Position detection using directed light events
A system includes an event-driven type vision sensor that outputs an event signal indicating a two-dimensional position which is located within a field of view of the vision sensor and at which a light intensity change has occurred in a space, and a time of day at which the light intensity change has occurred, a light source that emits light having directivity toward the space, and a position detecting device including an event signal receiving section that receives the event signal, and a position detecting section that detects a three-dimensional position of the light intensity change on the basis of an angle at which the light source has emitted the light at the time of day, the two-dimensional position, and a positional relation between the vision sensor and the light source.
1 . A method comprising:
receiving, from a vision sensor configured to output an event signal indicating a two-dimensional position which is located within a field of view of the vision sensor and at which a light intensity change has occurred in a three-dimensional space, the event signal and a time of day at which the light intensity change has occurred;
adjust a directivity angle for emitting light from a light source towards the three-dimensional space, the emitted light having a form defining an anterior angle and a posterior angle corresponding respectively to an anterior edge and a posterior edge of the emitted light such that a known difference between the anterior angle and the posterior angle is maintained as the directivity angle is adjusted;
determine a three-dimensional position of an object based on (i) detecting a first three-dimensional position of a first light intensity change associated with the anterior edge of the emitted light and (ii) detecting a second three-dimensional position of a second light intensity change associated with the posterior edge of the emitted light; and
detecting a plurality of three-dimensional positions corresponding to a plurality of event signals occurring at different times, thereby enabling time-series tracking of the object in the three-dimensional space.
2 . A system comprising:
a vision sensor configured to output an event signal indicating a two-dimensional position which is located within a field of view of the vision sensor and at which a light intensity change has occurred in a three-dimensional space, and a time of day at which the light intensity change has occurred;
a light source configured to adjust a first angle for emitting light based on the time of day, the light having a directivity toward the three-dimensional space, the emitted light having a form defining an anterior angle and a posterior angle corresponding respectively to an anterior edge and a posterior edge of the emitted light such that a known difference between the anterior angle and the posterior angle is maintained as the first angle is adjusted; and
a position detecting device configured to receive the event signal, the position detecting device further configured to determine a three-dimensional position of an object based on (i) detecting a first three-dimensional position of a first light intensity change associated with the anterior edge of the emitted light and (ii) detecting a second three-dimensional position of a second light intensity change associated with the posterior edge of the emitted light,
wherein the position detecting device is further configured to detect a plurality of three-dimensional positions corresponding to a plurality of event signals occurring at different times, thereby enabling time-series tracking of the object in the three-dimensional space.
3 . The system according to claim 2 , wherein the light source is configured to change the first angle in a time-series pattern.
4 . The system according to claim 3 , wherein the time-series pattern includes changing the first angle in each of two directions intersecting with each other in the three-dimensional space.
5 . The system according to claim 2 , wherein the light source is configured to emit the light having directivity in a form having a width that increases with distance from the light source,
the position detecting device further configured to receive a first event signal indicating an increase of the light intensity and a second event signal indicating a decrease of the light intensity, and
the position detecting device further configured to (i) detect the first three-dimensional position based on the anterior angle of the anterior edge of the light having directivity at the time of day indicated by the first event signal, the two-dimensional position indicated by the first event signal, and a positional relation between the vision sensor and the light source, (ii) detect the second three-dimensional position based on the posterior angle of the posterior edge of the light having directivity at the time of day indicated by the second event signal, the two-dimensional position indicated by the second event signal, and the positional relation, and (iii) determine the three-dimensional position based on an average of the first three-dimensional position and the second three-dimensional position.
6 . The system according to claim 2 , wherein the light source is configured to emit the light having directivity in a form of a band,
the position detecting device further configured to receive a first event signal indicating an increase of the light intensity and a second event signal indicating a decrease of the light intensity, and
the position detecting device further configured to (i) detect the first three-dimensional position based on the anterior angle of the anterior edge of the light having directivity at the time of day indicted by the first event signal, the two-dimensional position indicated by the first event signal, and a positional relation between the vision sensor and the light source, (ii) detect the second three-dimensional position based on the posterior angle of the posterior edge of the light having directivity at the time of day indicated by the second event signal, the two-dimensional position indicated by the second event signal, and the positional relation, and (iii) handle the first three-dimensional position and the second three-dimensional position as time-series changes of the three-dimensional position.
7 . The system according to claim 2 , wherein determining the three-dimensional position of the object based on the first three-dimensional position and the second three-dimensional position associated with the same emitted light increases an accuracy of the determining of the three-dimensional position of the object.
8 . A system comprising:
a processor; and
a computer-readable medium having stored thereon instructions that, when executed with the processor, cause the system to:
receive, from a vision sensor configured to output an event signal indicating a two-dimensional position which is located within a field of view of the vision sensor and at which a light intensity change has occurred in a three-dimensional space, the event signal and a time of day at which the light intensity change has occurred;
adjust a directivity angle for emitting light from a light source towards the three-dimensional space, the emitted light having a form defining an anterior angle and a posterior angle corresponding respectively to an anterior edge and a posterior edge of the emitted light such that a known difference between the anterior angle and the posterior angle is maintained as the directivity angle is adjusted;
determine a three-dimensional position of an object based on (i) detecting a first three-dimensional position of a first light intensity change associated with the anterior edge of the emitted light and (ii) detecting a second three-dimensional position of a second light intensity change associated with the posterior edge of the emitted light; and
detect a plurality of three-dimensional positions corresponding to a plurality of event signals occurring at different times, thereby enabling time-series tracking of the object in the three-dimensional space.
9 . A non-transitory, computer readable storage medium containing a program, which when executed, causes a computing device to, at least:
receive, from a vision sensor configured to output an event signal indicating a two-dimensional position which is located within a field of view of the vision sensor and at which a light intensity change has occurred in a three-dimensional space, the event signal and a time of day at which the light intensity change has occurred;
adjust a directivity angle for emitting light from a light source towards the three-dimensional space, the emitted light having a form defining an anterior angle and a posterior angle corresponding respectively to an anterior edge and a posterior edge of the emitted light such that a known difference between the anterior angle and the posterior angle is maintained as the directivity angle is adjusted;
determine a three-dimensional position of an object based on (i) detecting a first three-dimensional position of a first light intensity change associated with the anterior edge of the emitted light and (ii) detecting a second three-dimensional position of a second light intensity change associated with the posterior edge of the emitted light; and
detect a plurality of three-dimensional positions corresponding to a plurality of event signals occurring at different times, thereby enabling time-series tracking of the object in three-dimensional space.