Abstract: The disclosure features systems and methods for detecting a user's facial movement and expression, that include a plurality of radiation sources, a plurality of radiation detectors, where each radiation detector is paired with a different one of the radiation sources and configured to detect radiation emitted by its paired radiation source, and a controller connected to the radiation detectors and configured to receive signals corresponding to measurements of emitted radiation from each of the radiation detectors, determine, for each radiation source-detector pair, information about whether a radiation path between the source and detector is blocked by a portion of the user's face, and determine a facial movement or expression of the user based on the information.

Abstract: The disclosure features systems and methods for detecting a user's facial movement and expression, that include a plurality of radiation sources, a plurality of radiation detectors, where each radiation detector is paired with a different one of the radiation sources and configured to detect radiation emitted by its paired radiation source, and a controller connected to the radiation detectors and configured to receive signals corresponding to measurements of emitted radiation from each of the radiation detectors, determine, for each radiation source-detector pair, information about whether a radiation path between the source and detector is blocked by a portion of the user's face, and determine a facial movement or expression of the user based on the information.

Abstract: A method for assessing mechanical properties of a selected tissue includes defining an expansion chamber adjacent to the selected tissue and passing pressurized air into the expansion chamber. The method also includes providing an opening through which the pressurized air can escape the expansion chamber, the opening being disposed such that, while escaping from the expansion chamber, air passes by the selected tissue, thereby causing the selected tissue to vibrate.

Abstract: A method for assessing mechanical properties of a selected tissue includes defining an expansion chamber adjacent to the selected tissue and passing pressurized air into the expansion chamber. The method also includes providing an opening through which the pressurized air can escape the expansion chamber, the opening being disposed such that, while escaping from the expansion chamber, air passes by the selected tissue, thereby causing the selected tissue to vibrate.

Abstract: An apparatus for causing air flow to vibrate a selected tissue includes a tube and a deflector. The tube defines a passage for guiding air flow from an inlet to an outlet thereof. The deflector is disposed to receive the air flow from the outlet of the tube. The configuration of the deflector is such as to channel air flow from the outlet past the selected tissue. This causes vibration of the selected tissue.