One of the goals of the rt-ai Edge system is that users of the system can use whatever device they have available to interact and extract value from it. Unity is a tremendous help given that Unity apps can be run on pretty much everything. The main task was integration with Manifold so that all apps can receive and interact with everything else in the system. Manifold currently supports Windows, UWP, Linux, Android and macOS. iOS is a notable absentee and will hopefully be added at some point in the future. However, I perceive Android support as more significant as it also leads to multiple MR headset support.
The screen shot above and video below show three instances of the rt-ai viewer apps running on Windows desktop, Windows Mixed Reality and Android interacting in a shared sentient space. Ok, so the avatars are rubbish (I call them Sad Robots) but that’s just a detail and can be improved later. The wall panels are receiving sensor and video data from ZeroSensors via an rt-ai Edge stream processing network while the light switch is operated via a home automation server and Insteon.
Sharing is mediated by a SharingServer that is part of Manifold. The SharingServer uses Manifold multicast and end to end services to implement scalable sharing while minimizing the load on each individual device. Ultimately, the SharingServer will also download the space definition file when the user enters a sentient space and also provide details of virtual objects that may have been placed in the space by other users. This allows a new user with a standard app to enter a space and quickly create a view of the sentient space consistent with existing users.
While this is all kind of fun, the more interesting thing is when this is combined with a HoloLens or similar MR headset. The MR headset user in a space would see any VR users in the space represented by their avatars. Likewise, VR users in a space would see avatars representing MR users in the space. The idea is to get as close to a telepresent experience for VR users as possible without very complex setups. It would be much nicer to use Holoportation but that would require every room in the space has a very complex and expensive setup which really isn’t the point. The idea is to make it very easy and low cost to implement an rt-ai Edge based sentient space.
Still lots to do of course. One big thing is audio. Another is representing interaction devices (pointers, motion controllers etc) to all users. Right now, each app just sends out the camera transform to the SharingServer which then distributes this to all other users. This will be extended to include PCM audio chunks and transforms for interaction devices so that everyone will be able to create a meaningful scene. Each user will receive the audio stream from every other user. The reason for this is that then each individual audio stream can be attached to the avatar for each user giving a spatialized sound effect using Unity capabilities (that’s the hope anyway). Another very important thing is that the apps work differently if they are running on VR type devices or AR/MR type devices. In the latter case, the walls and related objects are not drawn and just the colliders instantiated although virtual objects and avatars will be visible. Obviously AR/MR users want to see the real walls, light switches etc, not the virtual representations. However, they will still be able to interact in exactly the same way as a VR user.
Found this old (from January 2013) and rather dull video of me driving a robot using the touchscreen on an Android tablet. It came to mind because the current project is using some of the software originally developed for this.
The glove controlled robot worked a lot better 🙂
Since the ability operate a real light switch from the VR world using Windows Mixed Reality (WMR) is now working, it was time to get to get the same thing working on the Android version of the Unity app – rtAndroidView. This uses the same rt-ai Edge stream processing network and Manifold network as the WMR and desktop versions but the extra trick was to get the interaction working.
The video shows me using the touch screen to navigate around the virtual model of my office and operate the light switch, showing that the Manifold HAServer interface is working, along with the normal video and ZeroSensor interfaces.
This is using the Android device as a VR device. In theory, it should be possible to use ARCore with an AR version of this app but the issue is locking the virtual space to the real space. That will take some experimentation I suspect.
Having now constructed a simple walk around model of my office and another room, it was time to start work on the interaction side of things. I have an Insteon switch controlling some of the lights in my office and this seemed like an obvious target. Manifold now has a home automation server app (HAServer) based on one from an earlier project. This allows individual Insteon devices to be addressed by user-friendly names using JSON over Manifold’s end to end datagram service. Light switches can now be specified in the Unity rtXRView space definition file and linked to the control interface of the HAServer.
The screen capture above and video below were made using a Samsung Odyssey headset and motion controllers. The light switch specification causes a virtual light switch to be placed, ideally exactly where the real light switch happens to be. Then, by pointing at the light switch with the motion controller and clicking, the light can be turned on and off. The virtual light switch is gray when the light is off and green when it is on. If the real switch is operated by some other means, the virtual light switch will reflect this as the HAServer broadcasts state change updates on a regular basis. It’s nice to see that the light sensor on the ZeroSensor responds appropriately to the light level too. Technically this light switch is a dimmer – setting an intermediate level is a TODO at this point.
An interesting aspect of this is the extent to which a remote VR user can get a sense of telepresence in a space, even if it is just a virtual representation of the real space. To make that connection more concrete, the virtual light in Unity should reflect the ambient light level as measured by the ZeroSensor. That’s another TODO…
While this is kind of fun in the VR world, it could actually be interesting in the AR world. If the virtual light switch is placed correctly but is invisible (apart from a collider), a HoloLens user (for example) could look at a real light switch and click in order to change the state of the switch. Very handy for the terminally lazy! More useful than just this would be to annotate the switch with what it controls. For some reason, people in this house never seem to know which light switch controls what so this feature by itself would be quite handy.
These days, machine learning techniques have led to the ability to create very realistic but fake video and audio that can be tough to distinguish from the real thing. The video above shows a very interesting example of this capability. The problem with this technology is that it will become impossible to determine if anything is genuine at all. What’s needed is some verification that a video of someone (for example) really is that person. Blockchain technology would seem to provide a solution for this.
Many years ago I was working on a digital watermarking-based system for detecting tampering in video records. Essentially, this embedded error-correcting codes in each frame that could be used to determine if any region of a frame had been modified after the digital watermark had been added. Cameras would add the digital watermark at source, limiting the opportunity for modification prior to watermarking.
One problem with this is that it worked on a frame by frame basis but didn’t ensure the integrity of an entire sequence. In theory this could be done with temporally distributed watermarks but blockchain technology provides a very nice alternative.
A simple strategy would be to have the sensor (camera, microphone, motion detector, whatever) create a hash for each unit of data (video frame, chunk of audio etc) and add this to a blockchain. Then a review app could create new hashes from the sensor data itself (stored elsewhere) and compare them to those in the blockchain. It could also determine that the account owner or device is who or what it is supposed to be in order to avoid spoofing. It’s easy to envisage an Etherium smart contract being the basis of such a system.
One issue with this is the potential rate at which hashes need to be added to the blockchain. This rate could be reduce by collecting more data (e.g. accumulating one second’s worth of data to generate one hash) or creating a hash of hashes at an appropriate rate. The only downside to this is losing temporal resolution of where changes have been made.
It’s worth considering the effects of lossy compression. Obviously if a stream is uncompressed or only uses lossless compression, watermarking and hash generation can be done at a very early stage. Watermarking of video is designed to withstand compression so that can still be done at a very early stage, even with lossy compression. The hash has to be be bit-accurate with the stream as stored on the video storage medium though so the hash must be computed after lossy compression.
It seems as though this blockchain concept could definitely be made to work and possibly combined with the digital watermarking technique in the case of video to provide temporal and spatial resolution of tampering. I am sure that variations of this concept are out there already or being developed and maybe, one day, it will be possible for anybody to check if a video of a well-known person is real or fake.
The screen capture above and video below are from a walk-through of a procedurally generated sentient space model with video and IoT data displays (derived from ZeroSensor data, rt-ai Edge and Manifold). This was made using rt3DView and the actual Unity video recording made with the aid of this very nice Unity store asset.
The idea of this model is that it reflects the major features of the real sentient space so that users of VR and AR can interact correctly. For example, an AR headset wearer in one of the rooms would also see the displays on the equivalent physical wall. This model is pretty basic but obviously a lot more bling could be added to get further along the road to realism. Plus I made no attempt to sort out the exterior for this test.
Now that the basics are working and the XR world is fully coupled to the rt-ai Edge design that is the real world element of the sentient space, the focus will move to more interaction. Instantiating new objects, positioning objects, real-time sharing of camera poses leading to avatars… The list is endless.
Continue reading “A virtual walk through a sentient space with rt3DView”
The Windows Mixed Reality version of 3DView is now working nicely. Had a few problems with my Windows development PC which is a few years old and didn’t have adequate USB ports. In the end this PCI-e USB 3.1 card solved that problem otherwise a complete upgrade might have been required. A different USB 3.0 card did not work however.
Hopefully this is the last time that I see the displays all lined up like that. The space modeling software is coming along and soon it will be possible to model a space with a (relatively) simple procedural definition file. Potentially this could be texture mapped from a 3D scan of rooms but the simplified models generated procedurally with simple textures might well be good enough. Then it will be possible to position versions of these displays (and lots of other things) in the correct rooms.
XRView is intended to be runnable both on Windows MR headsets (I am using the Samsung Odyssey as it has a good display and built-in audio) and HoloLens. Now clearly VR modes and AR modes have to be completely different. In VR, you navigate and interact with the motion controllers and see the modeled space whereas in AR you navigate by walking around, interact using the clicker and don’t see the modeled space directly. However, the modeled space will still be there and will be used instead of the spatially mapped surfaces that the HoloLens might normally use. This means that objects placed in the model by a VR user will appear to AR users correctly positioned and vice versa. One key advantage of using the modeled space rather than the dynamically mapped space generated by the HoloLens itself is that it is easy to add context to the surfaces using the procedural model language. Another is the ability to interwork with non-HoloLens AR headsets that can share the HoloLens spatial map data. The procedural model becomes a platform-independent spatial mapping that “just” leaves the problem of spatial synchronization to the individual headsets.
I am sure that there will be some fun challenges in getting spatial synchronization but that’s something for later.