Speckle Noise Reduction in Optical Coherence Tomography By: Marisse Foronda Rishi Matani Hardik...
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Transcript of Speckle Noise Reduction in Optical Coherence Tomography By: Marisse Foronda Rishi Matani Hardik...
Speckle Noise Reduction in Optical Coherence
Tomography
By:Marisse Foronda
Rishi MataniHardik MehtaArthur Ortega
Cow Retina
Speckle
wave fronts
sample volume
multipleforwardscatter
multipleback
scatter
tissuemodulatedwave fronts
BackgroundMinimally-Invasive to Non-Invasive imaging
systemClinically used High Resolution alternate to ultrasound imagingOne significant problem is speckle formation
Deformable Mirror
Intensity LossVarying Patterns can cause loss of intensity of
image and change in percent reflectivity
First, we must characterize default intensity loss by placing a flat mirror at the sample arm and having no deformations on the deformable mirror
Then, we deform mirror and characterize loss:3 dB loss 50% loss6 dB loss 75% loss9 dB loss 87.5% loss
Image Assembly100%
80%
Amplitude
% light reflected
Pattern 1
Pattern 2
Amplitude
% light reflected
100%
80%
Contrast Ratio
CorrelationIf two images have speckle patterns that are the
same, averaging them gives us no reduction in that speckle
We have to characterize how similar two images are using the formula:
Gantt Chart
Number Task Start End Duration2010
January February March April May
1 Familiarize with Project 1/4/2010 1/22/2010 19
2 Construction of Device 1/26/2010 3/5/2010 39
3 Mirror Testing 3/6/2010 3/12/2010 7
4 Agar Testing 4/1/2010 4/29/2010 29
5 Biological Tissue Testing 5/1/2010 5/29/2010 29
Weekly ProgressWeek 1 Read Papers on our Design
Familiarized ourselves with the lab
Week 2 Took Measurements of Components
Drew out a system diagram
Week 3 Ordered all necessary components
Began assembling the system
Week 4 Fine tune/align the system
Defective Galvo cables diagnosed
Week 5 Waiting for new Galvo cables
Week 6 Finish Assembly of Device
Week 7 Finish Assembly of Device
Week 8 Galvo Wires arrived
Week 9 Fine Tuning/Alignment
Prototype System
Reverse Alignment
deformable mirrorfiber and collimator
2D-galvo scanners
fiber and collimator
3.0 mW
0 µW
2.5 mW
526 W
480 W
deformable mirrorfiber and collimator
2D-galvo scanners
fiber and collimator
3.0 mW
1 µW
2.5 mW
526 W
480 W
deformable mirrorfiber and collimator
2D-galvo scanners
fiber and collimator
3.0 mW
5 µW
2.5 mW
526 W
480 W
deformable mirrorfiber and collimator
2D-galvo scanners
fiber and collimator
3.0 mW
10 µW
2.5 mW
526 W
480 W
deformable mirrorfiber and collimator
2D-galvo scanners
fiber and collimator
3.0 mW
20 µW
2.5 mW
526 W
480 W
deformable mirrorfiber and collimator
2D-galvo scanners
fiber and collimator
3.0 mW
35 µW
2.5 mW
526 W
480 W
deformable mirrorfiber and collimator
2D-galvo scanners
fiber and collimator
3.0 mW
50 µW
2.5 mW
526 W
480 W
deformable mirrorfiber and collimator
2D-galvo scanners
fiber and collimator
3.0 mW
80 µW
2.5 mW
526 W
480 W
deformable mirrorfiber and collimator
2D-galvo scanners
fiber and collimator
3.0 mW
125 µW
2.5 mW
526 W
480 W
C2
M
C1
input
output
G
Forward Alignment
deformable mirrorfiber and collimator
2D-galvo scanners
fiber and collimator
3.0 mW
10 µW
2.2 mW
2.1 mW
486 W
deformable mirrorfiber and collimator
2D-galvo scanners
fiber and collimator
3.0 mW
30 µW
2.2 mW
2.1 mW
486 W
deformable mirrorfiber and collimator
2D-galvo scanners
fiber and collimator
3.0 mW
119 µW
2.2 mW
2.1 mW
486 W
C1
MG
C2
Input
Output
Power ResultsForward Alignment
Path Power % Loss
Input-C1 3.0 mW
C1-M 2.2 mW 26.7%
M-G 2.1 mW 4.5%
G-C2 486 µW 76.9%
C2-Output
119 µW 75.5%
Reverse Alignment
Path Power % Loss
Input-C1 3.0 mW
C1-M 2.5 mW 16.7%
M-G 526 µW 78.9%
G-C2 480 µW 8.7%
C2-Output
125 µW 74%
-AR (anti-reflection) coating on Galvo mirrors (1310 nm) -Fibers (1310 nm)-Power Source (800 nm)
ConclusionQuantitative Benchmark: Reduce contrast ratio
by 25% - 50% with a 6 dB mean intensity loss
Future Applications: Any Imaging system using a coherent light source can easily integrate the deformable mirror component.
Integration of the mirror will be efficient and cost effective.
Questions