Object detection device and illumination system provided therewith
View Patent ↗An object detection device comprises an active sensor, an amplifying circuit configured to divide and amplify a sensor signal outputted from said active sensor with respect to each a plurality of frequency bands through each amplifier, and a determining unit determining the presence or absence of a detection target object by comparing an output of said amplifying circuit with a predetermined threshold value. A noise determining unit controls a switching circuit so as to turn off a switch inserted between said determining unit and an amplifier having a band pass including a noise of a particular frequency, when determining that the noise of the particular frequency is produced constantly by using an analysis result outputted from a frequency analyzer detecting intensity of each frequency of the sensor signal.
1. An object detection device comprising:
an active sensor configured to transmit a detection wave to a predetermined detection area, and to receive the detection wave reflected by a detection target object, and to thereby detect the presence or absence of the detection target object in the predetermined detection area, and to output a sensor signal;
a signal processor configured to divide the sensor signal outputted from said active sensor to sensor signals with respect to a plurality of frequency bands, and output the divided sensor signals;
a determining unit configured to determine the presence or absence of the detection target object by comparing the divided sensor signals outputted from said signal processor with a plurality of predetermined threshold values respectively,
the plurality of predetermined threshold values being defined with respect to the plurality of frequency bands, respectively;
a frequency analyzer configured to detect a signal intensity of individual frequencies of the sensor signal outputted from said active sensor spaced apart from each other in 1 [Hz] units; and
a noise rejection unit configured to cause said determining unit to invalidate, from among the plurality of frequency bands, a frequency band including a noise of a particular frequency having a certain signal intensity greater than or equal to a defined value, when the noise of the particular frequency is detected constantly from the signal intensity of the particular frequency outputted from said frequency analyzer.
2. The object detection device as claimed in claim 1 , wherein said signal processor comprises an amplifying circuit having a plurality of amplifiers, said plurality of amplifiers being configured to respectively amplify the divided sensor signals with respect to the plurality of frequency bands to output to said determining unit.
3. The object detection device as claimed in claim 1 , wherein said active sensor is a Doppler sensor using a radio wave as the detection wave,
wherein said Doppler sensor is configured to output the sensor signal having a frequency which is equivalent to a frequency difference between the detection wave transmitted to the detection area and the detection wave reflected by the detection target object moving in the detection area.
4. The object detection device as claimed in claim 3 , wherein the sensor signal outputted from said active sensor includes a predetermined frequency band which depends at least on a size of the detection target object and which has a width greater than or equal to a predetermined width, when said active sensor detects the presence of the detection target object,
wherein a band width of each of the plurality of frequency bands for the divided sensor signals outputted from said signal processor is defined to be narrower than a band width of the predetermined frequency band.
5. The object detection device as claimed in claim 1 wherein said determining unit is configured to redefine the plurality of predetermined threshold values according to the surrounding environment in stable state, where a variation width of the signal intensity of the sensor signal detected by said frequency analyzer is within a defined range during a predetermined time period.
6. An illumination system comprising:
the object detection device as claimed in claim 1 ; and
a lighting apparatus connected to the object detection device,
wherein the object detection device comprises a lighting controller, said lighting controller controlling a lighting state of said lighting apparatus to activate said lighting apparatus, when detecting the presence of the detection target object.
7. An illumination system comprising:
the object detection device as claimed in claim 2 ; and
a lighting apparatus connected to the object detection device,
wherein the object detection device comprises a lighting controller, said lighting controller controlling a lighting state of said lighting apparatus to activate said lighting apparatus, when detecting the presence of the detection target object.
8. An illumination system comprising:
the object detection device as claimed in claim 3 ; and
a lighting apparatus connected to the object detection device,
wherein the object detection device comprises a lighting controller, said lighting controller controlling a lighting state of said lighting apparatus to activate said lighting apparatus, when detecting the presence of the detection target object.
9. An illumination system comprising:
the object detection device as claimed in claim 4 ; and
a lighting apparatus connected to the object detection device,
wherein the object detection device comprises a lighting controller, said lighting controller controlling a lighting state of said lighting apparatus to activate said lighting apparatus, when detecting the presence of the detection target object.
10. An illumination system comprising:
the object detection device as claimed in claim 5 ; and
a lighting apparatus connected to the object detection device,
wherein the object detection device comprises a lighting controller, said lighting controller controlling a lighting state of said lighting apparatus to activate said lighting apparatus, when detecting the presence of the detection target object.