A laser triangulation range finder based on a chaotic modulation and detection scheme is presented. An elementary non-linear electronic oscillator composed by two operational amplifiers with feedlback current form two antiparallel diodes generates a chaotic signal that is used to generate a chaotic clock modulation with a well-defined broad band spectrum. This chaotic clock modulates a laser beam that is transmitted and received by a collecting optics in a laser triangulaton range finder scheme. A band limited phase delay equalized amplifier sends the received signal to a balanced demodulator using the same chaotic generated signal as "local oscillator". A low pass filter is tuned to assure good compromise against noise immunity and the desired response speed. This modulation scheme allows several lasers stations to operate in same working area, avoidng carefully adjusted field-of-view screening and cross-detection false alarm due to the interference of other laser stations. The Chaotic modulator cna be used as an alternative form icroprocessor based pseudo random sequence gneerator when board space or cost is a critical system specification. The laser triangulation range finder has a range of 0.5m to 2m, using a 3mW class IIIa visible laser ,with precision of 5 mm.
展开▼
