Three-dimensional imaging using a single camera
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.
1. A device comprising:
a camera including a lens and one or more sensors capable of capturing a two-dimensional color image of a field of view including an intensity at a first wavelength and an intensity at a second wavelength for each of a plurality of pixel locations in a two-dimensional array, each one of the plurality of pixel locations corresponding to a direction from the lens into the field of view; and
a processor programmed to calculate a thickness through a medium to a luminescent layer, the medium being a non-fluorescent medium, in the direction corresponding to each one of the plurality of pixel locations as a function of a ratio of the intensity of the first wavelength to the intensity of the second wavelength at that one of the plurality of pixel locations, thereby providing a plurality of thickness measurements, the processor further programmed to calculate a three-dimensional image of an object within the field of view based upon the plurality of thickness measurements.
2. The device of claim 1 wherein the one or more sensors include CMOS sensors.
3. The device of claim 1 wherein the one or more sensors include charge-coupled devices.
4. The device of claim 1 further comprising a plurality of filters for selectively capturing an intensity of different wavelengths at different ones of the plurality of pixel locations.
5. The device of claim 4 wherein the one or more sensors include a solid state imaging device, the plurality of filters further comprising a filter mask disposed on the solid state imaging device.
6. The device of claim 4 wherein the plurality of filters include a plurality of filters selectively disposed between the lens and the one or more sensors, thereby permitting a series of time-separated, wavelength-separated images at each of the first wavelength and the second wavelength.
7. The device of claim 1 wherein the intensity of the first wavelength and the intensity of the second wavelength are calculated at each one of the plurality of pixel locations based upon three discrete wavelength measurements.
8. The device of claim 7 wherein the three discrete wavelength measurements include a measurement at each of a red wavelength, a blue wavelength, and a green wavelength.
9. The device of claim 7 wherein the three discrete wavelength measurements include a measurement at a cyan wavelength, a magenta wavelength and a yellow wavelength.
10. The device of claim 1 further comprising a bath to contain the medium, wherein the medium has at least one known surface when disposed within the bath, the at least one known surface used to recover the three-dimensional image of the object from the plurality of thickness measurements.
11. The device of claim 1 where the thickness is calculated from a surface of the lens to an object through the medium.
12. The device of claim 1 further comprising a light source capable of illuminating the object.
13. The device of claim 12 wherein the light source is a broadband light source.
14. The device of claim 12 wherein the light source includes an excitation light source for exciting a fluorescent substance disposed on an exterior surface of the object.
15. The device of claim 12 further comprising a filter that shapes light emitted from the light source.