The Design Of Double Wavelength Optical Fiber Radiation Pyrometer And Research Of Its Applied Techniques

Since transferring and sensor technology of optical fiber has some advantages in practices, radiation temperature measuring based on optical fiber is rapidly developed. In recent years, brightness optical fiber pyrometer is widely applied. However, in some circumstances there are measurement errors caused by variation of transmitting rate, dust, vapor, and losing accuracy of detector. A system is constructed in this paper to diminish the errors above in order to enhance temperature-measuring accuracy. Optical fiber radiation pyrometer is intensively investigated. Based on the principle of blackbody radiation and by using double-wavelength approach, wavelet filter is adopted for denoising to obtain higher temperature-measuring accuracy. To take into account temperature measuring range, sensitivity, relative sensitivity, linearity and spectrum response of detector, the selection of wavelength of two waves is thoroughly studied and selecting area of parameters is determined by numerical calculation. The performance and construction of each component of the pyrometer are depicted in details. Filter rotary device is designed for colorimetric system of double photoelectric detector and temperature-measuring experiment is conducted. Based on the different characteristics in static signal measurement and dynamic signal measurement, time frequency multi-resolution and local feature properties of wavelet transform are applied to carry out wavelet decomposition of the output signal of color metric optical fiber pyrometer in multi-scale. Therefore, filtering algorithm of soft threshold is used to denoise and signal-to-noise ration is improved. Experiment indicates that it is feasible to apply wavelet transform to the signal processing in radiation temperature measuring and filtering is satisfactory. This replaces conventional filter amplifier and it is easy to realize signal processing of radiation temperature measuring using software. The work in this paper makes attempt to apply wavelet transform to the area of radiation temperature measuring and it would be referential to the practice in industry.