; we can convert the above to an RGB CGImage and use that. Also UIInterfaceOrientation can inform orientation values.

        ///////////////////////////
        // Run Image Request
        do {
            try imageRequestHandler.perform(self.visionRequests)
        } catch {
            print(error)
        }

    }

}

如您所见，循环效果是由 DispatchQueue 和标签 com.hw.dispatchqueueml 不断调用 loopCoreMLUpdate() 创建的。一旦不再需要 CoreML，有没有办法停止队列？完整代码是 here.

Answer 1

我建议在 viewDidLoad 中使用运行 coreML 模型，您可以使用 ARSessionDelegate 函数。 func session(_ session: ARSession, didUpdate frame: ARFrame) 方法来获取帧，你可以设置标志，在这里当你想让模型工作和不工作时启用。像下面这样：

func session(_ session: ARSession, didUpdate frame: ARFrame) { // 这是我们分析框架的地方

      // We return early if currentBuffer is not nil or the tracking state of camera is not normal

    // TODO: - Core ML Functionality Commented
      guard isMLFlow else { //
             return
      }
      currentBuffer = frame.capturedImage
      guard let buffer = currentBuffer, let image = UIImage(pixelBuffer: buffer) else { return }
     <Code here to load model>
      CoreMLManager.manager.updateClassifications(for: image)
}

当应用程序不再需要时，如何从运行停止 CoreML？

How to stop CoreML from running when it's no longer needed in the app?

ios

swift

coreml

当应用程序不再需要时，如何从 运行 停止 CoreML？

How to stop CoreML from running when it's no longer needed in the app?

ios

swift

coreml

当应用程序不再需要时，如何从运行停止 CoreML？