Q What is the difference between PC-Base and Stand-Alone DVR?

A DVR is functioned as an “Image Compression Machine” which squeezes images and saves them into hard disk. In fact, image compression is complicated and need mass-data mathematics. It is the core-technology of DVR.

The major difference between Pc-Based and Stand-Alone Digital Video Recorder (DVR) is on Compression Format. PC-Based DVR utilizes high-speed calculating software to compact images. In contrast, Stand Alone DVR processes images by using specially designed IC chip to structure compressed formulation.

Q What is the difference between Operating System (OS) DVR and Non-operating System (Non-OS) DVR?

A Basically, OS can be divided into two major systems, Windows and Linux. All PC-Based DVR and parts of Stand Alone DVR rely on an Operating System to function. Frankly speaking, they provide End Users more functions and software to utilize than Non-OS DVRs.

On the other hand, Non-OS DVRs appear more stable than OS DVRs, since all software of Non-OS system are designed only for its self use.

Q What is Image Compression and how many Compression Formats are used in DVRs?

A The biggest advantage of a DVR is transferring analog image to digital and saving it to Hard Disk. Accordingly, compression method will be the key role of improving transmission as well as reducing memory size. Of the various formats, JPEG and MPEG is the most widely used in the market place. The major difference between JPEG and MPEG is in compression techniques. JPEG processes images by compressing one by one still picture but MJPEG compresses image sequence by sequence.

* JPEG compress method can be divided into JPEG, M-JPEG, and Wavelet; several formats.

* MPEG compress method can be divided into H.263, MPEG, MPEG-II, and MPEG-IV.

A Charge Coupled Device (CCD) is a kind of silicon device which contains an array of potential wells created through a series of column implants and electrodes. CCD is often used in Cameras and function like a memory device to record the variation of light.

In addition, the basic CCD chip unit (picture cell) is a pixel. The numbers of Pixels represent the amount of Optical Device which also means the resolution of Camera. Furthermore, the surface of the optical device, arranged in matrix order, possesses an ability which can keep an electric charge. When detecting optical signals, those optical devices will transform a light pattern (image) into an electric charge pattern (an electronic image).

Similar to CCD, Complementary Metal-Oxide Semiconductor (CMOS) is a optical memory device as well. It is constructed by Silicon and Germanium elements which result this semi-conductor possessing negative and positive electronic poles. This combination produces an outcome we call, “compensation effect”.

Both CCD and CMOS technologies have their own advantages and disadvantages. CMOS sensors are easier, less costly to manufacture, and are generally used for low-end applications. They need less power consumption than CCD sensors. On the other hand, CCD sensors are usually higher quality products with more accurate functionality.

Q What is Day & Night Camera and what is IR?

A The basic idea of a day & night camera is a camera that shows a full color image in daytime but monochrome at night. The camera can sense the amount of light exposure and switch between color and B/W modes automatically. To put it more simply, light sensitivity of most CCD cameras will reduce dramatically during the dark and the Camera will have the difficulties processing images. Day & Night Cameras are designed to increase its light sensitivity in the dark as well as reducing noise.

Day & Night Camera with IR technology

IR is the abbreviation of a “Day/Night Camera with IR technology”. Its sensor is designed to be able to accept infrared light. When the illumination falls, the camera automatically turns on its built in Infra Red LEDs, and changes to Monochrome for “In the Dark” viewing. It allows a viewing of areas in “Complete Darkness”