In the modern world of technology, the term “lidar” is heard more and more often, overgrown with myths and guesses. Many car enthusiasts and geeks come across this word in the news about self-driving cars or in reviews of flagship smartphones, but few accurately understand the physical essence of the process. Laser radar, or LiDAR (Light Detection and Ranging), is an active sensor that measures the distance to objects using light pulses. This is not just a camera, but a complex measuring device that creates an accurate three-dimensional map of the surrounding space in real time.
What exactly is lidar for and why are engineers willing to pay huge amounts of money for its installation? The main task of the device is to obtain high-precision data on the geometry of the medium. Unlike regular photography, where we see a flat image, optical rangefinder builds a so-called “point cloud”, where each point has its own coordinates in three-dimensional space. This allows the control system not only to “see” the obstacle, but also to know exactly at what distance it is located, what its shape is and the speed of movement.
In the automotive industry, this sensor is becoming a key element for autonomous driving systems at L3 level and above. However, its use has long gone beyond the automotive industry. Laser scanning It is actively used in geodesy, archaeology, meteorology and even in consumer electronics to improve the quality of photographs. Understanding how this technology works will help us better navigate a future where machines communicate with each other without human intervention.
Physics: How Laser Scanning Works
The lidar operating principle is based on the time of flight of a light pulse (Time of Flight, ToF). The device emits a short laser beam that bounces off an object and returns back to the receiver. Since the speed of light is a constant and known quantity, the microprocessor calculates the distance to the object with millimeter accuracy. This process is repeated millions of times per second, allowing for instant updates. 3D environment map.
The key element here is the laser. Depending on the type of device, this could be an infrared laser with a wavelength of 905 nm or the more advanced 1550 nm, which is easier on the eyes and can cut through rain and fog. Photodetectors capture the reflected signal, and complex filtering algorithms discard noise and false positives, leaving only useful data about real objects.
Why laser?
The laser beam has a very low divergence, which allows for high angular resolution. Unlike radar radio waves, the light wavelength is much shorter, making it possible to distinguish fine details of objects and their texture, although it suffers from heavy precipitation.
It is important to understand that lidar does not see “color” or “texture” in the usual sense, it sees relief and distance. This is why lidar data is often combined with camera and radar readings into a single sensor system. This approach, called sensory fusion, allows you to compensate for the weaknesses of each individual sensor and create a reliable model of the world for decision making.
The role of lidar in autonomous driving of cars
In the automotive context, lidar is often referred to as the “eyes” of a drone. Why is it needed in the car? First of all, to build a dynamic map of the road situation. While cameras can go blind from bright sun or fog up, and radars have low angular resolution, laser scanner ensures stable and accurate positioning of the vehicle relative to the lane and curbs.
Modern ADAS (Advanced Driver Assistance Systems) systems use lidars to implement emergency braking, adaptive cruise control and lane keeping functions. For example, if the car in front brakes sharply, the lidar instantly detects the reduction in distance and transmits a signal to the brake control unit. This happens faster than a person can react.
However, technology implementation faces a number of challenges. The cost of sensors is still high, although it is decreasing every year. In addition, there is the problem of lidars “exposing” each other in a dense stream of cars equipped with such systems. Engineers solve this by encoding the signals and using different wavelengths. Solid state lidars (Solid-State) have no rotating parts, making them more reliable and cheaper to manufacture, paving the way for mass adoption.
Applications in smartphones and consumer electronics
For a long time, lidars were the province of industrial equipment and the military, but the miniaturization of components has made it possible to introduce them into pocket gadgets. Smartphones such as the iPhone Pro series and iPad Pro tablets have a compact ToF sensor. Its main purpose is to improve the camera's focusing performance when shooting in low light conditions and to create a depth of field effect (bokeh) for portrait mode.
In addition to photography, lidar in a smartphone opens up opportunities for augmented reality (AR). Applications can instantly scan a room, determine the size of furniture, or try on virtual objects, “tying” them to the floor and walls with high precision. This is revolutionizing online shopping and interior design by allowing the user to see how a new sofa will fit into their living room before purchasing.
- 📱 Instant camera focusing even in complete darkness.
- 🏠 Accurate 3D room scanning for augmented reality applications.
- 📏Measuring distances to objects using the built-in tape measure application.
- 🎮 Improved gaming experience in AR games with real world interaction.
Game and software developers get their hands on a powerful tool for interacting with the physical world. The laser rangefinder in your phone allows you to create digital twins of real objects. This area is actively developing, and in the future we will see even more applications that use spatial data to navigate inside buildings or find lost items.
Comparison of Lidar, Radar and Camera: What's the Difference?
To understand the value of lidar, it is necessary to compare it with other common sensors. Cameras, radars and lidars are the three pillars on which the perception system of any modern robot or smart car is built. Each of them has its own strengths and weaknesses, and the ideal sensor “for all occasions” does not yet exist.
| Characteristics | Camera (Video) | Radar (Radio) | Lidar (Laser) |
|---|---|---|---|
| Operating principle | Optical sensor (light) | Radio waves | Laser beam (light) |
| Distance accuracy | Low (requires computation) | High | Very high (mm) |
| Working in the dark | Bad (needs light) | Excellent | Excellent |
| Weather influence | Goes blind in fog/rain | Breaks through the rain/fog | Reduced range in heavy rain |
| Speed detection | Only by personnel (indirectly) | Direct (Doppler effect) | Only by position change |
The cameras provide rich texture and color information, which is necessary for recognizing road signs and traffic lights, but they are useless at night without illumination and do not judge distance well. Radars can “see” through the rain perfectly and accurately measure speed, but their resolution is so low that they cannot distinguish a person from a pole. Laser scanning fills this niche by providing precise geometry but suffers from heavy rainfall.
This is why modern systems use a combination of all three types of sensors. Sensory fusion allows you to combine data: the camera says “this is a red light,” the radar shouts “the object is quickly approaching,” and the lidar clarifies “the obstacle is exactly 15.4 meters away.” Only the totality of this data allows artificial intelligence to make safe decisions.
☑️ Criteria for selecting a sensor for a project
Types of lidars: mechanical, solid-state and hybrid
Technologies do not stand still, and the design of lidars is undergoing significant changes. The first prototypes we saw on the roofs of Google's test drones were bulky "buckets" spinning at high speeds. These were mechanical lidars, which provided a 360-degree view, but had a limited resource due to the presence of moving parts and high cost.
Today the industry is moving towards Solid-State solutions. Such devices do not have rotating motors; the beam is controlled electronically using micromirrors (MEMS) or phased arrays (OPA). This makes them compact, cheap to mass produce and resistant to vibration. They can be built directly into a car bumper or smartphone body, which was impossible with mechanics.
⚠️ Warning: Solid state lidars often have a limited field of view (FOV) compared to mechanical ones. To obtain a complete all-round view in a car, it may be necessary to install several of these sensors around the perimeter of the body.
There are also hybrid solutions and rotating mirror lidars (MEMS), which fall in between. They are more compact than purely mechanical ones, but more mobile than completely static ones. The choice of device type depends on the task: for mapping the terrain, a wide view is needed, and for an emergency braking system, a narrow but fast beam directed forward is sufficient.
Prospects for development and limitations of technology
Despite the obvious advantages, the technology has its limitations. The main problem is weather conditions. Heavy snow, thick fog, or heavy rain can scatter the laser beam, creating “noise” in the image or reducing range. Engineers are combating this by using 1550 nm lasers, which are less prone to scattering, and by developing algorithms that can “see” through the noise.
Another aspect is cost. Although prices are falling, high-quality long-range lidars are still expensive. However, Moore's Law and the development of production processes in China and the USA are gradually making this technology accessible even to mid-range cars. In the future, we will reach the point where lidar will become the same safety standard as ABS or airbags.
When choosing a car with driver assistance systems, pay attention to the presence of lidar in the equipment description. Its presence often indicates a higher level of autonomy (L3+) than just a set of cameras and radars.
Prospects for the development of the industry are also associated with a reduction in size and energy consumption. Quantum lidars and new types of sensors promise even greater accuracy and range. This will open the door not only to driverless taxis, but also to smart cities, where the infrastructure itself will monitor traffic and pedestrians, preventing accidents before they occur.
⚠️ Warning: Lidar emits laser light. Although modern devices are certified as eye safe (Class 1), it is not recommended to specifically look into the emission hole of a working industrial scanner at close range.
Practical application: where else is lidar used?
Beyond roads and smartphones, lidars have found widespread use in science and industry. Archaeologists are using airborne lidars (mounted on drones or airplanes) to search for ancient settlements under the dense forests of the Amazon or Cambodia. The laser beam penetrates the treetops and builds a map of the earth's relief, revealing hidden structures invisible from the ground.
In construction and BIM modeling, handheld scanners make it possible to create accurate digital copies of buildings for renovation. Robot vacuum cleaners use simplified versions of lidar sensors (LDS) to navigate around the apartment, building a map of the room without crashing into the legs of chairs. Even in meteorology, lidars help measure the concentration of aerosols and clouds in the atmosphere.
- 🏗️ Monitoring deformations of bridges and buildings in real time.
- 🌲 Forest monitoring and biomass assessment.
- 🤖 Navigation of warehouse robots and forklifts.
- 🛰️ Docking of spacecraft and satellites.
Thus, the answer to the question “what is lidar for” covers almost all areas of human activity where accurate measurement of space is required. From helping you park your car to mapping Mars, this technology has become an integral part of technological advancement.
Lidar is not just a distance sensor, but a fundamental tool for digitalizing the physical world, allowing machines to “understand” the geometry of space as well as humans.
Frequently asked questions (FAQ)
Can lidar work in heavy rain or snow?
The effectiveness of lidar decreases during heavy precipitation. Raindrops and snowflakes reflect the laser beam, creating “noise” and reducing the detection range of objects. However, modern filtering algorithms and the use of longer waves (1550 nm) make it possible to partially compensate for this effect, maintaining the functionality of the system.
Is lidar dangerous for the eyes of humans and animals?
Certified civilian lidars (laser safety class 1) are absolutely safe for the eyes, even when directly hit by the beam. The radiation power in them is strictly limited. However, industrial or military designs can be dangerous, so you should not look into the emitter of unknown devices.
What is the main difference between lidar and conventional radar in a car?
The main difference is the accuracy of the image construction. Radar measures speed and distance well, but “sees” objects blurry. Lidar builds a detailed 3D map with millimeter precision, allowing you to distinguish the shape of an object (for example, distinguishing a cyclist from a pedestrian), but it works worse in fog.
Why does Elon Musk say that lidars are not needed?
Elon Musk and Tesla are relying on “pure vision” (computer vision) using cameras and neural networks, believing that the human brain can do without lidar, which means AI can too. Most other manufacturers (Waymo, Mercedes, BMW) consider lidar a mandatory backup channel for safety information.
How much does it cost to install lidar on a regular car?
Currently, factory-installed lidar is available in premium configurations or as an option for several thousand dollars. For self-installation (post-market), ready-made solutions are rare and expensive, as they require integration with on-board vehicle control systems.