Design of a fingerprint, biometric identification system using capacitive sensors

A fingerprint, biometric recognition system was designed. The system is based on the digital processing of fingerprints of 256 x 300 pixels, which are recorded by a capacitive sensor and then transmitted to a PC by means of a communication interface. Successive steps of configuring the sensor, obtaining the image, and communicating with the PC were conducted. Image processing is performed by the PC using own digital image filtrate algorithms. The first level of filtering stresses the valleys and crests of the fingerprint; the image is divided in regions for applying this algorithm. The next algorithm filters the image to extract the most relevant characteristics. Subsequently, the image is converted to only two levels of gray, and the crests are converted to one-pixel width (skeleton). Finally, recognition is done by seeking the location of the relevant characteristics of each fingerprint and determining the distances between them, generating information vectors.