Panasonic has developed a new image sensor technology that can improve the night vision system of the car and improve the safety of the car at night.
It is known that near-infrared light is non-visible light, and an infrared cut-off filter is generally placed between the lens and the sensor to block near-infrared light. However, Panasonic's image sensor technology solution does not require the use of mechanical infrared cut-off filters, as long as the sensitivity of near-infrared light can be electronically controlled under organic CMOS sensors.
So Panasonic applies the technology to the car, and the image displayed by the car night vision system will be clearer. There are some cars that can travel smoothly through the night vision system in the dark, but these cars are more expensive, the price is generally more than 50,000 US dollars, and if you choose a better night vision system, it may cost an extra 2,500 US dollars, so expensive Most people still can't afford the cost. However, with the continuous improvement and popularization of Panasonic's advanced infrared technology, the night machine has become accustomed to the car. It’s just that Panasonic didn’t reveal when this day will come.
So what is the car night vision system?The car night vision system uses infrared technology to make the darkness look as white, making the driver look farther and clearer in the dark. The structure of the night vision system consists of two parts: one is an infrared camera and the other is a light display system on the windshield.
Mercedes-Benz's new S-Class uses a liquid crystal instrument panel. At night, this instrument panel becomes the display of the night vision system. Since the screen position is in front of the driver, it is very convenient to observe. The BMW 7 Series also has a similar system, except that the infrared image is displayed on the LCD screen of the center console, so it is not as convenient to watch as the Mercedes-Benz S-Class. But the BMW 7 Series night vision system also has a very smart advantage. When the infrared detector finds a pedestrian on the road ahead, it will use a bold yellow logo to alert the driver. This not only reflects the technological advancement of the vehicle. Active security.
Night vision system classification and working principleTechnically speaking, night vision systems are divided into two types:
1. Active infrared illumination (short infrared NIR-Near-Infrared Ray)
2. Passive infrared system (FIR-Far Infrared Ray)
Active night vision system
The active night vision system mainly emits a certain intensity of infrared beam by the infrared emitting device, and the image sensor is used to sense the infrared beam reflected from the target object, and the image is displayed on the vehicle display screen. The passive night vision system utilizes the principle that the temperature of most objects in nature is greater than the absolute temperature. In this case, the object will emit a certain wavelength of infrared light, and its spectrum is in the range of more than 3 microns, because the energy of the emitted infrared beam is very high. Weak, need to use expensive dedicated infrared image sensor to perceive the target, mainly for military purposes.
Night vision system works1, infrared light and infrared imaging
Since the advent of the automotive night vision system, infrared technology has been the basis of its dependence. Infrared radiation and infrared imaging are the most basic starting points of the research system. Infrared radiation is also called infrared and infrared light. We know that sunlight is a mixture of colored light. The thermal effect of light is gradually increased from purple to red, and the most thermal effect is outside the red light. We call it "infrared light", which we can see. The color light has the same physical properties, we just can't see it in the eye. Infrared is an electromagnetic wave between light and microwave. The wavelength is 0.75-1000 microns. The wavelength is different. We can divide the infrared into three parts: near-infrared, mid-infrared and far-infrared. In infrared technology, the interaction between infrared and matter is used. The atoms and molecules inside the matter have a certain energy in their constant movement. If there is external stimulation and interference, changing its state of motion, and energy changes, a physical "jump" occurs, that is, the release of energy. A common way to release energy is to release electromagnetic waves. Therefore, infrared is not only one of the components of sunlight, but all objects with temperatures above absolute zero emit infrared light. We convert the infrared radiation pattern of the scene reflection or self-radiation into a pattern that can be observed by the adult eye. This is infrared imaging technology. The image of the object emitted by the infrared light emitted by the object itself is called passive infrared imaging; while the object is irradiated with the infrared radiation source, and the image of the object is taken by the reflected infrared radiation, which is called active infrared imaging, and corresponds to passive Night market technology and active night vision technology.
2, passive infrared night vision technology
Passive infrared night vision technology, also known as infrared imaging technology, uses the infrared radiation of an object to obtain an image of the object. The role of the thermal imaging system is based on the difference between the temperature of the target and the background and the emissivity of the radiation. The radiation temperature measurement technique is used to measure the radiation intensity point by point to form a thermal image of the visible target. The far-infrared camera of the passive infrared night vision system device mainly receives the far-infrared light wavelength of the object itself radiated by 80-14000 nm. The core device from scanning to final imaging is the thermal imager. The subject of the thermal imager includes the target and the background. The difference in radiation between the two is the basis of the thermal image. The radiation of the target and background is absorbed or scattered by the atmosphere and then reflected to the thermal imager. Generally, the receiving component of the thermal imager adopts a single or linear infrared detector, and only takes part of the radiation of the scene. In order to obtain the image of the entire object, the optical detector must be used to sequentially scan the entire object by the infrared detector. Space, the received spatially varying infrared radiation is converted by an infrared detector into a chronologically varying electrical signal that is amplified and converted to a visible image on a cathode ray tube.
3, active infrared night vision technology
Active infrared night vision technology refers to the use of a strong infrared radiation source to illuminate the target while working, using the infrared light reflected from the target to obtain the image of the object. Compared with passive infrared night vision systems, active infrared imaging systems are bulky and energy efficient, but can improve image clarity and resolution. The infrared radiation from the infrared source illuminates the front target, is received by the objective lens group of the reflective optical system, and forms an infrared image of the target on the photocathode surface of the infrared image tube, and the image tube performs spectral conversion, electron imaging and brightness enhancement on the infrared image. Finally, the visible image of the target is displayed on the screen. The active infrared system operates in the near-infrared region of 800 to 1000 nm, and its core component is an infrared image tube, which plays a role in photoelectric image conversion and enhancement. The biggest advantage of the active infrared night vision system is that it can make full use of the narrow beam illumination target emitted by the infrared light source, and the target contrast with the background is large.
4. Comparison of active and passive night vision technologies
Compared with the detection of pedestrians using near-infrared and far-infrared radiation techniques, the results show that far-infrared radiation night vision devices have greater advantages, because pedestrians have large radiant heat and are suitable for far-infrared detection technology.
5, image processing technology
For near-infrared sensors, it is necessary to reduce the glare effect and enhance the image ratio. Intelligent automatic image processing technology is a more advanced technology that can compensate for the low contrast of far infrared sensing images. It can be used to detect and enhance the contour of hot objects. In a process based on knowledge classification, computer programs can be used. Identify objects, for example, to identify pedestrians. It is even possible to combine the available optical and acoustic signals to enhance cognition to further prevent danger. The night vision system has two kinds of black and white display and color display. For the black and white display, objects with different temperatures in front of the screen are colored in black and white and gray color to form a color night vision system, which can display the color of the object in front including The traffic light color at the intersection can give a continuous and clear display of the simulation like a movie. The development of image processing technology plays a crucial role in night vision systems. Future image processing techniques should make images closer to the real environment, better identify obstacles in the environment, help drivers to drive at night, and further improve the safety of night driving.
ConclusionWhen you drive in the night, the scenery is still fascinating in the limited distance before the high beam lights up for you, but there is danger in the darkness in front. Especially in heavy rain, snow, foggy weather, or nighttime driving at dusty and visible visibility, it is the main cause of frequent traffic accidents. Although the automotive lighting technology has made great progress over the years, such as the headlamp system with automatic adjustment of the optical axis and the three-beam headlamp system, although the illumination distance and the alignment error are increased, the risk of driving at night is still better than during the day. Much bigger. According to the National Highway Traffic Safety Administration, although night traffic accounts for only a quarter of the total road traffic, half of the deaths occurred. Therefore, the application of the car night vision system is mainly to prevent problems before they occur. It can be said that the car night vision system will be a safety system with higher value after the airbag and anti-lock braking system.
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