Coşul este gol



DIPOL Weekly Review - TV and SAT TV, CCTV, WLAN
No. 3/2008 (Jan. 21, 2008)
Intelligent software as a condition for development of CCTV. In view of cheaper and cheaper video surveillance equipment (cameras, DVRs etc.), the barrier to progress in security systems based on video technology becomes an immense amount of the transmitted information that also has to be analyzed in the monitoring center. It requires growing network capacity and continuously increasing number of the staff. Thus the importance of automation of data analysis, possible due to IVS (Intelligent Video Software).
Hard work of computer programmers will allow to introduce in short time a number of automatic procedures:
  • Advanced Motion Detection - resistance to disturbances (change of light, various weather conditions, shadows, reflections etc),
  • Losing Detection - detection of left objects,
  • Motion Tracking - tracking of moving objects,
  • Facial Detection - recognition of people,
  • Vehicle Identification - identification of license plates,
  • Object Persistence - analyzing persons/objects that are a long time in the field of view,
  • Fire Detection,
  • People Counting,
  • Traffic Flow,
  • Action Analysis - scuffles etc,
  • Flow Control - of crowds of people (at stadiums etc),
  • Attention Control - analysis of the time that people spend observing an object (exhibitions, shop windows etc).
Quite another story is integration of CCTV monitoring with other security systems, e.g. biometric access control.
(based on: Liu Yi - China Public Security International)
Systems recognizing license plates are probably the most popular IVS application
Modular multiswitch installations. One of concepts ensuring flexible SMATV installations is division into independent modules processing different kinds of signals. The diagrams below illustrate distribution of terrestrial and two satellite signals (from two satellites). For the terrestrial path there are recommended channel amplifiers of ZG series. The satellite paths use multiswirtches of MS-553/554 , or MSR-5xx series, and QUATRO LNBs. The choice of the satellite is made by the user with the help of DiSEqC switch (in the apartment). Every apartment has to be connected to the branches from the three paths (modules). It is well to remember that many users may want to have access to at least two independent satellite signals (the owners of two receivers or popular PVRs). In practice, to every outlet in the apartment there have to be connected three cables.
The second diagram shows flexibility of modular solution - e.g. if some users do not need second satellite signal, some multiswitches can be omited.

Modular installation ensures maximum flexibility, allows to provide chosen signals to different parts of the apartment and configure the set of signals provided to individual outlets according to the needs of the residents. It is especially recommended when the people have different requirements. The costs can be divided proportionally to the real expenses on the implementation of different solutions.
Cascadable Multiswitch: Terra MS-553 (5-input, 4-output)Multiswitch: Terra MS-554 (5-in, 4-out)8-way Tap: Signal O-8-20dB (5-1000MHz)8-way Tap: Signal O-8-18dB (5-1000 MHz)75-ohm terminating resistor in F plug
The user has access to terrestrial broadcasts and satellite programs from Astra and Hotbird
Cascadable Multiswitch: Terra MS-553 (5-input, 4-output)Multiswitch: Terra MS-554 (5-in, 4-out)8-way Tap: Signal O-8-20dB (5-1000MHz)8-way Tap: Signal O-8-18dB (5-1000 MHz)75-ohm terminating resistor in F plug
The user can watch terrestrial TV and connect two independent signals from Hotbird (e.g. to double tuner PVR)
Active video transmitters. Doing a CCTV installation it is often convenient to use thin cables. Sometimes there are needed long cables, over 150 meters. In both cases we should use a UTP/FTP cable and video transformers. Applying the active transformers - TRN-1/400 (transmitter) M1668 and TRO-4/400 (receiver) M1670, we can transmit with typical 4-pair cable video signal and power the camera - up to 1600 meters.
The M1670 receiver has four inputs (4 channels).
Video signal and audio signal transmission via twisted-pair cable with power option (pdf) - description of devices (so far in Polish) and installation diagrams.
Color Day/Night Camera: Sunell SN-587C/A/10 SWD (w/o lens, mechanically switching IR filter)UTP Video Transmitter: TRN-1/400Color CCTV Monitor: QUANZ ZM-CR321NP (21UTP Video Receiver: TRO-4/400Digital Video Recorder: CPD-501 (4 channels, LAN)
Transmission of images from CCTV cameras over long distances via UTP/FTP cables
USB Control Unit (PTZ) for IP CCTV. The K9153 unit is a peripheral device used for control of pan-tilt-zoom IP cameras. The device is connected via USB port to a computer with NVR (Network Video Recorder) software installed - for managing the system and PTZ cameras, live monitoring, and recording.
The device is an equivalent of similar analog control units. It is equipped with 12 programmable keys which can control functions of any PTZ camera (e.g. zoom, pan or tilt action, or return to the previously defined position). Due to USB interface it is a Plug &Play device - Windows OS will automatically detect it and install proper drivers.
Installing the drivers provided by the manufacturer, the operator can control the system with mouse pointer. The K9153 control unit can cooperate with e.g. Alnet Netstation K3204, K3208, K3212, K3216, K3232, NUUO K3108, ACTi NVR 32 K3032, as well as free software for ACTi (NVR 16) and Pixord (P6032) cameras. Additionally, thanks to high quality and precision, the device can be employed by "professional" computer players as an advanced joystick.
USB Control Unit (PTZ)
USB control unit K9153
Cameras for public transport. Cameras and local video recording improve a lot security levels of urban transport. Usually in one car there are installed two or three cameras (depending on the length of the car). Due to the risk of "close encounters of the (...) kind" with some passengers, the cameras should be of vandal-proof construction, like M10744.
Vandal-proof dome camera in a bus in Birmingham
DVRs for network operation - two resolutions. Using DVRs with LAN interfaces we have remote monitoring option even in analog CCTV systems. It makes the surveillance much easier and allows to check efficiency of the system. Without physical presence at the place, the operator / managing person can estimate the threat and make the appropriate decisions.
In local networks there is no problem with video transmission. But in the case of Internet connectivity, the link should either have large capacity or the quality of transmitted video has to be adequately reduced. It is also important to use effective video compression.
The KPD video recorders have been specially prepared for network operation. The KPD-604PL M8504 (4 channels), KPD-608PL M85078 (8 channels), and KPD616PL M8616 (16 channels) enable the user to define two different resolutions. The first one, for local recording, is set for getting good quality of recorded material, whereas the second, lower resolution, is adjusted to the capacity of the link. An important feature of the KPD series is use of MPEG4 compression for video transmission. It allows to get better quality of the images than e.g. in popular CPD DVRs that use MJPEG compression.
MJPEG or MPEG-4 in IP CCTV cameras?
IP CCTV in VLANs. Security of IP CCTV system and high network efficiency are easier to maintain in VLAN (Virtual Local Area Network). VLAN is logically allocated computer network, from a larger physical network. It is a group of hosts that communicate as if they were connected to the same Ethernet cable, regardless of their physical location. To create such networks there are used manageable / configurable switches allowing to group ports and block communication inside the groups and among them. The networks can be based on several such switches.
MPEG-4 IP Camera: ACTI CAM-5321 (Day/Night)MPEG-4 IP Camera: ACTI CAM-5321 (Day/Night)MPEG-4 IP Camera: ACTI CAM-5321 (Day/Night)MPEG-4 IP Camera: ACTI CAM-5321 (Day/Night)
IP cameras, the recording server, and operator's computer are grouped into one VLAN, and the rest of the devices - into a second VLAN. The regular users cannot access CCTV resources.
RF connectors - attenuation and maximum frequency. Maximum frequency of a connector is determined by its construction and workmanship (materials, precision, compliance with standards). The table below shows the limit frequencies for various connectors used in antenna systems.
Another important parameter of RF connector is attenuation. Apart from mismatch loss (characterized by VSWR) it includes the losses in the dielectric and conductor. Generally, the attenuation coefficient is between several thousandths and several hundredths of a decibel.
Similarly to VSWR, the losses are specified for certain frequency / frequencies or given in the form of characteristics. For example, BNC connector attenuates a 3 GHz signal by 0.2 dB. Microwave connectors, e.g. SMA, are described in this aspect by the functional 0.06*SQRT(f[GHz]), e.g. at 4 GHz the attenuation of SMA connector is 0.06*2 = 0.12 dB. The testing frequency is 6 GHz.


Limit frequency [GHz]






































LAN with wireless connectivity to the Internet. There are many cases when several LANs (e.g. in office and warehouses, in several houses etc.) should be grouped into one network with Internet connectivity. A convenient solution is provided by use of access points (APs) working in WDS mode. This mode of work eliminates support of wireless client cards and APs using AP client mode, which improves integrity and security of the network.

WA-2204C N2647 can support even eight WDS nodes. Using as the router e.g. TL-R860 N2990, it is possible to allow / deny access to the Internet for individual users identified by MAC addresses, as well as to filter URL addresses and protect the network behind the firewall.
Router TP-Link TL-R860 (8 LAN / 1 WAN ports)Access Point: WA2204C (AP/APC 54Mbps)Access Point: WA2204C (AP/APC 54Mbps)Access Point: WA2204C (AP/APC 54Mbps)Access Point: WA2204C (AP/APC 54Mbps)
We have written about:

MIG-29 - 3,5" service LCD monitor - useful device for CCTV installer. Service monitor MIG-29 M3104 is a very handy device for anyone installing and configuring CCTV systems...
- archive DWR of Oct. 12, 2007

Size of an object on monitor screen. According to EN 50132-7 norm, the size of the representation of an object, e.g. human figure should be strictly connected with the aim of the operator - identification, recognition, detection or general observation...
- archive DWR of Nov. 26, 2007

The principles of designing terrestrial TV installation. The diagram below shows example installation in a building. The table contains signal levels for three chosen outlets of the installation...
- archive DWR of Oct. 29, 2007

Index of published issues.
Marathon housings are CE, IP, RoHS compliant.
George Popescu
Consiliere clienţi
Dacă doriţi să primiţi Săptămânalul Dipol prin email, introduceţi adresa:
Nou în bibliotecă
Regulamentul | Reclamaţii | Download | Cookies | SitemapToate drepturile rezervate © 1996-2016 DIPOL sp.j.