Abstract:The present paper investigates the quantitative relationship between the NDVI and SAVI vegetation indices of Landsat and ASTER sensors based on three tandem image pairs. The study examines how well ASTER sensor vegetation observations replicate ETM+ vegetation observations, and more importantly, the difference in the vegetation observations between the two sensors. The DN values of the three image pairs were first converted to at-sensor reflectance to reduce radiometric differences between two sensors,images. The NDVI and SAVI vegetation indices of the two sensors were then calculated using the converted reflectance. The quantitative relationship was revealed through regression analysis on the scatter plots of the vegetation index values of the two sensors. The models for the conversion between the two sensors,vegetation indices were also obtained from the regression. The results show that the difference does exist between the two sensors,vegetation indices though they have a very strong positive linear relationship. The study found that the red and near infrared measurements differ between the two sensors, with ASTER generally producing higher reflectance in the red band and lower reflectance in the near infrared band than the ETM+ sensor. This results in the ASTER sensor producing lower spectral vegetation index measurements, for the same target, than ETM+. The relative spectral response function differences in the red and near infrared bands between the two sensors are believed to be the main factor contributing to their differences in vegetation index measurements, because the red and near infrared relative spectral response features of the ASTER sensor overlap the vegetation “red edge” spectral region. The obtained conversion models have high accuracy with a RMSE less than 0.04 for both sensors’ inter-conversion between corresponding vegetation indices.
Key words:NDVI;SAVI;Cross comparison;ASTER;ETM+;Spectral response function
[1] Dinguirard M, Slater P N. Remote Sensing of Environment, 1999, 68(3): 194. [2] Chander G, Markham B. IEEE Transactions on Geoscience and Remote Sensing, 2003, 41(11): 2674. [3] Chander G, Meyer D J, Helder D L. IEEE Transactions on Geoscience and Remote Sensing, 2004, 42(12): 2821. [4] Teillet P M, Barker J L, Markham B L. Remote Sensing of Environment, 2001, 78: 39. [5] Thome K J. Remote Sensing of Environment, 2001, 78: 27. [6] Thome K J, Biggar S F, Wisniewski W. IEEE Transactions on Geoscience and Remote Sensing, 2003, 41(6): 1180. [7] Steven M D, Malthus T J, Xu H, et al. Remote Sensing of Environment, 2003, 88(4): 412. [8] Thenkabail P S. International Journal of Remote Sensing, 2004, 25(2): 389. [9] Goward S N, Davis P E, Fleming D, et al. Remote Sensing of Environment, 2003, 88(1): 80. [10] Soudani K, Francois C, Maire G, et al. Remote Sensing of Environment, 2006, 102(2): 161. [11] LIU Liang-ming, LIANG Yi-tong, MA Hui-yun, et al(刘良明, 梁益同, 马慧云, 等). Geomatics and Information Science of Wuhan University(武汉大学学报·信息科学版), 2004, 28(4): 307. [12] Van Leeuwen W J D, Orr B J, Marsh S E, et al. Remote Sensing of Environment, 2006, 100(1): 67. [13] CHEN La, HUANG Jing-feng, WANG Xiu-zhen(陈 拉, 黄敬峰, 王秀珍). Journal of Remote Sensing(遥感学报), 2009, 12(1): 143. [14] Miura T, Yoshioka H, Fujiwara K, et al. Sensors, 2008, 8: 2480. [15] Irish R. Landsat 7 Science Data Users handbook. http://ltpwww.gsfc.nasa.gov/ias/handbook/handbook_toc.html, 2010. [16] Abrams M, Hook S, Ramachandram B. ASTER User Handbook, Version 2. http://asterweb.jpl.nasa.gov/documents/aster_user_guide_v2.pdf, 2010. [17] Chander G, Xiong X, Choi T, et al. Remote Sensing of Environment, 2010, 114: 925. [18] CHEN Zheng-chao, LIU Xiang, LI Jun-sheng, et al(陈正超,刘 翔,李俊生, 等). Journal of Astronautics(宇航学报), 2008, 29(2): 247. [19] XU Han-qiu(徐涵秋). Geomatics and Information Science of Wuhan University(武汉大学学报·信息科学版), 2007, 32(1): 62. [20] Chavez P S, jr. Photogrammetric Engineering and Remote Sensing, 1996, 62(9): 1025. [21] Huete A R. Remote Sensing of Environment, 1988, 25: 295. [22] JIANG Jin-bao, CHEN Yun-hao, HUANG Wen-jiang(蒋金豹, 陈云浩, 黄文江). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2010, 30(6): 1614.