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1. EP2729826 - IMPROVEMENTS IN OR RELATING TO THE PROCESSING OF TIME-OF-FLIGHT SIGNALS

Office
European Patent Office
Application Number 13700548
Application Date 10.01.2013
Publication Number 2729826
Publication Date 14.05.2014
Publication Kind B1
IPC
G01S 7/486
GPHYSICS
01MEASURING; TESTING
SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
7Details of systems according to groups G01S13/, G01S15/, G01S17/127
48of systems according to group G01S17/58
483Details of pulse systems
486Receivers
G01S 17/89
GPHYSICS
01MEASURING; TESTING
SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
17Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
88Lidar systems, specially adapted for specific applications
89for mapping or imaging
CPC
G01S 7/4865
GPHYSICS
01MEASURING; TESTING
SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
7Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
48of systems according to group G01S17/00
483Details of pulse systems
486Receivers
4865Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak
G01S 17/89
GPHYSICS
01MEASURING; TESTING
SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
17Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
88Lidar systems specially adapted for specific applications
89for mapping or imaging
G01S 17/894
GPHYSICS
01MEASURING; TESTING
SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
17Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
88Lidar systems specially adapted for specific applications
89for mapping or imaging
8943D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
G01S 17/02
GPHYSICS
01MEASURING; TESTING
SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
17Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
02Systems using the reflection of electromagnetic waves other than radio waves
H04N 25/60
Applicants SOFTKINETIC SENSORS N V
Inventors VAN NIEUWENHOVE DANIEL
VAN DEN HAUWE TOMAS
GROOTJANS RIEMER
VAN DER TEMPEL WARD
Designated States
Priority Data 12150687 10.01.2012 EP
13700548 10.01.2013 EP
Title
(DE) VERBESSERUNGEN AN ODER IM ZUSAMMENHANG MIT DER VERARBEITUNG VON TOF-SIGNALEN
(EN) IMPROVEMENTS IN OR RELATING TO THE PROCESSING OF TIME-OF-FLIGHT SIGNALS
(FR) AMÉLIORATIONS APPORTÉES OU SE RAPPORTANT AU TRAITEMENT DES SIGNAUX DE TEMPS DE VOL
Abstract
(EN) Described herein is a method and sensor of processing time-of-flight (TOF) signals in a TOF camera system including an illumination unit and an imaging sensor. The method comprises illuminating the scene with light at a first frequency, detecting reflected light from at least one object in the scene at the first frequency, and determining a phase measurement using I and Q values. In addition, the scene is illuminated with light at a second frequency, the second frequency being 2-n of the first frequency where n=1, 2,..., etc., and the signs of I and Q values for both the first and second frequencies is used to determine the presence of aliasing in the phase measurement so that it can be corrected. The phase measurement is then corrected for aliasing and the effective range of the TOF camera system is extended by multiples of 2n. In addition, relative signal strength needs to be considered in accordance with the reflectivity of objects within the scene. For a reflectivity of 4% and no aliasing, the ability to detect an object decreases with distance (30). For an aliased phase measurement for an object with a reflectivity of 100%, the ability to detect the object is substantially constant (35).
(FR) La présente invention concerne un procédé et un capteur de traitement de signaux de temps de vol (TOF) dans un système de caméra TOF comprenant une unité d'éclairage et un capteur d'imagerie. Le procédé comprend l'éclairage d'un lieu avec une lumière à une première fréquence, la détection de la lumière réfléchie par au moins un objet se trouvant dans le lieu à la première fréquence, et la détermination d'une mesure de phase au moyen des valeurs I et Q. Le lieu est également éclairé par une lumière à une seconde fréquence, la seconde fréquence étant égale à 2-n par rapport à la première fréquence (avec n = 1, 2,..., etc.), et les signes des valeurs I et Q pour la première et la seconde fréquence sont utilisés pour déterminer la présence d'un repliement dans la mesure de phase de façon à ce qu'elle puisse être corrigée. La mesure de phase est ensuite corrigée pour le repliement et la gamme effective du système de caméra TOF est étendue par des multiples de 2n. De plus, l'intensité relative du signal doit être prise en compte en fonction de la réflectivité des objets se trouvant dans le lieu. Pour une réflexivité de 4 % et sans repliement, la capacité de détection d'un objet diminue avec la distance (30). Pour une mesure de phase avec repliement pour un objet ayant une réflexivité de 100 %, la capacité de détection de l'objet est sensiblement constante (35).