Semi Automatic Image Classification through Image Segmentation for Land Cover Classification Pacific GIS/RS Conference November 2013, Novotel Lami Vilisi Tokalauvere SPC/SOPAC

Outline  Why Semi-Automatic Image classification?  Tool Used  Problems  Process Framework  Some Preliminary Results

Land cover Mapping – 1:10,000 Enhanced Climate Change Resilience of Food Production Systems (SPC/USAID) WV2 – 8 Spectral bands Geo-eye 4 band multi-spectral

More detail – More time !

Imagine Objective Additional tool – ERDAS Imagine platform Feature extraction, update & Change Detection Produces data in a GIS format

Two Approaches

IMAGINE Objective Module for object-oriented geospatial image classification and discrete feature extraction Single Feature Probability (SFP) Pixel Classification A novel ERDAS invention applies discriminant analysis to multi-modal training data by distilling samples into Gaussian primitives Automatic background sampling

Initial Roadblocks Multi – class classification – Less resources available Whole satellite scene – time consuming Raw data 16bit– salt and pepper (8bit pan-sharpened) Experimentation with parameter values

First Results

IMAGINE Objective Architecture Process Framework Vector Objects (training) Vector Objects (candidates) TrainQuery Object Cue Metrics Object Inference Engine Raster Object To Raster Object Operator Pixel Probability Layer Raster Object Layer Vector Object Layer Raster Object Layer Raster Object To Vector Object Operator Vector Object To Vector Object Operator Vector Object Layer Vector Object Layer Prob.Pixels To Raster Object Operator Vector Object Layer Vector Object To Vector Object Operator Pixels (training) TrainQuery Pixel Inference Engine Pixels (candidates) Pixel Cue Metrics

Methodology Raster Pixel Processor (RPP) – Performed with Single Feature Probability and Multi – Bayesian Network – System training - Important

Methodology Raster Object Creators (ROC) – Raster Image Created - segmentation – Result – Thematic image

Methodology Raster Object Operators (ROO) – Size filter – Probability filter – Eliminating raster objects that do not meet criteria

Methodology Raster to Vector Conversion (RVC) – Raster object vectorised by ‘polygon trace’ – Polygons or Polylines produced Vector Object Operators – Reshaping the existing Vector Objects, eliminating vector objects that do not meet some criteria, combining multiple input vector objects into a single vector object, splitting vector objects into multiple new vector objects

Easy Editing

Vector Object Classification The Vector Object Processor (VOP) node performs classification on vector objects. Vector Cleanup Operators (VCO) allow the user to manipulate the Vector Objects after they have been processed by the Vector Object Processor.

Preliminary Results

Visual Interpretation after Segmentation

Vinaka