Any product will appear in the course of a series of issues, how to find and remove a critical problem. The infrared cameras in use during the course will also have a wide variety of problems, Here's to analyze the infrared camera in the everyday use of several kinds of problems occur.
Infrared Wave issue:
Some manufacturers to be able to create Infrared wave red-infrared light as a technical issue to promote, as if there is a infrared wave of low-skilled, non-infrared wave is high. In fact, whether the infrared wave is just a matter of choice, not a technical problem, More than 700nm wavelength of light is called infrared light, 900nm infrared basically no more than infrared wave, the shorter the wavelength, the infrared wave is stronger, the higher the degree of infra-red sensors. Now on the market, there are two main infrared light, one is a slight infrared wave, the wavelength of about 850nm, one is no infrared wave, the wavelength of about 940nm. With a video camera, the sensitivity in the 850nm wavelength than in the 940nm wavelength to 10 times better sensitivity, so that there is a slight red storm 850nm infrared light has a higher efficiency, it should be used as infrared night vision surveillance Preferences
Life isuue:
The life of the camera up to 10 years, infrared lamp life will they be able to reach this level? Correctly answer this question, we must first understand the current infrared lamp manufacturing principles. There are currently three types of infrared light manufacturing model: 1, halogen lamps, two, multi-chip led, 3, single-chip led. Halogen is a more traditional technology, high energy consumption, heat large, life is shorter because the use of inefficient, the market is expected to gradually fade out.
Multi-chip led, there are two forms, one is with 4-8 chips; another kind of light-emitting array chip, containing 10-30 chips. Why do multi-chip? Some theories from the manufacturers is: Infrared lamp irradiation distance is not enough because the energy is not enough, more chips together, of course, the energy on the large, assumed that exposure to longer distances. To be sure, longer distances require greater energy, but not issued a number of infrared light infrared light, the camera will be able to receive the number of infrared light.
Multi-chip led the inherent shortcomings of its structure, there is no light on the focus of light-emitting optical system unreasonable, there is light efficiency is relatively low (of course, is several times stronger than halogen), its advantages not effectively play. For example array led, currents up to 1000ma, basically just a penny coin size, heat dissipation becomes a problem. Most afraid of is that heat can be led, ah, strange if it is not bad. Meanwhile, the multi-chip led production requirements are very strict, Each chip can have a little difference in performance, or a chip, then broken machine on all finished. Overall, relative to the single-chip led, the multi-chip led the life is not enough.
The singel chip process is very simple,the quality is easy to guarantee, heat is low, light-emitting optical system is reasonable, is the ideal device to do infrared light, in theory, life of up to 10 thousand hours. Well, not all of the life of a single-chip led lamps are very well?
In fact,it’s not case. There are many reasons for that, for example, some chips led a low level of impurities exceeded; some production processes were not accepted, there is leakage phenomenon; some super-power use, rated 20ma, but the use of 50ma above; Some do not have protection circuits, or circuit design unreasonable, these will lead to a single-chip led infrared light quickly broken.
To ensure the infrared lamp life, the led first to use high-grade chips. High-grade chip, big power, consistency is good, light-emitting efficiency, heat is very small, led a high level of quality than ordinary led a good 10 times, of course, price is very expensive. Second, the optical system design should be reasonable, light should be uniform, higher utilization, faster heat dissipation. Third, we must strictly control the operating voltage. led to the voltage is very sensitive, voltage slightly higher led the die will be burned: the voltage is slightly lower then the amount of light will be greatly reduced. The best match of high-quality switching power supply, AC input voltage is preferably from 170 volts to 270 volts can do a better regulation, the power supply to suit the harsh environment. Fourth, the input power lines against the best selection of high / low temperature, ultra-soft, anti-bending. There is a manufacturers of infrared light, input power cord can be minus 60 degrees at low temperature, high temperature and zero at 250 degrees normal use, minus four, 50-degree cable is still soft, like silk in general, such products will be worthy of trust.
Angle Issue:
Infrared light is not the bigger the better perspective? Whether manufacturers or engineering companies acknowledge this and take it for granted, they think the greater the infrared light emission angle, choose the greater room for the lens, choose the wide-angle lens is not a "flashlight" phenomenon . So, we all say that they desperately perspective of infrared light is how big. This seems very reasonable to say is very scientific.
First, using large angle-degree angle of the infrared light with the players with the lens, there is light waste. For example, an infrared light emitting angle is 80 degrees (equivalent to f3.5mm lens angle), if applied with f35mm the lens, Then there will be a considerable part of the just outside the camera field of view, that is part of the infrared light is wasted. In general, the perspective of infrared light to be consistent with the perspective of the lens, the effect is the best. For instance, some infrared lamps, light emission point of view is expressed in the lens focal length. its sk-4.2w-16 infrared light, the meaning is this: "-4.2w" said the lamp rated power is 4.2 watts; "-16" for The angle of light emission in line with the f16mm camera lens, the two can be complementary. its infrared light by the angle classification, currently including "-4", "-8", "-16", "-35" Four series , can be used on the market supporting the lens.
Second,not infrared light emission point of the larger picture, the better. Some occasions, if the angle of infrared light is too large, will also affect the imaging. Such as Corridor, because of its "narrow" feature, if the infrared light emission point of view is too large, then the near edge of the image will be too bright to form a "light screen" phenomenon; distant center becomes invisible, and only a whitish phenomenon. Therefore, the corridor should be the camera angle of infrared light one-half or one-third of one.
Third, can use the "take lamp" technology, with two narrow-angle infrared lights and adjust the position, can achieve wide-angle light effect on the market, "Nighthawk" series of infrared night vision systems, is to use "take lamp" This kinds of technology, so that they were both wide-angle long-term perspective. in the same power conditions, "then light" technology to enhance the role of the double distance.
Overall, the infrared light emission point of view the problem is also the choice of technical problems. A different lens focal length should be chosen corresponding firing angle of the infrared light, infrared light emission point of view no matter what kind of conditions should not be larger than the lens perspective, and in the narrow context of the application, on the choice of a smaller angle than the lens as well as one-third of the infrared light. narrow-angle infrared light through the mix, can be the ideal wide-angle effect, the effect better, lower cost .
Lighting transmission issue:
The relative aperture determines the lens's ability to pass light, the relative aperture of f1.0 lens pass the amount of light is relative aperture f2.0 lens pass four times the amount of light. The same cameras, infrared lights, respectively, with the above-mentioned two kinds of lens, IR Distance of differential could be doubled.
Large-aperture lens in infrared surveillance, better than the conventional four to ten times the normal lens, by all reason should be monitored must be matched infrared night vision products. However, because of high costs, technical difficulties, the vast majority of manufacturers do not have the infrared for the handling capacity.
As the well-known reasons, the market flooded with a large number of standard f value of the virtual camera, especially the zoom lens, marked only with a short telephoto focal non-standard and thus misleading the contractors, causing the user simply can not discern someone's selling the real thing, someone's shoddy. Recommended that users go to the professional large-scale manufacturers to buy the lens.
Focus offset issue:
Visible and infrared light due to the different wavelengths, imaging, focus is not on a plane, resulting in visible during the day under the condition of the pictures are clear, while the infrared light at night under the conditions of ambiguity, or at night under the conditions of infrared light images clear and visible during the day under the conditions of image blurring. Can be three solutions. First, an integrated camera with autofocus; second, with special focus on non-shift lens; third, the adjustment of a professional tool, even under the existing conditions, the lens can be achieved are not offset.
Color issue:
All the black and white cameras are sensitive infrared light. Under the conditions of infrared light in the visible color camera for a hybrid in terms of light and color cameras will reduce the clarity and color reproduction, color filters that block infrared camera imaging to participate. To make color infra-red camera sensors now have two approaches, first, switch filters, blocking the infrared light in the visible under the conditions of entry; in the absence of visible light, remove the filter under the conditions, so that the infrared to enter such programs received image quality is good, but costs are high and the switching mechanism would lead to a certain failure rate. Secondly, in the filter to open a specific infrared channel, allowing the same wavelength with the infrared light infrared light come in, that it would not increase costs, but slightly worse color reproduction.
Sensitivity issue:
Infrared night vision surveillance camera sensitivity is a core part of. Sensitivity and better ability of the infrared sensor stronger. Of course, the sensitivity of the better price the more expensive cameras. In general, less than 50 meters IR night vision systems, use 0.1 lux camera is better; 50 meters to 100 meters of 0.01 lux night vision system should use the camera; 100 meters above the night vision system should be selected 0.001 lux above the camera. Of course, with improved sensitivity, the camera will have a larger price increase.
Of course, and many other products, standard indicators of the phenomenon of virtual cameras is particularly serious. I have He holds a 0.1 lux camera and a nominal 0.0001 lux camera for comparison, which is actually better than the former. A lot of camera manufacturers, artificially increase signal strength, sensitivity is very good, but very poor signal to noise ratio, resulting in night-time image "snow point" A lot of great.
Distance issue:
100 individual products so there will be 100 infrared IR night vision distance standards. I think should still take the customer's application effect of the standard. What are the criteria customers? Is to see people! What the "visual distance", "found that distance" of these allegations are vague uncertain. Different grades of cameras, lenses match between infrared light for the same lamp light sensitivity may be issued by the difference many times, visual distance can also be far too small. Therefore, the infrared light of a lamp specifically defined as what is said is not very scientific meters. The role of an infrared light range, only with determining the quality of cameras and lenses in order to determine their role in the common matching distance. Moreover, because the application in different environments, the effect will be very different, it is best left a certain margin.
summary issue:
How far are able to do infrared night vision in the end? Technology, then home, 100 meters above the infrared night vision system is not difficult. Technology, home, referring to the infrared light must be proficient in technology, infrared sensor and infrared sensor technology, camera lens technology, the three are indispensable. Products on the market now, distance has been done for more than 500 meters, but cost is relatively high, civilian market is is rather restricted. Infrared night vision surveillance, there is a lot of common technical issues and problems, doubts, this paper took the opportunity to make a large number of readers and engineering companies to communicate at the same time hope for the project developers and users a better understanding of infrared night vision surveillance and provide valuable reference.
