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Reconfigurable FPGAs for USCT

N.V. Ruiter, M. Balzer, M. Hübner, Institut für Prozessdatenverarbeitung und Elektronik, FZKInstitut für Technik der Informationsverarbeitung, Uni Ka

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Ultrasound Computer Tomography

Basic idea: Surround object with (unfocussed) transducers in fixed setup

Research for nearly 30 years

Long term goal: Early breast cancer diagnosis

Most frequent cancer for womenHigh death tollEarly detection = good survival probability

Possible advantages USCT:Higher image quality, volume imagesNon ionizing for screeningReproducibleMore than one image modality

Example data recording (in 2D)

Workshop on Novel Trends and Approaches in Algorithmand Hardware-Architectures for Image Reconstruction Applications 2009

Breast imaging in fixed setup

Transmission

Reflection

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Specification of Our System

Surround object in 3D3D unfocussed transducers

Advantages:Optimal focus in 3DFast data acquisition possible

Challenges:Low Signal to Noise Ratio (SNR)Limited number of transducers (sparse aperture)Very demanding reconstruction

3D USCT

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Currents Systems

3D USCT ICylindrical aperture1920 transducers (12 000 pos)3.5 Mio A-Scans ~ 20 GB

Proof of concept with static phantoms

3D USCT IIOptimized semi-ellipsoidal apertureRotation and TranslationPowerful DAQ hardware: 20s -2.5 min

Imaging of living tissue

Visit USCT Lab

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Digital Signal and Image Processing

Signal pre-processing

Signal processing

Image reconstruction

• Averaging• Digital Bandpass• Matched filter, e.g. Chirps•…

• Signal detection• Detection of

transmission peak• Log spectrum analysis• Envelope, optimal Pulse, …

• …

• Inverse Radon Transform• SAFT• SAFT with speed of sound (SOS)• Adapted SAFT• Inverse Born• …

Central problems: low SNR, 20 GB raw data, millions of voxels, changing algos

Current

Averaging

Peak detection

USCT DAQ System

RAM

DAQ PC Reconstruction PC(s)

…

…

……

RAM

RAM

SAFT

Inv. Radon

SOS projection

Workshop on Novel Trends and Approaches in Algorithmand Hardware-Architectures for Image Reconstruction Applications 2009

New Algorithms

Sig. Processing

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Digital Signal and Image Processing

Signal pre-processing

Signal processing

Image reconstruction

• Averaging• Digital Bandpass• Matched filter, e.g. Chirps•…

• Signal detection• Detection of

transmission peak• Log spectrum analysis• Envelope, optimal Pulse, …

• …

• Inverse Radon Transformation• SAFT• SAFT with speed of sound (SOS)• Adapted SAFT• Inverse Born• …

Central problems: low SNR, 20 GB raw data, millions of voxels, changing algos

Vision

Sig.Pre-Processing

Sig.Processing

USCT DAQ System

RAM

Reconstruction PC(s)

…

…

……

RAMS

Image recon.

Image recon.

New Algorithms

Workshop on Novel Trends and Approaches in Algorithmand Hardware-Architectures for Image Reconstruction Applications 2009

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USCT Data Acquisition System

19“ rack: 1 Second Level DAQ Board20 First Level DAQ Board

Sensor excitation control

480 Analogue receive channels 480 x Digital data processingRaw data rate 14 GB/sData storage 20 x 2.4 GB

Data readout 20 MB/s

Workshop on Novel Trends and Approaches in Algorithmand Hardware-Architectures for Image Reconstruction Applications 2009

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Second Level DAQ Board

Measurement control & data readoutProcessor PMC Module

Intel CPU 1GHz, 256 MB SDRAMPCI Master Interface 64/662 x Fast Ethernet (100 Mb)2 x SATA, 4 x USBLinux 2.6Communication to Host (DAQ PC)

FPGAPCI Slave Interface 64/66Master Backplane BusMeasurement Flow ControlCoded excitation for emitters and emitter selection

Workshop on Novel Trends and Approaches in Algorithmand Hardware-Architectures for Image Reconstruction Applications 2009

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First Level DAQ Board

Signal Pre ProcessingAnalog Card Variable Gain AmplifierDigitization @20 MHzFiltering and Decimation to 10 MHzAveraging (up to 128 A-Scan)Data Storage (2.4 GB on Board)

Signal ProcessingTransmission peak detectionOnline calculation Speed of Sound

Workshop on Novel Trends and Approaches in Algorithmand Hardware-Architectures for Image Reconstruction Applications 2009

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USCT Data Acquisition System

Workshop on Novel Trends and Approaches in Algorithmand Hardware-Architectures for Image Reconstruction Applications 2009

8xADC FPGA DAQ FPGA CTRL

RAM

Sys CntrlFPGA

RAM

DAC PMCPC

Record

Send

20 x FL DAQ

1 x SL DAQamplitude shape

Ethernet

24 channels

8xADC8xADC FPGA DAQ

RAM

FPGA DAQ

RAM

Sensor Electronic

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Next GenerationData Acquisition System

Workshop on Novel Trends and Approaches in Algorithmand Hardware-Architectures for Image Reconstruction Applications 2009

ReconfigurableComputing Device:

FPGAGPU

Cell Processor

RAM

Record

N x channels

N x ADC FPGA

Embedded PC withFast Communication

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Conclusion and Discussion

Signal- and image processing for our USCT needs significant acceleration to be clinical relevantParallel processing in data acquisition hardware is possible

Main challenges: Comfortable introduction of new algorithmsReuse of resources for image processing ( reconfiguration)Find optimal hardware configuration for tasks

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AcknowledgementsAlgorithms and ImagingM. Zapf, M. Hardt, and studentsGrid ComputingM. Hardt, R. Stotzka, T. Jejkal, et. al.SensorsG. Göbel, et. al.DAQ and HardwareD. Tcherniakhovski, S. Menshikov, L. Berger, M. Schleicher, M. Ritter et. al.

Workshop on Novel Trends and Approaches in Algorithmand Hardware-Architectures for Image Reconstruction Applications 2009

CooperationsFZK, IMF III: W. Bauer, S. Busch, J. Lorenz, et. al.KIT: ITIV, ISASUniklinikum Jena: J. Reichenbach, P. Balzer, W. Kaiser, et. al.University Brno, Tschechien: R. Jirik, J. Jan, et. al.University Delft, NL: K. van Dongen, et. al.

Reconfigurable FPGAs for USCTUltrasound Computer TomographySpecification of Our System Currents SystemsDigital Signal and Image ProcessingDigital Signal and Image ProcessingUSCT Data Acquisition SystemSecond Level DAQ BoardFirst Level DAQ BoardUSCT Data Acquisition SystemNext Generation�Data Acquisition SystemConclusion and DiscussionAcknowledgements