Abstract:
A system may include a touch surface comprising a plurality of capacitance sensors; and processing circuits operable in a finger touch mode that detects finger touches as user input values, and biometric identification mode that detects a shape value of at least a portion of a user hand, and compares the shape value to stored biometric identification values.

Description:
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/172,346, filed on Apr. 24, 2009, the contents of which are incorporated by reference herein. 
     TECHNICAL FIELD 
     The present disclosure relates generally to biometric identification systems, and more particularly to biometric identification systems having a touch surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of a device according to one embodiment. 
         FIG. 2  is a block diagram of a sense surface that may be included in embodiments. 
         FIG. 3  is a block diagram of a device according to another embodiment. 
         FIG. 4  is a side cross sectional view of a touchscreen device according to a further embodiment. 
         FIG. 5  is a schematic diagram showing one example of processing circuits that may be included in embodiments. 
         FIGS. 6 to 8  show sense value acquisition operations according to various embodiments. 
         FIGS. 9 to 11  show feature extraction operations according to various embodiments. 
         FIG. 12  is a diagram showing angle and position compensation operations that may be included in the embodiments. 
         FIG. 13  is a block schematic diagram of a system according to an embodiment. 
         FIGS. 14 to 17  are diagrams of various particular embodiments. 
         FIGS. 18A to 18E  are a sequence of diagrams showing system operations according to one particular embodiment. 
         FIG. 19  is a flow diagram of a method according to an embodiment. 
         FIG. 20  is a flow diagram of a method according to a further embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments will now be described that show devices, systems and methods for identifying a person based on values derived from two dimensional features of a body portion (e.g., length, width, area of portion(s) of a hand) in contact with a touch surface. Such two dimensional features are in contrast to systems that measure three dimensional body surface features (e.g., fingerprints). In very particular embodiments, a touch surface used for a biometric identification operation may also be used as a user input device. 
     In the particular embodiments shown below, like sections will be referred to by the same reference character but with the first digit(s) corresponding to the figure number. 
     Referring to  FIG. 1 , a device according to one embodiment is shown in a block diagram and designated by the general reference character  100 . A device  100  may include a sense surface  102  and processing circuits  104 . A sense surface  102  may include a number of sense locations (one shown as  106 ), each of which may detect the presence or absence of body part in contact with the touch surface  102 , as well as the extent to which the body part is present (e.g., size or proximity of the body part). In one embodiment, a touch surface  102  has sufficient area to accommodate the body portion being measured. That is, a user does not “swipe” a hand or hand portion over the surface. Rather, the body part may be placed on the surface and maintained substantially motionless for the amount of time needed to acquire a measurement value at a set of sense locations (e.g.,  106 ). 
     A sense surface  102  may derive body shape data in various ways, including but not limited to capacitance sensing or resistance sensing, or any other suitable method for detecting contact of the body part with the surface. 
     Processing circuits  104  may determine if a sensed body part matches stored biometric identification (ID) values to generate a match result (RESULT_ID). In the embodiment shown, processing circuits  104  may include sense circuit  108 , processing section  110 , and biometric data store  112 . Sense circuits  108  may acquire sense values corresponding to sense locations (e.g.,  106 ). In some embodiments sense circuits  108  may include analog-to-digital conversion circuits to convert analog sense values into digital values. In a particular embodiment, sense circuits  108  may be capacitance sense circuits that sense a capacitance value at each sense location (e.g.,  106 ). 
     A processing section  110  may include a position translation section  114 , a feature derivation section  116 , and a feature comparison section  118 . A position translation section  114  may compensate for angular and/or positional offsets between an orientation of a sensed body portion and an orientation corresponding to the biometric data. 
     A feature derivation section  116  may derive two dimensional measurements of a body portion sensed by sense locations (e.g.,  106 ). As noted above, such measurements may correspond to a shape of a body portion. In some particular embodiments, a feature derivation section  116  may generate sensed biometric values corresponding to a shape of a body portion in contact with a sense surface, including but not limited to a width, length, diagonal, contact area, perimeter, and/or perimeter portion, including relative distances between such values. In a very particular embodiment, a sensed body portion may be a hand, and biometric values may measure any of: a finger, a finger portion, multiple fingers, a palm, a portion of a palm, and/or gaps between where portions of a hand contact a sense surface. 
     A comparison section  118  may compare sensed biometric values to stored biometric ID values. Based upon such a comparison, a result value RESULT_ID may be generated indicating whether or not a match has been determined, and to which of the stored ID values a match has occurred. 
     In one embodiment, sections  114 ,  116 ,  118  may be realized by one or more processors executing predetermined instructions with arithmetic logic circuits. However, in alternate embodiments, custom circuits may execute all or a portion of such functions. 
     A biometric data store  112  may store biometric ID data for access by section  118  to compare against sensed biometric values. In one embodiment, a biometric data store  112  may include nonvolatile memory circuits for retaining such values in absence of power to a device. 
     In this way, a device may generate sensed biometric values in response to two dimensional features of body portion placed on a sense surface, and compare such values to stored biometric data values. 
     Referring now to  FIG. 2 , a sense surface that may be included in embodiments is shown in a top plan view and designated by the reference character  202 . A sense surface may utilize capacitance sensing to determine contact of a body portion with the surface, and may be one particular example of that shown as  102  in  FIG. 1 . 
     In the embodiment shown, a sense surface  202  may include sense locations (one shown as  206 ) arranged in an orthogonal array. Each sense location (e.g.,  206 ) may be formed by a discrete sense element (e.g., conductive element at sense location), or a combination of elements (y-direction element and x-direction elements at each location). Capacitance sense elements may be formed from any suitable conductive material, including metals and metal alloys. However, in particular touchscreen embodiments (e.g., those with combination touch detection/display functions), sense elements may be formed from a transparent conductive material, such as indium tin oxide (ITO), as but one example. In the embodiment shown, a capacitance value at a sense location (e.g.,  206 ) may be acquired via array connections  222 - 0  and  222 - 1 . 
     A sense surface  202  may provide direct connections to sense elements to enable direct access to sense locations (e.g.,  206 ). However, a sense surface may optionally include decoding circuits ( 220 - 0  and - 1 ) for selectively accessing sense locations (e.g.,  206 ). 
     In this way, capacitance sensing may be used to acquire two dimensional biometric data based on features of body portion placed on a sense surface. 
     Referring to  FIG. 3 , a device according to another embodiment is shown in a block diagram and designated by the general reference character  300 . In a particular embodiment, device  300  may be one implementation of that shown in  FIG. 1 . 
     A device  300  may include a touchscreen  324  and processing circuits  304 . A touchscreen  324  may include a sense surface  302  formed over a display  326 . A sense surface  302  may take the form of those described herein, or equivalents, but include transparent sensor elements to ensure that display  326  may be observed through the touch surface  302 . A display  326  may be any type of display for the device application, and may include, without limitation, a liquid crystal display (LCD), light emitting diode (LED) display (including organic LED (OLED) displays), or electrophoretic (or other so-called electronic ink type) displays. 
     A touchscreen  324  may provide a biometric input, a user input, and a user output. A biometric input may convey sense values corresponding to a body portion shape according to techniques described herein, and equivalents. A user input may convey touch locations and/or touch types generated by a user touching touch surface  302 . In particular embodiments, sense values for both types of inputs (e.g., biometric ID and touch detection) may be generated in the same fashion (i.e., scanning sense locations). A user output of touchscreen  324  may be provided by display  326  presenting visual images. In particular embodiments, touch inputs in combination with a display may create a user interface for the device. 
     In the embodiment of  FIG. 3 , processing circuits  304  may perform multiple functions, including a biometric ID function and a user input function. In a biometric ID function, processing circuits  304  may determine if values generated from a sensed body part match stored biometric ID values. In a user input function, processing circuits  304  may derive locations of one or more touches, so that such touches may be interpreted as user inputs. A user input function may distinguish types of touches as well. For example, touch speeds and/or directions may be evaluated to detect particular types of touch events (e.g., taps, motions). 
     In the particular embodiment shown, processing circuits  304  may include sense circuit  308 , a processor section  328 , first memory  330 , and a second memory  332 . 
     Sense circuits  308  may operate as described for item  108  in  FIG. 1 , or in an equivalent manner. 
     A processor section  328  may include one or more processors that execute predetermined instructions located within a first memory  330 . A processor section  310  may generate output signals RESULT, which may vary according to mode. More particularly, in an ID mode, output signals RESULT may indicate whether or not a sensed body portion is considered to match stored biometric ID data. In contrast, in a touch mode, output signals RESULT may identify location and/or type of touch on a sense surface  302 . 
     A first memory  330  may be a substantially nonvolatile memory that stores instructions for execution by a processor section  310 , as well as data for use by processor section  310 . In the particular embodiment shown, first memory  330  may be divided into ID instructions  340 , touch instructions  342 , and data storage  344 . 
     ID instructions  340  may include a translation routine  334 , a feature routine  336 , and a compare routine  338 . A translation routine  334 , feature routine  336  and compare routine  338  may execute the same or equivalent operations described for position translation section  114 , feature derivation section  116 , and feature comparison section  118 , respectively, of  FIG. 1 . Still further, translation and feature routines  334 / 336  may be portions of one analysis routine. In a very particular embodiment, such routines may be firmware for one or more integrated circuit devices. 
     Sense instructions  342  may include a touch routine  346  that derives position data for touches and/or interprets types of touches. In one embodiment this may include determining the presence of multiple touch locations (e.g., multi-touch input). 
     Data storage  344  may store biometric data  348  for use by processing section  328  when executing a compare routine  338 , to determine if a sensed body portion is determined to match biometric data  348 . It is understood that a “match” is not an exact match, and may include tolerance limits. 
     A second memory  332  may store values sensed from touchscreen  324  for manipulation by processor section  328 . In a particular embodiment, a second memory  332  may be substantially volatile, losing data in the absence of power. 
     In one very particular embodiment, processing circuits  304  may be formed all, or in part by a programmable embedded system-on-chip from the PSoC® family of integrated circuit devices, manufactured by Cypress Semiconductor Corporation, of San Jose, Calif., U.S.A. 
     While the embodiment of  FIG. 3  shows routines stored in a nonvolatile memory, alternate embodiments, may include loaded such routines into an operational memory from some other location of a larger system incorporating device  300 . 
     In this way, a device may include a touchscreen which operates a biometric data input in one mode, and user control input in another mode. 
     Referring to  FIG. 4 , a device according an embodiment is shown in a side cross sectional view, and designated by the general reference character  400 . A device  400  may be one very particular implementation of that shown in  FIG. 3 . 
     A device  400  may be conceptualized as including a touchscreen  424  and a circuit portion  450 . A touchscreen  424  may include a display  426  and a sensor array  452 . A sensor array  452  may be formed over display  426  and separated therefrom by a first transparent layer  454 - 0 . A second transparent layer  454 - 1  may be formed over sensor array  452  to form a sense surface  402 . 
     A circuit portion  450  may be formed opposite to an image presenting side of display  426 . A circuit portion  450  may include processing circuits  404  that may perform biometric ID functions, as well as user input functions, as described herein and equivalents. A circuit portion  450  may include additional circuits  456  for controlling a display function of display  426  and run other applications for the device  400 . 
     In this way, processing circuits that perform biometric ID functions may be integrated into a touchscreen device. 
     Referring now to  FIG. 5 , one example of processing circuits  504  that may be included in embodiments is shown in a schematic diagram. Processing circuits  504  may be formed in a same IC, and may include an analog portion  504 - 0  and a digital portion  504 - 1 . An analog portion  504 - 0  may connect to a number of sense elements  560 - 0  to -n at input/outputs (I/Os)  562 - 0  to -n. I/Os ( 562 - 0  to -n) may be connected to a same sample node  558  by corresponding switches  564 - 0  to -n. Such an arrangement may enable sense elements ( 560 - 0  to -n) to be sequentially connected to sample node  558  for a capacitance measurement. Sequential sampling may provide for lower power consumption and fewer processing circuits than approaches that process signals in parallel. 
     An analog portion  504 - 0  may also include a comparator  566 , a discharge switch  568 , a charge switch  570 , and a control and count circuit  572 . In combination, these circuit elements may generate a count value representative of a sense element value (e.g., capacitance) sensed at sample node  558 . Such a sensing operation may be according to integration techniques, successive approximation techniques, sigma-delta conversion, or any other suitable technique for measuring a signal at sample node  558 . Thus, an analog portion  504 - 0  may include analog-to-digital conversion circuits that generate a digital value (counts) from an analog value (raw value detected at sample node  558 ). 
     Referring still to  FIG. 5 , a digital portion  504 - 1  may include a microcontroller  574 . A microcontroller  574  may execute predetermined operations on received count values to perform a biometric compare operation and/or determine the position of such objects. 
     Having described various devices that may generate two dimensional data on body portions, particular data acquisition and processing operations will now be described. 
     Referring to  FIG. 6 , acquisition of sense values according to one particular embodiment is shown in a top plan view.  FIG. 6  shows a sense surface  602  divided into sense locations identifiable by X and Y locations (shown by X and Y axes).  FIG. 6  also shows a body part position  676  (in this example a hand shown by a dashed line) above a sense surface  602 , as well as body part touch locations (solid lines, one shown as  678 ) showing where a body part portion contacts the sense surface  602 . In the embodiment shown, it is assumed that one is instructed to keep their fingers together when sense data is being acquired. 
       FIG. 6  shows count values that may be acquired according to one very particular embodiment. For example, sense location (3,1) (x, y coordinates) has a count value of “133”, while sense location (4,2) has a count value of “255”. In the very particular embodiment shown, a count value may correspond to the amount by which a sense location is physically contacted by a body part. 
     Referring to  FIG. 7 , a sense operation like that of  FIG. 6  is shown in a top plan view, but with a sense surface  702  of finer resolution that acquires sense values for two fingers. As in the case of  FIG. 6 ,  FIG. 7  shows a sense surface  702  divided into sense locations identifiable by X and Y locations, with body part position  776  above a sense surface  702 , as well as body part touch locations (one shown as  778 ). Corresponding count values are shown in sense locations (e.g., sense location (3,6) has a count value of “255”). 
     Referring now to  FIG. 8 , another sense operation like that of  FIG. 8  is shown, but with a sense surface  802  acquiring sense values for a palm.  FIG. 8  only shows body part touch locations (one shown as  878 ). Corresponding count values are shown in the same manner as  FIGS. 6 and 7  (e.g., sense location (4,2) has a count value of “255”). 
     In this way, embodiments may generate count values based on the amount by which body portion(s) contact sense locations on a sense surface. Such count value may be used to generate biometric data. 
     Once sense values for a body portion are acquired, two dimensional features may be generated from such values. Very particular examples of how such features may be generated will now be described. It is noted that the examples are understood to illustrative and any suitable biometric value generation method may be utilized and/or varied according to the body portion to be sensed, the type of sensor used, type of biometric data measured, and resources of the sensing system. 
     Referring to  FIG. 9 , measurement values according to one particular embodiment are shown in a top plan view.  FIG. 9  shows values that may be generated in response to sense values shown in  FIG. 6 . Such measurement values may include any of: finger length measurements (one shown as  980 - 0 ), finger width measurements (one shown as  980 - 1 , and in this embodiment a width of multiple fingers), palm length measurements (one shown as  980 - 2 ), or palm width measurements (one shown as  980 - 3 ). 
     Measurements may be made according to various methods. As but one example, a total body portion region may be detected by peripheral sense locations having values over a predetermined threshold. Minimum (and/or maximum) values, or differences in such values, may designate start and ending of a measurement region. A measurement value for a measurement region may then vary according to the values at sense locations within the measured region and/or adjacent to such a region. 
     Referring to  FIG. 10 , measurement values according to another particular embodiment are shown in a top plan view.  FIG. 10  shows values that may be generated in response to sense values shown in  FIG. 6 . Such measurement values may include shapes of a palm (one shown as  1082 ). 
     Measurements may be made according to various methods. In one very particular embodiment, a palm region may be derived from a total body region by detecting minimum corresponding to gaps between finger and palm regions. Contiguous sense locations above a threshold may be considered to belong to a same palm portion. Such areas may be increased or decreased based on values of bordering sense locations. 
     Referring to  FIG. 11 , measurement values according to a further particular embodiment are shown in a top plan view.  FIG. 11  also shows values that may be generated in response to sense values shown in  FIG. 6 . Such measurement values may include shapes of touch gaps (one shown as  1184 ) arising between areas where a body portion contacts a sense surface 
     Measurements may be made according to various methods. In one particular embodiment, gaps locations derived from minimum values within a contact region. Contiguous sense values below a threshold may be considered to belong to a same gap. Gap areas may be increased or decreased based on values of bordering sense locations. 
     As noted above, and repeated here, the described measurement approach is but one example of possible measurement approaches. 
     To ensure consistent measurement of biometric values, a device may compensate for difference in orientation between the position of a sensed body portion, and the position of a body portion used to derive a biometric reference value. One particular compensation approach that may be included in the embodiments is shown in  FIG. 12   
     Referring to  FIG. 12 , measurement values are shown in a top plan view for hand like that of  FIG. 6 . However, the hand is rotated and offset with respect to an orientation like that of  FIG. 6 . 
     Compensation for such rotation and offset may be made according to various methods. In one particular embodiment, features of the scanned body part may be identified to derive the orientation of the body part. In the particular embodiment of  FIG. 12 , feature points may be identified (e.g., largest positive Y location  1286 - 0 , a minimum value surrounded by large values  1286 - 1 ) to derive an angular offset  1288 . In addition, one feature point location (e.g.,  1286 - 1 ) may be compared to a reference point  1290  to determine a position offset. 
     Such offset values may then be utilized to generate sense values and biometric features. 
     In alternate embodiments, measurement of biometric features may be derived with reference to feature points (e.g.,  1286 - 0 / 1 ). That is, compensation and calculation are part of a same operation. 
     Alternate embodiments may use any suitable compensation steps, according to various factors, including but not limited to: available processing powers, desired speed of result, amount of offset expected. 
     A device that acquires biometric data and may also serve as a user touch input device may be included in various types of systems to provide both security and touch input information to a host device. Particular system embodiments will now be described. It is stressed that such embodiments are intended to be illustrative, and not exhaustive. 
     Referring to  FIG. 13  a system according to an embodiment is shown in a block schematic diagram and designated by the general reference character  1392 . A system  1392  may be a computing device including, but not limited to, desktop computing devices as well as portable computing devices, such as handheld electronic devices. A system  1392  may include a detection device  1300  and a computing section  1394 . 
     A detection device  1300  may correspond to any of the devices described herein, or equivalents, and may operate in an ID mode to make a biometric reading of a body portion, and in a touch mode to provide user input values to the system. 
     A computing section  1394  may be conceptualized as having a number of operational layers, including a security section  1395 , user interface  1396  and a main program layer  1398 . Security section  1395  may prevent access to some or all of the functions of system  1392  according to biometric match results from device  1300 . 
     User interface software  1396  may accept touch position and/or type data from device. In some embodiments, user interface software  1396  may generate interrupts to notify when input events occur based on the detection and/or movement of a detected option. Alternatively, position information may be periodically polled. 
     A main programming layer  1398  may include an operation system (OS) as one or more application programs (APP) for executing functions in response to inputs from detection device  1300 . A computing section  1394  may physically be implemented by one or more processors that execute predetermined instructions stored in a memory. 
     It is noted that in an embodiment like that of  FIG. 13 , a computing section  1394  may receive input values from other devices and/or interfaces in conjunction with those from detection device  1300 . 
     Referring to  FIG. 14 , a very particular system embodiment is shown in a front plan view and designated by the reference character  1492 . A system  1492  may be a display device, and may be one implementation of that shown in  FIG. 13 . 
     A system host  1494  may include a display device for presenting an image, including viewing images and/or a graphical user interface. Such a system  1492  may include, without limitations, stand alone computer displays, computers with integrated displays, televisions, or electronic picture frames, to name just a few. 
     In the particular embodiment shown, a display surface may be a touchscreen  1424 . Such a touchscreen  1424  may serve to acquire biometric data in one mode, and user control touch inputs in another mode. Sense surface  1402  may take the form of any of those shown herein, and equivalents. Sense surface  1402  may be connected to processing circuits (not shown), to execute biometric and touch position operations according to the embodiments herein, and equivalents. 
     Referring to  FIG. 15 , another particular embodiment is shown in a perspective view and designated by the reference character  1592 . A system  1592  may be a one implementation of that shown in  FIG. 13 . 
     A system  1592  may be a portable electronic device, and may include without limitations, a cellular phone, personal digital assistant, personal media player, personal gaming device, or tablet computer, to name but a few. As in the case of  FIG. 15 , system  1592  may include a touchscreen  1524  having biometric ID and touch input capabilities. A sense surface of touchscreen  1524  may take the form of any of those shown herein, and equivalents. 
     Referring to  FIG. 16 , a further embodiment is shown in a top plan view and designated by the reference character  1692 . A system  1692  may be an implementation of that shown in  FIG. 13 . 
     A system  1692  may include a portable “laptop” type computer. System  1692  may include have a touch pad that serves as a touch surface  1602  for a device having biometric and touch input capabilities, as described herein, and equivalents. 
     Referring to  FIG. 17 , another embodiment is shown in a front plan view and designated by the reference character  1792 . A system  1792  may be a one implementation of that shown in  FIG. 13 . 
     A system  1792  may include a network phone, such as an Internet telephony device (e.g., voice-over-Internet-protocol (VoIP) phone). System  1792  may include a touchscreen  1724  biometric and touch input capabilities, as described herein, and equivalents. 
     Having described various systems, operations of a system will now be described with reference to  FIGS. 18A to 18E .  FIGS. 18A to 18E  show a system  1892  having a touchscreen  1824  according to embodiments described herein, and equivalents. 
     Referring to  FIG. 18A , in response to a predetermined event (e.g., start-up, user logout, etc.) a touchscreen  1824  may display an initial message  1896  that a device may not be accessed without a security procedure. 
     Referring to  FIG. 18B , to initiate a security procedure, a touchscreen  1892  may display a request  1898  for the placement of a body portion on a touchscreen  1824 . 
     Referring to  FIG. 18C , a user may place a body portion (in this case a hand) on a sense surface of touchscreen  1824 . In response to contact with a body portion, a system  1824  may begin acquiring sense data and make biometric measurements as described herein, and equivalents. 
     Referring to  FIG. 18D , if a body portion matches a stored biometric profile, a system  1892  may enable access by a user presenting an interface screen  1897  (i.e., the system  1892  may be unlocked). In addition, a touchscreen  1824  may switch to a user input mode, to enable interaction with elements (e.g., icons) of an interface screen  1897 . If a body portion does not match a stored profile, a system  1892  may continue to request placement of a body portion on the screen. 
     Referring to  FIG. 18E , with system  1892  unlocked, a user may interact with the system with touches on touchscreen  1824 . 
     In this way, a system may request a user to contact a sense surface with a body portion for a biometric measurement to enable access to the system, including user control inputs through the sense surface. 
     While embodiments may include sense devices and systems, other embodiments may include methods of making biometric measurements as described in above embodiments. Additional method embodiments will now be described below. 
     Referring to  FIG. 19 , a method according to a first embodiment is shown in a flow diagram and designated by the general reference character  1983 . A method  1983  may include acquiring capacitance values for a sense surface (box  1995 ). A two dimensional representation of a body portion may then be made (box  1993 ). Biometric features may then be extracted from such a two dimensional representation (box  1991 ). 
     Referring still to  FIG. 19 , extracted biometric features may then be checked to see if they match biometric data (box  1989 ). If no match is found (N from  1989 ), a no match indication may be generated (box  1987 ). In contrast, if a match is found (Y from  1989 ), a match indication may be generated (box  1985 ). 
     Referring to  FIG. 20 , a method according to another embodiment is shown in a flow diagram and designated by the general reference character  2051 . 
     A method  2051  may include locking a system (box  2049 ). Such an action may prevent all or a portion of system features to be inaccessible by a user. A user input on a sense surface may be requested (box  2081 ). Such an action may include prompting a user to place a body portion on a sense surface. In very particular touchscreen embodiments, such an action may include displaying images to assist in properly aligning the body portion on the touchscreen. Sense data may then be acquired (box  2079 ). 
     A method  2051  may check to determine if a user feature is present (box  2077 ). Such an action may help avoid executing biometric analyses while a user is only providing finger touch inputs and/or a user has less than all of a requested body portion on a sense surface. In particular embodiments, such an action may make an initial determination that touches have been sensed on a minimum number of sense locations, or minimum number of consecutive sense locations. 
     If a user feature is not present (N from box  2077 ), a method  2051  may again request user input (return to box  2081 ). If a user feature is determined to be present (Y from box  2077 ), a method  2051  may check for too much movement by a user (box  2075 ). Such an action may compare sequential sets of sense values acquired from a scan surface to determine if a body portion has moved. If movement is detected, and it is greater than some predetermined amount and/or rate (Y from  2075 ), a user may be instructed to cease movement (box  2073 ) and sensing operations may repeat (return to box  2081 ). 
     However, if movement is not detected (N from  2075 ), acquired sense values may be considered sufficient to perform a biometric analysis. 
     Referring still to  FIG. 20 , a method  2051  may compensate for the orientation of a body portion (box  2071 ). In particular embodiments, such an action may include compensating for angular rotation and offset from a preset measuring point, as described herein and equivalent operations. A two dimensional representation of a body portion may then be made (box  2069 ). Biometric features may then be extracted from such a two dimensional representation (box  2067 ). Extracted biometric features may then be compared to biometric ID data (box  2065 ). If extracted biometric features are outside of limits (OUTSIDE LIMITS from  2065 ), a no match indication may be generated (box  2063 ) and a system may remain locked. In the particular embodiment shown, a method  2051  may return to requesting user input (box  2081 ). 
     If extracted biometric features are within limits (w/in LIMITS from  2065 ), a system may be unlocked (box  2061 ), allowing a user to access previously locked functions. Further, different features may be unlocked depending upon the ID match that has occurred. Such a function may allow different users to log into personal accounts on a device based on an ID match. 
     In the particular embodiment of  FIG. 20 , once unlocked, a method  2051  may switch to a touch sensing mode. Once again, sense data may be acquired (box  2059 ). However, rather than execute biometric analysis (or check for suitability for biometric analysis), a method  2051  may derive touch points from sense data (box  2057 ). Such an action may include generating position values for finger touches (and/or types of touches). Touch point data may be made available as a user input (box  2055 ). A method  2051  may remain in the touch sensing mode (Y from  2053 ), or may move onto other actions (N from  2053 ). 
     It should be appreciated that in the foregoing description of exemplary embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure aiding in the understanding of one or more of the various aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention. 
     It is also understood that the embodiments of the invention may be practiced in the absence of an element and/or step not specifically disclosed. That is, an inventive feature of the invention may be elimination of an element. 
     Accordingly, while the various aspects of the particular embodiments set forth herein have been described in detail, the present invention could be subject to various changes, substitutions, and alterations without departing from the spirit and scope of the invention.