Fce 552 part6-4

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Transcript of Fce 552 part6-4

Dept. of Geospatial & Space Technology

University of NairobiB. Sc. (Civil Engineering)

1.1. Procedures of Image ProcessingProcedures of Image Processing

2.2. Image Processing SystemsImage Processing Systems

3.3. Digital Image Processing – CorrectionDigital Image Processing – Correction

4.4. Digital Image Processing – ConversionDigital Image Processing – Conversion

5.5. Digital Image Processing – ClassificationDigital Image Processing – Classification

FCE 552: Engineering Survey IV

Digital Image Processing

Dept. of Geospatial & Space Technology

University of NairobiEngineering Surveying IV

Procedures of Image Procedures of Image ProcessingProcessing

FCE 552: Engineering Survey IV

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Data Flow in Remote Sensing

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Data Processing in Remote Sensing

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Image Processing SystemsImage Processing Systems

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Image Processing Systems with Personal Computer

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Image Processing Systems with Network System

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Digital Image Processing - Digital Image Processing - CorrectionCorrection

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Due to variations in scene illumination and Due to variations in scene illumination and

viewing geometry, atmospheric conditions, viewing geometry, atmospheric conditions,

and sensor noise and response will vary and sensor noise and response will vary

depending on the specific sensor and depending on the specific sensor and

platform used to acquire the data and the platform used to acquire the data and the

conditions during data acquisition; conditions during data acquisition;

It may be desirable to convert and/or It may be desirable to convert and/or

calibrate the data to known (absolute) calibrate the data to known (absolute)

radiation or reflectance units to facilitate radiation or reflectance units to facilitate

comparison between data. comparison between data.

Radiometric Distortion

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Elements of Radiometric Correction

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Atmospheric Effects

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Atmospheric Correction

Dept. of Geospatial & Space Technology

University of Nairobi

Due to several factors, including: the Due to several factors, including: the

perspective of the sensor optics; the motion perspective of the sensor optics; the motion

of the scanning system; the motion of the of the scanning system; the motion of the

platform; the platform altitude, attitude, and platform; the platform altitude, attitude, and

velocity; the terrain relief; and, the velocity; the terrain relief; and, the

curvature and rotation of the Earth. curvature and rotation of the Earth.

To correct for these errors geometric To correct for these errors geometric

registration of the imagery to a known registration of the imagery to a known

ground coordinate system must be ground coordinate system must be

performed i.e., performed i.e., georeferencing.georeferencing.

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Geometric Distortions (1)

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Geometric Distortions (2)

Dept. of Geospatial & Space Technology

University of Nairobi

Flow of Geometric Correction

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Dept. of Geospatial & Space Technology

University of Nairobi

Relationship between Image andGround Control Systems

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Dept. of Geospatial & Space Technology

University of Nairobi

Example of Geometric Correction

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Digital Image Processing - Digital Image Processing - ConversionConversion

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Types of Image Conversion

Dept. of Geospatial & Space Technology

University of Nairobi

Image Enhancement – Grey Scale Conversion

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Dept. of Geospatial & Space Technology

University of Nairobi

Image Enhancement – Histogram Equalization

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Dept. of Geospatial & Space Technology

University of Nairobi

Image Enhancement - Color Composition

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Dept. of Geospatial & Space Technology

University of Nairobi

Feature Extraction - Spatial Filtering

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Dept. of Geospatial & Space Technology

University of Nairobi

Normalized Difference Vegetation Index

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Dept. of Geospatial & Space Technology

University of Nairobi

Principal Component Analysis

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

The objective is to

reduce the dimensionality

in the bands thus

maximizing the amount of

information from the

original data into the

least number of new

components.

Dept. of Geospatial & Space Technology

University of Nairobi

Principal Component Analysis

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Digital Image Processing - Digital Image Processing - ClassificationClassification

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Definition of Classification

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Concept of Classification

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Types of Classifications

Supervised classificationSupervised classification where the operator where the operator

defines the clusters during the defines the clusters during the training process training process

using training data obtained from using training data obtained from ground truthground truth..

Unsupervised classificationUnsupervised classification involves a involves a

clustering algorithmclustering algorithm automatically finding and automatically finding and

defining a number of clusters in the feature defining a number of clusters in the feature

space using only image characteristics or space using only image characteristics or

features.features.

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Features for Classification

Multi-spectral featuresMulti-spectral features

Multi-temporal featuresMulti-temporal features

TextureTexture

Height information (DTM/DEM)Height information (DTM/DEM)

Indices (e.g., NDVI)Indices (e.g., NDVI)

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Procedures of Classification

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Comparison between different classifiers

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Advanced Classifications

Fuzzy ClassificationFuzzy Classification

Contextual ClassificationContextual Classification

Artificial Neural Network ClassificationArtificial Neural Network Classification

Cognition-based ClassificationCognition-based Classification

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Recognition of Man-made Objects

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Example of Road Recognition

Dept. of Geospatial & Space Technology

University of Nairobi

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)

Example of Semi-automated Recognition of Houses

Dept. of Geospatial & Space Technology

University of Nairobi

Depending on the application, the information of Depending on the application, the information of

classes of interest need to be defined and their classes of interest need to be defined and their

spatio-temporal characteristics assessed. On the spatio-temporal characteristics assessed. On the

basis of these, the most appropriate data can be basis of these, the most appropriate data can be

selected and the criteria include:-selected and the criteria include:-

Sensor type (resolution, level of detail, etc).Sensor type (resolution, level of detail, etc).

Relevant wavelength bands.Relevant wavelength bands.

Date of acquisition (important for phenomena that are Date of acquisition (important for phenomena that are

time dependent, also considerations in regard to cloud time dependent, also considerations in regard to cloud

cover and amount of illumination should be taken into cover and amount of illumination should be taken into

account.account.

Budgetary Criteria.Budgetary Criteria.

Remote Sensing Data Selection Criteria

FCE 552: Engineering Survey IV

B. Sc. (Civil Engineering)