我正在尝试让一个简单的矩形跟踪控制器运行,并且我可以很好地进行矩形检测,但是跟踪请求总是以我无法找到的原因而失败。
有时跟踪请求会在失败之前触发它的回调几次,有时它会在单个回调发生之前立即失败。我觉得这与我提交请求的方式有关,但我无法深入了解它。
这是视图控制器的代码
class TestController: UIViewController, AVCaptureVideoDataOutputSampleBufferDelegate {
// Video capture
private var videoSession = AVCaptureSession()
private var videoLayer: AVCaptureVideoPreviewLayer!
// Detection
private var detectionRequest: VNDetectRectanglesRequest?
private let sequenceHandler = VNSequenceRequestHandler()
// Tracking
private var trackingRequest: VNTrackRectangleRequest?
private var shape: Detection?
private var pixelBuffer: CVImageBuffer?
// MARK: Setup
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
startVideoFeed()
}
override func viewDidLayoutSubviews() {
videoLayer.frame = view.layer.bounds
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
startDetectingRectangles()
}
private func startDetectingRectangles() {
let request = VNDetectRectanglesRequest(completionHandler: didDetectRectangle)
request.maximumObservations = 1
request.minimumSize = 0.07
request.minimumConfidence = 0.9
request.minimumAspectRatio = 0.5
request.maximumAspectRatio = 2
request.quadratureTolerance = 10
detectionRequest = request
}
private func didDetectRectangle(request: VNRequest, error: Error?) {
// Fetch results of the correct type
guard let observations = request.results, observations.count > 0 else { return }
let results = observations.map { $0 as? VNRectangleObservation }
for case let rectangle? in results {
detectionRequest = nil
let request = VNTrackRectangleRequest(rectangleObservation: rectangle, completionHandler: didTrackRectangle)
trackingRequest = request
}
}
private func didTrackRectangle(request: VNRequest, error: Error?) {
// Fetch results of the correct type
guard let observation = request.results?.first as? VNRectangleObservation else { return }
// Create or update UI
}
// Start capturing video frames
private func startVideoFeed() {
// Session config
videoSession.sessionPreset = .photo
// Create device and input to device
guard
let captureDevice = AVCaptureDevice.default(for: .video),
let deviceInput = try? AVCaptureDeviceInput(device: captureDevice)
else {
fatalError("Error setting up capture device.")
}
// Setup device output
let deviceOutput = AVCaptureVideoDataOutput()
deviceOutput.setSampleBufferDelegate(self, queue: DispatchQueue.global(qos: .default))
// Set input and output
videoSession.addInput(deviceInput)
videoSession.addOutput(deviceOutput)
// Setup video display layer
videoLayer = AVCaptureVideoPreviewLayer(session: videoSession)
videoLayer.frame = view.bounds
videoLayer.videoGravity = .resizeAspectFill
view.layer.addSublayer(videoLayer)
videoSession.startRunning()
}
func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)
guard let pixelBuffer = pixelBuffer else { return }
do {
var requests: [VNRequest] = []
if let detectionRequest = detectionRequest {
requests.append(detectionRequest) }
if let trackingRequest = trackingRequest {
requests.append(trackingRequest) }
try sequenceHandler.perform(requests, on: pixelBuffer, orientation: .right)
} catch {
print(error)
}
}
}
错误正在打印:
错误域 = com.apple.vis 代码 = 9“内部错误:跟踪其中一个角失败,置信度 = 0.000000;阈值 = 0.650000” UserInfo={NSLocalizedDescription=内部错误:跟踪其中一个角失败,置信度 = 0.000000 ; 阈值 = 0.650000}
这是在跟踪请求第一次失败后的每一帧输出的,并且请求永远不会自行恢复。这try sequenceHandler.perform(requests, on: pixelBuffer, orientation: .right)
是引发错误的行(然后我打印)。
我查看了散布在网络上的对象观察示例,它们似乎需要在每一帧都发出新的跟踪请求来跟踪对象。我试过VNTrackRectangleRequest
在didTrackRectangle
函数中创建一个新的,所以每个帧都有一个新的请求,但我遇到了同样的问题。
非常感谢您对此的任何帮助。