Design And Implementation Of Photoelectric Detection System Based On Digital Filtering

Since 21st Century,photoelectric detection technology has been applied to various aspects such as household,industry and military.Meanwhile,the rapid development of computer technology has provided strong support for the later processing of photoelectric detection data.In the data processing,traditional analog filter needs the stability and reliability of the circuit,while the stability of the circuit is susceptible to the environment and some other factors.Developing a photoelectric detection method based on digital filtering is significant.In this paper,a set of photoelectric detection system of double light road single detector is designed in the aspect of digital filtering to meet the needs of special detection and improve the stability of the system.The system is mainly composed of three parts:first,a single detector detection device based on dual channel,which mainly produces signals of two different frequencies and converts the light signals into electrical ones.Second,the converted electrical signals were sampled utilizing a 12 bit sampling precision STM32F407VET6 single-chip microcomputer and the data were outputted through the serial port.Finally,The Visual C++6.0 integrated development environment is used to develop a digital filtering software.The development of the software includes building an external framework using the Microsoft basic class library(MFC),calculating the spectrum of signals by Fast Fourier Transform Function(FFT),realizing the filtering processing of the signals by designing the window FIR filter function and displaying the processed data on the software through the memory drawing.In order to verify the reliability of the system,the filtered data of FIR digital filtering software were first saved locally.Simultaneously,we conduct sine wave fitting and effective value calculation of the raw data read by oscilloscope.The frequency spectrum of the two frequency superposed signals were calculated by using MATLAB.Compared the two frequency signals of the digital filtering software with oscilloscope,the ratio of the effective values was approximate.Therefore,the system can be used as a dual channel and single detector photoelectric detection system based on digital filtering.