Eliminate blind spots and analyze the secrets hidden in the car's side mirrors

    On June 12, a vicious traffic accident caused by a lane change at a highway exit occurred in Hangzhou, resulting in the serious consequence of one death. In addition to remembering the deceased, the cause of the accident also triggered my thinking. Although the exact cause of the accident has not yet been determined, we analyzed the surveillance video footage and found that in this accident, the main cause of the accident was that the car missed the intersection and forced to change lanes, but the driver may not have carefully observed the side mirrors in the process of hasty lane change or misjudged due to the blind spots in the side mirrors, which is another factor in the accident. If in similar situations, the vehicle can warn the driver of the approaching potential danger, perhaps the tragedy will not happen. With the rapid development of automobile technology today, the field of view of the side mirrors is constantly expanding through improved design, and the electronic system integrated in it can further eliminate the blind spots. Today, let's explore what secrets the side mirrors contain to escort our driving safety.

　　● Hard work 1: Expand your horizons

　　The most basic function of the side mirror is to observe the vehicles coming from both sides. The larger the field of view of the side mirror, the higher the safety factor of the driver in driving when merging, overtaking, turning, reversing, etc. The easiest way to achieve this is to enlarge the side mirror. The larger the mirror surface, the better the field of view. However, everything will turn into the opposite when it reaches its extreme. This enlargement is not unlimited. Too large a size will make the whole vehicle look uncoordinated, and it will also affect the driver's observation of the road conditions in front of the side. After repeated design and development, the "rabbit ear side mirror" finally came into being. This side mirror is mainly used on large vehicles and is named because its appearance resembles two rabbit ears. Its wide mirror surface largely solves the problem of narrow field of view of the side mirror. At the same time, its unique shape will not give people a stupid feeling.

　　Although the rabbit-ear side mirrors are unique, they still look a bit abrupt for a family car. I really can't imagine how cute a convertible sports car with two big ears would be, and the impact of oversized side mirrors on the wind resistance of the whole vehicle also makes this approach unfeasible for passenger cars. For example, the side mirrors of super sports cars are often made into slender streamlines to reduce wind resistance, and Volkswagen's Volkswagen XL1 replaces traditional side mirrors with cameras. There is no way. Since it can't be made bigger, we can only work hard in other aspects.

　　We have learned the principle of convex mirrors in junior high school physics class. We often see convex mirrors at the corners of narrow alleys to show us the situation on the other side of the corner. Engineers who are well versed in this will naturally not turn a deaf ear to this. Installing convex mirrors directly on the side rearview mirror is the simplest innovation in its application, which solves the problem of insufficient field of view of the side rearview mirror. However, this method is not very beautiful. There is an extra piece on the side rearview mirror out of thin air, which always gives people a feeling of coping. Therefore, many manufacturers have a relatively complex design - a hyperbolic side rearview mirror.

　　The curvature of the side mirror will change, with the curvature of the mirror on the outside of the vehicle larger to expand the field of view of the side mirror. Of course, the larger curvature will cause visual distortion, so for safety reasons, manufacturers will mark lines on the mirror surface to remind drivers to pay attention to distortion. (If you want to have a more intuitive understanding of the impact of the side mirror design on the field of view, please read "Reference to knowledge that driving schools don't teach (1) Using the outside mirror to judge the distance between vehicles", which contains actual test content)

　　● Hard work 2: Heated side mirrors

　　Through the improvement of the mirror surface, the problem of insufficient vision of the side rearview mirror has been greatly improved. However, the visibility of driving in rainy days is much worse than that in sunny weather. The raindrops falling from the sky form a water curtain in the air, which affects the driver's vision. In this environment, you always have to be alert when driving, and you can't be careless. When the vehicle needs to turn or merge, you need to be careful to avoid accidents. But when your eyes are focused on the side rearview mirror, you painfully find that the side rearview mirror is covered with water droplets and becomes blurred, like a mosaic. What should you do at this time? I believe many people have encountered such a thing. In this case, there are often only two choices, either to open your eyes and take a closer look; or to wrong yourself. In order to wipe off the water droplets on the side rearview mirror, you can only roll down the window and let the cold icy rain hit it randomly.

　　The side mirror heating function is developed to avoid the above situation. Its working principle is very simple. Just install an electric heater (electric heating film) in the lens of the side mirror. At this time, if you encounter rainy and snowy weather again, just press the side mirror heating button, and the electric heater will quickly heat the side mirror surface to a fixed temperature (usually between 35-60 degrees Celsius) within a few minutes, and use the heat of the electric heater to evaporate the water on the side mirror, so as to avoid the trouble caused by unclear vision.

　　● Hard work three: Anti-glare

　　For drivers, it is not always necessary to see as clearly as possible. Anyone who has driven at night knows that the lights of the car behind are particularly dazzling in the dark night, which will affect the driver's vision. The side mirror with anti-glare function can filter out some of the strong light to ensure the driving safety of the vehicle.

　　The most commonly used anti-glare method at present is to coat the surface of the side mirror with a coating to filter strong light. Although chrome-plated side mirrors can effectively prevent glare from strong light, the reflectivity of this coating is low, and the night vision will be slightly dim. Therefore, we more often use blue mirrors coated with titanium dioxide and silicon dioxide. This side mirror can interfere with high-wavelength visible light that is easy to cause glare and convert it into blue light, which is the light that human eyes can adapt to the most, thereby achieving an anti-glare effect. However, the processing technology of this side mirror is complicated and the cost is high, so it is often used in mid-to-high-end cars.

　　In addition to adding a coating to the surface of the side mirror, some electrochemical side mirrors also have an anti-glare function, such as the EC electrochemical side mirror. It contains a kind of adhesive inside, which will darken as long as a small charge is applied to it. Therefore, when the headlights of the rear vehicle emit strong light, the light sensor of the side mirror will sense the light intensity and stimulate the charge of the mirror, so that the side mirror will no longer be dazzling.

　　summary:

　　As an important guarantee for driving safety, the side mirrors have been painstakingly improved in terms of their own functions. They should enable the driver to see clearly and widely, and avoid the impact of excessive light on the driving safety of the vehicle. But today, when electronic technology is widely used, can only internal changes meet people's stringent requirements for driving safety? Obviously, this is far from enough. Due to the limitations of the body structure, blind spots are still unavoidable, which poses a hidden danger to driving safety. With the assistance of electronic systems, a two-pronged approach can achieve a more intuitive and convenient understanding of every corner outside the car, and some components of these systems are also cleverly installed in the side mirrors.

　● Practice external skills 1: Lane-changing assistance system

　　During driving, due to the design of the vehicle body, there are always some blind spots in the visual range that the side mirrors can provide us. In order to solve this problem, many vehicles are equipped with a lane change assistance system. The warning indicator of this system is installed on or around the side mirrors, which can provide assistance to the driver on the basis of the side mirrors. This system can detect the rear vehicle through radar, and remind the driver of the possible risk of lane change through warning lights, reduce the hidden dangers of blind spots to vehicle lane change, and improve the safety factor of driving. This system is widely used by major automobile manufacturers. The implementation methods are basically the same, but there are certain differences in detection methods, ranges, installation arrangements, etc.

　　◆ Audi side assist system

　　Domestic configuration models:

　　The manufacturer calls the lane-changing assistance system used in the domestic Audi A4L, A6L and other high-configuration models the Audi Side Assist system. It assists the driver to eliminate blind spots and complete lane changes through two radars installed on both sides of the rear bumper and indicator lights installed on the inside of the side mirrors. The system can identify the current position, speed and direction of movement of the vehicle behind. Its working principle is to first generate high-frequency electromagnetic rays, namely "microwaves", and then receive and analyze the rays returned by the detected object. The reflection characteristics of objects vary. Metals can reflect rays well while plastics can almost completely penetrate rays, so the system can detect motor vehicles very accurately.

　　When the vehicle speed exceeds 60km/h, the system starts to monitor the road conditions within 50m behind and to the side of the vehicle. If there is a potential risk of changing lanes, the warning indicator on the side mirror in the corresponding direction will light up. If the driver still turns on the turn signal and tries to change lanes, the warning indicator on the side mirror will increase in brightness and start flashing to remind the driver of the danger.

　　◆ One of Buick's IntelliSafe proactive safety system features

　　Domestic configuration models:

　　GM Buick's IntelliSafe forward-looking active safety system consists of an adaptive cruise control system, a collision warning system, a lane departure warning system, a lane change assistance system, and a parking warning system. Multiple ultrasonic sensors and cameras installed in the front and rear of the vehicle can monitor the entire vehicle in real time, alerting the driver to take effective evasive measures in the first place, thus reducing the probability of safety accidents.

　　As an important part of IntelliSafe, the lane change assist function is implemented in the same way as the Audi side assist system. When a vehicle approaches, the system warns the driver through the orange light in the exterior mirror, reminding the driver not to change lanes. When a vehicle is within 3 meters behind the rearview mirror blind spot, the system will again warn through the orange light alarm in the exterior mirror, but its detection range is larger than that of the Audi side assist system, up to 70 meters.

　　◆ Volvo BLIS blind spot information system

　　Domestic configuration models:

　　Volvo's BLIS blind spot information system is different from the lane change assistance system used by Audi and Buick. It uses the built-in cameras under the rearview mirrors on both sides to feed back the rear blind spot image to the display screen of the on-board computer, and a warning indicator light is installed on the rearview mirror pillar to remind the driver to pay attention to the blind spot in this direction.

　　The camera will monitor a sector-shaped blind spot at a distance of 3 meters wide and 9.5 meters long at 25 frames per second. If a moving object (vehicle or pedestrian) with a speed greater than 10 kilometers per hour and a speed difference of 20-70 kilometers per hour from the vehicle itself enters the blind spot, the system will compare each frame of the image. When the system thinks that the target is getting closer, the warning light on the A-pillar will light up to prevent accidents. However, due to the use of cameras to collect information, when visibility is extremely poor (such as heavy fog or blizzards), the working state may be affected to a certain extent, but the BLIS system will also give corresponding prompts to the driver at this time. This system has been first used in models such as XC70, V70 and S60 since 2005, and since then all Volvo models have adopted this system.

　　● Practice the second external skill: Lane departure warning system

　　Domestic configuration models:

　　We have introduced the lane departure warning system in detail in "The Third Eye Analyzes the Secrets Behind the Central Rearview Mirror". It generally uses a single-lens camera installed on the central rearview mirror to scan the road ahead, and warns or corrects when the vehicle deviates from the lane to ensure the vehicle's driving safety. However, not all lane departure warning cameras are installed in the central rearview mirror, and Dongfeng Nissan X-Trail is an exception.

　　The lane departure warning system of Dongfeng Nissan X-Trail does not install the camera on the central rearview mirror, but is installed under the side rearview mirror. When the vehicle is driving, the camera under the side rearview mirror scans the lane lines on both sides of the vehicle body to determine whether the vehicle has deviated from the lane. The advantage of this design is that it can be integrated with the all-round vehicle body image, adding another solution to the layout of the lane keeping system.

　● Practice external skills three: electronic body image

　　Electronic body imaging system is probably familiar to everyone. Many models nowadays have this function. This system can achieve 360-degree all-round without blind spots. Through the in-car display screen, the environment around the car body can be seen at a glance, which greatly increases the driving safety in parking and reversing situations. The side monitoring camera is installed on the side rearview mirror.

　　The most representative one is the all-round vehicle body imaging system. The system mainly consists of the following six parts: image acquisition, camera calibration, image transformation, image beautification, image seamless splicing and fusion, and image display. Image acquisition often uses four super-wide-angle cameras SWVC (Super-Wide-View-Camera) installed on the front, back, left, and right sides of the vehicle body to capture the surrounding conditions of the vehicle. However, since the image will produce "fisheye distortion" after using SWVC, it is necessary to synthesize and correct the image through calculation processing to synthesize a panoramic bird's-eye view around the vehicle body, so as to display the real image around the vehicle on the on-board display screen to avoid the risk of collision during driving.

　　◆ Nissan and Infiniti AVM all-round vehicle imaging system

　　Configuration model:

　　Nissan's X-Trail, Qashqai and other models, as well as its high-end brand Infiniti's JX, QX series and many other models are equipped with AVM all-round body imaging system. The system uses four cameras at the front of the vehicle, the side mirrors and the rear of the vehicle to monitor the surrounding environment of the vehicle without blind spots. The real-time images taken by the four cameras in different directions are processed and spliced ​​and displayed on the display screen in the cab.

　　The biggest advantage of this system is that the driver can see the situation around the vehicle at a glance when maneuvering the vehicle at low speed, which is more convenient when maneuvering and parking. The larger the car, the more obvious the advantage of this function. Similar to this is Volkswagen's AreaView all-round body imaging system.

　　◆ Honda Accord Lane Watch

　　Domestic configuration models:

　　Although models such as the ninth-generation Accord of GAC Honda do not have all-round body images, the Lane Watch side monitoring function they are equipped with can also eliminate blind spots on a large scale and reduce safety hazards. This function can assist the driver in reversing when the vehicle is reversing, which is what we usually call reversing images. However, the difference between it and the general reversing image system is that in addition to the reversing camera installed at the rear of the vehicle, a camera is also installed under the right rearview mirror of the vehicle to monitor the blind spot on the right side of the vehicle. The driver turns it on by turning on the right turn signal or pressing the button on the top of the steering lever. Although its field of view is not as powerful as the all-round body impact system, it has better clarity and can avoid safety hazards caused by the blind spot on the right side of the vehicle.

　　● Practice External Skill 4: Terrain Monitoring System

　　Terrain monitoring systems are often found in high-end SUV models. Since these models often drive in various difficult environments, major automobile manufacturers will preset some driving modes to ensure the vehicle's maneuverability under these special road conditions. The role of the terrain monitoring system is to feedback the road conditions to the driver through the camera, eliminate blind spots during driving and assist the driver in better selecting the vehicle driving mode.

　　◆ Toyota MTM multi-terrain selection function monitoring system

　　Domestic configuration models:

　　The MTM multi-terrain selection function monitoring system used by FAW Toyota Prado VX series models is a type of terrain monitoring system. The system allows the driver to clearly know the position of his vehicle and the road conditions through the cameras located at the front, rear, and both side mirrors and the front wheel steering angle prompt in the middle of the instrument panel. When passing through complex roads, it can tell the driver when and how to turn the direction, and assist the driver to choose the most appropriate driving mode, so that the vehicle always maintains the best driving state.

　　When the MTM system is in operation, the four cameras distributed in the front, back, left and right of the vehicle can also help the driver monitor the situation around the vehicle and eliminate the driver's visual blind spots. When many off-road vehicles are climbing steep slopes with large angles, the driver can only see the blue sky and white clouds in front of them. At this time, the camera in front of the vehicle can timely present the road situation in front of the vehicle to the driver on the display screen, which obstacles should be avoided and the distance to the top of the slope will be clear at a glance. At present, SUV models such as FAW Toyota Prado are equipped with this system.

　　◆ Land Rover wading sensing function

　　Configuration model:

　　Range Rover Sport and other models can be equipped with a wading sensing function. This function can improve the safety of vehicles driving on flooded roads, allowing drivers to decide whether to pass through flooded sections to avoid vehicles being flooded due to excessive water depth. The detectors responsible for detecting water depth are installed on the rearview mirrors on both sides, and can work with the inclinometer to identify the ups and downs of the underwater ground. The detected information is displayed in images on the central touch screen. The maximum wading depth of the Range Rover Sport can reach 850mm.

　　The wading detection function can be turned on and off via the touchscreen "4X4i" or the additional function menu. The touchscreen will display the current water depth and the maximum wading depth. When approaching the maximum wading depth, the system will warn the driver through the touchscreen display and sound prompts. If the system limit is exceeded, the touchscreen will be grayed out and the water depth will not be displayed. The wading detection function can only work when the vehicle is driving at a lower speed and the road surface is relatively flat. When the speed exceeds 10km/h or the slope exceeds 10°, the detection function will be suspended. When the speed returns to 10km/h and the road slope is within 10°, the detection function will be turned on again. If the speed exceeds 30km/h for more than 30 seconds, the wading sensing function will be automatically turned off.

　　In addition, when the vehicle is driving in an off-road environment, there may be a large drop in the ground, causing the water depth to change dramatically. The system cannot detect the rapidly increasing water depth, so the wading detection function should not be used in off-road conditions. When the sensor surface is covered with snow, ice, mud or other debris, the detector may have detection errors, which may cause the detection results to be inconsistent with the actual water depth.

　　● Practice the fifth external skill: automatic parking system

　　Domestic configuration models:

　　X-Trail 2014 2.5L CVT Supreme Edition 4WD

　　Manufacturer's suggested price

　　267,800

　　Automatic parking is very useful for many people who are not skilled in driving. This function allows the driver to easily complete the whole process of parking. The vehicle collects the surrounding environment information and measures the distance and angle between itself and the surrounding objects through the camera installed on the side mirror or the radar probe around the body, and then calculates the operation process through the on-board computer and adjusts the steering wheel rotation according to the vehicle speed, so that the vehicle automatically enters the parking space.

　　The 2014 Dongfeng Nissan X-Trail 2.5L CVT Supreme Edition is equipped with an automatic parking system that relies on cameras. It can accurately park the vehicle in three parking spaces: horizontal, vertical, and diagonal. The system uses the rearview mirrors on both sides and the cameras in front and behind the vehicle to replace the sensor detectors that are usually used by other automatic parking systems around the vehicle body. It measures the position and size of the parking space through the images sent back by the camera. The video signal is processed by the on-board computer, which is responsible for the control of the vehicle's steering and power system.

　　When the driver needs to park, he needs to stop the vehicle first. The main reason for this is that the system uses camera monitoring, and the vehicle must be completely stopped before it can effectively scan the parking space lines and surrounding vehicles. Then the driver enters the parking mode through the central control screen, and a blue box will appear on the screen to cover the expected parking space. At this time, let go of both hands and press the parking button to achieve automatic parking.

　　Editor's summary:

　　Drivers no longer have to endure the beating of raindrops on the mirror; no longer have to see the direction clearly because of the glaring lights behind; no longer have to stop because of the unknown depth of the water; no longer have to scratch and accidents because of the blind spot in the field of vision. These changes are inseparable from the continuous improvement of the functions of the side rearview mirror itself and the various electronic safety systems placed on it. The combination of its own design and modern electronic technology makes us more calm when driving the vehicle. And the scene that the side rearview mirror can show us is no longer limited to the limited area in the mirror. What do these differences indicate? I think there is only one answer: driving is safer.