Will the car lidar hurt your eyes?

The mobile phone camera shoots the car lidar, and the sensor is directly burned out of the green line.

In a recently circulated video, the screen began to appear abnormal after approaching the lidar on the roof of the NIO ES7, and finally left two straight lines on the screen, one horizontal and one vertical.

This is typical of a camera's CMOS sensor being burned out by a laser.

At present, it is nothing new to put lidar on the car, and car companies are also willing to use lidar as the core selling point in the field of assisted driving. There is even more than one lidar on "new force" models such as Xiaopeng and Jihu.

Although you haven't noticed it, the oncoming car may be "scanning" at you with lidar.

This also leads to a more important question:

Does vehicle-mounted lidar affect the human eye?

After all, if the CMOS is broken, it can be replaced, and our eyes are only this pair.

LiDAR, what am I looking at you for?

Let’s start with the flow-saving conclusion: Under normal circumstances, the vehicle-mounted lidar will not be harmful to the human eye.

The International Electrotechnical Commission standard (IEC 60825-1) divides laser products into seven classes:

Class 1, Class 1M, Class 2, Class 2M, Class 3R, Class 3B, Class 4

A larger number means higher power, which also means that it is more likely to damage the human eye.

Class 1 laser refers to "under any conditions, the eyes will not be exposed to harmful optical radiation" , while class 3 laser and above will cause damage to the eyes when looking directly at the laser beam, class 4 laser can be used for cutting, etc. Mechanical processing, careless use can cause fire.

There are many kinds of common laser products, in addition to vehicle lidar, there are also such as:

• LiDAR on iPhone
• Household appliances such as sweepers
• The laser range finder used by the construction team can be seen on the road
• laser weapon (no)

Laser products have already covered our daily life, and it is not uncommon to be irradiated by laser. The laser products listed above are Class 1 laser products except for laser range finders and laser weapons.

The vehicle-mounted lidar that is already on the car also belongs to the category of Class 1 lasers . Whether it is the Tudatong Falcon selected by Weilai or the Hesai AT128 ideally selected, they are all in this category-this also means that you can rest assured Go out without worrying about what will happen to your precious eyes.

However, different vehicle-mounted lidars still have different bands, and different bands have different effects on the human eye.

At present, the common vehicle lidar is divided into two bands of 905nm and 1550nm.

The 1550nm band is farther away from the visible light spectrum. At the same time, most of the light will be absorbed by the lens and cornea of ​​the eyeball before reaching the retina. The existence of this high safety threshold allows car companies to further increase the power in order to obtain better recognition results.

The laser in the 905nm band is closer to the visible light spectrum and is not easily absorbed. The laser will focus on the retina. Affected by this, the lidar in the 905nm band has stricter power restrictions to meet the requirements of human eye safety.

Of course, talking about toxicity regardless of dosage is nonsense. As long as it meets the standard low power conditions, whether it is 905nm or 1550nm, it is safe enough for human eyes, and it is almost impossible to cause any substantial damage to human eyes.

After all, car companies are not stupid. If it is obviously harmful to the human body, not to mention that it is contrary to the "safety" purpose of LiDAR on the car. The social responsibility and public opinion pressure it bears will discourage car companies, let alone large The scale is assembled.

Protect our camera

Rest assured, staring at a "car with horns" won't burn your eyes out as long as the lidar is still in laser class 1 range.

But CMOS of all kinds of lenses don't think so.

If you search the Internet for CMOS cases damaged by lasers, related tragedies abound. There are also the following warnings in the help guide on Sony's official website:

Do not expose the lens directly to light beams such as laser beams. Doing so can damage the image sensor, resulting in a malfunction.

The CMOS sensor is more sensitive to the wavelength of light, or in other words, "it's too strong", allowing it to see "things it shouldn't see". Unlike the human eye, CMOS does not have the ability to absorb laser light, which also makes CMOS more likely to be damaged by high-energy lasers.

In the initial case, the camera is facing a Weilai ES7, and the roof is a 1550nm band Tuda Falcon lidar. 1550nm lidars are typically more powerful and more likely to “attack” nearby cameras. In the end, CMOS was scarred by the struggle, leaving an indelible and permanent mark.

However, we might as well imagine a little bit. Since the on-board lidar has the possibility of burning out the camera, if it "accidentally" illuminates the surveillance camera on the road, wouldn't it be…

If you want to turn your car into a mobile electronic warfare weapon and fight against the CMOS on the road, you need:

1. The distance should be close enough for the CMOS to receive enough energy;
2. There can be no occlusion of various objects.

Looking at it this way, the conditions for the roof-mounted lidar to burn out the camera are relatively harsh. On the other hand, the monitoring cameras on the road are usually far away, and the probability of being burned out by the lidar is very low. Friends who rely on the on-board lidar and monitoring cameras are hard-headed, and obey the traffic rules honestly.

However, not all vehicle-mounted lidars adopt a watchtower layout and are placed on the roof of the vehicle, and not all cameras are far away.

Xiaopeng is used to installing the lidar at both ends of the front of the car, at the lower edge of the headlights, and there is indeed the possibility of close contact with the barrier camera that reads the license plate.

At present, there are no large-scale reports, but if the camera is often burned by the laser, I believe that the stakeholders will have fried the pot long ago.

But under special conditions, lidar does have the possibility of damaging the CMOS camera, although this possibility is small.

The next time you want to take pictures of lidar details, it is best to pay attention to the startup status of the vehicle, so as not to "eclipse" CMOS if the car cannot be taken.

LiDAR, should I choose it? How to choose?

Back to lidar itself.

905nm and 1550nm, these two wavelengths of vehicle lidar are currently the most common choices. But how to choose between the two is a good question for both car companies and consumers.

Basically, it's an arithmetic problem about money.

As mentioned above, because it is farther away from the visible light spectrum, the laser radar with a wavelength of 1550nm is safer for the human eye, and the power can be increased higher. Fog performance is also better, resulting in more enriched information.

The amount of information directly determines whether the assisted driving system can make a correct judgment in the end.

All in all, the ceiling is higher.

But just like the "golden sentence" of a certain car brand's advertisement: "good" has a high probability of being "expensive".

Restricted by the semiconductor process, the current 1550nm lidar uses fiber lasers and has higher requirements for the receiver. The cost is higher than that of 905nm, and the increase in cost will eventually be reflected in the price. The real laser radar The "rich brother" who pays the bill is still the car owners of the terminal.

In contrast, 905nm is not useless.

Cheaper is of course one of the great qualities of 905nm lidar. In addition, because the power is lower than that of 1550nm, the operating temperature and energy consumption of 905nm are better.

This also allows 905nm lidar to have greater sinking potential in the market, and has the opportunity to spread to more models.

In addition, the "body" of the 905nm lidar is also smaller, so it has a better chance to be perfectly integrated into the body design, avoiding the abrupt design of "horns on the head".

Although Musk resolutely distances himself from the assisted driving of the lidar route, and Tesla's pure visual assisted driving does not have a place for lidar, at least for now, lidar is still a selling point vigorously promoted by many car companies. The reason is also very simple: multi-sensor fusion brings more security redundancy.

A purely visual route means that the assisted driving system needs to judge all information through the camera and perceive objects through algorithms, which will lead to two problems:

The first is not being able to see clearly, and the second is not knowing.

Pure vision means that assisted driving is affected by road lighting conditions and weather conditions just like the human eye. In the case of poor light conditions on the road surface, the difficulty of judgment suddenly rises.

The lidar is not affected by lighting. For night driving, the addition of lidar is tantamount to an extra layer of protection (this may also explain why Tesla's headlights are usually higher than other brands).

Even when you can see clearly, pure vision still relies on machine learning to recognize objects. For undefined, static alien objects, pure vision algorithms may also ignore them.

The fusion of multiple sensors provides more perception means for assisted driving at the hardware level. In theory, the upper limit of perception is naturally higher.

Unless Tesla is as obsessed with and accumulated purely visual routes, more and more sensors and radars will be installed on the road, and the reason is probably only two words: "safety".

Not just to your eyes, but to everyone involved in the traffic.

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