• Acta Optica Sinica
  • Vol. 43, Issue 11, 1112002 (2023)
Zongtao Duan1, Jian Zhang1、2、3、*, Guoyu Zhang1、2、3, Yangyang Zou4, Zhengjie Niu1, Bin Zhao1, Xiaoxu Mo1, Zhikun Yun1, Jianliang Zhang5, and Jia Guo6
Author Affiliations
  • 1School of Opto-Electronic Engineering, Changchun University of Science and Technology, Changchun 130022, Jilin, China
  • 2Jilin Photoelectric Measurement and Control Instrument Engineering Technology Research Center, Changchun 130022, Jilin, China
  • 3Key Laboratory of Optoelectronic Measurement and Control and Optical Information Transmission Technology, Ministry of Education, Changchun 130022, Jilin, China
  • 4College of Instrumentation & Electrical Engineering, Jilin University, Changchun 130012, Jilin, China
  • 5Air Force Aviation University, Changchun 130022, Jilin, China
  • 6Changchun Wanyi Technology Application Co., Ltd., Changchun 130022, Jilin, China
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    DOI: 10.3788/AOS222179 Cite this Article Set citation alerts
    Zongtao Duan, Jian Zhang, Guoyu Zhang, Yangyang Zou, Zhengjie Niu, Bin Zhao, Xiaoxu Mo, Zhikun Yun, Jianliang Zhang, Jia Guo. Measurement of Reflected Light Field of Rough Surfaces Using Ultrawide-angle Imaging[J]. Acta Optica Sinica, 2023, 43(11): 1112002 Copy Citation Text show less

    Abstract

    Objective

    The reflected light field information of a rough surface includes the reflected light angle and intensity, which can be used to retrieve the reflection and morphology characteristics of the surface. Therefore, accurate measurement of the reflected light field has high research value and practical applications in the fields of target detection and recognition, in-orbit radiation calibration, material property analysis, optical device stray light analysis, etc. Presently, the traditional "scanning" method uses a mechanical mechanism to achieve point-by-point scanning measurement of the spatial reflected light field information of the target sample; however, there are problems such as slow measurement efficiency, numerous measurement error links, and poor repeatability. Furthermore, given the influence of incident light wavelength and energy fluctuation on the measured data during the scanning process, the weight gradually increases with increasing time, which may lead to distortion of full-space BRDF fusion information. In contrast, the emerging "photographic" measurement method based on optical imaging techniques only measures the reflected light field in a small angle range. In this study, to overcome the low efficiency of the "scanning" reflected light field measurement system and the small measuring angle range of the "photographic" reflected light field measurement system, a rough surface reflected light field measurement method based on ultrawide-angle imaging is proposed. This method realizes the measurement of multidirectional angle reflected light field information over a large angle range, enriches measurement means of rough surface reflected light fields and is suitable for measuring optical reflection characteristics and damage of material surface. Here, the simulation and reconstruction provide a research basis and technical support.

    Methods

    Based on the principle of reflected light field measurement, this paper first determined the overall structure of the reflected light field measurement system, which comprises a light source, sample plate to be measured, a hemispherical reflecting ball screen, and a refractive reflecting ultrawide-angle imaging optical system. Next, the catadioptric ultrawide-angle imaging optical system was optimized and the best resolution angle in the optical system's field of view was simulated and analyzed. Subsequently, a calibration method for the reflected light field measurement system was studied to realize off-axis spatial position calibration and light field intensity calibration. Finally, the reflected light field measurement results were simulated and analyzed using a Labsphere Permaflect-80 diffuse reflector, WhiteOptics-DF60 diffuse reflector, and American ACA specular aluminum plate, proving the feasibility of the proposed surface reflected light field measurement method.

    Results and Discussions

    The best resolution angle of the designed reflected light field measurement system is 2° in the range of 0°-54° zenith angle and 15° in the range of 0°-360° azimuth angle (Fig. 9). The coordinate distribution of the feature points after calibration was obtained using the off-axis spatial position mapping relationship (Fig. 11); the relative error of light field measurement increases with increasing zenith angle. The maximum relative error in the range of the measuring field of view is 4.12% at the zenith angle of 54° and azimuth angle of 255°. The maximum average relative error is 2.06% and the average relative error is less than 1% within the range of 0°-36° zenith angle (Fig. 14). The measurement results were obtained using the Labsphere Permaflect-80 diffuse reflective plate, WhiteOptics-DF60 diffuse reflective plate, and ACA specular aluminum plate of the United States under conditions of uniform illumination using a 550-nm incident beam with a zenith angle of 40° and azimuth angle of 270°(Fig.16). The results show that the surface of specular aluminum material with rough surfaces have strong specular reflection characteristics, which is consistent with the reflection characteristics of the material itself (Fig.17).

    Conclusions

    Based on the principle of ultrawide-angle imaging, a reflective light field measurement system has been successfully designed here that achieves a best angle resolution of 15° in the azimuth range of 0°–360° and a best angle resolution of 2° in the zenith range of 0°-54°. After calibration, the maximum average relative error of the circumference under each zenith angle is 2.06%. These results support that the "photographic" method of measuring a reflected light field can also be used to measure a reflected light field in a large angle range using a reasonable optical system design.

    Zongtao Duan, Jian Zhang, Guoyu Zhang, Yangyang Zou, Zhengjie Niu, Bin Zhao, Xiaoxu Mo, Zhikun Yun, Jianliang Zhang, Jia Guo. Measurement of Reflected Light Field of Rough Surfaces Using Ultrawide-angle Imaging[J]. Acta Optica Sinica, 2023, 43(11): 1112002
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