中文摘要：

目标发射率测量是目标红外辐射特性测量的基础。介绍了一种基于环境辐射改变的目标发射率的测量方法。分析及推导了到达探测器上的辐射量，通过改变环境辐射的方法测定目标的反射率，进而得到物体的发射率。在实验室内采用黑体作为主动辐射源改变环境辐射，对三种物质分别进行发射率测量，与直接测量的发射率进行比较，结果最大误差为0．017，达到了实际需要，验证了该测量方法的可行性和准确性。该方法为红外辐射非接触精确测量物体温度提供了必要参量。

英文摘要：

Target emissivity measurement is the foundation of target infrared radiation characteristic measurement. The radiation of target and surroundings is analyzed. The amount of radiation reaching the detector is derived theoretically. A method of emissivity measurement based on the change of the enviromnental radiation is proposed. Object emissivity is obtained indirectly by measuring the reflectivity through changing the environmental radiation. The enviromnental radiation is changed by an extend blackbody chosen as initiative radiation source. Experimental study has been per- formed with various materials. The results are compared with the direct emissivity measurement. The maximum errer is 0. 017. The feasibility and accuracy of the proposal approach are verified. This study provides a referenee for aceurate non-contacting infrared thermometer.