阅读说明：本技术 基于感测到的距离来确定用户存在 (determining user presence based on sensed distance ) 是由 S·S·阿扎姆 W·S·陈 C·C·莫尔曼 于 2017-07-25 设计创作，主要内容包括：一种方法包括利用传感器感测用户到计算设备的显示器的距离。所述方法还包括：利用计算设备对感测到的距离与阈值距离进行比较；以及利用计算设备至少部分地基于所述比较来确定用户是否存在于显示器处。(A method includes sensing, with a sensor, a distance of a user from a display of a computing device. The method further comprises the following steps: comparing, with the computing device, the sensed distance to a threshold distance; and determining, with the computing device, whether the user is present at the display based at least in part on the comparison.)

1. A method, comprising:

Sensing, with a sensor, a distance of a user from a display of a computing device;

Comparing, with the computing device, the sensed distance to a threshold distance; and

Determining, with the computing device, whether the user is present at the display based at least in part on the comparison.

2. the method of claim 1, and further comprising:

reporting, with the sensor, the sensed distance to the computing device; and

Reporting, with the sensor, a Boolean value to the computing device, the Boolean value indicating whether the user is present within a field of view of the sensor.

3. The method of claim 1, and further comprising:

causing the brightness of the display to automatically decrease when the computing device determines that the user is not present at the display.

4. The method of claim 3, wherein the brightness of the display immediately decreases to a dark state when it is determined by the computing device that the user is not present at the display.

5. The method of claim 3, wherein the brightness of the display is reduced in stages to a dark state when it is determined by the computing device that the user is not present at the display.

6. The method of claim 1, and further comprising:

Causing the computing device to be locked when the computing device determines that the user is not present at the display.

7. the method of claim 6, and further comprising:

Triggering a user authentication process after the computing device is locked when the computing device determines that the user is present at the display.

8. The method of claim 7, wherein the user authentication process is an automatic authentication process using a camera for facial recognition.

9. The method of claim 7, wherein the user authentication process is an automatic authentication process using bluetooth authentication.

10. a system, comprising:

A computing device comprising a display;

A sensor for sensing a distance of a user to the display; and

at least one processor in the computing device to:

Comparing the sensed distance to a threshold distance; and

Determining whether the user is present at the display based at least in part on the comparison.

11. The system of claim 10, wherein the sensor comprises a plurality of time-of-flight (ToF) sensors each sensing a distance of the user from the display.

12. The system of claim 11, wherein at least one of the ToF sensors is a multi-zone ToF sensor that includes an array of zones and determines a separate distance value for each of the zones.

13. The system of claim 10, wherein the sensor comprises a lower power state and a higher power state, and wherein the sensor checks for the presence of the user more frequently in the higher power state than in the lower power state.

14. a non-transitory computer-readable storage medium storing instructions that, when executed by at least one processor, cause the at least one processor to:

Receiving, from a sensor, a distance value representing a distance of a user from a display of a computing device and a Boolean value indicating whether the user is present within a field of view of the sensor; and

Determining whether the user is present at the display based on the received distance value and the received Boolean value.

15. The non-transitory computer-readable storage medium of claim 14, and further storing instructions that, when executed by the at least one processor, cause the at least one processor to:

Decreasing the brightness of the display when it is determined that the user is not present at the display.

Background

modern operating systems provide a comprehensive approach to system and device power management. Timer-based features may be used to provide power savings. For example, if the time of lack of user activity exceeds the time of the IT idle timer policy, the system provides for entering a low power state to begin saving power. When the IT policy threshold is reached, power saving begins.

Drawings

FIG. 1 is a diagram illustrating a computing device with presence detection capabilities, according to one example.

FIG. 2 is a block diagram illustrating elements of the computing device shown in FIG. 1, according to one example.

Fig. 3A-3C are diagrams illustrating exemplary presence sensor configurations.

FIG. 4 is a flow diagram illustrating a method for detecting user presence according to one example.

Detailed Description

In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific examples in which the disclosure may be practiced. It is to be understood that other examples may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims. It should be understood that features of the various examples described herein may be combined with each other, in part or in whole, unless specifically noted otherwise.

Timer-based latching for displays is a privacy issue and may waste host system resources. Most Information Technology (IT) policies set the idle timer to a 10-20 minute range. If the lack of user activity is outside the IT idle timer policy, the system begins to save power by entering a lower power state. When the IT policy threshold is reached, power saving begins. The savings are minimal in the case where the user resumes normal activity immediately after reaching the IT idle threshold. This approach, which relies on IT-defined policies, may work when the user is idle for a longer time, but IT has drawbacks because the device may still be wasting power during the first time period when the IT threshold timer is not reached. Also, IT policies that require the user not to turn the display on and unattended are difficult to implement.

Some examples disclosed herein relate to using a presence sensor to detect the presence of a user to control backlighting of a display, and to initiate user authentication (e.g., login/logoff) on a host computing device. In some examples, a time-of-flight (ToF) sensor determines a distance of a user from a display. Some examples use multiple ToF sensors. In other examples, another type of sensor capable of measuring the distance of the user to the display may be used. A user authentication process (e.g., a login process) is automatically triggered when one or more sensors detect that a user has just approached the display. When one or more sensors detect that the user has left the display, the brightness of the display is immediately or gradually reduced to a dark or off state. By automatically dimming the screen and initiating logout and login using the ToF sensor, productivity is automatically improved, power savings are increased, and the life of the display backlight is extended.

Fig. 1 is a diagram illustrating a computing device 104 with presence detection capabilities, according to one example. In the illustrated example, the presence sensor 106 is positioned on the display 105 of the computing device 104 or in close proximity to the display 105 of the computing device 104. The sensors 106 may be connected to the computing device 104 via USB, or may be connected directly to the device 104 using a sensor hub. In some examples, the presence sensor 106 includes a ToF sensor or another type of sensor that determines the distance 101 of the user 102 from the display 105. In some examples, the presence sensor 106 also generates a boolean value indicating whether the user 102 is currently present within the range and field of view (FOV) of the sensor 106. The presence sensor 106 may be a multi-zone ToF sensor that includes an array of zones (e.g., 2x2, 3x3, 4x4, or a user-defined array) and determines individual distance values for each individual zone. In some examples, an on-screen display (OSD) menu may be used in display 105 to disable and enable the presence detection feature and to select an option for the presence detection feature.

FIG. 2 is a block diagram illustrating elements of the computing device 104 shown in FIG. 1, according to one example. The computing device 104 includes at least one processor 202, memory 204, input device 220, output device 222, display 105, and presence sensor 106. In the example shown, the processor 202, memory 204, input device 220, output device 222, display 105, and presence sensor 106 are communicatively coupled to each other by a communication link 218. The presence sensor 106 may be embedded within the frame of the display 105, mounted along at least one edge of the display 105, or mounted in a suitable location in the space in which the display 105 is located.

Input devices 220 include a keyboard, mouse, data port, and/or other suitable device for inputting information into device 104. Output device 222 includes a speaker, a data port, and/or other suitable device for outputting information from device 104.

processor 202 includes a Central Processing Unit (CPU) or another suitable processor. In one example, the memory 204 stores machine-readable instructions for execution by the processor 202 for operating the device 104. The memory 204 includes any suitable combination of volatile and/or nonvolatile memory such as a combination of Random Access Memory (RAM), Read Only Memory (ROM), flash memory, and/or other suitable memory. These are examples of non-transitory computer-readable storage media. The memory 204 is non-transitory in the sense that it does not contain transitory signals, but rather is comprised of at least one memory component to store machine executable instructions for performing the techniques described herein.

The memory 204 stores a sensor data processing module 206, a user authentication module 208, and a display control module 210. Processor 202 executes instructions of modules 206, 208, and 210 to perform the techniques described herein. Note that some or all of the functionality of modules 206, 208, and 210 may be implemented using cloud computing resources.

In examples using multiple ToF sensors 106, the individual ToF sensors may be enumerated separately, and each sensor 106 reports to the computing device 104 the presence detection boolean value and the distance value at predefined time intervals. In one example, the boolean value and the distance value are provided to the sensor data processing module 206 for processing. For the example using multiple ToF sensors 106, the sensor data processing module 206 may assume that the user 102 is present as long as the presence detection boolean value of at least one of the sensors 106 indicates that the user 102 is present, and may assume that the user 102 is no longer present when the presence detection boolean values of all of the sensors 106 indicate that the user 102 is not present. For the example using a single ToF sensor 106, the sensor data processing module 206 may assume that the user 102 is present as long as the presence detection boolean value of the single sensor 106 indicates that the user 102 is present, and may assume that the user 102 is no longer present when the presence detection boolean value of the single sensor 106 indicates that the user is not present.

Even in the event that the presence detection boolean value from the sensor 106 indicates the presence of the user 102, the sensor data processing module 206 may conclude that the user 102 is not present based on the distance data. The sensor data processing module 206 compares the distance data received from the sensor 106 to the existing distance threshold. If the received distance value is less than the threshold, then the module 206 may assume that the user 102 is present. If the received distance value is greater than the threshold, module 206 may assume that user 102 is not present. In some examples, the presence distance threshold may be defined by the user 102 (e.g., via an OSD menu of the display 105).

In some examples, when the user 102 is proximate to the computing device 104 while the device 104 is in a low power state (e.g., a sleep state), the sensor 106 will detect the presence of the user 102, which triggers the automatic initiation of a user identity authentication process (e.g., a manual login process using a personal identification number/password, or an automatic process with Bluetooth (BT) authentication or automatically triggering a camera for facial recognition). BT authentication may use the user's 102 handset as an authentication token, such that if the user 102 is detected to be present and his or her handset is in close proximity, the user 102 is automatically authenticated. When the sensor data processing module 206 determines that the user 102 previously did not exist and is now currently present based on the received sensor data, the module 206 signals the display control module 210 to increase the brightness of the display 105 and cause the computing device 104 to wake up from the low power state. Module 206 also signals user authentication module 208 to begin the user authentication process.

for a user leaving the scene, the response may be user defined (e.g., via an OSD menu of display 105) to cause the brightness of display 105 to immediately or step down to a dark or off state. For the immediate decrease case, the sensor 106 will detect the absence of the user 102 and report this information to the sensor data processing module 206. The sensor data processing module 206 then notifies the display control module 210 that the user is not present. In response, the display control module 210 causes the display 105 to immediately dim. Display control module 210 also generates a lock signal that causes computing device 104 to be locked (i.e., locked such that user authentication will be subsequently triggered to unlock device 104) and causes computing device 104 to enter a low power state.

For the step-by-step case, the brightness of display 105 is reduced in stages, according to some examples. In the first phase, after the user 102 is absent for more than a first period of time (e.g., 10 seconds), the display control module 210 reduces the display brightness by 30% from the last user setting (note that the user setting may have been a reduced level). In the second phase, after the user 102 is absent for more than a second period of time (e.g., 20 seconds in total), the display control module 210 reduces the display brightness by another 20%. If the user 102 returns to the computing device 104 (prior to the third stage) and is sensed as present, the display control module 210 gradually increases the display brightness in increments (e.g., 5% increments every quarter second) without further authentication until the full brightness level is restored.

in the third phase, after the user 102 is absent for a third period of time (e.g., X seconds, where X is an integer greater than 20), the display control module 210 gradually decreases the display brightness by another X% until a maximum decrease in display brightness has been achieved. At this point, the display control module 210 generates a lock signal to lock the computing device 104. If the user 102 returns and is perceived as present before the maximum brightness reduction is reached, the display control module 210 gradually increases the display brightness in increments (e.g., 5% increments every quarter second) without further authentication until the full brightness level is restored. If the user 102 does not return before the maximum brightness reduction is reached and the device 104 has been locked, then a restart of the user's presence at this time will trigger the authentication process.

In some examples, the computing device 104 uses multiple distance thresholds and changes the dimming rate of the display 105 based on the multiple thresholds. For example, if the user 102 is sensed to exceed a first distance threshold, which is the shortest distance threshold, the display control module 210 may dim the display 105 at a first rate, which may be the slowest dimming rate. If the user 102 is sensed to exceed the second distance threshold, which is a longer distance than the first distance threshold, the display control module 210 may dim the display 105 at a second rate, which may be faster than the first rate. If it is sensed that the user 102 is no longer present (e.g., it is sensed that the user 102 exceeds the present distance threshold, which is a longer distance than the second distance threshold), the display control module 210 may dim the display 105 at a third rate, which may be faster than the second rate.

In some examples, the distance threshold may vary based on the lateral position of the user 102 relative to the display 105. For example, the distance thresholds for locations on the left and right sides of display 105 may be the same, but may be different than the distance thresholds for locations near the center of display 105. In one example, the display control module 210 may dim the display 105 when the user 102 just exceeds the edge of the display 105, but may use a higher distance threshold when the user 102 is near the center of the display 105. Further, each different location (e.g., left, center, right) with respect to the display 105 may have multiple distance thresholds, and the distance thresholds and dimming rates may vary from location to location.

In some examples, the computing device 104 generates an audible and/or visual warning signal when the user 102 is detected to be too close to the display of the computing device 104. In particular, if the sensor data processing module 206 determines that the distance value provided by the sensor 106 is less than a threshold value (e.g., 50mm), the module 206 causes at least one of the display 105 and/or the output device 222 to generate a warning signal. This feature may provide protection for the user's eyes, which may be damaged by prolonged exposure at close distances. The sensor data processing module 206 may also track the length of time the user 102 has been present in front of the display 105 and cause an audible and/or visual warning signal to be generated when the time exceeds a predetermined threshold.

In some examples, the sensor data processing module 206 causes the distance values received from the sensors 106 to be displayed on the display 105. For example, the displayed information may be used to assist the user in moving to an appropriate distance for facial recognition. In some examples, based on the distance value received from the sensor 106, the sensor data processing module 206 causes an adjustment to be made to at least one of the input device 220 and the output device 222 (e.g., adjustments to the speaker and microphone of the device 104 based on the sensed distance of the user 102). Such adjustments may include, for example, changing the mode of the devices, increasing the volume as the user 102 moves away from the device 104, and/or decreasing the volume as the user 102 moves closer to the device 104. In some examples, based on the distance values received from the sensors 106, the sensor data processing module 206 causes a change to the display characteristics of the display 105 (e.g., increasing the font size as the user 102 moves away from the display 105 and decreasing the font size as the user moves closer to the display 105). The sensor 106 may also be used to detect gestures (e.g., tap gestures or swipe gestures) made by the user 102, and the sensor data processing module 206 may cause actions to be performed based on the detected gestures.

In some examples, the sensor 106 includes a lower power mode and a higher power mode. In the lower power mode, the sensor 106 uses less power and checks for the presence of the user 102 less frequently than in the higher power mode. In some examples, when the sensor 106 detects the presence of the user 102, the sensor 106 operates in a lower power mode, and when the sensor 106 detects that the user 102 is no longer present, the sensor 106 is automatically switched to a higher power mode to check for the presence of the user 102 more frequently.

fig. 3A-3C are diagrams illustrating exemplary presence sensor configurations. As shown in fig. 3A, display 105(1) includes a single presence sensor (e.g., ToF sensor) 106 (1). The presence sensor 106(1) has a field of view (FOV)302(1) of approximately 27 degrees. The center line of the FOV 302(1) is perpendicular or substantially perpendicular to the display 105 (1). The user 102 is positioned at a distance 304(1) of about 60cm from the display 105 (1). The FOV 302(1) has a lateral length 306(1) of about 29cm at this distance (and correspondingly, the laterally detectable range of the user 102). As shown in fig. 3B and 3C, the laterally detectable range may be increased by using multiple presence sensors 106.

As shown in fig. 3B, display 105(2) includes two presence sensors (e.g., ToF sensors) 106(2) and 106(3) that are positioned a distance 310(1) of about 29cm apart. Presence sensors 106(2) and 106(3) have FOV 302(2) and FOV 302(3), respectively, which are both about 27 degrees. The center lines of the FOVs 302(2) and 302(3) are perpendicular or substantially perpendicular to the display 105 (2). The user 102 is positioned at a distance 304(2) of about 60cm from the display 105 (2). The combined FOVs 302(2) and 302(3) have a transverse length 306(2) at this distance (and correspondingly, the transverse detectable range of the user 102) of about 58 cm. Between the FOVs 302(2) and 302(3) of the two presence sensors 106(2) and 106(3), there is a blind zone 308(1) extending outward from the display 105(2), where the presence of the user 102 is undetectable. As shown in fig. 3C, the size of the blind spot can be reduced by adjusting the angle of the sensor 106.

As shown in fig. 3C, display 105(3) includes two presence sensors (e.g., ToF sensors) 106(4) and 106(5) that are positioned a distance 310(2) of about 10cm apart. Presence sensors 106(4) and 106(5) have FOV 302(4) and FOV 302(5), respectively, which are both about 27 degrees. The center lines of the FOVs 302(4) and 302(5) are perpendicular or substantially perpendicular to the display 105 (3). The user 102 is positioned at a distance 304(3) of about 60cm from the display 105 (3). The combined FOVs 302(4) and 302(5) have a transverse length 306(3) of about 58cm at this distance (and correspondingly, the transverse detectable range of the user 102). Between the FOVs 302(4) and 302(5) of the two presence sensors 106(4) and 106(5), there is a blind zone 308(2) extending outward from the display 105(3), where the presence of the user 102 is undetectable. By reducing the distance 310 between the sensors 106 and tilting the sensors 106 outward, as shown in fig. 3C, the size of the dead zone 308(2) is reduced compared to the size of the dead zone 308(1) shown in fig. 3B, while still providing the same laterally detectable range.

The use of multiple presence sensors 106 with distance detection helps the system distinguish between people and non-people (e.g., chairs or coffee cups) and provides more accurate tracking of the user 102, including being able to determine the direction in which the user 102 has moved away from the display 105 (e.g., whether the user has exited the left side of the display or the right side of the display). Some examples determine whether an object is moving based on the distance of the object sensed over time, which helps the system to distinguish between human and non-human objects.

One example is directed to a method for detecting user presence. Fig. 4 is a flow diagram illustrating a method 400 for detecting user presence according to one example. In one example, the computing device 104 (fig. 1) may perform the method 400. At 402 in method 400, a sensor senses a distance of a user from a display of a computing device. At 404, the computing device compares the sensed distance to a threshold distance. At 406, the computing device determines whether a user is present at the display based at least in part on the comparison.

In some examples, method 400 may further include reporting, with the sensor, the sensed distance to the computing device; and reporting, with the sensor, a boolean value to the computing device, the boolean value indicating whether the user is within a field of view of the sensor. The method 400 may further include: when the computing device determines that the user is not present at the display, an automatic reduction in brightness of the display is caused. When the computing device determines that the user is not present at the display, the brightness of the display may immediately decrease to a dark state. When the computing device determines that a user is not present at the display, the brightness of the display may be gradually reduced to a dark state in stages.

In some examples, the method 400 may further include: the computing device is caused to be locked when the computing device determines that the user is not present at the display. The method 400 may also include triggering a user authentication process after the computing device is locked when the computing device determines that a user is present at the display. The user authentication process may be an automatic authentication process using a camera for face recognition. The user authentication process may be an automatic authentication process using bluetooth authentication.

Another example relates to a system, comprising: a computing device including a display; and a sensor that senses a distance of the user from the display. The system also includes at least one processor in the computing device to: comparing the sensed distance to a threshold distance; and determining whether a user is present at the display based at least in part on the comparison.

In some examples, the sensor may include a plurality of time-of-flight (ToF) sensors that each sense a distance of the user from the display. At least one of the ToF sensors may be a multi-region ToF sensor that includes an array of regions and determines individual distance values for each region. The sensor may include a lower power state and a higher power state, and wherein the sensor checks for the presence of the user more frequently in the higher power state than in the lower power state.

Another example is directed to a non-transitory computer-readable storage medium storing instructions that, when executed by at least one processor, cause the at least one processor to: receiving, from a sensor, a distance value representing a distance of a user from a display of a computing device and a Boolean value indicating whether the user is present within a field of view of the sensor; and determining whether a user is present at the display based on the received distance value and the received boolean value.

The non-transitory computer-readable storage medium may also store instructions that, when executed by the at least one processor, cause the at least one processor to: when it is determined that the user is not present at the display, the brightness of the display is reduced.

Although specific examples have been illustrated and described herein, various alternative and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.