能否为Microsoft HoloLens Spectator View Rig使用USB摄像头并修改OpenCV脚本？

Great question—you’re right that this is a relatively niche scenario for Spectator View, so let’s break this down step by step.

Can You Use a USB Camera with HoloLens Spectator View Rig? #

• Short answer: Yes, but you’ll need to check a few prerequisites first:
  • Make sure your USB camera is UWP-compatible (HoloLens runs UWP apps, so the camera must support the UWP Media Capture API).
  • Connect the camera to your HoloLens using a compatible adapter (USB-C for HoloLens 2, micro-USB adapter for HoloLens 1).
  • In your Unity project, enable critical capabilities under Player Settings > UWP > Publishing Settings: check Webcam (and Microphone if your camera has audio) to grant access to external devices.

Modifying OpenCV Script for USB Camera Capture #

Assuming you’re using the OpenCV for Unity package, here’s how to tweak your capture script to target the USB camera instead of HoloLens’s built-in sensor:

1. Locate your capture script (common examples include WebCamTextureToMatHelper.cs or a custom frame-capture script you’ve built).
2. Adjust camera selection logic:
   By default, OpenCV for Unity often picks the first available camera (HoloLens’s front-facing one). You’ll need to iterate through devices to find your USB camera:

   // Fetch all available webcams
   WebCamDevice[] devices = WebCamTexture.devices;
   WebCamDevice usbCamera = null;
   
   // Loop to identify the USB camera (adjust the condition to match your device's name)
   foreach (var device in devices)
   {
       // Skip HoloLens's built-in cameras (names usually include "HoloLens" or "Front")
       if (!device.name.Contains("HoloLens") && !device.name.Contains("Front"))
       {
           usbCamera = device;
           break;
       }
   }
   
   if (usbCamera != null)
   {
       // Initialize capture with the USB camera (adjust resolution/fps as needed)
       WebCamTexture webcamTexture = new WebCamTexture(usbCamera.name, 1280, 720, 30);
       webcamTexture.Play();
       // Proceed to convert the texture to an OpenCV Mat for processing
   }
   else
   {
       Debug.LogError("USB Camera not detected! Check device compatibility and connections.");
   }
   

3. Fix frame orientation (if needed):
   USB cameras often output frames in a different orientation than HoloLens’s built-in camera. Add this line to rotate the OpenCV Mat:

   // Rotate 90 degrees clockwise (adjust based on your camera's actual output)
   Core.Rotate(frameMat, frameMat, Core.ROTATE_90_CLOCKWISE);
   

4. Test on device: Deploy the app to your HoloLens and check the Unity Console logs to confirm the USB camera is being detected and frames are captured correctly.

Enabling Spectator View for Multi-HoloLens Unity UWP Apps #

Based on official guidelines and practical experience, here’s what you need to set up:

• Network sync: Ensure all HoloLens devices are connected to the same 5GHz Wi-Fi network (low latency is critical for smooth Spectator View).
• Spectator View package: Import the official Microsoft Spectator View package into your Unity project (via Package Manager or the official GitHub repo).
• Spatial anchor sharing: Use either Azure Spatial Anchors or HoloLens’s built-in Shared Spatial Anchors to sync the 3D coordinate space across devices:
  • For Azure Spatial Anchors: Create an Azure anchor resource, add your credentials to the Unity project, and configure anchor creation/retrieval logic.
• Role assignment: Designate one HoloLens as the "Host" (capturing and streaming content) and others as "Spectators" (receiving and rendering the synced view).
• Deployment configuration: For each device, build the UWP app with these enabled capabilities: InternetClient, InternetClientServer, PrivateNetworkClientServer, SpatialPerception. Target ARM64 for HoloLens 2 or x86 for HoloLens 1.

If you hit specific snags—like camera detection issues or script errors—feel free to share more details, and I can help troubleshoot further!

内容的提问来源于stack exchange，提问作者user9236834