DIPOL Weekly Review

Megapixel revolution in CCTV. Development of IP CCTV technology has been relatively slow to date. An important reason was that DVRs with network functions (sometimes more advanced than those of some IP cameras) supported by low-cost analog cameras were an attractive alternative to IP CCTV systems.
But the limit of analog CCTV (PAL, NTSC) is resolution of the images (PAL: 720 x 576). Such restrictions do not exist in the IP CCTV systems equipped with megapixel cameras.
An analysis of the advantages of megapixel cameras can be carried out assuming that the optimum monitoring requires approximately 130 pixels per one meter of the observed object. For a 50-meter wide scene, an analog system (720 pixels) would require to employ 9 cameras. In the case of a camera with 1.3 Mpix resolution (1280 x 1024), the number can be reduced to 5 such cameras, for a 2 Mpix camera - only 4 cameras will do the same job.
A smaller number of cameras has other advantages. First of all, it lowers the cost and time of installation and maintenance. It also lowers operational costs - it is easier to conduct surveillance with a smaller number of points.
Of course, there is another alternative for megapixel cameras - very popular speed dome/PTZ cameras. With adequate lens, it is even possible to cover the area mentioned above with a single PTZ camera. However, such a solution has many drawbacks. First of all, the camera can be set only in one of two ways. The first one provides an overall view, without possibility of recognition of some important details, e.g. the license number of a car. The second way, using optical zoom, increases the capability of identifying details, but at the expense of losing the rest of the scene.
In addition, PTZ camera has to be controlled by the operator, who must decide what is interesting at the moment and focus on that area. In the case of fixed megapixel cameras, there is always available a complete picture, with all events recorded by the system. Due to a very high resolution of the cameras, the details can be viewed using digital zoom.

Megapixel video surveillance in practice

A picture from a megapixel camera with Tokina 185^o lens (M2236). Megapixel cameras with wide-angle lens will dominate city surveillance systems.

Multiswitch - what's inside? Multiswitch is an electronic device allowing to connect any output to any input (independently, each carrying different set of satellite signals). Simply, it is a kind of switch operating in the range of 950 to 2150 MHz.
In addition, it usually enables connection of terrestrial TV signals (46 to 862 MHz) or similar signals distributed by a cable TV network. The separation of the two kinds of the signals is carried out in the subscriber outlet.
For the satellite receiver used by a subscriber, the multiswitch is seen as an LNB which provides a set of signals of the required combination of band and polarization.
This means that multiswitches have to provide simultaneous and independent access to the bands and polarizations. Since there are two bands (Low: 10.700 - 11.700 MHz, and High:11.700 - 12.750 MHz) and two polarizations (Vertical and Horizontal), they have 4 (one satellite) or 8 (two satellites) SAT IF inputs. Typically, they are also equipped with the mentioned above input for distribution of terrestrial broadcasts - it makes 5 inputs in multiswitches used for one satellite, and 9 inputs in those receiving signals from two satellites. The control system of a multiswitch receives 14/18 V and 0 / 22 kHz commands (the same that control a full band LNB) and connects adequate input of the multiswitch, according to the voltage level (14/18 V - vertical and horizontal polarization) and 0 / 22 kHz signal (low and high band), with the corresponding output.

1 - 4-out splitter
2 - TV/SAT diplexer
3 - SAT TV receivers
4 - Control system
5 - Tap

Bands and polarizations in LNBs and multiswitches. Typical labels allow to connect properly the outputs of Quatro LNB and inputs of the multiswitch:

LNB:

• Low band (Low 10 700 MHz - 11 700 MHz):
  
- Vertical polarization - V/L
- Horizontal polarization - H/L
• High band (High 11 700 - 12 750 MHz):
  
- Vertical polarization - V/H
- Horizontal polarization - H/H

Multiswitch:

• Low band (Low 10 700 MHz - 11 700 MHz):
  
- Vertical polarization - V/Lo or 14V/0kHz
- Horizontal polarization - H/Lo or 18V/0kHz
• High band (High 11 700 - 12 750 MHz):
  
- Vertical polarization - V/Hi or 14V/22kHz
- Horizontal polarization - H/Hi or 18V/22kHz

Typical markings of the connectors of Quatro LNBs and multiswitches

ULTIMAX - DVRs for demanding customers - firmware update. When choosing a digital recorder it is important to pay attention to the possibility of software updates. Changing the firmware, the user gets new features, new languages, etc. Upgrading often allows to remove bugs from previous versions.
A large number of DVRs enables updating only via USB interface or a DVD drive. These both cases require visit of the installer or transport to a service center. Modern DVRs allow to update their software over the network. This solution eliminates the transport costs and saves time.
ULTIMAX DVRs enable remote firmware upgrade as well as transfer of current configuration settings.

Remote configuration window of ULTIMAX DVRs

Monitoring of a chain of shops. In distributed CCTV systems it is important to have continuous access to the images, and high reliability of recording all events. The systems should be able to record the images locally and stream them to the required remote locations via the global network (dual streaming).
The device that satisfies these conditions is PiXORD P4504 K2132, which is a video server capable of local recording on a hard drive.
The device can cooperate with four analog CCTV cameras. The video stream, compressed in MPEG-4 format, can be transmitted to the monitoring center and made available via the Internet. The local recording of the stream allows to protect the data in case of transmission problems.
At the monitoring center the images can be viewed with the help of NUUO software. The software also enables the users to record the video from the cameras connected to remote video servers and control of PTZ cameras (if such cameras are connected to the servers).

IP CCTV devices from PIXORD

A block diagram for a single location

A distributed system enabling remote surveillance in the monitoring center and local recording in branches, chain of shops etc.

Image detail in video surveillance. Probably everyone who deals with monitoring is interested in the issue of viewing angle and image detail. Or, how large area can be observed with one camera and how many details can be recognized.
First of all, it depends on the resolution of the camera. Resolution, usually given in pixels/Megapixels (Mpix) describes the number of the smallest elements of the image. IP CCTV cameras can be divided into devices with standard resolution, e.g. K1132, with increased resolution (1.3 Mpix, e.g. K1512), and with high/very high resolutions, e.g. K1412, K1422, K1433.
The second decisive component is the lens used with the camera. It determines the viewing angle (or the width of the scene) and also strongly influences the overall quality and deformation level. There is a special group of lenses with increased quality, designed for use with megapixel cameras. These megapixel lenses include e.g. M2236 lens with focal length of 1.4 mm (viewing angle 185^o) and M2235, with focal length adjustable from 4.5 to 13 mm.
Below there are fragments of images from an area monitored at different resolutions. There are three practically defined accuracy levels:

The table below shows the width of an area monitored with a megapixel camera, with the set image detail.

Megapixel cameras

 

Resolution [Mpix]	Pixels		Length/width of the monitored area (with required accuracy level)  [m]
	horizontally	vertically	rough	optimal	detailed
0.4	720	576	12	6	3
1.3	1280	1024	19	10	5
2	1600	1200	24	12	6
3	2048	1536	31	15	8
5	2560	1920	39	19	10

 

What WLAN antennas should be used in buildings? Deployment of antennas and access points (APs) in a building is often a matter of trying and error, to get experimentally the best results. Typically, a single AP is installed somewhere in the middle of the building.
Due to the need to cover the entire floor of the building, the antenna used should radiate in all directions. This condition is usually fulfilled by the typical bar antennas included with APs.
Very often, if the building is large and the antenna does not provide full coverage, some users try to use an antenna with a higher gain. The problem is that the effect can be just opposite. Antennas with a higher gain have more directional characteristics, resulting in improvement of transmission in the main direction and deterioration in other directions. Therefore, the only other antennas which can be used in buildings for improving transmission parameters inside buildings are omnidirectional devices. Such an antenna provides good results on one floor, but usually does not solve the problems on other stories, even the neighboring ones. Generally, each floor has to be equipped with a separate AP, each located in the way assuring the longest possible distances from one another.
For such installations operating at 2.4 GHz we recommend the indoor antennas TP-Link TL-ANT2405C A72713 (with 5 dBi gain). In the case of thicker walls and larger spaces, better results will be achieved by using the antennas ProEter A72621, with 10 dB gain and half-power beam of 23 degrees (vertical plane). The both types of antennas work with vertical polarization.

Example deployment of APs in large office block with reinforced concrete ceilings and the optimal shapes of antennas' characteristics

Resetting Access Points of TP-LINK.
It happens that the user has to restore default settings. The simplest way is using adequate button usually placed on the rear side of the device.

The resetting procedure consists of four steps:

• switching off the power (pulling out the DC plug),
• pressing down the Reset button,
• connecting the power,
• releasing the Reset button 10 seconds after the moment of power on

After a while the device will operate at factory default settings.

SAT Krak, October 16-18, 2008 - the trade fair is changing its face. A few years ago a trip to the fair was the fastest form of contact with recent innovations. At large fairs companies mainly promoted their new products. But today, this function has lost its significance. Greater importance is placed on the possibility of personal contact in one place with leading suppliers and the possibility of trade negotiations. It is increasingly important for the visitors to take part in training courses and conferences organized during the fair.

At the SAT Krak exhibition, the staff of the Marketing Department of DIPOL invites everyone to cooperation, price negotiations, training courses. The guideline of DIPOL exposition at SatKrak 2008 exhibition is "Multimedia home" - we will focus on the components of satellite systems.

Training courses and conferences at SAT Krak
DIPOL stand

DIPOL e-Store - modern business platform. Modern business is based on modern media ensuring quick response, thus many companies value the up-to-date solutions implemented in DIPOL e-Store: on-line confirmation of the availability of an item, access to wholesale prices (for logged-in users), shipping costs information, possibility of placing complex orders directly in the shipping department.

We invite the companies dealing with TV, SAT TV, CCTV, and WLAN equipment to register in e-Store.

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