AR相机测距

Question

我有一个关于AR(增强现实)的问题。

我想知道如何显示距离信息(如中心仪...)AR相机和目标对象之间的距离。(使用智能手机)

我可以在Unity中这样做吗？我应该使用AR Foundation吗？那ARcore呢？如何编写代码？

我试着找到一些相关的代码(如下)，但它似乎只是打印对象和对象之间的信息，没有关于"AR相机“…

var other : Transform;
if (other) {
    var dist = Vector3.Distance(other.position, transform.position);
    print ("Distance to other: " + dist);
}

再次感谢！

Answer 1

下面是Unity和AR Foundation 4.1的使用方法。此示例脚本在depth纹理的中心打印以米为单位的深度，并同时适用于ARCore和ARKit：

using System;
using System.Collections;
using UnityEngine;
using UnityEngine.Assertions;
using UnityEngine.XR.ARFoundation;
using UnityEngine.XR.ARSubsystems;


public class GetDepthOfCenterPixel : MonoBehaviour {
    // assign this field in inspector
    [SerializeField] AROcclusionManager manager = null;
    
    
    IEnumerator Start() {
        while (ARSession.state < ARSessionState.SessionInitializing) {
            // manager.descriptor.supportsEnvironmentDepthImage will return a correct value if ARSession.state >= ARSessionState.SessionInitializing 
            yield return null;
        }
        
        if (!manager.descriptor.supportsEnvironmentDepthImage) {
            Debug.LogError("!manager.descriptor.supportsEnvironmentDepthImage");
            yield break;
        }
        
        while (true) {
            if (manager.TryAcquireEnvironmentDepthCpuImage(out var cpuImage) && cpuImage.valid) {
                using (cpuImage) {
                    Assert.IsTrue(cpuImage.planeCount == 1);
                    var plane = cpuImage.GetPlane(0);
                    var dataLength = plane.data.Length;
                    var pixelStride = plane.pixelStride;
                    var rowStride = plane.rowStride;
                    Assert.AreEqual(0, dataLength % rowStride, "dataLength should be divisible by rowStride without a remainder");
                    Assert.AreEqual(0, rowStride % pixelStride, "rowStride should be divisible by pixelStride without a remainder");

                    var numOfRows = dataLength / rowStride;
                    var centerRowIndex = numOfRows / 2;
                    var centerPixelIndex = rowStride / (pixelStride * 2);
                    var centerPixelData = plane.data.GetSubArray(centerRowIndex * rowStride + centerPixelIndex * pixelStride, pixelStride);
                    var depthInMeters = convertPixelDataToDistanceInMeters(centerPixelData.ToArray(), cpuImage.format);
                    print($"depth texture size: ({cpuImage.width},{cpuImage.height}), pixelStride: {pixelStride}, rowStride: {rowStride}, pixel pos: ({centerPixelIndex}, {centerRowIndex}), depthInMeters of the center pixel: {depthInMeters}");
                }
            }
            
            yield return null;
        }
    }

    float convertPixelDataToDistanceInMeters(byte[] data, XRCpuImage.Format format) {
        switch (format) {
            case XRCpuImage.Format.DepthUint16:
                return BitConverter.ToUInt16(data, 0) / 1000f;
            case XRCpuImage.Format.DepthFloat32:
                return BitConverter.ToSingle(data, 0);
            default:
                throw new Exception($"Format not supported: {format}");
        }
    }
}

Answer 2

我也在做AR深度图像，基本的想法是：

1. Acquire一个图像使用接口，通常它的格式是将图像到短缓冲区，因为Depth16意味着每个像素是16个短缓冲区的距离值，这是存储在每个短缓冲区的低13位，你可以这样做( Depth16;
2. Split & 0x1ff)，然后你就可以得到每个像素的距离，通常是在millimeters.

中

通过对所有像素执行此操作，您可以创建深度图像并将其存储为jpg或其他格式，以下是使用AR引擎获取距离的示例代码：

try (Image depthImage = arFrame.acquireDepthImage()) {
        int imwidth = depthImage.getWidth();
        int imheight = depthImage.getHeight();
        Image.Plane plane = depthImage.getPlanes()[0];
        ShortBuffer shortDepthBuffer = plane.getBuffer().asShortBuffer();
        File sdCardFile = Environment.getExternalStorageDirectory();
        Log.i(TAG, "The storage path is " + sdCardFile);
        File file = new File(sdCardFile, "RawdepthImage.jpg");

        Bitmap disBitmap = Bitmap.createBitmap(imwidth, imheight, Bitmap.Config.RGB_565);
        for (int i = 0; i < imheight; i++) {
            for (int j = 0; j < imwidth; j++) {
                int index = (i * imwidth + j) ;
                shortDepthBuffer.position(index);
                short depthSample = shortDepthBuffer.get();
                short depthRange = (short) (depthSample & 0x1FFF);
                //If you only want the distance value, here it is
                byte value = (byte) depthRange;
          byte value = (byte) depthRange ;
                disBitmap.setPixel(j, i, Color.rgb(value, value, value));
            }
        }
        //I rotate the image for a better view
        Matrix matrix = new Matrix();
        matrix.setRotate(90);
        Bitmap rotatedBitmap = Bitmap.createBitmap(disBitmap, 0, 0, imwidth, imheight, matrix, true);

        try {
            FileOutputStream out = new FileOutputStream(file);
            rotatedBitmap.compress(Bitmap.CompressFormat.JPEG, 90, out);
            out.flush();
            out.close();
            MainActivity.num++;
        } catch (Exception e) {
            e.printStackTrace();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Answer 3

虽然答案很好，但对于这个问题来说，它们可能太复杂和高级了，这个问题是关于ARCamera和另一个对象之间的距离，而不是关于像素的深度和它们的遮挡。

transform.position为您提供在层次中附加脚本的任何游戏对象的位置。因此，将脚本附加到ARCamera对象。显然，other应该是目标对象。

或者，您可以使用检查器变量或GetComponent获取对这两个游戏对象的引用