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MEDWAY RAYNET GROUP Affiliated to the Radio Society of Great Britain |
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These Images are being used to compare different image definitions on the web.
The principle is to initially transfer webcam quality JPEG images of 640 by 480 source definition to an internet or intranet page, this has a small file size of 56kByte, and so can be transferred via a 9600 baud radio modem.
If required this can be followed by a higher definition image source of the same scene, or part of the scene. The high definition page would allow greater detail, for example, look at the houses in the distance on the low definition image, then look at them on the enlarged image, you are getting the zoom just using internet explorer. But more importantly if there is a need you can right click on the image and save it to hard disk, and then display it on an image program like MGI Photosuite, Paintshop Pro etc, this will allow the image to be zoomed into to show closeup detail on a projector.
Garden shot one is in 640 x 480 resolution This gives a full Internet Explorer page width, it displays well on the web BUT will not stand zooming into as it will soon pixilate.
Garden image 640 by 480 pixel source.
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The source of the image below has a 1600 X 1200 pixel resolution, this naturally takes a time to display on a slow 56k modem connection but is very fast on ASDL at 500Kbit or 2Mbit. This image overfills the page on purpose to allow you to see greater detail using a standard browser, this picture taken from the same position as the picture above but using the zoom on the still camera. Look at the houses in the distance for the improvement, it can be resized to fit the page width if required see lower down.
The larger size as displayed above can be resized (see below). This image source is a much higher quality and can be saved by right mouse click, and then zoomed into to give a closeup display in MGI photosuite, or petshop pro etc. and for display on a projector screen.
Garden image 1600 by 1200 source.
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Spring....The image source below is 580 x 435 pixels and is displayed as a comparison.
For Exercises an Image template has been set up on a number of pages with a set filename sequence, this enables publishing to be just a matter of downloading the file to the internet with the preset filename. Images sent via packet only need to travel to the nearest amateur station with internet access preferably with ADSL for the larger images.
These pages are in open display but can be password protected and encrypted to a high standard as used in electronic banking.
The VC-H1 is being supported by all groups and works well with the method of transmission proposed above. By also using Digital Still Camera's we can achieve a higher quality image and also have a backup to SSTV which is a very important consideration.
The WA4DSY 56kb Radio modem could be used to speed up the transfer of the higher definition images. The output IF of this modem is on the 10 metre band at 2mW this can be fed into a transverter to the appropriate amateur band.
The use of Class 1vBluetooth integrated digital still camera's allows a local transmission of up to 100 metres This will then be sent across greater distances from the local control vehicle using higher power 802.11b specification signals working at 11Mb/s at 2.4GHz.
Digital moving images can be displayed in the same way using the higher speed modems.
Michael Rose G3VPA.
Photographs Copyright © Michael Rose 2002. All Rights Reserved.
Copyright Medway
Raynet Group.
Last revised: September 18, 2003