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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