@article{prahl10a,
  author = {Scott Prahl and Amanda Dayton},
  title = {Distance Measurement Device and Method of Use Thereof},
  journal = {United States Patent Application},
  year = {February 2010},
  abstract = {Systems and methods of utilizing a frequency modulation technique to determine an unknown distance between at least one source and at least one detector in an light scattering medium without knowing the optical properties of the medium are described. Modulated light is emitted from a light source to an optical scattering and absorbing medium and at least a portion of the modulated light is detected with a detector. A calibration factor is determined and then an unknown distance between at least one source and at least one detector can be determined, thereby providing a distance measurement.},
}