Common Video Surveillance Interference and Ways to Deal With

When video transmission, there are often some malfunction, such as without images, video stream not smoothly, monitor screen interference, etc. In the article, there will list five common monitor screen interference and also tell you how to deal with them.

First, interference with horizontal line

The most common fault phenomenon displays on the monitor screen: black or white horizontal line scrolling up or down slowly. Then, when analysis of such symptoms, it needs distinguish two different causes of failure. There are two factors: power supply or earth loop problems. The easy way to distinguish problem is that in the control panel, getting the nearest camera output signal with good power supply. If there is no interference with the horizontal line, the control panel is OK. Next, get an available potable monitor connected to one camera’s video output terminal, and check each camera individually. If there is interference, then processes. If no, the interference is caused by earth loops or other reasons.

Second, grainy interference

When monitor displays slight grainy interference, the normal image will not be drowned. While serious, the image can not be watched (even destroy synchronization). The reasons for this failure phenomenon are more complex. Generally, there are some reasons:

A, The quality of video transmission is not good, especially poor shielding properties (shield wire is not good quality copper wire, or shield wire is too shin to shield.) Also, line resistance of this video wire is larger; the greater attenuation of signal is also one of the reasons for aggravated fault. In addition, the Characteristic Impedance of this video cable not 75Ω or beyond the prescribed parameters of 75Ω is also one of the reasons for failure. As the failure caused by bad video cable is uncertain of the reason for the grainy interference phenomenon, we should be careful to decide the cause of phenomenon. Only after we exclude other possible, we can consider problem from bad video cable. If it is the cable quality problem, the best way to solve of course is to replace all the cable with required cable.

B, Grainy interference is caused by “not clean” power supply. The named “not clean” power supply means that there is superimposed interfering signal (50Hz sine wave) on the normal power supply. Such interfering signal of power supply often comes from devices used SCR in current grid, especially SCR devices with high current and high voltage. For example, if there are high-power SCR FM speeders, SCR rectifying devices and SCR RF conversion devices, etc. all of these devices will generate pollution. The solution is relatively simple, just opting purification power supply or online UPS supplying power for the entire system.

C, There is strong interference source near the system. This can be judged by investigation. If this is the reason, to solve problem by strengthening he shield of camera and ground connection the pipeline of video cable.

Third, wavy interference

The wavy interference causes by failure of short circuit between the core wire of video cable and shielded wire. When there are deeper and messier large wavy interference, the image will be completely destroyed and won’t form an image and synchronization signals. This always happens at the BNC connectors or other types of video connectors. Therefore, every signal of the whole system won’t get problem, but those channels with bad connectors. Just check these joints one by one, problem can be resolved.

Fourth, vertical stripe interference

The fault phenomenon of vertical stripe interference causes from mismatch characteristic impedance of the transmission wire. There are several pieces of equally spaced vertical stripe interference on the monitor screen. The frequency of the interference signal is basically an integer of the line frequency, which is due to the characteristic impedance of video transmission cable not 75Ω and caused impedance mismatched. The solutions often rely on “the top series resistance” or “the terminal parallel resistance”. In addition, it is worth noting that, when the video transmission distance is very short (less than 150m), there will not be the above interference if opting video cable with impedance mismatched and larger distribution parameters. Then, the fundamental solution is to ensure the quality of purchased video cable and to do sampling inspection for the cable.

Five, other interference
There is space radiation interference introduced by the transmission wire. Such interference phenomenon mostly caused by the stronger, higher frequency space radiation source near the transmission system, system front-end or central control room. One of the solutions for such case is to learn the surrounding environment of the system created, and to try to avoid or be away from the radiation source. The other way is to strengthen shielding of the front-end and central equipment, or opt for steel pipes and ground connection for the pipeline of transmission wire, if there is no way to avoid radiation source.


The above are some common interference happened on the screen of video monitor. Do you know all the phenomenon and how to solve the related cases? Well, it is not hard! Welcome your kindly comments!

How to Pick Home Monitoring Device? There are Tricks to Select Quickly!

During the recent two years, home surveillance industry is very hot. The status that the generation after 80s are willing to accept new things and most of them have been parents, have accelerated the development of this industry. It also reflects that the modern emphasis on security. The joint of traditional security manufacturers and IT vendors promotes the development of home monitoring and smart home. But facing complex products, how do consumers in the end choose the most suitable home monitoring equipment?

Is Dual Camera helpful?

We must define our needs when buying home monitoring. And now some home monitoring devices are equipped with two cameras front and rear. Some products’ post cameras are just used for scanning the two-dimensional code to download and install client software to phone. And there are no more functions during common usage. This will not only increase the cost of purchase, low the utilization, so it is not recommended to buy this slick configuration.

It is necessary to have PTZ rotation!

To place device at home, we need confirm a problem that whether there requires PTZ rotation function. If no PTZ, the device just can monitor one position. Device with PTZ can control the rotation of the device through computer and the mobile client software. This can reach the area needed to view the video surveillance. From convenient and intelligent perspective, it is necessary to select device with PTZ rotation. But to choose 180 degrees or 355 degrees depends entirely on the demand of purchase.

Voice intercom plays a role of loud hailers.

Voice intercom function depends on personal preference. I personally still prefer this feature. If baby is at home, parents can still dialogue with baby at lunch time through this function. Also, if there encounters unexpected situations, the device can also play a role of loud hailers by voice intercom, thereby preventing further deterioration of the matter.

Night vision function extends the working hours.

Some home monitoring devices now have not night vision function. That is, the monitoring products become "illiteracy" at night without surveillance function. Surveillance device should also have night vision capabilities. When choose the function, we need to look at the parameters of low illumination. That is to say, at much of the low illumination, the device can continue to work.

Because device is used in the home, the aesthetics can not be ignored when choose product. It should be consistent with the overall home decor. There are also wide dynamic (WDR), strong light inhibition, etc. functions, which are chosen according to the needs of the users and our budget and the frequencies of function usage. It will be not necessary if we do not use some function, also the cost effective of products will be reduced.

What are the Difference & Advantage between Array Camera and Infrared Camera?

Array camera is one of the infrared cameras. A common infrared camera is composed of many LED lights, but array camera has less than 10 lights. Then what are the differences between array infrared camera and common infrared camera, and also the advantage?

Advantages of array infrared camera compared with common infrared camera

Pros one: Long life.

Array infrared technology ensures CCD good working condition, and its usage life is nine times the life of common LED infrared cameras. As the ordinary LED infrared camera places LED light tube and camera in the same cavity, the heat from LED tube can not be disseminated effectively through PCB. The temperature problem restricts the usage life of CCD severely.

 

Pros two: High efficiency.

Semiconductor light-emitting efficiency and thermal performance is benign cycle. The better thermal performance, the lower operation temperature, then better protect luminous efficiency. On the contrary, it is stuck in vicious cycle of constant decay in efficiency.

Pros three: High brightness.

The higher brightness is, the longer light shining distance. A single LED output optical power is 5~15mW. Of course, we can increase the brightness via adding current progress. But with the limitation of material itself, infrared photoelectric conversion efficiency is not high only 20 of the light, the remaining 80 is the heat. In addition, multiple LED lights are carried on PCB board with poor thermal performance. Dozens of high efficiency and high power epistar packages on a plane and configure good thermal device. The light source of array infrared camera has brightness more than 100 times that of a single LED.

Pros four: Even light.

When multiple infrared LED rounds the camera lens, brightness of the stack part will be particularly high, and also composed of one circle. But the array infrared camera is just a quite big point light source. Through special optical imagination, the light shines monitored object evenly, the brightness between the monitor screen of intermediate and round is uniform.

Pros five: Small size.

Array infrared camera opts for highly integrated advanced packaging technology. An array infrared chip packaged dozens of wafer, assuming that dozens of infrared light source consisting with single LED installs on high speed dome camera, the effect can be imagined.

All the advantages of array infrared camera compared with common infrared camera are the above five points. They are long life, high efficiency, high brightness, even light, small size. In summary, the market is mainly oriented to the array camera; infrared camera will be eliminated gradually.