【作者】 陆子凤；

【导师】 刘益春； 卢振武； 孙强；

【作者基本信息】 中国科学院研究生院（长春光学精密机械与物理研究所） ， 凝聚态物理， 2010， 博士

【摘要】 非接触红外测温技术由于不影响和改变温度场分布、能远距离测量、测温范围宽等优点被广泛应用。但因物体的发射率一般小于1,会反射周围物体辐射、太阳辐射等进入光学系统,导致热像仪的显示温度不同于物体的真实温度,结果往往造成错误判断,给使用者带来麻烦和经济损失。因此考虑各种影响因素,消除测温误差,在应用方面有着重要的价值。本文通过对热像仪进行光谱辐射定标,实现了温度测量。对影响测温精度的因素进行了分析和探讨,提出了对测温结果进行修正的办法。利用标准面黑体源在实验室条件下对红外热像仪进行校准,建立了图像灰度均值与黑体温度之间的数学模型。分析了目标到红外系统的测试距离对测温精度的影响。利用红外热像仪探测面上照度与像方孔径角的关系,对测试距离的影响进行了理论分析；比较了不同距离处测量温度与真实温度的差别。理论分析了发射率测量误差、环境温度测量误差对测温精度的影响。得到如下结论：物体温度越高,发射率设定不准引起的测温误差越大；物体的温度升高,环境背景的温度测量不准引起的测温误差将变小。因此在测温时,如果物体的温度远高于环境温度时,则发射率的影响不容忽视,当物体温度低于或者和环境温度接近时,环境温度的影响将变大,需要对测温结果进行修正。进一步研究了红外热像仪内部温度对测温精度的影响,结果表明：探测器的工作温度不同,探测器响应状态也不同,导致测温结果不同。测温时保持探测器内部温度和校准时相同,能有效避免因两者差异导致的系统误差。为实现三波段成像,利用一个能响应三波段的探测器共用一个光学系统,实现了照相机在紫外、可见、近红外波段的成像。测定了三个不同波段滤光片的透射率,利用积分球均匀光源实现了三波段照相机的光谱辐射定标,对应不同曝光时间(0.125-8 ms有7档可调),建立了探测器输出图像灰度均值和输入辐亮度的关系,为相机适应不同波段清晰成像提供了适当曝光参数选择。更多还原

【Abstract】 Non-contact infrared temperature measurement has been widely used in industry and national defense due to its many merits such as not changing the measured temperature field, the wide temperature measurement range, and the ability to measure both distant and small objects and so on. Since the emissivity of the object is normally less than 1, those radiations reflected from background objects and radiated directly from solar can enter into the optical system inevitably, which will then cause the error on the temperature measurement and thus might bring huge economic losses to the end users. In this paper, factors that affect the precision of the temperature measurement are systematically analyzed and solutions to eliminate the errors are put forword.The thermal infrared imager was calibrated by using a standard black body light source with a plate shape in laboratory, and the relation between the average grey level of the black body’s image and its temperature was derived. The influence of the object-system distance on the accuracy of temperature measurement by using IR System was analyzed. With the relation between the illuminance on the focal plane array of the IR system and the numerical aperture of the image space, the theoretical analysis of the influence of object-system distance on the accuracy of temperature measurement was carried out. The temperature difference between the measured temperature and the real temperature versus the object-system distance was characterized. A solution was proposed to reduce the measurement error and increase the temperature measurement accuracy. The influences of emissivity measurement error and background temperature error on temperature measuremet are analyzed. The results show that the higher the object’s temperature, the larger the temperature measurement error. In particular, when the object’s temperature is close to the background’s temperature, the influence of background’s temperature on temperature measurement is obviously signicant and can not be ignored. Therefore, if the object’stemperature is higher, the emissvity’s effect on the temperature measurement must be considered. On the other hand, if the object’s temperature is lower, the background temperature’s effect on the temperature measurement must be evaluated and corrected.In order to reduce the error further, the influence of the imager itself and the temperature rise of focal plane array(FPA)on the accuracy of temperature measurement was discussed and characterized as well. The experimental results show that the measured temperature is dependent on the FPA’temperature. when the FPA’ temperature is stable, the measured temperature is smaller than the real one, the relative error is within the range of 8-10%. Therefore, a proper compensation of this parts error can effectively reduce the temperature measurement error.With a three-waveband CCD sharing one optical system, a camera which can image in ultraviolet, visible and near infrared wavebands is realized. The filter transmissivity in three wavebands of ultraviolet (350-380nm), visible (380-760 nm) and near infrared (760-1000nm) has been obtained. Using integrating sphere as a uniform light source, calibration of the three-waveband camera was done. The relation between the grey level of the image and the radiance of the integrating sphere for different exposure time ranging from 0.125 ms to 8ms in three wavebands is characterized. It is shown that the grey level has a linear function with the radiance for different exposure time in all three wave bands.更多还原