Gated 3D camera
View Patent ↗A camera for determining distances to a scene, the camera comprising: a light source comprising a VCSEL controllable to illuminate the scene with a train of pulses of light having a characteristic spectrum; a photosurface; optics for imaging light reflected from the light pulses by the scene on the photosurface; and a shutter operable to gate the photosurface selectively on and off for light in the spectrum.
1. A camera for determining distances to a scene, the camera comprising:
a light source comprising at least one vertical cavity surface emitting light emitting laser (VCSEL) controllable to illuminate the scene with a train of pulses of light having a characteristic spectrum;
a photosurface;
optics for imaging light reflected from the light pulses by the scene on the photosurface; and
a shutter operable to gate the photosurface selectively on and off for light in the spectrum wherein bias error resulting from a temperature difference between the light source and the shutter is less than about 10 percent of the displacement of an imaging slice of the scene.
2. A camera according to claim 1 wherein the light source has a characteristic spectrum with a FWHM width equal to or greater than about 1.5 nm.
3. A camera according to claim 1 wherein the characteristic spectrum has a FWHM width equal to or greater than about 2.0 nm.
4. A camera according to claim 1 wherein the characteristic spectrum has a FWHM width equal to or greater than about 2.5 nm.
5. A camera according to claim 1 wherein the VCSEL has a lasing cavity characterized by a diameter about equal to or greater than 20 microns.
6. A camera according to claim 1 wherein the VCSEL has a lasing cavity characterized by a diameter about equal to or greater than 25 microns.
7. A camera according to claim 1 wherein a normalized convolution of shutter contrast ratio (CR) and characteristic spectrum is greater than or equal to about 10 for a temperature difference between the shutter and light source less than or equal to about 20° C.
8. A camera according to claim 1 wherein a normalized convolution of shutter contrast ratio (CR) and characteristic spectrum is greater than or equal to about 12 for a temperature difference between the shutter and light source less than or equal to about 20° C.
9. A camera according to claim 1 wherein the light source operates at a power level about equal to or greater than 12 Watts to illuminate the scene with the train of light pulses.
10. A camera according to claim 1 wherein the power level is about equal to or greater than 15 Watts.
11. A camera according to claim 1 wherein the power level is about equal to or greater than 18 Watts.
12. An apparatus for determining distances to a scene, the apparatus comprising:
a light source having an array of VCSELs provides improved matching of the light source to the camera shutter reduced bias errors, controllable to illuminate the scene with a train of pulses of light having a characteristic spectrum;
a photosurface;
a lens system for imaging light reflected from the light pulses by the scene on the photosurface; and
a shutter operable to gate the photosurface selectively on and off for light in the spectrum;
wherein a normalized convolution of shutter contrast ratio (CR) and characteristic spectrum is greater than or equal to about 10 for a temperature difference between the shutter and light source less than or equal to about 20° C.
13. An apparatus according to claim 12 wherein the light source has a characteristic spectrum with a FWHM width equal to or greater than about 1.5 nm.
14. An apparatus according to claim 13 wherein the VCSEL has a lasing cavity characterized by a diameter about equal to or greater than 20 microns.
15. An apparatus according to claim 12 wherein the light source operates at a power level about equal to or greater than 12 Watts to illuminate the scene with the train of light pulses.
16. A camera for determining distances to a scene, the camera comprising:
a light source having an array of VCSELs providing improved matching of the light source to the camera shutter and being controllable to illuminate the scene with a train of pulses of light having a characteristic spectrum, the light source has a characteristic spectrum with a FWHM width equal to or greater than about 1.5 nm, and a lasing cavity characterized by a diameter about equal to or greater than 20 microns;
a controller coupled to the light source;
a photosurface comprising a CCD or CMOS photosensitive surface;
a lens system for imaging light reflected from the light pulses by the scene on the photosurface; and
a shutter operable to gate the photosurface selectively on and off for light in the spectrum;
wherein bias error resulting from a temperature difference between the light source and the shutter is less than about 10 percent of the displacement of an imaging slice of the scene.