Geiger Mode LiDAR the Next Paradigm for Floodplain Management

Transcription

1 Geiger Mode LiDAR the Next Paradigm for Floodplain Management ASFPM 2015 Mark E. Romano Geospatial Product Manager harris.com 1

2 Geiger-mode (GmAPD) LiDAR sensor Geiger-mode GmAPD LiDAR Sensor Built specifically for wide-area, high-density collection 2

3 FAQ s Is Geiger Mode LiDAR a new technology? No - it been utilized successfully in the defense industry for over 15 years. It is only new to the commercial industry. Why hasn t it been available before now? Key components could not be sourced for commercial application until recently Are Geiger Mode LiDAR data noisy? Yes But - in its raw (unprocessed) state it is noisier than linear systems however, this just means a different approach to processing is utilized to produce elevation data and derivative products. Does Geiger Mode LiDAR work in daylight conditions? Yes Commercial Geiger mode technology is designed to work in daylight (solar) conditions with a minimal decrease in performance. Years of proven performance in real world operations and applications 3

4 High Power Low Sensitivity Approximately 500KHz sample Rate for single scanner designs 4

5 Low Power High Sensitivity 200MHz vs. 500KHz 5

6 Collection Simulation Comparison (8ppm) Higher Faster Greater Resolution 6

7 Collection 8PPM 17X Efficiency gains keep costs down at higher collection densities 7

8 Collection Cost Reduced Cost at Higher Resolutions Linear Systems Geiger-mode Collection Density (points per square meter) Higher the resolution greater the payback 8

9 So, Why do higher densities matter? Infrastructure details better defined 2 pts/m 2 8 pts/m 2 20 pts/m 2 Improves: Terrain accuracy Obscure object detection 2 pts/m 2 8 pts/m 2 20 pts/m 2 Higher resolving power and improved FOPEN 9

10 What makes Geiger Mode so Different Geiger-mode sensors sample the same spot on the ground thousands of times 10

11 How Does it Work? Avalanche Photo Diode Array (4096 detectors) Photon counting device (Low light sensitivity enables use of low power laser ) Capable of sub-ns operation (enables higher vertical measurement precision and vertical resolution) Supports high laser Pulse Repetition Frequencies (PRF) GmAPD Camera Uses 32x128 Flash Array Think of it as a 3D camera 11

12 GmAPD Multi-Look/Multi-Pulse Collection Multi-look approach 4096 measurements per laser flash 50,000 flashes per second Approx= 205 million elevation measurement per second Every spot illuminated 1000 s of times The dozens of photon detections are processed to determine the real objects Programmable Forward/Sidelap 12

13 Linear Technology Limitations Inefficient and costly at high resolutions Has inherent data occlusions Foliage penetration is limited by single sample approach Limited-range resolution (target separation) Limitations with single sample/look systems 13

14 Single Look Linear Artifact Example1 Shadows (occlusions) from linear scanners Occlusions due to single look angle 14

15 Single Look Linear Artifact Example 2 Vegetation Shadows (occlusions) from linear scanners Limited FOPEN due to single look angle NON-Export Controlled Information 15

16 Single Look Linear Artifact Example 3 Compression/Expansion effect from linear scanners Lack of homogeneity due to varying groundspeed 16

17 Solution multi-look and Oversampling 17

18 Multi-Look and Oversampling Linear Geiger Mode Reduces Artifacts and occlusions Provides Highly Homogenous High-Density Accurate Data 18

19 Reflectance Image Linear Geiger Mode Increases Detail Provides Highly Homogenous High-Density Accurate Data 19

20 High Resolution& Accuracy Result 20

21 High Resolution& Accuracy Result 21

22 What can I use this data for? Pre-access where risk may be present Automated risk analysis such as HAG,s, LAG s, and others 22

23 River Overbank 10ft Rise 23

24 Barrier Island 10ft Rise 24

25 River Bank 10ft rise 25

26 Improving Accuracy Results Aggregating multi-look data requires highly accuracy alignment Required Inputs: Utilize latest INS/GPS Utilize horizontal and vertical GPS ground control objects Opposing 50% overlap sorties create four looks (fore/aft <>fore/aft) Process: Perform H/V bundle adjustment via GPS tie points Perform auto tie point registration from multiple look angles True photogrammetric bundle adjustment provides higher accuracy 26

27 Accuracy Improves with Rigorous Bundle Adjustment Multi-Swath Alignment via Sensor Based 3D Photogrammetric Bundle Adjustment Enables Rigorous Accuracy Statements per Point Sensor-based adjustment enables per point accuracy statements 27

28 How we Deal With all This data Not for the workstation environment in raw form Terabytes - Petabytes in data management and processing Requires high-speed, distributed, multi-core processing Sorties are processed in <24 hours Total solution requires innovation in both hardware and software Over 15 years of evolution Increased automation is critical for reducing production cost/time 28

29 Automated GmAPD LiDAR Processing Ground Processing Workflow Point Cloud Processing Data Finishing Preprocessing & Calibration Sensor ToF Data Pointing Data GPS/INS Data Flight Logs Point Cloud Generation Sensor Based Swath Registration Noise Filter Single Swaths Point Cloud Generation Match Point Filter Noise Filter Cross Swath Aggregate Intermediate Point Clouds Final Product Hydro Enforcement Clean Up QC Analysis QC Products Point Cloud Auto Classification QC Graphic & Metric Generation Point Cloud Products Attributed LAS L4 Point Cloud (PC3) QC Products GeoTIFF & PNG Anomaly Mask Interpretation Mask Height Map Control Ground Survey Manual Registration Aggregate Chips to Ground Survey Batch Gridding, Re-Tile & Format Raster Products GeoTIFF L4 Intensity Image (RII) L4 Reflective Surface (DSM) L4 Bare Earth Surface (DTM) Ingest & Project Setup Data Management & Archive Outcome - Manageable solution for the customer 29

30 Summary of Benefits Dramatically improves speed of collection (Schedule) Lower cost for higher quality (Value) Improves foliage penetration (Better DTM s) Multi-look reduces shadows/voids (artifacts) Higher accuracy with robust bundle adjustment Improved flood model base elevation data and structures Higher quality at lower cost for improved analysis 30

31 Questions? Examples from new Harris commercial Geiger Mode LiDAR 31