Laser Thickness Measurement System Based On CCD Technology

With the development of modern industrial technology, the demand for thethickness of the various objects detection is gradually increasing. Based on lasertriangulation method, the use of the CCD image sensor, to achieve a continuousproduction line thickness of the coating line detection, through the preparation of PCsoftware to display and feedback results.The thickness measurement of objects isdivided into two methods of contact and non-contact. Laser thickness measurement isa typical non-contact method with excellent accuracy and real-time, at home andabroad have very extensive research for laser thickness measurement.While industrialproduction growing demand for high-quality coatings, the coating quality parametersmonitoring various detection methods and technologies are increasingly highrequirements. The optical thickness of the coating method has a wide measurementrange and high accuracy advantages.In this paper, the work is as follows:1. With the direct laser triangulation theory, the optical path of the thicknessmeasurement system has been designed. In a laboratory environment, theexperimental optical system is built to measure coating material sample.2. For gauging system, the extraction of crude processing after the wave data ofthe commonly used three kinds of sub-pixel faculae center localization algorithm(form method and difference method, the Gaussian fitting three times) for verification,after the precession of relevant convolution coarse. Verification results show thatGaussian fitting method can reach the best accuracy, the best spot center location.3. The laser thickness measurement system design. Overall thicknessmeasurement system includes CCD drive circuit, ADC acquisition circuit, USBinterface transmission circuits. Select STM32system as the main processor, the CCDdrive signal generated by the chip’s internal ADC module and USB module digital toanalog conversion and communication with the host computer.4、With the self-designed PC software, the data that collected by embedded modules is uploaded to the PC via USB. Thickness measurement of a grain has beendesigned. By measuring the thickness of coating material sample, the thicknessmeasurement system can be verified.Hardware and software design has been completed, the system is strictlydebugged. The results show that the laser thickness measurement system can achievethe purpose of accurate measurement of coating material sample thickness. In thelaboratory environment, the precision of this laser thickness measurement systembased on CCD reaches5microns.