Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Biological Measurement 1Biological Measurement 1
BIOE 571BIOE 571
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
I. Topics Covered TodayI. Topics Covered Today
• Generation of ultrasoundGeneration of ultrasound• Types of sourcesTypes of sources
• Importance of bandwidth to ultrasonic Importance of bandwidth to ultrasonic imagingimaging
• Importance of field characteristics of Importance of field characteristics of sources to ultrasonic imagingsources to ultrasonic imaging
• Modeling of fieldsModeling of fields
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Single-element TransducerSingle-element Transducer
Wire
Damping Material
Crystal
Acoustic Matching Layer
Insulating Layer
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Importance of BandwidthImportance of Bandwidth
h(t)
v(t)
v(t)*h(t)
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Range Resolution Range Resolution TT11
TT22 A-modeA-mode
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Beam PatternsBeam Patterns
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Imaging with a Flat PistonImaging with a Flat Piston
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Imaging with a Flat PistonImaging with a Flat Piston
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Imaging with a Flat PistonImaging with a Flat Piston
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Imaging with a Flat PistonImaging with a Flat Piston
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Imaging with a Flat PistonImaging with a Flat Piston
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Imaging with a Flat PistonImaging with a Flat Piston
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Imaging with a Flat PistonImaging with a Flat Piston
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
B-Mode ImagingB-Mode Imaging
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Array TransducersArray Transducers
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Linear ArrayLinear Array
1.1. Can steer beam in azimuth plane only (along y)Can steer beam in azimuth plane only (along y)
2.2. Non-symmetric beam (tighter in y than x)Non-symmetric beam (tighter in y than x)
3.3. Can focus to different depthsCan focus to different depths
xx
yy
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Annular ArrayAnnular Array
1.1. Can change focal lengthCan change focal length
2.2. Symmetric beamSymmetric beam
xx
yy
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
1.5D Array1.5D Array
1.1. Can steer beam in azimuth plane (y)Can steer beam in azimuth plane (y)
2.2. Non-symmetric beam (tighter in y than x)Non-symmetric beam (tighter in y than x)
3.3. The transverse plane (x) is used for elevational The transverse plane (x) is used for elevational focusingfocusing
xx
yy
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
2D Array2D Array
1.1. Can steer beam in both directions (x and y)Can steer beam in both directions (x and y)
2.2. Elevational focusingElevational focusing
3.3. Many channels needed to operateMany channels needed to operate
xx
yy
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Array Imaging: Steering, Low F-NumberArray Imaging: Steering, Low F-Number
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Array Imaging: Steering, Low F-NumberArray Imaging: Steering, Low F-Number
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Array Imaging: Steering, Low F-NumberArray Imaging: Steering, Low F-Number
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Array Imaging: Steering, Low F-NumberArray Imaging: Steering, Low F-Number
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Array Imaging: Steering, Low F-NumberArray Imaging: Steering, Low F-Number
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Array Imaging: Steering, Low F-NumberArray Imaging: Steering, Low F-Number
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Array Imaging: Steering, High F-NumberArray Imaging: Steering, High F-Number
Same Trade-offs as with single elements except, Same Trade-offs as with single elements except, no need to translate source (electronic steering) no need to translate source (electronic steering) and no need to use multiple transducers with and no need to use multiple transducers with different f-numbers (electronic focusing)…different f-numbers (electronic focusing)…
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Simple Linear Array: MainlobesSimple Linear Array: Mainlobes
kd = 8.16kd = 8.16
N = 10N = 10
Multiple main lobes Multiple main lobes can occur, which can occur, which causes image causes image degradation in a degradation in a ultrasonic imaging ultrasonic imaging system.system.
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Simple Linear Array: MainlobesSimple Linear Array: Mainlobes
kd = 5.6549kd = 5.6549
N = 10N = 10
Only one mainlobe Only one mainlobe and no grating lobesand no grating lobes
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Simple Linear Array: SteeringSimple Linear Array: Steering
kd = 5.6549kd = 5.6549
N = 10N = 10
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Simple Linear Array: SteeringSimple Linear Array: Steering
kd = 5.6549kd = 5.6549
N = 10N = 10
With same settings With same settings and steering the and steering the beam to 45 degrees, beam to 45 degrees, we can see the we can see the mainlobe at -23 mainlobe at -23 degrees (but still 10 degrees (but still 10 lobes away).lobes away).
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Simple Linear Array: SteeringSimple Linear Array: Steering
kd = 2.8724kd = 2.8724
N = 10N = 10
One mainlobe, but One mainlobe, but fundamental fundamental engineering trade-off engineering trade-off is that the mainlobe is that the mainlobe is wider.is wider.
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Linear ArrayLinear Array
Element has width 2a and height 2bElement has width 2a and height 2b
xx
yy
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Simple Linear Array: Element FactorSimple Linear Array: Element Factor
- H- Hee
-- H- H
HHTOTTOT
kd = 5.6549kd = 5.6549
N = 10N = 10
..
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Simple Linear Array: Element FactorSimple Linear Array: Element Factor
- H- Hee
-- H- H
HHTOTTOT
kd = 8.482kd = 8.482
N = 10N = 10
..
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Simple Linear Array: Element factorSimple Linear Array: Element factor
- H- Hee
-- H- H
HHTOTTOT
kd = 5.6549kd = 5.6549
N = 10N = 10
..
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Simple Linear Array: SteeringSimple Linear Array: Steering
- H- Hee
-- H- H
HHTOTTOT
kd = 5.6549kd = 5.6549
N = 10N = 10
..
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Simple Linear Array: SteeringSimple Linear Array: Steering
- H- Hee
-- H- H
HHTOTTOT
kd = 2.8274kd = 2.8274
N = 10N = 10
..
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Simple Linear Array: ApodizationSimple Linear Array: Apodization
-- H - apodization- H - apodization
HH - no apodization- no apodization
kd = 2.8274kd = 2.8274
N = 10N = 10
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Simple Linear Array: ApodizationSimple Linear Array: Apodization
kd = 5.1408kd = 5.1408
N = 10N = 10
-- H - apodization- H - apodization
HH - no apodization- no apodization
00°° steering steering
Oelze - ECE 571 Lecture 2Oelze - ECE 571 Lecture 2
Simple Linear Array: ApodizationSimple Linear Array: Apodization
kd = 5.1408kd = 5.1408
N = 10N = 10
-- H - apodization- H - apodization
HH - no apodization- no apodization
4545°° steering steering
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