With the security issues gradually becoming the focus of social attention, the development of security monitoring technology is also increasingly concerned by all aspects of society, only visible light monitoring can no longer meet people's monitoring requirements, 24-hour continuous monitoring is now in the monitoring system must The less important part. To achieve all-weather continuous surveillance, it is necessary to implement the technology of night vision cameras. At present, infrared night vision technology is adopted. Infrared camera technology includes passive infrared camera technology and active infrared camera technology.
Passive infrared
Passive infrared camera technology uses the principle that any object can radiate electromagnetic waves above absolute (-273°C). Due to differences in the radiating ability of different objects and even different parts of the same object and their reflection on infrared rays, the radiation difference between the object and the background environment, and the difference in the radiation of each part of the scene itself, the infrared detector can convert the radiation signals of different intensity into different Corresponding electrical signals are then subjected to amplification and video processing to form video images that can be observed by the human eye. The thermal images can present the undulations of the various parts of the scene and thus can display the characteristics of the scene.
The thermal image and the visible image of the same target are different. It is not the visible light image that the human eye can see, but the temperature distribution image of the target surface. It cannot clearly identify the detailed features of the target and cannot meet the requirement of “evidence†and is passive. Infrared cameras are costly and mostly used in military applications. Currently, there are few applications in the field of surveillance.
Active infrared
Active infrared camera technology uses "infrared light-emitting diodes" to artificially generate infrared radiation to produce infrared light that cannot be seen by the human eye and can be captured by ordinary cameras. It assists the "illumination" of scenery and the environment, and uses the camera's image sensor to sense the characteristics of infrared light. Feel the infrared light reflected from the surrounding environment to obtain a clearer black and white image and realize night vision monitoring. Therefore, most of the current infrared camera technology uses active infrared camera technology and uses infrared light to match the camera.
Active infrared technology is currently more mature in four forms:
Traditional LED Infrared Lamps: The illuminant consists of a certain number of infrared light emitting diode arrays. The infrared emitting diode is made of a material with high infrared radiation efficiency, and a PN junction is made of a material with high infrared radiation efficiency. A forward bias voltage is applied to the PN junction to inject infrared light. The spectral power distribution is center wavelength of 830-950 nm, and the half-peak bandwidth is about 40 nm. It is a narrow band. The distribution is the CCD-sensible range.
Second-generation array-integrated infrared light source: Based on the original LED infrared technology, advanced packaging technology is adopted, and dozens of high-power and high-efficiency infrared crystals are packaged on a single plane, and multiple infrared luminescences are integrated. The chip is in a small area and has been processed by "thermoelectric separation" so that the entire part can be placed on a heat sink of any size and shape, thereby solving the problem of heat dissipation and no longer damaging peripheral electronic components due to high temperature. .
The third-generation dot-matrix infrared light source: Using highly integrated LED array chip technology, the output of a single LEDArray is about 800mW~3.6W, and the electro-optical conversion efficiency is about 25%. The luminous body is a single light source, and the luminous angle can be large or small.
Laser infrared lamp: It belongs to a semiconductor laser. It uses semiconductor materials to recombine holes and electrons, and the electron energy level is reduced to release electrons to generate light energy. Then the photons form laser light in the direction of the resonance specification photon. The laser has a good directionality, which is characterized by a small beam angle, energy concentration, and sufficient light intensity to travel farther, making it ideal for long-distance lighting.
Active infrared technology and passive infrared technology contrast
Active infrared cameras require the use of infrared transmitters. The advantage is that they can display the details of the target and the cost is low. The disadvantage is that the distance between them is relatively close, and the imaging effect is easily affected by the environment, especially in fog, snow and rain. Under such severe weather conditions, it is mainly used to detect targets.
Passive infrared cameras do not require auxiliary light sources. The advantage is that the penetrating power is strong and the irradiation distance is long. The disadvantage is that only the surface temperature distribution image of the target can be presented, which is mainly used to find the target.
Comparison of four active infrared technologies
Traditional LED infrared light. It is currently the most commonly used infrared light emitting device, and it occupies more than 95% of the market, but its quality is uneven, and the price difference is also large.
The advantages are small size, simple production process, easy quality assurance, low heat generation, reasonable light emitting optical system, no red storm (using 940-950nm wavelength) or only weak red storm (red storm has visible red light) With a service life of several thousand hours or more, it is an ideal device for making infrared lamps and is widely used for night vision monitoring.
The disadvantage is poor heat treatment, resulting in too high ambient temperature and affecting the life of nearby electronic components (such as camera boards, control circuit boards, etc.). The most spurious is that its light decays too quickly, and it is generally less than a year to see the night vision screen. Because it is encapsulated with "epoxy resin", "epoxy resin" will break when exposed to heat. After a long time, the fracture surface will become more and more, and some light will be refracted when infrared rays pass through each fracture surface. This is the main reason why traditional LED lights have fast decay and short life.
The second generation of arrayed integrated light sources. It integrates a number of infrared light emitting chips in a small area, and "thermoelectric separation" processing, making the entire part can be placed on any size, arbitrary shape of the heat sink, thus solving the heat problem, no longer due to high temperature Injures other electronic components around the site. And due to the use of silicone encapsulation, the material does not break and greatly reduce the light attenuation, and the lifetime is 5-10 times longer than the traditional LED lamp.
The disadvantage is that the price is much higher than traditional LED lights. Moreover, in order to reduce the light transmission angle by using a lens to match the angle of the camera lens, it is inevitable that many light points deviate from the center of the lens (commonly known as: eccentricity), resulting in poor light transmission efficiency, as compared with the same power. For traditional LED lights, "not bright enough" is its disadvantage.
The third generation of dot matrix infrared light source (LEDArray). Its electro-optical conversion efficiency is about 25%, which is 2.5 times higher than that of the first generation of ordinary infrared LED, and its power consumption is reduced by 2.5 times. The output of a single LEDArray is about 800mW~3.6W, and the brightness is about the output of a conventional single LED. ~100mW more than 100 times; LEDArray effective life of 10,000h, more than 5 times the effective life of ordinary LED; using metal, easy to maintain low temperature operation, good heat dissipation; LED Array half power angle of 10 ° ~ 120°, can produce (180° shape) light emitting surface, solve the "flashlight effect" that ordinary LED indoor space can not be evenly illuminated; LEDArray is a highly integrated chip, so its volume is much smaller than other infrared products under the same brightness index ;
The third generation of dot matrix infrared light source (LEDArray). Its electro-optical conversion efficiency is about 25%, which is 2.5 times higher than that of the first generation of ordinary infrared LED, and its power consumption is reduced by 2.5 times. The output of a single LEDArray is about 800mW~3.6W, and the brightness is about the output of a conventional single LED. ~100mW more than 100 times; LEDArray effective life of 10,000h, more than 5 times the effective life of ordinary LED; using metal, easy to maintain low temperature operation, good heat dissipation; LED Array half power angle of 10 ° ~ 120°, can produce (180° shape) light emitting surface, solve the "flashlight effect" that ordinary LED indoor space can not be evenly illuminated; LEDArray is a highly integrated chip, so its volume is much smaller than other infrared products under the same brightness index ;
The third-generation dot-matrix infrared light source has a price closer to the traditional LED and is currently the best technology in the infrared lighting market, and it is slowly replacing the traditional LED infrared lighting technology. Laser lighting technology.
Laser illumination can reach up to 3,000 meters, which is more than 20 times the irradiation distance of conventional products (120-150 meters). The laser has good directionality, the beam angle is small, the energy is concentrated, and there is still enough light intensity to travel farther, so it is suitable for long-distance lighting. It is suitable for large-scale environmental monitoring, forest fire prevention, scenic spot monitoring, and port terminals. Monitoring, oilfield monitoring, etc.
However, the production process of the laser infrared lamp is not like the LED infrared lamp, and its production process requirements are very high. At the same time, the production of laser infrared lamps requires a huge investment, which is something that ordinary manufacturers cannot accomplish.
Future development direction of the infrared camera <br> <br> infrared camera market is currently very confusing, mainly because of the lack of uniform industry standards. For example, the irradiation distance of infrared lamps is often the highlight of various companies' propaganda, which is not the same as each other, and the distance from which the radiation is measured is measured under which conditions. At that time, the ambient illumination is how the picture quality is presented. It is impossible to know how, but this is exactly the most serious test that infrared cameras face. Solving this problem has become a common concern among companies.
Active infrared technology from the early efficiency of only 5%, to the current efficiency of 25-30% of the LEDArray technology, to meet the short-range infrared night vision technology breakthrough in the distance, and laser lighting technology is to achieve long-range night As one of the best ways to monitor, and light intensity is much stronger than conventional light sources, long-range night vision technology is a trend in the future night vision surveillance market.
The fusion of active infrared technology and passive infrared technology will be one of the trends in the future. The use of passive infrared technology to find the target with strong penetrating power and long-distance radiation characteristics. The principle of active infrared technology lighting is used to collect the target details, which can be Central and distant distance monitoring provides strong "evidence."
In addition, blending with another type of night vision technology, the micro-light technology, is also one of the future development directions. In the period of continuous improvement of both micro-light and infrared technologies, considering the complementarity between the two, no increase in existing Based on the technical difficulty, how to merge the low-light image with the infrared image to obtain a better observation effect, these two technologies have become the hot research of the development of the night-vision technology.
Passive infrared
Passive infrared camera technology uses the principle that any object can radiate electromagnetic waves above absolute (-273°C). Due to differences in the radiating ability of different objects and even different parts of the same object and their reflection on infrared rays, the radiation difference between the object and the background environment, and the difference in the radiation of each part of the scene itself, the infrared detector can convert the radiation signals of different intensity into different Corresponding electrical signals are then subjected to amplification and video processing to form video images that can be observed by the human eye. The thermal images can present the undulations of the various parts of the scene and thus can display the characteristics of the scene.
The thermal image and the visible image of the same target are different. It is not the visible light image that the human eye can see, but the temperature distribution image of the target surface. It cannot clearly identify the detailed features of the target and cannot meet the requirement of “evidence†and is passive. Infrared cameras are costly and mostly used in military applications. Currently, there are few applications in the field of surveillance.
Active infrared
Active infrared camera technology uses "infrared light-emitting diodes" to artificially generate infrared radiation to produce infrared light that cannot be seen by the human eye and can be captured by ordinary cameras. It assists the "illumination" of scenery and the environment, and uses the camera's image sensor to sense the characteristics of infrared light. Feel the infrared light reflected from the surrounding environment to obtain a clearer black and white image and realize night vision monitoring. Therefore, most of the current infrared camera technology uses active infrared camera technology and uses infrared light to match the camera.
Active infrared technology is currently more mature in four forms:
Traditional LED Infrared Lamps: The illuminant consists of a certain number of infrared light emitting diode arrays. The infrared emitting diode is made of a material with high infrared radiation efficiency, and a PN junction is made of a material with high infrared radiation efficiency. A forward bias voltage is applied to the PN junction to inject infrared light. The spectral power distribution is center wavelength of 830-950 nm, and the half-peak bandwidth is about 40 nm. It is a narrow band. The distribution is the CCD-sensible range.
Second-generation array-integrated infrared light source: Based on the original LED infrared technology, advanced packaging technology is adopted, and dozens of high-power and high-efficiency infrared crystals are packaged on a single plane, and multiple infrared luminescences are integrated. The chip is in a small area and has been processed by "thermoelectric separation" so that the entire part can be placed on a heat sink of any size and shape, thereby solving the problem of heat dissipation and no longer damaging peripheral electronic components due to high temperature. .
The third-generation dot-matrix infrared light source: Using highly integrated LED array chip technology, the output of a single LEDArray is about 800mW~3.6W, and the electro-optical conversion efficiency is about 25%. The luminous body is a single light source, and the luminous angle can be large or small.
Laser infrared lamp: It belongs to a semiconductor laser. It uses semiconductor materials to recombine holes and electrons, and the electron energy level is reduced to release electrons to generate light energy. Then the photons form laser light in the direction of the resonance specification photon. The laser has a good directionality, which is characterized by a small beam angle, energy concentration, and sufficient light intensity to travel farther, making it ideal for long-distance lighting.
Active infrared technology and passive infrared technology contrast
Active infrared cameras require the use of infrared transmitters. The advantage is that they can display the details of the target and the cost is low. The disadvantage is that the distance between them is relatively close, and the imaging effect is easily affected by the environment, especially in fog, snow and rain. Under such severe weather conditions, it is mainly used to detect targets.
Passive infrared cameras do not require auxiliary light sources. The advantage is that the penetrating power is strong and the irradiation distance is long. The disadvantage is that only the surface temperature distribution image of the target can be presented, which is mainly used to find the target.
Comparison of four active infrared technologies
Traditional LED infrared light. It is currently the most commonly used infrared light emitting device, and it occupies more than 95% of the market, but its quality is uneven, and the price difference is also large.
The advantages are small size, simple production process, easy quality assurance, low heat generation, reasonable light emitting optical system, no red storm (using 940-950nm wavelength) or only weak red storm (red storm has visible red light) With a service life of several thousand hours or more, it is an ideal device for making infrared lamps and is widely used for night vision monitoring.
The disadvantage is poor heat treatment, resulting in too high ambient temperature and affecting the life of nearby electronic components (such as camera boards, control circuit boards, etc.). The most spurious is that its light decays too quickly, and it is generally less than a year to see the night vision screen. Because it is encapsulated with "epoxy resin", "epoxy resin" will break when exposed to heat. After a long time, the fracture surface will become more and more, and some light will be refracted when infrared rays pass through each fracture surface. This is the main reason why traditional LED lights have fast decay and short life.
The second generation of arrayed integrated light sources. It integrates a number of infrared light emitting chips in a small area, and "thermoelectric separation" processing, making the entire part can be placed on any size, arbitrary shape of the heat sink, thus solving the heat problem, no longer due to high temperature Injures other electronic components around the site. And due to the use of silicone encapsulation, the material does not break and greatly reduce the light attenuation, and the lifetime is 5-10 times longer than the traditional LED lamp.
The disadvantage is that the price is much higher than traditional LED lights. Moreover, in order to reduce the light transmission angle by using a lens to match the angle of the camera lens, it is inevitable that many light points deviate from the center of the lens (commonly known as: eccentricity), resulting in poor light transmission efficiency, as compared with the same power. For traditional LED lights, "not bright enough" is its disadvantage.
The third generation of dot matrix infrared light source (LEDArray). Its electro-optical conversion efficiency is about 25%, which is 2.5 times higher than that of the first generation of ordinary infrared LED, and its power consumption is reduced by 2.5 times. The output of a single LEDArray is about 800mW~3.6W, and the brightness is about the output of a conventional single LED. ~100mW more than 100 times; LEDArray effective life of 10,000h, more than 5 times the effective life of ordinary LED; using metal, easy to maintain low temperature operation, good heat dissipation; LED Array half power angle of 10 ° ~ 120°, can produce (180° shape) light emitting surface, solve the "flashlight effect" that ordinary LED indoor space can not be evenly illuminated; LEDArray is a highly integrated chip, so its volume is much smaller than other infrared products under the same brightness index ;
The third generation of dot matrix infrared light source (LEDArray). Its electro-optical conversion efficiency is about 25%, which is 2.5 times higher than that of the first generation of ordinary infrared LED, and its power consumption is reduced by 2.5 times. The output of a single LEDArray is about 800mW~3.6W, and the brightness is about the output of a conventional single LED. ~100mW more than 100 times; LEDArray effective life of 10,000h, more than 5 times the effective life of ordinary LED; using metal, easy to maintain low temperature operation, good heat dissipation; LED Array half power angle of 10 ° ~ 120°, can produce (180° shape) light emitting surface, solve the "flashlight effect" that ordinary LED indoor space can not be evenly illuminated; LEDArray is a highly integrated chip, so its volume is much smaller than other infrared products under the same brightness index ;
The third-generation dot-matrix infrared light source has a price closer to the traditional LED and is currently the best technology in the infrared lighting market, and it is slowly replacing the traditional LED infrared lighting technology. Laser lighting technology.
Laser illumination can reach up to 3,000 meters, which is more than 20 times the irradiation distance of conventional products (120-150 meters). The laser has good directionality, the beam angle is small, the energy is concentrated, and there is still enough light intensity to travel farther, so it is suitable for long-distance lighting. It is suitable for large-scale environmental monitoring, forest fire prevention, scenic spot monitoring, and port terminals. Monitoring, oilfield monitoring, etc.
However, the production process of the laser infrared lamp is not like the LED infrared lamp, and its production process requirements are very high. At the same time, the production of laser infrared lamps requires a huge investment, which is something that ordinary manufacturers cannot accomplish.
Future development direction of the infrared camera <br> <br> infrared camera market is currently very confusing, mainly because of the lack of uniform industry standards. For example, the irradiation distance of infrared lamps is often the highlight of various companies' propaganda, which is not the same as each other, and the distance from which the radiation is measured is measured under which conditions. At that time, the ambient illumination is how the picture quality is presented. It is impossible to know how, but this is exactly the most serious test that infrared cameras face. Solving this problem has become a common concern among companies.
Active infrared technology from the early efficiency of only 5%, to the current efficiency of 25-30% of the LEDArray technology, to meet the short-range infrared night vision technology breakthrough in the distance, and laser lighting technology is to achieve long-range night As one of the best ways to monitor, and light intensity is much stronger than conventional light sources, long-range night vision technology is a trend in the future night vision surveillance market.
The fusion of active infrared technology and passive infrared technology will be one of the trends in the future. The use of passive infrared technology to find the target with strong penetrating power and long-distance radiation characteristics. The principle of active infrared technology lighting is used to collect the target details, which can be Central and distant distance monitoring provides strong "evidence."
In addition, blending with another type of night vision technology, the micro-light technology, is also one of the future development directions. In the period of continuous improvement of both micro-light and infrared technologies, considering the complementarity between the two, no increase in existing Based on the technical difficulty, how to merge the low-light image with the infrared image to obtain a better observation effect, these two technologies have become the hot research of the development of the night-vision technology.
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