Near Infrared Noninvasive Optical Imaging (NIR NOISE) on Objects Hidding in a Scattering Medium
Date
2007-08
Authors
Tennant, Elaine E.
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Abstract
Non-invasive optical imaging by speckle ensemble (NOISE) is a technique for taking an image of an object while it is embedded between two scattering mediums. These mediums can be anything from smoke to frosted glass to biological tissue. The images taken of the object are speckled because of the scattering of the light by the medium surrounding the object. In order to reduce the effect of the scattering we have taken multiple images from different direction using a multi lens array. After running an algorithm that averages all the images together, the scattering has been compensated for and the object becomes obvious.
These methods have applications in medical, military and even law enforcement fields. Human tissue is an appropriate scattering medium and has an added benefit of being partially transparent to light in the near infrared spectrum. This property can be exploited for medical purposes.
We have built a NOISE setup at our University that works in the near infrared and have used it to study binary objects embedded in chicken meat (used to simulate human tissue). Our setup has a smaller surface area than Dr. Rosen’s (eight sq. ft. versus thirty two sq. ft.) It also includes two diaphragms that were not included in Dr. Rosen’s setup. Images were also taken with different scattering mediums with two different wavelengths of light. An image was extracted from a picture of an object embedded in three cm of chicken meat, which is a thicker scattering medium that Dr. Rosen used. The optical properties of the chicken breast were measured using two different methods. Two separate programs were written to deal with the speckle processing, as well as a real-time version. These results as well as the constructed setup will be discussed.
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Keywords
light scattering, optical imaging, non-invasive optical imaging by speckle ensemble, NOISE, optical properties
Citation
Tennant, E. E. (2007). Near infrared noninvasive optical imaging (NIR NOISE) on objects hidding [ie hiding] in a scattering medium (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.