WebGate WebEye A10 Guía de usuario descargar pdf (Pagina 38)

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WebEye SPD User’s Guide

(Appendix 2)

Frequently Asked Question

1. About WebEye’s Feature

1) What is WebEye?

WebEye is a Web camera server. WebEye is consisted of 3 components as CCD module, Web server,

and networking device. WebEye captures, processes, and transmits digital images through network. As

WebEye itself operates as a Web server, it does not require other dedicated server connection as PC

does. By installing WebEye itself at the desired site, you may monitor views from remote site.

2) What preparations are needed to install?

It needs no other equipment except power and network cable.

3) Which algorithm is used to compress digital images?

WebEye uses Wavelet algorithm to compress digital images. Wavelet is still-image based compression

algorithm. Still-image based refers to that WebEye does not capture motion pictures originally, but

rather captures still pictures. JPEG, the standard algorithm in image compression, is also based on

still-image. WebEye compresses and transmits very fast to present the still images as motion pictures.

Process of still image compressing and transmission requires high technology. MPEG is another

standard in image compression, but it is based on motion pictures originally.

4) What is the difference between Wavelet algorithm and JPEG in compressing digital images?

Wavelet is more efficient than JPEG by 30-300%. Higher efficiency of Wavelet comes from its

encoding method. Wavelet algorithm uses DWT(Discrete Wavelet Transform) while JPEG uses

DCT(Discrete Consie Transform). Due to its efficiency, Wavelet is going to be adopted as standard in

digital image compressing by JPEG2000.

Since Wavelet is not yet standardized, it requires to install Plug-in or Active-X control to see images

through standard Web browsers as Netscape and I-Explore. The size of Plug-in or Active-X control is

as big as 3 MB. And the size of 3MB needs quite a long time to download. Therefore, Wavelet is not

used commonly. However, WebGate Inc. has developed Plug-in or Active-X control of 300KB to

prevent inconvenient time consumption from waiting.

5) Can WebEye support multi users with different resolutions at the same time?

WebEye can support more than 100 users with different resolutions at the same time. Moreover,

WebEye has progressive mode and gray mode to support low speed network line users. A user can

monitor full resolution (360 X 243) color images while other user sees half resolution (180 X 121)

B/W images. And the third user can see the images reproduced in progress mode at the same time.

6) What is maximum transmission speed?

WebEye compresses and transmits 30 frames per second on 10 base-T Network. However this speed is

not equal to every user. Because transmission is depends on performance of user’s PC and network

bandwidth. And there are two viewpoints to calculate transmission speed.

The maximum transmission speed is 30 frames per second from user’s viewpoint. However, it does not

mean that everyone can receive 30 frames peer second. Because, transmission speed also depends on

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WebGate WebEye A10 Guía de usuario Pagina 38