WO2017067109A1 - 输出转换电路及指纹识别系统 - Google Patents

输出转换电路及指纹识别系统 Download PDF

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WO2017067109A1
WO2017067109A1 PCT/CN2016/071681 CN2016071681W WO2017067109A1 WO 2017067109 A1 WO2017067109 A1 WO 2017067109A1 CN 2016071681 W CN2016071681 W CN 2016071681W WO 2017067109 A1 WO2017067109 A1 WO 2017067109A1
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output signal
output
signal
reference signal
random number
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PCT/CN2016/071681
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English (en)
French (fr)
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谭波
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深圳市汇顶科技股份有限公司
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Priority to EP16856557.0A priority Critical patent/EP3206159B1/en
Priority to KR1020177012243A priority patent/KR101882895B1/ko
Priority to US15/490,885 priority patent/US10204258B2/en
Publication of WO2017067109A1 publication Critical patent/WO2017067109A1/zh

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    • 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
    • G06V40/1318—Sensors therefor using electro-optical elements or layers, e.g. electroluminescent sensing
    • 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
    • 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
    • G06V40/1347—Preprocessing; Feature extraction
    • 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
    • G06V40/1365—Matching; Classification
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/96—Touch switches
    • H03K17/962—Capacitive touch switches
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/06—Continuously compensating for, or preventing, undesired influence of physical parameters
    • H03M1/0617—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence
    • H03M1/0634—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence by averaging out the errors, e.g. using sliding scale
    • H03M1/0656—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence by averaging out the errors, e.g. using sliding scale in the time domain, e.g. using intended jitter as a dither signal
    • H03M1/066—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence by averaging out the errors, e.g. using sliding scale in the time domain, e.g. using intended jitter as a dither signal by continuously permuting the elements used, i.e. dynamic element matching
    • H03M1/0665—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence by averaging out the errors, e.g. using sliding scale in the time domain, e.g. using intended jitter as a dither signal by continuously permuting the elements used, i.e. dynamic element matching using data dependent selection of the elements, e.g. data weighted averaging
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/66—Digital/analogue converters

Definitions

  • the invention relates to an output conversion circuit and a fingerprint identification system, in particular to an output conversion circuit and a fingerprint identification system which can improve the statistical linearity of an output signal.
  • the fingerprint recognition system uses a pixel array circuit to receive a finger contact, and the pixel array circuit converts the capacitance between the pixel array circuit and the finger into a pixel output signal, and the pixel output signal is affected by noise without having a good Statistical linearity is not conducive to image processing at the back end. Therefore, how to improve the statistical linearity of the output signal of the fingerprint recognition system has become one of the goals of the industry.
  • the present invention provides an output conversion circuit including: a comparator, a counter, and a reference signal generator; the counter includes: a first input terminal for receiving the first output signal; a second input terminal; and an output terminal for generating a comparison output signal; a counter connected to the output end of the comparator for generating the second output signal; a reference signal generator connected to the second input terminal Generating a reference signal, the reference signal generator includes a random number generator, the random number generator is configured to generate a random number, the reference signal is related to the random number; and the comparator is configured according to the first output signal and the reference signal , the comparison output signal is generated.
  • the reference signal is a signal that varies randomly with time, and the random number is uniformly distributed.
  • the reference signal generator comprises a control circuit that outputs a reference voltage having a fixed voltage value.
  • the reference signal is related to the sum of the reference voltage and the random number.
  • the reference signal generator further comprises a digital to analog converter for converting the reference voltage and the sum of the random numbers into the analog reference signal.
  • the comparison output signal when the first output signal is greater than the reference signal, the comparison output signal is a first potential, and when the first output signal is less than the reference signal, the comparison output signal is a second potential.
  • a fingerprint recognition system comprising a pixel array circuit, the first input being coupled to the pixel array circuit.
  • the pixel array circuit comprises at least one pixel circuit.
  • the pixel array circuit is adapted to accept the contact of the finger and convert the capacitance formed between the pixel array circuit and the finger into a pixel output signal, the pixel output signal being related to the first output signal.
  • the fingerprint identification system further includes an amplifier connected between the pixel array circuit and the first input terminal for enhancing the signal strength of the pixel output signal to become the first output signal.
  • the present invention also provides a fingerprint identification system, including:
  • a pixel array circuit for accepting contact of a finger and converting a capacitance formed between the pixel array circuit and the finger into a pixel output signal
  • An output conversion circuit for generating a second output signal according to the first output signal comprising:
  • Comparator including:
  • a counter coupled to the output of the comparator for generating the second output signal
  • a reference signal generator coupled to the second input, for generating a reference signal
  • the reference signal generator comprising a random number generator, the random number generator for generating a random number, the reference signal being related to the random Number
  • the fingerprint determination module is connected to the signal conversion circuit, and is configured to determine, according to the second output signal, that the pixel output signal corresponds to a bee or a grain valley;
  • the first output signal is related to the pixel output signal, and the comparator generates the comparison output signal according to the first output signal and the reference signal.
  • the random number generator is used to change the signal value of the reference signal, so that the first output signal with poor statistical linearity is converted into the second output signal with good statistical linearity, and the second The output signal is sent to the back-end image processing module for image processing at the back end.
  • FIG. 1 is a schematic diagram of an output conversion circuit according to an embodiment of the present invention.
  • FIG. 2 is a schematic diagram of a fingerprint identification system according to an embodiment of the present invention.
  • Figure 3 is a schematic diagram of the probability density function of a noise.
  • Figure 4 is a schematic diagram of a plurality of Gaussian functions.
  • Figure 5 is a schematic diagram of a sum function.
  • Figure 6 is a schematic illustration of the probability density function of the first output signal.
  • FIG. 1 is a schematic diagram of an output conversion circuit 10 according to an embodiment of the present invention.
  • the output conversion circuit 10 is for converting the first output signal Vo1 into a second output signal Vo2, and the output conversion circuit 10 includes a comparator 100, a counter 102, and a reference voltage generator 104.
  • the comparator 100 includes a negative input terminal (labeled with a "-" sign), a positive input terminal (labeled with a "+” sign), and an output terminal, and the positive input terminal (ie, the first input terminal of the comparator) is used to receive the first An output signal Vo1, the negative input terminal (ie, the second input terminal of the comparator) is coupled to the reference voltage generator 104 for receiving a reference signal VR.
  • the comparator 100 generates a comparison output signal Vcp according to the first output signal Vo1 and the reference signal VR and outputs a comparison output signal Vcp through the output terminal, and the comparison output signal Vcp can be logic 0 or logic 1.
  • the comparison output signal Vcp when the first output signal Vo1 is greater than the reference signal VR, the comparison output signal Vcp is logic 1 (corresponding to the first potential); and when the first output signal Vo1 is less than the reference signal VR, the comparison output signal Vcp It is logic 0 (corresponding to the second potential).
  • the counter 102 is connected to the output of the comparator 100 for accumulating the comparison output signal Vcp to generate a second output signal Vo2, that is, the second output signal Vo2 is an accumulation result of the comparison output signal Vcp.
  • the reference voltage generator 104 includes a control circuit 120, a random number generator 124 and a digital-to-analog converter 122.
  • the control circuit 120 is used to generate a fixed voltage V F for the digital, and the random number generator 124 is used to generate a digital one.
  • the random number RD, the digital to analog converter 122 is used to convert a sum of the fixed voltage V F and the random number RD into an analog reference signal VR.
  • the random number RD presents a Uniform Distribution.
  • the operation of the output conversion circuit 10 is described below.
  • the noise noi is usually a non-uniform distribution
  • the statistical linearity of the first output signal Vo1 is not good, in other words, for a fixed interval ⁇ , the fixed interval ⁇
  • the probability of being near the specific value a is different from the probability that the fixed interval ⁇ is near another specific value b, for example, F(a + ⁇ ) - F(a) ⁇ F(b + ⁇ ) - F(b).
  • a plurality of translated probability density functions can be superimposed on each other, and the superposed one-sum function can have a uniform distribution characteristic. Specifically, please refer to FIG. 4 and FIG. 5.
  • FIG. 4 and FIG. 5 FIG.
  • FIG. 4 is a schematic diagram of a Gaussian function p -N - p N
  • FIG. 5 is a schematic diagram of a sum function p SUM
  • the Gaussian function p 0 represents a Gaussian function with a center of 0
  • the Gaussian function p -N ⁇ p -1 represents a plurality of Gaussian functions that shift the Gaussian function p 0 to the left
  • the Gaussian functions p 1 ⁇ p N represent A Gaussian function p 0 is translated to the right by a plurality of Gaussian functions.
  • the sum function SUM is a result of superimposing all the Gaussian functions p - N - p N on each other. As can be seen from Fig. 5, the sum function p SUM has a uniform distribution characteristic at the center.
  • FIG. 6 is a schematic diagram of a probability density function q(x) of the first output signal Vo1.
  • the probability density function q(x) is centered on the useful signal sig of the first output signal Vo1, and the probability that the output signal Vcp is logic 0 is equal to the probability that the first output signal Vo1 is smaller than the reference signal VR (the mesh grid in FIG.
  • the line region), the probability that the comparison output signal Vcp is logic 1, is the probability that the first output signal Vo1 is greater than the reference signal VR (the dotted distribution region in FIG. 6).
  • can’t change
  • changing the signal value of the reference signal VR is equivalent to shifting the probability density function q(x) or to the left or to the right.
  • increasing the signal value of the reference signal VR is equivalent to The probability density function of the first output signal Vo1 is shifted to the left, and decreasing the signal value of the reference signal VR is equivalent to shifting the probability density function of the first output signal Vo1 to the right, wherein the signal value of the reference signal VR is changed to be random.
  • the number generator 124 is executed.
  • the second output signal Vo2 is an accumulation result of the comparison output signal Vcp, a probability density function of the second output signal Vo2 can be regarded as a result of superimposing the probability density function q(x), and having The uniform distribution characteristic as shown in FIG. 5, therefore, the second output signal Vo2 can have good statistical linearity.
  • the output conversion circuit 10 of the present invention uses the random number generator 124 to change the signal value of the reference signal VR such that the first output signal Vo1 having poor statistical linearity is converted into the second output signal Vo2 having good statistical linearity. And transmitting the second output signal Vo2 to the back end image processing module, the second output signal Vo2 having good statistical linearity is helpful for image processing of the back end.
  • FIG. 2 is a schematic diagram of a fingerprint identification system 20 according to an embodiment of the present invention.
  • the fingerprint recognition system 20 applies an output conversion circuit 10 and includes a pixel array circuit 22, an amplifier 24, and a fingerprint determination module 26.
  • the pixel array circuit 22 is adapted to accept the contact of the finger and convert the contact capacitance C F between the pixel array circuit 22 and the finger into a pixel output signal Vo.
  • the amplifier 24 is connected to the pixel array circuit 22 for enhancing the signal strength of the pixel output signal Vo to become the first output signal Vo1.
  • the first output signal Vo1 is a signal obtained by boosting the output signal Vo through the amplifier 24.
  • the positive input terminal of the comparator 100 in the output conversion circuit 10 is connected to the amplifier 24, and the comparator 100 generates a comparison output signal Vcp based on the first output signal Vo1 and the reference signal VR.
  • the output conversion circuit 10 is configured to convert the first output signal Vo1 with poor statistical linearity into a second output signal Vo2 with good statistical linearity, the second output signal Vo2 is output to the fingerprint determination module 26, and the fingerprint determination module 26 is based on the second output.
  • the signal Vo2 determines that the pixel output signal Vo corresponds to a Finger Ridge or a Finger Valley.
  • amplifier 24 is only used to enhance pixel loss.
  • the signal strength of the signal Vo is not limited thereto.
  • the fingerprint recognition system can directly connect the positive input terminal of the comparator to the pixel array circuit, which is also within the scope of the present invention.
  • the random number generator can be implemented using a perturbator (Dither) without being limited thereto.
  • the present invention utilizes a random number generator to change the signal value of the reference signal such that the first output signal having poor statistical linearity is converted into a second output signal having good statistical linearity, and the second output signal is transmitted.
  • a random number generator to change the signal value of the reference signal such that the first output signal having poor statistical linearity is converted into a second output signal having good statistical linearity, and the second output signal is transmitted.
  • To the back-end image processing module to facilitate image processing at the back end.

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  • General Physics & Mathematics (AREA)
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Abstract

本发明提供了一种输出转换电路及指纹识别系统，该输出转换电路包括：比较器、计数器、及参考信号产生器，计数器包括：第一输入端，用来接收该第一输出信号；第二输入端；以及输出端，用来产生比较输出信号；计数器，连接于该比较器的输出端，用来产生该第二输出信号；参考信号产生器，连接于该第二输入端，用来产生参考信号，该参考信号产生器包含有一随机数生成器，该随机数生成器用来产生随机数，该参考信号相关于该随机数；其该比较器根据该第一输出信号及该参考信号，产生该比较输出信号。本发明提供的输出转换电路具有可改善输出信号的统计线性度的优点。

Description

输出转换电路及指纹识别系统 技术领域
本发明涉及一种输出转换电路及指纹识别系统，尤其涉及一种可改善输出信号的统计线性度的输出转换电路及指纹识别系统。
背景技术
随着科技日新月异，移动电话、数字相机、平板计算机、笔记本电脑等越来越多携带型电子装置已经成为了人们生活中必备之工具。由于携带型电子装置一般为个人使用，而具有一定的隐私性，因此其内部储存的数据，例如电话簿、相片、个人信息等等为私人所有。若电子装置一旦丢失，则这些数据可能会被他人所利用，而造成不必要之损失。虽然目前已有利用密码保护的方式来避免电子装置为他人所使用，但密码容易泄露或遭到破解，具有较低的安全性。并且，用户需记住密码才能使用电子装置，若忘记密码，则会带给使用者许多不便。因此，目前发展出利用个人指纹识别系统的方式来达到身份认证的目的，以提升数据安全性。
一般来说，指纹识别系统中利用像素数组电路接受一手指之接触，像素数组电路将像素数组电路与手指之间之电容转换成像素输出信号，像素输出信号受到噪声的影响，而不具备良好的统计线性度，不利于后端的图像处理。因此，如何改善指纹识别系统的输出信号的统计线性度也就成为业界所努力的目标之一。
发明内容
因此，本发明之主要目的即在于提供一种可改善输出信号的统计线性度的输出转换电路及指纹识别系统。
为了解决上述技术问题，本发明提供了一种输出转换电路，该输出转换电路包括：比较器、计数器、及参考信号产生器；计数器包括：第一输入端，用来接收该第一输出信号；第二输入端；以及输出端，用来产生比较输出信号；计数器，连接于该比较器的输出端，用来产生该第二输出信号；参考信号产生器，连接于该第二输入端，用来产生参考信号，该参考信号产生器包含有一随机数生成器，该随机数生成器用来产生随机数，该参考信号相关于该随机数；其该比较器根据该第一输出信号及该参考信号，产生该比较输出信号。
优选地，该参考信号为随时间而随机变动之信号，该随机数呈均匀分布。
优选地，该参考信号产生器包括控制电路，该控制电路输出参考电压，该参考电压具有固定电压值。
优选地，该参考信号相关于该参考电压与该随机数的总和。
优选地，该参考信号产生器还包括数字模拟转换器，用来将该参考电压与该随机数的总和转换成模拟的该参考信号。
优选地，当第一输出信号大于该参考信号时，该比较输出信号为第一电位，以及当该第一输出信号小于该参考信号时，该比较输出信号为第二电位。
优选地，其用于指纹识别系统，该指纹识别系统包括像素数组电路，该第一输入端连接于该像素数组电路。
优选地，该像素数组电路包括至少一像素电路。
优选地，其中该像素数组电路用来接受手指的接触，并将该像素数组电路与该手指之间形成的电容转换成一像素输出信号，该像素输出信号相关于该第一输出信号。
优选地，该指纹识别系统还包括放大器，该放大器连接于该像素数组电路与该第一输入端之间，用来增强该像素输出信号之信号强度而成为该第一输出信号。
为了更好解决上述技术问题，本发明还提供了一种指纹识别系统，其包括：
像素数组电路，用来接受手指的接触，并将该像素数组电路与该手指之间形成的电容转换成一像素输出信号；
输出转换电路，用来根据第一输出信号，产生第二输出信号，该输出转换电路包括：
比较器，包含有：
第一输入端，用来接收该第一输出信号；
第二输入端；以及
输出端，用来产生一比较输出信号；
计数器，连接于该比较器的输出端，用来产生该第二输出信号；以及
参考信号产生器，连接于该第二输入端，用来产生一参考信号，该参考信号产生器包含有一随机数生成器，该随机数生成器用来产生一随机数，该参考信号相关于该随机数；以及
指纹判断模块，连接于该信号转换电路，用来根据该第二输出信号判断该像素输出信号对应至一纹蜂或一纹谷；
其中，该第一输出信号相关于该像素输出信号，该比较器根据第一输出信号及该参考信号，产生该比较输出信号。
本发明提供的输出转换电路中，其利用随机数生成器改变参考信号的信号值，使得具有不良统计线性度的第一输出信号转换成为具有良好统计线性度的第二输出信号，并将第二输出信号传送至后端图像处理模块，以利后端的图像处理。
附图说明
图1为本发明实施例一输出转换电路的示意图。
图2为本发明实施例一指纹识别系统的示意图。
图3为一噪声的机率密度函数的示意图。
图4为多个高斯函数的示意图。
图5为一和函数的示意图。
图6为第一输出信号的机率密度函数的示意图。
具体实施方式
为了使本发明的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。
请参考图1，图1为本发明实施例一输出转换电路10之示意图。输出转换电路10用来将第一输出信号Vo1转换成为第二输出信号Vo2，输出转换电路10包含有比较器100、计数器102以及参考电压产生器104。比较器100包含有负输入端(标示有「－」号)、正输入端(标示有「+」号)及一输出端，正输入端(即比较器的第一输入端)用来接收第一输出信号Vo1，负输入端(即比较器的第二输入端)连接于参考电压产生器104，用来接收一参考信号VR。比较器100根据第一输出信号Vo1及参考信号VR，产生比较输出信号Vcp并通过输出端输出比较输出信号Vcp，比较输出信号Vcp可为逻辑0或逻辑1。在一实施例中，当第一输出信号Vo1大于参考信号VR时，比较输出信号Vcp为逻辑1(对应于第一电位)；而当第一输出信号Vo1小于参考信号VR时，比较输出信号Vcp为逻辑0(对应于第二电位)。计数器102连接于比较器100的输出端，用来对比较输出信号Vcp进行累加而产生第二输出信号Vo2，即第二输出信号Vo2为比较输出信号Vcp的累加结果。参考电压产生器104包含有一控制电路120、一随机数生成器124及一数字模拟转换器122，控制电路120用来产生数字的一固定电压VF，随机数生成器124用来产生数字的一随机数RD，数字模拟转换器122用来将固定电压VF与随机数RD的一总和转换成模拟的参考信号VR。较佳地，随机数RD呈现一均匀分布(Uniform Distribution)。
输出转换电路10的工作原理叙述如下。第一输出信号Vo1中包含有一有用信号sig及一噪声noi，即第一输出信号Vo1为有用信号sig及噪声noi的相加结果，其数学式子可表示为Vo1＝sig+noi，其中噪声noi可视为一随机变量，而第一输出信号Vo1的一累积密度函数F(a)代表「第一输出信号Vo1小于一特定值a的机率」。需注意的是，因噪声noi通常为一非均匀分布(Non-uniform Distribution)，而使得第一输出信号Vo1的统计线性度不佳，换句话说，对一固定区间Δ来说，固定区间Δ在特定值a附近的机率与固定区间Δ在另一特定值b附近的机率不同，例如F(a+Δ)-F(a)≠F(b+Δ)-F(b)。
换句话说，第一输出信号Vo1统计线性度不佳的主要原因之一为噪声noi呈现非均匀分布，以噪声noi呈现一高斯分布(Gaussian Distribution)为例，如图3所示，噪声noi的一机率密度函数p(x)于中心(x＝0)处具有非均匀性，因此导致第一输出信号Vo1的统计线性度不佳。为了解决机率密度函数的非均匀性问题，可将复数个经过平移过的机率密度函数相互叠加，叠加后的一和函数即可具有均匀分布的特性。具体来说，请参考图4及图5，图4为高斯函数p-N～pN的示意图，图5为一和函数pSUM的示意图。于图4中，高斯函数p0代表中心为0的高斯函数，高斯函数p-N～p-1代表将高斯函数p0向左平移的复数个高斯函数，高斯函数p1～pN代表将高斯函数p0向右平移的复数个高斯函数。需注意的是，和函数pSUM为将高斯函数p-N～pN全部相互叠加之后的结果，由图5可知，和函数pSUM于其中心处具有均匀分布的特性。
另一方面，透过改变参考信号VR的信号值(改变参考信号VR的信号值可由随机数生成器124来执行)，可达到将噪声noi的机率密度函数平移的效果。详细来说，请参考图6，图6为第一输出信号Vo1的一机率密度函数q(x)的示意图。机率密度函数q(x)以第一输出信号Vo1的有用信号sig为中心，比较输出信号Vcp为逻辑0的机率等于第一输出信号Vo1小于参考信号VR的机率(图6中的网状网格线区域)，比较输出信号Vcp为逻辑1的机率即为第一输出信号Vo1大于参考信号VR的机率(图6中的点状分布区域)。实际上，在无法改变 有用信号sig的信号值的情况下，改变参考信号VR的信号值相当于将机率密度函数q(x)或向左或向右平移，详细来说，增加参考信号VR的信号值即相当于将第一输出信号Vo1的机率密度函数向左平移，降低参考信号VR的信号值即相当于将第一输出信号Vo1的机率密度函数向右平移，其中，改变参考信号VR的信号值可透过随机数生成器124来执行。更进一步地，因第二输出信号Vo2为比较输出信号Vcp的累加结果，因此，第二输出信号Vo2的一机率密度函数可视为将机率密度函数q(x)平移后叠加的结果，而具有如图5所示之均匀分布特性，因此第二输出信号Vo2可具有良好的统计线性度。
由上述可知，本发明的输出转换电路10利用随机数生成器124改变参考信号VR的信号值，使得具有不良统计线性度的第一输出信号Vo1转换成为具有良好统计线性度的第二输出信号Vo2，并将第二输出信号Vo2传送至后端图像处理模块，具有良好统计线性度的第二输出信号Vo2有助于后端的图像处理。
另一方面，输出转换电路10可应用于一指纹识别系统。请参考图2，图2为本发明实施例一指纹识别系统20之示意图，指纹识别系统20应用了输出转换电路10，并包含有一像素数组电路22、一放大器24及一指纹判断模块26。像素数组电路22用来接受手指的接触，并将像素数组电路22与手指之间之一接触电容CF转换成一像素输出信号Vo。放大器24连接于像素数组电路22，用来增强像素输出信号Vo之信号强度而成为第一输出信号Vo1，第一输出信号Vo1即为将输出信号Vo经过放大器24增强后的信号。输出转换电路10中比较器100的正输入端连接于放大器24，比较器100根据第一输出信号Vo1及参考信号VR，产生比较输出信号Vcp。输出转换电路10用来将统计线性度不良的第一输出信号Vo1转换成统计线性度良好的第二输出信号Vo2，第二输出信号Vo2输出至指纹判断模块26，指纹判断模块26根据第二输出信号Vo2判断像素输出信号Vo对应至一纹蜂(Finger Ridge)或一纹谷(Finger Valley)。
需注意的是，前述实施例系用以说明本发明之概念，本领域具通常知识者当可据以做不同之修饰，而不限于此。举例来说，放大器24仅用来增强像素输 出信号Vo之信号强度，而不限于此，在像素输出信号之信号强度足够的情况下，指纹识别系统可将比较器的正输入端直接连接于像素数组电路，亦属于本发明之范畴。另外，随机数生成器可利用一扰动器(Dither)来实现，而不在此限。
综上所述，本发明利用随机数生成器改变参考信号的信号值，使得具有不良统计线性度的第一输出信号转换成为具有良好统计线性度的第二输出信号，并将第二输出信号传送至后端图像处理模块，以利后端的图像处理。
以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。

Claims (17)

  1. 一种输出转换电路，用来根据第一输出信号，产生第二输出信号，其特征在于，所述输出转换电路包括：
    比较器，包含有：
    第一输入端，用来接收该第一输出信号；
    第二输入端；以及
    输出端，用来产生比较输出信号；
    计数器，连接于该比较器的输出端，用来产生该第二输出信号；以及
    参考信号产生器，连接于该第二输入端，用来产生参考信号，该参考信号产生器包含有一随机数生成器，该随机数生成器用来产生随机数，该参考信号相关于该随机数；
    其中，该比较器根据该第一输出信号及该参考信号，产生该比较输出信号。
  2. 如权利要求1所述的输出转换电路，其特征在于，该参考信号为随时间而随机变动之信号，该随机数呈均匀分布。
  3. 如权利要求1所述的输出转换电路，其特征在于，该参考信号产生器包括控制电路，该控制电路输出参考电压，该参考电压具有固定电压值。
  4. 如权利要求3所述的输出转换电路，其特征在于，该参考信号相关于该参考电压与该随机数的总和。
  5. 如权利要求4所述的输出转换电路，其特征在于，该参考信号产生器还包括数字模拟转换器，用来将该参考电压与该随机数的总和转换成模拟的该参考信号。
  6. 如权利要求1所述的输出转换电路，其特征在于，当第一输出信号大于该参考信号时，该比较输出信号为第一电位，以及当该第一输出信号小于该参考信号时，该比较输出信号为第二电位。
  7. 如权利要求1所述的输出转换电路，其特征在于，其用于指纹识别系统，该指纹识别系统包括像素数组电路，该第一输入端连接于该像素数组电路。
  8. 如权利要求7所述的输出转换电路，其特征在于，该像素数组电路包括至少一像素电路。
  9. 如权利要求7所述的输出转换电路，其特征在于，其中该像素数组电路用来接受手指的接触，并将该像素数组电路与该手指之间形成的电容转换成一像素输出信号，该像素输出信号相关于该第一输出信号。
  10. 如权利要求9所述的输出转换电路，其特征在于，该指纹识别系统还包括放大器，该放大器连接于该像素数组电路与该第一输入端之间，用来增强该像素输出信号之信号强度而成为该第一输出信号。
  11. 一种指纹识别系统，包含有：
    像素数组电路，用来接受手指的接触，并将该像素数组电路与该手指之间形成的电容转换成一像素输出信号；
    输出转换电路，用来根据第一输出信号，产生第二输出信号，该输出转换电路包括：
    比较器，包含有：
    第一输入端，用来接收该第一输出信号；
    第二输入端；以及
    输出端，用来产生一比较输出信号；
    计数器，连接于该比较器的输出端，用来产生该第二输出信号；以及
    参考信号产生器，连接于该第二输入端，用来产生一参考信号，该参考信号产生器包含有一随机数生成器，该随机数生成器用来产生一随机数，该参考信号相关于该随机数；以及
    指纹判断模块，连接于该信号转换电路，用来根据该第二输出信号判断该像素输出信号对应至一纹蜂或一纹谷；
    其中，该第一输出信号相关于该像素输出信号，该比较器根据第一输出信号及该参考信号，产生该比较输出信号。
  12. 如权利要求11所述的指纹识别系统，其特征在于，该参考信号为随时间而随机变动之信号，该随机数呈均匀分布。
  13. 如权利要求11所述的指纹识别系统，其特征在于，该参考信号产生器包括控制电路，该控制电路输出参考电压，该参考电压具有固定电压值。
  14. 如权利要求13所述的指纹识别系统，其特征在于，该参考信号相关于该参考电压与该随机数的总和。
  15. 如权利要求14所述的指纹识别系统，其特征在于，该参考信号产生器还包括数字模拟转换器，用来将该参考电压与该随机数的总和转换成模拟的该参考信号。
  16. 如权利要求11所述的指纹识别系统，其特征在于，当第一输出信号大于该参考信号时，该比较输出信号为第一电位，以及当该第一输出信号小于该参考信号时，该比较输出信号为第二电位。
  17. 如权利要求11所述的指纹识别系统，其特征在于，该像素数组电路包括至少一像素电路。
PCT/CN2016/071681 2015-10-21 2016-01-21 输出转换电路及指纹识别系统 WO2017067109A1 (zh)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1801627A (zh) * 2004-10-11 2006-07-12 因芬尼昂技术股份公司 模数转换器
CN101344917A (zh) * 2007-07-13 2009-01-14 晨星半导体股份有限公司 指纹检测电路
CN104298962A (zh) * 2014-09-04 2015-01-21 深圳市汇顶科技股份有限公司 指纹检测装置和方法
CN104393856A (zh) * 2014-10-24 2015-03-04 深圳市汇顶科技股份有限公司 一种斜坡波产生电路及其数模转换电路、指纹识别系统

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004077669A1 (ja) * 2003-02-28 2004-09-10 Matsushita Electric Industrial Co., Ltd. 確率的パルス発生器と差分絶対値演算器及びこれを用いたマンハッタン距離演算装置
US7224305B2 (en) * 2004-06-08 2007-05-29 Telefonaktiebolaget L M Ericsson (Publ) Analog-to-digital modulation
US7472148B2 (en) * 2004-07-23 2008-12-30 Qualcomm Incorporated Method and apparatus for random-number generator
KR100828128B1 (ko) * 2006-07-20 2008-05-09 에이디반도체(주) 시분할 복수 주파수를 이용하는 정전용량 검출방법 및검출장치
TWI397862B (zh) * 2007-06-22 2013-06-01 Mstar Semiconductor Inc 指紋偵測器
JP2012195734A (ja) * 2011-03-16 2012-10-11 Sony Corp 固体撮像装置、撮像装置、電子機器、及び、固体撮像装置の駆動方法
KR101613123B1 (ko) * 2014-04-10 2016-04-18 크루셜텍 (주) 지문 검출 장치 및 이의 구동 신호 감쇄 보상 방법
CN104133658A (zh) * 2014-07-29 2014-11-05 江苏宏云技术有限公司 一种片内真随机数生成器

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1801627A (zh) * 2004-10-11 2006-07-12 因芬尼昂技术股份公司 模数转换器
CN101344917A (zh) * 2007-07-13 2009-01-14 晨星半导体股份有限公司 指纹检测电路
CN104298962A (zh) * 2014-09-04 2015-01-21 深圳市汇顶科技股份有限公司 指纹检测装置和方法
CN104393856A (zh) * 2014-10-24 2015-03-04 深圳市汇顶科技股份有限公司 一种斜坡波产生电路及其数模转换电路、指纹识别系统

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3206159A4 *

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