使用ARCore/ARKit基于标记的初始定位? [英] Marker based initial positioning with ARCore/ARKit?

问题描述

问题状况:始终以舒适的方式在同一位置(在桌子上)创建AR可视化.我们不希望客户像无数ARCore/ARKit示例中那样放置对象本身.

我想知道是否有一种方法可以实现这些步骤:

1. 检测桌子上的标记
2. 使用标记的位置作为AR-Visualization的初始位置，然后继续SLAM-Tracking

我知道TangoSDK的最新版本中包含类似Marker-Detection API的东西.但是，这项技术仅限于少量设备(确切地说是两个).

最诚挚的问候，并感谢您的任何想法

解决方案

这是到目前为止我对ARKit的了解.

@objc func tap(_ sender: UITapGestureRecognizer){
    let touchLocation = sender.location(in: sceneView)
    let hitTestResult = sceneView.hitTest(touchLocation, types: .featurePoint)

    if let hitResult = hitTestResult.first{
        if first == nil{
            first = SCNVector3Make(hitResult.worldTransform.columns.3.x, hitResult.worldTransform.columns.3.y, hitResult.worldTransform.columns.3.z)
        }else if second == nil{
            second = SCNVector3Make(hitResult.worldTransform.columns.3.x, hitResult.worldTransform.columns.3.y, hitResult.worldTransform.columns.3.z)
        }else{
            third = SCNVector3Make(hitResult.worldTransform.columns.3.x, hitResult.worldTransform.columns.3.y, hitResult.worldTransform.columns.3.z)

            let x2 = first!.x
            let z2 = -first!.z
            let x1 = second!.x
            let z1 = -second!.z
            let z3 = -third!.z

            let m = (z1-z2)/(x1-x2)
            var a = atan(m)

            if (x1 < 0 && z1 < 0){
                a = a + (Float.pi*2)
            }else if(x1 > 0 && z1 < 0){
                a = a - (Float.pi*2)
            }

            sceneView.scene.rootNode.addChildNode(yourNode)
            let rotate = SCNAction.rotateBy(x: 0, y: CGFloat(a), z: 0, duration: 0.1)
            yourNode.runAction(rotate)
            yourNode.position = first!

            if z3 - z1 < 0{
                let rotate = SCNAction.rotateBy(x: 0, y: CGFloat.pi, z: 0, duration: 0.1)
                yourNode.runAction(rotate)
            }
        }
    }
}

理论是:
制作三个点A，B，C，使AB垂直于AC.点按A-B-C顺序点.
在ARSceneView的x = 0中找到AB的角度，该角度为节点提供了所需的旋转.
任意一个点都可以求值以计算放置节点的位置.
从C中查找是否需要翻转节点.

我仍在处理一些需要满足的例外情况.

problem situation: Creating AR-Visualizations always at the same place (on a table) in a comfortable way. We don't want the customer to place the objects themselves like in countless ARCore/ARKit examples.

I'm wondering if there is a way to implement those steps:

1. Detect marker on the table
2. Use the position of the marker as the initial position of the AR-Visualization and go on with SLAM-Tracking

I know there is something like an Marker-Detection API included in the latest build of the TangoSDK. But this technology is limited to a small amount of devices (two to be exact...).

best regards and thanks in advance for any idea

解决方案

This is what i got so far for ARKit.

@objc func tap(_ sender: UITapGestureRecognizer){
    let touchLocation = sender.location(in: sceneView)
    let hitTestResult = sceneView.hitTest(touchLocation, types: .featurePoint)

    if let hitResult = hitTestResult.first{
        if first == nil{
            first = SCNVector3Make(hitResult.worldTransform.columns.3.x, hitResult.worldTransform.columns.3.y, hitResult.worldTransform.columns.3.z)
        }else if second == nil{
            second = SCNVector3Make(hitResult.worldTransform.columns.3.x, hitResult.worldTransform.columns.3.y, hitResult.worldTransform.columns.3.z)
        }else{
            third = SCNVector3Make(hitResult.worldTransform.columns.3.x, hitResult.worldTransform.columns.3.y, hitResult.worldTransform.columns.3.z)

            let x2 = first!.x
            let z2 = -first!.z
            let x1 = second!.x
            let z1 = -second!.z
            let z3 = -third!.z

            let m = (z1-z2)/(x1-x2)
            var a = atan(m)

            if (x1 < 0 && z1 < 0){
                a = a + (Float.pi*2)
            }else if(x1 > 0 && z1 < 0){
                a = a - (Float.pi*2)
            }

            sceneView.scene.rootNode.addChildNode(yourNode)
            let rotate = SCNAction.rotateBy(x: 0, y: CGFloat(a), z: 0, duration: 0.1)
            yourNode.runAction(rotate)
            yourNode.position = first!

            if z3 - z1 < 0{
                let rotate = SCNAction.rotateBy(x: 0, y: CGFloat.pi, z: 0, duration: 0.1)
                yourNode.runAction(rotate)
            }
        }
    }
}

Theory is:
Make three dots A,B,C such that AB is perpendicular to AC. Tap dots in order A-B-C.
Find angle of AB in x=0 of ARSceneView which gives required rotation for node.
Any one of the point can be refrenced to calculate position to place node.
From C find if node needs to be flipped.

I am still working on some exceptions that needs to be satisfied.

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