Self correcting adaptive low light optical payload
First Claim
Patent Images
1. A method for capturing images, the method comprising:
- capturing, during an exposure period with at least one sensor on a moving imaging platform, frames of a scene in a first photon-rich spectral band and in a second photon-poor spectral band having a lower light level than the first photon-rich spectral band, the frames captured in the first photon-rich spectral band and the frames captured in the second photon-poor spectral band including identical image motion induced by a relative motion between the imaging platform and the scene, wherein the relative motion is unknown and not calculated;
calculating one or more transformations based on measured changes in inter-frame scenes captured in the first photon-rich spectral band to compensate for the induced image motion, wherein the induced image motion includes at least one of rotation, scale, and anamorphic stretch;
digitally transforming the captured frames of the second photon-poor spectral band with the one or more transformations compensating for the induced image motion in the frames captured in the second photon-poor spectral band to remove effects of the induced image motion; and
summing a plurality of successive compensated frames captured in the second photon-poor spectral band to obtain higher signal to noise ratio (SNR) imagery in the second photon-poor spectral band compared to successive uncompensated frames captured in the second photon-poor spectral band,wherein capturing frames of the scene comprises interleaving first spectral band exposure times with second spectral band exposure times, the first spectral band exposure times being shorter than the second spectral band exposure times.
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Abstract
Methods and systems are disclosed for compensating for image motion induced by a relative motion between an imaging platform and a scene. During an exposure period, frames of the scene may be captured respectively in multiple spectral bands, where one of the spectral bands has a lower light level than the first spectral band, and contemporaneous frames include a nearly identical induced image motion. Image eigenfunctions are utilized to estimate the induced image motion from the higher SNR spectral band, and compensate in each of the multiple bands.
43 Citations
16 Claims
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1. A method for capturing images, the method comprising:
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capturing, during an exposure period with at least one sensor on a moving imaging platform, frames of a scene in a first photon-rich spectral band and in a second photon-poor spectral band having a lower light level than the first photon-rich spectral band, the frames captured in the first photon-rich spectral band and the frames captured in the second photon-poor spectral band including identical image motion induced by a relative motion between the imaging platform and the scene, wherein the relative motion is unknown and not calculated; calculating one or more transformations based on measured changes in inter-frame scenes captured in the first photon-rich spectral band to compensate for the induced image motion, wherein the induced image motion includes at least one of rotation, scale, and anamorphic stretch; digitally transforming the captured frames of the second photon-poor spectral band with the one or more transformations compensating for the induced image motion in the frames captured in the second photon-poor spectral band to remove effects of the induced image motion; and summing a plurality of successive compensated frames captured in the second photon-poor spectral band to obtain higher signal to noise ratio (SNR) imagery in the second photon-poor spectral band compared to successive uncompensated frames captured in the second photon-poor spectral band, wherein capturing frames of the scene comprises interleaving first spectral band exposure times with second spectral band exposure times, the first spectral band exposure times being shorter than the second spectral band exposure times. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system configured to capture images, comprising:
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a movable imaging platform configured with at least one sensor to capture, during an exposure period, frames of a scene in a first spectral band and in a second spectral band having a lower light level than the first spectral band, the frames captured in the first spectral band and the frames captured in the second spectral band including identical image motion induced by a relative motion between the imaging platform and the scene; a transformation computation processor configured to calculate one or more eigenfunction coefficients based on a fitting of one or more image eigenfunctions to measured changes in inter-frame scenes captured in the first spectral band to compensate for the induced image motion; and an image correction processor configured to digitally transform the captured frames of the second spectral band with one or more eigenfunction transformations and the calculated one or more eigenfunction coefficients, in order to compensate for the image distortion resulting from the induced image motion, wherein the image distortion includes at least one of rotation, scale, and anamorphic stretch; and a fusion processor configured to sum a plurality of successive compensated frames captured in the second spectral band to obtain higher signal to noise ratio (SNR) imagery in the second spectral band compared to successive uncompensated frames captured in the second spectral band, wherein the at least one sensor captures frames of the scene in first spectral band exposure times interleaved with second spectral band exposure times, the first spectral band exposure times being shorter than the second spectral band exposure times. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification