Holographic lidar system and method
There is provided a lighting device arranged to produce a controllable light beam for illuminating a scene. The device comprises an addressable spatial light modulator arranged to provide a selectable phase delay distribution to a beam of incident light. The device further comprises Fourier optics arranged to receive phase-modulated light from the spatial light modulator and form a light distribution. The device further comprises projection optics arranged to project the light distribution to form a pattern of illumination as said controllable light beam.
1. A method for performing a light detection and ranging (“LIDAR”) measurement on a scene, comprising:
providing a beam of incident infrared light;
illuminating an addressable spatial light modulator with the beam of incident infrared light;
providing, using the spatial light modulator, a selectable phase delay distribution to the beam of incident infrared light with the addressable spatial modulator to provide an exit beam, the phase delay distribution comprising a representation of a pattern of illumination in the hologram domain, and
performing holographic transformation of the pattern of illumination in the hologram domain, such that the phase-modulated light of the exit beam forms an image in the spatial domain;
projecting the image in the spatial domain to form a pattern of infrared illumination in space, the pattern of infrared illumination in space illuminating the scene; and
detecting infrared illumination reflected from the scene, wherein the detection of infrared illumination reflected from the scene comprises capturing with an infrared detector an image of the scene illuminated with the pattern of infrared illumination in space.
2. The method of claim 1 , further comprising comparing the captured image with the projected pattern of infrared illumination.
3. The method of claim 2 , further comprising detecting an abnormality in the scene based on distortions in the captured image.
4. The method of claim 3 , wherein detecting the abnormality comprises identifying differences between a captured image and a pattern of infrared illumination corresponding to the phase delay distribution.
5. The method of claim 1 , wherein the pattern of infrared illumination in space is in the form of a grid.
6. The method of claim 1 , wherein the incident light is coherent.
7. The method of claim 1 , wherein the incident light has a generally planar wavefront.
8. The method of claim 1 , wherein the phase-modulated light of the exit beam is a phase-only modulated light.
9. The method of claim 1 , wherein the holographic transformation is performed using Fourier optics.
10. The method of claim 1 , wherein the holographic transformation is performed using optics comprising a lens.
11. The method of claim 1 , wherein the pattern of infrared illumination is a regular repeating pattern.
12. The method of claim 3 , further comprising altering one or more vehicle settings in response to the detection of the abnormality.
13. The method of claim 12 , wherein the one or more vehicle settings include one or more of suspension settings and power distribution settings.
14. A method for performing a light detection and ranging (“LIDAR”) measurement on a scene, comprising:
providing a beam of incident infrared light;
illuminating an addressable spatial light modulator with the beam of incident infrared light;
providing, using the spatial light modulator, a selectable phase delay distribution to the beam of incident infrared light with the addressable spatial modulator to provide an exit beam, the phase delay distribution comprising a representation of a pattern of illumination in the hologram domain, and
performing a frequency-space transformation such that the exit beam forms an image in the spatial domain; and
projecting the image in the spatial domain to form a pattern of infrared illumination in space, the pattern of infrared illumination in space illuminating the scene; and
detecting infrared illumination reflected from the scene, wherein the detection of infrared illumination reflected from the scene comprises capturing with an infrared detector an image of the scene illuminated with the pattern of infrared illumination in space.
15. The method of claim 14 , further comprising comparing the captured image with the projected pattern of illumination.
16. The method of claim 14 , further comprising detecting an abnormality in the scene based on distortions in the captured image.
17. The method of claim 16 , wherein detecting the abnormality comprises identifying differences between a captured image and a pattern of infrared illumination corresponding to the phase delay distribution.
18. The method of claim 14 , wherein the pattern of illumination in space is in the form of a grid.
19. The method of claim 14 , wherein the incident light is coherent.
20. The method of claim 14 , wherein the incident light has a generally planar wavefront.
21. The method of claim 14 , wherein the phase-modulated light of the exit beam is a phase-only modulated light.
22. The method of claim 14 , wherein the holographic transformation is performed using Fourier optics.
23. The method of claim 14 , wherein the holographic transformation is performed using optics comprising a lens.