*Este artículo fue creado utilizando entrada de voz con IA (Aqua Voice). Tenga en cuenta que puede haber algunas inconsistencias.
How CPD Sensors Might Open the Door to Hardware-Less Full-Body Tracking
Hola. ¿Cómo están todos?
Soy Hiro del Laboratorio de Full Body Tracking.
Today I want to talk about the future of full-body tracking. And from a somewhat unexpected angle at that.
Do you all remember the news stories about toddlers being left behind in kindergarten transport buses? There were several tragic accidents in succession, and it became a major social issue. In response to those accidents, the automotive industry has been pushing forward with sensor development to make sure the same thing never happens again.
And this sensor technology might actually significantly change the future for us in the full-body tracking space.
Today, I’ll write about the name and mechanism of this technology, and its surprising connection to full-body tracking.
What Is a CPD Sensor?
Let me start with the technology itself.
CPD = Child Presence Detection. In plain English, it’s a “system for detecting children left inside vehicles.”
Automotive parts manufacturers are developing these CPD sensors. The goal is singular: to automatically detect whether a child has been left behind somewhere inside the vehicle when exiting, and to trigger an alert.
Never repeat those tragic accidents. That powerful motivation alone is accelerating this sensor development.
AISIN’s Efforts
Among Japanese automotive parts manufacturers, AISIN is seriously advancing CPD sensor development.
AISIN’s official blog has an article about wanting to protect tomorrow’s smiles through their child vehicle presence detection system, which provides a very thorough explanation of the development background and mechanism of this technology (article URL: https://www.aisin.com/jp/aithink/innovation/blog/005653.html).
According to the article, AISIN has been developing this sensor since 2018, with engineers from Japan, North America, and Europe collaborating. Their transport bus system already received certification from Japan’s Ministry of Land, Infrastructure, Transport and Tourism as of April 2023, and mandatory adoption has begun. A field trial has also been conducted at a kindergarten in Kariya City, Aichi Prefecture.
In other words, this isn’t something far off in the future. It’s technology that’s already in motion in the real world.
How It Works: Reading Body Information via Millimeter-Wave Radar
The mechanism of CPD sensors, broadly speaking, is a technology that wirelessly reads a child’s body information using millimeter-wave radar.
What surprised me most when reading AISIN’s article was the number of channels. While conventional millimeter-wave radar used about 3-4 transmit channels, AISIN’s CPD sensor uses “16 transmit channels and 19 receive channels.” That’s a dramatic leap in precision.
According to the article, this multi-channel approach enables three things:
- Dot data analysis: Recognizing objects as 3D-like images from reflected radio waves
- Micro-motion detection: Detecting chest movements from breathing to distinguish children from objects
- Wide-area coverage: A single sensor can cover up to three rows of seats
Cameras are weak when objects are hidden, and sonar struggles with detecting micro-movements. Given these challenges with both approaches, “identification of biological responses” via millimeter-wave radar represents a breakthrough-worthy advancement.
The Fact That “You Can Read the Body Without Attaching Anything”
I don’t claim to fully understand this technology, so I’ll leave the finer details to experts, but here’s the crucial point:
“You can wirelessly read information about a human body from a distance, without any devices attached.”
And it can detect movements as subtle as breathing. That single statement holds the entire future of full-body tracking within it.
Incidentally, in the United States, 1,083 people died from being left in vehicles between 1990 and 2023, and more than half were due to parents’ “carelessness.” Looking at these numbers, you can sense just how strong the motivation behind CPD sensor development is.
This Could Be Used for Full-Body Tracking
Now, here’s where it starts sounding like a Full Body Tracking Lab article.
“Wirelessly reading body information” — this is essentially the same thing we’re doing with full-body tracking.
Full-body tracking, as it stands today, is a technology where you “attach trackers to your body and track their position and orientation.” SteamVR base stations, IMU, Ultimate Tracker — there are various options, but the fundamental premise is “attaching sensors to your body.”
But if technology like CPD sensors can “wirelessly read body movement and position without attaching anything to the body,” then theoretically, there’s a possibility of doing full-body tracking without attaching trackers.
The Era of Hardware-Less Full-Body Tracking
Just imagine.
You place one small sensor in your room, and without attaching any trackers to your body, all your full-body movements are reflected on your avatar in VRChat. No calibration, no discomfort from wearing devices, no worrying about batteries dying. You just stand there and move, and full-body tracking is established.
This is the world of “hardware-less full-body tracking.”
Of course, this is still in the realm of dreams. It’s not something that will happen right away. But as technology for “wirelessly reading the human body” like CPD sensors matures, this vision has a real chance of becoming reality.
Similar Approaches Already Exist
You might think “Is something like that really possible?” But actually, even in today’s VR industry, camera-based inside-out tracking has been evolving, and technologies that don’t require body-mounted devices are steadily increasing.
Quest 3’s AI-based body tracking, SlimeVR’s virtual trackers, pose estimation via smartphone apps. These technologies are already reaching practical levels. If wireless methods like CPD sensors join the mix, the range of options will only expand further.
But Standard Installation in Passenger Cars Is Still Down the Road
So why aren’t CPD sensors standard equipment in domestic passenger cars yet?
Mandatory adoption has already started for transport buses. As mentioned in AISIN’s article, the Ministry of Land, Infrastructure, Transport and Tourism has already issued certification, and it’s in operational use. But standard installation in passenger cars is one step further down the line.
The reason is probably straightforward. The hurdles for practical implementation are higher for passenger cars.
Potential Challenges
Even just from what I can imagine, there are challenges like these:
- False detections: Detecting people outside the vehicle, or conversely, missing a child who’s actually inside
- Radio interference: Mutual interference with other electronic devices
- Cost: The manufacturing unit price hurdle for standard installation in every vehicle
- Regulations: Privacy and radio wave regulations haven’t caught up
- Precision: The maturity of technology to reliably capture subtle biological responses
Each of these needs to be cleared one by one before “standard installation” in passenger cars can be achieved. Automakers also need to be cautious, including questions of responsibility when malfunctions occur.
So right now, the transport bus sector is leading the way, and passenger cars are a bit further out.
But It’s Coming in the Not-Too-Distant Future
That said, my sense is that CPD sensors being widely adopted in passenger cars isn’t too far away.
According to AISIN’s article, standard installation is expected to begin imminently in the United States and Europe, and Japan is expected to follow suit. Technologies driven by strong societal demand attract concentrated investment. Companies have high motivation to develop, and government backing can be expected. Once a breakthrough happens, it’s the type of technology that spreads rapidly.
I predict that within a few years, the phrase “CPD sensor standard equipment” will be a routine entry in new car catalogs.
What Happens to Full-Body Tracking Once CPD Matures?
Let me talk a bit about the further future.
Once CPD sensors, or technology based on the same principle for wirelessly detecting the human body, mature sufficiently — what will happen to the full-body tracking industry?
1. Automation of Full-Body Tracking
First, the automation of full-body tracking will advance.
Full-body tracking today, honestly, requires a lot of preparation. Attaching trackers, powering them on, pairing, calibrating, adjusting base stations. There’s so much to do that it’s not something you can casually jump into.
But if full-body tracking could start with just a single sensor in the room, you could skip all of that. Boot up your PC, launch VRChat, auto-detect full-body tracking. With that flow, you’d enter your avatar in full-body tracking mode with zero preparation.
This would be a change that dramatically lowers the barrier to full-body tracking.
2. The Hardware-Less Era
Next, an era will come where you won’t need the hardware itself.
No need to buy trackers, no need to change batteries, no discomfort from wearing them. This means having the option of “not buying” anything, which is a pure positive for users.
Of course, for professionals and high-end users, precision-focused solutions like base station systems will persist as before. But for the casual crowd who just wants to “try full-body tracking a bit,” being hardware-less will become a perfectly sufficient option.
3. Structural Changes Across the Industry
And this is the biggest story of all — the entire structure of the full-body tracking industry could change.
Currently, the full-body tracking industry is lined with hardware-centric companies: tracker manufacturers, base station makers, IMU chip manufacturers, software vendors. But if hardware-less becomes mainstream, software and signal processing technology will take the lead.
Technology from automotive parts manufacturers — companies that originally have nothing to do with VR — could flow into the full-body tracking industry. These kinds of cross-industry intersections could happen. Personally, I find these industry crossroads pretty exciting.
But Please Don’t Throw Away Your Current Trackers
I’ve been talking about the future, but let me make something clear.
“Well then, I’ll just skip buying trackers and wait for the hardware-less era.”
I’d advise against that.
You Need to Enjoy the “Now”
Hardware-less full-body tracking won’t be realized for at least several years at the earliest. Putting off all the time you could be playing in VRChat until then is far too wasteful.
Besides, just because hardware-less full-body tracking arrives doesn’t mean existing tracker systems will become completely obsolete. In terms of precision and freedom, base station systems will remain strong. Both options should coexist going forward.
If you have the desire to do full-body tracking right now, starting with current equipment is the best move. Rather than waiting for the future, enjoy the present.
Para cerrar
Today I wrote about the future of full-body tracking from a somewhat unusual angle.
Technology development that began from the tragedy of kindergarten bus accidents might come full circle to shape the future of full-body tracking. It’s a coincidence, but technology often evolves from unexpected places like this.
What I value most is “keeping an eye on the possibilities of technology.” You won’t see the big industry trends if you’re only playing inside VRChat. But when you stay aware of technological innovations happening in the outside world, the future of your hobby becomes even more exciting.
The day CPD sensors become standard in cars and their application makes hardware-less full-body tracking a reality — when that day comes, I want to be the first one to review it. Looking forward to that day, I’ll keep playing VRChat with my base stations and VIVE trackers strapped on.
Bueno, eso es todo por hoy.
I’d be happy if I got you a little excited about the future of technology.
Les habla Hiro.
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Reference article:
AISIN “Protecting Tomorrow’s Smiles with a Child Vehicle Presence Detection System.”
https://www.aisin.com/jp/aithink/innovation/blog/005653.html
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