Development and Development and Implementation of a FPGA-based Implementation of a FPGA-based
digital beamformerdigital beamformer
Supervisors:Supervisors: Nandita BhattacharjeeNandita Bhattacharjee Dr. Andrew PaplinskiDr. Andrew Paplinski
Dale Harders
Presentation OutlinePresentation Outline
– An Ultrasonic Imaging System OverviewAn Ultrasonic Imaging System Overview
– Beamforming FundamentalsBeamforming Fundamentals
– Significance of studySignificance of study
– Simulator role within this projectSimulator role within this project
– ImplementationImplementation
Dale Harders
Ultrasonic Imaging System OverviewUltrasonic Imaging System Overview
Dale Harders
Spatial FilterSpatial Filter- Only extract desired Only extract desired directionaldirectional data data- Remaining signals are attenuatedRemaining signals are attenuated
Beamforming FundamentalsBeamforming Fundamentals
What is a beamformer?What is a beamformer?
Dale Harders
Focussing subsystemFocussing subsystem- Electronic vs. MechanicalElectronic vs. Mechanical- Sharper images are producedSharper images are produced
Beamforming FundamentalsBeamforming Fundamentals
Consider how an ultrasonic imaging system operatesConsider how an ultrasonic imaging system operates
Dale Harders
How is this focussing achieved digitally?How is this focussing achieved digitally?
Beamforming FundamentalsBeamforming Fundamentals
Possible SolutionPossible Solution:: Delay in time Delay in time
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DisadvantagesDisadvantages:: Large storage requirements Large storage requirements High clock rates required for fine delaysHigh clock rates required for fine delays
A rotation of complex data in the frequency A rotation of complex data in the frequency domain is equivalent to a time delay in the time domain is equivalent to a time delay in the time domain.domain.
Beamforming FundamentalsBeamforming Fundamentals
Better SolutionBetter Solution:: Phase-shiftPhase-shift via complex vector rotation via complex vector rotation
Dale Harders
Process data in a different DomainProcess data in a different Domain- requires Quadrature sampling (Re, Im)requires Quadrature sampling (Re, Im)
AdvantagesAdvantages:: Relatively small digital circuitry required Relatively small digital circuitry required Lower sampling rates requiredLower sampling rates required
Significance of StudySignificance of Study
Increase Image ResolutionIncrease Image Resolution - Improve Signal-to-noise ratio- Improve Signal-to-noise ratio
Maintain fast frame-ratesMaintain fast frame-rates - Real-time imaging- Real-time imaging
Develop 3D-imaging techniquesDevelop 3D-imaging techniques
Ultimate GoalsUltimate Goals
Dale Harders
Continuation of Previous Research @ MonashContinuation of Previous Research @ Monash- (Hampson G, 1998), (Bhattacharjee et al, 2000)(Hampson G, 1998), (Bhattacharjee et al, 2000)
- (Prain R, 2001)(Prain R, 2001)
Simulator role within this projectSimulator role within this project
Ultrasound simulation programUltrasound simulation program - Developed by Joergen Jensen, DenmarkDeveloped by Joergen Jensen, Denmark - Running under MatlabRunning under Matlab
Capable of emulating Capable of emulating allall sub-systems sub-systems
Field IIField II
Dale Harders
(Jensen, 1996)
Simulator role within this projectSimulator role within this project
Field II ExampleField II Example Origin
0-x +x0
+z
Dale Harders
Simulator role within this projectSimulator role within this project
Field II ExampleField II Example
Dale Harders
Simulator role within this projectSimulator role within this project
Field II ExampleField II ExampleOrigin
Dale HardersDale Harders
ImplementationImplementation
Dale HardersDale Harders
Hardware systemHardware system- Two word-parallel, fully pipelined, CORDIC vector rotators Two word-parallel, fully pipelined, CORDIC vector rotators
operating in paralleloperating in parallel- Summing performed on chipSumming performed on chip
Design implemented on a Design implemented on a XilinxXilinx Spartan IISpartan II FPGA FPGA
Device DriverDevice Driver- Interfaced PCI communications API to MatlabInterfaced PCI communications API to Matlab
Developed System - Block Schematic Next Slide…
Beamformer SystemBeamformer System
ACCUMULATOR
ConclusionConclusion
Dale HardersDale Harders
Stable Development Platform builtStable Development Platform built- Easy to use interface for new design test-benchingEasy to use interface for new design test-benching
PCI communicationsPCI communications - Developed a PCI communications interface between Matlab Developed a PCI communications interface between Matlab
and the Hardware for design verification and future and the Hardware for design verification and future
development accelerationdevelopment acceleration
Project deliverables satisfiedProject deliverables satisfied- Successfully implemented a hardware digital beamformerSuccessfully implemented a hardware digital beamformer
References
Bhattacharjee N, Paplinski A and Hampson G, "Phase-shift Beamforming", TR 2000/53, CSSE , Monash
University, Clayton, 2000
Hampson G.A, "Implementing Multi-Dimensional Digital Hardware
Beamformers", PhD thesis, Faculty of Computing andInformation Technology. Monash University, Clayton,1998.
Jensen J.A, "Field: A program for simulating ultrasound systems",
10th Nordic-Baltic Conference on Biomedical Imaging,vol 4, pg 351-353, 1996.
Prain R, “Parallel CORDIC implementation for hardware
beamformers”, Honours Thesis, Department of CSSE, Monash University, Clayton, 2001. Dale Harders