Aerial Mapping & Modeling using UAV www.verticalaspect.com - - PowerPoint PPT Presentation

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Aerial Mapping & Modeling using UAV www.verticalaspect.com - - PowerPoint PPT Presentation

Jul 14, 2023 118 likes •621 views

Aerial Mapping & Modeling using UAV www.verticalaspect.com support@verticalaspect.com 1 (202) 494-8410 1 Vertical Aspect Services Aerial mapping Aerial Imagery Pix4D Software Premium Reseller Training UAV

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Aerial Mapping & Modeling using UAV

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www.verticalaspect.com support@verticalaspect.com (202) 494-8410

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Vertical Aspect

  • Services

– Aerial mapping – Aerial Imagery

  • Pix4D Software

– Premium Reseller – Training

  • UAV Training
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Mapping Theory / Techniques / Products

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Graphical Map

BENEFITS:

  • Good for navigation
  • Inexpensive to produce
  • Easy to interpret
  • Non-technical
  • No underlying data
  • Not to scale / no accurate

measurements

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Orthomosaic Map

BENEFITS:

  • Referenced to real world location
  • Enables accurate measurements
  • Rectified to 3D information
  • Graphical representation of

underlying data

  • Underlying data easily exported /

converted

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UAV photogrammetry

  • Efficient for Small areas
  • Affordable / Accurate maps

Survey efficiency with respect to Survey area

Changing the mapping game

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Ground Control Points (GCP)

Ground Control Points (GCP)

  • Well distributed in dataset
  • Visible on multiple images
  • 5-8 sufficient for up to 1000 images
  • Quality report shows reprojection error

Obtaining GCPs

  • Traditional Survey Methods
  • RTK GPS device
  • Less accurate
  • Google Earth
  • Smartphone App
  • Handheld GPS device
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Without GCP

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With GCP

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Mapping Output & Potential Market

  • Output

– Orthomosaic – 3D Point Cloud – Topographic – Digital Surface Model

  • Potential Customers
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Output types

https://support.pix4d.com/hc/en- us/articles/202561399-Example-Datasets-Available- for-Download-Cadastre-

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3D Models

  • Digital Surface Model

– Everything

  • Digital Terrain Model

– “Bare Earth” – Used by engineers

  • Oblique Models
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Unclassified 3D Point Cloud

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Classified Point Cloud-Terrain

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Classified Point Cloud - Objects

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Digital Surface Model (with scale)

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Contour Lines

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Contour Lines – (terrain only)

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Planar vs. Orthomosaic

(Photo Stitching) (Orthorectification)

  • Works only if terrain perfectly

flat

  • Only small datasets supported

(due to error accumulation)

  • No good georeference without

GCP

  • Distances (measurements) not

accurate

  • Requires only low number of

matches / keypoints (>100)

  • Handles any terrain type
  • Handles large datasets
  • Supports Georeference

perfectly

  • Preserves distances &

becomes measurable

  • Requires high number of

matches/keypoints (>1000) to generate the 3D model

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Accurate Measurements

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Stockpile Volume Calculations

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UAV Image Capture

Fixed Wing & Multirotor

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Plan & Load the mission Fly – Capture images Process, Provide Output

Workflow

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Fixed Wing vs. Multirotor

Fixed Wing

  • 1. Larger area
  • 2. Larger takeoff /

landing area

  • 3. Higher Altitudes / less

detail

  • 4. Longer Flight Time
  • 5. More expensive

Multirotor

  • 1. Smaller area
  • 2. VTOL – much smaller

takeoff / landing area

  • 3. Lower altitudes /

greater detail

  • 4. Shorter Flight Times
  • 5. Lower cost of entry
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3D Flythrough Video

(Press “Play” Key to View Video) or view at https://www.youtube.com/watch?v=oDEIT1xvWyw

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Fixed Wing vs. Multirotor

Larger Area, less resolution Smaller Area, higher resolution

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Digitized Orthomosaic

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Generated Files

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Methods of Capturing Images

  • Fixed Wing

– SenseFly eBee – eMotion flight planning / capture

  • Multirotor

– DJI Phantom Vision 2 + – Pix4D Capture App

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Image Overlap

  • High accuracy results
  • Requires high overlap

between images

  • Consistent altitude
  • Recommended Overlap
  • Frontal - >75%
  • (with respect to flight

direction)

  • Side - >60%
  • (between flight tracks)

Frontal overlap > 75% Side overlap > 60%

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Camera Considerations

  • Megapixel size less important than image
  • verlap
  • Sensor size determines area of coverage at

given altitude

  • Automated Flight Path necessary for reliability

& accuracy

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Safety Considerations

  • Autonomous Flight Required for proper data collection
  • DO’s

– Fly within Line of Sight – Remain below 400’ AGL and outside of controlled airspace – Use spotter to handle people, have them keep their distance during takeoff and landing – Be prepared to take control of aircraft if autonomous flight fails – Give yourself a cushion on battery level

  • BE PREPARED

– For the possibility of the aircraft losing power – Fixed wing – more options & less weight than multirotor

  • DO NOT

– Fly linearly over major roads

  • Cross them at right angles

– Allow people to distract you during flight – Fly over crowds of people

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Sample Fixed Wing Capture (SenseFly eBee)

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Sample eBee Mapping Flight

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Post Flight Processing

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Image Transfer

  • Transfer to tablet

– Annotates images with more accurate GPS geotags – Creates .p4d file

  • Upload to PC for processing

– Pix4D cloud (initial quality check) & later retrieval) – Dropbox – Manual transfer

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Field Reporting (Optional)

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Initial Processing

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Quality Report

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Initial Point Cloud

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Ray Cloud

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Densified Point Cloud

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Mosaic Mesh – Initial

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Mosaic Mesh – Reset

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Mosaic - Blended

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Contour and DSM

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Google Earth & Pix4D

Google Earth Pix4D Overlay

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Questions?

Jeff Campbell (202) 494-8410 www.verticalaspect.com

  • r e-mail us at

support@verticalaspect.com