A VIDEO MONITORING SYSTEM FOR SPring-8 ACCELERATORTUNNEL
M.Kodera, T.Fukui, SPring-8, Hyogo 679-5198, JapanAbstract
We developed the video monitoring system using web
camera for SPring-8 accelerator tunnel. It replaced oldsystem to consist of video cameras and video switchers.
The old one was not convenient because a video display
and location of cameras were fixed. The web camera isable to move any location if it could connect to a network.
Also we can see pictures on any PC and workstation
using the web browser.

1 INTRODUCTION
At the beginning of the SPring-8, the camera ofradiation safety surveillance, which could only be used in
the accelerator tunnel, was not suitable for seeing theaccelerator components. The eight sets of camera were
installed to monitor the entrance. Another problem was
the failure caused by radiation. It occurred frequency.
We built the system for the surveillance of theaccelerator components by using of the Web technology.
This monitoring system consists of a CCD camera, thenetwork camera server, which captures the NTSC video
signal into a jpeg picture, the http server, which receives arequest from a web browser, and the network equipments,
which connects these.
There are two kinds of http servers. One of them calls"real-time server"; another server calls “public server”. A
common function to these http servers is offering the html
files which arrange the picture of the selected camera in
one screen, or display it by time-lapse. Thereby, it is notnecessary to input an individual network camera server's
URL from a Web client.
This system is limiting the authority to decide the angleof a camera, and optimizing load by the functional
assignment of two sets of these servers. As for thedifference between two servers, real-time server hasaccess restrictions, and public server need to restrict thefunction. The real-time server's access permission wasgiven to the Web client of a central control room (CCR)
by using a firewall. The public server does not raise theload of the camera servers and network traffic.

2 SYSTEM EQUIPMENTS
2.1 CCD camera
The CCD cameras were installed in the tunnel, and it
can operate pan-tilt and zoom by remote with a serial line
(RS-232C).
We adopted "Canon Communication Camera VCC4"[1] as the camera. Since the camera is small, it is easy
to put the cover it by lead sheet, which prevents fromradiation damage.

In this system, 24 cameras are installed in anaccelerator tunnel.

2.2 Network camera server
The network camera server capture an NTSC picture
into JPEG file, and transfer the file by the http or the ftp
protocol.
We adopted "CHUO ELECTRONICS ND-VW04"[2]as the network camera server.
This has the function to control pan-tilt and zoom ofcameras from a web browser via serial communication.
This has four NTSC input and two serial line. Weconnected two cameras to the serve. Other NTSC input
will be used temporarily. In this system, the 12 camera
servers are installed to the maintenance corridor of thestorage ring.

Figure 1: The CCD camera “Canon VC-C4” with leadcovers. And the network camera server “CEC NDVW04”

2.3 HTTP server on Linux PC
2.3.1 Two http servers
The real-time server is accessed from operation
consoles at CCR, and it sends a direct picture from thecamera servers and controls the pan-tilt and zoom of acamera. There is a limit of number of connection toaccess to this server from CCR.
The function to save pictures to raid disk was also
attached to this server.
On the other hand public server could access frommany and unspecified clients of SPring-8 site and it sendcached image on a local disk.
This cache is updated every 5 seconds (this can changea setup) for all network camera servers. Even if there aremany sessions to this server, any network camera server's
load is not affected.

Table 1: Linux http servers’ common specifications
Case2U Rack-mountedCPUPentium III 1GHz x2

Main-memory

512MB

HDD

18GBTape drive

DDS-4

SCSI

Ultra-160

NIC

1000Base-Tx1+100BaseT x1

RAID*

18GB x6 (RAID5 Hot swap x1)

OS

Linux/RedHat6.2

httpdApache

JAVA servlet

Tomcatcamera server's image data is displayed directly on a web
browser. This function is implemented using URL addressthat the camera servers into the image source (<imag src>tag) of the html file. The real-time server can also show aserver push animation by this method.
In the case of a public server, the html file wasgenerated with image source, which specified the cachedfile on this server.
In addition, it sets the parameters, such as a changeinterval of a display picture.
There is a function that records the picture of thecamera on the RAID disk in the real-time server. Theparameters for this function the camera channel, which
records a picture, its interval etc, are set from a web client.

*RAID: Connects with the server only for operation
consoles

2.3.2 Software processing of a server
The http server generates the http files with thedemands of a web client, and sets parameters to control
the camera and the camera server.
The flow of the process for operation is shown inFigure 2, and the class architecture of servlet applicationis shown in Figure 3.
When a web client uses the real-time server, a network

Figure 3: The class architecture of servlet applications

3 CONSIDERATION OF RADIATION
The lead cover is attached to the camera (2.1 Figure 1).
We used a 0.5mm thickness of lead sheet in order toFigure 2: The flow of the processing (for example, the server only for operation console)

Figure 2: The flow of processminimize a weight of the movable part, and 1mm
thickness for other part.
The data of EEPROM was volatilizing under the strong
radiation. EEPROM is near the lens and another one is
inside a base stand.
The position where a camera breaks down or not wasdivided clearly. Then, we measured the strength of theradiation along the accelerator tunnel. The measurement
used the glass dosimeter to attach the wall in the storage
ring at intervals of 1.5m, and was operated an accelerator
for 68 hours.
We got a result that the radiations near bending magnets
were extraordinarily strong than other positions. The

crotch and absorber, which synchrotron orbital radiation
hits, are the sources of radiation.
We select a position of the camera to minimize theradiation damage (Figure 5). We moved the camera
position at higher radiation to lower radiation.
Consequently, there was no failure of the camera byradiation.

6 ACKNOWLEDGMENT
We are grateful to Mr. Shinya Ohishi, Dr. Tamotsu
Magome at SPring-8 accelerator vacuum team, Mr.
Tetsuya Takagi at SPring-8 safety office.
In accelerator vacuum team and safety office, we
received great support of a radiation measurement.
Moreover, in safety office, we received much advice andguidance from the plan stage of this system.

7 REFERENCE[1] http://cweb.canon.jp/Product/vsl-com/gazo/vc-c4.html[2]http://www.cec.co.jp/CEC/products/net/netdev/ndvw04/

Figure 4: The network of the system

Figure 5: The radiation mesurement