3d imaging, ranging, and/or tracking using active illumination and point spread function engineering

Abstract

Imaging systems and imaging methods are disclosed to estimate a three-dimensional position of an object at a scene and/or generate a three-dimensional image of the scene. The imaging system may include, for example, one or many light sources; an optical system configured to direct light from the one or more light sources into a pattern onto the scene; a mask; a detector array disposed to receive light from the scene through the mask; and at least one processor communicatively coupled with the detector and configured to estimate a depth of a particle within the scene.

That which is claimed: 
     
         1 . A method comprising:
 illuminating a scene with first light having a pattern, the pattern changing with depth;   directing second light from the scene through an optical system that includes a mask, wherein the optical system generates a point spread function that varies based on depth within the scene, wherein the second light comprises light provided by the scene responsive to illumination by the first light;   producing an image of the scene from the second light that passes through the mask using a light detector; and   estimating a depth of one or more objects within the scene from the image of the scene.   
     
     
         2 . The method according to  claim 1 , wherein the pattern includes a pattern selected from the list consisting of a spot array pattern, a striped pattern, a sinusoidal pattern, a pattern of a sparse set of spots, dynamically changing spot pattern, a scanning spot pattern, a pattern of spots that move independently, and a speckle pattern. 
     
     
         3 . The method according to  claim 1 , wherein the depth of the one or more objects is estimated based on the representation of the point spread function in the image of the scene. 
     
     
         4 . The method according to  claim 1 , wherein the point spread function comprises a double helix point spread function. 
     
     
         5 . The method according to  claim 1 , wherein the mask includes an optical element selected from the list consisting of an optical element with an extended depth of field, a cubic phase mask, a double helix point spread function mask, diffractive optical element, a grating, a Dammann grating, a diffuser, a phase mask, a hologram, an amplitude mask, a spatial light modulator, and a prism array. 
     
     
         6 . The method according to  claim 1 , wherein the second light is the result of one or more of the following: scattering, transmission, absorption, fluorescence, two or multi-photon fluorescence, high harmonic generation, refraction, and/or diffraction at or from the objects of the scene. 
     
     
         7 . A method comprising:
 illuminating a scene with a first light that has a first light pattern;   generating a first image of the scene from second light from the scene that passes through a first mask using a light detector, wherein the second light comprises light provided by the scene responsive to illumination by the first light;   illuminating the scene with a third light that has a second light pattern that is different from the first light pattern;   generating a second image of the scene from fourth light from the scene that passes through a second mask using the light detector, wherein the fourth light comprises light provided by the scene responsive to illumination by the third light; and   estimating a depth of one or more objects within the scene from the first image of the scene and/or the second image of the scene.   
     
     
         8 . The method according to  claim 7 , wherein the first mask and the second mask are the same mask. 
     
     
         9 . The method according to  claim 7 , further comprising generating a three-dimensional image of the scene from the first image of the scene and the second image of the scene. 
     
     
         10 . The method according to  claim 7 , wherein:
 the first mask generates a first point spread function from the second light from the scene that varies based on depth within the scene; and   the second mask generates a second point spread function from the fourth light from the scene that varies based on depth within the scene.   
     
     
         11 . The method according to  claim 10 , wherein either or both the first point spread function and the second point spread function comprises a point spread function selected from the list consisting of a double helix point spread function, a helical point spread function, an extended depth of field point spread function, and a cubic phase point spread function. 
     
     
         12 . The method according to  claim 7 , wherein the first light pattern includes a pattern selected from the list consisting of a spot array pattern, a striped pattern, a sinusoidal pattern, and a speckle pattern; and wherein the second light pattern includes a pattern selected from the list consisting of a spot array pattern, a striped pattern, a sinusoidal pattern, and a speckle pattern. 
     
     
         13 . The method according to  claim 7 , wherein either or both the first mask and the second mask include an optical element selected from the list consisting of an optical element with an extended depth of field, a cubic phase mask, a double helix point spread function mask, diffractive optical element, a grating, a Dammann grating, a diffuser, a phase mask, a hologram, an amplitude mask, a spatial light modulator, and a prism array. 
     
     
         14 . A method comprising:
 illuminating a scene with first light having a pattern, the pattern encoding information in a coherence function, or in the polarization state of the pattern;   directing second light from the scene through an optical system that includes a mask that generates a point spread function that varies based on depth within the scene, wherein the second light comprises light provided by the scene responsive to illumination by the first light;   producing an image of the scene from the second light that passes through the mask using a light detector; and   estimating a depth of one or more objects within the scene from the image of the scene.   
     
     
         15 . The method according to  claim 14 , wherein the pattern includes a pattern selected from the list consisting of a spot array pattern, a striped pattern, a sinusoidal pattern, a pattern of a sparse set of spots, dynamically changing spot pattern, a scanning spot pattern, a pattern of spots that move independently, and a speckle pattern. 
     
     
         16 . The method according to  claim 14 , wherein the depth of the one or more objects is estimated based on the representation of the point spread function in the image of the scene. 
     
     
         17 . The method according to  claim 14 , wherein the point spread function comprises a double helix point spread function. 
     
     
         18 . The method according to  claim 14 , wherein the mask includes an optical element selected from the list consisting of an optical element with an extended depth of field, a cubic phase mask, a double helix point spread function mask, diffractive optical element, a grating, a Dammann grating, a diffuser, a phase mask, a hologram, an amplitude mask, a spatial light modulator, and a prism array. 
     
     
         19 . An imaging system, comprising:
 a laser;   an optical system including a mask, the optical system configured to:
 illuminate a scene with first light from the laser, the first light having a pattern, the pattern changing with depth; 
 direct second light from the scene through the mask, wherein the optical system generates a point spread function that varies based on depth within the scene, wherein the second light comprises light provided by the scene responsive to illumination by the first light; 
   a light detector configured to produce an image of the scene from the second light that passes through the mask; and   at least one processor communicatively coupled with the light detector and configured to estimate a depth of one or more objects within the scene from the image of the scene.   
     
     
         20 . The imaging system according to  claim 19 , wherein the pattern includes a pattern selected from the list consisting of a spot array pattern, a striped pattern, a sinusoidal pattern, a pattern of a sparse set of spots, dynamically changing spot pattern, a scanning spot pattern, a pattern of spots that move independently, and a speckle pattern. 
     
     
         21 . The imaging system according to  claim 19 , wherein the depth of the one or more objects is estimated based on the representation of the point spread function in the image of the scene. 
     
     
         22 . The imaging system according to  claim 19 , wherein the point spread function comprises a double helix point spread function. 
     
     
         23 . The imaging system according to  claim 19 , wherein the mask includes an optical element selected from the list consisting of an optical element with an extended depth of field, a cubic phase mask, a double helix point spread function mask, diffractive optical element, a grating, a Dammann grating, a diffuser, a phase mask, a hologram, an amplitude mask, a spatial light modulator, and a prism array. 
     
     
         24 . The imaging system according to  claim 19 , wherein the second light is the result of one or more of the following: scattering, transmission, absorption, fluorescence, two or multi-photon fluorescence, high harmonic generation, refraction, and/or diffraction at or from the objects of the scene.