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Network Webcams blog
Archive for the ‘IP Camera Glossary’ Category

Glossary: JPEG

December 1st, 2008 by James Drinkwater

A JPEG is a way of storing images on a digital device such as IP CCTV cameras, digital cameras and mobile phones. JPEG is a compressed format, giving a greatly reduced file size compared to image dimensions. The compression is adjustable but greater compression rations will result in loss of data and as such grainier pictures.

JPEG stands for Joint Photographic Experts Group, who created the format when trying to produce a smaller file size for transmitting images across the internet. Most IP CCTV cameras support this format due to the reduced file size which helps to reduce bandwidth and hardware usage.

Glossary: IP Camera Software Development Kit (SDK)

December 1st, 2008 by James Drinkwater

A Software Development Kit or SDK is a library of code used for creating applications, usually on specific platforms, to work with a specific IP camera, or range of IP cameras. With IP security cameras SDKs usually consist of code designed to access and retrieve images from a camera over the network, or to alter settings. SDKs are similar to Application Programming Interfaces (API) in that they allow remote communication with IP CCTV cameras, but SKDs differ in that they are created to allow camera-native communication to be embedded into proprietory applications.

Included with an SDK is full descriptive literature describing how the code works, how it should be used and often includes working examples to help developers understand how to integrate the code with their own. SDKs tend to cover an entire range of devices but may contain code chunks which are specific to one particular model.

Most IP camera SDKs are very tightly controlled by the manufacturer, often requiring registration and the signing of non-disclosure agreements to protect their software and intellectual property.

Glossary: Outdoor CCTV Surveillance

November 25th, 2008 by Greg

IP cameras can be installed in both indoor and outdoor locations giving you the flexibility to choose the right camera for your needs.

Outdoor IP cameras come in two distinct variations. They can either be suitable for outdoor use with the addition of an external enclosure (such as an Axis 214 or Panasonic BB-HCM580) or they can be placed outdoors with no additional protection (such as a Mobotix M22M-IT-D22 or Panasonic BL-C160).

External enclosures are normally rated against the ingression of solid matter such as dust, dirt etc. and against water penetration (rain, snow etc.). The rating is normally expressed as an IP number and the values attributed will give the overall protection rating of the enclosure. Most housings also come with fans and heaters and are thermostatically controlled to keep a reasonable ambient temperature so the camera view doesn’t steam up with condensation in colder climates.

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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.

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).

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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.

Glossary: Network Video Recorder (NVR)

October 20th, 2008 by Greg

Panasonic i-Pro WJ-ND400 Network Video RecorderA Network Video Recorder (NVR) is a digital device which sits on your IP CCTV network to recieve live image/video streams and record them digitally to a hard disk.

An alternative to PC/server-based recording, the NVR offers a less complex installation, is easier to set up and has a user-friendly interface for day-to-day use. As the NVR is solely designed for IP CCTV surveillance, the embedded operating system is optimised to handle the maximum number of cameras the unit supports. This means that you can be confident that the NVR will be reliable, stable and perform as intended, unlike a PC/server based approach which has many variables that could affect performance.

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Glossary: Bandwidth Limitation

October 2nd, 2008 by Kevin Bowyer

Bandwidth is an increasingly precious commodity both on your local network and across the wider Internet. Where IP video and CCTV cameras are concerned bandwidth is an important factor to consider when designing an IP CCTV system or looking to convert an obsolete analog CCTV system to IP CCTV.

Luckily, many IP cameras incorporate a facility to limit the amount of bandwidth used up by the camera at any one time. This allows those planning CCTV systems and networks incorporating IP CCTV to plan bandwidth usage with confidence.

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