模糊數學分類法應用於Landsat-TM衛星影像上林分鬱閉度推估之研究

A Study of Estimation Forest Canopy Closure through Fuzzy Classification of Landsat TM Data

王韻皓(Yon-Hao Wang) ； 焦國模(Kwo-Mu Chiao)

《航測及遙測學刊》 2卷4期 (1997/12) Pp. 1-12

https://doi.org/10.6574/JPRS.1997.2(4).1

摘要

林分鬱閉度為生態研究及森林經營管理上一重要之指標，除了與土壤沖刷、水源涵養、國土保安有密切之關係，還可用來評估野生動物棲息地及森林生物量等。早期林分鬱閉度之判釋，多利用航空照片，但1972年大地衛星（Landsat-1）發射後，由於植物於光譜中有吸收藍光、紅光，強烈反射紅外光之特性，因此利用遙測影像之光譜資訊推估林分鬱閉度已廣為各界研究。本研究係以臺大實驗林溪頭營林區1-6林班為試區，並以大地衛星主題測繪儀（Landsat TM）影像為分析之材料。首先將Landsat TM影像做前期處理，包括幾何及輻射糾正，經前期處理後之影像選取3*3像元之柳杉純林樣區72個，擷取TM影像單波段（TM1-TM5、TM7）、纓帽轉換式（綠度軸，GVI）、歸整差（NDVI）、植被比（R43、R54、R32）、植生指標差（VI43、VI45、VI42）等14個植生指標，於72個樣區中選取41個訓練樣區，以此植生指標做為模糊分析與最小距離法之輸入資料，推估林分鬱閉度，並利用31個檢核樣區，做準確度之評估，比較此兩種分類方法之結果。

並列摘要

Forest canopy closure is an important index on ecological study and forest management. Forest canopy closure is closely related to erosion control, water and soil conservation, watershed runoff estimation, which is also used to assess wildlife habitat and forest biomass. In the early years, aerial photography were usually used to interprete forest canopy closure. However, after the launch of Landsat-1 in 1972, using remote sensing image to estimate forest canopy closure is widely studied. The study area of this research locates at Chi-Tou, Experimental Forest of National Taiwan University. A Landsat Thematic Mapper scene of this area was used in the study.In this study, geometric correction and radiometric correction were done first to improve the quality of the TM imagery. After preprocessing, seventy-two plots with a size of 3*3 pixels were drawn from the TM imagery. Fourteen vegetation indices TM1、 TM2、TM3、TM4、TM5、TM7、GVI、NDVI、R43、R54、R32、VI43、VI45、VI42. Those indices were used as input data for the fuzzy classification approach and the minimum distance pattern classification approach to estimate forest canopy closure, and the results of these two approaches were compared.