Three-dimensional imaging using absorption
AssigneeMassachusetts Institute of Technology
InventorsDouglas P. Hart, Federico Frigerio, Davide M. Marini
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Abstract
The attenuation and other optical properties of a medium are exploited to measure a thickness of the medium between a sensor and a target surface. Disclosed herein are various mediums, arrangements of hardware, and processing techniques that can be used to capture these thickness measurements and obtain three-dimensional images of the target surface in a variety of imaging contexts. This includes general techniques for imaging interior/concave surfaces as well as exterior/convex surfaces, as well as specific adaptations of these techniques to imaging ear canals, human dentition, and so forth.
Claims17
A method for obtaining three-dimensional data comprising:
- distributing a medium between a target surface and a sensor, the target surface having a predetermined color over a region of interest, and the medium characterized by a first predetermined attenuation coefficient at a first wavelength and a second predetermined attenuation coefficient different from the first attenuation coefficient at a second wavelength;
- illuminating a location in the region of interest;
- measuring an intensity of the first wavelength and an intensity of the second wavelength in a direction of the location with the sensor;
- and
- determining a thickness of the medium in the direction of the location based upon a ratio of the intensity of the first wavelength and the intensity of the second wavelength;
- determining a plurality of additional thicknesses within the region of interest;
- and
- reconstructing a three-dimensional image of the region of interest based upon the thickness and the plurality of additional thicknesses.
A computer program product embodied in a non-transitory computer-readable medium that when executing on one or more computing devices performs the steps of:
- characterizing a color over a region of interest on a target surface to provide a predetermined color;
- characterizing a first predetermined attenuation coefficient at a first wavelength and a second predetermined attenuation coefficient at a second wavelength of a medium distributed between the target surface and a sensor;
- receiving a measurement from the sensor in a direction of a location in the region of interest, the measurement including an intensity at the first wavelength and an intensity at the second wavelength;
- calculating a thickness of the medium in the direction of the location based upon a ratio of the intensity of the first wavelength and the intensity of the second wavelength;
- and displaying the thickness in a user interface of a computer.
A device comprising:
- a target surface having a predetermined color over a region of interest;
- a sensor capable of measuring an intensity of electromagnetic radiation from a location in the region of interest including an intensity at a first wavelength and an intensity at a second wavelength;
- a medium distributed between the target surface and the sensor, the medium characterized by a first predetermined attenuation coefficient at the first wavelength and a second predetermined attenuation coefficient different from the first attenuation coefficient at the second wavelength;
- a light source capable of illuminating the region of interest at the first wavelength and the second wavelength;
- and
- a processor programmed to receive the intensity at the first wavelength and the intensity at the second wavelength from the sensor and to calculate a thickness of the medium in a direction of the location based upon a ratio of the intensity of the first wavelength and the intensity of the second wavelength, the processor further configured to similarly determine a plurality of additional thicknesses over the region of interest, and to reconstruct a three-dimensional image of the region of interest based upon the thickness and the plurality of additional thicknesses.
Dependencies are inferred from the claim text.