热像仪聚焦程度对红外辐射检测的影响研究
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摘要
热像仪主要依据红外辐射定律对物体由于温度产生的红外辐射进行测量,是非接触式测温方式的一种方法。在保持其它影响测温精度因素不变的条件下,通过保持热像仪稳定输出来提高精准度。实验采用黑体作为目标辐射源,并将温度设定后保持不变。保持热像仪与辐射源的位置固定不变,只调节聚焦程度来采集数据。分析热像仪聚焦程度对其输出值的影响,通过分析可以看出对于均匀的辐射目标源,当热像仪离焦时各个随机点输出的值不一致。只有当其在聚焦的状态下,随机点及区域输出的值才趋于稳定。并计算各点的在不同聚焦程度下的变异系数及区域内方差,进一步确定热像仪输出值的稳定性。实验表明:热像仪聚焦程度对其输出值有较大影响,利用文中聚焦程度与变异系数、区域内方差的计算对于判别热像仪输出值的稳定性具有一定的作用。
Based on radiation laws, infrared radiation caused by temperature can be measured by thermal imagers, as one of non-contact temperature measuring method. Keeping other factors unchanged, we manage to improve the precision of thermal imagers. We used blackbody as the target radiation source, and the temperature is set to remain unchanged. Keeping a fixed distance between the thermal imager and the radiation source, we adjust the degree of focus to collect data. Influence of the degree of focus of the thermal imager on its output values is analyzed. It can be found that the values of the random points are not consistent with uniform radiation target sources, when the thermal imager is out of focus. Only when it is in a focused state, the random points and the regional output values tend to be stable. Variation coefficients and variances of every points in the region in different focusing degrees were calculated, the stability of the output values of the thermal imager were determined. The experimental results show that the degree of focus of the thermal imager has a great influence on its output values. Variation coefficients and variances in the region can be used to determine the stability of the output values of thermal imagers.
Based on radiation laws, infrared radiation caused by temperature can be measured by thermal imagers, as one of non-contact temperature measuring method. Keeping other factors unchanged, we manage to improve the precision of thermal imagers. We used blackbody as the target radiation source, and the temperature is set to remain unchanged. Keeping a fixed distance between the thermal imager and the radiation source, we adjust the degree of focus to collect data. Influence of the degree of focus of the thermal imager on its output values is analyzed. It can be found that the values of the random points are not consistent with uniform radiation target sources, when the thermal imager is out of focus. Only when it is in a focused state, the random points and the regional output values tend to be stable. Variation coefficients and variances of every points in the region in different focusing degrees were calculated, the stability of the output values of the thermal imager were determined. The experimental results show that the degree of focus of the thermal imager has a great influence on its output values. Variation coefficients and variances in the region can be used to determine the stability of the output values of thermal imagers.
引文
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[6]张勇,王新赛,贺明.距离对红外热像仪测温精度的影响及误差修正[J].红外, 2011(2):24-27.ZHANG Yong, WANG Xinsai, HE Ming. Influence of distance on temperature measurement accuracy of infrared thermal imager and error correction[J]. Infrared, 2011(2):24-27.
[7]刘兴宝,袁道成.基于纹理分析的小波变换图像清晰度评价方法研究[J].仪器仪表学报, 2007(8):1508-1513.LIU Xingbao, YUAN Daocheng. Research on image definition criterion using wavelet transform based on the texture analysis[J]. Chinese Journal of Scientific Instrument, 2007(8):1508-1513.
[8]翟永平,周东翔,刘云辉,等.聚焦函数性能评价指标设计及最优函数选取[J].光学学报, 2011(4):242-252.DI Yongping, ZHOU Dongxiang, LIU Yunhui, et al. Design of evaluation index for auto-focusing function and optimal function selection[J]. Acta Optica Sinica, 2011(4):242-252.
[2]赵晨阳,冯浩,黄晓敏.红外测温技术在爆炸场温度测试中的精度研究[J].红外技术, 2014, 36(8):676-679.ZHAO Chenyang, FENG Hao, HUANG Xiaomin. Research on the precision of the infrared temperature-measuring technology in explosion fields temperature test[J]. Infrared Technology, 2014, 36(8):676-679.
[3]苏佳伟,石俊生,汪炜穑.距离对红外热像仪测温精度影响及提高精度的实验研究[J].红外技术, 2013, 35(9):587-590.SU Jiawei, SHI Junsheng. WANG Weise. Experimental study of infrared thermal imagers about influence of distance for temperature measurement accuracy and method of improving accuracy[J]. Infrared Technology, 2013, 35(9):587-590.
[4]郭帮辉,黄剑波,王志,等.目标距离和视场角变化对红外热像仪测温精度影响的理论分析[J].长春理工大学学报:自然科学版, 2011(1):16-19.GUO Banghui, HUANG Jianbo, WANG Zhi, et al. Analysis of effections on the precision of temperature measurement using infrared thermal imaging system with the change of object distance and field[J]. Journal of Changchun University of Technology:Natural Science Edition,2011(1):16-19.
[5]张健,杨立,刘慧开.环境高温物体对红外热像仪测温误差的影响[J].红外技术, 2005, 27(5):419-422.ZHANG Jian, YANG Li, LIU Huikai. Effect of environmental object on infrared temperature measurement[J]. Infrared Technology, 2005, 27(5):419-422.
[6]张勇,王新赛,贺明.距离对红外热像仪测温精度的影响及误差修正[J].红外, 2011(2):24-27.ZHANG Yong, WANG Xinsai, HE Ming. Influence of distance on temperature measurement accuracy of infrared thermal imager and error correction[J]. Infrared, 2011(2):24-27.
[7]刘兴宝,袁道成.基于纹理分析的小波变换图像清晰度评价方法研究[J].仪器仪表学报, 2007(8):1508-1513.LIU Xingbao, YUAN Daocheng. Research on image definition criterion using wavelet transform based on the texture analysis[J]. Chinese Journal of Scientific Instrument, 2007(8):1508-1513.
[8]翟永平,周东翔,刘云辉,等.聚焦函数性能评价指标设计及最优函数选取[J].光学学报, 2011(4):242-252.DI Yongping, ZHOU Dongxiang, LIU Yunhui, et al. Design of evaluation index for auto-focusing function and optimal function selection[J]. Acta Optica Sinica, 2011(4):242-252.