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Network Webcams blog
Archive for 2008

Glossary: Interlaced Scan

November 24th, 2008 by James Drinkwater

Interlacing is a way used by IP camera manufacturers to speed up the refresh rate of their cameras.

An IP camera sensor is made up of a mesh of pixels. The colour value of each pixel is transferred to the computer as a series of numbers which the computer then interprets back into colours and outputs on your screen. However, in particular with megapixel cameras, there can be millions of pixels to retrieve, which can require a large amount of processor time, either slowing the camera down, or pushing the price up as more powerful processors need to be used.

Since IP cameras take many pictures per second, the time between images is very small, leaving very little time for objects to move significantly. With this in mind, interlacing was developed whereby instead of reading each line of pixels one after another, only every second line is read. On the first pass the camera will read lines 1, 3, 5, 7 and so on. Once the last line has been read, the camera returns and reads lines 2, 4, 6, 8 etc, meaning that each frame only half the image is read, saving time and bandwdth. This means the camera can achieve a greater frame rate without requiring more powerful hardware.

The downside with this is that since objects are moving between shots, the position of the objects in view will change between shots. With slow moving objects this is fine, but with fast moving objects such as cars or people, a tearing effect occurs along the edges of the object.

Two images one with progressive scan where a face can be seen, the other is a blur

The image on the left is from a progressive scan camera, the image on the right is from an interlaced scan camera. As you can see, the difference with moving images is huge.

Glossary: Pixel

November 24th, 2008 by James Drinkwater

Pixel is short for picture element and is the term used for each of the small dots of colour on a computer screen which make up a picture. It also refers to the small receivers on IP camera sensors which transfer the light recieved into data.

Each pixel has a colour value of red, green and blue. Varying the values of these three colours will alter the overall colour of the pixel. With IP cameras, the sensor records the red, green and blue values for each of these pixels and then transmits the values to your computer, which then rebuilds them in an image on your screen.

Axis Increases Its Global Market Share

November 21st, 2008 by Kevin Bowyer

Axis have just announced that they have increased their global market share from 32% to 33.5%.

The data comes from IMS Research’s latest report on the state of the CCTV and Video Surveillance market and covers sales in 2007.

Network Webcams supplies Axis CCTV equipment in both direct sales and CCTV system installation capacities.

ONVIF – Setting the Standards in IP Video. We Hope.

November 4th, 2008 by Kevin Bowyer

Onvif logoIt’s been a long time coming but ONVIF, the IP Video standards-setting collaboration between Axis, Bosch and Sony, is finally running and available to join. We’ll be following and, hopefully, contributing to the project and we fully support the standardisation of network video.


Axis treats us to better image quality by replacing the lens in their Axis 211M IP cameras

November 3rd, 2008 by Greg

Axis 211M static megapixel IP camera with new Tamron megapixel lensAxis recently announced they have started to ship an alternative lens with their Axis 211M megapixel IP camera. The new lens is by Tamron and is a designed specifically for megapixel use.

The specification of the lens is almost identical to the previous one: CS-mount, 3.0-8.0mm, vari-focal, DC-iris, F1.0, horizontal viewing angle: 37 degrees (tele) – 90 degrees (wide) and the lens itself it slightly longer by about 15mm but should still fit any any standard outdoor enclosure.


Videotec launches PoE compatible housing for outdoor IP CCTV installations

October 30th, 2008 by Frank Crouwel

Videotec Verso Hi-PoE external IP CCTV housing
Videotec has launched a Hi-PoE camera housing ideal for outdoor installation of IP network cameras. Installing CCTV cameras in external locations has never been easier. Now, you only have to run a data cable to the camera, there is no longer a need for additional external power cabling for the housing. This makes IP CCTV installations more flexible and much more cost-effective.

PoE technology gives IP CCTV a huge benefit over traditional CCTV. The PoE housing will soon be available in the UK. Keep an eye on our UK IP CCTV camera store.

Axis reports continued strong growth in network CCTV

October 27th, 2008 by Frank Crouwel

Axis interim report (January to September 2008) shows continued growth within the area of network video. The sales increase amounted to 35 percent compared with the same period last year. Sales within IP Video totaled SEK 522m (approx £44m) during the third quarter July to September, corresponding to growth of 32 percent.
“There is considerable interest in all regions for network video products in security installations… Axis’ expansion plans remain,” Ray Mauritsson, CEO of Axis, said in the report.
Axis reports that the Americas and Asia displayed strong growth figures, while the third quarter was characterised by a degree of caution and project changes within EMEA.

Axis reports that 116 new staff were employed during the first nine months of 2008.

Axis is the worldwide leader in network video products used within IP CCTV and security applications. Network Webcams is an Axis Development Partner (ADP) as well as an Axis Solutions Gold partner, offering the full range of Axis network video products and developed applications.

Glossary: Wireless IP Camera

October 24th, 2008 by Greg

There are IP cameras available today which have wireless connectivity built-in as standard allowing them to be placed around the home without the complication of running Ethernet cable to each room.  Other IP cameras also offer wireless connectivity as an additional add-on such as a wireless card.  These cameras can be placed around your home or business to provide IP CCTV monitoring across your wireless network (WLAN).


Glossary: Tampering Alarm

October 24th, 2008 by Greg

The Tampering Alarm is an intelligent feature found on IP CCTV cameras which have a strong focus on security, such as tamper/vandal resistant IP cameras. The kind of cameras which are designed to be installed in exposed locations where there is a active threat of people interfering with it.

It’s easy to set up. Once activated the camera will notify you if it has been moved, obscured, covered or sprayed with paint.

They way it works is simple. When the camera is first turned on it will take a few seconds to examine the scene. After the examination process is complete the scene is locked and any alteration to the scene can cause an alert. This does mean however that if the light changes drastically in a scene (such as turning a off a light) then the camera will generate a tampering alert. Some cameras have the facility to ‘turn off alerts from dark images’ so that it isn’t affected by light changes but the downside of that is it will no longer trigger an alarm if the camera is covered or sprayed, only if it has been moved.

Tampering Alarms are a useful tool which provide instant feedback when a camera has been compromised, something which could take a CCTV operator a lot longer to discover.

Glossary: Network Video

October 22nd, 2008 by Greg

Network Video, when used in security surveillance applications (IP CCTV), refers to a system which allows live motion video to be broadcast over IP-based networks, such as a Local Area Network (LAN) or the Internet, for the purposes of live monitoring or recording.

Network video uses a computer network as the means of transporting video and audio data rather than the traditional point-to-point cabling you would associate with analogue CCTV. This allows your digitized video and audio streams to pass through the same Ethernet cables which may already will be run throughout your organisation and business.

Furthermore, because network video is digitized to travel along IP based networks it can be viewed remotely from any computer in the world which has access to the Internet. This allows 24 hour surveillance of your property or business. Being purely digital also means the data is stored digitally and will retain its quality, color and will not be degrade over time in the same way as analogue recordings.