Presence sensing

Abstract

One embodiment may take the form of a method of operating a computing device to provide presence based functionality. The method may include operating the computing device in a reduced power state and collecting a first set of data from a first sensor. Based on the first set of data, the computing device determines if an object is within a threshold distance of the computing device and, if the object is within the threshold distance, the device activates a secondary sensor to collect a second set of data. Based on the second set of data, the device determines if the object is a person. If the object is a person, the device determines a position of the person relative to the computing device and executes a change of state in the computing device based on the position of the person relative to the computing device. If the object is not a person, the computing device remains in a reduced power state.

1 . A method of operating a computing device to provide presence based functionality, the method comprising:
 operating the computing device in a reduced power state;   collecting a first set of data from a first sensor;   determining, based on the first set of data, if an object is within a threshold distance of the computing device;   if the object is within the threshold distance, activating a secondary sensor to collect a second set of data;   determining, based on the second set of data, if the object is a person;
 if the object is a person: 
 determining a position of the person relative to the computing device; and 
 executing a change of state in the computing device based on the position of the person relative to the computing device; and 
   if the object is not a person, maintaining the computing device in a reduced power state.   
     
     
         2 . The method of  claim 1  further comprising operating the first sensor in a time division multiplexed manner. 
     
     
         3 . The method of  claim 1  further comprising using multiple light sources covering discrete/different fields of view. 
     
     
         4 . The method of  claim 1  further comprising changing modulation frequencies if multiple sensors are in the same room. 
     
     
         5 . The method of  claim 1  wherein making a change in state comprises at least one of:
 changing a display background/screen saver shift, wherein the shift corresponds to movement of the user; 
 bringing the display to an awake state; 
 bringing the system to an awake state; 
 reducing a number of processes when bringing the system to an awake state; 
 audio steering based on position of user; 
 microphone steering based on user position; and 
 modifying the user interface so that if the user is far away a smaller set of user options are provided. 
 
     
     
         6 . The method of  claim 5  wherein if the system is already awake and detects that the user moves away from the system, the system is configured to:
 change display state to a sleep state; or 
 change system state to a sleep state. 
 
     
     
         7 . The method of  claim 1  further comprising using combined sensor data to determine presence using a neural net or a support vector machine. 
     
     
         8 . The method of  claim 1  further comprising using combined sensor data to determine presence using a probabilistic determination. 
     
     
         9 . The method of  claim 1  further comprising using combined sensor data to determine presence using each of a skin tone determination, a presence determination, and a movement determination in a weighted manner to make the presence determination. 
     
     
         10 . The method of  claim 9 , wherein the skin tone determination is weighted less than at least one of the presence determination and the movement determination. 
     
     
         11 . The method of  claim 1  further comprising using combined sensor data to determine presence using a determined distance of a user from the system. 
     
     
         12 . The method of  claim 1  further comprising determining a number of faces in proximity of the system for security, wherein security is provided by powering up partially or powering up into a secure state and requesting credentials for further access. 
     
     
         13 . A method for determining if a user is in proximity of a computing device, the method comprising:
 capturing an image using an image sensor;   computing, using a processor, at least one of the following from the captured image:
 a skin tone detection parameter; 
 a face detection parameter; and 
 a movement detection parameter; 
   utilizing at least one of the skin tone detection parameter, face detection parameter and the movement detection parameter to make a determination as to whether a user is present; and   if it is determined that a user is present, changing a state of the computing device.   
     
     
         14 . The method of  claim 13 , wherein at least the face detection and movement detection parameters are calculated and utilized in making the determination as to whether a user is present. 
     
     
         15 . The method of  claim 13  further comprising:
 calculating each of the skin tone detection, face detection, and movement parameters; and 
 weighting the parameters relative to each other, wherein the skin tone detection parameter is weighted less than the other parameters. 
 
     
     
         16 . The method of  claim 13 , wherein the movement parameter is calculated using a single frame. 
     
     
         17 . The method of  claim 16  further comprising:
 dividing the image into concentric windows; and 
 computing statistics for the concentric windows, wherein changes in at least two windows indicate movement in the image. 
 
     
     
         18 . The method of  claim 16  further comprising:
 dividing the image into non-concentric windows; and 
 computing statistics for the non-concentric windows, wherein changes in at least two windows indicate movement in the image. 
 
     
     
         19 . A computing system comprising:
 a main processor;   a image based presence sensor coupled to the main processor comprising:
 an image sensor; 
 a processor coupled to the image sensor, the processor configured to process the image to determine if a user is present in the image; 
   wherein if the processor determines that a user is present in the image, an indication that a user has been determined to be present is sent from the processor to the main processor and the main processor changes a state of the computing system based on the indication.   
     
     
         20 . The computing system of  claim 19 , wherein the main processor activates a secondary presence sensor based on the indication that a user is present and data from the image based presence sensor and secondary presence sensor are used together to determine at least one of: if a user is present, where the user is located relative to the computer system, or a distance the user is located from the computer system. 
     
     
         21 . The computing system of  claim 19 , wherein:
 if the image based presence sensor determines that a user is present, the image based presence sensor determines at least one of: a number of user's present, a position of the user relative to the computer system, or a distance of the user from the system;   the image based presence sensor provides additional information regarding at least one of: a number of user's present, a position of the user relative to the computer system, or a distance of the user from the system, to the main processor; and   the main processor further changes the state of the computing system based on the additional information.