comprehensive ultrasound research platform emma muir sam muir jacob sandlund david smith advisor:...

Comprehensive Ultrasound Comprehensive Ultrasound Research PlatformResearch Platform

Emma MuirSam MuirJacob SandlundDavid Smith

Advisor: Dr. SánchezCo-advisor: Dr. Irwin

22

OutlineOutlineIntroductionSystem

◦ Block Diagram / Functional Description◦ Requirements

Progress

33



Progress

3

44

Ultrasound IntroductionUltrasound IntroductionPiezoelectric Transducer

◦Pulse ExcitationChanges in density reflect waves

55

ObjectiveObjectiveCreate an Ultrasound Research Platform

◦ Image Creation◦Multi-pin

Beamforming

◦Sigma Delta Architecture 1-bit ADC

◦Arbitrary Waveforms Coded excitation signals Configurable delays

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66

MotivationMotivationImprove Ultrasound TechniquesMedical Applications

◦Detecting tumors and abnormalitiesFuture Research

6

77

SignificanceSignificanceTest codes (arbitrary) for

better imagingMulti-pin to allow

BeamformingArchitecture reduces cost

and size◦RASMUS

Two 19 inch racks

◦Sigma Delta vs. 12+ bit DAC

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88



Progress

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99

Block DiagramBlock Diagram

1010

PC Data ProcessingPC Data Processing

Pulse Compression

Delay Sum Beamforming

Time-Gain Compensation

Envelope Detection

GUI

Receive Data

Log Compression

1111



Progress

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System RequirementsSystem RequirementsUp to 8 transducer channelsExcitations <= 3 μs

◦Time-bandwidth product of 40High frequency design

◦Signal to noise ratio (SNR) > 50 dB

13

Sigma Delta ModulationSigma Delta Modulation

< 10% MSE500 M samples/secondTrade off

◦Accuracy vs. Stability◦OSR = 16 (must be a power of 2)◦Order = 2nd

1414

FPGA RequirementsStore data on DDR2

◦62.5 MHz ◦8 waveforms◦1536 bits per waveform

Output Data◦8 Individualized Pins◦Delays of up to 5 s◦500 MHz

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FPGA to PC CommunicationUART

◦115200 baudSend waveform dataAssign waveform to pinsAssign delay to pinsStart transmission

1616

Data Processing◦Less than 2 minutes

Display an image ◦Depths between 0.25 cm and 30 cm.◦Adjust contrast

Graphical User Interface (GUI)

1717



Progress

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ProgressID Task Name % Complete

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40%Design and Test Analog Components

90%Finalize FPGA Signal Transmission

100%Create / Test UART connection logic

100%Design / Test Delay Sum Beamforming

15%Design Analog Front End Settings

90%Design and Test all MATLAB code

100%Design GUI for Depth/Contrast

0%Test Amplifier with Sigma Delta Signal

0%Rewrite MATLAB code in C

70%Test UART / FPGA Outputs

0%Test Analog Front End Capturing

0%Test Complete Analog System/Probe

0%Combine and Test all C Code

0%Test Complete System

0%2011 Student Scholarship Exposition

0%Write Presentation and Final Report

0%Final Presentation

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2020

Amplifier ProgressDifferent designs examined

◦H-Bridge

◦2 MOSFETs Push-pull RF MOSFET

◦1 MOSFET N-channel RF MOSFET Final Design

Amplifier Progress

Discuss problems/solutions

Amplifier Progress

T/R Switch ProgressT/R Switch Progress

27

V 15

V 25

0 0

0

U 1TX8 1 0

B11

B22

B33

GN

D4

I N 15

I N 26

I N 37

I N 48

I N 59

I N 61 0

I N 71 1

I N 81 2

O U T11 3

O U T21 4

O U T31 5

O U T41 6

O U T51 7

O U T61 8

O U T71 9

O U T82 0

VB21

VD22

VN23

VP24

V 9

F R E Q = 2 M e gV A M P L = XV O F F = 0

0 0

V 4-5

0 0

V 55

0

V 60

V B

V 75

0

V 85

O U T1O U T2O U T3O U T4O U T5O U T6O U T7O U T8

O U T1R 2

4 0 0

C 1

1 5 p V B O U T2R 3

4 0 0

C 2

1 5 p V BR 4

4 0 0

O U T3

C 3

1 5 p V B O U T4R 5

4 0 0

C 4

1 5 p V B

O U T5R 6

4 0 0

C 5

1 5 p O U T6R 7

4 0 0

C 6

1 5 p O U T7R 8

4 0 0

C 7

1 5 p O U T8V BR 9

4 0 0

C 8

1 5 p V BV BV B V BV B

T/R Switch ProgressT/R Switch Progress

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Time

0s 0.2us 0.4us 0.6us 0.8us 1.0us 1.2us 1.4us 1.6us 1.8us 2.0usV(OUT1) MAX(V(OUT1))- MIN(V(OUT1))

-1.0V

-0.5V

-0.0V

0.5V

1.0V

1.5V

2.0V

1.92V

PCB ProgressFootprints

◦TX810 Transmit/Receive

Switch

◦RF MOSFET Set INTO board

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FPGA ProgressArbitrary transmissionOutput verified

◦500 MHzMulti-pin

◦Currently 4◦Adjustable

Arbitrary length◦Must be 256 bit pieces

Adjustable delays of < 33 ms33

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FPGA Flowchart Progress

Receive Waveform

Data(UART)

Store to Memory

Is Signal to Transmit

Request Waveform Data

(X8)

Transmit to Pin(X8)

Is Data Received?

No

Delay (X8)Delay (X8)

Yes

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FPGA RemainingFix storing waveform data from UART

◦ Inconsistent resultsIncrease delays precision

◦After data retrievedMake output more exactChange to 8 pins

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UART ProgressUART

◦115200 baud worksPC to FPGA Communication

◦Start transmission signal◦Set waveforms to pins◦Set delays for pins◦Waveform data

Inconsistent

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Waveform GUI FeaturesWaveform GUI FeaturesMultiple selectionAutomatic pin settings removalSave/Load settingsCheck files exist when loading settingsLet “None” represent an array of 0’s

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FPGA Results

-2 -1 0 1 2 3 4

x 10-6

-5

0

5

10

-2 -1 0 1 2 3 4

x 10-6

-5

0

5

10

Time (s)

Time (s)

Delayed

Cross-talk Cross-talk

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FPGA Results

-5 0 5

x 104

-0.2

0

0.2

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0.6

0.8

1

1.2

Normalized Correlation

Sample number

Max Corr. = 0.97

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FPGA Results

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FPGA Results

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FPGA Results

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Analog Front End Results

Source: Analog Devices UG-016 http://www.analog.com/static/imported-files/user_guides/UG-016.pdf

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AlternativesAnalog Front End

◦12 bit resolution◦80 MSPS

Lecroy High Speed Oscilloscope◦725Zi ◦8 bit Resolution◦20 GSPS◦4 Channels

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BeamformingBeamforming

Delay based on distance from point to sensor and distance from sensor to focal point

Note: No delay at the Focal Point

Sensors

Focal Point

Point

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Without Beamforming With Beamforming

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AttenuationAverage frequency attenuation in tissue

◦ 0.5 dB/cm/MHz ◦ 5e-5 dB/m/Hz

Doubled for ultrasound imagingFrequency = 8MHzMaximum depth = 30cmMaximum attenuation = 240dBImage dB range = 0dB to -50dB

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Time Gain CompensationBased on depth of point in imageAtt = 1dB/cm/MHzTGC = Att*Depth*8MHzAdd to compensateNote that this increases white noise for

larger depths

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Sigma Delta RepresentationSigma Delta Representation

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0 1 2 3 4 5 6 7-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 1 2 3 4 5 6-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Without Pre-Enhanced MagnitudeWithout Pre-Enhanced Magnitude

0 0.2 0.4 0.6 0.8 1 1.2

x 10-5

-1

-0.5

0

0.5

1

0 0.2 0.4 0.6 0.8 1 1.2

x 10-5

-1

-0.5

0

0.5

1

Correlation = 0.9763

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Pre-Enhanced MagnitudePre-Enhanced Magnitude

0 0.5 1 1.5 2 2.5 3

x 10-6

-2

-1

0

1

2

0 0.5 1 1.5 2 2.5 3

x 10-6

-1

-0.5

0

0.5

1

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With Pre-Enhanced MagnitudeWith Pre-Enhanced Magnitude

0 0.2 0.4 0.6 0.8 1 1.2

x 10-5

-1

-0.5

0

0.5

1

0 0.2 0.4 0.6 0.8 1 1.2

x 10-5

-1

-0.5

0

0.5

1

Correlation = 0.9916

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Sigma Delta FeaturesSigma Delta FeaturesEasy to modify

◦Frequency◦Period◦Waveform equation◦Number of samples

Pre-Enhanced MagnitudeChecks/displays correlationWrites output to a file as 0’s and 1’s

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Sigma Delta AdditionsSigma Delta AdditionsGUI interface for entering

◦Frequency◦Period◦Waveform equation

Select location to save fileInterface with Waveform GUI

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REC ResultsMATLAB simulation150% of original bandwidthLinear chirp frequencies

◦1.14 times the bandwidth◦Reduce side-lobes during pulse compression

Apply to finished system

6363

h1(n) * c1(n) = h2(n) * c2(n)

6565

Pulse Compression Results MATLAB simulationWiener filterSNR of 60 dBInput is REC pre-enhanced chirpVaried Smoothing Factor (SF)

◦Operating Point

6767

Field II Simulations

REC Excitation and Pulse Compression

SF = 0.1

Impulse Excitation 67

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MATLAB GUI FeaturesMATLAB GUI FeaturesDepth from 2mm to 231mmMax dB range from 10dB to 60dBUpdate chart settings automaticallyUpdate data in 54s

6969

MATLAB GUI

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MATLAB GUI

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MATLAB GUI AdditionsMATLAB GUI AdditionsDepth from 2mm to 300mmRestrict max dB to 40dB to 60dBAllow user to type value or scrollMinimize update timeConvert to C

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Additional InformationAdditional InformationVisit

http://cegt201.bradley.edu/projects/proj2011/ultra/index.html

76

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Acknowledgments Acknowledgments The authors would like to thank Analog Devices

and Texas instruments for their donation of parts.

This work is partially supported by a grant from Bradley University (13 26 154 REC)

Dr. IrwinDr. LuMr. MattusMr. SchmittAndy Fouts

7878

ReferencesReferences[1] J. A. Zagzebski, Essentials of Ultrasound Physics, St. Louis, MO: Mosby, 1996.

[2] R. Schreier and G. C. Temes. Understanding Delta-Sigma Data Converters, JohnWiley & Sons, Inc., 2005.

[3] R. Schreier, The Delta-Sigma Toolbox Version 7.3. Analog Devices, Inc, 2009.

[4] T. Misaridis and J. A. Jensen. “Use of Modulated Excitation Signals inMedical Ultrasound,” IEEE Trans. Ultrason., Ferroelectr. Freq. Contr., vol. 52, no. 2,pp. 177-191, Feb. 2005.

[5] M. Oelze. “Bandwidth and Resolution EnhancementThrough Pulse Compression,” IEEE Trans. Ultrason., Ferroelectr. Freq. Contr., vol. 54,no. 4, pp. 768-781, Apr. 2007.

[6] Mitzner, Kraig. Complete PCB Design Using OrCad Capture and PCB Editor,Newnes, 2009.

7979

References Cont.References Cont.[7] Montrose, Mark I. Printed Circuit Board Design Techniques For EMC Compliance:A Handbook for Designers, Wiley-IEEE Press, 2000.

[8] J.A. Jensen. Field: A Program for Simulating Ultrasound Systems, Paper presentedat the 10th Nordic-Baltic Conference on Biomedical Imaging Published in Medical &Biological Engineering & Computing, pp. 351-353, Volume 34, Supplement 1, Part 1,1996.

[9] Kai E. Thomenius. Evolution of Ultrasound Beamformers, IEEE Trans. Ultrason., Ferroelectr. Freq. Contr., pp. 1615-1622, 1996.

[10] J.A. Jensen and N. B. Svendsen. Calculation of pressure fields from arbitrarilyshaped, apodized, and excited ultrasound transducers, IEEE Trans. Ultrason.,Ferroelec., Freq. Contr., 39, pp. 262-267, 1992.

[11] Kjærgaard, Nina. "RASMUS." Center for Fast Ultrasound Imaging. Technical University of Denmark, 28 Sept. 2010. Web. 25 Feb. 2011. <http://www.dtu.dk/centre/cfu/English/research/facilities/RASMUS.aspx>.

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Questions?Questions?

Without TGC With TGC

81

Using Delta as the Excitation Signal

Using REC (chirp)

82

comprehensive ultrasound research platform emma muir sam muir jacob sandlund david smith advisor:...

Documents

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fpga flowchart progress

fpga requirementsstore

waveform datauartstore

pinx8is data

data processingless

fpga remainingfix

pinsset delays