测量系统特性对压敏涂料校准影响的实验研究

针对压敏涂料(PSP)的特性,基于自行建立的光学压力测量系统,研究了CCD相机光圈与激发光源强度对校准结果的影响。对压力为27.4～147.4kPa,相机光圈F值为2.8～11.0,激发光源在200W、400W两种强度条件下分别开展了国产压敏涂料的校准实验,每一采样点采集20次。通过对所采集荧光图像进行平均、比运算等一系列图像处理后,可得到不同条件下的压力校准曲线,分析了相机光圈与激发光源强度对压敏涂料压敏特性的影响。实验研究结果表明:经过比运算可以消除系统和光照不均匀对压敏涂料发光的影响;激发光需具有一定强度,激发光的强度要足以使涂料中的光敏分子产生能级的跃迁;相机的光圈值越大,所采集到的图像信噪比越大,获得的压敏涂料校准曲线斜率越大。

Experimental of Study Influence of Measurement System Characteristics on Pressure-sensitive Paint Calibration

This article studies the impact of different CCD camera apertures and different powers of excitation on the calibration of a pressure-sensitive paint (PSP) by means of an optical measurement system designed and built by the researchers. Calibration experiments are performed for a PSP made in China at pressures of 27.4-147.4 kPa, apertures F between 2.8-11.0, and power of exciting light 200 W and 400 W, collecting samples 20 times at each sampling point. Calibration curves at different pressures are obtained after a series of fluorescent image processing, and analysis is made on the effect of camera aperture and excitation power on the characteristics of the PSP. The experimental results show that the influence of uneven illumination can be removed though division, and that the exciting light must be strong enough to provide the energy for the photosensitive molecules to realize energy level transition. The larger the aperture is, the greater the image signal to noise ratio is, which results in a greater slope of the calibration curve of the PSP.