Small Three-dimensional Laser Fluorescence System

Different algae contain different pigments, resulting in differences in theirfluorescence spectrum. The Fluorescence spectra can be obtained by fluorescencedetection devices and then used for classification on the algae. Conventionalfluorescence detection typically use PMT array as the spectral detector, althoughhaving a high spectral resolution, but very bulky too. In addition, because theexposure time can not be adjusted, the detection of the fluorescence in the lowerconcentration of seaweed is not ideal. This paper presents the design of the miniaturespectrometer based on linear CCD with continuously adjustable exposure time.The uses of SNOY’s2048-pixel CCD linear sensor as the spectral detector andoptical system based on Czerny-Turner structure reduce the instrument’s volumeeffectively. According to this design, one of Altera’s Cyclone III seriesFPGA-EP3C25F324is used as the system control core. The timing-driven module ofCCD and ADC, accumulator module and accumulator control module areimplemented in the logic units of FPGA. Based on the SOPC, NIOS II softcoreprocessor, serial communication module and SD card file storage module areintegrated. The software about system parameters set, spectra collection and analysisis developed based on LabVIEW.At last, the imitation experiment about the design shows that the miniaturizedspectrometer can achieve continuously adjusting exposure time andmulti-wavelengths measurement simultaneously.