TY - JOUR A1 - Zhang, Y. A1 - Zhang, Y. A1 - Zhang, Y. A1 - Li, X. T1 - AUTOMATIC EXTRACTION OF DTM FROM LOW RESOLUTION DSM BY TWOSTEPS SEMI-GLOBAL FILTERING JO - ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci. J1 - ISPRS-Annals VL - III-3 SP - 249 EP - 255 Y1 - 2016/06/03 PB - Copernicus Publications SN - 2194-9050 UR - https://isprs-annals.copernicus.org/articles/III-3/249/2016/ L1 - https://isprs-annals.copernicus.org/articles/III-3/249/2016/isprs-annals-III-3-249-2016.pdf DO - 10.5194/isprs-annals-III-3-249-2016 ER -