2013 buying guidance on cctv surveillance system

Since the equipment for cctv video surveillance equipment has undergone changes during the evolution of the technology including compact size of cameras, and improved performance of image sensor, as well as video recorder and more, thus we write an update guide to you on how to buy these equipment on the basis of usage and requirements.

CMOS image sensors: Cost-effective, and low light sensitivity and low quality images with noise for analogue camera. (CMOS image sensor mainly used in IP cameras for megapixel resolution image capturing. )

CCD image sensors: High light sensitivity and high quality images with low noise. Compared to CMOS, CCD with advantage of clear images at low light condition or with infrared light. Herein we will focus on security camera with CCD image sensor.

Camera with CCD image sensor

The size of image sensor: Normally 1/4 inch, 1/3 inch or 1/2 inch. Typically, the larger of the image size, the higher quality of the image can produce and more higher on price.

Lens: Lens is core component for security cameras, it’s the “eye” for the camera, choosing appropriate lens is essential when consider a security camera. Lens with two major functions; firstly determine the field of view on image capturing-this is a function of focal length. Secondly, control the amount of light reaching to the image sensor-this is a function of the iris. The focal length can be fixed or vari-focal (eg. A lens can zoom and focus). The iris can be set manually or adjust automatically, then…How do we know which one is the best lens for camera ? How to choose camera with ideal focal length? 

Fixed lens are the simple type of lens, widely used in security camera with advantage of less expensive. The preset focal length requires a precise calculation for selection of lens, thus best suitable for the monitoring scene. The size of lens should be on the basis of the view area and its distance from the camera. The field of view of lens can range from a narrow 30°, which allow more detail at a given distance to a larger approximately field of view of 90°, which was known as a wide view angle.

Vari-focal lens: vari-focal lens offer more flexibility, allowing manually adjustment on the field of view. Compared to fixed lens, it’s slightly more expensive, vari-focal lens are very popular because it allow user to get a more accurate of field  of view for different monitoring scene. Most widely used vari-focal lens are 4-9mm and 2.8-12mm.

The number of TV lines or TVL: In the analogue video transmission system, TV lines is a measure of picture resolution. The greater of the number of TV lines, the better the resolution and thus the higher quality of overall image. 420-540TVL is standard resolution camera, 600 is a good resolution, and over 650 tv line is high resolution. Recently market coming with HD-SDI camera, has resolution up to 1080P or full HD.

Buy camera depending on the camera sharp

Bullet camera: Most bullet cameras are weatherproof and sealed, with the flexibility to use different lens. The advantage of bullet camera is the small compact size and integrated design, most bullet cameras have built-in infrared LEDs. Infrared technology is simply infrared light for allowing security camera see at night, even at complete darkness. This kind of camera is the most used and sold camera, but please note the IR range works a certain distance (usually between 10 – 150 meters, depending on the model).

Box camera: The box camera with advantage of working with different types and size of lens. Easy to change the lens enable the box camera is useful to varies of surveillance application. But box cameras can not be used directly outdoor, they need an outdoor camera housing. 

Dome camera: Same features like the bullet camera, mainly designed to install on the ceiling, dome camera is more compact and discrete and vandal-proof. Camera board is hidden inside dome camera, it’s less invisible for the monitoring direction.

Security video recorder (DVR)

When setup a cctv system, customers not only need to think about security cameras, but also need to select one or two video recorder. Video recorder is the crucial component for cctv, with ability of video monitoring, recording and event management, as well as remotely surveillance.

There are two major types of digital recorders on the market right now:

PC-based video recorder: It’s a video recorder card and software installed on PC, with video inputs and record video on the hard disk. The advantage of these recorder is flexibility on upgrading, but main problem for this type of recorder is that you may use it for other purpose or usage, which will cause the system be vulnerable to software crash, system instability, also expose to virus…etc.

Standalone digital video recorder (SDVR): it looks like the old VHS recorder (or DVR player). With video inputs and audio inputs, based on Linux OS, video processing via hardware, therefore, avoid system crashes and video is also record on the hard disk in H.264 format. The SDVR has been designed and manufactured to comply with video recording for surveillance purpose, thus carries high performance and reliability.

Cable wiring

Although it’s possible to install wireless cameras, but from price differential with the wired camera. It’s obvious wired camera remain the most installed.

The most important thing is cable, regardless of the final method for the wiring, it’s preferable cable with good quality, this will prevent more than a headache in the future. There are two main methods used for the wiring; RG59 coaxial cable  and UTP video cable with RJ45. For the UTP video wiring, you need to use the devices called video balun, video balun need install on both fronts and ends.

We hope above information can clear some doubts for you. If you need more information, please contact us.