PATENT DOCUMENT

Publication Number: US-10068120-B2
Application Number: US-201313843119-A
Country: US
Kind Code: B2

Title: High dynamic range fingerprint sensing

Abstract:
Improving fingerprint image measurement despite damage to the stratum corneum. Determining whether a fingerprint image is adequate for matching with a database. If not, re-measure those image portions that are inadequate (overexposed or underexposed), such re-measuring a minimal selection of image portions. An amount of time or power to re-measure is minimized. Improving fingerprint image data collection despite fixed pattern noise like saturated bars in blocks of picture elements. Determining a histogram of grayscale values, removing fixed pattern noise, and expanding real histogram values to obtain more bits of precision.

Claims:
We claim: 
     
       1. A method for receiving fingerprint information, comprising:
 receiving, at a first time, a first fingerprint element image at first signal conditioning settings, the first fingerprint element image captured by an array of sensor elements in a first image capture operation; 
 measuring an exposure of the first fingerprint element image to determine whether a first portion of a first plurality of portions of the first fingerprint element image is underexposed or overexposed; and 
 in response to determining that the first portion of the first fingerprint element image is underexposed or overexposed:
 receiving, at a second time different from the first time, a second fingerprint element image at second signal conditioning settings, the second fingerprint element image captured by the array of sensor elements in a second image capture operation; and 
 combining a second portion of a second plurality of portions of the second fingerprint element image with a subset of the first plurality of portions of the first fingerprint element image to generate a composite; wherein 
 
 the second portion of the second fingerprint element image corresponds to the first portion of the first fingerprint element image that is underexposed or overexposed. 
 
     
     
       2. The method of  claim 1 , wherein the first signal conditioning settings are different from the second signal conditioning settings. 
     
     
       3. The method of  claim 2 , wherein:
 the first signal conditioning settings comprise a first gain setting; and 
 the second signal conditioning settings comprise a second, unique gain setting. 
 
     
     
       4. The method of  claim 1 , wherein each of the first fingerprint element image and the second fingerprint element image is captured by a unique set of the array of sensor elements. 
     
     
       5. The method of  claim 1 , wherein each of the first fingerprint element image and the second fingerprint element image is captured by a same set of the array of sensor elements. 
     
     
       6. The method of  claim 1 , wherein measuring the exposure of the first fingerprint element image to determine whether the first portion of the first fingerprint element image is underexposed or overexposed comprises:
 measuring the exposure of the first portion to determine that the first portion is over-saturated. 
 
     
     
       7. The method of  claim 1 , wherein measuring the exposure of the first fingerprint element image to determine whether the first portion of the first fingerprint element image is underexposed or overexposed comprises:
 measuring the exposure of the first portion to determine that the first portion is under-saturated. 
 
     
     
       8. The method of  claim 1 , further comprising:
 in response to determining that the first portion of the first fingerprint element image is underexposed or overexposed, instructing the array of sensor elements to re-image a finger, thereby generating the second fingerprint element image. 
 
     
     
       9. The method of  claim 8 , wherein the second fingerprint element image is generated at a distinct gain setting. 
     
     
       10. The method of  claim 1 , further comprising:
 in response to determining that the first portion of the first fingerprint element image is underexposed or overexposed, instructing the array of sensor elements to re-image only a portion of a finger corresponding to the first portion of the first fingerprint element image that is inadequately exposed, thereby generating the second portion of the second fingerprint element image. 
 
     
     
       11. The method of  claim 1 , further comprising:
 determining whether the second fingerprint element image, captured at second signal conditioning settings, will adequately expose the second portion of the second fingerprint element image corresponding to the first portion of the first fingerprint element image that is underexposed or overexposed; and 
 in response to such a determination, instructing the array of sensor elements to re-image a finger, thereby generating the second fingerprint element image. 
 
     
     
       12. A fingerprint imaging apparatus, comprising:
 a fingerprint sensor comprising an array of sensor elements; 
 at least a first amplifier operatively connected to the fingerprint sensor; and 
 a processing unit operatively connected to the fingerprint sensor and the at least one amplifier, and configured to:
 at a first time, cause a first image to be captured by the array of sensor elements of the fingerprint sensor in a first single image capture operation; 
 determine if a first portion of a first plurality of portions of the first image is underexposed or overexposed; and 
 in response to determining that the first portion of the first fingerprint element image is underexposed or overexposed:
 at a second time, cause a second image to be captured by the array of sensor elements of the fingerprint sensor in a second single image capture operation; and 
 
 combine a second portion of a second plurality of portions of the second image with a subset of the plurality of portions of the first image to generate a composite image; wherein 
 
 the second portion of the second image corresponds to the first portion of the first image that is underexposed or overexposed. 
 
     
     
       13. The fingerprint imaging apparatus of  claim 12 , further comprising:
 a memory operatively connected to the processing unit and storing a plurality of fingerprint images; 
 wherein the processing unit is operative to compare the composite image to at least one of the plurality of fingerprint images. 
 
     
     
       14. The fingerprint imaging apparatus of  claim 13 , further comprising a multiplexer operatively connected to the fingerprint sensor; wherein:
 each of the plurality of sensor elements outputs a signal, thereby forming a plurality of signals; and 
 the multiplexer is operative to multiplex the plurality of signals. 
 
     
     
       15. The fingerprint imaging apparatus of  claim 14 , further comprising at least a second amplifier operatively connected to the fingerprint sensor and the processing unit. 
     
     
       16. The fingerprint imaging apparatus of  claim 15 , wherein:
 the at least the first amplifier is operative to amplify a first subset of the plurality of signals; 
 the at least the second amplifier is operative to amplify a second subset of the plurality of signals; and 
 the first and second subsets of the plurality of signals are different. 
 
     
     
       17. The fingerprint imaging apparatus of  claim 12 , wherein the processing unit is embedded in a common substrate with the fingerprint sensor. 
     
     
       18. A method of receiving fingerprint information, comprising:
 capturing, at a first time, a first fingerprint element image in a first image capture operation, the first fingerprint element image comprising a plurality of portions; 
 receiving a first portion of the plurality of portions; 
 amplifying the first portion at a first signal conditioning setting, thereby producing a first conditioned portion; 
 determining whether the first conditioned portion is underexposed or overexposed; 
 in response to determining that the first conditioned portion is underexposed or overexposed, capturing, at a second time, a second portion of a second fingerprint image, corresponding to the first portion, in a second image capture operation; 
 amplifying the at least the second portion at a second signal conditioning setting, thereby producing a second conditioned portion; and 
 employing the second conditioned portion with a subset of the plurality of portions of the first fingerprint element image to form a composite fingerprint image. 
 
     
     
       19. The method of  claim 18 , wherein the first and second portions generally correspond to a single area of a fingerprint. 
     
     
       20. The method of  claim 19 , further comprising:
 determining the existence of a fixed pattern noise element in the first portion; and 
 removing the fixed pattern noise element from the first portion. 
 
     
     
       21. The method of  claim 19 , further comprising determining a peak portion of a histogram of grayscale values in the first portion; and removing the peak portion.

Description:
TECHNICAL FIELD 
     This application generally relates to high dynamic range sensing, and more particularly to dynamically adjusting a sensing range of a biometric sensor. 
     BACKGROUND 
     It sometimes occurs that, in devices that attempt to match fingerprints or similar data structures, collecting fingerprint or similar information can be subject to errors or noise. One form of errors can occur when the user&#39;s finger has abrasions, gaps, pits, scratches, or other damage to its outer layer. These artifacts can affect a fingerprint sensor negatively, particularly in that they can cause the capacitance measured by the sensor to be measured abnormally. For example, the in the region of such artifacts, the fingerprint sensor might measure an abnormally high capacitance or an abnormally low capacitance, either way causing a fingerprint image derived from the sensor to be difficult to match against a database of known fingerprints. 
     One possible response to measurement, by the sensor, of an abnormally high capacitance or an abnormally low capacitance, is to re-measure the capacitance of the user&#39;s finger, such as with other parameters for measuring capacitance. While this technique might generally have the benefit of obtaining a fingerprint image that is less subject to problems due to these artifacts, it is subject to the drawback of taking substantial time to re-measure the capacitance of the user&#39;s finger. During this substantial time the user might grow impatient, move his finger, or otherwise degrade the operation of the fingerprint sensor. 
     It also sometimes occurs that, in devices that attempt to sense image data, such as fingerprints and similar image data, collecting image data can be subject to a substantial level of fixed pattern noise. Collected image data can include artifacts, whether of the nature of the image or of the nature of the method of collection of image data. For example, fingerprint image data can include vertical bars in the image. In such cases, it might occur that blocks or tiles of multiple elements of image data can include one (or more) lines that have a maximum grayscale level, as if a black line had been drawn on the image data. Blocks may be 8×8, 10×10, or any other suitable size, and need not be square. 
     In such cases, it might also occur that adjacent elements of image data can include one (or more) lines that have a maximum greyscale level, as though a black shape of arbitrary area had been drawn on the image data. In other cases, it might also occur that one (or more) lines can be present in a block of image data, but not so many lines that the block of image data cannot be used. In such cases, it might also occur that the fixed pattern noise is more significant than the raw data, such as wherein the image data might be read by a sensor at values near 200 microvolts, while the fixed pattern noise might be read by the same sensor at values near 10 millivolts. This fixed pattern noise can pose a particular problem in that large noise values can reduce the device&#39;s sensitivity to midrange grayscale levels, in an effort to distinguish differing noise levels. 
     Each of these examples, as well as other possible considerations, can cause one or more difficulties as a result of excessive cost (such as time or processing power required) to image or match fingerprints. 
     SUMMARY OF THE DISCLOSURE 
     This application provides techniques, including devices and structures, and including method steps, that can improve fingerprint image measurement, with respect to time and power requirements, notwithstanding the presence of artifacts as described above. 
     In one embodiment, a processing unit can determine a fingerprint image in response to a measurement of the user&#39;s finger and resulting imaging of a user&#39;s fingerprint, and can determine whether that fingerprint image is adequate for matching with a fingerprint image database (such as a database of known fingerprints of known users). If the processing unit determines that the fingerprint image will not be adequate for matching, the processing unit can re-measure those portions of the image that the processing unit determines are inadequate. 
     For example, if the user&#39;s finger is subject to artifacts as described above, the processing unit can determine that some portions of the fingerprint image are overexposed or underexposed. This can have the effect that those portions of the fingerprint image might not show adequate detail with respect to fingerprint ridges, ridgelines, pores, or other indicia that could be used for matching with a fingerprint image database. 
     In one embodiment, the processing unit can identify those portions of the fingerprint image that are overexposed or underexposed, and re-measure a minimal selection of portions of the fingerprint image. This can have the effect that the amount of effort (such as time required to re-measure, or power required to re-process) to re-measure those portions of the fingerprint image can be minimized. This can have the effect of reducing the wait time involved for the user to have their fingerprint measured and matched. 
     Although this application describes exemplary embodiments and variations thereof, still other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the disclosure. As will be realized, the disclosure is capable of modifications in various obvious aspects, all without departing from the spirit and scope of the present disclosure. The drawings and detailed description are intended to be illustrative in nature and not restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a schematic drawing of application of a user&#39;s finger to a fingerprint sensor. 
         FIG. 2  shows a conceptual drawing of fingerprint image. 
         FIG. 3  shows a conceptual drawing of a first method of operation. 
         FIG. 4A  generally shows a histogram for a fingerprint image. 
         FIG. 4B  shows a conceptual drawing of a second method of operation. 
         FIG. 5A  shows a conceptual drawing of communication channel between a device and a computing system. 
         FIG. 5B  shows a schematic drawing of a touch I/O device including a fingerprint recognition system. 
     
    
    
     DETAILED DESCRIPTION 
     Overview 
     Generally, embodiments disclosed herein may take the form of an apparatus or method for amplifying a dynamic range of a sensor, such as a fingerprint sensor. Other embodiments may amplify the sensing range of any fingerprint sensor. In certain embodiments, the effective resolution of the sensor may be expanded. Likewise, false data due to scratches, cuts, surface imperfections and the like on a finger may be accounted for by dynamically adjusting the gain and/or range of sensitivity of the sensor. 
     It should also be appreciated that certain portions of fingerprint data may be amplified and expanded to provide additional effective resolution to the values (whether capacitive or otherwise) captured by the fingerprint sensor. Embodiments described herein may provide techniques and systems for amplifying a signal, corresponding to one or more features of a fingerprint, in comparison to a carrier wave for that signal and/or resulting fixed pattern noise. With respect to fingerprint sensors, fixed pattern noise may result from certain hardware limitations and/or characteristics of a finger being imaged. Fixed pattern noise often causes one or more portions of an imaged fingerprint (or portion of a fingerprint) to appear solid black or solid white. This may occur due to differences in the responsivity of certain portions of a sensor array. For example, one channel or imaging element may experience a higher gain than others, due to a variety of factors that may include variations in signal amplification, variations in imaging element size, differences in imaging sensor material between imaging elements, electrical interference from other circuitry, and the like. The exact cause of fixed pattern noise may be indeterminate or even relatively irrelevant; the effect on the captured image may nonetheless be real. By dynamically adjusting the range of operation of the sensor, defects due to fixed pattern noise may be overcome. 
     Accordingly, embodiments described herein may compensate for, ignore, or otherwise discard fingerprint imaging errors due to fixed pattern noise. 
     Fingerprint Capture 
       FIG. 1  shows a conceptual drawing of application of a user&#39;s finger to a fingerprint sensor. 
     A fingerprint sensor system can include a fingerprint sensor, such as a fingerprint sensor, to which the user can apply their finger, or a portion thereof. The fingerprint sensor may image one or more features of the finger, such as ridges and valley of a fingerprint. Generally, such captured fingerprint images may be captured a portion of block at a time. For example, a fingerprint sensor may capture a certain number of blocks, each made up of individual “picture elements,” with every scan. In one embodiment an a certain number of picture elements (for example, an 8×8 array) may correspond to, or form, a single block or tile (the terms “block” and “tile” are used interchangeably herein). Each picture element may correspond to the smallest size information element that may be captured by a fingerprint scanner. The picture elements may be assembled into blocks, which in turn may be assembled into a captured fingerprint image. It should be appreciated that a “fingerprint image” need not refer to an image that includes the entirety of a fingerprint. Rather, only a portion of a fingerprint may be present in any given fingerprint image. In some embodiments, a single fingerprint image may be sufficient to match against stored fingerprint data and identify a user, while in other embodiments multiple images or portions of images may be required. Further, it should be appreciated that a “fingerprint image” or “captured fingerprint image” may be represented by, or analogous to, a data set abstracted from such an image, one example of which is a ridgeflow map. Thus, discussions of one are intended to encompass the other. 
     Any suitable fingerprint sensor may be used with embodiments and techniques disclosed herein. Suitable fingerprint sensors include capacitive sensors, ultrasonic sensor, optical sensors, pyro-electric sensors, and so on. 
     The fingerprint sensor system can be coupled to a processing unit (as described herein, below), which can maintain a fingerprint information database, and which can attempt to match the captured image against information about known fingerprints from known users. 
     For example, when the processing unit or other element of the embodiment matches the captured fingerprint image against a known fingerprint from an authorized user, the processing unit can take one or more actions in response thereto. For example, the processing unit can authorize usage of a device for an individual procedure, for a sequence of procedures, for a selected time duration, until a trigger indicating that the user is no longer authorized, or until the user de-authorizes the device. For example, the user can de-authorize the device by turning the device off, or by handing the device to another user. 
     In one embodiment, the fingerprint sensor system can be coupled to and be used to authorize a device. For example, the device can be a smart phone, tablet computing device, portable computer, touch screen on an appliance or automobile or similar device, or any other device having touch device capability, a function button, or other elements related to the nature of the technology described herein. As discussed in greater detail with respect to  FIG. 5 , the device can include a processing unit, program and/or data memory, instructions or modules directing the processing unit to perform functions as described herein, and other components. The device can also include data memory storing a fingerprint database that includes images and/or other data relating to fingerprints or other biometric information suitable for identifying and authenticating one or more users of the device. For example, the data memory can include one or more images of fingerprints, one or more transformations of fingerprints, other data sets abstracted from fingerprints, or other information with respect to fingerprints. 
     In one embodiment, the fingerprint sensor system includes a dielectric element  112 , to which the user applies his finger, or a portion thereof, so that an associated sensor may generate a captured fingerprint image. For example, the dielectric element  112  can include or be part of a cover glass element of the device, such as the display image cover of a tablet computing device, a smart phone, or similar device. The cover glass element can include a dielectric such as sapphire, glass, chemically treated glass, plastic, resin, or some other material suited to the purposes or functions described herein. 
     In one embodiment, the user places his finger  114  in contact (or near-contact) with the dielectric element  112 . The user&#39;s finger  114  includes at least a layer of live skin  116  and a layer of dead skin  118 , the latter sometimes referred to as the “stratum corneum.” The layer of dead skin  118  is placed in contact with the dielectric element  112 . 
     It might occur that the stratum corneum, the layer of dead skin  118 , includes one or more abrasions, gaps, pits, scratches, or other damage  120  to its outer layer, such as described above. As mentioned, this damage  120  can have an effect on the fingerprint image measured by the fingerprint sensor system. When coupled with fixed pattern noise, for example, the gap between the sensor and the skin caused by the damage  120  may cause that portion of a captured fingerprint image to be either overexposed (e.g., appear black in the corresponding image) or underexposed (e.g., appear white in the corresponding image). Either way, that data is not only inaccurate but may prevent an embodiment from successfully matching a captured fingerprint to a stored fingerprint, and thereby identifying a user. 
     In one embodiment, the fingerprint image  212  (shown conceptually in  FIG. 2 ) can include a set of fingerprint image elements  216  (shown with respect to  FIG. 2 ). For example, one or more sensing elements can measure the fingerprint image elements  216 . The fingerprint sensor may be formed from or include a number of sensing elements, which may be arranged in a variety of configurations. As one non-limiting example, the sensing elements may be arranged in an array. Each sensing element may capture a fingerprint image element  216  by measuring the capacitance between a portion of the finger overlying the sensing element. If the portion of the finger is farther away, as is the case with a valley of a fingerprint, the measured capacitance is generally lower than if the portion of the finger is closer to the sensing element, as is the case with a fingerprint ridge. 
     The fingerprint image elements may be combined to form a block  214 , and a set of blocks representing adjacent portions of a fingerprint may be combined into an image  212 . When combined with fixed pattern noise, damage  120  to a finger or fingerprint may cause one or more image elements  216  to be inaccurate representations of the corresponding portion of a fingerprint. These image elements may be fully black or fully white, for example. In some embodiments, fixed pattern noise alone is sufficient to cause errors in certain image elements  216 , regardless of the presence or absence of damage  120  to the stratum corneum  118 . Likewise, dryness or other characteristics of a user&#39;s finger may combine with fixed pattern noise to generate inaccurate image elements  216 . 
     Returning to  FIG. 1 , the sensor operation will be discussed in more detail. The sensor  122  may include an array of sensor elements  124 , each of which can provide an analog signal describing a relative depth of the layer of live skin  116  above the sensor elements  124 . This can have the effect that the sensor provides a set of signals, each of which indicates an individual fingerprint image element  216 . Each of the set of signals corresponds to, or is generated by, an individual sensor element  124 . It should be appreciated that the sensor elements  124  may be arranged in a grid or array, in a line, or in any other suitable pattern. Accordingly, embodiments discussed herein may be used with swipe sensors, two-dimensional sensors, and the like. 
     In one embodiment, a multiplexer  142  collects the analog signals from the sensor elements  124  of the sensor  122 , and multiplexes them together into sets of eight fingerprint image element signals. For example, each set of eight fingerprint image element signals can be collected into a set of eight channels of fingerprint image element signals. 
     In one embodiment, the fingerprint image element signals are coupled to one or more amplifiers  144 . The amplifiers  144  receive relatively weak signals, and amplify them to become relatively stronger signals. For example, the amplifiers  144  can increase the dynamic range of the fingerprint image element signals so they cover the scope of possible relative strength. 
     In one embodiment, a set of outputs from the amplifiers  144  are coupled to inputs of a corresponding set of A/D converters  146 . The A/D converters  146  receive analog input signals and generate digital output signals representing the same relative strength. This can have the effect of providing a set of digital signals  148 . For example, the digital signals  148  can each describe an eight-bit representation of a fingerprint image element. In such examples, that eight-bit representation can describe an unsigned integer grayscale value, such as between 0 and 255. 
     In one embodiment, the amplifiers  144  and the corresponding A/D converters  146  can have the effect of providing a multi-bit grayscale value describing a degree to which the corresponding fingerprint image element  216  is closer to black or to white. For example, in one encoding schema, an eight-bit grayscale value includes a decimal 0 (hexadecimal “00”) value describing a black fingerprint image element  216 , a decimal  255  (hexadecimal “FF”) value describing a white fingerprint image element  216 , and decimal values in between describing fingerprint image element  216  with distinct shades of gray. In further embodiments any suitable encoding schema, such as 10-bit encoding, may be used. 
     In one embodiment, the digital signals  148  collectively may be processed to provide a fingerprint image  212 , which is shown in the figure as having a set of ridges or ridge-lines, and possibly having one or more regions  150  that are either overexposed or underexposed in response to existence of damage  120  to the outer layer of the stratum corneum. 
     For a first example, it might occur that the fingerprint sensor system can successfully determine whether the fingerprint image  212  definitively matches or definitively does not match any known fingerprint information in the fingerprint information database, despite the presence of the overexposed or underexposed region  150 . In such cases, the fingerprint sensor system can inform the processing unit to authorize usage of the device (or refuse to authorize usage of the device) in response thereto, without further manipulation of the fingerprint image  212 . 
     For a second, non-limiting example, it might occur that the fingerprint sensor system cannot determine whether or not the fingerprint image  212  definitively matches or definitively does not match any known fingerprint information in the fingerprint information database, in response to the presence of the overexposed or underexposed region  150 . In such cases, the fingerprint sensor system can perform further manipulation of the fingerprint image  212 . This can have the effect that the fingerprint sensor system can obtain additional information that would allow it to make a definitive decision with respect to whether the fingerprint image  212  matches or does not match any known fingerprint information in the fingerprint information database. It should be appreciated, however, that imaging techniques disclosed herein may be used under a variety of circumstances and at a variety of times, as discussed later. 
     Fingerprint Imaging 
       FIG. 2  shows a conceptual drawing of fingerprint image, which will be discussed in more detail. 
     A fingerprint image  212  can include a set of image tiles  214 , each of which represents a portion of the fingerprint image  212 . For example, each image tile  214  can include an eight-bit by eight-bit portion of the fingerprint image  212 , and the fingerprint image  212  can include an 88 bit by 88 bit set of fingerprint image elements  216 . 
     As described herein, the fingerprint image  212  can include one or more overexposed or underexposed (e.g., poorly imaged) regions  150 , such as might be caused by damage  120  to the outer layer of the stratum corneum, the layer of dead skin  118 . As described herein, fingerprint information with respect to the user&#39;s finger  114  is affected by a thickness of the layer of dead skin  118 , with the consequence that the fingerprint information might be overexposed or underexposed due to the particular choice of amplifier gain and/or fixed pattern noise associated with the sensor. The poorly imaged region  150  may cause errors in identification of a user based on the fingerprint image, such as, but not limited to, false negatives. 
     In order to overcome poorly imaged regions  150 , a variety of techniques may be used. As one example, the fingerprint sensor system can take multiple images of the user&#39;s finger  114 . These multiple images can be taken in sequence or in parallel. The images may be taken one after another temporally or may be offset from one another along a physical axis and captured simultaneously. As one example, the individual sensor elements  124  making up the fingerprint sensor  122  may be arranged in a pattern defining two sub-sensors. For example, the individual sensor elements  124  may be split into two groups, such that each group belongs to a different sub-sensor. The sub-sensors may be interwoven with one another, like squares on a chessboard—each alternating element may belong to a different sub-sensor. Thus, the sub-sensors may simultaneously image a finger with different gain settings, and the “best” (e.g., non-saturated or least saturated) image may be chosen from those captured by two adjacent sensor elements  124 , each of which is associated with a different sub-sensor, and used. 
     It should be appreciated that the individual sensor elements  124  may be split into multiple groups or sub-sensors and not just two. Likewise, the geometry of each sub-sensor may vary between embodiments and sub-sensors need not have identical geometries. As one non-limiting example, the sensor elements  124  may be split into alternating rows or columns instead of a checkerboard pattern. 
     As another option, the sub-sensors may each image a finger at a different gain setting. The image elements  216  captured by each sub-sensor may be composited together to form a block  214  or image  212 , rather than discarding certain image elements  216 . In this fashion, each image element  216  may be formed from a composite of two or more sensor element  124  readings, and thus the saturation and/or effect of fixed pattern noise on any individual image element  216  may be reduced or negated. 
     In yet another embodiment, there may be no sub-sensors. Rather, all of the sensor elements  124  may be part of a single fingerprint sensor  122 . That fingerprint sensor  122  may capture multiple, temporally separated images of a user&#39;s fingerprint. Each of the temporally separated images may be captured at a different signal conditioning settings. In other words, conditioning may be applied differently to each temporally separated image so that one image may be the result of gain conditioning, while another image may be the result of offset conditioning. Any appropriate signal adaptation or clarification technique may apply separately or consistently to each temporally separated image; gain adjustment or conditioning is but one example. By way of example, signal conditioning setting # 1  may be used to capture image # 1 , while signal conditioning setting # 2  may be used to capture image # 2 . The gain for each sensor element  124  may be the same in any given signal conditioning setting, or the gains may vary (as is true for all embodiments discussed herein). Regardless, the temporally separated images may be composited to form a single fingerprint image  212 , such that no image element  216  is either fully saturated or completely white. 
     The various fingerprint imaging techniques described herein may be used in a variety of situations. For example, an embodiment may employ one or more of the techniques discussed herein based on a failure to match an imaged fingerprint to an image stored in memory. This may be relatively complex, and thus may require a relatively large processing unit and sizable amount of processing time during imaging and/or matching. 
     As another option, techniques disclosed herein may be used whenever a captured fingerprint image is of inferior or unacceptable quality. Embodiments may analyze the quality of the fingerprint image upon or after capture, and implement one or more of the techniques herein if the analysis indicates the image quality is unacceptable. It should be appreciated that the “quality” of an image may vary with its intended or actual use, parameters of an imaging and/or matching system, user-defined or programming-defined parameters, and the like. 
     As a third option, one or more techniques disclosed herein may be implemented constantly, by default, or whenever an image is captured. Such implementation may be performed by the hardware of the fingerprint sensor itself or by the direction of a processing unit. 
     Expanding on this example, the fingerprint sensor system can select distinct sets of individual fingerprint image elements  216  and combine them into a conflated fingerprint image  212 . In a first set of such cases, the fingerprint sensor system can select those tiles  214  that have the “best” (as determined by the fingerprint sensor system) fingerprint image data, and combine those individual tiles into a single fingerprint image  212 . In a second set of such cases, the fingerprint sensor system can determine how to match ridges or ridge lines of fingerprint image data at edges of those tiles  214  that have differing amplifier gain, such as attempting to blend fingerprint image elements  216  at the edges of those tiles  214 , or such as averaging fingerprint image elements  216  with some small overlap at the edges of those tiles  214 . 
     For a further example, the fingerprint sensor system can select only those portions of the fingerprint image  212  that are overexposed or underexposed, and re-image only those portions of the fingerprint image  212 . In a first such case, those portions of the fingerprint image  212  that are overexposed or underexposed can be identified by an excessive amount of low-frequency components, which would indicate that the selected portion is “whited out”, that is, overexposed. Alternatively, an excessive amount of high-frequency components in a signal from any single channel may indicate that the corresponding image element  216  is “blacked out”, that is, underexposed. Those particular image elements  216  may be selectively resampled at a different gain while the other image elements are not. Thus, only the sensing elements  124  corresponding to the image elements  216  being resampled need be reactivated and re-read. This may save power and time by minimizing the amount of resampling. 
     Resampling may be further minimized or reduced over the foregoing by certain embodiments. Some embodiments may selectively analyze an image not only to determine if a portion of the image should be resampled, but also may analyze whether or not resampling at a different gain may produce a better image element  216 . The embodiment, for example through operation of a processing unit, may analyze localized high frequency content in any given image element  216  and/or in adjacent image elements. This analysis may reveal that a different signal conditioning setting may de-saturate a given image element  216 . For example, if adjacent image elements are not fully saturated or near-saturated, changing the gain of a sensor element  124  producing a fully saturated image element  216  may permit the finger portion to be re-imaged and detail captured. A similar analysis may also be performed for any image element  216  that is pure white (e.g., fully desaturated). 
     For yet another example, the fingerprint sensor system can perform re-imaging in parallel, such as attempting to make multiple images concurrently or simultaneously, or in some other manner. In a first set of such cases, the fingerprint sensor system can include multiple copies of hardware used for making fingerprint images  212 , such as coupling the multiplexer  142  to more than one amplifier  144 , with the effect of providing more than one amplified copy of the fingerprint image data (each using distinct amplification gain). In a second set of such cases, the fingerprint sensor system can include one or more amplifiers  144 , at least one of which includes multiple stages, with outputs provided at more than one of the stages, with the effect of providing more than one signal, each with distinct amplifier gain. 
     Gain Control 
       FIG. 3  shows a conceptual drawing of a method of operation providing gain control for each of the signals corresponding to one of the sensor elements  124  of the fingerprint sensor  122 . Such gain control may be used with any of the embodiments described herein, and particularly with method and structures described above in the section titled “Fingerprint Imaging.” 
     A method  300  includes a set of flow points and method steps. Although these flow points and method steps are shown performed in a particular order, in the context of the invention, there is no particular requirement for any such limitation. For example, the flow points and method steps could be performed in a different order, concurrently, in parallel, or otherwise. 
     Although these flow points and method steps are sometimes described as being performed by the method  300 , in one embodiment, they can be performed by a processing unit in the device, or by hardware provided for the fingerprint sensor system. Although these flow points and method steps are described as performed by a general-purpose processing unit, in the context of the invention, there is no particular requirement for any such limitation. For example, one or more such method steps could be performed by special purpose processing unit, by another circuit, or be offloaded to other processing units or other circuits in other devices, such as by offloading those functions to nearby devices using wireless technology or by offloading those functions to cloud computing functions. Likewise, a “processing unit,” as used herein, may be a state machine, micro-controller, processor, logical element or set of elements, and the like. Any processing unit mentioned herein may be embedded in or with an associated fingerprint sensor (for example, implemented as part of the same silicon), embedded or associated with another electronics package or element, such as a system on a chip or the like, or may be discrete and/or dedicated to operations regarding fingerprint sensing. 
     At a flow point  300 A, the method  300  is ready to begin. At a step  312 , the method  300  attempts to image (or re-image) the information associated with the fingerprint image  212 . As described herein, when the method  300  attempts to image the information associated with the fingerprint image  212 , it attempts to collect sensor information with respect to the user&#39;s finger  114 . 
     For example, as described above, this step can be performed by hardware provided for the fingerprint sensor system, or by a processing unit provided in the device associated with the fingerprint sensor system (whether a general-purpose processing unit, a special-purpose processing unit, or a processing unit in association with other hardware elements). 
     In one embodiment, when the method  300  attempts to initially image the information associated with the fingerprint image  212 , it associates an amplification gain with the amplifier  144 . For example, when the method  300  attempts to initially image the information, it can start with an initial amplification gain, such as an amplification gain likely to work with most users&#39; fingers, or an amplification gain that most recently worked. 
     In one embodiment, when the method  300  attempts to re-image the information associated with the fingerprint image  212 , that is, to image that information a second or later time, it uses a new amplification gain with the amplifier  144 . For example, as described below, when the method  300  adjusts the amplification gain for the amplifier  144 . the method  300  uses that new amplification gain. 
     At a step  314 , the method  300  attempts to match information in the fingerprint information database with the fingerprint image from the captured fingerprint image. As described herein, if the method  300  is able to make a definitive decision that there is a match, or that there is not a match, between the captured fingerprint image and one or more known user fingerprints, 
     At a step  316 , the method  300  determines whether it was successful in making a definitive match-or-no-match decision. If there was a definitive match-or-no-match decision, the method  300  proceeds with the step  318 . At the step  318 , the method  300  proceeds without any requirement to gather further information. After the step  318 , the method  300  proceeds with the flow point  300 B, where the method  300  ends. In an alternative embodiment, if it is determined that a match cannot be made, operation  320  may be executed in order to re-image the finger and recapture a fingerprint with different operating parameters for the fingerprint sensor. 
     At a step  320 , the method  300  determines whether it is possible to further adjust the amplification gain for the amplifier  144 . For example, it might occur that the method  300  has tried all possible amplification gain values, or has maximized the possible amplification gain (when additional gain is employed), or has minimized the possible amplification gain (when less gain is used). If is not possible to further adjust the amplification gain, the method  300  proceeds with the step  322 . At the step  322 , the method  300  proceeds as if it was unable to obtain sufficient captured fingerprint image. When there is nothing the method  300  can do to obtain further captured fingerprint image, the method  300  proceeds as if the match failed. After the step  322 , the method  300  proceeds with the flow point  300 B, where the method  300  ends. 
     At a step  324 , the method  300  adjusts (or further adjusts, as appropriate) the amplification gain for the amplifier  144 . For example, if the region  150  is overexposed, the method  300  can decrease the amplification gain, while if the region  150  is underexposed, the method  300  can increase the amplification gain. After the step  324 , the method  300  proceeds with the step  312 , where it attempts to re-image the information associated with the fingerprint image  212 . 
     At a flow point  300 B, the method  300  is over. In one embodiment, the method  300  repeats so long as the device is powered on. 
     Further, method  300  is not the sole method of operation for fingerprint sensors described herein. As previously mentioned, imaging methodologies may be employed constantly and applied to every captured image, or at least whenever any image is captured. Alternatively, and as discussed above, imaging methodologies disclosed herein may be used whenever a captured fingerprint image is of an unacceptable quality, or when a captured fingerprint image cannot be matched. Accordingly, the flowchart shown in  FIG. 3  is but one method of operation for embodiments. 
     Histogram Determination and Segmentation 
       FIG. 4A  generally shows a histogram for a fingerprint image; the histogram may be operated upon as described herein to provide dynamic range scaling in order to more accurately image a fingerprint and extract data from the image. In some embodiments, such dynamic range scaling or adjustment may compensate for fixed pattern noise. 
     In one embodiment, the outputs from the A/D converters  146  can be extended to provide additional bits of discrimination between distinct shades of gray. For example, more than eight bits of grayscale value can be determined in response to an analog signal coupled from the amplifiers  144  to their corresponding A/D converters  146 . 
     In one embodiment, as each fingerprint image tile  214  is being determined, the processing unit (as described herein) reviews the digital signals  148 , determining a histogram  452 , relating a grayscale value (shown in the figure on an X axis  454 ) with a number of fingerprint picture elements  216  (shown in the figure on a Y axis  456 ). The histogram  452  can often include a relatively significant peak  458  in a relatively saturated region of the grayscale value axis  454 , and indicating that fixed pattern noise has affected the fingerprint image tile  214 . For example, the fingerprint image tile  214  can often include a relatively saturated vertical bar, in which substantially all of the fingerprint picture elements  216  have been saturated at measurement. 
     In one embodiment, the processing unit locates the peak  458 , removes that portion of the histogram  452  with respect to the peak  458 , and divides the histogram  452  into two (or more) portions. Although the method  400  is described with respect to two portions, in the context of the invention, there is no particular requirement for any such limitation. For example, the histogram can be divided into three or more portions, although it might be superior to choose the number of portions as four, eight, or another power of two. 
     In one embodiment, having divided the histogram  452  into two portions, the processing unit sets two (independently controllable) amplifiers  144  so that a lower half  452   a  of the histogram can be amplified to a full scale of a corresponding A/D converter  146 , and an upper half  452   b  of the histogram can also be amplified to a full scale of a corresponding A/D converter  146 . The lower half  452   a  of the histogram  452  can be coupled to a corresponding A/D converter  146 , providing a selected number of shades of gray, with a corresponding log-base-two bits of grayscale data for each fingerprint image element  216 . Similarly, the upper half  452   b  of the histogram  452  can be coupled to a corresponding A/D converter  146 , providing a selected number of shades of gray, with its own corresponding log-base-two bits of grayscale data for each fingerprint image element  216 . 
     With both the grayscale data from the lower half  452   a  and the grayscale data from the upper half  452   b , the values from the two corresponding A/D converters  146  can be combined, with the effect of providing twice as many shades of gray, or one additional bit of grayscale data for each fingerprint image element  216 . This can be performed for each fingerprint image tile  214 , with respect to the fingerprint image elements  216  associated with that fingerprint image tile  214 . In alternative embodiments, this can be performed for the entire fingerprint image  212 , with respect to the fingerprint image elements  216  associated with the fingerprint image  212 , although the former is believed likely to be superior. 
     In embodiments wherein the histogram  452  is divided into more than two parts, such as four parts or eight parts, there would be a correspondingly larger number of independently controllable amplifiers  144  and an equivalently larger number of corresponding A/D converters  146 . However, in alternative embodiments, it may occur that the histogram  452  can be divided into two or more parts, the individual parts multiplexed using the same hardware amplifiers  144  and A/D converters  146 , and the results combined. 
     In one embodiment, as described herein, there may be two amplifiers  144  corresponding to each fingerprint image tile  214 , such as a first amplifier  144  to be used with the lower half  452   a  of the histogram  452  and a second amplifier  144  to be used with the upper half  452   b  of the histogram  452 . In embodiments in which the histogram  452  is divided into more than two portions, there may be more than two such amplifiers  144 . In alternative embodiments, as described herein, the signals input to the amplifier  144  may be multiplexed, operated upon separately for each portion of the histogram  452  by each such amplifier  144 , and combined, as described herein. Similarly, in embodiments in which the histogram  452  is divided into more than two portions, there may be more than two such A/D converters  146 , one corresponding to each such amplifier  144 , or alternatively, the signals that are multiplexed with respect to each amplifier  144  may be multiplexed, operated upon separately for each portion of the histogram  452  by each such A/D converter  146 , and combined, as described herein. 
     A method  400  for histogram scaling, and corresponding dynamic range scaling, is shown generally in  FIG. 4B  and includes a set of flow points and method steps. Although these flow points and method steps are shown performed in a particular order, in the context of the invention, there is no particular requirement for any such limitation. For example, the flow points and method steps could be performed in a different order, concurrently, in parallel, or otherwise. 
     Likewise, although these flow points and method steps are sometimes described as being performed by the method  300 , in one embodiment, they can be performed by a processing unit in the device, or by hardware provided for the fingerprint sensor system. Although these flow points and method steps are described as performed by a general-purpose processing unit, in the context of the invention, there is no particular requirement for any such limitation. For example, one or more such method steps could be performed by special purpose processing unit, by another circuit, or be offloaded to other processing units or other circuits in other devices, such as by offloading those functions to nearby devices using wireless technology or by offloading those functions to cloud computing functions. 
     The second method  400  can be performed in addition to the first method  300 . The second method  400  can also be performed optionally. 
     At a flow point  400 A, the method  400  is ready to begin. 
     At a step  412 , the method  400  determines a histogram  452  for each fingerprint image tile  214 . In one embodiment, the histogram  452  can have 256 separate bins for grayscale values; however, in the context of the invention, there is no particular requirement for any such limitation. For example, in alternative embodiments, the histogram  452  may include some larger or smaller number of shades of gray. 
     At a step  414 , the method  400  determines a peak  458  for the histogram  452 , as described herein, located at one end of the histogram  452 , indicating cases in which the fingerprint image elements  216  have been maximized or minimized by fixed pattern noise, such as black bars or white bars. 
     At a step  416 , the method  400  removes the peak  458  from the histogram  452 . For example, the method  400  can set those bins that it determines are part of the peak  458  to have no fingerprint image elements  216 . 
     At a step  418 , the method  400  divides the histogram  452  into a lower portion  452   a  and an upper portion  452   b , at a dividing point  460 . In alternative embodiments, in which there are more than two such portions, the method  400  divides the histogram  452  into more than two such portions. For example, the method  400  can determine a median point of the histogram  452 , at which the number of fingerprint image elements  216  below that median point equals the number of fingerprint image elements  216  above that median point. Alternatively, the method  400  can determine a half-way point, at an average of the highest and lowest (significantly populated) bin of the histogram  452 , or an average grayscale value, at an average shade of gray described by the histogram  452  after its peak  458  has been removed. 
     At a step  420 , the method  400  independently controls a lower-half amplifier  144  and an upper-half amplifier  144 , as described herein. In one embodiment, those portions of the signal that would eventually represent those fingerprint image elements  216  in the lower portion  452   a  of the histogram  452  are amplified by the lower-half amplifier  144  to an entire range of its corresponding A/D converter  146 . Similarly, those portions of the signal that would eventually represent those fingerprint image elements  216  in the upper portion  452   a  of the histogram  452  are amplified by the upper-half amplifier  144  to an entire range of its corresponding A/D converter  146 . 
     In one embodiment, the method  400  controls the lower-half amplifier  144  and the upper-half amplifier  144  so that there is no substantial gap or overlap. However, in the context of the invention, there is no particular requirement for any such limitation. For a first example, the method  400  may control the lower-half amplifier  144  and the upper-half amplifier  144  so that there is a minimal gap or a minimal overlap. For a second example, the method  400  may control the lower-half amplifier  144  and the upper-half amplifier  144  so that a maximum amount of grayscale information can be provided. 
     At a step  422 , the method  400  receives the results of the corresponding A/D converters  146  associated with the lower-half amplifier  144  and the upper-half amplifier  144 . As part of this step, the method  400  combines those results. For example, the method  400  can prepend a bit “0” to the results from the A/D converter  146  associated with the lower-half amplifier  144 , and prepend a bit “1” to the results from the A/D converter  146  associated with the upper-half amplifier  144 . A result of this step can be provided by the method  400  as a set of fingerprint picture elements  216  with superior dynamic range. 
     At a flow point  400 B, the method  400  is over. In one embodiment, the method  400  repeats so long as the device is powered on. 
     Touch I/O Device Including Fingerprint Recognition System 
       FIG. 5  (collectively including  FIG. 5A  and  FIG. 5B ) shows a conceptual drawing of a touch I/O device including a fingerprint recognition system. 
     A touch I/O electronic device or system  1000  can include a touch-sensitive input/output (touch I/O) device  1006  in communication with computing system  1008  via communications channel  1010 . 
     Described embodiments may include touch I/O device  1006  that can receive touch input for interacting with computing system  1008  via wired or wireless communication channel  1002 . Touch I/O device  1006  may be used to provide user input to computing system  1008  in lieu of or in combination with other input devices such as a keyboard, mouse, etc. One or more touch I/O devices  1001  may be used for providing user input to computing system  1008 . Touch I/O device  1006  may be an integral part of computing system  1008  (e.g., touch screen on a laptop) or may be separate from computing system  1008 . 
     For example, touch I/O device  1006  can interact with a user with the user touching the touch I/O device  1006  with the user&#39;s finger (or otherwise bringing the user&#39;s finger near to the touch I/O device  1006 ), with the effect that the touch I/O device  1006  can receive fingerprint image data, and optionally provide feedback to the user that the fingerprint image data was received. 
     Touch I/O device  1006  may include a touch sensitive panel which is wholly or partially transparent, semitransparent, non-transparent, opaque or any combination thereof. Touch I/O device  1006  may be embodied as a touch screen, touch pad, a touch screen functioning as a touch pad (e.g., a touch screen replacing the touchpad of a laptop), a touch screen or touchpad combined or incorporated with any other input device (e.g., a touch screen or touchpad disposed on a keyboard, disposed on a trackpad, or other pointing device) or any multi-dimensional object having a touch sensitive surface for receiving touch input, or another type of input device or input/output device. 
     In one example, touch I/O device  1006  embodied as a touch screen may include a transparent and/or semitransparent touch sensitive panel partially or wholly positioned over at least a portion of a display. According to this embodiment, touch I/O device  1006  functions to display graphical data transmitted from computing system  1008  (and/or another source) and also functions to receive user input. In other embodiments, touch I/O device  1006  may be embodied as an integrated touch screen where touch sensitive components/devices are integral with display components/devices. In still other embodiments a touch screen may be used as a supplemental or additional display screen for displaying supplemental or the same graphical data as a primary display and to receive touch input. 
     Touch I/O device  1006  may be configured to detect the location of one or more touches or near touches on device  1001  based on capacitive, resistive, optical, acoustic, inductive, mechanical, chemical measurements, or any phenomena that can be measured with respect to the occurrences of the one or more touches or near touches in proximity to device  1001 . Software, hardware, firmware or any combination thereof may be used to process the measurements of the detected touches to identify and track one or more gestures or fingerprints. A gesture or fingerprint may correspond to stationary or non-stationary, single or multiple, touches or near touches on touch I/O device  1006 . A gesture or fingerprint may be performed by moving one or more fingers or other objects in a particular manner on touch I/O device  1006  such as tapping, pressing, rocking, scrubbing, twisting, changing orientation, pressing with varying pressure and the like at essentially the same time, contiguously, or consecutively. A gesture or fingerprint may be characterized by, but is not limited to a pinching, sliding, swiping, rotating, flexing, dragging, or tapping motion between or with any other finger or fingers. A single gesture may be performed with one or more hands, by one or more users, or any combination thereof. 
     Computing system  1008  may drive a display with graphical data to display a graphical user interface (GUI). The GUI may be configured to receive touch input via touch I/O device  1006 . Embodied as a touch screen, touch I/O device  1006  may display the GUI. Alternatively, the GUI may be displayed on a display separate from touch I/O device  1006 . The GUI may include graphical elements displayed at particular locations within the interface. Graphical elements may include but are not limited to a variety of displayed virtual input devices including virtual scroll wheels, a virtual keyboard, virtual knobs, virtual buttons, any virtual UI, and the like. A user may perform gestures at one or more particular locations on touch I/O device  1006  which may be associated with the graphical elements of the GUI. In other embodiments, the user may perform gestures at one or more locations that are independent of the locations of graphical elements of the GUI. Gestures performed on touch I/O device  1006  may directly or indirectly manipulate, control, modify, move, actuate, initiate or generally affect graphical elements such as cursors, icons, media files, lists, text, all or portions of images, or the like within the GUI. For instance, in the case of a touch screen, a user may directly interact with a graphical element by performing a gesture over the graphical element on the touch screen. Alternatively, a touch pad generally provides indirect interaction. Gestures may also affect non-displayed GUI elements (e.g., causing user interfaces to appear) or may affect other actions within computing system  1008  (e.g., affect a state or mode of a GUI, application, or operating system). Gestures may or may not be performed on touch I/O device  1006  in conjunction with a displayed cursor. For instance, in the case in which gestures are performed on a touchpad, a cursor (or pointer) may be displayed on a display screen or touch screen and the cursor may be controlled via touch input on the touchpad to interact with graphical objects on the display screen. In other embodiments in which gestures are performed directly on a touch screen, a user may interact directly with objects on the touch screen, with or without a cursor or pointer being displayed on the touch screen. 
     Feedback may be provided to the user via communication channel  1010  in response to or based on the touch or near touches on touch I/O device  1006 . Feedback may be transmitted optically, mechanically, electrically, olfactory, acoustically, or the like or any combination thereof and in a variable or non-variable manner. For example, feedback can include interaction with a user indicating (A) that one or more sets of fingerprint image information have been received, (B) that one or more sets of fingerprint image information have been enrolled in a database, (C) that one or more sets of fingerprint image information have been confirmed as associated with the user, or otherwise. 
     Attention is now directed towards embodiments of a system architecture that may be embodied within any portable or non-portable device including but not limited to a communication device (e.g. mobile phone, smart phone), a multi-media device (e.g., MP3 player, TV, radio), a portable or handheld computer (e.g., tablet, netbook, laptop), a desktop computer, an All-In-One desktop, a peripheral device, or any other system or device adaptable to the inclusion of system architecture  2000 , including combinations of two or more of these types of devices. A block diagram of one embodiment of system  2000  generally includes one or more computer-readable mediums  2001 , processing system  2004 , Input/Output (I/O) subsystem  2006 , radio frequency (RF) circuitry  2008  and audio circuitry  2010 . These components may be coupled by one or more communication buses or signal lines  2003 . Each such bus or signal line may be denoted in the form  2003 -X, where X is a unique number. The bus or signal line may carry data of the appropriate type between components; each bus or signal line may differ from other buses/lines, but may perform generally similar operations. 
     It should be apparent that the architecture shown in the figure is only one example architecture of system  2000 , and that system  2000  could have more or fewer components than shown, or a different configuration of components. The various components shown in the figure can be implemented in hardware, software, firmware or any combination thereof, including one or more signal processing and/or application specific integrated circuits. 
     RF circuitry  2008  is used to send and receive information over a wireless link or network to one or more other devices and includes well-known circuitry for performing this function. RF circuitry  2008  and audio circuitry  2010  are coupled to processing system  2004  via peripherals interface  2016 . Interface  2016  includes various known components for establishing and maintaining communication between peripherals and processing system  2004 . Audio circuitry  2010  is coupled to audio speaker  2050  and microphone  2052  and includes known circuitry for processing voice signals received from interface  2016  to enable a user to communicate in real-time with other users. In some embodiments, audio circuitry  2010  includes a headphone jack (not shown). 
     Peripherals interface  2016  couples the input and output peripherals of the system to processor  2018  and computer-readable medium  2001 . One or more processors  2018  communicate with one or more computer-readable mediums  2001  via controller  2020 . Computer-readable medium  2001  can be any device or medium that can store code and/or data for use by one or more processors  2018 . Medium  2001  can include a memory hierarchy, including but not limited to cache, main memory and secondary memory. The memory hierarchy can be implemented using any combination of RAM (e.g., SRAM, DRAM, DDRAM), ROM, FLASH, magnetic and/or optical storage devices, such as disk drives, magnetic tape, CDs (compact disks) and DVDs (digital video discs). Medium  2001  may also include a transmission medium for carrying information-bearing signals indicative of computer instructions or data (with or without a carrier wave upon which the signals are modulated). For example, the transmission medium may include a communications network, including but not limited to the Internet (also referred to as the World Wide Web), intranet(s), Local Area Networks (LANs), Wide Local Area Networks (WLANs), Storage Area Networks (SANs), Metropolitan Area Networks (MAN) and the like. 
     One or more processors  2018  run various software components stored in medium  2001  to perform various functions for system  2000 . In some embodiments, the software components include operating system  2022 , communication module (or set of instructions)  2024 , touch processing module (or set of instructions)  2026 , graphics module (or set of instructions)  2028 , one or more applications (or set of instructions)  2030 , and fingerprint sensing module (or set of instructions)  2038 . Each of these modules and above noted applications correspond to a set of instructions for performing one or more functions described above and the methods described in this application (e.g., the computer-implemented methods and other information processing methods described herein). These modules (i.e., sets of instructions) need not be implemented as separate software programs, procedures or modules, and thus various subsets of these modules may be combined or otherwise rearranged in various embodiments. In some embodiments, medium  2001  may store a subset of the modules and data structures identified above. Furthermore, medium  2001  may store additional modules and data structures not described above. 
     Operating system  2022  includes various procedures, sets of instructions, software components and/or drivers for controlling and managing general system tasks (e.g., memory management, storage device control, power management, etc.) and facilitates communication between various hardware and software components. 
     Communication module  2024  facilitates communication with other devices over one or more external ports  2036  or via RF circuitry  2008  and includes various software components for handling data received from RF circuitry  2008  and/or external port  2036 . 
     Graphics module  2028  includes various known software components for rendering, animating and displaying graphical objects on a display surface. In embodiments wherein touch I/O device  2012  is a touch sensitive display (e.g., touch screen), graphics module  2028  includes components for rendering, displaying, and animating objects on the touch sensitive display. 
     One or more applications  2030  can include any applications installed on system  2000 , including without limitation, a browser, address book, contact list, email, instant messaging, word processing, keyboard emulation, widgets, JAVA-enabled applications, encryption, digital rights management, voice recognition, voice replication, location determination capability (such as that provided by the global positioning system (GPS)), a music player, etc. 
     Touch processing module  2026  includes various software components for performing various tasks associated with touch I/O device  2012  including but not limited to receiving and processing touch input received from I/O device  2012  via touch I/O device controller  2032 . 
     System  2000  may further include fingerprint sensing module  2038  for performing the method/functions as described herein in connection with figures as shown herein. Fingerprint sensing module  2038  may at least function to perform various tasks associated with the fingerprint sensor, such as receiving and processing fingerprint sensor input. The fingerprint sensing module  2038  may also control certain operational aspects of the fingerprint sensor  2042 , such as its capture of fingerprint data and/or transmission of the same to the processor  2018  and/or secure processor  2040 . Both processor  2018  and secure processor  2040  are examples of processing units, and it should be appreciated that one or both may be multi-core and/or multi-chip elements in some embodiments. Module  2038  may also interact with the touch I/O device  2012 , graphics module  2028  or other graphical display. Module  2038  may be embodied as hardware, software, firmware, or any combination thereof. Although module  2038  is shown to reside within medium  2001 , all or portions of module  2038  may be embodied within other components within system  2000  or may be wholly embodied as a separate component within system  2000 . 
     I/O subsystem  2006  is coupled to touch I/O device  2012  and one or more other I/O devices  2014  for controlling or performing various functions. Touch I/O device  2012  communicates with processing system  2004  via touch I/O device controller  2032 , which includes various components for processing user touch input (e.g., scanning hardware). One or more other input controllers  2034  receives/sends electrical signals from/to other I/O devices  2014 . Other I/O devices  2014  may include physical buttons, dials, slider switches, sticks, keyboards, touch pads, additional display screens, or any combination thereof. 
     If embodied as a touch screen, touch I/O device  2012  displays visual output to the user in a GUI. The visual output may include text, graphics, video, and any combination thereof. Some or all of the visual output may correspond to user-interface objects. Touch I/O device  2012  forms a touch-sensitive surface that accepts touch input from the user. Touch I/O device  2012  and touch screen controller  2032  (along with any associated modules and/or sets of instructions in medium  2001 ) detects and tracks touches or near touches (and any movement or release of the touch) on touch I/O device  2012  and converts the detected touch input into interaction with graphical objects, such as one or more user-interface objects. In the case in which device  2012  is embodied as a touch screen, the user can directly interact with graphical objects that are displayed on the touch screen. Alternatively, in the case in which device  2012  is embodied as a touch device other than a touch screen (e.g., a touch pad), the user may indirectly interact with graphical objects that are displayed on a separate display screen embodied as I/O device  2014 . 
     Touch I/O device  2012  may be analogous to the multi-touch sensitive surface described in the following U.S. patents: U.S. Pat. No. 6,323,846 (Westerman et al.), U.S. Pat. No. 6,570,557 (Westerman et al.), and/or U.S. Pat. No. 6,677,932 (Westerman), and/or U.S. Patent Publication 2002/0015024A1, each of which is hereby incorporated by reference. 
     Embodiments in which touch I/O device  2012  is a touch screen, the touch screen may use LCD (liquid crystal display) technology, LPD (light emitting polymer display) technology, OLED (organic LED), or OEL (organic electro luminescence), although other display technologies may be used in other embodiments. 
     Feedback may be provided by touch I/O device  2012  based on the user&#39;s touch input as well as a state or states of what is being displayed and/or of the computing system. Feedback may be transmitted optically (e.g., light signal or displayed image), mechanically (e.g., haptic feedback, touch feedback, force feedback, or the like), electrically (e.g., electrical stimulation), olfactory, acoustically (e.g., beep or the like), or the like or any combination thereof and in a variable or non-variable manner. 
     System  2000  also includes power system  2044  for powering the various hardware components and may include a power management system, one or more power sources, a recharging system, a power failure detection circuit, a power converter or inverter, a power status indicator and any other components typically associated with the generation, management and distribution of power in portable devices. 
     In some embodiments, peripherals interface  2016 , one or more processors  2018 , and memory controller  2020  may be implemented on a single chip, such as processing system  2004 . In some other embodiments, they may be implemented on separate chips. 
     In addition to the foregoing, the system  2000  may include a secure processor  2040  in communication with a fingerprint sensor  2042 , via a fingerprint I/O controller  2044 . The operation of these various elements will now be described. 
     The fingerprint sensor  2042  may operate to capture a series of images, or nodes. When taken together, these nodes may form a set of fingerprint image information. A collection of nodes may be referred to herein as a “mesh”, “mosaic”, “template”, or other indicator of fingerprint information. 
     Each node of fingerprint information may be separately captured by the fingerprint sensor  2042 , which may be an array sensor. Generally, there is some overlap between images in nodes representing adjacent portions of a fingerprint. Such overlap may assist in assembling the fingerprint from the nodes, as various image recognition techniques may be employed to use the overlap to properly identify and/or align adjacent nodes in the fingerprint information. 
     Sensed fingerprint data may be transmitted through the fingerprint I/O controller  2044  to the processor  2018  and/or the secure processor  2040 . In some embodiments, the data is relayed from the fingerprint I/O controller  2044  to the secure processor  2040  directly. Generally, the fingerprint data is encrypted by any of the fingerprint sensor  2042 , the fingerprint I/O controller  2044  or another element prior to being transmitted to either processor. The secure processor  2040  may decrypt the data to reconstruct the node. 
     Fingerprint data may be stored in the computer-readable medium  2001  and accessed as necessary. In some embodiments, only the secure processor  2040  may access stored fingerprint data, while in other embodiments either the secure processor or the processor  2018  may access such data. 
     While this invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes can be made and equivalents may be substituted for elements thereof, without departing from the spirit and scope of the invention. In addition, modifications may be made to adapt the teachings of the invention to particular situations and materials, without departing from the essential scope thereof. Thus, the invention is not limited to the particular examples that are disclosed herein, but encompasses all embodiments falling within the scope of the appended claims.

Metadata:
Filing Date: 20130315
Publication Date: 20180904
Grant Date: 20180904
Priority Date: 20130315
Inventors: LYON, BENJAMIN B.
GOZZINI, GIOVANNI
Assignee: APPLE INC
CPC Classifications: [{"code": "G06V40/1347", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06V40/1306", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V10/98", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V10/30", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06K9/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06K9/00067", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06K9/0002", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06K9/03", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V10/98", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V40/1306", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V10/30", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V40/1347", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 51525619