ios – 动态添加图像到AR资源以进行图像识别

ARKit 1.5引入了图像识别功能.在代码中,您必须创建一组参考图像,如下所示：

let referenceImages = ARReferenceImage.referenceImages(inGroupNamed: "AR Resources",bundle: nil)

然后可以识别集合中包含的图像.

我想知道是否可以动态添加图像到此AR Resources文件夹.例如,用户可以拍照并将其发送到服务器,然后由ARKit识别.或者用户可以根据他的位置等接收一组图像.

解决方法

尽管您可以动态创建图像,但无法在运行时修改默认文件夹的内容.

举个例子,让我们把一个图像放到Assets文件夹(而不是ARResources文件夹)中,在我的例子中称为’moonTarget’.

然后我们可以创建一个我们在viewDidLoad等中调用的函数：

/// Create ARReference Images From Somewhere Other Than The Default Folder
func loadDynamicImageReferences(){

    //1. Get The Image From The Folder
    guard let imageFromBundle = UIImage(named: "moonTarget"),//2. Convert It To A CIImage
    let imageToCIImage = CIImage(image: imageFromBundle),//3. Then Convert The CIImage To A CGImage
    let cgImage = convertCIImageToCGImage(inputImage: imageToCIImage)else { return }

    //4. Create An ARReference Image (Remembering Physical Width Is In Metres)
    let arImage = ARReferenceImage(cgImage,orientation: CGImagePropertyOrientation.up,physicalWidth: 0.2)

    //5. Name The Image
    arImage.name = "CGImage Test"

    //5. Set The ARWorldTrackingConfiguration Detection Images
    configuration.detectionImages = [arImage]
}


/// Converts A CIImage To A CGImage
///
/// - Parameter inputImage: CIImage
/// - Returns: CGImage
func convertCIImageToCGImage(inputImage: CIImage) -> CGImage? {
    let context = CIContext(options: nil)
    if let cgImage = context.createCGImage(inputImage,from: inputImage.extent) {
     return cgImage
    }
    return nil
}

然后我们可以在ARSCNViewDelegate中测试它：

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

    //1. If Out Target Image Has Been Detected Than Get The Corresponding Anchor
    guard let currentImageAnchor = anchor as? ARImageAnchor else { return }

    let x = currentImageAnchor.transform
    print(x.columns.3.x,x.columns.3.y,x.columns.3.z)

    //2. Get The Targets Name
    let name = currentImageAnchor.referenceImage.name!

    //3. Get The Targets Width & Height In Meters
    let width = currentImageAnchor.referenceImage.physicalSize.width
    let height = currentImageAnchor.referenceImage.physicalSize.height

    print("""
    Image Name = \(name)
    Image Width = \(width)
    Image Height = \(height)
    """)

    //4. Create A Plane Geometry To Cover The ARImageAnchor
    let planeNode = SCNNode()
    let planeGeometry = SCNPlane(width: width,height: height)
    planeGeometry.firstMaterial?.diffuse.contents = UIColor.white
    planeNode.opacity = 0.25
    planeNode.geometry = planeGeometry

    //5. Rotate The PlaneNode To Horizontal
    planeNode.eulerAngles.x = -.pi/2

    //The Node Is Centered In The Anchor (0,0)
    node.addChildNode(planeNode)

    //6. Create AN SCNBox
    let boxNode = SCNNode()
    let boxGeometry = SCNBox(width: 0.1,height: 0.1,length: 0.1,chamferRadius: 0)

    //7. Create A Different Colour For Each Face
    let faceColours = [UIColor.red,UIColor.green,UIColor.blue,UIColor.cyan,UIColor.yellow,UIColor.gray]
    var faceMaterials = [SCNMaterial]()

    //8. Apply It To Each Face
    for face in 0 ..< 5{
        let material = SCNMaterial()
        material.diffuse.contents = faceColours[face]
        faceMaterials.append(material)
    }
    boxGeometry.materials = faceMaterials
    boxNode.geometry = boxGeometry

    //9. Set The Boxes Position To Be Placed On The Plane (node.x + box.height)
    boxNode.position = SCNVector3(0,0.05,0)

    //10. Add The Box To The Node
    node.addChildNode(boxNode)   
}

正如您所看到的,也可以从实时馈送中应用相同的内容.

希望这可以帮助…

正如@Karlis所说,您还可以查看使用OnDemandResouces,然后将它们转换为ARReferenceImage的所需规格.