The Design Of Digital Refractometer Based On Automatic Collimation By Double CCD

As everyone knows, the refractive index and the average dispersion are ones of theimportant optical constants of materials and by these two parameters, we can get opticalproperties, purity, and dispersion size of different materials. Abbe refractometer is a precisionoptical instrument specifically to measure refractive index value, concentration and averagedispersion of different solution. This instrument was widely used and is one of indispensableequipment at the oil industry, oil industry, pharmaceutical industry, paint industry, dailychemical industry, the sugar industry and geological survey and other relevant factories,schools and the relevant scientific research unitsThe traditional Abbe refractometer is operated completely by manual mode and itrequires the user to record material refractive index value by visual way and manualoperation.Because of depending on manual operation to achieve the measurement results, theartificial measurement error will be hard to control. And because the operation procedure istoo tedious, the measurement efficiency is very low. In order to improve this situation, themarket also appeared a variety of imported products digital refractometer. However, sincemost of optical part structure designes are more complex and the requirements of processdesign are very high, the digital refractometers are generally more expensive.In order to find a balance between refractometer product performance and price, thispaper described in detail the scheme construction and specific hardware and software ofdigital refractometer, which used double linear array CCD (Charge-coupled Device) to realizeand had the automatic aiming function. The scheme still uses optical structure of traditionalAbbe refractometer. By using two pieces of high precision linear array CCD image sensor device in circuit component, they collected data respectively for positioning light andrefractive light image. And then software calculated the offset value of different materialsaccording to the field image characteristics and calibration curve by processing the data fromCCD. This paper also presents a new tangent edge location algorithm based on curve fittingand the simulation has confirmed the rationality of the algorithm according to the actualsample data.In addition, this article also designes a set of automatic calibration software for digitalrefractometer to aims at artificial calibration problem.The software development is based onWinCE embedded system and Labview virtual instrument.This paper decribes detaily thesystem automatic calibration software design process and the realization method and theirfeasibilities are validated in the actual calibration operation.The software can automaticallygenerate the calibration fitting curve andautomatically deposite it into the device for storage.Users will save more time at the actual calibration process through the use of the software.After more than a year of development, debugging and testing, the project has beenbasically completed and it has realized the setted performance index and functionalrequirements. The project will improve the testing efficiency and accuracy greaty of digitalrefractometer.