Hadamard Transform Imaging Paul Holcomb Tasha Nalywajko Melissa

Hadamard Transform Imaging Paul Holcomb Tasha Nalywajko Melissa Walden

Problem Definition • Current 3 D spectral imaging systems are relatively slow and possess low resolution • Hadamard multiplexing greatly enhances signal to noise ratio, thus enhancing resolution • Use of a digital micro-mirror device makes implementation of the Hadamard transform very fast

Hypothesis Implementation of the Hadamard transform in a spectral imaging system by using a digital micromirror device will decrease the amount of time necessary to acquire an image and increase the spatial and spectral resolution of the image. Faster, more accurate spectral imaging will allow for better differentiation of tissue during brain tumor resectioning and increase survival rates.

3 D Spectral Imaging Techniques Scanning Line Scanning http: //www. lightforminc. com/Technology/ANIMATION/animation. html Wavelength Scanning http: //www. cri-inc. com/instruments/data/pdf/American%20 Laboratory%202000. pdf

3 D Spectral Imaging Techniques Multiplexing Fourier Transform http: //scienceworld. wolfram. com/physics/Fourier. Transform. Spectrometer. html Hadamard Transform Wuttig and Riesenburg, “Sensitive Hadamard Transform Imaging Spectrometer with a simple MEMS”

Benefits of Hadamard Multiplexing • Decreased image acquisition time vs. scanning techniques • Increased signal to noise ratio § √n for Hadamard matrix § (√n)/2 for S matrix Wuttig and Riesenburg, “Sensitive Hadamard Transform Imaging Spectrometer”

What do we want? • Focus a 25 mm square into a 10 mm square • Bounce the square with specific pixels at specific angles (apply Hadamard matrix) • Compress the light in one direction line • Separate the line by wavelength Goal: Capture the spectrum of the line

Stage 1 – Compress image

Digital Micro-Mirror Device http: //www. ostl. ece. uvic. ca/IMAGES/emiod. png

Stage 2 – Compress into a line

Drawn to scale…

Stage 1

Construction

Lens System with Testing Lens

Testing of Stage 1

Testing with Square Source

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

Future Directions • Finish construction and testing by mid. January • Implement 2 leg system (Full Hadamard) • Miniaturization Thanks from Group 10!