用针叶和阔叶树冠的观测数据对树冠断层成象算法的验证(英文)

王锦地; 李小文; 项月琴

doi:CNKI:SUN:YGXB.0.1997-S1-010

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用针叶和阔叶树冠的观测数据对树冠断层成象算法的验证(英文)
TCT Algorithm Validation Using Measurement Data of Coniferous and Deciduous Crowns
1997年第S1期
纸质出版日期： 1997 ，
DOI： CNKI:SUN:YGXB.0.1997-S1-010

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[1]王锦地,李小文,项月琴.用针叶和阔叶树冠的观测数据对树冠断层成象算法的验证(英文)[J].遥感学报,1997(S1):70-78.

Wang Jindi, Li Xiaowen. TCT Algorithm Validation Using Measurement Data of Coniferous and Deciduous Crowns[J]. Journal of Remote Sensing, 1997,(S1).
[1]王锦地,李小文,项月琴.用针叶和阔叶树冠的观测数据对树冠断层成象算法的验证(英文)[J].遥感学报,1997(S1):70-78. DOI： CNKI:SUN:YGXB.0.1997-S1-010.

Wang Jindi, Li Xiaowen. TCT Algorithm Validation Using Measurement Data of Coniferous and Deciduous Crowns[J]. Journal of Remote Sensing, 1997,(S1). DOI： CNKI:SUN:YGXB.0.1997-S1-010.

摘要

在植被ＢＲＤＦ模型及其应用研究中，我们发展了一种树冠结构参数的间接测量方法。称为“树冠断层成象法（ＴＣＴ）”，可获取树冠内叶面倾角分布（ＬＡＤ），叶面积体密度的空间分布（ＦＡＶＤ）和叶面积指数（ＬＡＩ）。文中论述对该方法的进一步发展，利用实测的针、阔叶树冠数据对ＴＣＴ方法的验证。为了克服前文中所述的问题，我们研制了树冠断层象底视数据采集系统（ＴＣＴＳ），获取树冠的多视点底视图象。该系统由便携式微机，图象数字化板，可见光／近红外广角摄象机及其支架导轨，图象监示器组成。摄取图象可实时数字化存于计算机硬盘，并可实时监视图象采集质量。摄象机支架和导轨可控制摄象机身的姿态，并保证其在地面给定水平方向的连续移动。我们选择针叶和阔叶两种树种进行算法验证，设计进行了多次野外的多视点底视图象采集，并同期进行手工的树冠结构参数测量，包括树冠形状和叶面积体密度。ＴＣＴ方法的改进主要有：１)提取了图象采集过程中天空光的分布，作为从图象中推算方向间隙率的参考量。２)将用单张广角图象提取的叶角分布（ＬＡＤ）引入ＴＣＴ算法。３)利用近红外图象可区分枝干和叶丛，以提高ＦＡＶＤ重构的可靠性，并可区分全植被植数（ＴＰＡＩ）和ＬＡＩ。该文论述如?

Abstract

In our vegetation BRDF model and its application studies

we developed an indirect measuring method named the Tree Computed Tomography （TCT） for gathering tree crown architecture parameters

which include the Leaf Angle Distribution （LAD）

Foliage Area Volume Density （FAVD）

and Leaf Area Index （LAI）.  With direct method in field

it is difficulty to measure this kinds of architecture parameters

especially for trees. The TCT algorithm combining both computed tomography theory and vegetation canopy gap probability model

makes the indirect method be possible in tree crown architecture measurement. To improve and validate the algorithm

the Tree Computed Tomography field data gathering System（TCTS） was designed for getting more reliable multiviewing points image set in field. Both coniferous and deciduous crowns were selected to do indirect and manual direct measurement to get crown architecture parameters for the validation.  To improve our TCT algorithm

the average skylight distribution during the multiviewing points data gathering is reconstructed

the LAD estimation is considered

and the trunk/branches information is taken into account of FAVD reconstruction. Comparing the reconstructed 3d FAVD and manual measurement data

the results show that the reconstructed FAVD fit the manual measurement data very well. Then these indirect measured crown architecture parameters and measured radiance of lighted crown had been used in our BRDF model studies. This paper presents the above approach and the validation results.