Improvements in airborne scanning technology boost productivity

Author: Linda Duffy

通过改进的扫描功能和功能，满足了对空中激光雷达的需求增加，这些功能在更少的时间内会在较大的区域上产生密集的点云。As an early adopter of scanning technology, Woolpert, the fastest-growing architecture, engineering and geospatial (AEG) firm in the US, has owned and operated every product in Leica Geosystems’ LiDAR series since the ALS40 was released in 2002. Woolpert purchased its first Leica TerrainMapper in early 2019 and has since acquired three more. Today, the TerrainMapper is Woolpert’s preferred technology for large area mapping and difficult terrain, including Department of Transportation (DOT) projects and federal programs such as the United States Geological Survey (USGS) 3D Elevation Program (3DEP).

海拔数据的需求

Aerial LiDAR data is a valuable source of information for many applications, such as 3D urban modelling, infrastructure development, coastal and natural hazard monitoring, and environmental conservation. Efforts are underway to establish a current national LiDAR dataset, and there are numerous local and regional entities investing in LiDAR coverage as well.

对密度和准确性的期望不断提高，以符合激光雷达传感器的增强功能。在Leica TerrainMapper的释放中，性能的增量改进是一种线性模式传感器的释放，该传感器允许在较高高度收集非常密集的点云，从而大大减少了采集时间。

伍尔珀特（Woolpert）的副总裁兼地理空间部门负责人约瑟夫·塞普（Joseph Seppi）说：“有了大面积的映射，效率确实会得到回报。”“我们的项目可以超过30,000平方英里，甚至超过100,000平方英里，因此能够以更快的速度飞行的能力使TerrainMapper成为非常有效的选择。”

TerrainMapper能够在300米（M）至5,500 m之间的飞行高度上收集LiDAR，并在飞行高度达到2公里（km）处提供USGS LIDAR质量0（QL0）数据。这种出色的效率水平非常适合更大的区域或国家地图项目，在该项目中，运营成本对更新频率产生重大影响。

开会并超过规格

Every project has minimum data requirements depending on the intended application. For example, USGS QL1 data must be at least 8 points per square metre (ppsm) with a Root Mean Square Error (RMSE) not exceeding 10.0 centimetres (cm). Other criteria may include leaf-off, no snow, no standing water, and no rain. In temperate climates, deciduous trees and snow are obstacles. In tropical and subtropical climates, clouds and rain are often a problem. Due to challenging conditions in many geographic areas, efficient data collection during limited flying windows is crucial for getting the job done.

2019年,怀俄明运输部(WYDOT) contracted with Woolpert to map three landslide areas along a 10-mile stretch of the Continental Divide in northwest Wyoming, close to Yellowstone National Park. Woolpert collected LiDAR at 50 ppsm and colourised the point cloud with imagery collected simultaneously with the integrated Leica RCD30 aerial camera. The final digital terrain models (DTMs) and triangulated irregular network (TIN) models provided WYDOT with a baseline to determine the slide movement, volume and rate at which the earth is moving over time. WYDOT performed an independent check and compared over 120 individual point cloud elevations from field collected points. The average elevation difference of 3.6 cm exceeded the requested 5 cm vertical accuracy.

TerrainMapper还被证明在线性公用事业项目和通行通行权方面有效，并成功地测量了高架电源线的下垂。即使飞行速度比其他传感器更高，地形室也返回各种项目的必要点密度。

“In high relief terrain we achieve greater efficiency by flying higher without adjusting to as many different altitudes,” Seppi stated. “And for utility work, it is safer to fly at a high altitude far above the lines, with the added benefit of capturing more of the surrounding area.”

伍尔珀特（Woolpert）在2019年与TerrainMapper一起在各个州飞行了10多个USGS项目。在佛罗里达州和俄亥俄州等州，尽管天气状况，但高速批量的集合在一个飞行季节内完成了映射项目。

塞皮继续说：“某些地方的天气可能具有挑战性，使我们的工作时间更少，因此TerrainMapper的大量收集能力有助于我们快速完成该项目并保持一致性。”“此外，该传感器的点分布，模式和出色的强度回报对许多特征提取用途非常有益。”

This zoomed-in contour map shows features such as pavement, pipes, and a culvert near Wind River Lake.

Acquisition and processing integration

后处理工作流程是效率影响整体项目成本的另一个领域。Woolpert使用Leica HXMAP多传感器处理平台，该平台旨在简化TerrainMapper数据的处理。HXMAP的过程，校准和注册发光点云，同时处理图像传感器数据并颜色点云。在HXMAP的帮助下，Woolpert提供了完全处理的分类点云，这些云符合严格的项目规格，以确保准确性和密度。

Seppi说：“ HXMAP使我们能够更加敏捷，并随时适应变化。”“当我们有关键的截止日期时，我们可以轻松地转移处理以从其他项目分配HXMAP资源。HXMAP就像一个黑匣子，它会自动在幕后执行其作品。”

HXMAP专为使用TerrainMapper数据而设计，它利用集成的扫描仪/相机系统的优点来生成一个单个接口中的所有空中数据产品。亚搏彩票手机版下载HXMAP提供嵌入式空中三角剖分，并为大型倾斜成像项目，全国矫正项目以及大型或小型激光雷达项目提供解决方案。

The Wyoming Department of Transportation translated the lidar data provided by Woolpert into a variety of graphics, including a digital terrain model of the area near Wind River Lake.

连续的提高

Leica TerrainMapper是在非常成功的ALS80系列之后的下一代激光雷达传感器。传感器系统提高数据收集速率与飞行高度，改善飞行计划，并实现偶数分布。增强的生产率节省了时间和金钱，而较高的脉搏率，更高的激光功率和无元技术则有助于更高的点密度。

塞皮说：“莉卡·地理系统的传感器一直在变得更好。”“从ALS80的TerrainMapper的表现跃升非常重要。我们发现圆形扫描模式具有很大的优势，例如线到线的校准和音高调整。飞行更高，更快地提高了我们的效率200-400％。自1989年以来，Leica Ge亚搏彩票手机版下载osystems产品一直是我们传感器机队的骨干。”

对3D激光雷达数据的需求正在上升，这使得及时获取和处理越来越重要。从数据下载到产品生成，TerrainMapper与HXMAP工作流程的紧密集成使整个过程都加快了整个过程，以支持每个映射项目的更快周转。