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AUTOMATIC TARGET RECOGNITION OF CIVILIAN TARGETS. September 28 th , 2004 Bala Lakshminarayanan. Objective Introduction to ATR Details of SFTB Database creation Segmentation Feature extraction, classification Results Conclusions. Outline. Civilian target classification
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AUTOMATIC TARGET RECOGNITION OF CIVILIAN TARGETS September 28th, 2004 Bala Lakshminarayanan
Objective Introduction to ATR Details of SFTB Database creation Segmentation Feature extraction, classification Results Conclusions Outline
Civilian target classification Sensor fusion SFTB objectives - Generation of dataset for ATR - Ground truth data collection Objective
What is ATR Why do we need it Types of ATR - Aided, unaided - Binary, multi-valued Problems Introduction to ATR
Requirements - Real time operation - Low false positives - High detection rates Applications - Military - Medical - Industrial Introduction to ATR
Nodes - Base station - 2 with IR sensor - 1 with visible light sensor Node placement Targets (cars, light trucks, SUVs) Ground truth collection equipment Scenarios SFTB
SFTB Image provided by Night vision lab
Fully exposed targets except by other presence on scene Stationary sensors Daylight operation License plates not readable Constant velocity/acceleration Different scenarios (3) Simultaneous data capture SFTB
Images Node 1 Node 3 Node 2
Use IR and visual images to classify targets Use sensor fusion to improve accuracy Creation of image database Creation of framework Segmentation, feature extraction, classification Project Objective
Images in .arf files Use frames captured at same time “Event start” - Range from Node2 = 20 “Event end” - Outside FoV of Node3 Database Creation
Framework Inputs-nodeID, scenario… Start Grab frame from dataset filename() Segment bgSubtract(), motionDet() Extract features invMoment() Classify readData(), knn() End
Used to identify the target/RoI in the frame Methods - Thresholding - Background subtraction - Motion based segmentation Segmentation
Background subtraction median(frame)-median(background) Noise removal by neighbourhood() Segmentation - = - =
Motion based segmentation temp1=average(prev)-average(frame) temp2=average(next)-average(frame) temp1&temp2 Segmentation
Features should describe similar targets similarly Seven invariant moments (Hu, 1962) Computed from central moments, third order Translational invariance – C.G Distance invariance – Size normalization Feature Extraction
Feature Extraction Central moments Normalized moments 1 = 20 + 02, 2= (20 - 02)2 + 4211 3 = (30 - 312)2 + (03 - 321)2, 4 = (30 + 12)2 + (03 + 21)2 5 = (330 - 312)(30 + 12)[(30 + 12)2 –3(21 + 03)2] + (321 - 03)(21 + 03) [3(30 + 12)2 – (21 + 03)2] 6 = (20 - 02)[(30 + 12)2 – (21 + 03)2] + 411(30 + 12)(21 + 03) 7= (321 - 03)(30 + 12)[(30 + 12)2 - 3(21 + 03)2] + (312 - 30)(21 + 03) [3(30 + 12)2 – (21 + 30)2]
Supervised or unsupervised k-nearest neighbour method Training vectors are given Find k nearest neighbours, maximum presence Classification
3 classes - 1, 2, 4; single scenario 7 features - 5 training vectors, 2 testing vectors k = 1, 3 Results
Overall classification results k=1 – 58.33% k=3 – 50% Target1 – 25% Target2 – 38.5% Target4 – 100% Results
Confusion matrix Results
Database created Basic framework has been laid Robust segmentation needed More training vectors Segmentation does not work for px files Conclusions
Segmentation - Quadtree based split-merge - Use of Kalman filters - Histogram based segmentation Better features need to be used Future work
Thanks ?? and !!