Methods and system to quantify depth data accuracy in three-dimensional sensors using single frame capture
First Claim
1. For use in a phase-shift time-of-flight (TOF) system that emits signals of optical energy and determines distance Z to a target object by detecting and examining relative phase shift in optical energy signals reflected from the target object and detected by an array of pixel photodetectors, a method to assign a measure of confidence to output signals detected by said photodetectors, the method including the following steps:
- (a) acquiring during a time frame from said photodetectors active brightness data and total brightness data;
(b) storing a priori-determined at least one of upper and lower detectable levels of optical energy for at least some of said photodetectors;
(c) comparing levels stored at step (b) with presently generated output signals from said at least some photodetectors to identify which, if any, of said photodetectors is presently operating other than in an acceptable dynamic range; and
(d) characterizing Z depth information obtained by output from said at least some detectors as being at least one of questionable confidence and acceptable confidence.
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Accused Products
Abstract
A method and system dynamically calculates confidence levels associated with accuracy of Z depth information obtained by a phase-shift time-of-flight (TOF) system that acquires consecutive images during an image frame. Knowledge of photodetector response to maximum and minimum detectable signals in active brightness and total brightness conditions is known a priori and stored. During system operation brightness threshold filtering and comparing with the a priori data permits identifying those photodetectors whose current output signals are of questionable confidence. A confidence map is dynamically generated and used to advise a user of the system that low confidence data is currently being generated. Parameter(s) other than brightness may also or instead be used.
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Citations
20 Claims
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1. For use in a phase-shift time-of-flight (TOF) system that emits signals of optical energy and determines distance Z to a target object by detecting and examining relative phase shift in optical energy signals reflected from the target object and detected by an array of pixel photodetectors, a method to assign a measure of confidence to output signals detected by said photodetectors, the method including the following steps:
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(a) acquiring during a time frame from said photodetectors active brightness data and total brightness data; (b) storing a priori-determined at least one of upper and lower detectable levels of optical energy for at least some of said photodetectors; (c) comparing levels stored at step (b) with presently generated output signals from said at least some photodetectors to identify which, if any, of said photodetectors is presently operating other than in an acceptable dynamic range; and (d) characterizing Z depth information obtained by output from said at least some detectors as being at least one of questionable confidence and acceptable confidence. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. For use in a phase-shift time-of-flight (TOF) system that emits signals of optical energy and determines distance Z to a target object by detecting and examining relative phase shift in optical energy signals reflected from the target object and detected by an array of pixel photodetectors, said TOF system acquiring active brightness data and total brightness data, a confidence system to assign a measure of confidence to output signals detected by said photodetectors, the confidence system comprising:
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memory to store a priori-determined at least one of upper and lower detectable levels of optical energy for at least some of said photodetectors; means for comparing at least some of said stored said upper and lower detectable levels with presently generated output signals from said at least some photodetectors to identify which, if any, of said photodetectors is presently operating other than in an acceptable dynamic range; and means for characterizing Z depth information obtained by output from said at least some detectors as being at least one of questionable confidence and acceptable confidence. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A phase-shift time-of-flight (TOF) system that emits signals of optical energy and determines distance Z to a target object by detecting and examining relative phase shift in optical energy signals reflected from the target object and detected by an array of pixel photodetectors wherein said TOF system acquires active brightness data and total brightness data, said TOF system further including:
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a confidence system to assign a measure of confidence to output signals detected by said photodetectors, the confidence system comprising; memory to store a priori-determined at least one of upper and lower detectable levels of optical energy for at least some of said photodetectors; means for comparing at least some of said stored said upper and lower detectable levels with presently generated output signals from said at least some photodetectors to identify which, if any, of said photodetectors is presently operating other than in an acceptable dynamic range; and means for characterizing Z depth information obtained by output from said at least some detectors as being at least one of questionable confidence and acceptable confidence. - View Dependent Claims (20)
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Specification