超光谱成像仪的实验室辐射定标
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摘要
超光谱成像仪是一种定量获取景物图像与光谱信息的新一代光学遥感仪器,高分辨率超光谱成像仪以较高的地面分辨率获取目标的光谱图像数据。但是实际工作中,超光谱成像仪所获取的图像不仅与景物光谱及辐射亮度相关,同时也受大气散射、透过率、光学系统的衰减、光电成像转化效率以及电子学系统等其他因素影响,其输出的图像在层次和幅度对比关系上将与真实景物的辐射亮度图像产生严重的偏差,于是对超光谱成像仪进行完善的定标实验及其获得的高精度定标成果是完成各种高质量定量化遥感产品处理、支持产品定量化应用的基础。通过实验室辐射定标可以检测遥感仪器主要性能指标,获取辐射定标基本参数,初步建立图像反演公式。
本文分析和总结了超光谱成像仪实验室辐射定标的意义和背景,介绍了辐射定标的概念、分类、内容以及实现方法,总结超光谱成像仪定标原理;针对超光谱成像仪的原理、特点以及定标内容的要求,提出具有可实施性的定标方法和步骤,完成了超光谱成像仪的实验室辐射定标,描述了超光谱成像仪的辐射特性。
根据不同太阳高度角和地面反射率确定超光谱成像仪不同的工作模式,用积分球模拟不同模式下的典型辐射亮度,对超光谱成像仪不同谱段进行了辐射定标,包括绝对辐射系数定标、动态范围、响应非均匀性、非线性度、信噪比,得出各像元的绝对辐射响应度、光电响应的线性拟合曲线方程,以及均匀性校正系数,最后分析了引起辐射定标误差的来源,确定了辐射定标精度。
实验表明超光谱成像仪PAN谱段在960码以内可严格保证响应线性,通过非均匀性校正可使得非均匀性从10%降低到0.3%左右,在典型工作条件下,积分时间为0.35ms时也可保证信噪比在380以上;对于VNIR谱段,当DN响应达到3900时,复合相关系数R2仍为0.9999,说明VNIR谱段具有较大的线性动态范围,通过校正,非均匀性可降低一倍左右。
Hyper-spectrum imager is an optical instrument that obtains images and spectral information at one time. This High Resolving capability Hyper- Spectrum Imager(HRHSI) obtains spectral image information with a high resolving power of ground. But practically, the information that imager obtained is not only related with the action spectrum and radiate luminance, but also influenced by atmospheric dispersion, permeate rate, attenuation and photoelectric transform rate of optic system and electric system. Due to these factors, the original digital image acquired by hyper-spectrum imager is different from radiance image of real target. So mature calibration is necessary, and the accurate calibrated results are foundation of processing and application of a variety of high quality quantitative analysis of remote sensor products. By laboratory radiometric calibration, we check the main performance indicators of remote sensors, obtain the basic parameters of radiometric calibration, and establish the image inversion formula.
This thesis analyzed and summarized the significance and background to develop laboratory radiometric calibration, introduced the conception, sorts, contents and methods of radiometric calibration, summarized the calibration theory of HRHSI. To the question of the theory and characteristic of HRHSI, brought forward enforceable method and steps of calibration, accomplished laboratory radiometric calibration, described radiate characteristics of HRHSI.
The integration sphere is used for simulating different radiance, which is decided by the different sun vertex angle and different reflectivity of the ground. The HRHSI is calibrated in lab, including absolute radiometric coefficient, dynamic range, photo response non-uniformity, Non-Linearity and Signal-to-Noise(SNR). Then absolute radiate response of each pixel, linear curve of photoelectric response and non-uniformity correction coefficients are obtained. At last uncertainty of calibration is discussed.
The result shows that PAN of HRHSI is strictly linear within 960. After non-uniformity correction, non- uniformity will reduce from 10% to 0.3%. In the typical condition, SNR should be 380 at least, although integral time is 0.35ms.
本文分析和总结了超光谱成像仪实验室辐射定标的意义和背景,介绍了辐射定标的概念、分类、内容以及实现方法,总结超光谱成像仪定标原理;针对超光谱成像仪的原理、特点以及定标内容的要求,提出具有可实施性的定标方法和步骤,完成了超光谱成像仪的实验室辐射定标,描述了超光谱成像仪的辐射特性。
根据不同太阳高度角和地面反射率确定超光谱成像仪不同的工作模式,用积分球模拟不同模式下的典型辐射亮度,对超光谱成像仪不同谱段进行了辐射定标,包括绝对辐射系数定标、动态范围、响应非均匀性、非线性度、信噪比,得出各像元的绝对辐射响应度、光电响应的线性拟合曲线方程,以及均匀性校正系数,最后分析了引起辐射定标误差的来源,确定了辐射定标精度。
实验表明超光谱成像仪PAN谱段在960码以内可严格保证响应线性,通过非均匀性校正可使得非均匀性从10%降低到0.3%左右,在典型工作条件下,积分时间为0.35ms时也可保证信噪比在380以上;对于VNIR谱段,当DN响应达到3900时,复合相关系数R2仍为0.9999,说明VNIR谱段具有较大的线性动态范围,通过校正,非均匀性可降低一倍左右。
Hyper-spectrum imager is an optical instrument that obtains images and spectral information at one time. This High Resolving capability Hyper- Spectrum Imager(HRHSI) obtains spectral image information with a high resolving power of ground. But practically, the information that imager obtained is not only related with the action spectrum and radiate luminance, but also influenced by atmospheric dispersion, permeate rate, attenuation and photoelectric transform rate of optic system and electric system. Due to these factors, the original digital image acquired by hyper-spectrum imager is different from radiance image of real target. So mature calibration is necessary, and the accurate calibrated results are foundation of processing and application of a variety of high quality quantitative analysis of remote sensor products. By laboratory radiometric calibration, we check the main performance indicators of remote sensors, obtain the basic parameters of radiometric calibration, and establish the image inversion formula.
This thesis analyzed and summarized the significance and background to develop laboratory radiometric calibration, introduced the conception, sorts, contents and methods of radiometric calibration, summarized the calibration theory of HRHSI. To the question of the theory and characteristic of HRHSI, brought forward enforceable method and steps of calibration, accomplished laboratory radiometric calibration, described radiate characteristics of HRHSI.
The integration sphere is used for simulating different radiance, which is decided by the different sun vertex angle and different reflectivity of the ground. The HRHSI is calibrated in lab, including absolute radiometric coefficient, dynamic range, photo response non-uniformity, Non-Linearity and Signal-to-Noise(SNR). Then absolute radiate response of each pixel, linear curve of photoelectric response and non-uniformity correction coefficients are obtained. At last uncertainty of calibration is discussed.
The result shows that PAN of HRHSI is strictly linear within 960. After non-uniformity correction, non- uniformity will reduce from 10% to 0.3%. In the typical condition, SNR should be 380 at least, although integral time is 0.35ms.
引文
[1]钱乐样等.遥感数字影像处理与地理特征提取[M].北京:科学出版社,2004.
[2]陈署.遥感系统的光谱辐射定标[J].?遥感信息,1990,000(010).
[3]冯家璋,崔敦杰,杨华元等.中国昼光光谱测定装置[J].太阳能学报,1991,12(4):427.
[4]黄润.遥感信息系统研究[M].北京:科学出版社,2000.6.
[5]奕中杰.线阵CCD光电参量测试系统的研究[J].光学精密工程,1994,2(4):140-149.
[6] Peter Jarecke and Karen Yokoyama. Radiometric Calibration Transfer Chain from Primary Standards to the End-to-End Hyperion Sensor[J]. Proceedings of SPIE Vol. 4135 (SPIE, 2004,Bellingham, WA,):254-263.?
[7] James M. Palmer and Philip N. Slater. A ratioing radiometer for use with a solar diffuser[J]. SPIE,1991,Vol. 1493.?
[8]崔敦杰.成像光谱仪的定标[J].遥感技术与应用,1996,11(3):57-63.
[9]王斌永,舒嵘,贾建军,等.无人机载小型多光谱成像仪的设计[J].光学与光电技术,2004,2(2):18-20.
[10]高海亮,顾行发,余涛,等.超光谱成像仪在轨辐射定标及不确定度分析[J].光子学报,2009,38(11):2826-2833.
[11]刘银年,薛永祺. 64波段机载光谱成像仪[J].红外与毫米波学报,2002,21(1):9-14.
[12] Blechinger F et al. High Resolution Imaging Spectrometer HRIS[J], Optics,Focal Plane and Calibration. SPIE,1993,1937: 207~224.?
[13] PALMER J M,SLATER P N. A ratioing radiometer for use with a solar diffuser[J]. SPIE,1991,1493:106-117.?
[14] ROCKEY D E. High Resolution Imaging Spectrometer(HIRIS): a major advance in imaging spectrometry[J]. SPIE,1990,1298:93-104.?
[15] XIONG X , CHIANG K , ESPOSITO J , et al. MODIS on-orbit calibration and characterization[J]. Metrologia,2003,40:89-92.?
[16] XIONG X,SUNA J,ESPOSITO J,et al. MODIS reflective solar band calibration algorithm and on-orbit performance[J]. SPIE,2002,4891:95-104.?
[17] BARRY P,SEGAL C,PEARLMAN J,et al. Hyperion data collection: performance assessment and science application[C]. IEEE,Aerospace Conference Proceedings,California,USA,2002.?
[18] JARECKE P,YOKOYAMA K,BARRY P. On-orbit solar radiometric calibration of theHyperion instrument[J]. SPIE,2002,4480:225-230.?
[19] BLECHINGER F,CHARLTON D E,DAVANCENSR,et al. High resolution imaging spectrometer“HRIS”optics,focal plane and calibration[J]. SPIE,1993,1937:207-224.?
[20] HARNISCH B,KUNKEL B,SAINT-PE O,et al. HRIS technology development results and their implementation in future hyperspectral imagers[J]. SPIE,1997,3221:396-411.
[21] BAUD N G , MATIHEW S , BESSUDO R , et al. Medium Resolution Imaging Spectrometer(MERIS) calibration sequence[J]. SPIE,1996,2819:141-240.
[22] OLIJ C,SCHAARSBERG J G,WERIJ H,et al. Spectralon diffuser calibration for MERIS[J]. SPIE,1997,3221:63-74.
[23] LABAND BAR J Y,BAUD N G,BALLION Y. ALCATEL-SPACE in hyper/multispectral earth observation programmes,from MERIS to SPECTRA[J]. SPIE,2004,5234:232-242.
[24] Zimmerman G,et al. MOS/PRIRODA-An Imaging VIS/NIR Spectrometer for Ocean Remote Sensing. SPIE,1993,1937:201-206.?
[25] CUTTER M A,LOBB D R,WILLIAMS T L,et al. Integration & testing the Compact high-Resolution Imaging Spectrometer(CHRIS)[J]. SPIE,1999,3753:180-191.
[26] XIONG X,SUN J,BARNES W. MODIS on orbit characterization using the moon[J]. SPIE,2002,4881:299-307.
[27] QU J J,BAO W,KAFATOSM,et al. Earth Science Satellite Remote Sensing,Volume 2[M]. Beijing:Tsinghua University Press,2006.
[28]田媛,赵丽巍,等.声光可调谐滤光片作为电热原子吸收光谱仪波长选择器的研究[J].高等学校化学学报,Vol.23,No.1,38-41.
[29] T.G.Chrien,C.Chovit. Imaging spectrometer using a liquid crystal tunable filter[J]. SPIE,1993,1937:92-101.
[30]杜培胜,郭靖,等.液晶可调谐滤光片及其在光谱仪上的应用.红外,2007,Vol.28:No.11,4-8.
[31]范滨,李刚正,等.线性渐变滤光片的制备与测试.光学仪器,Vol.28,No4:95~103.
[32]蒋月娟,李全臣.成像光谱技术的新发展.光电子技术与信息,Vol.13,No4:26-29.
[33]吴瑾光.近代傅里叶变换红外光谱技术及应用.北京:科学技术文献出版社,1994:16-19.
[34]范东栋,王建岗,邬敏贤.用于遥感光谱探测的反射成像光谱技术.航天返回与遥感,2001,Vol.22,No.4:52~57.
[35]姜景山.空间科学与应用[M].北京:科学出版社,2001.
[36]崔敦杰.光学遥感器的辐射定标纪念建所五十周年论文及论文摘要汇编(一)[C].长春:长春光学精密机械与物理研究所,2002:148-154.
[2]陈署.遥感系统的光谱辐射定标[J].?遥感信息,1990,000(010).
[3]冯家璋,崔敦杰,杨华元等.中国昼光光谱测定装置[J].太阳能学报,1991,12(4):427.
[4]黄润.遥感信息系统研究[M].北京:科学出版社,2000.6.
[5]奕中杰.线阵CCD光电参量测试系统的研究[J].光学精密工程,1994,2(4):140-149.
[6] Peter Jarecke and Karen Yokoyama. Radiometric Calibration Transfer Chain from Primary Standards to the End-to-End Hyperion Sensor[J]. Proceedings of SPIE Vol. 4135 (SPIE, 2004,Bellingham, WA,):254-263.?
[7] James M. Palmer and Philip N. Slater. A ratioing radiometer for use with a solar diffuser[J]. SPIE,1991,Vol. 1493.?
[8]崔敦杰.成像光谱仪的定标[J].遥感技术与应用,1996,11(3):57-63.
[9]王斌永,舒嵘,贾建军,等.无人机载小型多光谱成像仪的设计[J].光学与光电技术,2004,2(2):18-20.
[10]高海亮,顾行发,余涛,等.超光谱成像仪在轨辐射定标及不确定度分析[J].光子学报,2009,38(11):2826-2833.
[11]刘银年,薛永祺. 64波段机载光谱成像仪[J].红外与毫米波学报,2002,21(1):9-14.
[12] Blechinger F et al. High Resolution Imaging Spectrometer HRIS[J], Optics,Focal Plane and Calibration. SPIE,1993,1937: 207~224.?
[13] PALMER J M,SLATER P N. A ratioing radiometer for use with a solar diffuser[J]. SPIE,1991,1493:106-117.?
[14] ROCKEY D E. High Resolution Imaging Spectrometer(HIRIS): a major advance in imaging spectrometry[J]. SPIE,1990,1298:93-104.?
[15] XIONG X , CHIANG K , ESPOSITO J , et al. MODIS on-orbit calibration and characterization[J]. Metrologia,2003,40:89-92.?
[16] XIONG X,SUNA J,ESPOSITO J,et al. MODIS reflective solar band calibration algorithm and on-orbit performance[J]. SPIE,2002,4891:95-104.?
[17] BARRY P,SEGAL C,PEARLMAN J,et al. Hyperion data collection: performance assessment and science application[C]. IEEE,Aerospace Conference Proceedings,California,USA,2002.?
[18] JARECKE P,YOKOYAMA K,BARRY P. On-orbit solar radiometric calibration of theHyperion instrument[J]. SPIE,2002,4480:225-230.?
[19] BLECHINGER F,CHARLTON D E,DAVANCENSR,et al. High resolution imaging spectrometer“HRIS”optics,focal plane and calibration[J]. SPIE,1993,1937:207-224.?
[20] HARNISCH B,KUNKEL B,SAINT-PE O,et al. HRIS technology development results and their implementation in future hyperspectral imagers[J]. SPIE,1997,3221:396-411.
[21] BAUD N G , MATIHEW S , BESSUDO R , et al. Medium Resolution Imaging Spectrometer(MERIS) calibration sequence[J]. SPIE,1996,2819:141-240.
[22] OLIJ C,SCHAARSBERG J G,WERIJ H,et al. Spectralon diffuser calibration for MERIS[J]. SPIE,1997,3221:63-74.
[23] LABAND BAR J Y,BAUD N G,BALLION Y. ALCATEL-SPACE in hyper/multispectral earth observation programmes,from MERIS to SPECTRA[J]. SPIE,2004,5234:232-242.
[24] Zimmerman G,et al. MOS/PRIRODA-An Imaging VIS/NIR Spectrometer for Ocean Remote Sensing. SPIE,1993,1937:201-206.?
[25] CUTTER M A,LOBB D R,WILLIAMS T L,et al. Integration & testing the Compact high-Resolution Imaging Spectrometer(CHRIS)[J]. SPIE,1999,3753:180-191.
[26] XIONG X,SUN J,BARNES W. MODIS on orbit characterization using the moon[J]. SPIE,2002,4881:299-307.
[27] QU J J,BAO W,KAFATOSM,et al. Earth Science Satellite Remote Sensing,Volume 2[M]. Beijing:Tsinghua University Press,2006.
[28]田媛,赵丽巍,等.声光可调谐滤光片作为电热原子吸收光谱仪波长选择器的研究[J].高等学校化学学报,Vol.23,No.1,38-41.
[29] T.G.Chrien,C.Chovit. Imaging spectrometer using a liquid crystal tunable filter[J]. SPIE,1993,1937:92-101.
[30]杜培胜,郭靖,等.液晶可调谐滤光片及其在光谱仪上的应用.红外,2007,Vol.28:No.11,4-8.
[31]范滨,李刚正,等.线性渐变滤光片的制备与测试.光学仪器,Vol.28,No4:95~103.
[32]蒋月娟,李全臣.成像光谱技术的新发展.光电子技术与信息,Vol.13,No4:26-29.
[33]吴瑾光.近代傅里叶变换红外光谱技术及应用.北京:科学技术文献出版社,1994:16-19.
[34]范东栋,王建岗,邬敏贤.用于遥感光谱探测的反射成像光谱技术.航天返回与遥感,2001,Vol.22,No.4:52~57.
[35]姜景山.空间科学与应用[M].北京:科学出版社,2001.
[36]崔敦杰.光学遥感器的辐射定标纪念建所五十周年论文及论文摘要汇编(一)[C].长春:长春光学精密机械与物理研究所,2002:148-154.