Patent Description:
The invention further relates to a method of activating an infrared light source or a visible-light light source.

There is a rapid growth in camera surveillance, also in the consumer domain, as a result of IP/Wi-Fi cameras having become compact and relatively cheap. The night vision mode on cameras uses infrared (IR) light to invisibly illuminate the monitored area. This enables unnoticeable camera monitoring without creating any light pollution.

Cameras are rapidly becoming more sophisticated. For instance, some cameras have a wide or <NUM> degrees field-of-view angle. This larger field-of-view inherently means that the accompanying IR illumination must also cover this wider area. Night vision cameras usually have multiple IR LEDs mounted around the lens, to generate the infrared light towards the monitored area. However, a highly concentrated beam of IR located at the position of the camera will cause washing out of parts of the image, while not illuminating other parts.

Given the wide field-of-view, IR lights which are located remote from the camera are necessary to generate a proper night vision view across a larger monitored area. Being able to illuminate from different angles and positions will significantly increase overall image quality. Infrared light sources which are external to the camera device are disclosed in <CIT>, for example.

<CIT> discloses a smart surveillance camera system of which a processor is configured to generate control signals to activate/deactivate or otherwise control operation of IR illuminators, visible light illuminators and/or a visible/NIR light camera based the detection and determination of a presence, type and/or other attributes of an object of interest in the surveillance scene. For example, the visible light illuminators may be controlled if a person is detected and the IR illuminators may be controlled if an animal is detected.

<CIT> further discloses that a user is able to make an association between a detected object type and corresponding illumination/monitoring operations, e.g. if the user prefers IR illuminators to turn on instead of visible light illuminators so that people can be monitored without drawing their attention. However, the user has to configure which type of light source should be activated when human presence is detected, which makes the system behave sub optimally.

<CIT> discloses a smart surveillance camera system including a thermal imager, a visible/NIR light camera, one or more IR illuminators, one or more visible light illuminators, a processor and a communication module. Users may configure the camera system to perform specific illumination and recording operations according to the types of the detected objects. The thermal imager and/or processor may detect and discern animals, vehicles or other objects of interest in scene by detecting and analyzing objects having temperatures typical for objects of interest.

It is a first object of the invention to provide a system, which is able to select a light source for activation in response to human presence detection in a smart manner.

It is a second object of the invention to provide a method, which is able to select a light source for activation in response to human presence detection in a smart manner.

In a first aspect of the invention, a system for activating an infrared light source or a visible-light light source comprises at least one input interface, at least one control interface, and at least one processor configured to receive, via said at least one input interface, input indicating human presence in a space, determine a type of said human presence based on said input, decide whether to activate an infrared light source or a visible-light light source in said space based on said type of said human presence, and activate, via said at least one control interface, said infrared light source or said visible-light light source in dependence on said decision.

By letting the system decide whether to activate an infrared light source or a visible-light light source based on the type of the human presence, it becomes possible to only activate the visible-light light source when the detected person is a known or trusted person has been detected is sufficiently high. This smart selection of a light source to be activated in response to human presence detection may be used to illuminate one or more important areas for occupants of a space, e.g. an area with a door and/or an area with pavement, but only when needed. By not unnecessarily activating the visible-light light source(s), the amount of disturbance to occupants and/or their neighbors may be reduced.

By activating the infrared light source when human presence has been detected but it is not desirable to activate the visible-light light source, intruders can still be recorded/monitored by a camera. As an additional advantage, the intruders are not aware that they are being recorded/monitored. The infrared light source(s), e.g. IR LEDs, may be integrated into a (regular) illumination device or a presence/motion detection device, for example. The infrared light source(s) may be integrated in a device separate from the camera to help ensure that the range of the infrared light source(s) is sufficient to cover (almost) every area and or angle with the camera. The human presence sensing may be enabled by separate or lamp-integrated presence sensing means (e.g. RF-based, microphone, or PIR), for example.

Said system may be a lighting device which comprises said infrared light source and said visible-light light source. For example, if regular lamps are equipped with integrated IR LEDs, those can enable high-quality night vision for surveillance cameras. In order to save energy, the IR LEDs (and optionally the camera) only need to be activated if presence is detected.

The system may be part of a smart home system in which smart lighting devices (comprising RF-based presence sensing) or motion/presence sensors with integrated IR light source(s) are combined with (WiFi) security cameras, for example. Alternatively, the system may be part of an office lighting system that comprises luminaires with integrated presence sensing (e.g. using microwave sensors) and IR LEDs (e.g. used for IR LiFi during daytime), for example. Alternatively, the system may be incorporated into streetlights which comprise an integrated surveillance camera and a simple presence sensor, for example.

Said at least one processor is configured to perform person identification based on said input and/or based on further input and determine said type of said human presence by determining whether said person identification resulted in a known and/or trusted person being identified. This makes it possible to only active the visible-light light source when a known and/or trusted person has been identified and to activate the infrared light source when a different type of human presence has been detected. The infrared light source is sufficient to record/monitor intruders (intruders do not need to be helped to find their way) and may make the camera more difficult for intruders to notice (due to the absence of visible light). The further input may be received from a further device, for instance from a personal mobile device.

Said at least one processor may be configured to receive, via said at least one input interface, one or more signals from one or more personal mobile devices, said one or more signals comprising one or more user identifications, and perform said person identification based on said one or more signals. This enables person identification in a relatively simple manner. The one or more signals may be Bluetooth signals, for example.

Said at least one processor may be configured to determine, via said at least one input interface, one or more characteristics of a set of received radio frequency signals, and perform said person identification based on said one or more characteristics of said set of received radio frequency signals. This enables person identification without requiring every known or trusted person to carry a personal mobile device and without requiring personal mobile devices to be configured to transmit user identifications.

Said at least one processor may be configured to determine an ambient light level via said at least one input interface, determine whether said ambient light level exceeds a light threshold, and activate said infrared light source or said visible-light light source in dependence on said decision upon determining that said ambient light level does not exceed said light threshold. By only activating an artificial light source when the natural light is not sufficient, energy may be saved.

For instance, said at least one processor may be configured to obtain, via said at least one input interface, infrared camera images from a camera device, said infrared camera images being captured while said infrared light source is emitting light, perform further human presence detection based on said infrared camera images, decide whether to activate said visible-light light source based on said further human presence detection, and activate, via said at least one control interface, said visible-light light source based on said decision whether to activate said visible-light light source. This may be used to prevent unnecessary activation of the visible-light light source(s), and flickering in particular, which may unnecessarily disturb occupants or their neighbors.

If the further human presence detection results in the detection of a human, but the detected human cannot be identified, the visible-light light source may be flashed or flickered in order to deter the (likely) intruder, while leaving the infrared light source on continuously to enable capture of continuous video even though the visible-light light source is flashing or flickering.

Said at least one processor may be configured to identify one or more infrared light sources within a certain distance of a device with a camera and select said infrared light source by selecting at least one infrared light source from said one or more infrared light sources. The one or more infrared light sources may be identified based on received signal strengths as measured by the device with the camera, for example.

Alternatively or additionally, said at least one processor may be configured to identify one or more infrared light sources in a field of view of a camera and select said infrared light source by selecting at least one infrared light source from said one or more infrared light sources. For example, during configuration, the camera may detect a (visible or infrared) lighting identifier emitted by the lighting device. This may be achieved by modulating the light of each light source or by sequentially activating individual light sources during the configuration process, for example. Optionally, the IR output of the lighting device may be automatically adjusted such that maximal illumination of the full image is achieved without white-washing.

Said at least one processor may be configured to activate said camera or a camera function in dependence on said decision whether to activate said infrared light source. This is beneficial if the camera does not record continuously.

Said at least one processor may be configured to decide whether to activate a group of infrared light sources in said space based on said type of said human presence, said group comprising a plurality of light sources, and activate and deactivate, via said at least one control interface, each of said group of infrared light sources in sequence in dependence on said decision whether to activate said group of infrared light sources. This temporal control (subsequent activation) of the IR light sources may be used in order to generate an improved image of a detected object (e.g. intruder).

In a second aspect of the invention, a method of activating an infrared light source or a visible-light light source comprises receiving input indicating human presence in a space, determining a type of said human presence based on said input, deciding whether to activate an infrared light source or a visible-light light source in said space based on said type of said human presence, and activating said infrared light source or said visible-light light source in dependence on said decision. Said method may be performed by software running on a programmable device. This software may be provided as a computer program product.

A non-transitory computer-readable storage medium stores at least one software code portion, the software code portion, when executed or processed by a computer, being configured to perform executable operations for activating an infrared light source.

The executable operations comprise receiving input indicating human presence in a space, determining a type of said human presence based on said input, deciding whether to activate an infrared light source or a visible-light light source in said space based on said type of said human presence, and activating said infrared light source or said visible-light light source in dependence on said decision.

As will be appreciated by one skilled in the art, aspects of the present invention are embodied as a system, a method or a computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a "circuit", "module" or "system.

<FIG> shows a first embodiment of the system for activating an infrared light source: a lighting device <NUM>. The lighting device <NUM> comprises a receiver <NUM>, a transmitter <NUM>, a processor <NUM>, a LED module <NUM> and a control interface <NUM> between the processor <NUM> and the LED module <NUM>. The LED module <NUM> comprises a plurality of LEDs: a visible-light LED <NUM> and an IR LED <NUM>.

The processor <NUM> is configured to receive, via the receiver <NUM>, input indicating human presence in the same space as the lighting device <NUM>, determine a type and optionally the probability of the human presence based on the input, decide whether to activate the IR LED <NUM> or the visible-light LED <NUM> based on the type and optionally the probability of the human presence, and activate, via the control interface <NUM>, the IR LED <NUM> or the visible-light LED <NUM> in dependence on the decision.

The input may be received from a separate presence or motion sensor or the receiver <NUM> may be used to perform RF-based sensing, for example. The separate presence or motion sensor may use IR sensing, for example. For instance, low brightness energy saving IR may be used to detect presence and then bright IR may be used for camera vision.

The processor <NUM> may be configured to activate a camera device <NUM> or a camera function of the camera device <NUM> in dependence on the decision whether to activate the IR LED <NUM> or the visible-light LED <NUM>. In the example of <FIG>, the camera device <NUM> is connected to a wireless LAN access point <NUM>, e.g. using Wi-Fi, a (light) controller <NUM> is also connected to the wireless LAN access point <NUM>, e.g. using Wi-Fi or Ethernet, and the lighting device <NUM> is connected to the controller <NUM>, e.g. using Zigbee. The lighting device <NUM> is able to communicate with the camera device <NUM> via the controller <NUM> and the wireless LAN access point <NUM>. The controller <NUM> may be a Philips Hue bridge, for example.

In the example of <FIG>, a mobile device <NUM> is also connected to the wireless LAN access point <NUM>, e.g. via Wi-Fi. The mobile device <NUM> may run an app for controlling the lighting device <NUM>, for example. The mobile device <NUM> may be able to control the lighting device via the wireless LAN access point <NUM> and the controller <NUM> and/or directly, e.g. using Bluetooth. The mobile device <NUM> may also transmit a signal comprising a user identification, e.g. using Bluetooth. The lighting device <NUM> may be configured to use this signal to perform person identification.

The LEDs <NUM>-<NUM> may be direct emitting or phosphor converted LEDs. The visible-light LED <NUM> may be a white LED, for example. In the embodiment of <FIG>, the LED module <NUM> comprises only one visible-light LED <NUM>. In an alternative embodiment, the LED module <NUM> comprises multiple visible-light LEDs, e.g. a red LED, a green LED, a blue LED and optionally a white LED. In the embodiment of <FIG>, the LED module <NUM> comprises only one IR LED <NUM>. In an alternative embodiment, the LED module <NUM> comprises multiple IR LEDs.

In the embodiment of the lighting device <NUM> shown in <FIG>, the lighting device <NUM> comprises one processor <NUM>. In an alternative embodiment, the lighting device <NUM> comprises multiple processors. The processor <NUM> of the lighting device <NUM> may be a general-purpose processor or an application-specific processor. The receiver <NUM> and the transmitter <NUM> may use one or more wireless communication technologies. e.g. Zigbee, for communicating with the controller <NUM>. In an alternative embodiment, multiple receivers and/or multiple transmitters are used instead of a single receiver and a single transmitter.

In the embodiment shown in <FIG>, a separate receiver and a separate transmitter are used. In an alternative embodiment, the receiver <NUM> and the transmitter <NUM> are combined into a transceiver. The lighting device <NUM> may comprise other components typical for a connected lighting device such as a power connector and a memory. In an alternative embodiment, the lighting device <NUM> is not a connected lighting device. The invention may be implemented using a computer program running on one or more processors.

In the embodiment of <FIG>, the system of the invention is a lighting device. In an alternative embodiment, the system of the invention is a different device, e.g. a mobile device or a controller. In the embodiment of <FIG>, the system of the invention comprises a single device. In an alternative embodiment, the system of the invention comprises a plurality of devices.

<FIG> shows a second embodiment of the system for activating an infrared light source: a controller <NUM>, e.g. a bridge or a gateway. In the example of <FIG>, the controller <NUM> controls four lighting devices <NUM>-<NUM>. In the example of <FIG>, lighting devices <NUM> and <NUM> each comprise a visible-light LED <NUM>, lighting device <NUM> comprises an IR LED <NUM>, and lighting device <NUM> comprises both a visible-light LED <NUM> and an IR LED <NUM>.

The controller <NUM> comprises a receiver <NUM>, a transmitter <NUM>, a processor <NUM>, and memory <NUM>. The processor <NUM> is configured to receive, via the receiver <NUM>, input indicating human presence in a space, determine a type and/or probability of the human presence based on the input, decide whether to activate an infrared light source or a visible-light light source in the space based on the type and/or probability of the human presence, and activate, via the transmitter <NUM>, the infrared light source (e.g. of lighting devices <NUM> and/or <NUM>) or the visible-light light source (e.g. of lighting devices <NUM>, <NUM> and/or <NUM>) in dependence on the decision.

In the embodiment of <FIG>, the processor <NUM> is configured to receive light level information from a light sensor <NUM> via the receiver <NUM>, determine an ambient light level from the received light level information, determine whether the ambient light level exceeds a light threshold, and activate the infrared light source or the visible-light light source in dependence on the decision upon determining that the ambient light level does not exceed the light threshold. In the example of <FIG>, the light sensor <NUM> is connected to the wireless LAN access point <NUM>.

In the embodiment of <FIG>, the processor <NUM> is configured to identify one or more infrared light sources in a field of view of the camera of camera device <NUM> or within a certain distance of camera device <NUM> and select the infrared light source by selecting at least one infrared light source from the one or more infrared light sources. A light source may be determined to be in the field of view of a camera when a lighting device comprising the light source or a light effect rendered by the light source can be recognized in an image captured by the camera. A light effect may be recognized in an image, for example, when the light source transmits an identifier coded in the light. In the embodiment of <FIG>, the processor <NUM> is configured to activate the camera of camera device <NUM> in dependence on the decision whether to activate the infrared light source or the visible-light light source.

For example, when both IR LED <NUM> of lighting device <NUM> and IR LED <NUM> of lighting device <NUM> are in the field of view of the camera of camera device <NUM>, then these light sources are both identified, and at least one these light sources is selected. If it is decided to activate an infrared light source, the selected light source(s) are then activated by transmitting a suitable command to lighting device <NUM> or <NUM>. The same principle may be used to identify one or more visible-light light sources. For example, when visible-light LED <NUM> of lighting device <NUM> is in the field of view of camera, then this light source is identified, e.g. using a Visible Light Communication (VLC) identifier, and selected. If it is decided to activate a visible-light light source, the selected light source is then activated by transmitting a suitable command to lighting device <NUM>.

The example described in the previous paragraph is depicted in <FIG> depicts an example of a space <NUM> comprising the camera device <NUM> and lighting devices <NUM>-<NUM> of <FIG>. Lighting devices <NUM>-<NUM> are inside the field of view <NUM> of the camera of camera device <NUM> and lighting device <NUM> is outside the field of view of the camera of camera device <NUM>. During configuration, the camera detects lighting identifiers from lighting devices <NUM>-<NUM> in its field of view.

At night (when the lights are off or low) the camera and the IR LEDs in those lighting devices are activated upon detecting presence, e.g. of person <NUM>, in the monitored area based on the type and/or probability of the human presence detection. If the processor <NUM> decides to activate an infrared light source and the IR LEDs of both lighting device <NUM> and lighting device <NUM> are selected, the processor <NUM> may activate the IR LEDs of both lighting devices at the same time or activate and deactivate each IR LED in sequence.

In the embodiment of the controller <NUM> shown in <FIG>, the controller <NUM> comprises one processor <NUM>. In an alternative embodiment, the controller <NUM> comprises multiple processors. The processor <NUM> of the controller <NUM> may be a general-purpose processor, e.g. ARM-based, or an application-specific processor. The processor <NUM> of the controller <NUM> may run a Unix-based operating system for example. The memory <NUM> may comprise one or more memory units. The memory <NUM> may comprise one or more hard disks and/or solid-state memory, for example.

The receiver <NUM> and the transmitter <NUM> may use one or more wired or wireless communication technologies such as Zigbee to communicate with the lighting devices <NUM>-<NUM> and Ethernet to communicate with the wireless LAN access point <NUM>, for example. In an alternative embodiment, multiple receivers and/or multiple transmitters are used instead of a single receiver and a single transmitter. In the embodiment shown in <FIG>, a separate receiver and a separate transmitter are used. In an alternative embodiment, the receiver <NUM> and the transmitter <NUM> are combined into a transceiver. The controller <NUM> may comprise other components typical for a controller such as a power connector. The invention may be implemented using a computer program running on one or more processors.

A first embodiment of activating an infrared light source is shown in <FIG>. A step <NUM> comprises receiving input indicating human presence in a space, e.g. at night when the lights are off or very low. This may be done by means of a separate presence or motion sensor, or it may be done by presence-detection means integrated into the lighting devices (e.g. integrated microwave sensor, microphone, or RF-based sensing), for example.

A step <NUM> comprises determining an ambient light level. A step <NUM> comprises determining whether the ambient light level LL exceeds a light threshold T. If it is determined in step <NUM> that the ambient light level LL does not exceed the light threshold T, a step <NUM> is performed. If it is determined in step <NUM> that the ambient light level LL exceeds the light threshold T, step <NUM> is repeated and the method then proceeds as shown in <FIG>.

Step <NUM> comprises determining a type and/or probability of the human presence based on the input received in step <NUM>. Next, a step <NUM> comprises deciding whether to activate an infrared light source or a visible-light light source in the space based on the type and/or probability of the human presence determined in step <NUM>. If the decision is made in step <NUM> to activate an infrared light source, a step <NUM> is performed. Step <NUM> comprises activating the infrared light source.

Optionally, a suitable intensity of the individual IR LEDs is determined during the configuration phase. In more advanced unclaimed embodiments, besides presence, also a presence position or movement direction may be determined, and the IR light sources may be controlled according to this position. If the decision is made in step <NUM> to activate a visible-light light source, a step <NUM> is performed. Step <NUM> comprises activating the visible-light light source.

A second embodiment of activating an infrared light source is shown in <FIG>. Step <NUM> comprises receiving input indicating human presence in a space. This may be done by means of a separate presence or motion sensor, or it may be done by presence-detection means integrated into the lighting devices (e.g. integrated microwave sensor, microphone, or RF-based sensing), for example.

Next, a step <NUM> comprises receiving one or more signals from one or more personal mobile devices, if these one or more signals are being transmitted. A personal mobile device may be a smartphone, a wearable device (e.g. a smartwatch), an electronic key, or an electronic vehicle (e.g. an e-bike or a smart car), for example. These one or more signals, if received, comprise one or more user identifications. If it is determined in step <NUM> from the input received in step <NUM> that a human is present, then the one or more user identifications received in step <NUM>, if any, are provided as result of step <NUM>. Optionally, only the user identification(s) received in a signal with a received signal strength exceeding a certain threshold are provided as result.

In the embodiment of <FIG>, step <NUM> of <FIG> is implemented by a step <NUM>. Step <NUM> is performed after step <NUM> and comprises determining the type of the human presence by determining whether the person identification of step <NUM> resulted in a known and/or trusted person being identified, e.g. by comparing an identifier of the detected human with a list of identifiers of known or trusted persons. In the embodiment of <FIG>, the probability of the human presence is not determined.

Next, a step <NUM> comprises deciding whether to activate an infrared light source or a visible-light light source in the space based on the type of the human presence determined in step <NUM>. In the embodiment of <FIG>, it is detected in step <NUM> to activate a visible-light light source when the person the person identification of step <NUM> resulted in a known and/or trusted person being identified and an infrared light source if not.

If the decision is made in step <NUM> to activate an infrared light source, a step <NUM> is performed. Step <NUM> comprises identifying one or more infrared light sources within a certain distance of a device with a camera. For instance, the camera device and the lighting devices may be RF devices and the lighting devices nearby the camera device may be determined based on RSSI. In an alternative unclaimed embodiment, a user is able to explicitly indicate which lighting devices are near the camera device or assign both the lighting devices and the camera device to the same (room) group.

A step <NUM> comprises selecting at least one infrared light source from the one or more infrared light sources. Optionally, the specific type of the light source and/or light fixture may be used to prioritize one light source over the other. Next, step <NUM> comprises activating the infrared light source selected in step <NUM>. If the decision is made in step <NUM> to activate a visible-light light source, a step <NUM> is performed. Step <NUM> comprises activating the visible-light light source. Step <NUM> is repeated after step <NUM> or step <NUM> has been performed and the method then proceeds as shown in <FIG>.

A third embodiment of activating an infrared light source is shown in <FIG>. A step <NUM> comprises obtaining one or more images captured by a camera that is sensitive to infrared wavelengths, e.g. a camera with an infrared filter. A step <NUM> comprises identifying one or more infrared light sources in a field of view of the camera. Infrared light sources which are able to generate a (direct or indirect) effect in the camera's field of view may be determined using coded light (e.g. visible light communication), for example.

For instance, by modulating the visible or infrared light sources of the lighting device, camera-detectable identifiers can be emitted. The modulation may either be active continuously or only during a configuration stage. An advantage of this approach that not only light sources in the direct view of the camera but also those generating their effect in the camera's field of view can be identified. Instead of using coded light, the system can be commissioned during the dark time of the day by switching on and off light sources present in the same area as the camera ("dark room calibration").

Step <NUM> comprises selecting at least one infrared light source from the one or more infrared light sources identified in step <NUM>. In an alternative embodiment, steps similar to steps <NUM>-<NUM> are performed to select at least one visible-light light source.

Step <NUM> comprises receiving input indicating human presence in a space. In the embodiment of <FIG>, step <NUM> is implemented by a step <NUM>. Step <NUM> comprises determining one or more characteristics of a set of received radio frequency signals, i.e. performing RF-based sensing. The one or more characteristics may comprise signal strength and/or Channel State Information (CSI) of the set of received radio frequency signals, for example.

Next, a step <NUM> comprise performing person identification based on the one or more characteristics of the set of received radio frequency signals determined in step <NUM>. Step <NUM> comprises comparing the one or more characteristics of the set of received radio frequency signals, determined in step <NUM>, with one or more of corresponding characteristics of a reference set of radio frequency signals and performing the person identification based on the differences. The differences are used to determine properties of the detected person, e.g. the dimensions of the person, gait of the person and/or route walked by the person. These properties are compared with the properties of known and/or trusted persons, which are associated with person identifiers, and if there is a match, an identifier of the detected person is provided. A calibration procedure typically needs to be performed to establish the gait and usual normal walking routes of a known or trusted person.

Step <NUM> is performed after step <NUM> and comprises determining the type of the human presence by determining whether the person identification of step <NUM> resulted in a known and/or trusted person being identified. In the embodiment of <FIG>, the probability of the human presence is not determined.

Next, a step <NUM> comprises deciding whether to activate the infrared light source(s) or a visible-light light source in the space based on the type of the human presence determined in step <NUM>. In the embodiment of <FIG>, it is decided in step <NUM> to activate a visible-light light source when the person identification of step <NUM> resulted in a known and/or trusted person being identified and to activate the infrared light source(s) if not.

If the decision is made in step <NUM> to activate the infrared light source(s), step <NUM> is performed. Step <NUM> comprises activating the infrared light source(s) selected in step <NUM>. In the embodiment of <FIG>, a step <NUM> is performed next. Step <NUM> comprises activating the camera or a camera function. As a result, the camera device may switch from a standby to operational mode or switches from an energy-saving mode to a normal mode, for example. In an alternative embodiment, the camera continuously records/monitors the space. For example, the camera may continuously record/monitor the space using only its light source(s) and/or external light sources in a dimmed state (e.g. with illumination level enough to detect motion), and after motion is detected, the external IR light sources are activated to full power such that the source of motion is better visible to the camera.

If the decision is made in step <NUM> to activate a visible-light light source, step <NUM> is performed. Step <NUM> comprises activating the visible-light light source. Step <NUM> is repeated after step <NUM> or step <NUM> has been performed and the method then proceeds as shown in <FIG>.

A fourth unclaimed embodiment of activating an infrared light source is shown in <FIG>. Step <NUM> comprises receiving input indicating human presence in a space. In the embodiment of <FIG>, step <NUM> of <FIG> is implemented by a step <NUM>. Step <NUM> is performed after step <NUM> and comprises determining a probability PR of the human presence based on the input received in step <NUM>, e.g. by using RF-based sensing. In the embodiment of <FIG>, a type of the human presence is not determined.

Next, a step <NUM> comprises deciding whether to activate an infrared light source or a visible-light light source in the space based on the probability PR determined in step <NUM>. In the embodiment of <FIG>, step <NUM> is implemented by a step <NUM>. Step <NUM> comprises comparing the probability PR with a first threshold (X%) and a second threshold (Y%) and deciding to activate the infrared light source upon determining that the probability PR exceeds the first threshold (X%) and does not exceed the second threshold (Y%) and deciding to activate the visible-light light source upon determining that the probability PR exceeds the second threshold (Y%).

In a variation on this embodiment, if the visible-light light source is already on, then it is only decided in step <NUM> to deactivate the visible-light light source, e.g. to activate the infrared light source, if the probability has been lower than the second threshold a predetermined amount of time, to prevent frequent activations and deactivations of the visible-light light source.

If the decision is made in step <NUM> to activate an infrared light source, step <NUM> is performed. Step <NUM> comprises activating the infrared light source if not already on and deactivating the visible-light light source if on. If the decision is made in step <NUM> to activate a visible-light light source, step <NUM> is performed. Step <NUM> comprises activating the visible-light light source if not already on and deactivating the infrared light source if on. If it is determined in step <NUM> that the probability PR does not exceed the first threshold (X%), a step <NUM> is performed. Step <NUM> comprises deactivating the infrared light source if it is on and deactivating the visible-light light source if it is on. Step <NUM> is repeated after step <NUM>, step <NUM> or step <NUM> has been performed and the method then proceeds as shown in <FIG>.

A fifth unclaimed embodiment of activating an infrared light source is shown in <FIG>. This fifth embodiment is an extension of the fourth embodiment of <FIG>. A step <NUM> is performed after step <NUM>, i.e. after an infrared light source has been activated. Step <NUM> comprising obtaining infrared camera images from a camera device. The infrared camera images are captured while the infrared light source is emitting light. A step <NUM> comprises performing further human presence detection based on the infrared camera images obtained in step <NUM>. In the embodiment of <FIG>, the result of step <NUM> is binary: either human presence is detected or it is not. In an alternative embodiment, the result of step <NUM> is again a probability.

A step <NUM> comprises deciding whether to activate the visible-light light source based on the further human presence detection performed in step <NUM>. In step <NUM>, it is decided to activate the visible-light light source if the result of step <NUM> is that human presence has been detected. If the decision is made in step <NUM> to activate the visible-light light source, step <NUM> is performed. Step <NUM> comprises activating the visible-light light source. If the decision is made in step <NUM> not to activate the visible-light light source, step <NUM> is repeated and the method proceeds as shown in <FIG>.

In the embodiment of <FIG>, the input may be received from a simple (e.g. single pixel) IR sensor in step <NUM>, for example. The benefit of using simple IR sensing is that it does not consume much energy. If the probability PR determined using simple IR sensing exceeds X% and does not exceed Y%, the infrared light source is activated to allow (IR) camera vision to be used for better presence detection results.

In a variation on this embodiment, step <NUM> is only performed if the visible-light light source is off. If the visible-light light source is already on and the determined probability PR exceeds the first threshold (X%) and does not exceed the second threshold (Y%), the visible-light light source may be kept on.

In a variation on the embodiment of <FIG>, steps <NUM> and <NUM> are omitted, i.e. no further presence detection is performed based on infrared camera images. In this variation, step <NUM> is replaced with a step in which it is determined how long on end presence has been detected and if presence is still detected after some predefined time duration (e.g. the probability PR determined in step <NUM> exceeds X% and does not exceed Y% in a predefined number of successive iterations), step <NUM> is performed. If presence has not been detected for the predefined time duration yet, step <NUM> is repeated.

The embodiments of <FIG> differ from each other in multiple aspects, i.e. multiple steps have been added or replaced. In variations on these embodiments, only a subset of these steps is added or replaced and/or one or more steps is omitted. For example, steps <NUM> and <NUM> may be omitted from the embodiment of <FIG> and/or added to the embodiments of <FIG> and/or the embodiments of <FIG> and <FIG> may each be combined with the embodiment of <FIG> or <FIG>.

<FIG> depicts a block diagram illustrating an exemplary data processing system that may perform the method as described with reference to <FIG>.

<FIG> shows the input device <NUM> and the output device <NUM> as being separate from the network adapter <NUM>. However, additionally or alternatively, input may be received via the network adapter <NUM> and output be transmitted via the network adapter <NUM>. For example, the data processing system <NUM> may be a cloud server. In this case, the input may be received from and the output may be transmitted to a user device that acts as a terminal.

Claim 1:
A system (<NUM>,<NUM>) for activating an infrared light source (<NUM>) or a visible-light light source (<NUM>), said system (<NUM>,<NUM>) comprising:
at least one input interface (<NUM>,<NUM>);
at least one control interface (<NUM>,<NUM>); and
at least one processor (<NUM>,<NUM>) configured to:
- receive, via said at least one input interface (<NUM>,<NUM>), input indicating human presence in a space,
- perform person identification based on said input and/or based on further input,
- determine a type of said human presence based on said input by determining whether said person identification resulted in a known and/or trusted person being identified,
- decide whether to activate an infrared light source (<NUM>) or a visible-light light source (<NUM>) in said space based on said type of said human presence, and
- activate, via said at least one control interface (<NUM>,<NUM>), said infrared light source (<NUM>) or said visible-light light source (<NUM>) in dependence on said decision.