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  Video Camera - Selection Guide
項目符號 Main
What is Video Camera
Typical Deployment
     - Traditional VCR
     - Network DVR


What is Video Camera

The starting point for any visual surveillance system must be the camera. The camera creates the picture by capturing image from real environment through its lens and image sensor, of which will be transmitted to the control position, such as control Center, Network DVR or CCTV system. Nowadays, there are may different camera design to suit different complex environment. For instance, Professional Video Camera for mission-critical surveillance purposes, Doom Video Camera for normal small-size retail stores, Convert Video Camera for monitoring in concealment.

Typical Video Camera composed by Lens, Image Sensor, Processing Unit and Output Device.

Lens: Just like photo camera, Lens play important role in all image capturing units in the world. It is used to gather the light from outside world, focalize and transmit them to Image Sensor. Therefore, there are many selection of Lens in the market, 2.8/4/6/8/12/16/25 mm Lens, Fixed/Manual/Auto/Zoom type Lens.
Image Sensor: After the gathering of light by Lens, those light are needed to create transmission signal to be any use. Image Sensor receive all the light coming in, and product electrical charge for the creation of a "Picture". The most commonly type of Image Sensor is CMOS. They are low in cost, however, produce poor-quality of picture especially dealing with our 3D complex real environment. CCD, is an alternative, produces high-quality picture and clear color distinctions.
Processing Unit: It is the main component of a typical Video Camera. It gathers all the pictures generated from Image Sensor, and produce transmittable signal to Output Device. Also, it controls the operation of Electric Shutter, BLC and AGC. [See more at "Functionality" part]
Output Device: Simple, it outputs all the signals to Center, Network DVR or CCTV System. The commonly using interface is BNC. The 'BNC' plug is for connecting the coaxial video cable. In practical use, Coaxial Cable connects with BNC Output unit and take signals to Recording Unit.  

Statistics point to major reductions in the amount of crime being committed where there are cameras installed. An article in 'New Scientist' magazine showed that simply installing a system can reduce crime, in the areas covered, by over 95%. As our customers inform us that they are having similar results in all types of business, you will begin to appreciate why Visual Surveillance System is seen by many as the best system for deterrent and detection.

We are sure that you would wish to avoid having to catch those who are perpetrating crime against your organization. Generally, once a Camera system is installed, it will only be fools who attempt to perpetrate offences within its field of view. These are often caught but for the majority it will provide a very high level of deterrence.

Typical Deployment

Traditional VCR

Method for recording video on tape with tape-recording equipment is an analog type. Namely, each camera connect to one device (Multiplexer) to split all the cameras’ image, and then output them on a CRT monitor, and use VHS to record the image on video tape. Operator then uses storage rack to protect tapes from humidity.

As the whole system involved many independent equipments, Multiplexer, TV, several VCRs, immense amount of tapes and expensive storage space that led to high running and operating costs.

Tapes would wear or tear over time, image would distort, video integrity is hard to preserve over time due to changing climate and humidity. This is an ever-present problem of analog tapes.

User may have to review all the tape to find one specific image. And large storage space is required for tapes. Spaces are noticeably expensive in some cities such as Hong Kong. Keeping records for a long period of time, such as one year, is impossible.

Systems need operator to change tape frequently and perform system maintenance, and operator must be at the site to acknowledge emergency.

All the records stored on tapes. Viewer must go to the site and take the tapes to see what was going on. When camera number has to be increased, that also led to the problem of cabling, and troublesome modification of the whole system.

All the problems stated above found no solutions until the boom of digital era. From cameras to digital cameras, from tapes to CD or Hard Disk, from CRT to LCD, surveillance system also gets the same change - VCRs to DVRs (Digital Video Recorder) . From 2002 to 2003, DVRs constitutes up to 75% of new CCTV systems in United States, especially after the terror attacks 9/11. With continuous product improvement come better-functioning products, lower costs, and a steadily growing customer base, products based on digital technology begins to dominate the entire CCTV market.

We now use CD to replace analog tapes, and all the captured images from cameras distribute over the Internet, user can monitor from anywhere at any time.

Network DVR
A Network DVR is a DVR linking CCTV cameras together, and records all signal to Hard Disk, but at the same time, provide remotely access from Internet or computer network to download, replays record, being controlled by remote user but without affecting normal daily operations.

Our DVR is TCP/IP based, that means:
Flexibility and Compatibility:
When every computer connects to the Internet, a unique IP address is allocated to the computer, IP addresses are used to locate computer locations in the world of Internet. When user's computer and the DVR are IP-based, they can communicate with each other and share information or resources.

Digitalization of Recording Technology
As the functionality, usage, quality and costs of VCR-based surveillance system no longer satisfy present surveillance needs and complex environment, that led to the development of DVR, namely digitalized VCRs. Since the introduction, DVRs are replacing traditional VCRs and sales are still increasing with each passing year.

Digital video surveillance is the latest trend and development in the security and surveillance industries. Customers are demanding more advanced surveillance systems for more secured and effective security monitoring. With advanced technologies and high speed data transmission, DVR system makes traditional Video Tape-Based monitoring and recording system obsolete.

As all the captured image is digitalized, the storage media were no longer dependent on tapes. Images are stored as computer files on computer Hard disk:


DVR System uses computer hard disk for data storage. Operator no longer change tapes frequently and hence save a lot of spaces. And the storage time is also significantly longer.

DVR system do not need Multiplexer, separate recorder or large storage space for tapes, this significantly reduce the operating costs.

DVR System uses computer hard disk for data storage. Operator no longer change tapes frequently and hence save a lot of spaces and labor. And the storage time is also significantly longer.

As all records are in digital format, user can easily back them up to CDRW, Floppy, or mobile rack. Also, user can replay records fast or slow forward, backward, frame by frame, zoom in or out, snapshot....etc

DVR is developed for replacing analog VCRs, all the standard are almost identical to VCRs. User can easily renew their system to DVR without technical works.

DVR provide multi-user login system, that enables system administrator to control access of other DVR operator, that ensure internal settings not being changed by third party.

However, a Digital Video Recorder (DVR), digitally records the video image so it provides clear image like a picture. It also has a function to record continuously so you don’t have to worry about the frequent change of tapes. With the easy distributed digital format, recorded images, video and audio are easily distributed and viewed at home desktops and notebook. DVR, therefore, is a video recording surveillance system for the next generation and it is growing very rapidly. By contrast, analog CCTV would be obsolete over time as digital technology takes over.

In dealing with small business, especially retail shops, showroom, offices, franchises, chain stores...etc Network DVR Technology is the excellent tool to satisfy their needs, as DVR operator is not essential to smooth daily operation of typical system.


For more information:
Video Camera Selection Guide - White Paper

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