Method and system to correct motion blur and reduce signal transients in time-of-flight sensor systems

For use with a time-of-flight (TOF) system that emits at least first and second periodic signals of optical energy spaced apart in phase by at least about 90° and that determines distance Z to a target object by detecting and examining relative phase shift in optical energy signals reflected from the target object, a method to reduce motion blur resulting from relative motion between said TOF system and said target object, the method comprising the following steps:

• (a) providing an array of blocks of four pixel detectors, each pixel detector comprising an optical energy collection area, an associated logic circuit, and an associated storage region to store collected charge detected by said pixel detector;
• and
• (b) providing a phase clock unit outputting to each of said blocks at least two clock phase signals spaced-apart by at least about 90°;
• each said logic circuit coupled to receive one of said clock phase signals and delaying as required the received clock phase signal such that adjacent pixel detectors receive a clock phase signal shifted 90° from adjacent pixel detectors;
• each said storage region receiving accumulated detection-generated charge when the associated pixel detector receives an active state clock phase signal.

In a time-of-flight (TOF) system that emits at least first and second periodic signals of optical energy spaced apart in phase by at least about 90° and that determines distance Z to a target object by detecting and examining relative phase shift in optical energy signals reflected from the target object, a detection system comprising:

• an array of pixel detectors, each pixel detector comprising an optical energy collection area larger than a conventional pixel detector collection area by a factor of about four, an associated logic circuit, and four associated storage regions to store collected charge detected by said pixel detector;
• and
• a phase clock unit outputting to each said pixel detector a common clock phase signal from which said associated logic circuit generates four clock phase signals spaced-apart from each other by at least about 90°;
• each said storage region receiving accumulated detection-generated charge when one of said four clock phase signals is in an active state.

For use with a time-of-flight (TOF) system that emits at least first and second periodic signals of optical energy spaced apart in phase by at least about 90° and that determines distance Z to a target object by detecting and examining relative phase shift in optical energy signals reflected from the target object, a method to reduce at least one of motion blur resulting from relative motion between said TOF system and said target object, and phase clock switching transients, the method comprising the following steps:

• (a) providing an array of pixel detectors, each pixel detector comprising an optical energy collection area larger than a conventional pixel detector collection area by a factor of about four, an associated logic circuit, and four associated storage regions to store collected charge detected by said pixel detector;
• and
• (b) outputting to each pixel detector a common clock phase signal from which said associated logic circuit generates four clock phase signals spaced-apart from each other by at least about 90°;
• each of said storage region receiving accumulated detection-generated charge when one of said four clock phase signals is in an active state.

For use with a time-of-flight (TOF) system that emits at least first and second periodic signals of optical energy spaced apart in phase by at least about 90° and that determines distance Z to a target object by detecting and examining relative phase shift in optical energy signals reflected from the target object, a method to reduce at least one of motion blur resulting from relative motion between said TOF system and said target object, and clock signal transients, the method comprising the following steps:

• (a) providing a detection system comprising an array of blocks of four pixel detectors, each pixel detector comprising four optical energy collection areas, four storage regions, each of said regions associated with one of said four optical energy collection area to store collected charge detected by said pixel detector, and a common logic circuit coupled to receive from said TOF system a single clock phase signal and to generate therefrom and couple to said pixel detectors four clock signals phase-shifted from each other by about 90°;
• and
• (b) providing said single clock phase signal from said TOF system;
• each of said storage regions receiving accumulated detection-generated charge when an associated collection area of said pixel detector receives an active state clock phase signal;
• wherein relative to a TOF system that requires more phase clock cycles for detection said method reduces at least one of motion blur measurement error due to relative motion between said detection system and said target object, and signal integrity error resulting from clock switching transients.