Cmos Single-point Laser Triangulation-based Ranging System

Nowadays, for the particularity of laser range finding, the technology of laser range finding that currently in use can't meet the demands of range finding in some special fields. There are high demands for equipment and apparatus to the high precision, today's laser range findings have some disadvantages.In practical application, the needs of middle and short distance measurement are widespread, but so far, no cheap, simple, high precision measurement is brought forward. After several kinds of laser range finders that currently in use are introduced, whose technological advantages and disadvantages are analyzed, a distance measuring using single-point laser triangulation is proposed.A new advanced triangulation is proposed to get a proper accuracy for either near or far distance by adopting different parameters. Adopting CMOS is the main innovation to make the price and power low. This dissertation can be divided into several parts. In the first part, the triangulation is proposed, and the parameters of optical system structure are also determined, which are used in short distance and long distance respectively, at the end of this part, the errors of the whole system are worked out via theoretical analysis. In the second part, the hardware of the system is introduced. The particular functions of some key parts are analyzed such as lens, CMOS, MCU, FLASH and LCD. In the third part, the design of software is introduced and the realization of each part of the system is also discussed, the characteristics of kinds of surface are analyzed, a method of fitting centroid location after taking a threshold in areas is brought forward, which solved some difficulties in finding centroid of special surfaces. In the fourth part, the experiment equipment is established, images are captured through CMOS, and the result of experiment is analyzed and the calibration curve is drawn, due to the non-linear characteristic of the used light-sensitive transducer's calibration, the method of using piecewise linear line to approximate CMOS calibration curve is proposed, which decreased the measurement errors greatly, analyzed the measurement errors and proposed the methods of minishing errors. At the end of this dissertation, it summarizes the content of the whole system, and also discussed the futureimprovement.