Multi-band homodyne encoder

Patent metadata

Field	Value
Publication number	US-12047549-B2
Application number	US-202217873010-A
Country	US
Kind code	B2
Filing date	Jul 25, 2022
Priority date	Jul 25, 2022
Publication date	Jul 23, 2024
Grant date	Jul 23, 2024

Abstract

A homodyne encoder encodes light sampled from an object with respective primary apertures for each spectral band. The multi-band homodyne encoder includes an optical spreader and a focusing optic. The optical spreader spreads apart the light from the respective primary apertures for each spectral band to respective secondary apertures for each spectral band. The optical spreader is arranged to spread, for each spectral band, the light from each one of the primary apertures for the spectral band to a respective one of the secondary apertures for the spectral band. The focusing optic focuses the light from the secondary apertures for all of the spectral bands into one or more composite images of the object. For each spectral band, every pairing of two of the primary apertures for the spectral band contributes distinct spatial frequencies to the composite image or images of the object.

First claim

We claim:

1. A multi-band homodyne encoder for encoding light sampled from an object with a respective plurality of primary apertures for each of a plurality of spectral bands, the multi-band homodyne encoder comprising:
an optical spreader for spreading apart the light from the respective plurality of primary apertures for the each of the plurality of spectral bands to a respective plurality of secondary apertures for each of the plurality of spectral bands, the optical spreader arranged to spread, for each spectral band of the plurality of spectral bands, the light from each one of the respective plurality of primary apertures for the each spectral band to a respective one of the secondary apertures for the each spectral band; and
a focusing optic for focusing the light from the plurality of secondary apertures for all of the plurality of spectral bands into at least one composite image of the object, wherein, for the each spectral band of the plurality of spectral bands, every pairing of two of the plurality of primary apertures for the each spectral band contributes distinct spatial frequencies to said at least one composite image of the object.

2. The multi-band homodyne encoder of claim 1 , wherein the optical spreader is arranged to spread apart the light from the respective plurality of primary apertures for all of the plurality of spectral bands into the respective plurality of secondary apertures for all of the plurality of spectral bands by at least twice a baseline separation among the primary apertures for each of the plurality of spectral bands.

3. The multi-band homodyne encoder of claim 1 , wherein:
the plurality of spectral bands is m spectral bands;
the primary apertures for all of the m spectral bands consists of n×m primary apertures including n primary apertures for each of the m spectral bands; and
the secondary apertures for all of the m spectral bands consists of n×m secondary apertures including n secondary apertures for each of the m spectral bands, wherein m and n are integers greater than or equal to 2.

4. The multi-band homodyne encoder of claim 1 , wherein:
the respective plurality of primary apertures for each one of the plurality of spectral bands is three primary apertures for said one of the plurality of spectral bands;
the respective plurality of secondary apertures for each one of the plurality of spectral bands is three secondary apertures for said one of the plurality of spectral bands; and,
for the each spectral band of the plurality of spectral bands, the distinct spatial frequencies of three different pairings of the two of the three primary apertures for the spectral band specify a piston, tip, and tilt distortion of said at least one composite image, with the piston, tip, and tilt distortion including an atmospheric distortion from an atmosphere between the object and the multi-band homodyne encoder.

5. The multi-band homodyne encoder of claim 4 , wherein, for each particular spectral band of the plurality of spectral bands:
the distinct spatial frequencies of each of the three different pairings of a first and second one of the two of the three primary apertures for the each particular spectral band describe an interference pattern between the light received from the object through the first and second one of the three primary apertures for the each particular spectral band; and
the interference pattern from the three different pairings for the each particular spectral band specify the piston, tip, and tilt distortion of said at least one composite image in the each particular spectral band.

6. The multi-band homodyne encoder of claim 4 , further comprising:
a sensor with a two-dimensional array of pixels for detecting, for at least one of the plurality of spectral bands, said at least one composite image of the object; and
electronic circuitry for separating, for said at least one of the plurality of spectral bands, the distinct spatial frequencies across the two-dimensional array of pixels, and for compensating, for said at least one of the plurality of spectral bands, the piston, tip, and tilt distortion of said at least one composite image in response to the distinct spatial frequencies separated across the two dimensional array of pixels.

7. The multi-band homodyne encoder of claim 1 , wherein:
the respective plurality of primary apertures for each of the plurality of spectral bands is three circular primary apertures surrounding an axis through the multi-band homodyne encoder, wherein the three circular primary apertures for each of the plurality of spectral bands have a first baseline separation;
the respective plurality of secondary apertures for each of the plurality of spectral bands is three circular secondary apertures surrounding the axis, wherein the three circular secondary apertures for each of the plurality of spectral bands have a second baseline separation, and the three circular secondary apertures for all of the plurality of spectral bands form a non-redundant array;
the optical spreader includes a first and second set of diffractive optical elements for transposing the light passing through the three circular primary apertures for all of the plurality of spectral bands radially and circumferentially away from the axis so that the second baseline separation is at least twice the first baseline separation, wherein, for each spectral band of the plurality of spectral bands, a respective diffractive optical element in the first set for each of the three circular primary apertures for the spectral band diffracts the light radially and circumferentially away from the axis and subsequently a respective diffractive optical element in the second set equally diffracts the light back towards the axis and into a respective one of the three circular secondary apertures for the spectral band; and
the focusing optic is a lens for focusing the light passing through the non-redundant array from the optical spreader into said at least one composite image.

8. The multi-band homodyne encoder of claim 1 , wherein:
the plurality of spectral bands is two spectral bands including a first and second spectral band;
the primary apertures for both of the first and second spectral bands are six primary apertures, which include three primary apertures for each of the first and second spectral bands;
the secondary apertures for both of the first and second spectral bands are six secondary apertures, which include three secondary apertures for each of the first and second spectral bands; and
the optical spreader is arranged to spread apart the light sufficiently so said at least one composite image from the focusing optic includes the distinct spatial frequencies for each of three different pairings of the two of the three primary apertures for each of the first and second spectral bands, the distinct spatial frequencies for the three different pairings specifying a piston, tip, and tilt distortion of said at least one composite image.

9. The multi-band homodyne encoder of claim 8 , further comprising:
a sensor with a two-dimensional array of pixels, which each include a first and second filtered subpixel for respectively detecting the first and second spectral bands in said at least one composite image; and
electronic circuitry for separating the distinct spatial frequencies for the first spectral band from the first filtered subpixel across the two-dimensional array of pixels and for separating the distinct spatial frequencies for the second spectral band from the second filtered subpixel across the two-dimensional array of pixels, and for compensating, for both the first and second spectral bands, the piston, tip, and tilt distortion of said at least one composite image in response to

Assignees

• Us Navy
• Us Navy

Inventors

• Drexler Kyle Robert
• Laxton Benjamin

Classifications

• H04N13/214 Primary

  using spectral multiplexing · CPC title

• H04N23/957 Primary

  Light-field or plenoptic cameras or camera modules · CPC title