Registering virtual and real worlds with rt-xr, ARKit and Unity


One of the goals for rt-xr is to allow augmented reality users within a space to collaborate with virtual reality users physically outside of the space, with the VR users getting a telepresent sense of being physically within the same space. To this end, VR users see a complete model of the space (my office in this case) including augmentations while physically present AR users just see the augmentations. Some examples of augmentations are virtual whiteboards and virtual sticky notes. Both AR and VR users see avatars representing the position and pose of other users in the space.

Achieving this for AR users requires that their coordinate system corresponds with that of the virtual models of the room. For iOS, ARKit goes a long way to achieving this so the rt-xr app for iOS has been extended to include ARKit and work in AR mode. The screen capture above shows how coordinate systems are synced. A known location in physical space (in this case, the center of the circular control of the fan controller) is selected by touching the iPad screen on the exact center of the control. This identifies position. To avoid multiple control points, the app is currently started in the correct pose so that the yaw rotation is zero relative to the model origin. It is pretty quick and easy to do. The video below shows the process and the result.

After starting the app in the correct orientation, the user is then free to move to click on the control point. Once that’s done, the rt-xr part of the app starts up and loads the virtual model of the room. For this test, the complete model is being shown (i.e. as for VR users rather than AR users) although in real life only the augmentations would be visible – the idea here was to see how the windows lined up. The results are not too bad all things considered although moving or rotating too fast can cause some drift. However, collaborating using augmentations can tolerate some offset so this should not be a major problem.

There are just a couple of augmentations in this test. One is the menu switch (the glowing M) which is used to instantiate and control augmentations. There is also a video screen showing the snowy scene from the driveway camera, the feed being generated by an rt-ai design.

Next step is to test out VR and AR collaboration properly by displaying the correct AR scene on the iOS app. Since VR collaboration has worked for some time, extending it to AR users should not be too hard.

The ZeroSensor – a sentient space point of presence

One application for rt-ai Edge is ubiquitous sensing leading to sentient spaces – spaces that can interact with people moving through and provide useful functionality, whether learned or programmed. A step on the road to that is the ZeroSensor, four prototypes of which are shown in the photo. Each ZeroSensor consists of a Raspberry Pi Zero W, a Pi camera module v2, an Adafruit BME 680 breakout and an Adafruit TSL2561 breakout. The combination gives a video stream and a sensor stream with light, temperature, pressure, humidity and air quality values. The video stream can be used to derive motion sensing and identification while the other sensors provide a general idea of conditions in the space. Notably missing is audio. Microphone support would be useful for general sensing and I might add that in real devices. A 3D printable case design is underway in order to allow wide-scale deployment.

Voice-based interaction is a powerful way for users to interact with sentient spaces. However, it is assumed that people who want to interact are using an AR headset of some sort which itself provides the audio I/O capabilities. Gesture input would be possible via the ZeroSensor’s camera. For privacy reasons video would not be viewed directly or stored but just used as a source of activity data and interaction.

This is the simple rt-ai design used to test the ZeroSensors. The ZeroSynth modules are rt-ai Edge synth modules that contain SPEs that interface with the ZeroSensor’s hardware and generate a video stream and a sensor data stream. An instance of a video viewer and sensor viewer are connected to each ZeroSynth module.

This is the result of running the ZeroSensor test design, showing a video and sensor window for each ZeroSensor. The cameras are staring at the ceiling because the four sensors were on a table. When the correct case is available, they will be deployed in the corners of rooms in the space.

The AwareSpace project

The earlier Smart space post got me thinking about other related projects and I came across these old screen captures from the AwareSpace project. This was a much more serious attempt to make use of ubiquitous sensor data. It worked fine, giving easy access to real time and historic data from sensors. There was even web access to the system. Like many projects, it was never really finished and needed a lot more work to do everything that I wanted. One day…

Smart spaces and IoT data – the challenge is what to do with it

A while back I built some add-on cards for Raspberry Pis to do some environmental monitoring around the house. This is one of them.

The project starting collecting dust when I couldn’t really think of good ways of using the data, beyond triggering an alarm under some conditions or something. However, it’s often interesting just to see what’s going on around the place so I have revived the sensors (a good use for old first generation Pis). The screen capture shows a simple but actually quite effective way of using the data that’s being generated, providing a display that’s adjacent to the camera feed from a webcam on the same Pi. Between the two streams, you can get good confidence on what’s happening in the smart space.

One day, I’d like to get the HoloLens integrated with this so that I can see the data when I am in the smart space. That would be even more fun.