ARKit 2 - 作物识别图像答案

【问题标题】：ARKit 2 - Crop Recognizing ImagesARKit 2 - 作物识别图像
【发布时间】：2018-11-27 00:18:48
【问题描述】：

所以，我的目标是：

查找已知图像

guard let referenceImages = ARReferenceImage.referenceImages(inGroupNamed: "AR Resources", bundle: nil) else { return }

let configuration = ARWorldTrackingConfiguration()
configuration.detectionImages = referenceImages

从场景视图中拍摄快照

 func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {

       let image = sceneView.snapshot()  //  or else self.sceneView.session.currentFrame?.capturedImage

我需要从 SceneView 中提取图像。

这是我的代码，我正在使用 renderer.projectPoint 方法。

  guard let imageAnchor = anchor as? ARImageAnchor else {
            return
        }
        let posx = anchorTr.x// fnode.convertPosition(node.position, to: node).x //self.positionFromTransform(node.simdTransform).x// node.simdTransform.columns.3.x
        let posy = anchorTr.y//fnode.convertPosition(node.position, to: node).y //self.positionFromTransform(node.simdTransform).y//node.simdTransform.columns.3.y
        let posz = anchorTr.z //node.simdTransform.columns.3.z


                  let width = referenceImage.physicalSize.width
        let height = referenceImage.physicalSize.height


        let topLeftPosition = SCNVector3(posx - Float(width / 2), posy - Float(height / 2), posz )
        let topRightPosition = SCNVector3(posx + Float(width / 2), posy - Float(height / 2), posz )
        let bottomLeftPosition = SCNVector3(posx - Float(width / 2), posy + Float(height / 2), posz )
        let bottomRightPosition = SCNVector3(posx + Float(width / 2), posy  + Float(height / 2), posz)


        let topLeftProjection = renderer.projectPoint(topLeftPosition)
        let topRightProjection = '''
        let bottomLeftProjection = '''
        let bottomRightProjection = '''

        let topLeft = CGPoint(x: CGFloat(topLeftProjection.x), y: CGFloat( topLeftProjection.y))
        let topRight = ''
        let bottomLeft = ''''''
        let bottomRight = '''


  let points = [topLeft, topRight, bottomRight, bottomLeft]

   self.drawPolygon(points, color:.green)

但是这个方法好像是依赖手机的位置。

【问题讨论】：

“我想 ”帖子不太适合这个网站。该站点用于获取有关您已经编写的代码的调试帮助。

标签： ios swift arkit

【解决方案1】：

就我而言，我通过对每个参考点执行此操作来解决它。

let transform = node.simdConvertTransform(node.simdTransform, to: node.parent!)

let x = transform.columns.3.x
let y = transform.columns.3.y
let z = transform.columns.3.z

let position = SCNVector3(x, y, z)
let projection = renderer.projectPoint(position)

let screenPoint =  CGPoint(x: CGFloat(projection.x), y: CGFloat( projection.y))

【讨论】：

它对我不起作用......尊重第一个解决方案也更不稳定。