Veterinary Medicines Directorate, an executive agency of the Department for Environment, Food and Rural Affairs (Defra)
Found on http://www.encyclo.co.uk/local/20736
Video Motion Detector. A detection device generating an alarm condition in response to a change in the video signal, usually motion, but it can also be change in light. Very difficult to set up for use externally but can be useful in carefully controlled situations. Modern VMD systems can learn the scene and ignore such things as tree and foliage m... Found on http://www.zoo.co.uk/~z0001325/Glossary.html