Control of an airflow appliance

Abstract

A controller 10 for an airflow appliance 16 determines a presence of a first 2 and second user 4. A position of the first user relative to the airflow appliance and a position of the second user relative to the airflow appliance is determined. Command data corresponding to a command 8 is received and based on the command data an originating position of the command relative to the airflow appliance is determined. A first distance from the command originating position to the position of the first user, and a second distance from the command originating position to the position of the second user is determined. When the first distance is less than the second distance determine that the command is from the first user and based on the position of the first user and on the command being from the first user control the airflow appliance to emit an airflow 18. The controller may receive an image (24, fig 2) from an imaging system 12 to determine coordinates of the first and second user. The command may be a light or audio signal or one or more gesture, face or voice recognition via a smart device 6.

Description

BACKGROUND Airflow appliances are configured to output an airflow, for example, for thermal comfort of a user. SUMMARY A first aspect of the present disclosure provides a controller for an airflow appliance, the controller configured to: determine a presence of a first user and a second user; determine a position of the first user relative to the airflow appliance and a position of the second user relative to the airflow appliance; receive command data corresponding to a command; determine, based on the command data, an originating position of the command relative to the airflow appliance; determine a first distance from the command originating position to the position of the first user, and a second distance from the command originating position to the position of the second user; determine, when the first distance is less than the second distance, that the command is from the first user; and control, based on the position of the first user, and based on the command being from the first user, the airflow appliance to emit an airflow. Providing the controller configured to: determine, when the first distance is less than the second distance, that the command is from the first user; and control, based on the position of the first user, and based on the command being from the first user, the airflow appliance to emit an airflow may facilitate improved convenience of use of the airflow appliance for the first user. For example, the first user can be targeted or avoided by the airflow without the user having to manually direct or redirect the airflow. Further, the first user, from the first user and the second user, may be selected and tracked by the airflow, improving convenience of use of the airflow appliance. The controller being configured to: determine that the command is from the first user; and control, based on the position of the first user, and based on the command being from the first user, the airflow appliance to emit an airflow may facilitate the first user being selected from the first user and the second user, and then the airflow being emitted as desired. For example, the airflow may be directed towards the first user, track the first user, or be directed away from the first user. Further, this may allow improved user thermal comfort, as a user or a part of a user (e.g., legs or head) can be more accurately targeted or avoided by the airflow without either of the first user or the second user having to manually target the airflow. The command may comprise a light signal generated by a device. The command may comprise an audio signal. The command comprising an audio signal may allow the audio signal (and in some such examples, the command) to be generated by the first user without the need for a device. For example, the user may generate an audio signal using their voice, as other signals may require the user to use a device to generate the command. The command may comprise signals based on one or more of gesture recognition, facial recognition, voice recognition, and / or selection via a smart device. The first user may use the device to generate a further command to control the airflow appliance to emit the airflow towards or away from the second user. The controller may therefore control, based on the position of the second user, and based on the further command being from the first user, the airflow appliance to emit the airflow. This may facilitate the improved convenience of use of the airflow appliance for the second user. The command may comprise the further command. The controller may be configured to: receive an image from an imaging system; determine, based on the image, coordinates of the first user in the image and coordinates of the second user in the image; determine, based on the coordinates of the first user in the image, the position of the first user relative to the airflow appliance; and determine, based on the coordinates of the second user in the image, the position of the second user relative to the airflow appliance. The first, second, and / or third coordinates of the target user may be defined relative to at least a portion of the airflow appliance, such as the imaging system. The controller may be configured to: determine the coordinates of the first user in the image by determining a first bounding box in the image; and determine the coordinates of the second user in the image by determining a second bounding box in the image. Determining the coordinates by determining the bounding boxes for each user may be more computationally efficient than other methods of determining the coordinates of the users. This may allow, when the controller is in use, the controller to run at a faster rate than other methods. The coordinates of the first user in the image may be the coordinates of the first bounding box and / or the coordinates of the second user in the image may be the coordinates of the second bounding box. The coordinates of the first user in the image may be based on the coordinates of the first bounding box and / or the coordinates of the second user in the image may be based on the coordinates of the second bounding box. For example, the coordinates of the first user may be coordinates of a centroid of the first bounding box and / or the coordinates of the second user may be coordinates of a centroid of the second bounding box. The controller may be configured to: determine the coordinates of the first user in the image by determining a first skeletal model of the first user in the image, the first skeletal model corresponding to coordinates of one or more body parts of the first user; and determine the coordinates of the second user in the image by determining a second skeletal model of the second user in the image, the second skeletal model corresponding to coordinates of one or more body part of the second user. This may, when the controller is in use, facilitate more accurate determination of the coordinates of the users in the image (for example, compared to determining the coordinates by determining a single point corresponding to each user), and thus more accurate determination that the first distance is less than the second distance and thus more reliable determination that the command is from the first user. The coordinates of the first user in the image may be based on the first skeletal model, and / or the coordinates of the second user in the image may be based on the second skeletal model. For example, the first skeletal model may comprise coordinates corresponding to one or more body part of the first user and the coordinates of the first user in the image may be the coordinates corresponding to the one or more body part of the first user from the first skeletal model. Similarly, the second skeletal model may comprise coordinates corresponding to one or more body part of the second user and the coordinates of the second user in the image may be the coordinates corresponding to the one or more body part of the second user from the second skeletal model. The image may comprise at least one of: infrared image data, visible-light image data, light detection and ranging data (LiDAR), and radio detection and ranging (radar) data. This may facilitate the controller, when in use, to more accurately identify the first user and the second user from the image, compared to with an image consisting of other image data types and / or to more accurately determine coordinates of the first user and coordinates of the second user, compared to with an image consisting of other image data types. The image may comprise image data from a plurality of sources. Such an image may be referred to as a compound image. Compared to an image not comprising image data from a plurality of sources, providing the image comprising image data from a plurality of sources may facilitate the controller, when in use, to more accurately determine coordinates of the first user in the image and coordinates of the second user in the image and / or to more accurately identify the first user and the second user from the image. The image may be a three-dimensional image. The image being a three-dimensional image may allow the controller to, when in use, more accurately determine, based on the coordinates of the users in the image, the positions of the users relative to the airflow appliance compared to the image being a two-dimensional image. This is because, e.g., such a three-dimensional image allows calculation of the distance from the imaging system to the users from the image rather than requiring an inference or ranging data to be used. The image may be a two-dimensional image. This may allow the imaging system to be configured to acquire two-dimensional images, rather than a comparatively more expensive imaging system configured to acquire three-dimensional images, allowing the cost of the imaging system to be reduced. The image being a two-dimensional image may allow the controller, when in use, to require less processing power to, based on the image, determine coordinates of a first user and coordinates of a second user compared to the image being a three-dimensional image. The controller may be configured to determine the positions of the users relative to the airflow appliance, and / or the originating position of the command relative to the airflow appliance from the two-dimensional image based on an inference from the two-dimensional image. For example, the two-dimensional size of a reference object in the image may be compared to the known actual size of the reference object to infer the distance from the imaging system to the reference object. This may facilitate, when the controller is in use, determination of the positions of the users and / or the originating position of the command in three-dimensional space from the two-dimensional image. The inference may comprise a two-dimensional size in the image of a head of the first user and / or a two-dimensional size in the image of a head of the second user. In such examples, the actual size of the head of the first user and / or second user may be approximated using, e.g., an average head size and therefore the distance from the imaging system to the head of the first user and / or second user may be approximated. Head size of users has a proportionally lesser variance than the variance in other dimensions of other body parts of users such as torso length or height. So, an approximation using the average head size may be more accurate than other approximations, such as approximations using an average torso length. Thus, the inference comprising two-dimensional size in the image of a head of the first user and / or second user may facilitate more accurate determination of the distance from the imaging system to the users than inferences consisting of dimensions of other body parts of the users and therefore more accurate determination of the coordinates of the users. The inference may comprise a two-dimensional size of at least one of: a head and shoulders of the first user; a head and shoulders of the second user; an interpupillary distance of the first user; and an interpupillary distance of the second user. The inference may comprise a first size in the image of at least a portion of the first user and / or a second size in the image of at least a portion of the second user. The first size in the image may be based on a first separation distance in the image between at least two features belonging to the first user. The second size in the image may be based on a second separation distance in the image between the at least two features belonging to the second user. In some examples, the first and / or second separation distance may be between the eyes of the first and / or second user respectively, or between a knee and a foot of the first and / or second user respectively. In such examples, the actual first and / or second separation distance may be approximated using, e.g., an average separation distance between the at least two features, and therefore the distance from the imaging system to the first and / or second user respectively may be approximated. In some examples, the first and / or second separation distance in the image may be based on a number of pixels between the at least two features in the image. In other examples, the first and / or second separation distance in the image may be based on a distance between coordinates of each of the at least two features estimated from the image. The controller may be configured to: determine, based on the image, an activity of the first user; and control, based on the activity, the airflow appliance to emit the airflow. This may facilitate control of the airflow appliance to be tailored to the determined activity. For example, with the activity being determined as exercise, the controller may be configured to control the airflow appliance to cool the airflow and emit the airflow. The command data may be a component of the image, and the controller may be configured to determine, based on the command data, the command coordinates in the image, and determine, based on the command coordinates in the image, the originating position of the command relative to the airflow appliance. This may facilitate, when the controller is in use, the originating position of the command relative to the airflow appliance to be determined from the image by the controller. The controller may be configured to at least one of: determine, based on the image, an identity of the first user, and control, based on the identity of the first user, the airflow appliance to emit the airflow; and determine, based on the image, an identity of the second user, and control, based on the identity of the second user, the airflow appliance to emit the airflow. This may improve the convenience of use of the airflow appliance when the airflow appliance is in use as the first and / or second user’s identity can be used to tailor the control of the airflow appliance to emit the airflow in line with the first and / or second user’s preferences without the need for intervention of the first and / or second user. The controller may be configured to control or adjust, based on the position or coordinates of the first user, one or more operating parameters of the airflow appliance. The controller may be configured to at least one of: control, based on the position and / or coordinates of the first user, and based on the command being from the first user, the airflow appliance to emit the airflow towards at least a part of the first user; and control, based on the position and / or coordinates of the first user, and based on the command being from the first user, the airflow appliance to emit the airflow away from the first user. This may facilitate the airflow appliance to more accurately emit the airflow in the direction where it is wanted (at or away from the first user) rather than not being directed where it is wanted. This may allow, for example, the controller using the position and / or coordinates of the first user to determine the direction in which the airflow is emitted. As a consequence, the airflow may be more accurately emitted in the desired direction (at or away from the user). Thus, this may facilitate a user of the airflow appliance to achieve, when the controller is in use, the desired effect of the airflow using a lesser velocity of the airflow and / or mass flow of the airflow, therefore potentially reducing energy consumption of the airflow appliance. The controller may be configured to determine, based on the image, and using facial recognition, an identity of the first user. This may facilitate, when the controller is in use, accurate identification of the first user compared to other identification methods because of unique features of the first user’s face. Further, facial recognition may facilitate identification of the first user without the first user having to act, such as making a voice command thus improving the convenience of use of the airflow appliance for the first user. The controller may be configured to determine, based on the image, and using facial recognition and voice recognition, an identity of the target user. This may facilitate, when the controller is in use, more accurate identification of the first user compared to other identification methods because of unique features of the first user’s face and voice. The command may comprise an identifier, and the command data may comprise identifier data corresponding to the identifier. This may facilitate the controller, when in use, to receive the command data more reliably because (otherwise received) false positives not comprising the identifier can be recognised by the controller as false positives and ignored by the controller. The command may comprise an identifier; the command data may comprise identifier data corresponding to the identifier; and the controller may be configured to, determine, based on the identifier data, an identity of the first user; and the controller may be configured to control, based on the identity of the first user, the airflow appliance to emit the airflow. This may improve the convenience of use of the airflow appliance when the airflow appliance is in use by the first user as the first user’s identity can be used to tailor the control of the airflow appliance to emit the airflow to what the first user wants without the need for intervention of the first user. The command may comprise voice command; and the controller may be configured to, control, based on the voice command, the airflow appliance to emit the airflow. This may improve the convenience of use of the airflow appliance when the airflow appliance is in use by the first user as the first user generating a voice command may be more convenient than other ways of the first user interacting with the controller. The controller may be configured to control at least one of: a motor to control a pitch of an airflow outlet from which the airflow appliance, when in use, emits the airflow; a motor to control a roll of the airflow outlet; or a motor to control a yaw of the airflow outlet. This may allow the controller, when in use, to direct or redirect the airflow. Pitch may be referred to as tilt. Yaw may be referred to as pan. The controller may be configured to control the airflow appliance to emit the airflow in at least one of: one axis (one of pitch, roll, and yaw), two axes (two of pitch, roll, and yaw), and three axes (each of pitch, roll, and yaw). The controller may be configured to control, based on the coordinates of the first user, and based on the command being from the first user, a heater of the airflow appliance to heat the airflow. This may facilitate the controller, when in use, providing improved thermal comfort to a user. The controller may be configured to control, based on the position of the first user, and based on the command being from the first user, a cooler of the airflow appliance to cool the airflow. This may facilitate the controller, when in use, providing improved thermal comfort to a user. In some examples, the controller may be part of or integrated within the airflow appliance. In other examples, the controller may be separate to the airflow appliance. A second aspect of the present disclosure provides a control system for an airflow appliance, the control system comprising the controller of the first aspect of the present disclosure. The control system may comprise an imaging system configured to output an image to the controller. The command may be a first command and the imaging system may be configured to obtain the image in response to at least one of: the first command, or a second command from the first user or the second user. This may facilitate the airflow appliance, when in use, to consume less energy compared to other configurations as the imaging system will not consume energy obtaining an image that is not required. The imaging system may comprise at least one of: an infrared imaging system configured to obtain infrared image data for the image and output at least part of the image to the controller; a visible-light imaging system configured to obtain visible light image data for the image and output at least part of the image to the controller; a light detection and ranging (LiDAR) system configured to obtain LiDAR image data for the image and output at least part of the image to the controller; and a radio detection and ranging (radar) system configured to obtain radar image data for the image and output at least part of the image to the controller. This may facilitate the control system, when in use, to more accurately identify the first user and the second user from the image, compared to an image consisting of other image data types. This may facilitate the control system, when in use, to more accurately determine the position and / or coordinates of the first user and the position and / or coordinates of the second user, compared to an image consisting of other image data types. The control system may comprise at least one audio detector configured to: detect the command; and output the command data to the controller. This may allow determination of the command coordinates from the command data by comparing what is detected by the at least one audio detector, when the controller is in use. The at least one audio sensor may facilitate identification of the target user, for example by speech recognition or a preset sound such as a clap or a phrase. The control system may comprise a device; the device may comprise a light source configured to generate a light signal; and the command may comprise the light signal. This may facilitate more reliable determination of the command originating position and / or the command coordinates in the image, when the controller is in use, compared to some visual signals. The light source may comprise an infrared light emitting diode; and the light signal may comprise an infrared light signal. A third aspect of the present disclosure provides an airflow appliance comprising the controller of the first aspect of the present disclosure or the control system according to the second aspect of the present disclosure. The airflow appliance may be floor-standing. This may allow the airflow appliance to be moved by a user and / or placed freely by a user without the need for, for example, being wall mounted or otherwise installed. That is, the airflow appliance may be portable. The airflow appliance may comprise a thermal comfort machine configured to heat the airflow and / or cool the airflow when in use. This may facilitate the airflow appliance to provide improved thermal comfort to a user when the airflow appliance is in use. The airflow appliance may comprise a heater configured to heat the airflow when in use. This may facilitate the airflow appliance to provide improved thermal comfort to a user when the airflow appliance is in use. The airflow appliance may comprise a cooler configured to cool the airflow when in use. This may facilitate the airflow appliance to provide improved thermal comfort to a user when the airflow appliance is in use. The airflow appliance may comprise at least one of: a fan, an air purifier, a heater, an air conditioner, a humidifier, or a dehumidifier. A fourth aspect of the present disclosure provides a method of controlling an airflow appliance, the method comprising: determining a presence of a first user and a second user; determining a position of the first user relative to the airflow appliance and a position of the second user relative to the airflow appliance; receiving command data corresponding to a command; determining, based on the command data, an originating position of the command relative to the airflow appliance; determining a first distance from the command originating position to the position of the first user, and a second distance from the command originating position to the position of the second user; determining, when the first distance is less than the second distance, that the command is from the first user; and controlling, based on the position of the first user, and based on the command being from the first user, the airflow appliance to emit an airflow. The method may comprise: determining, at a controller of the first aspect, a presence of a first user and a second user; determining, at the controller, a position of the first user relative to the airflow appliance and a position of the second user relative to the airflow appliance; receiving, at the controller, command data corresponding to a command; determining, at the controller and based on the command data, an originating position of the command relative to the airflow appliance; determining, at the controller, a first distance from the command originating position to the position of the first user, and a second distance from the command originating position to the position of the second user; determining, at the controller, when the first distance is less than the second distance, that the command is from the first user; and controlling, by the controller, and based on the position of the first user, and based on the command being from the first user, the airflow appliance to emit an airflow. The method may comprise: receiving an image from an imaging system; determining, based on the image, coordinates of the first user in the image and coordinates of the second user in the image; determining, based on the coordinates of the first user, the position of the first user relative to the airflow appliance; and determining, based on the coordinates of the second user, the position of the second user relative to the airflow appliance. The method may comprise: determining the coordinates of the first user by determining a first bounding box in the image; and determining the coordinates of the second user by determining a second bounding box in the image. The method may comprise: determining the coordinates of the first user by determining a first skeletal model of the first user in the image, the first skeletal model corresponding to coordinates of one or more body part of the first user; and determining the coordinates of the second user by determining a second skeletal model of the second user in the image, the second skeletal model corresponding to coordinates of one or more body part of the second user. The method may comprise determining the positions of the users relative to the airflow appliance, and / or the originating position of the command relative to the airflow appliance from the two-dimensional image based on an inference from the two-dimensional image. The method may comprise: determining, based on the image, an activity of the first user; and controlling, based on the activity of the first user, the airflow appliance to emit the airflow. The command data may be a component of the image; and the method may comprise determining, based on the command data, the command coordinates in the image, and determining, based on the command coordinates in the image, the originating position of the command relative to the airflow appliance. The method may comprise at least one of: determining, based on the image, an identity of the first user, and controlling, based on the identity of the first user, the airflow applicant to emit the airflow; and determining, based on the image, an identity of the second user, and controlling, based on the on the identity of the first user, the airflow appliance to emit the airflow. The method may comprise, based on the image, and using facial recognition, determining an identity of the first user. The method may comprise, based on the image, and using facial recognition and voice recognition, determining an identity of the first user. The method may comprise adjusting, based on the position or coordinates of the first user, one or more operating parameters of the airflow appliance. The method may comprise at least one of: controlling, based on the position of the first user, and based on the command being from the first user, the airflow appliance to emit the airflow towards the first user; and controlling, based on the position of the first user, and based on the command being from the first user, the airflow appliance to emit the airflow away from the first user. The command may comprise an identifier; the command data may comprise identifier data corresponding to the identifier; the method may comprise determining, based on the identifier data, an identity of the first user; and the method may comprise controlling, based on the identity of the first user, the airflow appliance to emit the airflow. The command may comprise a light signal, and the method may comprise generating, at a light source of the device, the light signal, and at least one of: (A) detecting, at an imaging system, the light signal; generating, at the imaging system and based on light signal, the command data corresponding to the command; and transmitting, from the imaging system to the controller, the command data; and (B) detecting, at a detector of the airflow appliance, the light signal; generating, at the detector and based on light signal, the command data corresponding to the command; and transmitting, from the detector to the controller, the command data. The command may comprise a voice command; and the method may comprise controlling, based on the voice command, the airflow appliance to emit the airflow. The command may be a first command, and the method may comprise: receiving a second command from at least one of the first user or the second user; and controlling the airflow appliance based on the second command. The method may comprise controlling, based on the coordinates of the first user, and based on the command being from the first user, a thermal comfort machine of the airflow appliance to heat the airflow and / or cool the airflow. The method may comprise controlling, based on the coordinates of the first user, and based on the command being from the first user, a heater of the airflow appliance to heat the airflow. The method may comprise controlling, based on the coordinates of the first user, and based on the command being from the first user, a cooler of the airflow appliance to cool the airflow. The method may comprise controlling, based on the coordinates of the first user, and based on the command being from the first user, at least one of: a motor to control a pitch of an airflow outlet from which the airflow appliance, when in use, emits the airflow; a motor to control a roll of the airflow outlet; or a motor to control a yaw of the airflow outlet. The method may comprise, based on the coordinates of the first user, and based on the command being from the first user, directing or redirecting the airflow. The method may comprise controlling, based on the coordinates of the first user, and based on the command being from the first user, the airflow appliance to emit the airflow in at least one of: one axis (one of pitch, roll, and yaw), two axes (two of: pitch, roll, and yaw), and three axes (all of pitch, roll, and yaw). A fifth aspect of the present disclosure provides a non-transitory computer-readable storage medium comprising instructions that, when executed, cause operation of the controller of the first aspect, for example to perform the method of the fourth aspect. Optional features of aspects of the present disclosure may be equally applied to other aspects of the present disclosure, where appropriate. Brief Description of the Drawings Figure 1 schematically shows a top-down view of an example airflow appliance and device when in use; Figures 2 and 3 schematically show images obtained by an imaging system of the airflow appliance with bounding boxes and skeletal models superimposed respectively; Figure 4 is a block diagram of a control system of the airflow appliance; Figure 5 is a flow diagram of a method of controlling the airflow appliance; and Figure 6 is a block diagram of an alternative control system. Detailed Description of the Invention An example airflow appliance 16 is described with reference to Figures 1 to 5. The airflow appliance 16 is a freestanding fan (e.g., a portable fan). The airflow appliance 16 has an imaging system 12, a user interface 34, a temperature sensor 36, a controller 10, an airflow outlet 14, an actuator assembly 60, an airflow inlet 20, a blower 62, and a heater 64. The airflow appliance 16 is controllable by a device 6. A control system 46 (shown in Figure 4) of the airflow appliance 16 includes the imaging system 12, the user interface 34, the temperature sensor 36, the controller 10, the actuator assembly 60, the blower 62, and the heater 64. The imaging system 12 has an integrated circuit, such as a charge-coupled device (CCD), configured to obtain an image 24 of a scene located in front of the airflow appliance 16. In this example, a CCD has a 2D array of pixel elements that is configured to obtain images comprising 2D and visible-light data. The CCD is configured with sufficient resolution to resolve features of a face of a first user 2 and a second user 4 of the airflow appliance, for example, at a distance of 5 metres. The imaging system 12 is connected to the controller 10 by a first data cable. The user interface 34 has user-operable controls for controlling operation of the airflow appliance 16, including, for example, a dial for controlling a speed of the blower 62, a button for powering on and off the airflow appliance 16, a first control for switching between operational modes, and a second control for manually adjusting a direction of a central axis 22 of the airflow outlet 14. Further, the user interface 34 has an infrared CCD sensor for receiving an infrared signal from the device 6. The user interface 34 is connected to the controller 10 by a second data cable. Other user-operable controls are envisaged. The temperature sensor 36 has a first thermocouple configured to obtain first temperature data indicative of an ambient temperature and a second thermocouple configured to obtain second temperature data indicative of a temperature of an airflow 18 emitted by the airflow appliance 16. The temperature sensor 36 is connected to the controller 10 by a third data cable. The controller 10 is connected to the imaging system 12 by the first data cable, the user interface 34 by the second data cable, the temperature sensor 36 by the third data cable, the actuator assembly 60 by a fourth data cable, the blower 62 by a fifth data cable, and the heater 64 by a sixth data cable. The controller 10 has a computer processor, storage, and a printed circuit board (PCB). The storage is readable by the computer processor, and stores instructions for the computer processor, calibration data, and look-up tables. The PCB connects the computer processor to the storage, the first data cable, the second data cable, the third data cable, the fourth data cable, the fifth data cable, and the sixth data cable. The airflow outlet 14 is rotatable around about a first rotational axis (yaw), a second rotational axis (pitch), and a third rotational axis (roll). The first, second, and third rotational axes are mutually orthogonal. Rotation of the airflow outlet 14 about the first rotational axis causes a central axis 22 of the airflow outlet 14 to precess about the first rotational axis. Likewise, rotation of the airflow outlet 14 about the second rotational axis causes the central axis 22 to precess about the second rotational axis, and rotation of the airflow outlet 14 about the third rotational axis causes the central axis 22 to precess about the third rotational axis. Rotation about the first rotational axis adjusts the yaw of the airflow outlet 14, rotation about the second rotational axis adjusts the pitch of the airflow outlet 14, and rotation about the third rotational axis adjusts the roll of the airflow outlet 14. The actuator assembly 60 is attached to the airflow outlet 14. The actuator assembly 60 has a first motor 54, a second motor 56, and a third motor 58. Each of the first 54, second 56, and third motor 58 may be a servomotor. The first motor 54 is operable to adjust the yaw of the airflow outlet 14, the second motor 56 is operable to adjust the pitch of the airflow outlet 14, and the third motor 58 is operable to adjust the roll of the airflow outlet 14. The actuator assembly 60 is connected to the controller 10 by the fourth data cable. The blower 62 has a fourth motor and an impeller. The fourth motor is attached to the impeller and is operable to rotate the impeller. The impeller is fluidly connected to the airflow inlet 20 by a first airflow conduit, and to the heater 64 by a second airflow conduit. The blower 62 is connected to the controller 10 by the fifth data cable. The heater 64 has a heating element. The heater 64 is located downstream of the blower 62, is fluidly connected to the blower 62 by the second airflow conduit and is fluidly connected to the airflow outlet 14 by a third airflow conduit. The heating element is positioned between the airflow inlet 20 and the airflow outlet 14. A temperature of the heating element is dependent on an electrical current through the heating element. The heater 64 is connected to the controller 10 by the sixth data cable. The device 6 is a remote control and has a light emitting diode (LED) and a button for controlling the LED. The LED is configured to emit a light signal when the button is operated. In use, the airflow appliance 16 is powered on by a first user 2 or a second user 4 by operating the button of the user interface 34. The airflow appliance 16 is then put into a tracking mode by the first user 2 or the second user 4 by operating the first control of the user interface 34. The user interface 34 outputs to the controller 10, by the second data cable, the user interface data including the instructions for the airflow appliance 16 to be powered on and be in tracking mode. The controller 10 receives the user interface data and accordingly powers on the airflow appliance 16 and operates in tracking mode. The first user 2 then operates the button of the device 6, resulting in the LED of the device 6 generating the light signal that is a command 8. With the controller 10 operating in tracking mode, the controller 10 instructs, by the first data cable, the imaging system 12 to obtain the image 24. Accordingly, the integrated circuit (e.g., a CCD) of the imaging system 12 obtains the image 24. The image 24 is of the first user 2, the second user 4, and the command 8. The imaging system 12 then outputs the image 24 to the controller 10 by the first data cable. With the controller 10 is operating in tracking mode, the controller 10 instructs, by the third data cable, the temperature sensor 36 to obtain the first temperature data and the second temperature data. Accordingly, the temperature sensor 36, with the first thermocouple and the second thermocouple respectively, obtains the first temperature data and the second temperature data. The temperature sensor 36 then outputs the first and second temperature data to the controller 10 by the third data cable. The controller 10 receives the image 24 from the imaging system 12, and the first and second temperature data from the temperature sensor 36. The controller 10, with the image 24 and using a first computer vision algorithm, determines a presence of the first user 2 and the second user 4. The controller 10 determines facial recognition data associated with a face of the first user 2 using a facial recognition algorithm and the image 24. The controller 10 then, based on the facial recognition data, determines an identity of the first user 2 using a first look-up table stored in the storage. As shown in Figure 2, the controller 10 determines a first bounding box 26 and a second bounding box 28 using a bounding box algorithm. The bounding boxes 26 and 28 are in the image 24 and associated with the first user 2 and the second user 4 respectively. As shown in Figure 3, the controller 10 determines a first skeletal model 30 corresponding to coordinates of one or more body part of the first user 2, and a second skeletal model 32 corresponding to coordinates of one or more body part of the second user 4 using a skeletal model algorithm. The skeletal models 30 and 32 are in the image 24. The controller 10 determines coordinates (x, y) of the first user 2 and the second user 4 within the image 24 using a second computer vision algorithm, the bounding boxes 26, 28, and the skeletal models 30, 32. The controller 10 determines positions of the of the first user 2 and the second user 4 in three dimensions (x, y, z) relative to the airflow appliance 16 based on inferences from the image 24 based on two-dimensional sizes of a head of the first user 2 and a head of the second user 4 in the image 24. Actual sizes of the heads of the first and second users 2, 4 are approximated as an average head size stored in the storage of the controller 10. Distances from the imaging system 12 to the head of the first user 2 and the head of the second user 4 are approximated by the controller 10 by comparing the sizes of the heads in the image 24 to the average head size. The positions of the of the first and second users 2, 4 are then determined in three dimensions (x, y, z) based on the coordinates (x, y) of the first and second users 2, 4 in the image 24 and the respective distances from the imaging system 12 to the first and second users 2, 4. The image 24 has command data corresponding to the command 8 in the image 24. The controller 10 determines the coordinates of the command 8 within the image 24 using a third computer vision algorithm and the command data. Based on the coordinates of the command 8 within the image 24, the controller 10 then determines an originating position of the command 8 relative to the airflow appliance in two dimensions (x, y). The controller 10 determines a first distance from the originating position of the command 8 to the position of the first user 2, and a second distance from originating position of the command 8 to the position of the second user 4. The controller 10 then determines, when the first distance is less than the second distance, that the command 8 is from the first user 2. With the airflow appliance 16 in tracking mode, the controller 10 controls the airflow appliance 16 to emit the airflow 18 in the direction of the first user 2. The controller 10 generates output data for controlling the actuator assembly 60, the blower 62 and the heater 64 so that the airflow 18 is emitted at the first user 2. The output data is based on the identity of the first user 2, the position of the first user 2 relative to the airflow appliance 16, the command 8 being from the first user 2, and the temperature data. The output data includes target yaw, pitch, and roll values (9, (p, y) for the airflow outlet 14, a target speed value (co) for the blower 62, and a target temperature value (T) for the heater 64. The target yaw, pitch, and roll values (0, cp, \p) are such that the central axis 22 of the airflow outlet 14 tracks the first user 2 and thus the airflow 18 is emitted from the airflow outlet 14 towards (or away from) the first user 2. The target speed value (co) is determined by the controller 10 based on a speed preference of the first user 2. The speed preference of the first user 2 is associated with the identity of the first user 2 and is determined by the controller 10 using a second look-up table stored in the storage. The target temperature value (T) is determined by the controller 10 based on a temperature preference of the first user 2 and the temperature data. The temperature preference of the first user 2 is associated with the identity of the first user 2 and is determined by the controller 10 using a third look-up table stored in the storage. The controller 10 outputs the target yaw, pitch, and roll values (0, (p, \g) to the actuator assembly 60 by the fourth data cable, the target speed value (co) to the blower 60 by the fifth data cable, and the target temperature value (T) to the heater 64 by the sixth data cable. The actuator assembly 60 receives the target yaw, pitch, and roll values (0, cp, \p) from the controller 10 by the fourth data cable, and accordingly controls the first 54, second 56, and third motor 58 to direct the central axis 22 of the airflow outlet 14 at the first user 2. The blower 62 receives the target speed value (co) from the controller 10 by the fifth data cable, and accordingly controls the fourth motor. The fourth motor rotates the impeller which draws air in through the airflow inlet 20, from the airflow inlet 20 to the blower 62 by the first airflow conduit, from the blower 62 to the heater 64 by the second airflow conduit, from the heater 64 to the airflow outlet 14 by the third airflow conduit, and out of the airflow outlet 14, thus moving air through the airflow appliance 16 and causing emission of the airflow 18 from the airflow outlet 14. The heater 64 receives the target temperature value (T) from the controller 10 by the sixth data cable, and accordingly controls the electrical current through the heating element. Part of the air moving through the airflow appliance 16 from the airflow inlet 20 to the airflow outlet 14 by the heater contacts the heating element. Heat is transferred from the heating element to the air moving through the airflow appliance 16 and thus a temperature of the airflow 18 is controlled. Tracking mode can be suspended by the first user 2 or the second user 4 using the user interface 34, and the direction of the central axis 22 of the airflow output 14 can be controlled manually by the first user 2 or the second user 4. The airflow appliance 16 may facilitate improved convenience of use of the airflow appliance 16 for the first user 2 as the first user 2 is targeted by the airflow 18 without the first user 2 having to manually direct or redirect the airflow 18. Further, the first user 2, from the users 2, 4 is selected and tracked by the airflow 18, thus improving the convenience of use for the users 2,4. A method 66 in accordance with the above is illustrated in the flow diagram of Figure 5. The method 66 comprises determining 68 the presence of the first user 2 and the second user 4, and determining 70 the position of the first user 2 relative to the airflow appliance 16 and the position of the second user 4 relative to the airflow appliance 16. The method 66 includes receiving 72 command data corresponding to the command 8, and determining 74, based on the command data, the originating position of the command 8 relative to the airflow appliance 16. The method 66 includes determining 76 the first distance from the command originating position to the position of the first user 2, and the second distance from the command originating position to the position of the second user 4. The method comprises determining 78, when the first distance is less than the second distance, that the command 8 is from the first user 2, and controlling 80, based on the position of the first user 2, and based on the command being from the first user 2, the airflow appliance 16 to emit the airflow 18. The method 66 is implemented by the controller 10. Figure 6 shows an alternative control system 48. The control system 46 described above and the alternative control system 48 are substantially the same. However, in the alternative control system 48 the imaging system 12 is replaced with an audio detector system 38, the command 8 is audio signal rather than a light signal, and the airflow appliance 16 is not controlled with the device 6. The audio detector system 38 has a first audio detector 40 and a second audio detector 42 and is connected to the controller 10 by a seventh data cable. Both the first audio detector 40 and the second audio detector 42 are microphones. Controlling the airflow appliance 16 with the alternative control system differs from controlling the airflow appliance 16 with the control system 46 as described above in relation to Figures 1 to 5 in that the first user 2 generates the command 8 without using the device 6, e.g., by stamping their foot or clapping or speaking a predetermined phrase. Then, the audio detectors 40, 42 detect the command 8. The audio detector system 38 then outputs, to the controller 10 and by the seventh cable, command data corresponding to the command 8 detected by the audio detectors 40, 42. The controller 10 then determines the originating position of the command 8 based on a time difference between when the first audio detector 40 detected the command and when the second audio detector 42 detected the command. Whilst examples and embodiments have thus far been described, these are illustrative only and various modifications may be made without departing from the scope of the invention as defined by the claims.

Claims

1. A controller for an airflow appliance, the controller configured to:determine a presence of a first user and a second user;determine a position of the first user relative to the airflow appliance and a position of the second user relative to the airflow appliance;receive command data corresponding to a command;determine, based on the command data, an originating position of the command relative to the airflow appliance;determine a first distance from the command originating position to the position of the first user, and a second distance from the command originating position to the position of the second user;determine, when the first distance is less than the second distance, that the command is from the first user; andcontrol, based on the position of the first user, and based on the command being from the first user, the airflow appliance to emit an airflow.

2. The controller of claim 1, configured to:receive an image from an imaging system;determine, based on the image, coordinates of the first user in the image and coordinates of the second user in the image;determine, based on the coordinates of the first user in the image, the position of the first user relative to the airflow appliance; anddetermine, based on the coordinates of the second user in the image, the position of the second user relative to the airflow appliance.

3. The controller of claim 2, configured to:determine the coordinates of the first user in the image by determining a first bounding box in the image; anddetermine the coordinates of the second user in the image by determining a second bounding box in the image.

4. The controller of claim 2 or claim 3, configured to:determine the coordinates of the first user in the image by determining a first skeletal model of the first user in the image, the first skeletal model corresponding to coordinates of one or more body part of the first user; anddetermine the coordinates of the second user in the image by determining a second skeletal model of the second user in the image, the second skeletal model corresponding to coordinates of one or more body part of the second user.

5. The controller of any of claims 2 to 4, configured to: determine, based on the image, an activity of the first user; and control, based on the activity of the first user, the airflow appliance to emit the airflow.

6. The controller of any of claims 2 to 5, wherein:the command data is a component of the image; andthe controller is configured to determine, based on the command data, the command coordinates in the image, and determine, based on the command coordinates in the image, the originating position of the command relative to the airflow appliance.

7. The controller of any of claims 2 to 6, configured to at least one of:determine, based on the image, an identity of the first user, and control, based on the identity of the first user, the airflow appliance to emit the airflow; anddetermine, based on the image, an identity of the second user, and control, based on the identity of the second user, the airflow appliance to emit the airflow.

8. The controller of any previous claim, wherein the controller is configured to control, based on the position of the first user, one or more operating parameters of the airflow appliance.

9. The controller of any previous claim, the controller configured to at least one of: control, based on the position of the first user, and based on the command being from the first user, the airflow appliance to emit the airflow towards at least a part of the first user; andcontrol, based on the position of the first user, and based on the command being from the first user, the airflow appliance to emit the airflow away from the first user.

10. The controller of any previous claim, wherein:the command comprises an identifier;the command data comprises identifier data corresponding to the identifier;the controller is configured to determine, based on the identifier data, an identity of the first user; andthe controller is configured to control, based on the identity of the first user, the airflow appliance to emit the airflow.

11. A control system for an airflow appliance, the control system comprising the controller of any previous claim.

12. The control system of claim 11, comprising at least one of:an imaging system configured to output an image to the controller; anda device configured to generate the command, the device comprising a light source configured to generate a light signal, and wherein the command comprises the light signal.

13. The control system of claim 11, comprising at least one audio detector configured to detect the command, and output the command data to the controller.

14. An airflow appliance comprising the controller of any of claims 1 to 10, or the control system of any of claims 11 to 13.

15. A method of controlling an airflow appliance, the method comprising:determining a presence of a first user and a second user;determining a position of the first user relative to the airflow appliance and a position of the second user relative to the airflow appliance;receiving command data corresponding to a command;determining, based on the command data, an originating position of the command relative to the airflow appliance;determining a first distance from the command originating position to the position of the first user, and a second distance from the command originating position to the position of the second user;determining, when the first distance is less than the second distance, that the command is from the first user; andcontrolling, based on the position of the first user, and based on the command being from the first user, the airflow appliance to emit an airflow.

16. The method of claim 15, comprising:receiving an image from an imaging system;determining, based on the image, coordinates of the first user in the image and coordinates of the second user in the image;determining, based on the coordinates of the first user, the position of the first user relative to the airflow appliance; anddetermining, based on the coordinates of the second user, the position of the second user relative to the airflow appliance.

17. The method of claim 16, comprising:determining the coordinates of the first user by determining a first bounding box in the image; anddetermining the coordinates of the second user by determining a second bounding box in the image.

18. The method of claim 16 or claim 17, comprising:determining the coordinates of the first user by determining a first skeletal model of the first user in the image, the first skeletal model corresponding to coordinates of one or more body part of the first user; anddetermining the coordinates of the second user by determining a second skeletal model of the second user in the image, the second skeletal model corresponding to coordinates of one or more body part of the second user.

19. The method of any of claims 16 to 18, comprising:determining, based on the image, an activity of the first user; andcontrolling, based on the activity of the first user, the airflow appliance to emit the airflow.

20. The method of any of claims 16 to 19, wherein:the command data is a component of the image; andthe method comprises determining, based on the command data, the command coordinates in the image, and determining, based on the command coordinates in the image, the originating position of the command relative to the airflow appliance.

21. The method of any of claims 16 to 20, comprising at least one of:determining, based on the image, an identity of the first user, and controlling, based on the identity of the first user, the airflow applicant to emit the airflow; anddetermining, based on the image, an identity of the second user, and controlling, based on the on the identity of the second user, the airflow appliance to emit the airflow.

22. The method of any of claims 15 to 21, comprising:adjusting, based on the position of the first user, one or more operating parameters of the airflow appliance.

23. The method of any of claims 15 to 22, comprising at least one of:controlling, based on the position of the first user, and based on the command being from the first user, the airflow appliance to emit the airflow towards the first user; andcontrolling, based on the position of the first user, and based on the command being from the first user, the airflow appliance to emit the airflow away from the first user.

24. The method of any of claims 15 to 23, wherein:the command comprises an identifier;the command data comprises identifier data corresponding to the identifier;the method comprises determining, based on the identifier data, an identity of the first user; andthe method comprises controlling, based on the identity of the first user, the airflow appliance to emit the airflow.

25. The method of any of claims 15 to 24, wherein the command comprises a light signal, and the method comprises:generating, at a light source, the light signal; anddetecting, at a detector of the airflow appliance, the light signal;5 generating, at the detector and based on light signal, the command data correspondingto the command; andtransmitting, from the detector to the controller, the command data.