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Feature Extraction with ENVI &
ENVI LiDAR
Remmy Kesis
Clifford Okembo
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Overview
Introduction
Feature Extraction from Imagery
Feature Extraction from LiDAR
Demos
Resources
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Author - share - use
Author
Share
Use
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Introduction
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Remote Sensing
Collecting information without being in physical contact
with an object
Sensor can be mounted on an Aircraft, Satellites, Vehicles
etc. (Platforms)
Can be from Active or
Passive Sensors
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Characteristics of a RS System
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Imagery
From different Sensors (e.g. SPOT, Landsat, MODIS) With different Resolutions (e.g. 1km, 30m, 50cm)
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Spatial Resolution
Low (e.g. MODIS-1km)
Medium (e.g. Landsat-30m)
High (e.g. SPOT 5-2.5m)
Very high (e.g. Pleiades -0.5m)
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What is Feature Extraction?
Process of finding and extracting specific objects ofinterest
Building Footprints
Roads network
Trees canopy
from Remotely Sensed data
Satellite Imagery
Aerial Photos LiDAR data
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Current Feature Extraction Methods
Supervised Classification
On-Board
Digitizing
On-screen/Heads-up
Digitizing
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Feature Extraction from Imagery
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What is ENVI?
Software for transforming imageryinto information
There is a lot of information
contained in imagery.
Imagery is essential for enabling
people to understand the world.
ENVI helps you extract
information quickly and easily
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The Complete Image Processing Platform
ENVI
The CompleteImage Processing
Platform
ENVI is the premier
application for extracting
geospatial information from
remotely-sensed imagery.
ENVI ACCESS Data Types
File Format Support
Sensor Support
Remote Data
Access
ANALYZE Visualizations
Data Prep & Registration
Spectral Classification
Feature Extraction
Change Detection
SHARE Geodatabases
Maps
Imagery
Publish
EXTEND
IDL, C++, Java,
.Net, C#
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Feature Extraction Workflow
ResultsWorkflow
Segmenting an image into regions
of pixels.
Computing attributes for each
region to create objects.
Classifying the objects by applying
rules.
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Rule Based Feature Extraction
Extracting specific features of interest using rules
Based on the following objects characteristics:
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ENVI Feature Extraction Module
Find and extract specific objects of interest from all typesof imagery.
Identify them as objects like vehicles, buildings, roads,
coastlines, rivers, lakes, and fields.
User-friendly tools
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ENVI Feature Extraction Module
You can modify parameters and data at any stage of the
process
Includes Unique step-by-step workflows simplifies
previously complex image analysis tasks
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Demo
Extract
With
ENVI FX
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Feature Extraction from LiDAR
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LiDAR
Combination of Light and RaDAR
Light Detection and Ranging
Operated at 532 to 1550
nm in EM spectrum
It is an Active Sensor
Data can be collected through
aerial, terrestrial, or mobile
methods
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How it Works
Measures distance by illuminating a target witha laser and analyzing the reflected light
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ENVI LiDAR
Software for Airborne LiDAR dataprocessing
Provides automatic solution for
point cloud data processing
Transforms geo-referenced point
clouds into GIS layers and 3D models
Processes large quantities of data
quickly
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Feature Extraction from LiDAR
1. DEM
2. DSM
3. Buildings
4. Power lines
5. Power poles
6. Trees
7. Contours
8. Photorealistic 3D
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Demo
Extract
With
ENVI LiDAR
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Resources
www.glovis.usgs.gov
laadsweb.nascom.nasa.gov/data/
http://www.astrium-geo.com/ http://exelisvis.com/ProductsServices/ENVIPr
oducts.aspx
http://www.glovis.usgs.gov/http://www.glovis.usgs.gov/http://www.laadsweb.nascom.nasa.gov/data/http://www.laadsweb.nascom.nasa.gov/data/http://www.astrium-geo.com/http://www.astrium-geo.com/http://www.astrium-geo.com/http://exelisvis.com/ProductsServices/ENVIProducts.aspxhttp://exelisvis.com/ProductsServices/ENVIProducts.aspxhttp://exelisvis.com/ProductsServices/ENVIProducts.aspxhttp://exelisvis.com/ProductsServices/ENVIProducts.aspxhttp://www.astrium-geo.com/http://www.laadsweb.nascom.nasa.gov/data/http://www.glovis.usgs.gov/ -
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Q/A