title: Multifrequency synthesis and extraction using square wave projection patterns for quantitative tissue imaging.
abstract: We present a method for spatial frequency domain data acquisition utilizing a multifrequency synthesis and extraction (MSE) method and binary square wave projection patterns. By illuminating a sample with square wave patterns, multiple spatial frequency components are simultaneously attenuated and can be extracted to determine optical property and depth information. Additionally, binary patterns are projected faster than sinusoids typically used in spatial frequency domain imaging (SFDI), allowing for short (millisecond or less) camera exposure times, and data acquisition speeds an order of magnitude or more greater than conventional SFDI. In cases where sensitivity to superficial layers or scattering is important, the fundamental component from higher frequency square wave patterns can be used. When probing deeper layers, the fundamental and harmonic components from lower frequency square wave patterns can be used. We compared optical property and depth penetration results extracted using square waves to those obtained using sinusoidal patterns on an in vivo human forearm and absorbing tube phantom, respectively. Absorption and reduced scattering coefficient values agree with conventional SFDI to within 1% using both high frequency (fundamental) and low frequency (fundamental and harmonic) spatial frequencies. Depth penetration reflectance values also agree to within 1% of conventional SFDI.
authors.affiliation: Beckman Laser Institute, Laser Microbeam and Medical Program, 1002 Health Sciences Road, Irvine, California 92612 United States.
authors.forename: Kyle P
authors.initials: KP
authors.lastname: Nadeau
authors.affiliation: Beckman Laser Institute, Laser Associated Sciences, Photonic Incubator, 1002 Health Sciences Road, Irvine, California 92612 United States.
authors.forename: Tyler B
authors.initials: TB
authors.lastname: Rice
authors.affiliation: Beckman Laser Institute, Laser Microbeam and Medical Program, 1002 Health Sciences Road, Irvine, California 92612 United States.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Durkin
authors.affiliation: Beckman Laser Institute, Laser Microbeam and Medical Program, 1002 Health Sciences Road, Irvine, California 92612 United States.
authors.forename: Bruce J
authors.initials: BJ
authors.lastname: Tromberg
mesh_terms: D003198:Computer Simulation; D005542:Forearm / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008029:Lighting / Q000379:methods*; D008954:Models, Biological; D009391:Nephelometry and Turbidimetry / Q000379:methods*; D019047:Phantoms, Imaging; D010781:Photography / Q000295:instrumentation / Q000379:methods*; D012031:Refractometry / Q000295:instrumentation / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity