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First,
it is neccessary to distinguish between a network camera and a
webcam. The common ground is that both solutions can record an
image and transfer it to a server in almost real time. If you
are looking to put an image on a non-commercial website, where
reliability is not too important, then you can probably get away
with a low cost webcam which would plug into your PC.
Solution
: plug-in webcam for normal PC
Description
: A low cost device (typically £30 - £100 from
high street stores). The connection to the pc is usually by parallel
port or USB. You would upload images to your website using software
such as the excellent webcam32
from Neil Kolban . You would then update the images automatically
by using a java applet.
Advantages
: Cheap! This is a good way to get images of your goldfish
onto your website. They are easy-ish to set up and get running
and is a good first step into the world of webcams.
Disadvantages
: They require your pc to be on 24/7 and running the transfer
and capture software. You have to remember to start the software
again after you reboot. The cameras are low-specification which
means they can't handle very low or very high light levels. They
are also likely to get damaged if you point them at strong daylight.
Also, you can't install the cameras outdoors. (Actually, there
is a variation on this theme, which would allow you to use a better
quality camera with your home pc - see case
study #1). If you want a webcam presence on a commercial site,
this is not the way to go, as you need to rely on someone to make
sure that the software is always running on the pc with the cam
and working. This wastes either your or your employees time.
Solution
: Dedicated Network Camera
Description
: These devices are a one-unit solution, containing a small
dedicated processor within the camera assembly. This means that
you don't need a PC to attach the camera to. The devices can plug
directly into a network socket (case
study #2) or a normal phone line or isdn line (case
study #3).
Advantages
: Require no attention once installed (other than a recommended
6-monthly preventative maintenance). Require no seperate pc. Far
more professional appearance to the units. The units can be used
at varying light levels and some can be used in bright daylight.
Compatible with external cctv enclosures for outside use. Cameras
for internal use can be supplied
preconfigured with all neccessary settings so you can just plug
them in and an image appears on your site! As a dedicated solution,
it is far more fit-for-purpose and lower cost than buying a seperate
webcam and pc. Web interface allows settings to be changed via the
internet using a browser.
Disadvantages:
Network cameras require specialist installation, especially external
cameras (enclosures need to be heated and weather sealed).
Solution
: Patch into existing CCTV
Description
: If you have an existing cctv system, it is possible to use
your existing video feed to send images to your website.
Advantages
: Very simple physical installation, can be supplied preconfigured
for internet connection. Low cost - no need to buy extra dedicated
cameras. Monitor your workplace/warehouse remotely (via a password
protected webpage).
Disadvantages
: May be invasion of privacy/security issues regarding display
of "security camera" images on your website (this is
not a disadvantage if the website pictures are password protected
and not meant for public view.
There's plenty of applets out there.... A couple of good ones
are tv.class and javacam.class.
These are in .zip format so that you can download them without your browser trying to run them! An applet is a Java application which is downloaded when someone
visits your site. It is a program which is run by the browser.
Most browsers have Java support so there's very few compatibility
problems..
To put the applet on your page, you need to upload it to your
site and put it in the same directory as your camera images and
your webpage which has your cam stuff on it.
You also need to include the following HTML in your webpage
<applet code="tv.class" width="320" height="240">
<param name="interval" value="60">
<param name="image" value="image.jpg">
</applet>
Or With JavaCam.class
<applet code="JavaCam.class" width="320" height="240">
<param name="interval" value="60">
<param name="url" value="http://www.yoursite/webcamdirectory/image.jpg">
</applet>
There are other ways of displaying cam images, such as server
push, but such systems don't always work with all browsers.
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