Question

我试图在全局坐标中的3D空间中获取相机的位置。

override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        sceneView.delegate = self
        sceneView.showsStatistics = true
        sceneView.session.delegate = self
    }

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    // Create a session configuration with plane detection
    let configuration = ARWorldTrackingConfiguration()
    configuration.worldAlignment = .gravityAndHeading
    // Run the view's session
    sceneView.session.run(configuration)
}

func session(_ session: ARSession, didUpdate frame: ARFrame) {
        print(frame.camera.transform)
    }

我运行上面的代码，下面是我得到的示例输出

可选（simd_float4x4（[[ - 0.739868，-0.052769，-0.670678,0.0）]， [-0.569322,0.580241,0.582402,0.0）]，[0.358422,0.812733，-0.459345， 0.0）]，[0.0,0.0,0.0,1.0）]]））可选（simd_float4x4（[[ - 0.790284，-0.0315036，-0.611929,0.0）]，[ - 0.510883,0.585261,0.629656,0.0）]，[0.338302 ，0.810233，-0.478617,0.0）]，[0.0,0.0,0.0,1.0）]]））可选（simd_float4x4（[[ - 0.828626，-0.0174089，-0.559531,0.0）]， [-0.458209,0.595292,0.6660054,0.0）]，[0.321594,0.803321，-0.501252， 0.0）]，[0.0,0.0,0.0,1.0）]]））可选（simd_float4x4（[[ - 0.862658，-0.00656158，-0.505744,0.0）]，[ - 0.404869,0.608273,0.682703,0.0）]，[0.303151 ，0.793701，-0.527388,0.0）]，[0.0,0.0,0.0,1.0）]]））可选（simd_float4x4（[[ - 0.898201,0.0059859，-0.43954,0.0）]， [-0.337589,0.631021,0.69405,0.0）]，[0.28154,0.775742，-0.564764， 0.0）]，[0.0,0.0,0.0,1.0]]]））可选（simd_float4x4（[[ - 0.920434,0.0197568，-0.390395,0.0）]，[ - 0.284616,0.650707,0.703969,0.0）]，[0.267941， 0.759072，-0.593311,0.0）]，[0.0,0.0,0.0,1.0）]]））可选（simd_float4x4（[[ - 0.940432,0.041811，-0.337396,0.0）]， [-0.224465,0.666996,0.708559,0.0）]，[0.255342,0.7242089，-0.619762， 0.0）]，[0.0,0.0,0.0,1.0]]]））可选（simd_float4x4（[[ - 0.960581,0.0803864，-0.266119,0.0）]，[ - 0.1141218,0.683463,0.716193,0.0）]，[0.239455， 0.725546，-0.64517,0.0）]，[0.0,0.0,0.0,1.0）]]））可选（simd_float4x4（[[ - 0.969532,0.108638，-0.219551,0.0）]， [-0.0873999,0.683869,0.724349,0.0）]，[0.228836,0.721471， -0.653539,0.0）]，[0.0,0.0,0.0,1.0）]]））

如您所见，即使我正在移动手机，第4列始终为[0.0,0.0,0.0,1.0]。有人可以帮助我理解这个4x4矩阵（我认为这是相机旋转与全局坐标中的位置连接，即相机外部参数）。

Answer 1

可能需要一段时间（根据我的经验，在iPhone 7上为10-15秒），ARKit可以获得足够的相机/运动数据来提供位置跟踪;在那之前，它只能给你定位，并且位置将是 - 你正在观察 - （0,0,0）。要处理此问题，您可以实施session:cameraDidChangeTrackingState:方法并检查相机的trackingState - 当它从notAvailable或limited切换到normal时，您就可以开始使用位置数据。

Answer 2

我认为[0,0,0,1]是第4行，它始终保持不变。它只是一个填充行，使矩阵乘法很好地工作。

ARKit - 相机位置

2 个答案: