lecture#2 p2 interpretation

8/6/2019 LECTURE#2 P2 Interpretation

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1. INFORMATION EXTRACTION IN REMOTE SENSING

2. IMAGE INTERPRETATION

3. INTERPRETATION ELEMENTS/KEYS

Database Management Information System

& Applications of Remote sensing and GIS

Subject:

Dated:14/10/10Lecture#2-P2

Topics:

Presented

by

Rehana Jamal



1. INFORMATION EXTRACTION IN REMOTE SENSING

Remote sensing is the technology allowing to obtain information

of an object, area or phenomenon by means of data coming

from an apparatus, which is not in physical contact with this

object, area or phenomenon.

In practice, this means that the information of the Earth's surface

is obtained by sensors mounted on an airplane or a satellite.

Remote sensors record electromagnetic radiation emitted or

reflected from the Earth¶s surface. Different types of vegetation,

soils and other features emit and reflect energy differently.



*Energy Source or Illumination (A)

*Radiation and the Atmosphere (B

*Interaction with the Target (C)

*Recording of Energy by the Sensor (D)

*Transmission,Reception, and Processing (E)

*Interpretation and Analysis (F)

* Application (G

Process of

information

extractionfrom

remote

sensing



DIFFERENT TECHNIQUES OF INFORM ATION EXTR ACTION

Remote sensing:is a technique of

collecting

information from

a distance

Remotely sensed

data :

The data

collected from a

distance



³Remote Sensing (RS) is the science and

art of acquiring information (spectral,spatial, temporal) about material objects,

area, or phenomenon, without coming into

physical contact with the objects, or area,

or phenomenon under investigation³

Definitions of Remote Sensing

³Remote sensing is the science and art of

obtaining information about an object

,area or phenomenon through the

analysis of data acquired by a device that

is not in contact with the object, area or

phenomenon under investigation´

OR



Two main categories of Spatial data acquisition

Ground based methods

Remote sensing methods

Real world

Real world

Observation &

measurements

Spatial

database

Spatial

databaseObservation &

measurementsSensorsImage

data



Topic:2 Characteristics of Electromagnetic radiation

Electromagnetic Energy can be modelled in two ways

i. By waves ii. By Photons(Energy bearing particles)

Electromagnetic waves consist of a combination of oscillatingelectrical and magnetic fields, perpendicular to each other.



8

In respect to the type of Energy Resources:

Passive & Active remote Sensing



Stages in Remote Sensing

Source of energy

Interaction of EMR with the atmosphere

EMR interaction with Earth features

Detection of EMR by the remote sensing sensors

Data transmission and Processing

Image processing and analysis



ELECTRO

MAGNETIC

SPECTRUM



Image Interpretation´

Photographic Interpretation can be defined as:

³the act of examining photographic images for

the purpose of identifying objects and judging

their significance´ (Colwell, 1997).

Topic:2



Image Interpretation (visual analysis)

KALMA CHOWK,LAHORE



NEW CAMPUS(PU), LAHORE



Can you interpret CIMR in PU, Lahore?



Image Interpretation



Two methods of information extraction from

remote sensing imagery

Information extraction based on visual analysis or

interpretation of data e.g. land use, soil map,updating of topographic maps from aerial photographs

Information extraction based on semi-automatic

processing by computer e.g. automatic generation of

DTM, image classification and calculation of

surface parameters



Image understanding and Interpretation

1st Method

Human Vision

Interpretation elements

Stereoscopic vision



Direct and spontaneous recognition----refers to the

ability of an interpreter to identify objects or

phenomena at a first glance.

By a reasoning process (logical inference) ---In thereasoning interpreter will use his professional

knowledge & experience. If reasoning cannot help

then field observation is required

Two situations of human vision:

i. Direct and spontaneous recognition

ii By a reasoning process(logical inference)

1- Human Vision



refers to the ability of an interpreter to identify

objects or phenomena at a first glance.

i- Direct and spontaneous recognition---



LAHORE



� In the reasoning, interpreter will use hisprofessional knowledge & experience.

� If reasoning cannot help then field observation is

required

ii- By a reasoning process (logical inference) ---



LAHORE



³A set of terms required to express and define characteristics

present in pictures (that are visualized in image data) are called

Interpretation elements.´ e.g.

Tone/Hue Texture

Shape

Size

Pattern

Site Association

2- Interpretation elements



Tone/Hue--- relative brightness of black and white image

Texture--- refers to the colour on the image as defined in the Intensity, Hue

,Saturation(HIS)system

Shape--- form characteristics many terrain objects visible in the image

Size--- relative or absolute

Pattern--- refers to the spatial arrangement objects e.g. concentric, radial---

irrigation and housing have different pattern

Site--- relates to the topographic or geographic location

Association--- refers to the fact that a combination of objects makes it

possible to infer about its meaning or functioning

2- Interpretation elements



Radar image interpretation



The impression of depth in real world can be realized by the pair

of images of the same object taken from different positions. Such a

pair of images, photographs or digital images that are separated and

observed at the same time by the two eyes give images on the

retinas in which objects at different positions in space are projectedon relative different positions. This is called Stereoscopic Vision

Stereo grams---Pairs of images that can be viewed

stereoscopically are called Stereo grams.

Convergence---Focusing both eyes to the object(point) of interest

is called convergence.

3- Stereoscopic Vision



Pocket and Mirror stereoscopes--- use a system of

lenses &mirrors to feed one image into one eye

uses: in vegetation, forest, soil, and geomorphology

Photogrammetric plotters---uses: in topographic &large

scale mapping activities

Anaglyph system---

Corresponding spectacles comprising one Red

one Green glass suited to view overlappingimages on a computer screen.

In digital photogrammetric system polarization is

also applied.

Different Methods of Stereoscopic Vision



Pocket stereoscope with original test image.Used by military to

examine stereoscopic pairs of vertical aerial photographs.

Pocket and Mirror stereoscope



Photogrammetric plotters



Anachrome optical diopter glasses.

Anachrome "compatible" color anaglyph method



Anaglyphs



Stereoscopic Vision and 3D Technology



Process of visual image interpretation

Selection of image data and its hard copy prints

Use of transparencies to overlay on hard copy print of

image for interpretation

Digitization of line patterns on transparencies having class

codes & land cover codes.

Validation: independent assessment of accuracy



Applications of visual image interpretation

Soil mapping with aerial photographs

Land cover mapping from multispectral data

Some general aspects i.e. Geometric aspects (size & width)

of objects)and Classes or categories of objects by using

hierarchical system



Land cover & Land use

Land cover ---refers to the type of features present

on the surface of the land,e.g., water, sand, potato

crop & asphalt.

Land use ---refers to the human activity or economic

function for a specific piece of land, e.g., urban use ,

industrial use, agricultural use or nature reserve.



The aim of the European Union¶s CORINE Land Cover project is to

provide up to date information on land cover at scale 1:100,000 for the

whole Europe.

The database includes 44 categories in accordance with a standard

European nomenclature, organised into five large groups:artificial surfaces, agricultural areas, forest and semi-natural areas,

wetlands, water bodies.

Classification was done by visual interpretation using Landsat

ThematicMapper satellite image maps with the help of topographicmaps as main ancillary material and field work. Following digitization the

land cover information is stored in topological structure as ARC/INFO

database.

Objective of CORINE



CORINE LAND COVER map sheet no.54.



Requirement of image based mapping process

Field observations can be used:

to gather local knowledge

to gather data about areas or features that are

hidden due to DEAD GROUND effect

validation(evaluation of final evaluation result) or accuracy is determined



DEAD GROUND EFFECT



Quality aspects

Professional experience and image interpretation

experience

Image data applied limit the phenomena

Quality of the interpretation guidelines



References:

�www.google.com

�³Principles of Remote sensing´

by Lucas L.E. Janssen

�http://fish.fomi.hu/angolfish/adathaz/

termekek/CORINE/corine.htm

lecture#2 p2 interpretation

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