Intraoral imaging system and method based on conoscopic holography

1. A method for imaging a scene characterized by a surface having a three-dimensional shape, the method comprising:

a. illuminating the scene so as project onto the surface of the scene a plurality of light stripes from a source of illumination, the plurality of light stripes defining an instantaneous elementary object, the instantaneous elementary object varying with time to produce a succession of elementary objects;

b. imaging the succession of elementary objects through an optical coding module to form a sequence of conoscopic holograms, each conoscopic hologram respectively corresponding to an elementary object from the succession of the elementary objects; and

c. computing the three-dimensional shape of the surface based upon the sequence of conoscopic holograms.

2. A method according to claim 1 , wherein the scene is interior to a mouth of a person.

3. A method according to claim 1 , wherein the surface includes translucent material.

4. A method according to claim 1 , wherein illuminating the scene includes varying a relative position between the source of illumination and the scene.

5. A method according to claim 4 , wherein varying the relative position includes translating a source of illumination relative to the scene.

6. A method according to claim 1 , wherein illuminating the scene further comprises delivering light from a source of illumination through a plurality of optical waveguides.

7. A method according to claim 6 , wherein the optical waveguides include optical fibers disposed in a fiber-bundle assembly.

8. A method according to claim 1 , wherein illuminating the scene includes illuminating the scene through relay optics.

9. A method according to claim 8 , wherein illuminating the scene includes illuminating the scene through a periscope.

10. A method according to claim 8 , wherein illuminating the scene includes illuminating the scene through a telescope.

11. A method according to claim 1 , wherein imaging the successive elementary objects through the optical coding module includes imaging the successive elementary objects through a conoscope.

12. A method according to claim 1 , wherein evaluating the three-dimensional shape of the surface of the scene further comprises independently analyzing N elementary conoscopic figures, N being a number of lines in the plurality of lines of illumination, each elementary conoscopic figure representing imaging of a single emitting point on a respective line from the plurality of lines of illumination.

13. A method according to claim 1 , wherein evaluating the three-dimensional shape of the surface of the scene from the sequence of conoscopic holograms includes evaluating three-dimensional shape of the surface of the scene from the sequence of exponential optical conoscopic holograms.

14. A method according to claim 13 , further comprising a weighted reconstruction of exponential holograms at a median plane.

15. A method according to claim 1 , wherein imaging the successive elementary objects through the optical coding module to form the sequence of optical conoscopic holograms of the succession of elementary objects includes imaging a successive elementary object without displacement thereof and with respective different polarization arrangements to form an elementary set of conoscopic holograms.

16. A method according to claim 15 , further comprising processing, in an external processing unit, digital representations of optical conoscopic holograms from the elementary set to remove a bias and a conjugate image.

17. A conoscopic holographic system comprising:

an optical source;

an array generator for providing a plurality of light stripes;

a detector array for registering a plurality of conographic holograms based on the light stripes; and

a processor for measuring a distance from a specified point on a surface of a body to a fiducial reference position based on the plurality of conographic holograms and for generating a signal representing the distance.

18. A conoscopic holographic system according to claim 17 , further comprising a periscope projecting the plurality of stripes of light onto a scene characterized by a surface.

19. A conoscopic holographic system according to claim 17 , further comprising imaging optics configured to provide independent registration, in an image plane, of N elementary conoscopic figures.

20. A conoscopic holographic system according to claim 19 , wherein each elementary conoscopic figure represents imaging of a single emitting point on a respective substantially linear distribution of light from the plurality of substantially linear distributions of light, single emitting points being optical conjugates of photosensitive elements in a detector disposed in an image plane, the optical conjugates defined by the imaging optics.

21. A conoscopic holographic system according to claim 19 , wherein the imaging optics are anamorphic.

22. A method for determining a distance to an illuminated surface with a linear conoscope, the linear conoscope characterized by an image plane and an optical axis, the illuminated surface being illuminated with N substantially linear distributions of light, the method comprising:

in a first computer process, representing an image irradiance measured in the image plane with a detector as a weighted combination of N functions, each function representing an elementary signal contributed to the image irradiance by a corresponding single emitting point from a respective linear distribution of light;

in a second computer process, for each of the single emitting points, correlating a weighted test function and the weighted combination to generate a correlation function, the weighted test function being weighted with a factor representing a lateral displacement of the respective single emitting point from the optical axis; and

in a third computer process, for each of the single emitting points, determining a longitudinal separation between the image plane and a respective emitting point from a maximum of the correlation function.