Abstract:
A recognition system for a bathroom fixture operates by sending a photon pulse from an emitter, monitoring for a presence of an object within a predefined detection zone, and operating the bathroom fixture if the distance of the object is within the predefined detection zone. The monitoring occurs by detecting photons with a sensor, establishing a correlated or uncorrelated state of the detected photons, optically filtering the detected photons, calculating a distance of the object from the sensor based on the photon pulse sent from the emitter and the returned photons collected at the sensor, and determining whether the distance of the object from the sensor falls within the predefined detection zone.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 62/206,036 filed Aug. 17, 2015, the contents of which are incorporated by reference herein in their entirety for all purposes. 
     
    
     TECHNICAL FIELD 
       [0002]    This disclosure relates to recognition systems for bathroom fixtures. In particular, this disclosure relates to recognition systems for the accurate detection of an object within a pre-determined distance from a sensor for the purpose of selectively operating the fixture. 
       BACKGROUND 
       [0003]    Infrared sensors have been used for detection or recognition systems in automated bathroom fixtures such as sink faucets, soap dispensers, and towel dispensers. Infrared sensors are active sensors that utilize low power detection and rely on the reflective properties of intended targets to accurately detect the presence of an object (for example, a user&#39;s hand). 
         [0004]    Typical infrared sensors suffer from at least three primary drawbacks. First, the detection zone is defined by the entire line-of-sight of the sensor leading to a loosely defined detection zone. For example, a typical infrared sensor used in a sink installation may detect a dirty sink surface as a false positive resulting in undesirable functionality. This line-of-sight detection zone can lead to missed users and false detections. Second, detection is highly dependent on the reflective properties of a target object. The infrared sensor will react differently to varying colors and textures leading to inconsistent or undesirable operation. Finally, ambient light can heavily affect the performance of typical infrared sensors. In order to overcome inconsistencies introduced by lighting, systems are tuned individually to achieve desirable performance, and may require initial or periodic calibration. This leads to increased installation costs and installer dependence, leading to inconsistency of operation. 
         [0005]    Therefore, a recognition system and corresponding method of operation compatible with bathroom fixtures is needed possessing improved functionality. 
       SUMMARY OF THE INVENTION 
       [0006]    The foregoing needs are met by the methods, apparatus, and/or systems for recognizing and responding to the presence of a target object according to the disclosure. 
         [0007]    According to one aspect, a method of operating a recognition system for a bathroom fixture is disclosed. The method includes sending a photon pulse from an emitter, monitoring for a presence of an object within a predefined detection zone, and operating the bathroom fixture if the distance of the object from the sensor is within the predefined detection zone. The step of monitoring for the presence of an object within a predefined detection zone includes detecting photons with a sensor in which the detected photons include returned photons from the photon pulse sent from the emitter that have reflected off of the object, establishing a correlated state or an uncorrelated state of the detected photons, optically filtering the detected photons, calculating a distance of the object from the sensor based on the photon pulse sent from the emitter and the returned photons collected at the sensor, and determining whether the distance of the object from the sensor falls within the predefined detection zone. 
         [0008]    In some forms, the predefined detection zone may be selected from set amounts, distances, or percentages of traveled distance of the photons. More specifically, the predefined detection zone may be within the range of one inch from the sensor to two inches from a fixed opposite surface, such that a false photon detection from the fixed opposite surface is avoided. 
         [0009]    Calibration of the predefined detection zone may occur before the sensor begins to monitor. The controller may further be set to periodically re-calibrate to the predefined detection zone. 
         [0010]    The distance calculated may be a result of the time lapse between the sending the photon pulse and detecting the returned photons (i.e., the distance may be determined by multiplying the speed of the photon by the time lapse between emission and reception of the photon). Furthermore, to ensure positive detection of an object, the step of sending a photon pulse may comprise sending a plurality of photon pulses for use in establishing the correlated state or the uncorrelated state of the detected photons. 
         [0011]    In some forms, the sensor may include an array of Single Photon Avalanche Diode (SPAD) detectors. 
         [0012]    To improve detection and accuracy, the emitted and detected photons may be clustered around a wavelength outside of the visible light spectrum. Specifically, the visible light spectrum is defined by wavelengths between 390 nanometers to 700 nanometers. In certain situations, it may be considered advantageous to have the photons clustered around a wavelength of 850 nanometers. 
         [0013]    As it is established whether the detected photons are in the correlated state or the uncorrelated state, the correlation (or lack thereof) may be used to establish how the method proceeds. For example, if the detected photons are in the correlated state, then optical filtering may be executed. Whereas if the detected photons are in the uncorrelated state, the emitter may continue to send photon pulses. In regards to optically filtering the photons, this may include determining if the detected photons are ambient (potentially based on information also detected from an ambient light sensor) and continuing to send photon pulses if the detected photons are indeed primarily ambient so as to avoid a false positive detection of an object in the pre-defined zone. Additionally, the step of optically filtering the detected photons may result in a lowering of the system noise. 
         [0014]    According to one aspect, an automatically controlled water valve system is disclosed. The automatically controlled water valve system includes a water valve, an actuator, a time-of-flight sensor, and a controller. The water valve is moveable between an open position and a closed position. When the valve is in the open position water flow is provided, and in the closed position water flow is inhibited. The actuator is coupled to the water valve to move the water valve between the open position and the closed position. The time-of-flight sensor is arranged to send and receive photon pulses. The controller is in communication with the actuator and the time-of-flight sensor and defines a detection zone for the time-of-flight sensor. The controller is configured to establish a correlated state or an uncorrelated state of the photons that are received by the time-of-flight sensor, is configured to optically filter the photon pulses that are received by the time-of-flight sensor, and activates the actuator in response to signals from the time-of-flight sensor indicating that a target object is within the detection zone. 
         [0015]    When the water valve is in the open position, the controller may monitor the defined detection zone. In such a case, the controller may be configured to deactivate the actuator in response to the signals from the time-of-flight sensor (for example, if a hand of a user is removed from the predefined detection zone). 
         [0016]    The time-of-flight sensor may specifically utilize an array of Single Photon Avalanche Diode detectors. 
         [0017]    In some forms, the time-of-flight sensor may be positioned outside a bathroom fixture or within a bathroom fixture. For example, the time-of flight sensor may be placed at the head of a faucet, just above and outward the position of the aerator. In other examples, the time-of-flight sensor may be placed on a radially outward facing surface of a faucet such as along the “goose-neck” of the faucet body. Still yet the sensor could be mounted in or on a surface that is not the fixture itself such as, for example, on a portion of the sink. 
         [0018]    According to another aspect, a recognition system for a bathroom fixture is disclosed. The recognition system includes a time-of-flight sensor and a controller. The time-of-flight sensor is configured to send and receive photon pulses and to send a distance signal. The controller receives the distance signal and triggers an operation if the distance signal falls within a detection zone. 
         [0019]    In some forms, the controller may utilize an ambient light sensor to detect and account for the ambient light conditions in view of the time-of-flight sensor. The ambient light sensor may result in a reduction in system noise. 
         [0020]    Prior to the recognition system beginning to monitor, the system may be calibrated to the desired detection zone. 
         [0021]    This method, automatically controlled water valve system, and recognition system may be used in a number of bathroom fixtures including, but not limited to, faucets, soap and other fluid dispensers, toilets, doors, and paper towel dispensers. 
         [0022]    These and other aspects of the invention will become apparent from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown embodiments of the invention. Such embodiments do not necessarily represent the full scope of the invention and reference is made therefore, to the claims herein for interpreting the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The present disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. 
           [0024]      FIG. 1  is a schematic representation of one exemplary embodiment of a recognition system. 
           [0025]      FIG. 2  is a front view of a time-of-flight sensor of the recognition system shown in  FIG. 1 . 
           [0026]      FIG. 3  is a right side view of the time-of-flight sensor of  FIG. 2 . 
           [0027]      FIG. 4  is a rear view of the time-of-flight sensor of  FIG. 2 . 
           [0028]      FIG. 5  is a diagram illustrating a principal of operation of the time-of-flight sensor of  FIG. 2 . 
           [0029]      FIG. 6  is a diagram illustrating how photon pulses of the time-of-flight sensor of  FIG. 2  are correlated. 
           [0030]      FIG. 7  is a chart showing the wavelengths of various detected photons in which the detected wavelengths are clustered around 850 nanometers. 
           [0031]      FIG. 8  is a chart showing convergence time for the recognition system versus actual or target ranges for objects of varying reflectance. 
           [0032]      FIG. 9  is a flow chart representing a method of operating the recognition system shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0033]    Before the present invention is described in further detail, it is to be understood that the invention is not limited to the particular aspects described. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to be limiting. The scope of the present invention will be limited only by the claims. As used herein, the singular forms “a”, “an”, and “the” include plural aspects unless the context clearly dictates otherwise. 
         [0034]    It should be apparent to those skilled in the art that many additional modifications beside those already described are possible without departing from the inventive concepts. In interpreting this disclosure, all terms should be interpreted in the broadest possible manner consistent with the context. Variations of the term “comprising”, “including”, or “having” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, so the referenced elements, components, or steps may be combined with other elements, components, or steps that are not expressly referenced. Aspects referenced as “comprising”, “including”, or “having” certain elements are also contemplated as “consisting essentially of” and “consisting of” those elements, unless the context clearly dictates otherwise. It should be appreciated that aspects of the disclosure that are described with respect to a system are applicable to the methods, and vice versa, unless the context explicitly dictates otherwise. 
         [0035]    Numeric ranges disclosed herein are inclusive of their endpoints. For example, a numeric range of between 1 and 10 includes the values 1 and 10. When a series of numeric ranges are disclosed for a given value, the present disclosure expressly contemplates ranges including all combinations of the upper and lower bounds of those ranges. For example, a numeric range of between 1 and 10 or between 2 and 9 is intended to include the numeric ranges of between 1 and 9 and between 2 and 10. 
         [0036]      FIG. 1  shows an exemplary bathroom fixture in the form of a sink  14  that includes an automated faucet  18  installed therein. In other embodiments, the bathroom fixture may be a toilet, urinal, soap dispenser, towel dispenser, door, toilet paper dispenser, or another fixture/appliance, as desired. Those skilled in the art will recognize that aspects of the below disclosure and the claims can apply to fixtures other than sinks and may indeed include fixtures outside a bathroom. 
         [0037]    The automated faucet  18  includes a recognition system  20  that includes a time-of-flight sensor  22  in communication with a controller  26  (schematically indicated in  FIG. 1 ) that provides commands to an actuator in the form of a water valve  30 . The time-of-flight sensor  22  is shown in detail in  FIGS. 2-4  and includes a light emitter  34 , an ambient light sensor  38 , and a sensor  42 . As will be described in more detail below, the light emitter  34  emits photons that the sensor  42  detects photons (returned photons from the light emitter and/or ambient photons). The ambient light sensor  38  is able to automatically detect and account for the ambient lighting in view of the time-of-flight sensor  22 . 
         [0038]    The time-of-flight sensor  22  includes an onboard sensor controller  46  that processes the raw signals from the light emitter  34 , the ambient light sensor  38 , and the sensor  42  and communicates with the controller  26  via the twelve connections  50  located on the rear of the time-of-flight sensor  22 . In one exemplary embodiment, the time-of-flight sensor  22  is a model VL6180X 3-in-1 proximity sensor offered by STMicroelectronics of Geneva, Switzerland. 
         [0039]      FIGS. 5 and 6  show how pulses of photons  36  are emitted from the light emitter  34 , reflect off an object  54  (for example, the hands of a user), return along a path  37  and are detected by the sensor  42 . As shown in  FIG. 6 , the sensor controller  46  is able to correlate emitted photons from detected ambient photons. The emitted photon pulse  21  is shown is the top line with the detected photon pulse  23  being illustrated on the lower line. The emitted photon pulse  21  is comprised of photons  27  that are later detected by the sensor  42  with intervening delay  28 . The detected photon pulse  23  is potentially comprised of both the returned, correlated photons  27  and ambient, uncorrelated photons  25 . The sensor controller  46  records the time lapse or delay  28  between sending the photon pulse along and detecting the photons. A calculation is completed to determine a distance between the time-of-flight sensor  22  and the target object  54 . Effectively, the measured distance is equal to the photon travel time multiplied by the speed of light. Because the speed of light is extremely fast in comparison to the speed of the detection methods, in calculating distance, it may be the case that many repeated, timed pulses are used to establish correlation and some offset is factored in based on the limitations of into the time-of-flight sensor  22 . 
         [0040]      FIGS. 7-8  illustrate how the time-of-flight sensor  22  responds well to target objects  54  of varying reflectance and provides a very fast response. The ambient light sensor  38  and the sensor controller  46  allow for optical filtering as shown in  FIG. 7 . In  FIG. 7 , the detected photons are correlated and clustered around the  850  nanometer wavelength, a value outside the visible light spectrum. This reduces the impact of ambient, uncorrelated photons and lowers system noise. One notable effect of this optical filtering is that the recognition system  20  does not report false distance and therefore false positives in high ambient light conditions. Photopic light  2  is shown with photon pulses clustered around 850 nanometers. Photon pulse  14  shows a 0 degree shift, photon pulse  10  shows a 5 degree shift, photon pulse  12  shows a 10 degree shift, photon pulse  6  shows a 15 degree shift, photon pulse  8  shows a 30 degree shift, and photon pulse  4  shows a 50 degree shift.  FIG. 8  shows that convergence time, while different for various reflectivities of the object being detected, is not highly dependent on how reflective a target object is (i.e., the convergence time is relatively small—under 30 ms for distances of up to 160 mm). Thus, the range of conversion times can be used to turn the sensor off if an object is not detected within a certain amount of time (i.e., correlation does not occur). Turning the sensor off after this period of time can save power. 
         [0041]    Note that by observation it has been found that the reflectance of the target object does not result in a significantly different calculated target distance and a generally linear dependence between the two independent of the reflectance of the object. 
         [0042]    Setup and operation of the exemplary recognition system  20  will be described below with reference to  FIG. 9 . When the recognition system  20  is installed onto the sink  14 , a detection zone  58  is defined within the controller  26 .  FIG. 1  shows a representation of the detection zone  58  wherein the sink  14  does not enter into the detections zone  58  such that a false positive from the sink  14  surface is not possible. 
         [0043]    With reference to  FIG. 9 , the sink  14  and the recognition system  20  are installed at step  62 . After installation, the detection zone  58  is set in the controller  26  at step  66 . The controller  26  may be programmed to set the detection zone to be a certain distance from the sensor  22  and opposite surface (i.e., bowl surface of the sink). For example, after initial installation, the limits of sensing range may be automatically calibrated to be one inch from the sensor and two inches from opposite end of the sink (or other pre-determined or set amounts, distances, or percentages of traveled distance of the photons). The controller  26  may also be set to periodically re-calibrate to ensure maintained accuracy of the system. Alternatively, the detection zone  58  may be preset based on the product (e.g., sink  14  or faucet  18  it is packaged with) and not dependent on the particular installation conditions. With the installation and setup complete, the recognition system  20  is initialized and starts to monitor the detections zone  58  at step  70 . During monitoring, photon pulses are sent from the light emitter  34  at step  74 . Detected photons are received by the position return sensor  42  and analyzed at step  78 . If the detected photons are correlated at step  82 , then the optical filtering is executed at step  86 . If the detected photons are not correlated at step  82 , then the recognition system  20  takes no action and continues sending photon pulses at step  74 . If the optical filtering at step  86  determines that the detected photons were ambient, then the recognition system  20  takes no action and continues sending photon pulses at step  74 . If the optical filtering determines that the returned photons were emitted from the light emitter  34 , then the controller  26  analyzes the distance data returned by the time-of-flight sensor  22  at step  90  to determine if the target object  54  is within the defined detection zone  58 . If the target object  54  is within the detection zone  58  at step  90 , the controller  26  communicates to actuate the water valve  30  at step  94  and water flows through the faucet  18  into the sink  14 . If the target object  54  is outside the detection zone  58 , no action is taken and the recognition system  20  continues sending photon pulses at step  74 . 
         [0044]    Similarly, when water is flowing, the recognition system  20  can continue to monitor the detection zone  58  and deactivates the water valve  30  when the target object  54  leaves the detection zone  58 . The detection zone is not affected by the water flowing. The sensor can be appropriately placed and calibrated depending on the fixture being used. 
         [0045]    A number of alternative arrangements are possible within the scope of the above disclosure. For example, a similar recognition system could be used for toilet flush activation, ensuring that a flush only occurs when a user exits the toilet area. Alternatively, a towel dispenser could be arranged to only pay out towels when a user&#39;s hand is within a predefined area relative to the dispenser. Numerous alternatives exist and will be recognized by those skilled in the art. 
         [0046]    The time-of-flight sensor  22  offers several advantages to more convention proximity detectors. Target object color and texture do not adversely affect performance, the recognition system  20  is substantially immune to ambient light issues, it provides a well defined detection zone  58 , and adjacent surfaces (for example, the sink  14 ) are ignored and do not trigger false activation. 
         [0047]    While there has been shown and described what are at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention defined by the appended claims.