Fault classification of infrared camera

Common problems and solutions of infrared integrated camera

The infrared integrated camera is welcomed by everyone mainly because of its low cost and convenient installation, but there are always some unexpected problems in the use process. The following are the problems I encountered in the production and sales of infrared waterproof cameras for your reference:

The waterproof and heat dissipation effect is not ideal.

After a long time, there will be more or less soda water in it (this phenomenon is mainly concentrated in the northern region). The main reason for this phenomenon is that the sealing effect of the shell is not enough, and the temperature difference was not considered when installing the machine at that time. When the infrared lamp starts to work, it will generate a lot of heat, and the service life of the camera will be greatly reduced because of the insufficient heat dissipation effect of the shell. To solve this problem, in fact, we can consider making the camera shell into multiple trunking, which is beneficial to heat dissipation.

The effect of night vision is not ideal.

This phenomenon is mainly manifested in the effect of flashlight or insufficient distance and so on. In fact, this problem is mainly caused by the angle and function of infrared light. The infrared lamp used in our infrared camera is also called 850 infrared emitting tube, with a peak wavelength of 850 and an angle of 5-60 degrees. The smaller the angle of the infrared emission tube, the farther the irradiation distance, and the more obvious the flash effect. On the contrary, the greater the angle, the less the flashlight effect, but the distance is greatly reduced. To solve this problem, it mainly depends on what kind of effect and cost manufacturers want to pursue. But you may have overlooked a question-what is the power and diameter of the infrared lamp? When the appearance and size of the infrared lamp are the same, in fact, you have no way to know the power, and the only way may be to test it in kind. From my personal experience in making infrared cameras to solve this problem, I adopted a multi-angle infrared lamp mixed installation method, which can make full use of resources and give consideration to both distance and distance.

Insufficient color reproduction during the day

We don't know if you have noticed that the color of the infrared integrated camera will be more or less color cast during the day. The most direct reason is the problem of the camera filter. Generally, an integrated infrared camera adopts a bimodal filter that can transmit a certain proportion of infrared light, which has the advantage of low cost. However, because natural light contains more infrared components, it will interfere with color reduction after entering CCD, such as green plants turning gray and so on (especially in sunny outdoor environment). Using IPC cut-off filter can effectively solve this problem. IPCUT double filter consists of infrared cut filter and full spectrum optical glass. When there is enough light in the daytime, the infrared cut-off filter works and the CCD restores the true color. When there is insufficient light at night, the infrared cut-off filter is automatically removed, and the full-spectrum optical glass starts to work, so that the CCD can make full use of all the light, thus greatly improving the infrared performance.

Repeated jump of critical point

This is because some cameras, whether equipped with IRCUT double filters or bimodal filters, can't work stably in some complex lighting environments. At the same time, because most manufacturers use simple methods such as photoresistor sensor to control the working state of IRCUT dual-mode filter, the repeated jump of its critical point is not satisfactory. However, if it is controlled by intelligent chip, its fuzzy logic ability can effectively control the working state of IPCUT double filter. In other words, many manufacturers are reluctant to invest in this.

Image color cast problem

All black and white cameras are sensitive to infrared light. Under visible light, infrared light is a kind of stray light of color camera, which will reduce the clarity and color reproduction of color camera. The camera uses CCD to sense all light (visible light, infrared light and ultraviolet light, etc.). ), which makes the images taken during the day very different from those produced by our naked eyes only observing visible light. Because CCD senses infrared light, it will interfere with the operation of DSP and lead to color cast. Aiming at the color cast problem of infrared camera monitoring image, the industry has carried out a lot of technical research and development, and there are three main methods to solve this problem. One is to debug RGB tone DSP processing on CCD, which is an expedient measure, and not every manufacturer has this chip processing ability; Secondly, by switching filters, all filters for filtering infrared rays are used during the day, and an ordinary time film is used to trim the light at night; Thirdly, by changing the model and replacing the IRCUT camera with an infrared camera with dual CCD, the service life of the infrared camera can be extended without color cast during the day.

Heat dissipation problem

Due to the high calorific value of the infrared lamp, after the infrared lamp is started, there will be heat concentration in front of the infrared camera during the whole working period (12 hours), which will affect the normal work of other components such as the camera. For example, if 50 infrared panels with a ratio of ￠5 work for a long time, the temperature on the LED panel can almost reach 90 degrees.

Because the radiation power of infrared LED is directly proportional to the current, many non-standard manufacturers increase the current to improve the irradiation effect. However, the greater the current, the higher the temperature. Although the irradiation effect is improved, the machine itself will be greatly damaged due to the overheating of LED. Among them, the CCD behind the LED board is the most direct victim. General CCD can only support 60-70 degrees long.

In order to solve this problem, different manufacturers adopt different methods. Generally speaking, there are the following types:

1, reduce the current. Replacing high-power infrared lamp with low-power infrared lamp reduces heat dissipation, but the effect is definitely not as good as the latter when it is irradiated at a long distance.

2. Adding a cooling fan inside the machine is definitely effective, but the test of the fan is very strict, and adding a fan is also a test of the shell design, so it is necessary to ensure that it is beautiful and practical.

3. Use constant current power supply. Keep the current constant and control the LED to dissipate heat.

4. Grouping arrangement of 4.LED lights. For example, 24 infrared rays can be arranged in three groups to reduce heat.

5. Selection of structural materials. For example, LED panels and housings are made of aluminum alloy and other materials with good heat dissipation.

6. The forced cooling and automatic heating and cooling air conditioner is adopted to automatically adjust the internal temperature of the machine body, which solves this problem well.

Life of infrared lamp

From the perspective of external red light, extending life and increasing distance are often contradictory. Because if manufacturers need to increase the irradiation distance of infrared lamps, it will inevitably increase the power of infrared lamps and shorten the life of infrared lamps. In order to blindly pursue the distance of infrared lamp, some manufacturers deliberately increase the power of infrared lamp, which greatly reduces the life of infrared lamp. Moreover, with the increase of power, the internal temperature of the camera rises, and the camera is easy to be damaged, resulting in a vicious circle. In this case, we can't increase the power supply current to improve the brightness of the infrared lamp and make it work overload, although the infrared performance is optimized on the surface, which seriously affects the life attenuation of the infrared lamp. In order to improve the life of infrared lamps, we must first ensure that infrared lamps are not loaded, and at the same time increase the number of infrared lamps to ensure the effective distance; Some manufacturers increase the heat dissipation capacity of the fuselage by using high thermal conductivity materials such as aluminum substrate, increasing the use of air-cooled devices and increasing the shell area, thus improving the service life. In the circuit control part, some manufacturers also use the law of pulse width modulation to keep the current of infrared lamp constant, thus reducing the heat of infrared lamp and prolonging its life. After adopting the law of pulse width modulation, no matter how the external input current fluctuates, the current entering the infrared lamp through the circuit is very stable, thus ensuring the maximum efficiency of the infrared lamp and prolonging its service life.

Red storm problem

What is a red storm? Red storms are caused by visible light components in infrared rays.

The infrared lamp can have no red explosion at all (using infrared tubes with wavelength of 940 ~ 950 nm) or only a slight red explosion. Sino-Shandong communication company adopts American AUCSITER infrared technology. By reducing the heat consumption of infrared lamp and adjusting the angle of infrared light on the premise of ensuring the power of infrared lamp, the effective utilization rate of infrared lamp can reach 90%. In the choice of infrared lamp, the infrared lamp with longer wavelength (9 10nm) is selected to strictly reduce the red storm and achieve the effect of micro-red storm.

Fogging and Frosting of Infrared Camera

Fog and frost are formed by the condensation of saturated water vapor in the air when the weather is cold. Due to the strength of the cold environment, it condenses into frost and fog respectively. In the working process of infrared cameras, especially outdoor cameras, due to seasonal changes, temperature difference between day and night, rain and snow environment and other reasons, fog or frost often forms on the window glass of the protective cover, which leads to the camera being unable to see the objects clearly and directly affects the monitoring effect. By adopting advanced electronic defrosting circuit, Zhonglu Communication Company can effectively control the saturated water vapor concentration in the cavity and realize automatic defogging and defrosting.

Window cleaning of infrared camera

The infrared hemisphere camera works in rain, snow or dusty environment, and the window glass of the protective cover is prone to dirt, which will block the camera's line of sight. The solution is usually to add a wiper to the protective cover and clean the glass by controlling the wiper; Another method is to use invisible wiper window glass. Compared with ordinary window glass, invisible wiper window glass has the functions of resisting water, dust and snow.

Constant temperature of infrared camera

Due to the configuration of high heat value of the infrared lamp, after the infrared lamp is started, there will be heat concentration at the front end of the infrared hemispherical camera during the whole working period (calculated by 12 hours), that is, the temperature at the front end of the cavity is high, and if it cannot be evenly radiated, it will affect the normal work of other components such as the camera. China-Shandong Communication Company has solved this problem well by designing and using automatic heating and cooling air conditioners with forced heat dissipation and forced cooling.

The automatic heating and cooling air conditioner adopts the Peltier effect principle, which can automatically adjust the temperature control circuit to keep the temperature in the protective cover within the normal working temperature range of the camera. When leaving the factory, the temperature in the protective cover is set below +5℃ when heating and above +40℃ when cooling. Experiments show that the infrared hemispherical camera can work normally in the outdoor natural environment of -40℃ ~+70℃ (direct sunlight).

Totally enclosed infrared camera

In addition to constant temperature, another advantage of using automatic heating and cooling air conditioning is that the infrared camera can be completely turned off without leaving any cooling holes to prevent dust, moisture and corrosive gases from entering, thus adapting to harsh environments with heavy dust, such as large coal mines.

Infrared camera

Infrared integrated camera includes hemispherical infrared integrated camera, fast spherical infrared integrated camera, infrared integrated camera combined with tripod head and infrared integrated camera with built-in lens.

Compared with the traditional camera, the infrared integrated machine is small and beautiful, with advantages in installation and more convenient. It has direct sockets for power supply, video and control signals, unlike the wiring trouble of traditional cameras. The patents of integrated imaging system (lens), CCD and DSP technology have been mastered by internationally renowned manufacturers. Compared with traditional cameras, the quality of the all-in-one machine can be better controlled. At the same time, the integrated camera has a wide monitoring range and high cost performance. The traditional camera positioning system is not flexible enough and needs manual focusing, and the biggest advantage of the integrated camera is the automatic focusing function.

Being able to achieve good waterproof function is also one of the characteristics of infrared integrated camera. Outdoor integrated camera has waterproof function, but traditional camera needs to be used with tripod head and protective cover to achieve waterproof function. There is also a diving integrated camera specially developed for underwater operations.

In addition, the infrared lamp integrated with the infrared integrated camera can automatically turn on even at night when the illumination is lower than a certain value, thus achieving a stable imaging effect.

Infrared integrated cameras are mostly used in government projects, high-grade high-rise buildings, shopping malls, schools, hotels, hotel lobbies and so on. In addition, there are dust-proof products specially suitable for places with high environmental requirements, such as hospital operating rooms, and explosion-proof products with low temperature and spark-free motors. Other professional integrated cameras, such as military, aviation, polar, seabed and biochemical environment, have different special functions, such as anti-high-pressure, anti-corrosion, anti-vibration and so on.