菜鸟教程小白 发表于 2022-12-11 20:15:00

ios - ARKit 1.5 : Extract the recognized image


                                            <p><p>所以，我的目标是:</p>

<ul>
<li>查找已知图片</li>
<li>从场景 View 中提取(例如拍摄快照)</li>
<li>执行进一步处理</li>
</ul>

<p>使用 <strong>ARReferenceImage</strong> 很容易完成第一步:</p>

<pre><code>guard let referenceImages = ARReferenceImage.referenceImages(inGroupNamed: &#34;AR Resources&#34;, bundle: nil) else { return }

let configuration = ARWorldTrackingConfiguration()

configuration.detectionImages = referenceImages
</code></pre>

<p>但现在我不知道如何从 SceneView 中提取图像。我已将平面节点添加到 imageAnchor:</p>

<pre><code>    func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
    DispatchQueue.main.async { in
      guard let imageAnchor = anchor as? ARImageAnchor
            else { return }

      let planeNode = self.getPlaneNode(withReferenceImage: imageAnchor.referenceImage)
      planeNode.opacity = 0.5
      planeNode.eulerAngles.x = -.pi / 2
      node.addChildNode(planeNode)
    }
}
</code></pre>

<p>结果:
<a href="/image/t9hYY.jpg" rel="noreferrer noopener nofollow"><img src="/image/t9hYY.jpg" alt="enter image description here"/></a> </p>

<p>所以，我需要planeNode 在屏幕上的<em>投影</em> 来获取节点的2D 屏幕坐标，然后剪切图像。我找到了这个方法: <code>renderer.projectPoint(node.position)</code> 但它对我没有帮助。当整个图片在屏幕上时，它甚至可以返回负值..</p>

<p>我的做法是否正确？任何帮助将不胜感激
.</p></p>
                                    <br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
                                            <p><p>就我而言，我解决了。</p>

<pre><code>    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))
</code></pre>

<p>更多信息</p>

<p> <a href="https://stackoverflow.com/questions/53453203/arkit-2-crop-recognizing-images" rel="noreferrer noopener nofollow">ARKit 2 - Crop Recognizing Images</a> </p>

<p> <a href="https://stackoverflow.com/questions/26526787/ios-8-core-image-saving-a-section-of-an-image-via-swift" rel="noreferrer noopener nofollow">iOS 8 Core Image saving a section of an Image via Swift</a> </p>

<p> <a href="https://nacho4d-nacho4d.blogspot.com/2012/03/coreimage-and-uikit-coordinates.html" rel="noreferrer noopener nofollow">https://nacho4d-nacho4d.blogspot.com/2012/03/coreimage-and-uikit-coordinates.html</a> </p></p>
                                   
                                                <p style="font-size: 20px;">关于ios - ARKit 1.5 : Extract the recognized image，我们在Stack Overflow上找到一个类似的问题：
                                                        <a href="https://stackoverflow.com/questions/50871959/" rel="noreferrer noopener nofollow" style="color: red;">
                                                                https://stackoverflow.com/questions/50871959/
                                                        </a>
                                                </p>
                                       
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