Holographic lidar system

1. A light detection and ranging (“LIDAR”) system, the system comprising

a lighting device arranged to produce a controllable light beam for illuminating a scene, the device comprising:

a source of coherent incident light;

an addressable spatial light modulator arranged to provide a selectable phase delay distribution to a beam of incident light from the source, the phase delay distribution comprising a representation of a pattern of illumination in the Fourier domain;

Fourier optics arranged to receive phase-modulated light from the spatial light modulator and perform a frequency-space transformation upon the received phase-modulated light to form a light distribution; and

projection optics arranged to project the light distribution to form the pattern of illumination as said controllable light.

2. The LIDAR system of claim 1 , wherein the light is infrared light.

3. The LIDAR system of claim 1 , wherein the pattern of illumination comprises a grid pattern.

4. The LIDAR system of claim 1 , further comprising a forward-looking camera arranged to capture an image of the scene.

5. The LIDAR system of claim 4 , wherein the system is arranged to compare the captured image with the projected pattern of illumination.

6. The LIDAR system of claim 4 , wherein the system is arranged to identify differences between the captured image and the projected pattern of illumination.

7. The LIDAR system of claim 1 , wherein the system is arranged to detect an abnormality in the scene.

8. The LIDAR system of claim 1 , wherein the system is arranged to select the phase delay distribution to steer the controllable light beam.

9. The LIDAR system of claim 1 , wherein the system is arranged to select the phase delay distribution to illuminate chosen areas of the scene while not illuminating other areas.

10. The LIDAR system of claim 1 , wherein the system is arranged to read the phase delay distribution from a memory.

11. The LIDAR system of claim 1 , wherein the system is arranged to detect the approximate proximity of the vehicle and modify the selectable phase delay distribution on the spatial light modulator to provide a modified scene-illuminating beam.

12. The LIDAR system of claim 1 , wherein the spatial light modulator is liquid crystal on silicon device.

13. A vehicle comprising the LIDAR system of claim 1 .

14. The LIDAR system of claim 1 , wherein the spatial light modulator is a phase-only spatial light modulator.

15. A method for performing a light detection and ranging (“LIDAR”) measurement on a scene, comprising:

providing a beam of coherent incident light;

illuminating an addressable spatial light modulator with the beam of coherent incident light;

providing, using the spatial light modulator, a selectable phase delay distribution to the beam of coherent incident 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 Fourier domain;

applying the exit beam to Fourier optics to perform a frequency-space transformation upon the received phase-modulated light to form an image in the spatial domain; and

using projection optics to project the image to form a pattern of illumination in space, the pattern of illumination in space illuminating the scene.

16. The method of claim 15 , further comprising capturing an image of the scene illuminated with the pattern of illumination in space.

17. The method of claim 16 , further comprising comparing the captured image with the projected pattern of illumination.

18. The method of claim 15 , further comprising selecting the phase delay distribution to illuminate chosen areas of the scene while not illuminating other areas.

19. The method of claim 15 , further comprising detecting the approximate proximity of a vehicle and modifying the selectable phase delay distribution on the spatial light modulator to provide a modified scene-illuminating beam.

20. The method of claim 15 , comprising dynamically varying the phase delay distribution to steer the controllable light beam.