ASTER感測器之第三光譜波段使用推掃式立體成像系統,有別於其他採用本體旋轉組成同軌或跨軌立體成像模式之衛星;並且具有高B/H值,有利於數值高程模型的產製。ASTER影像空間解析度15公尺,預估相對數值高程之精度約為十至三十公尺。本研究採用九份二山地區一幅ASTER影像,取其第三波段之立體像對產製數值高程模型,並與已知之數值高程模型進行比較,藉以評估其產製數值高程模型之精度。由測試區精度評估結果可發現當影像因雲等外在因素或匹配失敗地區的影響下,相對與絕對DSM與以航空攝影測量產製之參考數值高程模型相較,高程較差均方根值最大可達±414m;惟當無上述等影響下絕對DSM高程較差均方根值僅±11.87m。
The third band of ASTER sensor provides along track stereo capability. Two images are collected in this band and one looking nadir, one looking backward. Based on the height-base ratio and the 15 meters spatial resolution of the ASTER sensor, the error of the relative DSM generated with the ASTER stereo-pair is expected to range from 10 meter to 30 meters. This study investigates the DEM accuracy with one ASTER scene in the Jeou-Fen-Erh-San area. It is found that the standard deviation is ±11.87m for areas without clouds or other unfavorable factors.