System and method for fusing data from a single pixel thermopile and a passive infrared sensor to count occupants in an open office

Abstract

A system for determining occupancy in an environment is provided. The system includes a plurality of sensor bundles, each bundle including a presence sensor and a motion sensor. The system further includes a controller in communication with each sensor bundle. The controller is configured to designate one of the sensor bundles as a presence trigger when a person is present within a field of view of the presence sensor. The controller is further configured to designate one of the sensor bundles as a motion trigger when a person is moving within a field of view of the motion sensor. The controller is further configured to determine trigger bundle counts for sensor bundles that are both presence triggers and motion triggers. The controller is further configured to determine an occupancy count for the environment based on the trigger bundle counts.

Description

Technical Field

[0001] The present disclosure generally relates to counting occupants in an environment such as an open office.

Background Art

[0002] Modern open office environments typically include multiple smart lighting fixtures that are electrically connected via a connected lighting system. These smart lighting fixtures often include various sensors for collecting data from the open office environment. By using the information collected from various different sensors, various characteristics of the open office can be determined. One such important characteristic is office occupancy.

[0003] An example of a sensor that can be used in a connected lighting system is a single-pixel thermopile (SPT). The SPT uses a thermocouple to measure the temperature within its field of view. A thermocouple consists of two dissimilar conductors, a hot weld, and a cold weld. A temperature difference across the thermocouple generates a voltage. The cold weld of the thermocouple is insulated and measures only the case temperature of the SPT. The hot weld is exposed to the field of view and absorbs the heat emitted by a person within the field of view. The temperature of an object within the field of view is reported by the sensor as the object temperature T o and the case temperature is also reported by the sensor as the ambient temperature T a . However, a one-dimensional T o measurement typically does not contain sufficient data to determine an accurate count of the occupants.

[0004] A second example of a sensor that can be used in a connected lighting system is a Passive Infrared (PIR) sensor. PIR can be used to report both the binary occupancy (occupied or unoccupied) of a room and the type of movement seen within its field of view. Specifically, minor motion, medium motion, and major motion can be reported. When a luminaire equipped with PIR is installed and commissioned in an office environment, the PIR generates a count of events corresponding to minor motion, medium motion, major motion, and no motion. The motion count is generated according to a sampling rate based on the networking connection of the lighting system.

[0005] US 2019303661 A1 discloses a system including a first detector for detecting whether a multi-occupancy space is occupied by at least one individual and a plurality of second detectors for detecting whether an individual is present in each of a plurality of respective spaces within the multi-occupancy space. The controller is configured to monitor whether an individual is present in the multi-occupancy space based on a signal derived from the first detector. If the presence of at least one individual is detected based on the signal derived from the first detector, the controller determines the occupancy of the multi-occupancy space based on signals derived from the plurality of second detectors. Summary of the Invention Problems to be Solved by the Invention

[0006] The present disclosure relates to an inventive system and method for counting occupants in an environment such as an open office. The system and method analyze data collected by presence sensors such as single pixel thermopiles (SPTs) and motion sensors such as passive infrared (PIR) sensors. Fusing the data collected by the presence sensor and the motion sensor provides more accurate occupancy counting.

Means for Solving the Problems

[0007] Generally, in one aspect, a system for determining occupancy in an environment is provided. The system may include a plurality of sensor bundles. Each sensor bundle may include a presence sensor. The presence sensor may be configured to generate a presence signal. The presence sensor may be an SPT.

[0008] Each sensor bundle may include a motion sensor. The motion sensor may be configured to generate a motion signal. The motion sensor may be a PIR sensor.

[0009] The system may further include a controller. The controller may communicate with each sensor bundle. The controller may be configured to designate one of the sensor bundles as presence triggered based on the presence signal and a presence detector when one or more people are present within the field of view of the presence sensor of the sensor bundle.

[0010] The presence detector may include a step analysis module to determine whether one or more people are present within the field of view of the presence sensor. The step analysis module may be configured to generate a convolution presence signal by convolving a presence signal and a step function. The presence detector may further be configured to analyze the convolution presence signal for one or more peaks. The peaks may correspond to one or more people being present within the field of view of the presence sensor. Further, the designation of a sensor bundle as a presence trigger may be based on the peaks of the convolution presence signal.

[0011] The controller may further be configured to designate one of the sensor bundles as a motion trigger based on a motion signal and a motion detector when one or more people are moving within the field of view of the motion sensor of the sensor bundle. The motion detector may include a motion threshold. The motion detector may include an analysis period.

[0012] The controller may further be configured to determine a triggered bundle count of a sensor bundle that is both a presence trigger and a motion trigger.

[0013] The controller may further be configured to determine an occupancy count of the environment based on the triggered bundle count. Further, the occupancy count may be based on an occupancy count module. The occupancy count module may be configured to correlate one or more triggered bundle counts with one or more occupancy counts.

[0014] Generally, in one aspect, a method for determining occupancy in an environment is provided. The method may include generating a plurality of presence signals. Each presence signal may correspond to one presence sensor of a plurality of sensor bundles.

[0015] The method may further include generating a plurality of motion signals. Each motion signal may correspond to one motion sensor of a plurality of sensor bundles.

[0016] The method may further include, via a controller, designating, as a presence trigger, one of the sensor bundles based on the presence signal and a presence detector when one or more people are within the field of view of the presence sensor of the sensor bundle.

[0017] The method may further include generating a convolved presence signal by convolving the presence signal and a step function.

[0018] The method may further include, via a controller, analyzing the convolved presence signal for one or more peaks, where the peaks may correspond to one or more people being within the field of view of the presence sensor. Further, designating the sensor bundle as a presence trigger may be based on the peaks of the convolved presence signal.

[0019] The method may further include, via a controller, designating, as a motion trigger, one of the sensor bundles based on the motion signal and a motion detector when one or more people are moving within the field of view of the motion sensor of the sensor bundle. The motion detector may include a motion threshold. The motion detector may include an analysis period.

[0020] The method may further include, via a controller, determining a trigger bundle count of the sensor bundle that is both a presence trigger and a motion trigger.

[0021] The method may further include determining an occupancy count of the environment based on the trigger bundle count via a controller. Further, the occupancy count may be based on correlating one or more trigger bundle counts with one or more occupancy counts via an occupancy count module.

[0022] In various implementations, a processor or controller may be associated with one or more storage media (collectively referred to herein as “memory,” such as volatile and non-volatile computer memories like RAM, PROM, EPROM, and EEPROM, floppy disks, compact disks, optical disks, magnetic tapes, etc.). In some implementations, these storage media may be encoded with one or more programs that, when executed on one or more processors and / or controllers, perform at least some of the functions discussed herein. The various storage media may be fixed within the processor or controller, or may be portable such that one or more programs stored thereon can be loaded into the processor or controller to implement the various aspects discussed herein. The term “program” or “computer program” is used herein in a general sense to refer to any type of computer code (e.g., software or microcode) that can be employed to program one or more processors or controllers.

[0023] It should be understood that all combinations of the above-described concepts and additional concepts discussed in more detail below (subject to the condition that such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of the claimed subject matter recited at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should also be understood that any terms explicitly employed herein that may also appear in any incorporated by reference disclosure should be given a meaning that most closely matches the particular concepts disclosed herein.

[0024] These and other aspects of the various embodiments will become apparent and be elucidated with reference to the embodiments described below.

Brief Description of the Drawings

[0025] In the drawings, like reference characters generally refer to the same parts throughout different figures. Also, the drawings are not necessarily to scale; instead, generally, emphasis is placed on illustrating the principles of the various embodiments.

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Modes for Carrying Out the Invention

[0026] The present disclosure relates to an inventive system and method for counting occupants in an environment such as an open office. The system and method analyze data collected by presence sensors such as single pixel thermopiles (SPTs) and motion sensors such as passive infrared (PIR) sensors, each included in a sensor bundle of a connected lighting system. Analyzing data collected by two or more different types of sensors provides more accurate occupancy counting, especially when an occupant is sitting relatively still for a long time. In the case of an SPT, the pause time of the PIR sensor is used to determine the baseline of the SPT. This baseline corresponds to the SPT having an unoccupied field of view. The data collected by the SPT may be analyzed using step analysis to determine the presence (or absence) of one or more people in the field of view of each SPT. Additionally, the data collected by the PIR sensor may be analyzed to determine whether a person is moving in the field of view of each PIR. The system then sums the number of sensor bundles in which the sensors are detecting both presence and motion and correlates this sum with an estimated occupancy count value.

[0027] Referring to FIGS. 1 and 2, in one aspect, a system 100 for determining occupancy in an environment 110 is provided. The environment 110 may be an indoor or outdoor area where it is advantageous to determine occupancy. In one example, the environment 110 may be an individual office within an office building. The system 100 may be electrically connected to a lighting system for the environment 110. The lighting system may respond to the occupancy of the environment 110. In one example, the lighting system may dim or deactivate one or more lighting fixtures in the case of low occupancy. In another example, the lighting system may brighten or activate one or more lighting fixtures in the case of high occupancy.

[0028] System 100 may include a plurality of sensor bundles 120. The sensor bundles 120 may be installed in conjunction with an illumination system. In such an example, one or more sensor bundles 120 may be attached to the housing of one or more luminaires of the illumination system.

[0029] Each sensor bundle 120 may include a presence sensor 130. The presence sensor 130 may be configured to generate a presence signal 160. The presence signal 160 may be an electronic representation of the presence of one or more persons 180 within the field of view 190 of the presence sensor 130. The presence sensor 130 may be an SPT. The SPT generates the presence signal 160 in terms of temperature. Exemplary presence signals 160 captured by the SPT are shown in FIGS. 3A and 3B. In these exemplary signals, the measured temperature significantly increases, i.e., “steps up,” with the presence of one or more persons 180. In other examples, the presence sensor 130 may be any sensor or plurality of sensors (passive or active) capable of detecting presence. In one example, the presence sensor 130 is positioned within an office to detect the presence of one or more persons 180 within the office as part of the sensor bundle 120. The sensor bundle 120 may be configured to transmit the presence signal 160.

[0030] Each sensor bundle 120 may include a motion sensor 140. The motion sensor 140 may be configured to generate a motion signal 170. The motion signal 170 may be an electronic representation of the movement of one or more persons 180 within the field of view 200 of the motion sensor 140. The motion sensor 140 may be a PIR sensor. In other examples, the motion sensor 140 may be any sensor or sensors (passive or active) capable of detecting motion. In one example, the motion sensor 140 is positioned within an office to detect the motion of one or more persons 180 within the office. The motion signal 170 may include data that designates each detected motion as a "small", "medium", or "large" movement. The sensor bundle 120 may be configured to transmit the motion signal 170.

[0031] System 100 may further include a controller 150. The controller 150 may include a memory 350 and a processor. The controller 150 may communicate with each sensor bundle 120. The communication may be wired and / or wireless, depending on the application. The controller 150 may be configured to receive the presence signal 160 transmitted by the sensor bundle 120. Similarly, the controller may be configured to receive the motion signal 170 transmitted by the sensor bundle 120.

[0032] The controller 150 may be configured to designate, as a presence trigger, one of the sensor bundles 120 based on the presence signal 160 and the presence detector 210 when one or more persons 180 are present within the field of view 190 of the presence sensor 130 of the sensor bundle 120. The presence detector 210 includes criteria, such as algorithms and variables, that are used by the controller 150 to analyze the presence signal 160. In one example, the controller 150 may analyze the presence signal 160 for criteria defined by the presence detector 210 indicating the presence of one or more persons 180 and thus an occupied field of view 190. Similarly, the controller 150 may be configured to remove the presence triggered designation of the sensor bundle 120 based on the presence signal 160 and the presence detector 210 when one or more persons 180 are no longer present within the field of view 190 of the presence sensor 130.

[0033] The presence detector 210 may include a step analysis module 280 to determine whether one or more persons 180 are present in the field of view 190 of the presence sensor 130. The step analysis module 280 may be configured to analyze the presence signal 160 for one or more “step-ups” and “step-downs” in temperature. A “step-up” in temperature is likely to indicate that a person 180 is entering the field of view 190 of the presence sensor 130, while a “step-down” is likely to indicate that a person 180 is leaving. Exemplary presence signals 160 are shown in FIGS. 3A and 3B. In these exemplary signals, the measured temperature increases significantly, i.e., “steps up,” when one or more persons 180 are in the field of view of the presence sensor 160.

[0034] Referring to FIGS. 3C and 3D, the step analysis module 280 may be configured to generate a convolution presence signal 290 by convolving the presence signal 160 and the step function 300. The convolution presence signal 290 is shown in FIG. 3D. The presence detector 210 may further be configured to analyze the convolution presence signal 290 for one or more peaks 310. The peak 310 may correspond to the presence of one or more persons 180 within the field of view 190 of the presence sensor 130. As shown in FIGS. 3C and 3D, the convolution presence signal 290 peaks when the shape of the presence signal 160 corresponds to the step function 300. More specifically, the convolution presence signal 290 peaks (or crests) to a maximum value during a “step up” and drops (or troughs) to a minimum value during a “step down”. By further processing the convolution presence signal 290 for peak 310 detection, the controller 150 may determine whether a “step up” or “step down” has occurred, and then further determine whether a person 180 has entered or exited the field of view 190 of the presence sensor 130. Further, the designation of the sensor bundle 120 as a presence trigger may be based on the peak 310 of the convolution presence signal 290.

[0035] The controller 150 may further be configured to designate one of the sensor bundles 120 as a motion trigger based on the motion signal 170 and the motion detector 220 when one or more persons 180 are moving within the field of view 200 of the motion sensor 140 of the sensor bundle 120. The motion detector 220 includes criteria such as algorithms and variables used by the controller 150 to analyze the motion signal 170. Similarly, the controller 150 may be configured to remove the motion triggered designation of the sensor bundle 120 based on the motion signal 170 and the motion detector 220 when one or more persons 180 are no longer moving within the field of view 200 of the motion sensor 140.

[0036] In one example, the controller 150 may analyze the motion signal 170 with respect to a criterion defined by a motion detector 220 that indicates the motion of one or more persons 180 and, thus, the occupied field of view 200 of the motion sensor 140.

[0037] The motion detector 220 may include a motion threshold 260. In one example, if the amplitude of the motion signal 170 exceeds the motion threshold 260, the field of view 200 of the motion sensor 140 is presumed to be occupied by one or more persons 180. If the amplitude of the motion signal 170 does not exceed the motion threshold 260, the field of view 200 is presumed to be unoccupied. The motion threshold 260 may be optimized according to the field of view 200 and / or the environment 110.

[0038] The motion detector 220 may include an analysis period 270. The analysis period 270 is the length of time for which the controller 150 analyzes the motion signal 170 to determine whether one or more persons 180 are moving within the field of view 200 of the motion sensor 140. In one example, if the motion signal 170 does not exceed the motion threshold 260 during the analysis period 270, the controller 150 may determine that the field of view 200 is unoccupied.

[0039] The motion detector 220 may include any other algorithm, value, or variable useful for analyzing the motion signal 170 for human motion.

[0040] The controller 150 may further be configured to determine a trigger bundle count 230 of the sensor bundle 120 that is both a presence trigger and a motion trigger. In one example, the trigger bundle count 230 is the sum of the sensor bundles 120 within the environment 110 that are both a presence trigger and a motion trigger. In other examples, certain sensor bundles 120 may be excluded from the trigger bundle count 230 for various reasons, such as environmental conditions or the placement of the sensor bundle 120. In one example, the motion signal may be used to correct the presence sensor data, such as the convolution presence signal 290 for one or more peaks 310, and the motion signal is analyzed for motion in the field of view within the environment. When the motion sensor also senses motion, the peak may correspond to the presence of one or more persons 180 within the field of view 190 of the presence sensor (130).

[0041] The controller 150 may further be configured to determine an occupancy count 240 of the environment 110 based on the trigger bundle count 230. Further, the occupancy count 240 may be based on an occupancy count module 250. The occupancy count module 250 may be configured to correlate one or more trigger bundle counts 230 with one or more occupancy counts 240. The correlation between the trigger bundle count 230 and the occupancy count 240 will typically be a direct relationship where the occupancy count 240 increases with an increase in the trigger bundle count 230. Further, the correlation will likely depend on the placement of the sensor bundles 120 in the environment. In one example, the occupancy count module 250 may correlate the trigger bundle counts 230 of three sensor bundles 120 with the occupancy count of four persons 180. The correlation used by the occupancy count module 250 may be determined via computer simulation, historical data, or a combination thereof.

[0042] Generally, in one aspect, a method 500 for determining occupancy in an environment is provided. The method may include generating 510 a plurality of presence signals. Each presence signal may correspond to one presence sensor of a plurality of sensor bundles.

[0043] The method may further include generating 520 a plurality of motion signals. Each motion signal may correspond to one motion sensor of a plurality of sensor bundles.

[0044] The method may further include, via a controller, designating 530 one of the sensor bundles as a presence trigger, based on the presence signal and a presence detector, when one or more people are present within the field of view of the presence sensor of the sensor bundle.

[0045] The method may further include generating 580 a convolved presence signal by convolving, via a controller, the presence signal and a step function.

[0046] The method may further include, via a controller, analyzing 590 the convolved presence signal for one or more peaks, which may correspond to one or more people being present in the field of view of the presence sensor. Further, designating 530 the sensor bundle as a presence trigger may be based on the peaks of the convolved presence signal.

[0047] The method may further include, via a controller, designating 540 one of the sensor bundles as a motion trigger, based on the motion signal and a motion detector, when one or more people are moving within the field of view of the motion sensor of the sensor bundle. The motion detector may include a motion threshold. The motion detector may include an analysis period.

[0048] The method may further include, via a controller, determining 550 a trigger bundle count of the sensor bundle that is both a presence trigger and a motion trigger.

[0049] The method may further include determining an occupancy count of the environment based on a trigger bundle count via a controller. Further, the occupancy count may be based on correlating one or more trigger bundle counts with one or more occupancy counts via an occupancy count module.

[0050] All definitions, as defined and used herein, are to be understood to govern the dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0051] The indefinite articles "a" and "an", as used in this specification and the claims, should be understood to mean "at least one" unless clearly indicated otherwise.

[0052] The phrase "and / or", as used in this specification and the claims, should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are present conjunctively in some cases and disjunctively in other cases. Multiple elements listed with "and / or" should be construed in the same manner, i.e., as "one or more" of the elements so conjoined. Other elements not specifically identified by the "and / or" clause may optionally exist, whether or not they are related to those specifically identified elements.

[0053] As used in this specification and the claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" is to be construed as inclusive, i.e., including at least one, but also including, optionally, additional items not enumerated among several elements or a list of elements, including two or more of them. Only terms such as "only one of", "exactly one of", or "consisting of" when used in the claims, where the contrary is clearly indicated, refer to including exactly one of several elements or a list of elements. Generally, the term "or" when used in this specification is to be construed as indicating an exclusive alternative (i.e., "one or the other, but not both") only when preceding an exclusive term such as "any of", "one of", "only one of", or "exactly one of".

[0054] As used in this specification and the claims, the phrase "at least one" referring to a list of one or more elements means at least one selected from any one or more of the elements in the list of those elements, but not necessarily including at least one of each of the specifically enumerated elements in the list of those elements, and it should be understood that it does not exclude any combination of the elements in the list of those elements. This definition also allows for the possibility that elements other than those specifically identified in the list of elements referred to by the phrase "at least one" may optionally be present, whether or not they are related to those specifically identified elements.

[0055] Also, unless clearly indicated otherwise, in any method claimed in this specification that includes two or more steps or acts, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are enumerated.

[0056] In both the claims and the above specification, all transitional phrases such as "comprising", "including", "carrying", "having", "containing", "involving", "holding", "consisting of", etc. should be understood as non-limiting, i.e., meaning including but not limited to. Only transitional phrases such as "consisting of" and "essentially consisting of" are closed or semi-closed transitional phrases, respectively.

[0057] Although several embodiments of the invention have been described and illustrated herein, those skilled in the art will readily conceive of various other means and / or structures for performing the functions described herein and / or for obtaining one or more of the results and / or advantages thereof, and such variations and / or modifications are considered to be within the scope of the embodiments of the invention described herein. More generally, all parameters, dimensions, materials, and configurations described herein are intended to be illustrative, and those skilled in the art will readily understand that the actual parameters, dimensions, materials, and / or configurations will vary depending on the particular application for which the teachings of the invention are used. Those skilled in the art will be able to recognize or confirm many equivalents to the specific embodiments of the invention described herein using only routine experimentation. Therefore, it should be understood that the above embodiments are presented by way of example only, and that embodiments of the invention other than those specifically described and claimed may be practiced within the scope of the appended claims and their equivalents. The embodiments of the invention disclosed herein are directed to each individual feature, system, article, material, kit, and / or method described herein. Furthermore, any combination of two or more such features, systems, articles, materials, kits, and / or methods is included within the scope of the invention disclosed herein, provided such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent.

Claims

1. A system for determining occupancy in an environment, comprising: A plurality of sensor bundles, each sensor bundle comprising: An occupancy sensor configured to generate an occupancy signal; and A motion sensor configured to generate a motion signal; A plurality of sensor bundles; A controller in communication with each sensor bundle, the controller being configured to: Designate one of the sensor bundles as an occupancy trigger based on the occupancy signal and an occupancy detector, when one or more people are within the field of view of the occupancy sensor of the sensor bundle, the occupancy detector including criteria used by the controller to analyze the occupancy signal indicative of the presence of one or more people; Designate one of the sensor bundles as a motion trigger based on the motion signal and a motion detector, when one or more people are moving within the field of view of the motion sensor of the sensor bundle, the motion detector including criteria used by the controller to analyze the motion signal indicative of the motion of one or more people; Determine a trigger bundle count for the sensor bundle that is both an occupancy trigger and a motion trigger; and Determine the occupancy count of the environment based on correlating one or more trigger bundle counts to one or more occupancy counts via an occupancy count module; A controller configured as such; and A system comprising the same.

2. The system of claim 1, wherein the motion detector includes a motion threshold.

3. The system of claim 1, wherein the motion detector includes an analysis period, the analysis period being the length of time for which the controller analyzes the motion signal to determine whether one or more people are moving within the field of view of the motion sensor.

4. The system of claim 1, wherein the motion sensor is a passive infrared sensor.

5. The system of claim 1, wherein the occupancy sensor is a single pixel thermopile.

6. A method for determining occupancy in an environment, comprising: Generating a plurality of occupancy signals, each occupancy signal corresponding to an occupancy sensor of one of a plurality of sensor bundles; Generating a plurality of motion signals, each motion signal corresponding to one motion sensor of the plurality of sensor bundles, Via a controller, designating, as a presence trigger, one of the sensor bundles based on the presence signal and a presence detector when one or more people are within the field of view of the presence sensor of the sensor bundle, the presence detector including criteria used by the controller to analyze the presence signal indicating the presence of one or more people, Via the controller, designating, as a motion trigger, one of the sensor bundles based on the motion signal and a motion detector when one or more people are moving within the field of view of the motion sensor of the sensor bundle, the motion detector including criteria used by the controller to analyze the motion signal indicating the motion of one or more people, Determining, via the controller, a trigger bundle count of a sensor bundle that is both a presence trigger and a motion trigger, Determining, via the controller, an occupancy count of the environment based on correlating one or more trigger bundle counts with one or more occupancy counts via an occupancy count module, A method comprising.

7. The method according to claim 6, wherein the motion detector includes a motion threshold.

8. The method according to claim 6, wherein the motion detector includes an analysis period, and the analysis period is a length of time for the controller to analyze the motion signal to determine whether one or more people are moving within the field of view of the motion sensor.

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