Hello everyone, my name is Teppei of KOYO Orient JAPAN's Product Division.
I have some exciting news for everybody! I recently learned that the new iPad Pro will be equipped with LiDAR scanner! This will be the first optimized LiDAR device for Augmented Reality applications, for most people. Explosive development of LiDAR applications is expected. We expect the iPhone 12 to come equipped with LiDAR as well. This is incredible!
For those of you who are not familiar with LiDAR, don't worry because in this blog we'll be going over what LiDAR is and its applications.
LiDAR and Automatic Driving
In recent years, the automobile industry has reached a major turning point. Electric Vehicles you may ask? Yes, that is true, but the development of sensor technology has opened a way to achieve humanity’s dream of automatic driving.
One of the technologies that holds the key to achieving this dream is called “LiDAR.”
LiDAR stands for "Light Imaging Detection and Ranging". The L in “LiDAR” may also stand for Laser. The literal Japanese translation is "Detection and Ranging by Light." There have been proposals for the translation to be "Ranging Sensor".
In general distance measurement mechanisms, lasers are often used. When using a laser, a laser beam is radiated instantaneously, and if the laser beam hits an object, the light that hit the object returns and is received by the mechanism. In some cases, the distance to the target can be determined in no time using this mechanism. A laser rangefinder for golf is a good example for this.
LiDAR applies this and creates Point Cloud Data by repeating many observations in 2D or 3D in a short time. This makes it possible to grasp the shape of the space and the existence of the object. You will find it to be a very useful device for automatic driving.
Now that we understand the basic mechanism of LiDAR, what kind of performance is important for it to be utilized in automatic driving? For example, if the distance between the observation points is too wide, a narrow obstacle may pass between the lasers and may not be recognized. In order to narrow the interval, the number of measurements made in a set period will become very important.
Observation distancing is an important feature. Considering the braking distance of a car, accurate measurement of at least 100 meters is required.
However, the further the distance, the less light is reflected, and the more difficult it is to detect. Such refined light would be difficult to distinguish in an environment full of extraneous light “noise.”
Therefore, as a countermeasure, there is a method that increases the output of the laser to increase the reflected light, making detection easier.
However, with this method there is a big problem, that is, the damaging effect on the human eye. I’m sure you have all heard of malicious pranks using laser pointers. A strong laser light source that is focused on the fundus of your eye can cause serious damage to it.
The LiDARs currently being used mainstream uses near-infrared wavelength of 900 nm mainly for cost reasons, but this wavelength is close to visible light, so the same eye damaging danger is present (in the case of pulse emission). Therefore, in recent years, LiDAR has switched to using longer near-infrared wavelength of 1500 nm.
By switching to 1500nm the advantage is of course that the damaging effect on the eyes is minimal. Infrared light at 1500nm has an eye power 1 million times greater than visible light (pulse emission). This allows you to use a laser that is safe and sufficiently powerful for your eyes.
The disadvantage of using 1500nm is the price. Since the market is large and inexpensive photo-detectors, made of silicon, do not have sensitivity in the 1500nm range, it is necessary to prepare special ones made of InGaAs (Indium Gallium Arsenide). This material alone is several times more expensive than that of silicon. The price of a silicon LiDAR is said to be 100,000 yen or more. That can seem expensive for it to be installed in ordinary consumer cars. So the question is, how much would a high precision 1500nm LiDAR cost?
This cost and performance improvement of LiDAR is likely to be the key to future automatic driving. It is a field that is actively being studied by renowned large companies and venture companies in several countries, so I believe we will make great progress in the future.
Up until now, iPhones used "Dot Pattern Projection (Active Stereo Method)" to determine the subject's distance from the camera so you may wonder why LiDAR will be used in this new iPad instead. I wondered about it myself. I think that for the active stereo method to work properly, the camera and the projector need to be sufficiently separated, otherwise the measurement accuracy at long distances will be poor. Even if it is most suitable for face recognition applications in the range of 30 to 50 cm, it may not have matched the iPad Pro's measurement range of 5 m this time.
Click here for an introduction video of an application that utilizes LiDAR. It's amazing!
The future looks exciting! I am very excited to what new possibilities LiDAR will unlock!
Well that's it for this blog, I hope you enjoyed. Please feel free to leave comments or questions. Check out our next blog where we go over the world of Far-Infrared here!