CN105913049A - Fingerprint collection device - Google Patents
Fingerprint collection device Download PDFInfo
- Publication number
- CN105913049A CN105913049A CN201610345417.0A CN201610345417A CN105913049A CN 105913049 A CN105913049 A CN 105913049A CN 201610345417 A CN201610345417 A CN 201610345417A CN 105913049 A CN105913049 A CN 105913049A
- Authority
- CN
- China
- Prior art keywords
- voltage
- mode
- fingerprint
- number converter
- mode number
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
- G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
- G06V40/12—Fingerprints or palmprints
- G06V40/13—Sensors therefor
- G06V40/1306—Sensors therefor non-optical, e.g. ultrasonic or capacitive sensing
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2218/00—Aspects of pattern recognition specially adapted for signal processing
- G06F2218/02—Preprocessing
- G06F2218/04—Denoising
Landscapes
- Engineering & Computer Science (AREA)
- Human Computer Interaction (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Multimedia (AREA)
- Theoretical Computer Science (AREA)
- Image Input (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
The embodiment of the invention discloses a fingerprint collection device, which comprises a fingerprint sensing array, an adjustable gain amplifier, a common mode voltage compensation circuit, a voltage analog to digital converter and a signal processing unit, wherein the fingerprint sensing array is used for collecting fingerprint information to obtain voltage signals; the adjustable gain amplifier is used for amplifying the voltage signals to obtain amplifying signals; the common mode voltage compensation circuit is used for compensating voltage for the amplifying signals to eliminate common mode voltage and noise in the amplifying signals; the voltage analog to digital converter is used for converting the amplifying signals with the common mode voltage and the noise eliminated to digital signals; and the signal processing unit is used for acquiring an initial fingerprint image according to the digital signals and controlling parameters of the above adjustable gain amplifier, the common mode voltage compensation circuit and the voltage analog to digital converter based on the histogram of the initial fingerprint image. By adopting the device of the invention, a clear fingerprint image can be acquired in a condition in which a protection layer has non-uniform thickness and fingerprint differences between users are large.
Description
Technical field
The present invention relates to field of computer technology, particularly relate to a kind of fingerprint acquisition device.
Background technology
Refer to the structural representation that Fig. 1, Fig. 1 are a kind of fingerprint acquisition devices of the prior art, this fingerprint
Harvester includes protective layer, glue and fingerprint induction arrays, this fingerprint induction arrays (i.e. fingerprint collecting chip)
It is placed in below protective layer, is combined together by gluing in the middle of this protective layer and this fingerprint induction arrays.This refers to
Stricture of vagina harvester gathers the principle of fingerprint as in figure 2 it is shown, the metal electrode on finger and fingerprint induction arrays surface
Form parasitic capacitance.Owing to the valley and a ridge of finger is different to the distance of metal electrode, thus the parasitic electricity formed
Hold also different, such that it is able to reflect fingerprint graph by measuring parasitic capacitance.Owing to glue thickness is less, no
Consider the glue impact on parasitic capacitance.Parasitic capacitance (hereinafter referred to as finger electric capacity Cf) between finger and metal electrode
Expression formula is: Cf=(Cx*Cy)/(Cx+Cy),
Wherein, Cx=(ε _ 0* ε _ f*S)/df, Cy=(ε _ 0* ε _ x*S)/dx, Cx are finger between protective layer
Electric capacity, Cy is protective layer to the electric capacity between metal electrode, and S is electrode area, and dx is protective layer
Thickness, df is the finger surface distance to protective layer, and ε _ 0 is permittivity of vacuum, and ε _ x is protection
The dielectric constant of layer, ε _ f is the dielectric constant of finger and protection interlayer.
The inventor of the technical program finds in research process, due to the guarantor in existing fingerprint acquisition device
There is problem in uneven thickness when manufacturing in sheath and glue, and when protective layer out-of-flatness, gathers array
Cy is the most different everywhere, so migration noise can be formed, it is therefore desirable to offset migration noise.
Summary of the invention
The embodiment of the invention discloses a kind of fingerprint acquisition device, it is possible at the in uneven thickness of protective layer and
More clearly fingerprint image still can be obtained in the case of fingerprint differs greatly between user.
First aspect, embodiments provides a kind of fingerprint acquisition device, described fingerprint acquisition device bag
Include fingerprint induction arrays, variable gain amplifier, common-mode voltage compensation circuit, voltage-mode number converter and letter
Number processing unit, wherein:
Described fingerprint induction arrays, is used for gathering finger print information to obtain voltage signal, and is believed by described voltage
Number output to described variable gain amplifier；
Described variable gain amplifier, for amplifying described voltage signal to be amplified signal；
Described common-mode voltage compensates circuit, for believing described amplification signal compensation voltage to eliminate described amplification
Common-mode voltage in number and noise；
Described voltage-mode number converter, for receiving the amplification letter eliminating described common-mode voltage and described noise
Number, and the amplification signal eliminating described common-mode voltage and described noise is converted to digital signal；By described
Digital signal exports to described signal processing unit；
Described signal processing unit, for obtaining initial fingerprint image according to described digital signal, it is judged that described
It is pre-conditioned whether the rectangular histogram of initial fingerprint image meets；If being unsatisfactory for, then control to adjust described adjustable increasing
The amplification of benefit amplifier, the reference voltage of described voltage-mode number converter and described common-mode voltage compensate electricity
In the magnitude of voltage that road compensates at least one, until what described signal processing unit obtained according to described digital signal
The rectangular histogram of fingerprint image meets described pre-conditioned.
Specifically, the output of this fingerprint induction arrays is connected with the input of this variable gain amplifier, and this is adjustable
After the signal of the output that the signal of the output of gain amplifier compensates circuit with this common-mode voltage converges, with this electricity
The input of pressing mold number converter is connected, the output of this voltage-mode number converter and the input of this signal processing unit
Being connected, can also arrange and this variable gain amplifier, the common-mode voltage of this signal processing unit compensate circuit
Three paths being individually connected with voltage-mode number converter, for this variable gain amplifier, common-mode voltage
Compensate circuit and voltage-mode number converter is controlled.Further, it is also possible to this fingerprint induction arrays,
Variable gain amplifier, common-mode voltage compensate circuit, voltage-mode number converter and signal processing unit and are integrated in
In same special IC (Application Specific Integrated Circuits, ASIC), the most not
Disconnected can save material cost and can also shorten the time of fingerprint collecting as far as possible.
This fingerprint induction arrays can be semiconductor fingerprint sensor based on semiconductor silicon capacity effect technology,
This semiconductor fingerprint sensor includes quasiconductor pressure-sensitive sensor, conductor temperature inductive transducer, partly leads
Body capacitance formula fingerprint sensors etc., embodiment of the present invention emphasis is quasiconductor around this semiconductor fingerprint sensor
The situation of capacitive fingerprint sensing device is launched to describe.
This variable gain amplifier can include an amplifier element, it is also possible to includes multiple amplifier element, should
Amplifier element can be PNP type triode, NPN type triode etc., when there is multiple amplifier element, and should
Multiple amplifier elements can be connected.It should be noted that the amplification of this variable gain amplifier can root
It is adjusted according to needs in good time, such as, this variable gain amplifier is set to switched capacitor amplifier, this
Sample is once controlling the opening and closing of capacitance switch to control amplification.
This common-mode voltage compensates circuit and is used for exporting analog voltage signal, and this common-mode voltage compensates circuit can be had
Body is a D/A converting circuit, and common-mode voltage compensates the input of circuit and have input digital voltage signal
The outfan output analog voltage signal of circuit is compensated from this common-mode voltage.
This voltage-mode number converter can be production line analog-digital converter, it is also possible to for Approach by inchmeal analog digital conversion
Device, can also be other analog-digital converters certainly.Resolution Q of this voltage-mode number converter can be minimum
Significance bit (Least significant bit, LSB) voltage, in other words, the resolution of this voltage-mode number converter
Rate Q equal to the voltage measurement scope of this voltage-mode number converter divided by discrete voltage space-number, this voltage measurement
Scope is also full range voltage scope, and it is equal to the reference voltage of this voltage-mode number converter, and voltage spaces
The number M power equal to 2, M is the figure place of this voltage-mode number converter, so adjusting this voltage-mode number conversion
The reference voltage of device can regulate total voltage measurement scope of this voltage-mode number converter and dividing of output signal
Resolution.For example, if can the measuring in the range of 0v～10v of the voltage-mode number converter of 8,
Correspondingly resolution Q of output signal be equal to 10/2^8, i.e. 10/256.Further, this voltage modulus turns
The reference voltage of parallel operation can adjust the most in good time.
By running above-mentioned fingerprint acquisition device, this fingerprint acquisition device can be by signal processing unit to adopting
Collect to the rectangular histogram of fingerprint image be analyzed, it is judged that whether the voltage range of this fingerprint image drops into
Position appropriate in the range of the voltage measurement of this voltage analog to digital conversion circuit, if not falling under appropriate
Position then compensates circuit and voltage by this signal processing unit to this variable gain amplifier, this common-mode voltage
In analog-digital converter, at least one piece of functional unit sends control signal, controls to adjust this variable gain amplifier
Amplification or control adjust this common-mode voltage and compensate the compensation voltage of circuit and or control to adjust this electricity
The reference voltage of pressing mold number converter so that this voltage modulus that the voltage range of this fingerprint image drops into turns
Position appropriate in the range of changing the voltage measurement of circuit, so, protective layer in uneven thickness with
And in the case of fingerprint differs greatly between user, still can obtain more clearly fingerprint image.
In conjunction with first aspect, in the first possible implementation of first aspect, described signal processing list
Unit controls to adjust the amplification of described variable gain amplifier, the reference voltage of described voltage-mode number converter
With described common-mode voltage compensate circuit compensation magnitude of voltage at least one, particularly as follows:
When the histogrammic voltage range of described initial fingerprint image exceeds the voltage of described voltage-mode number converter
During measurement scope, the reference voltage of described voltage-mode number converter is heightened, or reduces described adjustable gain
The amplification of amplifier；
When the histogrammic voltage range of described initial fingerprint image accounts for the voltage survey of described voltage-mode number converter
When the ratio of weight range is less than preset ratio, the reference voltage of described voltage-mode number converter is turned down, or
Increase the amplification of described variable gain amplifier.
In conjunction with first aspect, or the first possible implementation of first aspect, in the of first aspect
In two kinds of possible implementations, described common-mode voltage compensates circuit and includes D/A converting circuit.
In conjunction with first aspect, or the first possible implementation of first aspect, in the of first aspect
In three kinds of possible implementations, described variable gain amplifier is by the series connection of multistage adjustable gain amplifying circuit
Become.
In conjunction with the third possible implementation of first aspect, in the 4th kind of possible realization of first aspect
In mode, described variable gain amplifier is switched capacitor amplifier.
In conjunction with first aspect, or the first possible implementation of first aspect, in the of first aspect
In five kinds of possible implementations, described voltage-mode number converter is production line analog-digital converter or is gradually
Approach analog-digital converter.
In conjunction with the 5th kind of possible implementation of first aspect, in the 6th kind of possible realization of first aspect
In mode, the resolution of described voltage-mode number converter is least significant bit LSB voltage.
In conjunction with first aspect, or the first possible implementation of first aspect, in the of first aspect
In seven kinds of possible implementations, described signal processing unit controls to adjust putting of described variable gain amplifier
Big multiple, the reference voltage of described voltage-mode number converter and described common-mode voltage compensate the voltage of circuit compensation
In value at least one, particularly as follows:
Calculate the voltage width of voltage range in described rectangular histogram；
Calculate the voltage width of the voltage measurement scope of described voltage-mode number converter；
Judge the magnitude relationship of the voltage width of described voltage range and the voltage width of described voltage measurement scope；
When the voltage width of described voltage range is more than the voltage width of described voltage measurement scope, by described
The reference voltage of voltage-mode number converter is heightened, or reduces the amplification of described variable gain amplifier,
So that the voltage width of described voltage range is equal with the voltage width of described voltage measurement scope；
When the voltage width of described voltage range is less than the voltage width of described voltage measurement scope, by described
The reference voltage of voltage-mode number converter is turned down, or increases the amplification of described variable gain amplifier,
So that the voltage width of described voltage range is equal with the voltage width of described voltage measurement scope.
In conjunction with the 7th kind of possible implementation of first aspect, in the 8th kind of possible realization of first aspect
In mode, when the voltage width of described voltage range is equal with the voltage width of described voltage measurement scope,
Described signal processing unit is additionally operable to:
Obtain the voltage range maximum in described rectangular histogram and voltage minimum；
The intermediate value of described voltage range is calculated according to described voltage max and described voltage minimum；
Calculate the centre of the intermediate value of described voltage range and the voltage measurement scope of described voltage-mode number converter
The voltage difference of value；
Compensation voltage is determined according to described voltage difference；
Compensate circuit to described common-mode voltage and send control signal to control the compensation circuit output of described common-mode voltage
Voltage with described compensation voltage formed objects.
In conjunction with the 8th kind of possible implementation of first aspect, in the 9th kind of possible realization of first aspect
In mode, described fingerprint induction arrays, described variable gain amplifier, described common-mode voltage compensation circuit,
Described voltage-mode number converter and described signal processing unit are integrated in same application-specific integrated circuit ASIC.
By implementing the embodiment of the present invention, this fingerprint acquisition device can be by signal processing unit to collecting
The rectangular histogram of fingerprint image be analyzed, it is judged that this electricity whether voltage range of this fingerprint image drops into
Position appropriate in the range of the voltage measurement of pressure analog to digital conversion circuit, if not falling under appropriate position
Then compensate circuit and voltage modulus by this signal processing unit to this variable gain amplifier, this common-mode voltage
In transducer, at least one piece of functional unit sends control signal, controls to adjust the amplification of this variable gain amplifier
Multiple or control adjust this common-mode voltage and compensate the compensation voltage of circuit and or control to adjust this voltage-mode
The reference voltage of number converter so that this voltage-mode number conversion electricity that the voltage range of this fingerprint image drops into
Position appropriate in the range of the voltage measurement on road, so, in the in uneven thickness of protective layer and use
More clearly fingerprint image still can be obtained in the case of fingerprint differs greatly between family.
Accompanying drawing explanation
In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to enforcement
In example or description of the prior art, the required accompanying drawing used is briefly described, it should be apparent that, describe below
In accompanying drawing be some embodiments of the present invention, for those of ordinary skill in the art, do not paying wound
On the premise of the property made work, it is also possible to obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the structural representation of a kind of fingerprint acquisition device of the prior art；
Fig. 2 is the principle schematic that a kind of fingerprint acquisition device of the prior art gathers fingerprint；
Fig. 3 is the structural representation of a kind of fingerprint acquisition device that the embodiment of the present invention provides；
Fig. 4 is a kind of rectangular histogram of the fingerprint image that the embodiment of the present invention provides；
Fig. 5 is another rectangular histogram of the fingerprint image that the embodiment of the present invention provides；
Fig. 6 is another rectangular histogram of the fingerprint image that the embodiment of the present invention provides.
Detailed description of the invention
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clearly
Chu, it is fully described by, it is clear that described embodiment is a part of embodiment of the present invention rather than complete
The embodiment in portion.Based on the embodiment in the present invention, those of ordinary skill in the art are not making creativeness
The every other embodiment obtained under work premise, broadly falls into the scope of protection of the invention.
It should be noted that the term used in embodiments of the present invention is in order at the mesh describing specific embodiment
, and it is not intended to be limiting the present invention.Odd number used in the embodiment of the present invention and appended claims
" a kind of ", " described " and " being somebody's turn to do " of form is also intended to include most form, unless context understands earth's surface
Show other implications.It is also understood that term "and/or" used herein refers to and comprises one or more
Any or all of the project of listing being associated may combination.It addition, the description and claims of the present invention
Term " first " in book and above-mentioned accompanying drawing, " second ", " the 3rd " and " the 4th " etc. are for difference not
With object rather than be used for describing particular order.Additionally, term " includes " and " having " and they
Any deformation, it is intended that cover non-exclusive comprising.Such as contain series of steps or the process of unit,
Method, system, product or equipment are not limited to step or the unit listed, but the most also include
The step do not listed or unit, or the most also include for these processes, method, product or equipment solid
Other step having or unit.
Referring to Fig. 3, Fig. 3 is a kind of fingerprint acquisition device 30 structural representation that the embodiment of the present invention provides,
This fingerprint acquisition device 30 includes that fingerprint induction arrays 301, variable gain amplifier 302, common-mode voltage are mended
Repay circuit 303, voltage-mode number converter 304 and signal processing unit 305, wherein, this fingerprint induction arrays
The output of 301 is connected with the input of this variable gain amplifier 302, the output of this variable gain amplifier 302
The signal of signal and this common-mode voltage output of compensating circuit 303 converge after, with this voltage-mode number converter
The input of 304 is connected, the output of this voltage-mode number converter 304 and the input phase of this signal processing unit 305
Even, this signal processing unit 305 can also arrange and compensate electricity with this variable gain amplifier 302, common-mode voltage
Three paths that road 303 is individually connected with voltage-mode number converter 304, for this variable gain amplifier
302, common-mode voltage compensates circuit 303 and voltage-mode number converter 304 is controlled.Further, also may be used
So that this fingerprint induction arrays 301, variable gain amplifier 302, common-mode voltage are compensated circuit 303, voltage
Analog-digital converter 304 and signal processing unit 305 are integrated in same special IC (Application
Specific Integrated Circuits, ASIC) in, the most constantly can save material cost and can also contract as far as possible
The time of short fingerprint collecting.
This fingerprint induction arrays 301, for gathering the finger print information of user's input, obtains voltage signal should
Voltage signal exports to this variable gain amplifier 302.This fingerprint induction arrays 301 can be based on quasiconductor
The semiconductor fingerprint sensor of silicon capacity effect technology, this semiconductor fingerprint sensor includes quasiconductor pressure-sensitive
Sensor, conductor temperature inductive transducer, semicoductor capacitor formula fingerprint sensor etc., the embodiment of the present invention
Emphasis launches to describe around the situation that this semiconductor fingerprint sensor is semicoductor capacitor formula fingerprint sensor.
Variable gain amplifier 302 is used for inputting the voltage signal of this fingerprint induction arrays 301 output, due to
The electric capacity formed between induction point in finger lines and fingerprint induction arrays 301 is the least, therefore the little electricity formed
Pressure-volume is vulnerable to the influence of noise of circuit, so needing by 302 voltages obtained of variable gain amplifier
Signal amplification is amplified signal, and after being amplified signal, this variable gain amplifier 302 exports this amplification letter
Number.This variable gain amplifier 302 can include an amplifier element, it is also possible to includes multiple amplifier element,
This amplifier element can be PNP type triode, NPN type triode etc., when there is multiple amplifier element,
The plurality of amplifier element can be connected.It should be noted that the amplification of this variable gain amplifier 302
Can be adjusted the most in good time, such as, this variable gain amplifier 302 is set to switching capacity
Amplifier, the most just can control the opening and closing of capacitance switch to control amplification.
This common-mode voltage compensates circuit 303 for output voltage signal with defeated with this variable gain amplifier 302
The amplification Signal averaging gone out is together, in order to eliminate the noise in this amplification signal, fingerprint induction arrays 301
Technological problems certain noise, each relevant circuit can be caused the most all to produce certain noise, these
Noise can affect the effect of follow-up fingerprint image, it is therefore desirable to compensates noise, i.e. eliminates noise.
This common-mode voltage compensates circuit 303 and is additionally operable to export the amplification signal eliminating noise turn to this voltage modulus
Parallel operation 304.It should be noted that this common-mode voltage compensates circuit 303 can be specially a digital-to-analogue conversion electricity
Road, the input of common-mode voltage compensation circuit 303 have input digital voltage signal and can mend from this common-mode voltage
Repay the outfan output analog voltage signal of circuit 303.
This voltage-mode number converter 304 is for inputting this amplification signal eliminating noise, by this letter of input
Number be converted to digital signal, then this digital signal exported to this signal processing unit 305.This voltage modulus
Transducer 304 can be production line analog-digital converter, it is also possible to for gradually-appoximant analog-digital converter, certainly go back
Can be other analog-digital converters.Resolution Q of this voltage-mode number converter 304 can be least significant bit
(Least significant bit, LSB) voltage, in other words, the resolution of this voltage-mode number converter 304
Q is equal to the voltage measurement scope of this voltage-mode number converter 304 divided by discrete voltage space-number, and this voltage is surveyed
Weight range is also full range voltage scope, and it is equal to the reference voltage of this voltage-mode number converter 304, and electric
The pressure space-number M power equal to 2, M is the figure place of this voltage-mode number converter 304, so adjusting this electricity
The reference voltage of pressing mold number converter 304 can regulate total voltage measurement of this voltage-mode number converter 304
Scope and the resolution of output signal.For example, if the voltage-mode number converter 304 of 8
Can measure in the range of 0v～10v, correspondingly resolution Q of output signal be equal to 10/2^8, i.e. 10/256.
Further, the reference voltage of this voltage-mode number converter 304 can adjust the most in good time.
This signal processing unit 305 is for obtaining initial fingerprint image according to this digital signal, it is judged that this is initial
It is pre-conditioned whether the rectangular histogram of fingerprint image meets.
Specifically, this signal processing unit 305 inputs the digital signal of this voltage-mode number converter 304 output,
This digital signal being carried out process and obtains fingerprint image, the fingerprint image starting to obtain is initial fingerprint image,
This signal processing unit 305 can obtain the rectangular histogram of this initial fingerprint image, then judges this initial fingerprint
It is pre-conditioned whether the rectangular histogram of image meets, such as, it is judged that (this histogrammic transverse axis embodies this rectangular histogram
The voltage range of fingerprint image) in the voltage range of this initial fingerprint image whether beyond this voltage modulus
The voltage measurement scope of transducer 304, if exceeding, shows that the rectangular histogram of this initial fingerprint image is unsatisfactory for pre-
If condition, Fig. 4 is the voltage range electricity beyond this voltage-mode number converter 304 of this initial fingerprint image
The schematic diagram of pressure measurement scope.For another example, it is judged that the voltage range of this initial fingerprint image accounts for this voltage modulus and turns
Whether the ratio of the voltage measurement scope of parallel operation 304 (can be arranged according to actual needs less than preset ratio
The size of this ratio, such as, be set to 60%), if less than, show that the rectangular histogram of this initial fingerprint image is discontented with
Foot is the most pre-conditioned, and Fig. 5 is the voltage measurement that the voltage range of fingerprint image accounts for this voltage-mode number converter 304
The ratio of scope is less than the schematic diagram of preset ratio.For another example, it is judged that the voltage range of this initial fingerprint image exists
In the range of the voltage measurement of this voltage-mode number converter 304 the most between two parties, if deviation centre position is farther out, table
The rectangular histogram of this initial fingerprint image bright is unsatisfactory for pre-conditioned (such as, the voltage model of this initial fingerprint image
The intermediate value enclosed is pre-at one with the difference of the intermediate value of the voltage measurement scope of this voltage-mode number converter 304
Show to meet pre-conditioned in the range of if), Fig. 6 is that the voltage range of this initial fingerprint image is in this voltage-mode
By the schematic diagram of middle position in the voltage measurement scope of number converter 304.Other can also be set certainly
Rule of judgment, other Rule of judgment differs a citing herein.
This signal processing unit 305 is additionally operable to be unsatisfactory for presetting in the rectangular histogram judging this initial fingerprint image
During condition, control to adjust the amplification of this variable gain amplifier 302, this voltage-mode number converter 304
Reference voltage and this common-mode voltage compensate at least one in the magnitude of voltage that circuit 303 compensates, until this signal
It is pre-conditioned that the rectangular histogram of the fingerprint image that processing unit 305 obtains according to this digital signal meets this.
Specifically, if the rectangular histogram of this initial fingerprint image is unsatisfactory for pre-conditioned, then this signal processing unit
305 control to adjust the amplification of adjustable gain amplifying circuit, or control to adjust this voltage-mode number converter
The reference voltage of 304, or adjust the magnitude of voltage that this common-mode voltage compensation circuit 303 compensates；Until this signal
The rectangular histogram of the fingerprint image that processing unit 305 is newly-generated disclosure satisfy that pre-conditioned.
For example, when the maximum in the voltage range fingerprint image shown in Fig. 4 occur is more than this voltage
Maximum in the voltage measurement scope of analog-digital converter 304, and in the voltage range of this fingerprint image
Little value (tends to occur at finger when being less than the minima in the voltage measurement scope of this voltage-mode number converter 304
In the case of the saturation of stricture of vagina is too high), this signal processing unit 305 can based on this voltage-mode number converter
The path set up between 304, sends control signal to heighten this voltage modulus to this voltage-mode number converter 304
The reference voltage of transducer 304；Or this signal processing unit 305 can amplify based on this adjustable gain
The path set up between device 302, sends control signal to this variable gain amplifier 302 adjustable to reduce this
The amplification of gain amplifier 302 so that the voltage range of this initial fingerprint image eventually falls into this voltage
The voltage measurement scope of analog-digital converter 304.
When the voltage range fingerprint image shown in Fig. 5 occur falls into the voltage of this voltage-mode number converter 304
Measurement scope, and the voltage range of this fingerprint image is in the voltage measurement scope of this voltage-mode number converter 304
In the ratio that accounts for less time (tend to occur at the saturation of fingerprint too low in the case of), this signal processing unit
305 can be based on the path set up between this voltage-mode number converter 304, to this voltage-mode number converter
304 send control signal turns down the reference voltage of this voltage-mode number converter 304；Or this signal processing list
Unit 305 can amplify to this adjustable gain based on the path set up between this variable gain amplifier 302
Device 302 sends control signal to increase the amplification of this variable gain amplifier 302 so that this initially refers to
The ratio of the voltage measurement scope that the voltage range of print image accounts for this voltage-mode number converter 304 rises to preset
Value.
When the maximum of the voltage range fingerprint image shown in Fig. 6 occur is more than this voltage-mode number converter 304
The maximum of voltage measurement scope, but the minima of the voltage range of this fingerprint image is more than this voltage modulus
During the minima of the voltage measurement scope of transducer 304, (minima of the voltage range of fingerprint image was less than should
The minima of the voltage measurement scope of voltage-mode number converter 304, but the voltage range of this fingerprint image is
Big value less than during the maximum of the voltage measurement scope of this voltage-mode number converter 304 in like manner), this signal processing
Unit 305 can compensate, based on this common-mode voltage, the path set up between circuit 303, to this common-mode voltage
Compensate circuit 303 and send control signal to adjust the compensation voltage of this common-mode voltage compensation circuit 303 output
Size so that the intermediate value of the voltage range of this initial fingerprint image is near this voltage-mode number converter 304
The intermediate value of voltage measurement scope.Further, lean on when the intermediate value of the voltage range of this initial fingerprint image
During the intermediate value of the voltage measurement scope of this voltage-mode number converter 304 nearly, if occurring in that again Fig. 4 and Fig. 5
Shown situation, then this signal processing unit 305 can control the times magnification of this variable gain amplifier 302
Count, or the reference voltage of this voltage-mode number converter 304 solves produced problem.
Optionally, in the event of voltage width and the voltage-mode number converter 304 of the voltage range in rectangular histogram
The voltage width of voltage measurement scope different, and the intermediate value of this voltage range and this voltage measurement scope
When intermediate value differs farther out, can be processed by following flow process:
The first step: described signal processing unit 305 calculates the voltage width of the voltage range in described rectangular histogram.
Second step: described signal processing unit 305 calculates the voltage measurement of described voltage-mode number converter 304
The voltage width of scope.
3rd step: described signal processing unit 305 judges the voltage width of described voltage range and described voltage
The magnitude relationship of the voltage width of measurement scope.
4th step: when the voltage width of described voltage range is more than the voltage width of described voltage measurement scope,
The reference voltage of described voltage-mode number converter 304 is heightened by described signal processing unit 305, or reduces
The amplification of described variable gain amplifier 302, so that the voltage width of described voltage range and described electricity
The voltage width of pressure measurement scope is equal；
When the voltage width of described voltage range is less than the voltage width of described voltage measurement scope, described letter
The reference voltage of described voltage-mode number converter 304 is turned down by number processing unit 305, or increase described can
Adjust the amplification of gain amplifier 302, so that the voltage width of described voltage range and described voltage measurement
The voltage width of scope is equal.
5th step: when the voltage width of described voltage range is equal with the voltage width of described voltage measurement scope
Time, described signal processing unit 305 obtains the voltage range maximum in described rectangular histogram and voltage minimum.
6th step: described signal processing unit 305 is according to described voltage max and described voltage minimum meter
Calculate the intermediate value of described voltage range.
7th step: described signal processing unit 305 calculates the intermediate value of described voltage range and described voltage-mode
The voltage difference of the intermediate value of the voltage measurement scope of number converter 304.
8th step: described signal processing unit 305 determines compensation voltage according to described voltage difference.
9th step: described signal processing unit 305 compensates circuit 303 to described common-mode voltage and sends control letter
Number compensate circuit 303 output and the voltage of described compensation voltage formed objects controlling described common-mode voltage.
It should be noted that the above-mentioned first step is only a kind of optional scheme, in reality to the scheme of the 9th step
By adjusting the order of these steps in the operating process of border, or omit some steps, or be similar to other
Step replaces some step therein can also reach same or like beneficial effect.The embodiment of the present invention
Described in " voltage width " be generally directed to a voltage range for, if the span of voltage is
0v～10v, then corresponding voltage width is (10-0)=10v；If the span of voltage is 20v～100v,
So corresponding voltage width is (100-20)=80v.
Optionally, the intermediate value of the voltage range of fingerprint image can voltage range based on this fingerprint image
Big value and minima are calculated by preset algorithm, the voltage measurement scope of this voltage-mode number converter 304
Intermediate value can the maximum of voltage measurement scope based on this voltage-mode number converter 304 and minima lead to
Cross preset algorithm to be calculated.The size compensating voltage can also be in voltage range based on this fingerprint image
Between the mathematic interpolation of intermediate value of voltage measurement scope of value and this voltage-mode number converter 304 obtain.
Optionally, this signal processing unit 305 can according to the maximum of the voltage range of this fingerprint image and
Minima calculates the maximum gray scale difference of fingerprint image, and this gray scale difference needs to be distributed in voltage-mode number conversion as far as possible
In the range of the voltage measurement of device 304, the balance of contrast and saturation to reach whole fingerprint image, enter
One step ground, this signal processing unit 305 can be combined with this gray scale difference and this voltage-mode number converter 304
Voltage measurement scope determines the amplification of this variable gain amplifier 302.Further, at this signal
Reason unit 305 is also based on maximum and the difference of minima of the voltage range of this fingerprint image, for this
The reference voltage of voltage-mode number converter 304.
In the fingerprint acquisition device 30 shown in Fig. 3, this fingerprint acquisition device 30 can pass through signal processing
The rectangular histogram of the unit 305 fingerprint image to collecting is analyzed, it is judged that the voltage range of this fingerprint image
Position appropriate in the range of the voltage measurement of this voltage-mode number converter 304 whether dropped into, if not having
Drop into appropriate position then by this signal processing unit 305 to this variable gain amplifier 302, this altogether
Mode voltage compensates at least one piece of functional unit in circuit 303 and voltage-mode number converter 304 and sends control signal,
Control to adjust the amplification of this variable gain amplifier or control to adjust this common-mode voltage to compensate circuit 303
Compensate voltage and or control adjust this voltage-mode number converter 304 reference voltage so that this fingerprint image
Position appropriate in the range of the voltage measurement of this voltage analog to digital conversion circuit 303 that the voltage range of picture drops into
Putting, so, between the in uneven thickness of protective layer and user, fingerprint still may be used in the case of differing greatly
Obtain more clearly fingerprint image.
One of ordinary skill in the art will appreciate that all or part of flow process realizing in above-described embodiment method,
Can be by computer program and complete to instruct relevant hardware, described program can be stored in computer
In read/write memory medium, this program is upon execution, it may include such as the flow process of the embodiment of above-mentioned each method.
And aforesaid storage medium includes: ROM, RAM, magnetic disc or CD etc. are various can store program code
Medium.
Above example only discloses preferred embodiment in the present invention, it is impossible to limit the right of the present invention with this
Scope, one of ordinary skill in the art will appreciate that all or part of flow process realizing above-described embodiment, and depends on
The equivalent variations that the claims in the present invention are made, still falls within the scope that invention is contained.
Claims (10)
1. a fingerprint acquisition device, it is characterised in that described fingerprint acquisition device include fingerprint induction arrays,
Variable gain amplifier, common-mode voltage compensate circuit, voltage-mode number converter and signal processing unit, wherein:
Described fingerprint induction arrays, is used for gathering finger print information to obtain voltage signal, and is believed by described voltage
Number output to described variable gain amplifier；
Described variable gain amplifier, for amplifying described voltage signal to be amplified signal；
Described common-mode voltage compensates circuit, for believing described amplification signal compensation voltage to eliminate described amplification
Common-mode voltage in number and noise；
Described voltage-mode number converter, for receiving the amplification letter eliminating described common-mode voltage and described noise
Number, and the amplification signal eliminating described common-mode voltage and described noise is converted to digital signal；By described
Digital signal exports to described signal processing unit；
Described signal processing unit, for obtaining initial fingerprint image according to described digital signal, it is judged that described
It is pre-conditioned whether the rectangular histogram of initial fingerprint image meets；If being unsatisfactory for, then control to adjust described adjustable increasing
The amplification of benefit amplifier, the reference voltage of described voltage-mode number converter and described common-mode voltage compensate electricity
In the magnitude of voltage that road compensates at least one, until what described signal processing unit obtained according to described digital signal
The rectangular histogram of fingerprint image meets described pre-conditioned.
Fingerprint acquisition device the most according to claim 1, it is characterised in that described signal processing unit
Control adjust described variable gain amplifier amplification, the reference voltage of described voltage-mode number converter and
Described common-mode voltage compensate circuit compensation magnitude of voltage at least one, particularly as follows:
When the histogrammic voltage range of described initial fingerprint image exceeds the voltage of described voltage-mode number converter
During measurement scope, the reference voltage of described voltage-mode number converter is heightened, or reduces described adjustable gain
The amplification of amplifier；
When the histogrammic voltage range of described initial fingerprint image accounts for the voltage survey of described voltage-mode number converter
When the ratio of weight range is less than preset ratio, the reference voltage of described voltage-mode number converter is turned down, or
Increase the amplification of described variable gain amplifier.
Fingerprint acquisition device the most according to claim 1 and 2, it is characterised in that described common-mode voltage
Compensate circuit and include D/A converting circuit.
Fingerprint acquisition device the most according to claim 1 and 2, it is characterised in that described adjustable gain
Amplifier is in series by multistage adjustable gain amplifying circuit.
Fingerprint acquisition device the most according to claim 4, it is characterised in that described adjustable gain amplifies
Device is switched capacitor amplifier.
Fingerprint acquisition device the most according to claim 1 and 2, it is characterised in that described voltage modulus
Transducer is production line analog-digital converter or is gradually-appoximant analog-digital converter.
Fingerprint acquisition device the most according to claim 6, it is characterised in that described voltage-mode number conversion
The resolution of device is least significant bit LSB voltage.
Fingerprint acquisition device the most according to claim 1 and 2, its feature is being, at described signal
Reason unit controls to adjust the amplification of described variable gain amplifier, the reference of described voltage-mode number converter
Voltage and described common-mode voltage compensate at least one in the magnitude of voltage of circuit compensation, particularly as follows:
Calculate the voltage width of voltage range in described rectangular histogram；
Calculate the voltage width of the voltage measurement scope of described voltage-mode number converter；
Judge the magnitude relationship of the voltage width of described voltage range and the voltage width of described voltage measurement scope；
When the voltage width of described voltage range is more than the voltage width of described voltage measurement scope, by described
The reference voltage of voltage-mode number converter is heightened, or reduces the amplification of described variable gain amplifier,
So that the voltage width of described voltage range is equal with the voltage width of described voltage measurement scope；
When the voltage width of described voltage range is less than the voltage width of described voltage measurement scope, by described
The reference voltage of voltage-mode number converter is turned down, or increases the amplification of described variable gain amplifier,
So that the voltage width of described voltage range is equal with the voltage width of described voltage measurement scope.
Fingerprint acquisition device the most according to claim 8, it is characterised in that when described voltage range
When voltage width is equal with the voltage width of described voltage measurement scope, described signal processing unit is additionally operable to:
Obtain the voltage range maximum in described rectangular histogram and voltage minimum；
The intermediate value of described voltage range is calculated according to described voltage max and described voltage minimum；
Calculate the centre of the intermediate value of described voltage range and the voltage measurement scope of described voltage-mode number converter
The voltage difference of value；
Compensation voltage is determined according to described voltage difference；
Compensate circuit to described common-mode voltage and send control signal to control the compensation circuit output of described common-mode voltage
Voltage with described compensation voltage formed objects.
Fingerprint acquisition device the most according to claim 9, it is characterised in that described fingerprint sensing battle array
Row, described variable gain amplifier, described common-mode voltage compensate circuit, described voltage-mode number converter and institute
State signal processing unit to be integrated in same application-specific integrated circuit ASIC.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610200121 | 2016-03-31 | ||
| CN201610200121X | 2016-03-31 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105913049A true CN105913049A (en) | 2016-08-31 |
| CN105913049B CN105913049B (en) | 2020-04-10 |
Family
ID=56748666
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610345417.0A Active CN105913049B (en) | 2016-03-31 | 2016-05-23 | Fingerprint acquisition device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105913049B (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107798287A (en) * | 2017-08-29 | 2018-03-13 | 北京集创北方科技股份有限公司 | A kind of biological feather recognition method and device |
| CN108460371A (en) * | 2018-04-16 | 2018-08-28 | 北京中天维科技有限公司 | A kind of fingerprint sensor acquisition system and method |
| CN108596060A (en) * | 2018-04-12 | 2018-09-28 | 上海思立微电子科技有限公司 | Fingerprint image processing method, fingerprint identification device and electronic equipment |
| CN111027516A (en) * | 2019-12-25 | 2020-04-17 | 北京集创北方科技股份有限公司 | Biological characteristic image acquisition device and method and intelligent equipment |
| CN112233410A (en) * | 2020-10-14 | 2021-01-15 | 深圳市康冠商用科技有限公司 | Automatic gain level selection method and device, computer equipment and storage medium |
| CN112637510A (en) * | 2021-03-05 | 2021-04-09 | 南京智谱科技有限公司 | Scene self-adaptive image gain adjusting method, system and device and electronic equipment |
| US11501554B2 (en) * | 2020-09-10 | 2022-11-15 | Fingerprint Cards Anacatum Ip Ab | Fingerprint sensor with different measurement circuitry configurations |
| TWI831017B (en) * | 2021-06-09 | 2024-02-01 | 大陸商北京集創北方科技股份有限公司 | Capacitive fingerprint collection module, fingerprint identification device and information processing device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1290383A (en) * | 1997-05-16 | 2001-04-04 | 奥森泰克公司 | Fingerprint sensor with gain control features and associated methods |
| CN102279924A (en) * | 2010-06-11 | 2011-12-14 | 金鹏科技有限公司 | Fingerprint identification system and testing device |
| US20150023571A1 (en) * | 2013-07-22 | 2015-01-22 | Apple Inc. | Controllable Signal Processing in a Biometric Device |
| US20150071507A1 (en) * | 2013-09-09 | 2015-03-12 | Apple Inc. | Reconstructing a Biometric Image |
-
2016
- 2016-05-23 CN CN201610345417.0A patent/CN105913049B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1290383A (en) * | 1997-05-16 | 2001-04-04 | 奥森泰克公司 | Fingerprint sensor with gain control features and associated methods |
| CN102279924A (en) * | 2010-06-11 | 2011-12-14 | 金鹏科技有限公司 | Fingerprint identification system and testing device |
| US20150023571A1 (en) * | 2013-07-22 | 2015-01-22 | Apple Inc. | Controllable Signal Processing in a Biometric Device |
| US20150071507A1 (en) * | 2013-09-09 | 2015-03-12 | Apple Inc. | Reconstructing a Biometric Image |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107798287A (en) * | 2017-08-29 | 2018-03-13 | 北京集创北方科技股份有限公司 | A kind of biological feather recognition method and device |
| CN107798287B (en) * | 2017-08-29 | 2020-07-17 | 北京集创北方科技股份有限公司 | Biological feature recognition method and device |
| CN108596060A (en) * | 2018-04-12 | 2018-09-28 | 上海思立微电子科技有限公司 | Fingerprint image processing method, fingerprint identification device and electronic equipment |
| CN108596060B (en) * | 2018-04-12 | 2021-10-15 | 上海思立微电子科技有限公司 | Fingerprint image processing method, fingerprint identification device and electronic equipment |
| CN108460371A (en) * | 2018-04-16 | 2018-08-28 | 北京中天维科技有限公司 | A kind of fingerprint sensor acquisition system and method |
| CN111027516A (en) * | 2019-12-25 | 2020-04-17 | 北京集创北方科技股份有限公司 | Biological characteristic image acquisition device and method and intelligent equipment |
| CN111027516B (en) * | 2019-12-25 | 2024-01-26 | 北京集创北方科技股份有限公司 | Biological characteristic image acquisition device, biological characteristic image acquisition method and intelligent equipment |
| US11501554B2 (en) * | 2020-09-10 | 2022-11-15 | Fingerprint Cards Anacatum Ip Ab | Fingerprint sensor with different measurement circuitry configurations |
| CN112233410A (en) * | 2020-10-14 | 2021-01-15 | 深圳市康冠商用科技有限公司 | Automatic gain level selection method and device, computer equipment and storage medium |
| CN112637510A (en) * | 2021-03-05 | 2021-04-09 | 南京智谱科技有限公司 | Scene self-adaptive image gain adjusting method, system and device and electronic equipment |
| TWI831017B (en) * | 2021-06-09 | 2024-02-01 | 大陸商北京集創北方科技股份有限公司 | Capacitive fingerprint collection module, fingerprint identification device and information processing device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN105913049B (en) | 2020-04-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105913049A (en) | Fingerprint collection device | |
| CN106022271A (en) | Fingerprint collection method | |
| JP4036798B2 (en) | Capacitance detection circuit, detection method, and fingerprint sensor | |
| US8830207B1 (en) | Method and apparatus for improving dynamic range of a touchscreen controller | |
| US10642431B2 (en) | Capacitance detection circuit, capacitance detection method, touch detection apparatus, and terminal device | |
| CN106537106B (en) | Capacitance detecting device, method and pressure detecting system | |
| CN101939708B (en) | Minimal dead time digitally compensated process transmitter | |
| US8514191B2 (en) | Touch panel sensing circuit | |
| CN105574520B (en) | Signal processing circuit and method for fingerprint sensor | |
| CN106156763B (en) | Fingerprint identification module and fingerprint identification method | |
| US5987156A (en) | Apparatus for correcting fixed column noise in images acquired by a fingerprint sensor | |
| CN105528574A (en) | Fingerprint detecting apparatus canceling offset and control method thereof | |
| KR102237710B1 (en) | Capacitor type Humidity Sensor | |
| US9710690B1 (en) | Fingerprint sensing system with adaptive power control | |
| CN105913048A (en) | Fingerprint processing device | |
| CN107026991B (en) | Image sensing apparatus | |
| CN111122020B (en) | Capacitive pressure detection device and sensor | |
| CN205507799U (en) | A processing circuit for fingerprint sensor | |
| KR20160144466A (en) | Active baseline signal cancellation in fingerprint sensors | |
| JP2018515946A (en) | Fingerprint detection circuit and electronic device | |
| CN105975947B (en) | Global scanning type fingerprint processing method | |
| CN110895293A (en) | Differential mutual capacitance detection circuit, method, chip and equipment | |
| US8421666B2 (en) | Analog to digital converter with adjustable conversion window | |
| CN206209771U (en) | A kind of fingerprint collecting framework | |
| CN112000249A (en) | Capacitance detection circuit, touch control chip and parameter adjustment method of capacitance detection circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 518000 East of Building A, 22, Shenzhen International Innovation Center, 1006 Shennan Avenue, Huafu Street, Futian District, Shenzhen City, Guangdong Province Patentee after: Shenzhen Biocome Security Technology Co.,Ltd. Address before: 518000 East of Building A, 22, Shenzhen International Innovation Center, 1006 Shennan Avenue, Huafu Street, Futian District, Shenzhen City, Guangdong Province Patentee before: SHENZHEN BIOCOME SECURITY TECHNOLOGY CO.,LTD. |
|
| CP01 | Change in the name or title of a patent holder |