How does the future data interface look like? A bet from Google is that it will involve invisible interfaces you can tweak and twiddle in the middle of the air. This is what the company is exploring through Project Soli, an experimental hardware program that uses miniature radar to detect motion, and recently won FCC approval for further study.
Imagining just how this technology will be used is difficult, but a group of researchers from St Andrews University in Scotland explores the limitations. In a paper published last month, they show how Project Soli hardware can be used for a variety of accurate sensing tasks. These include counting the number of playing cards in a deck, measuring compass orientation, and even discerning the specific configuration of a stack of Lego bricks.
All this is done using the delicate radar readings from Google's hardware, which scientists incorporate into a system they call RadarCat. As with radars used to detect aircraft, the sensors burn harmless electromagnetic pulses in a target, some of which are bouncing back. The way these pulses return varies based on various factors, including distance, object density, thickness, shape and surface properties.
Combined, these elements create a unique radar fingerprint for each element. The team's previous work, released in 2016, showed how this approach could be used to recognize different objects, and their latest work – a technique they call Solar Interaction – goes even further to produce more nuanced sensing results.
Speaking to The Verge said researcher Hui-Shyong Yeo the new technique enables all sorts of cases of extra use. "The sensing technique remains quite similar [but] The main contribution is the great exploration of […] counting, ordering, stacking, moving and orienting different objects, such as cards and legos."
The researchers suggest a variety of applications, for education, entertainment and more. Soli radars can be embedded in tabletops to recognize board games, for example, or built into smart homes to monitor the presence (or absence) of certain items.
Although these tasks can be achieved by other methods, the use of radar has unique advantages. For example, unlike RFID chips, it is not necessary to change the object you want to monitor. And unlike object recognition using cameras, there are no privacy issues, or need to maintain point of view or good lighting conditions. Radar works through different materials and in the dark and light.
There are, of course, limitations, including some caused by the high sensitivity of the radar readings themselves. Their delicacy means that small changes in the target can make it unknown. For example, the researchers found that when counting playing cards, the radar would misclassify the card if it was slightly bent.
It is not clear which uses Google will pursue with Project Soli, but research like this shows that there are a great many ways to explore.