数字近景摄影测量辅助三维激光扫描用于森林固定样地测树原理探讨

近景摄影测量和近年来发展起来的三维激光扫描技术已广泛用于树木三维数据的获取,通过近景摄影测量技术和三维激光扫描方法获得的数据各有优缺点,但它们优势互补构成获取立木数据强大的工具。三维激光扫描有快速获取数据的优点,缺点是容易留下没扫描的空白区域（扫描漏洞）;摄影测量能根据人们的主观愿望布置测量控制网,很灵活地采集数据点,能够补充扫描漏洞没有数据点的缺陷,缺点是因布置测量控制网,要增加劳动强度,再者在影象上灰度变化不明显的部位无法获得同名像点,在一定程度上制约着三维建模的精度。试图探讨利用近景摄影测量辅助三维激光扫描的数据采集技术来恢复单木空间实体,计算胸径、任一处的直径、树高、树冠体积等测树指标,最后得出材积方程,服务于森林资源的精准监测。

Discussion on the Principles of Forest Measurement in Fixed Sample Plot with Three-D Laser Scanning Aided with Digital Close-range Photogrammetry

Close-range photogrammetry(CRP)and terrestrial laser scanning(TLS)increased in recent years have been used in the rapid acquisition of large volumes of 3-D data of trees.Data obtained by close-range photogrammetry or three-dimention laser scanning have their own advantages and disadvantages respectively.They complement one another and form a powerful tool for the creation of sample woods data.The method of three-dimension laser scanning data capture have the characteristics of capturing data quickly and its one of disadvantages is the margin left not to be scanned.While data points captured by close-range photogrammetry according to special purpose may compensate this disadvantage.A technology of data obtaining with three-D laser scanning aided with digital close-range photogrammery was discussed,by which the spatial entity of simple wood would be recovered and the index of forest surveying such as diameter at breast height,tree height and crown diameter.