An Optical Mouse To Detect Counterfeit Coins

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TECNOLOGÍA | Estudio de la Universidad de Lleida TECHNOLOGY | Study at the University of Lleida
The sensor incorporates optical mice for computers are often used to guide the movement of the cursor, but can be used as a detector of counterfeit coins. This is demonstrated by a prototype developed by engineers at the University of Lleida (UDL), details of which are available freely and free in the journal Sensors.
"We have implemented a detection system of two euro coins by comparing patterns obtained with an optical mouse sensor," explains Marcel Tresanchez, one of the authors.. The European Commission, 79% of counterfeit coins discovered in Europe in 2008 were of two euros.
To detect counterfeit currency is put into a positioning device and is rotated. The sensor, located a few millimeters, is used to capture images of the common face with the two-euro coins (all have a map of Europe on one side, and a specific design of each country on the other). Finally the images are compared to reference other valid currency obtained through an algorithm that also developed the Catalan team.
"The same operation could be done with a webcam, for instance, but the advantage of these sensors is their small size, low cost and the viewing angle so small that it can capture the attention of the coins is a simple way," says Tresanchez.
The researcher explains that not just any optical mouse sensor since it must capture the images in real time, with a minimum resolution of 15x15 pixels (the team has used one of 30x30 pixels). It is also advisable that it is an LED-based sensor or infrared and laser technology not because these images available too broad.
The study results show that this system, designed to complement the identification of forgery techniques, to detect counterfeit money better than you would an ordinary person, albeit at a level similar to that of an expert trained to do so The authors have also applied the same method to design an "encoder or rotary encoder (counts angular displacement of an axis) using an optical mouse sensor.