High frame rate interleaved imagers
Two or more imagers having associated frame rates are each configured with a global shutter having an exposure interval less than a frame interval. The exposure interval for a first imager is offset from the exposure interval of a second imager such that the first imager is exposed while the second imager is not exposed. When interleaved, an effective frame rate exceeds the individual frame rates provided by the individual imagers. This interleaved imaging system may be used to recover, at high frame rates, images that are projected from spatial light modulators.
1. An imaging system comprising:
a first global shutter coupled to a first imager having a first frame rate;
a second global shutter coupled to a second imager having a second frame rate; and
an imaging controller configured to:
capture first image data from the first imager based on a first exposure interval of the first global shutter with a duration less than the first frame rate;
capture second image data from the second imager based on a second exposure interval of the second global shutter with a duration less than the second frame rate; and
interleave the first exposure interval and the second exposure interval to generate an effective frame rate greater than the first frame rate or the second frame rate.
2. The system of claim 1 , wherein the first exposure interval and the second exposure interval overlap.
3. The system of claim 2 , wherein the first exposure interval is offset from the second exposure interval such that the first image data is captured while the second image data is not captured.
4. The system of claim 1 , wherein the global shutters are configured to: (1) expose substantially all of an imaging portion of the respective imager at about the same time during the first exposure interval and the second exposure interval, and (2) substantially prevent exposure of the imaging portion of the respective image outside the first exposure interval and the second exposure interval.
5. The system of claim 1 , wherein the global shutters comprise electronic global shutters configured to continually pass illumination to a respective imager.
6. The system of claim 1 , wherein the first frame rate and the second frame rate are about the same value but offset from one another by a pre-determined interleaving offset time interval.
7. The system of claim 1 , wherein the first frame rate and the second frame rate are about 60 frames per second and the first and second exposure intervals are about 1/120 of a second.
8. The system of claim 1 , wherein the imaging controller is further configured to recover an image comprising a projected image; and further comprising a spatial light modulator configured to project at least a portion of the projected image.
9. The system of claim 8 , wherein the spatial light modulator comprises a digital micromirror device.
10. The system of claim 8 , wherein the projected image comprises structured light.
11. The system of claim 8 , wherein the effective frame rate is between about 60 frames per second and about 240 frames per second.
12. An imaging system comprising:
a plurality of imaging elements configured to share at least a portion of an optical path, each of the plurality of imaging elements being coupled to a respective global shutter to pass illumination to each of the plurality of imaging elements; and
an imaging controller configured to interleave respective exposure times of the global shutters across the plurality of imaging elements to generate a frame rate greater than an individual frame rate for each of the plurality of imaging elements.
13. The system of claim 12 , further comprising an additional one or more imaging elements configured to share at least a portion of the optical path, the additional one or more imaging elements being free from a global shutter.
14. The system of claim 12 , wherein a shutter exposure interval of the global shutters is less than or equal to about 1/n of the frame rate of the plurality of imaging elements where n equals a number of imaging elements.
15. The system of claim 12 , wherein one or more of the plurality of imagers are configured to detect infrared light.
16. The system of claim 12 , further comprising a spatial light modulator configured to generate a projected image detectable at least in part by the plurality of imaging elements.
17. One or more non-transitory computer-readable media storing computer-executable instructions that, when executed, cause one or more processors to perform acts comprising:
setting a first global shutter coupled to the first imager having a first frame rate to a first exposure interval, the first global shutter configured to pass illumination to the first imager; and
setting a second global shutter coupled to a second imager having a second frame rate interleaved with the first frame rate to a second exposure interval, the second global shutter configured to pass illumination to the second imager and the second exposure interval alternates with the first exposure interval to generate an effective frame rate greater than the first frame rate and greater than the second frame rate.
18. The one or more non-transitory computer-readable storage media of claim 17 , further comprising:
acquiring interleaved images from the first and second imagers which share at least a portion of a common optical axis;
determining a reference point appearing across the acquired interleaved images; and
aligning the image of the reference point among the interleaved images.
19. The one or more non-transitory computer-readable storage media of claim 18 , wherein the aligning comprises shifting electronically the interleaved images.
20. The one or more non-transitory computer-readable storage media of claim 18 , wherein the aligning comprises mechanically shifting the first imager, second imager, or both the first and second imagers.