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GeoVision Digital Video Surveillance System

Digital Watermark

What is digital watermark?

Digital watermarks are added to still images in a way that can be seen by computer but is imperceptible to the human eye. A digital watermark carries a message containing information about the creator or distributor of the image, or even about the image itself. A watermark is used to communicate copyright information about an image in order to reduce copyright infringement.

Why image should be watermarked?
The benefit of using digital watermark is to protect valuable images by communicating the copyright or track down uses of image on the web. For surveillance system, it can be used to prevent counterfeit or destroying recorded images by the proof of authority so it can be legal evidence in court.

How does the watermarking system work?

geo vision digital watermark

There are two pictures above; one is with watermark and the other is without.

We all know that a picture is made up by lots of pixels. What we do is breaking all the pixels of GeoVision logo and put it into a picture/image without notification and imperceptible to human eye. To detect, you need to use a file (WMProof-New.exe) contains in GeoVision software

Factors that will influence watermark survival
If you see the restored picture above, you will find the picture is not as perfect as previous one. There are many factors will influence watermark survival.

1. Image Variations/Randomness-
Because the way that digital watermarks are embedded, an image being watermarked must not be composed mostly or entirely of a single flat color if the watermark is to be imperceptible. In flat area, the watermark intensity is decreased, while in detailed regions the intensity is increased.

2. Compression methods-
If using lossy compression methods such as JPEG actually remove some image data in order to decrease file size


Henrys Electronics Ltd
404 Edgware Road, Paddington, London, W2 1ED, UK,
VAT Number : GB 241 7629 61
Tel:+44 (0)20 7258 1831, Fax:+44 (0)20 7724 0322, email:


All prices exclude 17.50% VAT, and Carriage Charges. For UK and Europe Please Add 17.50% VAT To All Prices, E & O.E. Last Up dated and Validate January 2004. All comments or enquires to: layout and design Duncan Evans, Copyright ©1997-2004 Henrys Electronics Ltd.