ABSTRACT
In present time electronically controlled sensors are experiencing an astonishing progress. Beside their availability in almost all applications – according to several physical properties, their prices are rapidly decreasing.Among all recently available sensors, digital cameras based on CCD or CMOS technologies are currently very precise (if adequate optics are used). They offer high resolution together with a very attractive economical cost. Even if inexpensive optics are used, it is easy to introduce procedures for the calibration of the system so that an optimal precision is reached (Torres & Menéndez 2004).
