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Hadamard Transform Imaging. Paul Holcomb Tasha Nalywajko Melissa Walden. Problem Definition. Current 3D imaging systems for brain surgery are too slow and possess too low of a resolution to be effective in an operating room setting. Why is this important?. - PowerPoint PPT Presentation
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Hadamard Transform Imaging
Paul Holcomb
Tasha Nalywajko
Melissa Walden
Problem Definition
• Current 3D imaging systems for brain surgery are too slow and possess too low of a resolution to be effective in an operating room setting
Why is this important?
• 71% mortality rate for diagnosed brain tumors
• Correlation between complete resectioning of tumors and improved prognosis
• Complete resectioning requires knowing the location of the tumor, especially tumor margins
• Imaging in a clinical setting should be fast• Operating room billed by the quarter- or
half hour
Cost/Benefit Analysis
• Treatment costs:– OR cost: $10K - $15K
per surgery (depending on length)
– ICU: $1963/24 hrs– Floor: $779/24 hrs– Chemotherapy– Radiation therapy
Cost Reduction:
• Shorter surgeries• Less time in hospital (ICU or
floor)• Less post-surgical treatment
required
Design Criteria
• Must produce an image in real time
• Must accurately reproduce area of interest in the brain
• Must distinguish healthy versus tumor tissue
• Must be small enough to be usable in an operating room setting
• Must interface with operating microscope
Design Objective
Construct imaging system using digital micro-mirror device and Hadamard transform for use with operating microscope in a clinical setting
System Design
Hadamard Transform
• Decreased imaging time
• Increased SNR Hadamard Matrix Definition
Inverse Hadamard Transform
Digital Micro-mirror Device
• Allows use of Hadamard Transform
Fourier vs. Hadamard Imaging
Wuttig and Riesenburg, “Sensitive Hadamard Transform Imaging Spectrometer”
SNR Increase with Hadamard: √n
SNR Increase with S-Matrix: (√n)/2
System Diagram
Collect and collimate
reflected light
Illuminate sample with white light
System Diagram
Decrease image size to fit within 512 x 512 matrix
Magnification:~0.4
System Diagram
Apply Hadamard matrix using
DMD
1
1-1
-1
1
1
-1
-1
Compress image to 160um line
Disperse light spectrally using
spectrograph and collect image
using CCD camera
Apply inverse Hadamard
transform using computer
X
YSpectrum
System Diagram
System Output
Design Timeline
February: Align and test Stage 1; align DMD; align and test
Stage 2
March: Insert, align, and test spectrograph; test system
using reflectance standard to determine SNR; test
system using normal and tumor tissue samples
April: Continue testing and analysis; compile and present
findings at Senior Design Day