1. Does lidar emit radiation?
Does laser damage the human eye? In short, discussing harm without considering laser power is meaningless!
Let's first look at the international regulations regarding the safety of laser equipment. The U.S. Food and Drug Administration (FDA) classifies laser equipment into six categories based on their laser output value: Class I, Class IIa, Class II, Class IIIa, Class IIIb, and Class IV. Class I (power less than 0.4mW) poses no biological hazard and requires no special regulation. Typical applications include laser pointers, CD players, CD-ROM devices, geological exploration equipment, and laboratory analytical instruments. Class IV (power greater than 500mW) emits laser radiation, whether direct or scattered, that is harmful to the skin and eyes. Typical applications include surgery, research, cutting, welding, and micromachining.
The question is, is our lidar safe? The answer is, it's extremely safe!
Our RPLIDAR system uses a low-power infrared laser as the emission source and is driven by a modulated pulse method. The laser emits light in a very short time, fully meeting the Class I laser safety standard and ensuring safety for humans and pets.
Furthermore, RPLIDAR has obtained CE certification from SGS, meaning our products fully comply with EU safety standards and will not endanger the safety of humans or pets. At this point, some may wonder if using LEDs instead of lasers as the light source would be safer. Actually, no, this is determined by the optical characteristics of LEDs.
LEDs, commonly known as light-emitting diodes, are commonly used as light sources in daily life, such as in flashlights, LCD monitors, desk lamps, and car headlights. The LED industry has only existed for a few decades, making it relatively new. There are no clear national regulations or standards for defining LED products, and the industry as a whole lacks relevant supervision and regulations.
Returning to the topic of range sensors, to achieve a certain measurement distance, the brightness of the light source must meet certain requirements, much like a flashlight—the farther it shines, the brighter it needs to be. Lasers, thanks to their high focusing ability, can transmit almost all of the light source's actual power to the target distance. However, LEDs have a large divergence; to achieve the same measurement distance, their light source power may need to be 10 times or even hundreds of times greater than that of lasers.
In other words, to achieve a longer measurement distance, it is undoubtedly necessary to significantly increase the optical power, and LEDs pose a greater potential hazard compared to lasers.
Besides their completely different optical properties, LEDs and lasers also differ greatly in their actual performance. The core advantage of lidar (or photoradar) is its excellent directivity, meaning the sensor can accurately reflect the actual position of the target. For robots to achieve localization and navigation, both a clear map and precise navigation are indispensable, and the "point-and-shoot" characteristic of lasers is key to achieving this. Other technologies (such as LEDs, ultrasound, etc.) cannot meet this requirement.
II. Applications of LiDAR
1. Self-driving cars
Autonomous driving has become increasingly popular in recent years, and LiDAR is arguably the most crucial component in this field. Autonomous vehicles are intelligent cars that use onboard sensing systems to perceive their environment, automatically plan routes, and control the vehicle to reach predetermined destinations. Currently, LiDAR applications encompass various functional modules for autonomous driving, including localization, curb/drivable area detection, lane marking detection, obstacle detection, dynamic object tracking, and obstacle classification and recognition.
2. Robotics
LiDAR (Light Detection and Ranging) is often referred to as the "eyes" of robots. So how do these "eyes" help robots identify objects and directions?
It calculates the relative distance between itself and the target based on the time it takes for the laser to return after encountering an obstacle. The laser beam can accurately measure the relative distance between the edge of an object's outline and the device in the field of view; this outline information forms a point cloud and creates a 3D environment map. For example, Huanchuang Technology's LiDAR has achieved sub-millimeter accuracy, better assisting robots in providing services.
3. Medical applications
A U.S. national laboratory has developed an integrated system that can perform three-dimensional lidar localization and detection of the surface tissues of burn patients to determine the extent of damage. Using the localization results, a laser can automatically remove necrotic tissue to promote new tissue growth. Researchers hope that this continuous-wave lidar mapping system can remove necrotic skin and muscle from patients' bodies.
4. Unmanned aerial vehicles (UAVs)
Airborne lidar is an airborne laser detection and ranging system installed on aircraft, capable of measuring the three-dimensional coordinates of objects on the ground. In the 1970s, NASA began developing airborne laser scanning technology for LiDAR mapping, and its development progressed rapidly, leading to commercialization in the late 20th century.
5. Military applications
China's attack lidar is already quite advanced, incorporating five of the world's most cutting-edge core technologies: breakthroughs in laser materials research, breakthroughs in the physical mechanisms and imaging spectra of laser radiation materials, breakthroughs in one-time rapid tracking and positioning control technology, breakthroughs in high-density energy reversible conversion carrier materials, and breakthroughs in laser imaging technology. In addition, significant achievements have been made in areas such as sea mine detection lidar, chemical reagent detection lidar, atmospheric monitoring lidar, and biological and chemical land warfare lidar.
