Patent Application
20250046230
The present invention generally relates to a method for adjusting brightness of an electronic visual display, and in particular to brightness control of an electronic visual display used in a security system.
An electronic visual display is a display apparatus for presentation of any visual content e.g., texts, images or videos, which is transmitted electronically. Among various different electronic visual displays, light-emitting diode (LED) displays and liquid-crystal displays (LCDs) are the two most widely used types of displays. Electronic visual displays have become ubiquitous in people's daily lives. This is evidenced by the fact that electronic visual displays are present in almost all household electrical appliances (e.g., air conditioners, microwave ovens, home security systems) and consumer electronics (e.g., laptops, television sets, mobile computing devices). At present, many electronic visual displays, in particular LED displays and LCDs, have incorporated technologies that allow their brightness to be dynamically adjusted in response to a change in brightness of their ambient light, e.g., the brightness of a display is increased when the ambient environment gets brighter, or decreased when the ambient environment gets darker.
In an existing home or business security system, a control panel is used to communicate with a number of sensors via a wired or wireless path and to provide a user interface between the human user and the security system so as to allow the user to arm and disarm the system. The control panel often comprises an electronic visual display (e.g., a LED display and/or a LCD) for displaying present status of the security system and a keypad for allowing the user to enter or change settings of the system. The brightness of the control panel display may be automatically adjusted (e.g., dimed) when the control panel detects a change (e.g., darkening) in the surrounding light level.
Such an automatic brightness control typically relies on use of one or more ambient light sensors dedicated to monitor the ambient light level, which adds complexity and costs to the security system. In some existing implementations, the ambient light sensors constantly monitor a given space (e.g., a room) in which the control panel is installed (e.g., on a wall of the room) and output a luminance value which corresponds to either a total/accumulated light level or an average light level of the monitored space. Subsequently, the control panel adjusts the brightness of the display according to the total/average luminance value.
The aforementioned brightness control method may be capable of accurately determining a desired display brightness where the light is homogeneously distributed across the monitored space. However, in cases where the light is in-homogeneously distributed across the monitored space (e.g., when localized artificial light is present), the accuracy of the brightness control will be negatively impacted. By way of an example, where localized artificial light is present in the monitored space, it can result in a significantly increased total/average luminance value of the monitored space whereas in the meantime the ambient light level of the area (e.g., a corner of a room) that is immediately adjacent to the control panel stays substantially unchanged. In such a situation, the brightness of the control panel display will be undesirably increased in response to an increased total/average luminance value as a result of the presence of the artificial light. Inaccurate brightness control of a control panel display can not only give a bad user experience but also cause issues when the user finds the information on the display unreadable.
Objects and aspects of the present claimed invention seek to alleviate at least these problems with the prior art.
According to a first aspect of the present invention, there is provided a method for adjusting brightness of an electronic visual display of an electronic device, comprising: identifying a luminance-indicating area in a field of view of an image sensor of the electronic device; capturing at least one first image of the field of view by the image sensor; determining an ambient luminance value for the electronic visual display using the luminance-indicating area of the at least one first image; and adjusting the brightness of the electronic visual display according to the determined ambient luminance value; wherein the step of identifying the luminance-indicating area in the field of view of the image sensor comprises: capturing a plurality of second images of the field of view of the image sensor, each second image being taken at a different time of a day, and analyzing the plurality of second images so as to identify an area of the field of view of the image sensor which has the most stable average luminance level.
In an embodiment, the plurality of second images of the field of view are each taken at a predetermined time interval. Alternatively or in addition, the plurality of second images of the field of view are taken respectively at a plurality of predetermined times.
In an embodiment, the step of determining the ambient luminance value for the electronic visual display comprises obtaining a luminance value for each pixel of the luminance-indicating area of the at least one first image. In an embodiment, the step of determining the ambient luminance value for the electronic visual display further comprises obtaining the ambient luminance value by taking an average of the luminance values of all pixels of the luminance-indicating area of the at least one first image.
In an embodiment, the step of adjusting the brightness of the electronic visual display comprises comparing the ambient luminance value determined for the electronic visual display with a reference luminance value or a reference luminance table.
In an embodiment, the step of adjusting the brightness of the electronic visual display further comprises decreasing the brightness of the electronic visual display to a level corresponding to the ambient luminance value when the ambient luminance value is lower than the reference luminance value. In an embodiment, the step of adjusting the brightness of the electronic visual display further comprises increasing the brightness of the electronic visual display to a level corresponding to the ambient luminance value when the ambient luminance value is higher than the reference luminance value. In an embodiment, the step of adjusting the brightness of the electronic visual display further comprises maintaining the brightness of the electronic visual display when the ambient luminance value is equal to the reference luminance value. In an embodiment, the reference luminance value is a previous ambient luminance value determined based on one or more previously captured first images.
In an embodiment, the reference luminance table comprises a plurality of reference luminance ranges, each range corresponding to a specific brightness level. In an embodiment, the step of adjusting the brightness of the electronic visual display further comprises determining a target brightness by identifying which reference luminance range the ambient luminance value falls into. In an embodiment, the step of adjusting the brightness of the electronic visual display further comprises adjusting the brightness of the display to the target brightness.
In an embodiment, the electronic device is a security control panel of a security system. In an embodiment, the method further comprises turning off the electronic visual display when the security system is in an armed state. In an embodiment, the step of capturing the at least one first image of the field of view by the image sensor is performed at a predetermined time interval when the security system is in a disarmed state.
In an embodiment, the electronic visual display comprise one or both of: a liquid crystal display; a light-emitting diode display.
According to a second aspect of the present invention, there is provided a computer program comprising program instructions operable to perform the method of the first aspect, when run on a suitable apparatus.
According to a third aspect of the present invention, there is provided a non-transient computer program carrier comprising the computer program of the second aspect.
According to a fourth aspect of the present invention, there is provided an electronic device, comprising: an image sensor having a field of view and configured to take images; an electronic visual display; a memory unit storing a computer program comprising program instructions for adjusting brightness of the electronic visual display; and a processing unit; wherein upon executing the computer program, the processing unit is to: identify a luminance-indicating area in the field of view of the image sensor; command the image sensor to capture at least one first image of the field of view; determine an ambient luminance value for the electronic visual display using the luminance-indicating area of the at least a first image; and adjust the brightness of the electronic visual display according to the determined ambient luminance value; wherein at the step of identifying the luminance-indicating area in the field of view of the image sensor, the processing unit is further to: command the image sensor to capture a plurality of second images of the field of view of the image sensor, each second image being taken at a different time of a day, and analyze the plurality of second images of the field of view so as to identify an area of the field of view of the image sensor which has the most stable average luminance level.
In an embodiment, the electronic visual display comprises one or both of: a liquid crystal display; a light-emitting diode display.
According to a different aspect of the present invention, there is provided a security system comprising an electronic device of the fourth aspect.
Other aspects of the invention comprise a security system comprising the electronic device of the second aspect.
Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:
With reference to
The sensors 180a-180f may be of any type of sensors commonly used in a home or business security system, which may include for example, one or more motion sensors 180a for detecting when a person enters a room, one or more fire sensors 180b for indicating that a fire has been detected, one or more window 180c and door sensors 180d for indicating that a window or door has been opened, and/or one or more shock sensors 180e for detecting a shock that occurs when a burglar strikes the door or window with a hard object. Different and/or additional sensors 180f may be provided.
The control panel 110 may be configured to receive, process and transmit signals. To provide such functionalities, the control panel 110 may comprise a processing unit 130 (e.g., a microprocessor) for processing information (e.g., signals received from the components of the security system 100 and the remote server 190 where available), a memory unit 140 (e.g., non-transient memory) for storing data (e.g., system information and control programs), a power unit 150 for powering the components of the control panel 110, and a communication unit 160 (e.g., a transceiver) for receiving signals from and transmitting signals to the components of the security system 100 and the remote server where available.
The control panel 110 may further be configured to provide a user interface between the human user and the security system 100. As can be seen in
In an embodiment, the user interface unit 120 may be comprised in a separate user interface device that is located differently to the control panel 110 and is communicatively coupled to the control panel 110 via a wired or wireless path. The separate user interface device may comprise same or similar components as the control panel 110, e.g., a processing unit, a memory, a power unit and a communication unit. In an embodiment, the key pad 126 may be provided by a touch screen which is an integral part of the display 122.
With reference to
With reference to
In step 310, the processing unit 130 may identify a luminance-indicating area (e.g., zone Z3) in the field of view (e.g., as shown in
Note that in contrast to existing technologies (e.g., as described above) where one or more dedicated image sensors are required for monitoring the ambient light level, the brightness control program 300 can be implemented with an existing built-in image sensor that is already present in the control panel 110 and originally configured to carry out tasks other than monitoring of the ambient light level. Such tasks may include for example capturing pictures of a user when the user intends to operate the control panel 110 (e.g., to arm or disarm the security system 100) so as to verify authorization for the intended operation and/or keep the pictures of the (unauthorized) user as evidence for later use; and recording videos when the control panel 110 receives an alarm signal generated by any of the sensors 180a-180f.
In step 320, the processing unit 130 may command the image sensor 122 to capture at least one image of the field of view. In an embodiment, images may be captured in a periodical manner, i.e. at a predetermined time interval. For example, the image sensor 122 may capture at least one image per every one hour, at least one image per every two hours, or at least one image per every three hours. Once an image or images is/are captured, the processing unit 130 may continue to progress to step 330.
In step 330, the processing unit 130 may determine an ambient luminance value for the display 124 based on the luminance-indicating area of the image or images captured in step 320. Where two or more images are captured consecutively (e.g., within the predetermined time interval), each image may be used to determine an ambient luminance value and all the determined ambient luminance values may be averaged to determine a final ambient luminance value. The ambient luminance value is able to indicate the ambient light level around the control panel 110 in a more accurate manner and thus allows for a more accurate and reliable brightness control. In an embodiment, the processing unit 130 may first obtain a luminance value for each pixel of the luminance-indicating area of the image and then determine the ambient luminance value by taking an average of the luminance values of all pixels of the luminance-indicating area of the image. Note that the ambient luminance value may be determined in many different ways. For example, in an embodiment, the ambient luminance value may be determined by calculating a weighted arithmetic mean of the luminance values of all pixels of the luminance-indicating area of the image. In an embodiment, the ambient luminance value may be determined by analyzing the luminance histogram of the luminance-indicating area of the image.
In step 340, the processing unit 130 may adjust a brightness level of the display 124 according to the ambient luminance value determined in step 330. In an embodiment, the processing unit 130 may compare the ambient luminance value determined in step 330 with a reference luminance value. In an embodiment, the reference luminance value may be a previously determined ambient luminance value based on a previously captured image. In an embodiment, when the ambient luminance value determined in step 330 is less than the reference luminance value, the processing unit 130 may decrease the brightness level of the display 124 to a level corresponding to the ambient luminance value determined in step 330. In an embodiment, when the ambient luminance value determined in step 330 is more than the reference luminance value, the processing unit 130 may increase the brightness level of the display 124 to a level corresponding to the ambient luminance value determined in step 330. In an embodiment, the processing unit 130 may maintain the brightness level of the display 124 when the ambient luminance value determined in step 330 is equal to the reference luminance value.
In different embodiments, the memory unit 140 may store a look up table (or reference luminance table) which may comprise a plurality of reference luminance ranges, each of which may comprise a starting reference luminance value and an ending reference luminance value and each of which may correspond to a specific brightness level of the display 124. In operation, the processing unit 130 may first compare the ambient luminance value determined in step 330 against each range of the reference luminance table. The processing unit 130 may then determine a target brightness for the display 124 after identifying which reference luminance range the ambient luminance value falls into. The processing unit 130 may adjust the brightness of the display 124 to the target brightness.
In cases where the electronic visual display 124 comprises a LCD, the brightness of the display 124 may be adjusted through adjustment of the backlight (e.g., LED backlight) intensity. In cases where the electronic visual display 124 comprises a LED display, the brightness of the display 124 may be adjusted through direct adjustment of the LED intensity.
Optionally or in addition, the brightness control program 300, when executed, may cause the processing unit 130 to perform further steps. For example, the processing unit 130 may turn off the display 124 when the security system 100 is in an armed state. The processing unit 130 may command the image sensor 122 to capture an image at a predetermined time interval when the security system 100 is in a disarmed state. When the user sets the security system 100 to the disarmed state, the processing unit 130 may command the image sensor 122 to capture an image of the user, as described above.
With reference to
In step 410, the processing unit 130 may command the image sensor 122 to take a plurality of images of the field of view of the image sensor. Each image may be taken at a different time of a day. For example, with reference to
In step 420, the processing unit 130 may analyze the plurality of images of the field of view (e.g., the images shown in
Note that the images shown in
In step 430, storing the positional information of the area identified in step 420 in the memory unit 140. Such positional information may be requested by the brightness control program 300, as described above.
Note that, despite the foregoing embodiments are described in connection with a security system, the method is equally applicable for automatic and accurate brightness control of an electronic visual display comprised in other different electronic devices or systems. Note that, the above description is for illustration only and other embodiments and variations may be envisaged without departing from the scope of the invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2021/073081 | 12/22/2021 | WO |
