Bosch Sicherheitssysteme: affordable high-quality CC TV. Networked CCTV cameras capable of high quality images – live and recorded, moving and still – at an affordable cost, look set to increase public confidence in CCTV and reduce crime figures.

Recent advances in technology mean affordable security cameras can now deliver CCTV surveillance images of DVD quality. Cameras from Bosch Security Systems, for example, can cope with widely varying light conditions, can be easily connected to a network, and enable both video and still images to be viewed and recorded. Despite all these benefits, the security industry must hope that public confidence in security CCTV has not declined in 2007, following global TV and newspaper reports of a number of high-profile crime investigations.

Media coverage following these incidents reported the poor quality of images from a CCTV security system in each case. In addition, public confidence in CCTV as a deterrent and investigative tool cannot be helped when many CCTV clips shown in police and crime documentaries on TV programmes are generally of very poor quality – the standard of PC webcam images, rather than the clear, crisp images the public is accustomed to seeing on living room TV sets.

So why is there a difference between what is perceived and what is possible?

Innovative Imaging Technology

Provides Clarity Early CCTV security cameras, like most cheap webcams today, produce images using CMOS, which results in substandard image quality and poor light sensitivity. By contrast, high-quality cameras use a CCD (Charged Couple Device) chip. This is used in the Bosch Flexidome IP camera to provide images of astonishing quality at an affordable price. This ultra-compact and vandal-resistant camera provides DVD-like quality video at up to 25 and 30 images per second (for PAL and NTSC respectively) at 4CIF true resolution.

It is designed to ensure the highest possible image quality at all times, even under poor light conditions. Digitised video signals are sent over IP networks (LAN, WAN or Ethernet) and can be received and displayed on a PC web browser, viewed and recorded using the Dibos hybrid recording system, or managed as part of a VIDOS or BVMS video management system.

Compression Modes for High Image Quality

The quality of the image depends not only on the CCD sensing chip but also the compression technologies used to code the system for transmission. Video compression is necessary to reduce the quantity of data used to represent video images. It operates on the premise that much of the data present before compression is not necessary for achieving good perceptual quality.

Compression standards are set by MPEG (Moving Picture Experts Group), an ISO/IEC working group established in 1988 to develop standards for digital audio and video formats. The MPEG family of standards is used for coding audio-visual information (e.g., movies, video, music) in a digital compressed format. MPEG has several standardised compression formats, of which MPEG-4 is eminently suitable for CCTV.

A second ISO/IEC working group, JPEG (Joint Photographic Experts Group), established in 1986, works to build standards for continuous tone image coding photographic images. Its standards are widely applied in photography. Image files employing JPEG compression are commonly called ‘JPEG files’. The most common file extension for this format is .jpg.

To deliver high-performance colour pictures for viewing and recording, FlexiDome IP cameras use both the standard MPEG-4 and JPEG compression modes, as well as using bandwidth throttling and multicasting capabilities to manage bandwidth and storage requirements efficiently. These ensure that camera delivers the best possible image quality and resolution for each user’s network.

The FlexiDome MPEG-4 encoder creates high-quality streaming video at low bit rates, minimizing bandwidth and storage requirements, which further reduces operational costs. The camera combines 15-bit digital video processing (DSP), which enhances sensitivity, and Bosch’s XF-Dynamic feature, which extends the dynamic range, to provide a sharper, more detailed image with outstanding accuracy in colour reproduction.

Tri-streaming Optimises Live Video

Flexidome IP cameras can generate two separate MPEG-4 video streams and one JPEG stream simultaneously, while giving access to five users at a time. This advanced tri-streaming capability, not typically found in other IP CCTV systems, enables the user to optimise live viewing and recording requirements to meet specific site and enterprise needs. For example, Bosch Video-over-IP Systems (BVIP) can be configured to record video at one quality setting, while simultaneously providing live images at the best possible image quality.

Alternatively, the system delivers a high-bandwidth, MPEG-4 stream to a local LAN user, while simultaneously streaming a low-bandwidth MPEG- 4 stream to a remote user over a WAN connection, as well as using the JPEG stream for remote viewing, for instance, on a PDA. The analogue monitoring video output and on-screen displays (OSD) simplify focus adjustment and network configuration, leading to lower installation and support costs.

Day/Night Mode for Security in All Light Conditions

Security cameras often have to cope with bright sunlight at one extreme and low levels of night lighting at the other. Yet all users of security CCTV systems wish to ensure image performance – and therefore security – is not compromised under all light conditions. Flexidome IP cameras can operate in two modes, day and night.

In Night Mode, it provides enhanced night viewing by increasing sensitivity to infra-red (IR) light, using a mechanical filter. The IR filter can switch automatically from colour to monochrome by sensing the illumination level, or it can be switched remotely via a web browser. An internal, through-the-lens IR detector enhances monochrome mode stability by preventing the camera from returning to the colour mode when IR illumination is dominant.

The highly accurate 15-bit digital signal is processed automatically to reveal every detail of the image in both the highlight and low-light areas of the scene simultaneously. It reveals details that other cameras miss in ultra-highcontrast scenes. The cameras provide a choice of Bosch Dinion or Dinion camera technology.

Dinion technology meets the needs of most applications, while Dinion achieves very high picture performance under even the most difficult light and scene conditions. A Dinion camera can process an image with 15-bit accuracy, whereas most digital CCTV cameras use 10-bit processing or less.

It can therefore provide an image 32 times better than standard 10-bit cameras – a standard only previously possible with expensive, professional broadcast cameras. It results in images which are more vivid and true-to-life than any other CCTV camera. By revealing clear details such as faces, license plate numbers, it helps security managers provide better, more efficient security.

Contact:

Bosch Sicherheitssysteme GmbH,
Ottobrunn, Germany
Tel.: +49 0800 7000 444
info@service@bosch.de
www.boschsecurity.de