How to solve the problems of surveillance cameras exposed by smog climate

    From the perspective of current real products and system structures, megapixel-level high-definition applications have basically taken shape, such as the front-end megapixel camera, transmission, interface, encoding, image processing application, output, display and other links of product technology, as well as the application system platform. According to the analysis of this topic, they basically have the basis for operation. Although everyone in the industry generally believes that high-definition monitoring is an inevitable trend in the development of the industry and the market, in terms of real market applications, users in various industries are not yet mentally prepared for specific real-world applications.

　　From the user's perspective, they care about image clarity first, but they are also worried that the mixed digital and analog systems used before were mature and stable, and the operation was also handy. Now they are switching to high-definition with millions of pixels. How about the stability? Is it convenient to use? When a failure occurs, is it easy to handle, or does the engineering integrator need to help? In addition, with the recent smog weather, can common camera problems be quickly resolved in field applications? Let us now learn about the installation and debugging of cameras and the analysis of common fault problems.

　　Infrared camera installation issues

　　◇Different media have different transmittance and reflectivity, so different protective cover glasses, especially those with automatic defrosting coatings, will cause a certain attenuation of infrared light, so special attention must be paid during construction;

　　◇ Avoid installing the device in a location that is facing strong light (such as sunlight, lighting, etc.), otherwise it may easily cause over-brightness or light pulling (not a malfunction), which will also affect the life of the CCD;

　　◇The camera should be kept away from humid, dusty, extremely hot, extremely cold, strong electromagnetic radiation and other environments;

　　◇Some infrared lamps do not have irradiation distance parameters, only power numbers, which is a very vague concept, because power consumption, in addition to being converted into infrared light energy, also includes power supply heat loss, circuit heat loss, light source heat loss, filter glass infrared light efficiency, etc. That is, infrared projection lamps with the same power may have very different irradiation distances;

　　◇Manufacturers are increasing, but it is not easy to conduct factory inspections of related products, and the conditions such as technology, testing instruments and equipment are also different. Users should make more comparisons, read the instruction manual carefully before installation, and pay special attention to the precautions to ensure personal and equipment safety;

　　◇ Consider the reflectivity of the scene being photographed. Infrared rays have the same reflection and refraction characteristics as visible light, so when there is no good reflective environment around the target scene (such as buildings, walls, signs), a certain distance margin should be considered;

　　◇When selecting infrared projectors, in addition to their index parameters, other factors need to be considered. Most infrared projectors on the market today are in the 850nm and 940nm bands, and the cameras selected must be able to sense infrared light in these bands;

　　◇Climate conditions such as rain, fog, and dust are factors that restrict the irradiation distance. In addition, the difference in the on-site environment and the reflectivity of the monitored target will also make the night vision effect very different, so it must be tested before installation;

　　◇Try to use electronic control switching devices, whose fuzzy logic capabilities can effectively control the working state of the ICR-CUT filter. Because most manufacturers use simple methods such as photoresistor sensors to control the ICR-CUT filter and the working On/Off state of the infrared projection lamp, the repeated jumps of the critical points are often unsatisfactory.

　　After the haze passes, common camera problems may be effectively solved. Take the infrared hemisphere as an example:

　　Problem 1: Waterproof and heat dissipation effects are not ideal

　　After using for a long time, there will be more or less soda inside the camera (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 taken into account when the machine was installed. When the infrared light starts to work, it will generate a lot of heat. At the same time, due to the insufficient heat dissipation effect of the shell, this will greatly reduce the service life of the camera. To solve this problem, you can consider making the shell of the infrared hemispherical camera into a plurality of wire grooves, which is conducive to heat dissipation.

　　Problem 2: The infrared dome camera series has poor image illumination, whitish images, or bright white apertures at night

　　It should be said that the phenomenon is caused by improper assembly of the machine. During assembly, the photosensitive device (photoresistor) is too far away from the infrared hemispheric camera, which will lead to incomplete activation of the infrared lamp and cause poor illumination of the machine at night. The phenomenon of whitish image or bright white aperture is mainly caused by the infrared light emitted by the infrared light emitting tube being refracted to the lens through the ball cover. To solve this problem, it is necessary to avoid the infrared light from being refracted to the lens surface. Usually, a sponge ring is used to isolate the lens from the infrared light. During assembly, be sure to keep the ball cover close to the sponge ring.

　　Problem 3: Color distortion and color cast of infrared dome cameras

　　It may be that the white balance switch (AWB) is set improperly, or the ambient lighting conditions may change too much. In this case, you should check whether the switch is set to the OFF position and find ways to improve the ambient lighting conditions.

　　Question 4: The image of the night vision infrared dome camera is normal during the day, but turns white at night

　　This phenomenon is generally caused by the presence of reflective objects in the machine's operating environment or by the machine being used in a very small space, due to the reflection of infrared light. To solve this phenomenon, you should first determine whether there are reflective objects in the operating environment and improve the operating environment as much as possible. Secondly, check whether the effective infrared distance of the machine corresponds to the actual operating distance. If a long-distance infrared machine is used in a very small space, the machine image will be whitish due to excessive infrared light.

　　Problem 5: Several black vertical or horizontal bars appear on the screen

　　This situation is usually caused by too much ripple in the output voltage of the machine's power supply. The filtering should be strengthened and a DC regulated power supply with good performance should be used.

　　Problem 6: Insufficient color reproduction during the day

　　I don't know if you have noticed that the color of the infrared dome camera will be more or less biased during the day. The most direct reason is the problem of the camera filter. Generally, the infrared dome camera uses a double-peak filter that can transmit a certain proportion of infrared light. Its advantage is low cost, but because natural light contains more infrared components, when it enters the CCD, it will interfere with color restoration, such as green plants turning gray and so on (especially obvious in the sunny outdoor environment). The use of IRCUT double filter effectively solves this problem. The IRCUT double filter consists of an infrared cut-off filter and a full-spectrum optical glass. When the light is sufficient during the day, the infrared cut-off filter works and the CCD restores the true color. When the light is insufficient at night, the infrared cut-off filter automatically moves away and the full-spectrum optical glass starts to work, so that the CCD can make full use of all the light, thereby greatly improving the infrared performance.

　　Problem 7: The infrared dome camera image is distorted or geometrically distorted

　　This phenomenon may be caused by a problem with the geometric correction circuit of the infrared dome camera or monitor or a problem with the optical lens. It may also be caused by a mismatch between the characteristic impedance of the video connection cable or device and the output impedance of the infrared dome camera.

　　When the above phenomenon occurs, please first check whether the optical lens used is abnormal and whether the input impedance switch of the monitor is set to the 75Ω end, and then check whether the impedance of the video connection cable used is 75Ω.

　　Question 8: The image of the infrared dome camera using the automatic aperture lens is too dark

　　First check whether the EE/AI function switch is set to the AI ​​end, and then check whether the LEVEL potentiometer is adjusted appropriately.

　　Question 9: No image from the infrared dome camera

　　First, check whether the polarity of the external power supply is correct and whether the output voltage meets the requirements (power supply error: DC12V±10%, AC24V±5%). Secondly, check whether the video cable is in good contact. If a manual aperture lens is used, check whether the aperture is open. For an automatic aperture lens, adjust the LEVEL potentiometer to make the aperture in the appropriate position.

　　Problem 10: The image quality of the infrared dome camera is poor

　　a. Check if the lens has fingerprints or is too dirty;

　　b. Check whether the aperture is adjusted properly;

　　c. Check if the video cable has poor contact;

　　d. Check whether there is any problem with the electronic shutter or white balance settings;

　　e. Check whether the transmission distance is too far;

　　f. Check whether the voltage is normal;

　　g. Check if there is any interference source nearby;

　　h. Check that the device is insulated from the elevator and not interfered with when installed in the elevator;

　　i. Check whether the CS interface is connected correctly.