System architecture design for time-of-flight system having reduced differential pixel size, and time-of-flight systems so designed
First Claim
1. A method performed by an electronic processor to enhance performance of a time-of-flight (TOF) system that emits optical energy and detects with an array of pixels, each pixel occupying less than 20 μ
- m×
20 μ
m in pixel area on an IC substrate, at least a fraction of said optical energy reflected by a target object a distance Z away, the method including the following steps;
(a) digitizing analog detection data obtained from at least some of said pixels during a first operating regime during which at least some of said pixels detect reflected emitted said optical energy during a first integration time interval T1, said digitizing analog detection data obtained from at least some of said pixels during a first operating regime includes acquiring at said TOF system analog detection data during said first operating regime;
(b) digitizing analog detection data obtained from at least some of said pixels during a second operating regime during which at least some of said pixels detect reflected emitted said optical energy during a second integration time interval T2, said digitizing analog detection data obtained from at least some of said pixels during a second operating regime includes acquiring at said TOF system analog detection data during said second operating regime;
(c) combining said digitized analog detection data obtained during said first operating regime and during said second operating regime, wherein relative to a different TOF system that uses digitized data during a single detection integration time interval T1+T2, detection performance of said TOF system is enhanced in at least one aspect selected from the group consisting of detection dynamic differential dynamic range, motion blur, 0°
-180°
offset cancellation, and aliasing interval; and
(d) outputting three-dimensional information based on said combining, wherein operation of said TOF system is determined by a sequence of symbols, said symbols having at least one characteristic selected from a group consisting of (i) at least one symbol in said sequence is associated with a set of pixel waveforms to be applied to a pixel when said symbol is interpreted to be present, and (ii) at least some said symbols and at least some said waveforms are at least one of modifiable and creatable upon download to said TOF of further parameters.
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Abstract
Embodiments of the present invention provide methods to produce a high performance, feature rich TOF system, phase-based or otherwise using small TOF pixels, single-ended or preferably differential, as well as TOF systems so designed. IC chip area required for pixels is reduced by intelligently off-loading or removing from within the pixel certain components and/or functionality. In some embodiments during a single TOF system capture period, analog values from each pixel are repeatedly sampled and converted to digital values, which are combined and manipulated on the sensor chip. Combining this plurality of values enables appropriately compact data from the sensor chip. Embodiments of the present invention implement a TOF system with high ambient light resilience, high dynamic range, low motion blur and dealiasing support, while advantageously reducing pixel area size relative to prior art TOF pixels.
32 Citations
20 Claims
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1. A method performed by an electronic processor to enhance performance of a time-of-flight (TOF) system that emits optical energy and detects with an array of pixels, each pixel occupying less than 20 μ
- m×
20 μ
m in pixel area on an IC substrate, at least a fraction of said optical energy reflected by a target object a distance Z away, the method including the following steps;(a) digitizing analog detection data obtained from at least some of said pixels during a first operating regime during which at least some of said pixels detect reflected emitted said optical energy during a first integration time interval T1, said digitizing analog detection data obtained from at least some of said pixels during a first operating regime includes acquiring at said TOF system analog detection data during said first operating regime; (b) digitizing analog detection data obtained from at least some of said pixels during a second operating regime during which at least some of said pixels detect reflected emitted said optical energy during a second integration time interval T2, said digitizing analog detection data obtained from at least some of said pixels during a second operating regime includes acquiring at said TOF system analog detection data during said second operating regime; (c) combining said digitized analog detection data obtained during said first operating regime and during said second operating regime, wherein relative to a different TOF system that uses digitized data during a single detection integration time interval T1+T2, detection performance of said TOF system is enhanced in at least one aspect selected from the group consisting of detection dynamic differential dynamic range, motion blur, 0°
-180°
offset cancellation, and aliasing interval; and(d) outputting three-dimensional information based on said combining, wherein operation of said TOF system is determined by a sequence of symbols, said symbols having at least one characteristic selected from a group consisting of (i) at least one symbol in said sequence is associated with a set of pixel waveforms to be applied to a pixel when said symbol is interpreted to be present, and (ii) at least some said symbols and at least some said waveforms are at least one of modifiable and creatable upon download to said TOF of further parameters. - View Dependent Claims (2, 3, 4, 5)
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6. An enhanced performance time-of-flight (TOF) system that emits optical energy and detects with an array of pixels at least a fraction of said optical energy reflected by a target object a distance Z away, the TOF system including:
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a plurality of pixels, formed on said array, at least some of said pixels having a pixel area occupying less than 20 μ
m×
20 μ
m in pixel area on an IC substrate that includes said array;first means for digitizing analog detection data obtained from at least some of said pixels during a first operating regime during which at least some of said pixels detect reflected emitted said optical energy during a first integration time interval T1; second means for digitizing analog detection data obtained from at least some of said pixels during a second operating regime during which at least some of said pixels detect reflected emitted said optical energy during a second integration time interval T2; means for combining a digital output from said first means for digitizing and a digital output from said second means for digitizing, wherein relative to a TOF system that uses digitized data during a single detection integration time interval T1+T2, detection performance of said TOF system is enhanced in at least one aspect selected from detection dynamic differential dynamic range, motion blur, 0°
-180°
offset cancellation, and aliasing interval, wherein said IC substrate includes digital bitlines and clock lines, and further including means for switching said bit lines and said clock lines to reduce effects of noise introduced by digitizing data, wherein a signal-to-noise ratio is enhanced. - View Dependent Claims (7, 8, 9)
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10. A method performed by an electronic processor for detecting motion utilizing a time-of-flight (TOF) system, comprising:
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performing a sequence of operations, said sequence of operations includes a first operation and a second operation, said first operation includes digitizing a first set of analog data acquired from one or more pixel detectors during a first operating regime, said second operation includes digitizing a second set of analog data acquired from said one or more pixel detectors during a second operating regime, said sequence of operations structured to prevent a saturation of said one or more pixel detectors by changing a direction of accumulation during said sequence of operations; combining said digitized first set of analog data and said digitized second set of analog data in such a way that said combining implements at least one of reducing motion blur, performing 0°
-180°
offset cancellation, or dealiasing; andoutputting three-dimensional information based on said combining. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification