CN111027516B - Biological characteristic image acquisition device, biological characteristic image acquisition method and intelligent equipment - Google Patents
Biological characteristic image acquisition device, biological characteristic image acquisition method and intelligent equipment Download PDFInfo
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- 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
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Abstract
The embodiment of the application provides a device and a method for acquiring biological characteristic images and intelligent equipment, and belongs to the technical field of image acquisition. The device comprises: a gate switch for outputting a gate signal; the photoelectric sensing unit is connected with the gating switch and used for receiving the gating signal, gating the photoelectric device of the appointed pixel point and converting the biological characteristic optical signal acquired by the photoelectric device into a charge signal; the charge compensation circuit is used for outputting compensation signals corresponding to the appointed pixel points; and the signal processing circuit is connected with the output ends of the photoelectric sensing unit and the charge compensation circuit and is used for receiving the charge signal and the compensation signal, superposing the compensation signal on the basis of the charge signal to obtain an effective charge signal, and converting the effective charge signal into a pixel value of a designated pixel point. According to the technical scheme provided by the embodiment of the application, the accuracy of the acquired biological characteristic image can be improved, and the influence of interference signals is removed.
Description
Technical Field
The application relates to the technical field of characteristic information acquisition, in particular to a biological characteristic image acquisition device and method, intelligent equipment and display equipment.
Background
With the increasing demands of people for information security, biometric technology is receiving more and more attention from various circles. Among many biometric technologies, fingerprint identification technology has become one of the most widely used technologies with the highest interest due to its practical applicability, and particularly, fingerprint identification has become an indispensable part for handheld mobile devices such as mobile phones and tablet computers.
As shown in fig. 1, at present, fingerprint images are acquired mainly by placing a finger 104 on a screen 102, wherein a light ray emitted by a light source 101 is built in the screen 102, a part of the light ray is reflected by the finger, and a fingerprint image acquisition module 103 acquires a reflected light signal and processes the light signal to generate the fingerprint images.
When the built-in light source 101 is a point light source, the image has a characteristic that the center of the light source is bright and the edges are dark (as shown by the pattern 22 in fig. 2 a). In the actual fingerprint image acquisition process, an effective signal (a sine wave 23 shown in B in fig. 2) is superimposed on a low-frequency ground trace (a triangular wave 21 shown in a in fig. 2), so that the acquisition of a fingerprint image is interfered, and the accuracy of the fingerprint image is reduced.
Disclosure of Invention
An object of the embodiments of the present application is to provide a device for acquiring a biometric image, so as to improve accuracy of the biometric image.
The embodiment of the application provides a collection device of biological characteristic image, including:
the gating switch is used for controlling gating signal output;
the photoelectric sensing unit is connected with the gating switch and is used for receiving the gating signal, gating a photoelectric device of a designated pixel point and converting a biological characteristic optical signal acquired by the photoelectric device into a charge signal;
the charge compensation circuit is used for outputting compensation signals corresponding to the appointed pixel points;
and the signal processing circuit is connected with the output ends of the photoelectric sensing unit and the charge compensation circuit and is used for receiving the charge signal and the compensation signal, superposing the compensation signal on the basis of the charge signal to obtain an effective charge signal, and converting the effective charge signal into the pixel value of the appointed pixel point.
In one embodiment, the charge compensation circuit includes:
the storage module is used for storing compensation data corresponding to different compensation indexes;
the control module is used for calculating the position relation between the appointed pixel point and the reference point to obtain a compensation index; the compensation data corresponding to the compensation index is obtained from the storage module, and the compensation data is output;
and the charge compensation module is connected with the control module and the signal processing circuit and is used for receiving the compensation data output by the control module, converting the compensation data into a compensation signal and inputting the compensation signal into the signal processing circuit.
In one embodiment, the charge compensation module comprises:
the digital-to-analog converter is connected with the control module and is used for receiving the compensation data output by the control module and converting the compensation data into an analog voltage signal;
and the compensating capacitor is connected with the digital-to-analog converter, and the analog voltage signal is converted into a compensating signal by the analog voltage signal.
In an embodiment, the charge compensation module further comprises:
a first switch connected to the digital-to-analog converter and the compensation capacitor, the first switch being closed when charge compensation is performed, conduction between the digital-to-analog converter and the compensation capacitor being performed; the first switch is opened at initialization;
and the second switch is connected with the compensation capacitor, is opened during charge compensation, is closed during initialization, and charges in the compensation capacitor are released from a branch where the second switch is located.
In one embodiment, the signal processing circuit includes:
the charge amplifier is connected with the output ends of the photoelectric sensing unit and the charge compensation circuit and is used for receiving the charge signal and the compensation signal, superposing the compensation signal on the basis of the charge signal to obtain an effective charge signal, and converting the effective charge signal into an amplified voltage signal;
the voltage amplifier is connected with the output end of the charge amplifier and is used for amplifying the voltage signal;
and the analog-to-digital converter is connected with the output end of the voltage amplifier and is used for converting the amplified voltage signal into the pixel value of the appointed pixel point.
In an embodiment, the voltage amplifier comprises:
the nonlinear amplifier is connected with the output end of the charge amplifier and is used for carrying out nonlinear transformation on the amplified voltage signal and compressing the signal range;
and the linear amplifier is connected with the output end of the nonlinear amplifier and the input end of the analog-to-digital converter and is used for linearly amplifying the compressed voltage signal and inputting the compressed voltage signal into the analog-to-digital converter.
In an embodiment, the voltage amplifier comprises:
the linear amplifier is connected with the output end of the charge amplifier and is used for linearly amplifying the received voltage signal;
and the nonlinear amplifier is connected with the output end of the linear amplifier and the input end of the analog-to-digital converter and is used for carrying out nonlinear conversion on the voltage signal subjected to linear amplification, compressing the signal range and then inputting the voltage signal into the analog-to-digital converter.
The embodiment of the application also provides a method for acquiring the biological characteristic image, which comprises the following steps:
scanning pixel points sequentially, collecting biological characteristic optical signals corresponding to the pixel points, and converting the biological characteristic optical signals into charge signals;
determining a compensation signal corresponding to the pixel point according to the position of the pixel point;
superposing the compensation signal on the basis of the charge signal to obtain an effective charge signal;
converting the effective charge signal into a pixel value corresponding to the pixel point;
and obtaining a biological characteristic image based on the pixel value corresponding to each pixel point.
In an embodiment, the determining the compensation signal corresponding to the pixel according to the position of the pixel includes:
calculating the position relation between the pixel point and the reference point according to the position of the pixel point to obtain a compensation index;
and obtaining compensation data corresponding to the compensation index, and converting the compensation data into the compensation signal.
In an embodiment, the position relationship is a euclidean distance between the pixel point and the reference point, and the obtaining the compensation data corresponding to the compensation index includes:
and calculating compensation data corresponding to the compensation index according to a preset compensation curve.
In an embodiment, calculating a positional relationship between the pixel point and a reference point according to the position of the pixel point to obtain a compensation index includes:
calculating the difference value between the abscissa of the pixel point and the abscissa of the reference point to obtain a line difference; calculating the difference between the ordinate of the pixel point and the ordinate of the reference point to obtain a column difference; wherein the row and column differences constitute the compensation index;
the obtaining the compensation data corresponding to the compensation index includes: and acquiring compensation data corresponding to the compensation index from a preset compensation matrix.
In addition, the embodiment of the application also provides an intelligent device, which comprises:
a cover plate;
the light source is internally arranged in the intelligent equipment and used for emitting light rays to irradiate a target object contacting the cover plate;
the collecting device of the biological characteristic image collects biological characteristic optical signals emitted by the light source and reflected by the target object.
Further, an embodiment of the present application further provides a display device, including:
a display panel for emitting light rays to irradiate a target object contacting the display panel;
the device for acquiring the biological characteristic image acquires the biological characteristic optical signal which is emitted by the display panel and reflected by the target object.
In an embodiment, the display panel is any one of an OLED panel, an LED panel, and an LCD panel.
According to the technical scheme provided by the embodiment of the application, the charge compensation circuit outputs the compensation signal corresponding to each pixel point, and after the charge signal collected by the photoelectric sensing unit is overlapped with the compensation signal, the influence of interference charge is eliminated, the effective charge signal of the biological feature can be obtained, the effective charge signal is converted into the pixel value to be output, the accuracy of the collected biological feature image can be improved, and the influence of the interference signal is removed.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following description will briefly explain the drawings that are required to be used in the embodiments of the present application.
FIG. 1 is a schematic view of the collection range of a point light source in the background art;
FIG. 2 is a schematic diagram of a fingerprint image generated in the background art;
fig. 3 is a schematic structural diagram of a device for acquiring a biometric image according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of a device for acquiring a biometric image according to an embodiment of the present application;
FIG. 5 is a schematic diagram of a compensation curve provided in an embodiment of the present application;
FIG. 6 is a circuit diagram illustrating a connection between a charge compensation module and a signal processing circuit according to an embodiment of the present disclosure;
fig. 7 is a schematic structural diagram of a signal processing circuit according to an embodiment of the present disclosure;
fig. 8 is a schematic structural diagram of a signal processing circuit according to another embodiment of the present disclosure;
FIG. 9 is a schematic circuit diagram of a nonlinear amplifier according to an embodiment of the present application;
fig. 10 is a schematic circuit diagram of a device for acquiring a biometric image according to an embodiment of the present application;
FIG. 11 is a flowchart of a method for acquiring a biometric image according to an embodiment of the present disclosure;
fig. 12 is a flowchart of a method for acquiring a biometric image according to another embodiment of the present application based on fig. 11.
Detailed Description
The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.
Like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
Fig. 3 is a schematic structural diagram of a device 100 for acquiring a biometric image according to an embodiment of the present application, and as shown in fig. 3, the device 100 includes: a gate switch 31, a photo-sensing unit 32, a charge compensation circuit 33, and a signal processing circuit 34.
Wherein the gating switch 31 is used for outputting a gating signal. The strobe signal may include a row strobe signal for indicating a row of the strobe and a column strobe signal for indicating a column of the strobe, and the pixel point of the strobe may be determined based on an intersection of the row and the column. In one embodiment, the strobe signal output by the strobe switch 31 may be high to the strobed row and high to the strobed column, with the other rows and columns outputting low.
In an embodiment, the gating switch 31 may be connected to a controller, and the controller may output a pulse signal at preset time intervals, so as to trigger the gating switch 31 to output a high level to a certain row and a certain column sequentially, and gate the rows and the columns sequentially.
Wherein the photo-sensing unit 32 is connected to the gating switch 31. The photoelectric sensing unit 32 may receive a gate signal of the gate switch 31, gate a photoelectric device of a designated pixel point, and convert a biological characteristic optical signal collected by the photoelectric device into a charge signal. The photo-sensing unit 32 may be a CCD (Charge-coupled Device) or CMOS (Complementary Metal Oxide Semiconductor ) image sensor. The photo-sensing unit 32 may be considered as a plurality of photo-electric devices arranged in an array. One pixel point may be considered to correspond to one photoelectric device, and each photoelectric device may be constituted by a field effect transistor and a photodiode.
In one embodiment, the strobe signal is a high output to the x-th row and a high output to the y-th column, i.e., the optoelectronic device of the pixel is strobed (x, y). The optoelectronic device of the pixel point can convert the collected biological characteristic optical signals into charge signals. The biometric feature may be a fingerprint or a palm print. The biometric light signal may be light reflected from a light source that impinges on a surface of a finger or palm.
The charge compensation circuit 33 is connected to the output end of the photo-sensing unit 32 and the input end of the signal processing circuit 34, and the charge compensation circuit 33 can output a compensation signal corresponding to a specified pixel point. Normally, the brightness of the point light source is fixed every time, and the brightness decay curve is also fixed, so that the interference signal (i.e., the triangular wave 21 of a in fig. 2) is the same every time the effective signal of the fingerprint is acquired, but since the interference signal is the same every time the effective signal is acquired, the interference signal can be removed by calculating the compensation signal of each pixel point, and only the effective signal remains. In an embodiment, the magnitude of the compensation signal for each pixel point may be calculated and stored in advance. In performing biometric image acquisition, the charge compensation circuit 33 may output a compensation signal based on the stored compensation data.
The signal processing circuit 34 is connected to the output ends of the photoelectric sensing unit 32 and the charge compensation circuit 33, and is configured to receive a charge signal and a compensation signal, superimpose the compensation signal on the charge signal to obtain an effective charge signal, and convert the effective charge signal into a pixel value of the specified pixel point.
The charge signal may be considered to include both the effective signal and the interfering signal. After adding the supplementary charge on the basis of the charge signal, it can be considered that the influence of the interference signal is eliminated, and only the effective signal is left. The charge signal from which the interference is eliminated is referred to as an effective charge signal in the embodiment of the present application. The signal processing circuit 34 may convert the effective charge signal into a pixel value for output, and by gating each pixel, the pixel value of each pixel, that is, the biometric image, may be obtained. The pixel value is the gray value of the pixel point and is in the range of 0-255.
Fig. 4 is a schematic structural diagram of a biometric image acquisition device 100 according to another embodiment of the present application, and as shown in fig. 4, the charge compensation circuit 33 may include: a memory module 331, a control module 332, and a charge compensation module 333.
The storage module 331 is configured to store compensation data corresponding to different compensation indexes. Fig. 5 is a compensation curve, and as shown in fig. 5, the value of each compensation index may correspond to one compensation data (i.e., the compensation parameter on the ordinate).
The control module 332 is configured to calculate a compensation index obtained by calculating a positional relationship between a specified pixel point and a reference point, and obtain compensation data corresponding to the compensation index from the storage module 331, and further output the compensation data to the charge compensation module 333. The reference point refers to the position (x 0 ，y 0 ) Since the point source position is unchanged, the position of the reference point can be considered as a known quantity.
In one embodiment, a pixel point (x, y) is assigned to a reference point (x 0 ，y 0 ) The positional relationship of (c) may be euclidean distance r=sqrt ((x-x) 0 ) 2 +(y-y 0 ) 2 ) (x, y) represents the position coordinates of the specified pixel point, and the euclidean distance r can be regarded as a compensation index. The control module 332 may obtain compensation data corresponding to the distance r from the storage module 331 according to the distance r. The compensation data is the compensation data corresponding to the distance r (compensation index) on the compensation curve corresponding to fig. 5.
In another embodiment, a pixel point (x, y) is assigned to a reference point (x 0 ，y 0 ) The positional relationship of (2) can be represented by a row and column difference (x ', y'). (x ', y') = (x-x) 0 ，y-y 0 ). At this point (x ', y') can be considered as the compensation index. The compensation data corresponding to the compensation index can be obtained by extracting (x ', y') positions from a compensation matrixThe value of the (x ', y') position is taken as compensation data. The compensation data corresponding to the different compensation indexes may be calculated in advance and stored in the storage module 331.
The charge compensation module 333 is connected to the control module 332 and the signal processing circuit 34, and is configured to receive the compensation data output by the control module 332, convert the compensation data into a compensation signal, and input the compensation signal to the signal processing circuit 34.
In one embodiment, as shown in fig. 6, the charge compensation module 333 may include a digital-to-analog converter DAC and a compensation capacitor C. The input end of the digital-to-analog converter is connected with the control module 332 for receiving the compensation data D outputted by the control module 332 xy . The DAC converts the compensation data into an analog voltage signal U D And outputting.
The output end of the digital-to-analog converter DAC is connected with one end of the compensation capacitor C, and corresponding compensation signals are accumulated on the compensation capacitor C. Compensation signal q=cu on compensation capacitor C D . Wherein U is D Representing an analog voltage signal. The other end of the compensation capacitor C is connected to the input of the signal processing circuit 34 and the output of the opto-electronic device 321 in the opto-electronic sensing unit 32. Thereby inputting the compensation signal to the signal processing circuit 34.
As shown in fig. 6, the signal processing circuit 34 may include a charge amplifier 341, a voltage amplifier 342, and an analog-to-digital converter 343, which are sequentially connected. The charge amplifier 341 may receive the charge signal output by the optoelectronic device 321 and may also receive the compensation signal output by the charge compensation module 333. The charge signal and the compensation signal are added together (i.e., the effective charge signal) and then input to the inverting input of the charge amplifier 341. The charge amplifier 341 converts the effective charge signal into an amplified voltage signal. The voltage amplifier 342 amplifies the voltage signal, and the analog-to-digital converter 343 converts the amplified voltage signal into a digital signal, that is, a pixel value of the photoelectric device 321 corresponding to the pixel point (x, y).
In an embodiment, as shown in fig. 6, the charge compensation module 333 may further include: first switch S xy And a second switch N. First switch S xy One end of which is connected to a digital-to-analog converter DAC,the other end is connected with the compensation capacitor C. The second switch N may be an N-type field effect transistor, in which a gate inputs a reset signal (Rst), a source is connected to the compensation capacitor C, and a drain is connected to a reference voltage.
When Ty is input with high level and the photoelectric device 321 of the designated pixel is turned on, the first switch S indicates that charge compensation is required for the designated pixel xy The Rst signal is closed low (i.e., the branch in which the second switch N is located is open). So that the digital-to-analog converter DAC is conducted with the compensation capacitor C, and charges are accumulated on the compensation capacitor C. When Ty is input low, the electro-optical device 321 of the designated pixel is not turned on, and initialization is indicated. First switch S xy The Rst signal is turned off and high (i.e., the branch in which the second switch N is located is turned on), thereby discharging the charge in the compensation capacitor C.
In one embodiment, as shown in fig. 7, the voltage amplifier 342 may include: a nonlinear amplifier 3421 and a linear amplifier 3422. An input of the non-linear amplifier 3421 may be connected to an output of the charge amplifier 341. An output of the non-linear amplifier 3421 may be connected to an input of the linear amplifier 3422. The output of the linear amplifier 3422 is connected to the input of the analog-to-digital converter 343.
The charge amplifier 341 is connected to the output ends of the photoelectric sensing unit 32 and the charge compensation circuit 33, and is configured to receive the charge signal and a compensation signal, superimpose the compensation signal on the charge signal to obtain an effective charge signal, and convert the effective charge signal into an amplified voltage signal; the nonlinear amplifier 3421 is connected to the output end of the charge amplifier 341 and is used for performing nonlinear transformation on the amplified voltage signal and compressing a signal range; a linear amplifier 3422 connected to the output of the nonlinear amplifier 3421 for linearly amplifying the compressed voltage signal; the analog-to-digital converter 343 is connected to the output end of the linear amplifier 3422 and is configured to convert the voltage signal after linear amplification into the pixel value of the specified pixel point.
In another embodiment, as shown in fig. 8, a nonlinear amplifier 3421 may be located between the linear amplifier 3422 and the analog-to-digital converter 343, where an input terminal of the nonlinear amplifier 3421 is connected to an output terminal of the linear amplifier 3422, and an output terminal of the nonlinear amplifier 3421 is connected to an input terminal of the analog-to-digital converter 343.
The charge amplifier 341 is connected to the output ends of the photoelectric sensing unit 32 and the charge compensation circuit 33, and is configured to receive the charge signal and the compensation signal, superimpose the compensation signal on the charge signal to obtain an effective charge signal, and convert the effective charge signal into an amplified voltage signal; a linear amplifier 3422 connected to the output of the charge amplifier 341 for amplifying the voltage signal; the nonlinear amplifier 3421 is connected to the output end of the linear amplifier 3422, and is used for performing nonlinear transformation on the amplified voltage signal and compressing the signal range; the analog-to-digital converter 343 is connected to the output terminal of the nonlinear amplifier 3421 and is used for converting the compressed voltage signal into the pixel value of the specified pixel point.
In an embodiment, the linear amplifier 3422 may be an operational amplifier based negative feedback amplifier, a differential amplifier. The instrumentation amplifier belongs to an improvement of the differential amplifier, and can also be used as a linear amplifier 3422. The nonlinear amplifier 3421 may be a logarithmic amplifier, an exponential amplifier, and a power operation amplifying circuit. For example, the structure of the logarithmic amplifier may be as shown in fig. 9. The output voltage and the input voltage satisfy:
wherein U is T And I S Are constant only in relation to the process of the transistor T.
The voltage signal is subjected to nonlinear transformation through the nonlinear amplifier 3421, and the signal range is compressed, so that the acquired signal is more uniform, the dynamic range of the acquisition device 100 is enlarged, and the acquisition precision is improved.
In an embodiment, as shown in fig. 10, the gate switch 31 may be a row gate switch 311, and may sequentially output a high level to each row, thereby sequentially gating one row of the optoelectronic devices 321. The controller 35 may output a pulse signal to the row strobe switch 311 at a timing, triggering the row strobe switch 311 to output a row strobe signal at a corresponding frequency. The optoelectronic devices 321 of the same row may be correspondingly connected to a set of signal processing circuits 34 and charge compensation circuits 33. The same column of opto-electronic devices 321 may be connected to the same set of signal processing circuitry 34 and charge compensation circuitry 33.
For example, T 1 The gate signal of the 1 st row, P11 is the 1 st column, the 1 st row of photodiodes, when T1 is high, all photodiodes P11, P12 of the 1 st row,. Similarly, the pixel value of each pixel point can be obtained, and a biological characteristic image (such as a fingerprint image) is obtained.
Fig. 11 is a flowchart of a method for acquiring a biometric image according to an embodiment of the present application, which may be performed by the apparatus 100 for acquiring a biometric image as described above. As shown in fig. 11, the acquisition method may include the following steps 1110-1150.
In step 1110, scanning pixel points sequentially, collecting a biological characteristic optical signal corresponding to the pixel points, and converting the biological characteristic optical signal into a charge signal;
in one embodiment, the biometric light signal may be collected by the photo-sensing unit 32 and converted into a charge signal. The photo-sensing unit 32 may receive a strobe signal to strobe a specified pixel, i.e., to perform a scan of the pixel. The photo-sensing unit 32 may receive a row strobe signal and a column strobe signal to strobe the photo-electric device 321 of the corresponding pixel. By continuously updating the row strobe signal and the column strobe signal, scanning of all pixel points can be completed.
The optoelectronic device 321 of each pixel point gate can collect the biological characteristic optical signal and convert the biological characteristic optical signal into an electrical signal.
In step 1120, according to the position of the pixel, a compensation signal corresponding to the pixel is determined. In an embodiment, the corresponding compensation signal may be determined by the charge compensation circuit 33 according to the position of the pixel point.
In step 1130, the compensation signal is superimposed on the charge signal to obtain an effective charge signal. In an embodiment, the input terminals of the signal processing circuit 34 may be connected to the photoelectric sensing unit 32 and the charge compensation circuit 33, respectively, to receive the charge signal and the compensation signal. The superposition of the charge signal and the compensation signal can be considered to cancel the disturbing charge, resulting in an effective charge signal.
In step 1140, the effective charge signal is converted into a pixel value corresponding to the pixel point. In an embodiment, the signal processing circuit 34 may include a charge amplifier 341, a voltage amplifier 342, and an analog-to-digital converter 343 connected in sequence. The charge amplifier 341 converts the effective charge signal into an amplified voltage signal. The voltage amplifier 342 linearly amplifies the amplified voltage signal. The analog-to-digital converter 343 converts the linearly amplified voltage signal into a pixel value to be output.
In step 1150, a biometric image is obtained based on the pixel values corresponding to each pixel.
In one embodiment, as shown in FIG. 12, the above step 1120 may include the following steps 1121-1122.
In step 1121, according to the position of the pixel point, the position relationship between the pixel point and the reference point is calculated, and the compensation index is obtained.
The reference point refers to the position of the center of the light source in the image. In one embodiment, the control module 332 of the charge compensation circuit 33 can calculate the positional relationship between the pixel point and the reference point. Pixel point (x, y) and reference point (x 0 ，y 0 ) The position relation of the pixel point and the reference point can be Euclidean distance, and the position relation of the pixel point and the reference point can also be used for representing the row difference of the pixel point and the reference point and the column difference of the pixel point and the reference point. In an embodiment, the compensation index may be euclidean distance r=sqrt ((x-x) 0 ) 2 +(y-y 0 ) 2 ). In another embodimentIn an example, the compensation index may be expressed by a row and column difference (x ', y'). (x ', y') = (x-x) 0 ，y-y 0 ). x 'represents the difference between the abscissa of the pixel point and the abscissa of the reference point, and y' represents the difference between the ordinate of the pixel point and the ordinate of the reference point.
In step 1122, compensation data corresponding to the compensation index is obtained, and the compensation data is converted into the compensation signal.
In an embodiment, the control module 332 may calculate the compensation data corresponding to the compensation index according to a preset compensation curve. In another embodiment, the control module 332 may obtain the value of the position where (x ', y') is located, that is, the compensation data corresponding to the compensation index, from the preset compensation matrix.
In an embodiment, the charge compensation module 333 in the above embodiment may convert the compensation data into the compensation signal, and the embodiment corresponding to fig. 6 may be referred to herein, and will not be described again.
The embodiment of the application also provides intelligent equipment, which can be a smart phone, a tablet computer, a fingerprint lock or a fingerprint attendance machine and the like.
The intelligent device comprises a cover plate, a light source and a biological characteristic image acquisition device 100 provided by the embodiment of the application. The light source is arranged in the intelligent equipment and used for emitting light rays to irradiate a target object contacting the cover plate; the target object may be a finger or palm, or the like. The acquisition device 100 acquires the biological characteristic optical signal emitted by the light source and reflected by the target object, and converts the optical signal into a pixel value to obtain a biological characteristic image.
In one embodiment, a display panel may be used as the cover plate and the light source. The smart device may be a display device, and the display panel may be any one of an OLED (organic light-Emitting Diode) panel, an LED (Light Emitting Diode ) panel, and an LCD (Liquid Crystal Display, liquid crystal display) panel. The display panel can emit light rays to irradiate a target object contacting the display panel; the device 100 for acquiring a biological characteristic image provided in the embodiment of the present application may acquire a biological characteristic optical signal reflected by a target object and sent out by a display panel, and convert the optical signal into a pixel value for outputting through a series of processes.
In the several embodiments provided in the present application, the disclosed apparatus and method may be implemented in other manners. The apparatus embodiments described above are merely illustrative, for example, flow diagrams and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
In addition, the functional modules in the embodiments of the present application may be integrated together to form a single part, or each module may exist alone, or two or more modules may be integrated to form a single part.
The functions, if implemented in the form of software functional modules and sold or used as a stand-alone product, may be stored on a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
Claims (12)
1. A biometric image acquisition device, comprising:
the gating switch is used for controlling gating signal output;
the photoelectric sensing unit is connected with the gating switch and is used for receiving the gating signal, gating a photoelectric device of a designated pixel point and converting an optical signal which is acquired by the photoelectric device and contains biological characteristics into a charge signal;
the charge compensation circuit is used for outputting compensation signals corresponding to the appointed pixel points;
the signal processing circuit is connected with the output ends of the photoelectric sensing unit and the charge compensation circuit and is used for receiving the charge signal and the compensation signal, superposing the compensation signal on the basis of the charge signal to obtain an effective charge signal, and converting the effective charge signal into a pixel value of the appointed pixel point;
wherein the charge compensation circuit includes:
the storage module is used for storing compensation data corresponding to different compensation indexes;
the control module is used for calculating the position relation between the appointed pixel point and the reference point to obtain a compensation index; the compensation data corresponding to the compensation index is obtained from the storage module, and the compensation data is output;
and the charge compensation module is connected with the control module and the signal processing circuit and is used for receiving the compensation data output by the control module, converting the compensation data into a compensation signal and inputting the compensation signal into the signal processing circuit.
2. The apparatus of claim 1, wherein the charge compensation module comprises:
the digital-to-analog converter is connected with the control module and is used for receiving the compensation data output by the control module and converting the compensation data into an analog voltage signal;
and the compensating capacitor is connected with the digital-to-analog converter, and the analog voltage signal is converted into a compensating signal by the analog voltage signal.
3. The apparatus of claim 2, wherein the charge compensation module further comprises:
a first switch connected to the digital-to-analog converter and the compensation capacitor, the first switch being closed when charge compensation is performed, conduction between the digital-to-analog converter and the compensation capacitor being performed; the first switch is opened at initialization;
and the second switch is connected with the compensation capacitor, is opened during charge compensation, is closed during initialization, and charges in the compensation capacitor are released from a branch where the second switch is located.
4. The apparatus of claim 1, wherein the signal processing circuit comprises:
the charge amplifier is connected with the output ends of the photoelectric sensing unit and the charge compensation circuit and is used for receiving the charge signal and the compensation signal, superposing the compensation signal on the basis of the charge signal to obtain an effective charge signal, and converting the effective charge signal into an amplified voltage signal;
the voltage amplifier is connected with the output end of the charge amplifier and is used for amplifying the voltage signal;
and the analog-to-digital converter is connected with the output end of the voltage amplifier and is used for converting the amplified voltage signal into the pixel value of the appointed pixel point.
5. The apparatus of claim 4, wherein the voltage amplifier comprises:
the nonlinear amplifier is connected with the output end of the charge amplifier and is used for carrying out nonlinear transformation on the amplified voltage signal and compressing the signal range;
and the linear amplifier is connected with the output end of the nonlinear amplifier and the input end of the analog-to-digital converter and is used for linearly amplifying the compressed voltage signal and inputting the compressed voltage signal into the analog-to-digital converter.
6. The apparatus of claim 4, wherein the voltage amplifier comprises:
the linear amplifier is connected with the output end of the charge amplifier and is used for linearly amplifying the received voltage signal;
and the nonlinear amplifier is connected with the output end of the linear amplifier and the input end of the analog-to-digital converter and is used for carrying out nonlinear conversion on the voltage signal subjected to linear amplification, compressing the signal range and then inputting the voltage signal into the analog-to-digital converter.
7. A method for acquiring a biometric image, comprising:
scanning pixel points sequentially, collecting biological characteristic optical signals corresponding to the pixel points, and converting the biological characteristic optical signals into charge signals;
determining a compensation signal corresponding to the pixel point according to the position of the pixel point;
superposing the compensation signal on the basis of the charge signal to obtain an effective charge signal;
converting the effective charge signal into a pixel value corresponding to the pixel point;
obtaining a biological characteristic image based on the pixel value corresponding to each pixel point;
wherein, the determining the compensation signal corresponding to the pixel point according to the position of the pixel point includes:
calculating the position relation between the pixel point and the reference point according to the position of the pixel point to obtain a compensation index;
and obtaining compensation data corresponding to the compensation index, and converting the compensation data into the compensation signal.
8. The method of claim 7, wherein the positional relationship is a euclidean distance between the pixel point and a reference point, and the obtaining the compensation data corresponding to the compensation index comprises:
and calculating compensation data corresponding to the compensation index according to a preset compensation curve.
9. The method of claim 7, wherein calculating a positional relationship between the pixel point and a reference point based on the position of the pixel point, to obtain a compensation index, comprises:
calculating the difference value between the abscissa of the pixel point and the abscissa of the reference point to obtain a line difference; calculating the difference between the ordinate of the pixel point and the ordinate of the reference point to obtain a column difference; wherein the row and column differences constitute the compensation index;
the obtaining the compensation data corresponding to the compensation index includes: and acquiring compensation data corresponding to the compensation index from a preset compensation matrix.
10. An intelligent device, comprising:
a cover plate;
the light source is internally arranged in the intelligent equipment and used for emitting light rays to irradiate a target object contacting the cover plate;
the apparatus for acquiring a biometric image according to any one of claims 1 to 6, wherein the apparatus acquires a biometric light signal emitted from the light source and reflected by the target object.
11. A display device, characterized by comprising:
a display panel for emitting light rays to irradiate a target object contacting the display panel;
the apparatus for acquiring a biometric image according to any one of claims 1 to 6, wherein the apparatus acquires a biometric optical signal emitted from the display panel and reflected by the target object.
12. The display device according to claim 11, wherein the display panel is any one of an OLED panel, an LED panel, and an LCD panel.
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| CN112464826A (en) * | 2020-11-30 | 2021-03-09 | 京东方科技集团股份有限公司 | Photosensitive module, fingerprint acquisition system, substrate, driving method and display device |
| CN113365002B (en) * | 2021-06-04 | 2022-09-16 | 深圳市汇春科技股份有限公司 | Fixed mode noise dynamic compensation device and method and terminal equipment |
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