APPARATUS FOR ACQUIRING 3-DIMENSIONAL MAPS OF A SCENE
An active sensor for performing active measurements of a scene is presented. The active sensor includes at least one transmitter configured to emit light pulses toward at least one target object in the scene, wherein the at least one target object is recognized in an image acquired by a passive sensor; at least one receiver configured to detect light pulses reflected from the at least one target object; a controller configured to control an energy level, a direction, and a timing of each light pulse emitted by the transmitter, wherein the controller is further configured to control at least the direction for detecting each of the reflected light pulses; and a distance measurement circuit configured to measure a distance to each of the at least one target object based on the emitted light pulses and the detected light pulses.
1 . An active sensor for performing active measurements of a scene, comprising:
at least one transmitter configured to emit light pulses toward at least one target object in the scene, wherein the at least one target object is recognized in an image acquired by a passive sensor;
at least one receiver configured to detect light pulses reflected from the at least one target object;
a controller configured to control an energy level, a direction, and a timing of each light pulse emitted by the transmitter, wherein the controller is further configured to control at least the direction for detecting each of the reflected light pulses; and
a distance measurement circuit configured to measure a distance to each of the at least one target object based on the emitted light pulses and the detected light pulses.
2 . The active sensor of claim 1 , wherein each transmitter further comprises:
a light source configured to emit electromagnetic radiation in at least one wavelength;
a transmitter static light directing circuit (LDC) configured to direct the light pulses emitted by the transmitter in a first plurality of directions; and
at least one transmitter lens.
3 . The active sensor of claim 2 , wherein the transmitter static LDC includes at least one microelectromechanical system (MEMS) mirror.
4 . The active sensor of claim 2 , wherein the transmitter static LDC is any of: an acousto-optic modulator (AOM), and an electro-optic modulator (EOM).
5 . The active sensor of claim 2 , wherein the controller is further configured to cause the transmitter static LDC to change between the first plurality of directions.
6 . The active sensor of claim 2 , wherein the controller is further configured to control the direction of each light pulse by timing the transmitter to transmit a light pulse when the transmitter static LDC is set to a direction of transmissions.
7 . The active controller of claim 2 , wherein the light source is any one of: a laser, a light emitting diode (LED), and an array of LEDs.
8 . The active sensor of claim 2 , wherein the at least one transmitter lens is polarized at a first predefined angle.
9 . The active sensor of claim 8 , wherein the receiver further comprises:
a detector configured to detect light signals from at least one direction of the first plurality of directions;
a receiver static light directing circuit (LDC) configured to direct the light pulses emitted by the transmitter in a second plurality of directions; and
at least one receiver lens.
10 . The active sensor of claim 9 , wherein the receiver static LDC includes at least one microelectromechanical system (MEMS) mirror.
11 . The active sensor of claim 9 , wherein the receiver static LDC is any of: an acousto-optic modulator (AOM), and an electro-optic modulator (EOM).
12 . The active sensor of claim 9 , wherein the controller is further configured to cause the receiver static LDC to change between the second plurality of directions to match each of the respective first plurality of directions.
13 . The active sensor of claim 9 , wherein the detector is any one of: a photodiode, an array of photodiodes, a charge coupled device (CCD), and a complementary metal oxide semiconductor (CMOS) light sensor.
14 . The active sensor of claim 9 , wherein the at least one receiver lens is polarized at a second predefined angle, wherein the second predefined angle is the same as the first predefined angle.
15 . The active sensor of claim 1 , wherein the active measurements are performed when at least one of the active sensor, the passive sensor, and the target object is in motion.
16 . The active sensor of claim 15 , wherein the controller is configured to determine at least the direction of a transmitted light pulse respective of a new location of the at least one of the active sensor, the passive sensor, and the target object.
17 . The active sensor of claim 15 , wherein the controller is configured to determine the new location based on information from at least one motion sensor and based on a time elapsed between when the image was acquired by the passive sensor and until the transmission of the light pulse.
18 . The active sensor of claim 1 , wherein each target object is classified as any of: a non-stationary object, and a suspicious object.
19 . The active sensor of claim 1 , wherein the active sensor is coupled to the passive sensor.
21 . The active sensor of claim 1 , wherein the at least one transmitter and the at least one receiver are integrated in a single device.
22 . The active sensor of claim 1 , wherein the at least one transmitter and the at least one receiver are distributed.
23 . A method for controlling an active sensor to perform active measurements of a scene, comprising:
receiving an identification of at least one target object recognized in an image acquired by a passive sensor;
receiving a current location of the at least one target object;
determining an energy level, a direction, and a timing of a light pulse to be transmitted to each of the at least one target object;
setting a transmitter with the determined energy level, direction, and timing for emitting each light pulse;
setting a receiver to receive each light pulse reflected from the at least one target object at the determined at least one direction; and
measuring a distance to each of the at least one target object based on the corresponding emitted light pulse and the corresponding detected light pulse.
24 . The method of claim 23 , further comprising:
setting, for each determined direction, each transmitter static LDC and each receiver static LDC to the determined direction.
25 . The method of claim 23 , further comprising:
setting each transmitter to transmit a light pulse when the transmitter static LDC is set to the corresponding determined direction.
26 . The active sensor of claim 23 , wherein the active measurements are performed when at least one of the active sensor and the target objection is in motion.
27 . The active sensor of claim 24 , further comprising:
determining at least the direction of a transmitted light pulse based on a new location of at least one of the active sensor and the target object, wherein the new location is determined based on information from at least one motion sensor and based on a time elapsed from when the image was acquired by the passive sensor and until the transmission of the light pulse.