CN105991997B - A kind of method that condenser type imaging sensor bad point positions in real time - Google Patents
A kind of method that condenser type imaging sensor bad point positions in real time Download PDFInfo
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- CN105991997B CN105991997B CN201510100617.5A CN201510100617A CN105991997B CN 105991997 B CN105991997 B CN 105991997B CN 201510100617 A CN201510100617 A CN 201510100617A CN 105991997 B CN105991997 B CN 105991997B
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Abstract
The present invention relates to a kind of method that condenser type imaging sensor bad point positions in real time, comprise the following steps：Step 1, capacitor array parameter (each capacitance point parameter is consistent) is adjusted, starts sensor and gathers a secondary background image, and generate histogram；Step 2, the section according to where the pixel of histogram search more than 80%, and record the starting gray value in the section and terminate gray value；Step 3, gathered with first time under identical parameters, start sensor and gather a width background image again, and whether real-time judge image intensity value is distributed between starting point and end point to determine whether the point is bad point；After the completion of judging a little, by reading marking signal, the position of bad point is determined.The real-time positioning mode of condenser type imaging sensor bad point proposed by the present invention is realized simple, shared resource is few, detection and localization can be carried out to bad point when dispatching from the factory, while can detected in real time due to bad point caused by the factors such as use environment in the application, and repair process is carried out to bad point.
Description
Technical field
The invention belongs to technical field of image processing, and in particular to what a kind of condenser type imaging sensor bad point positioned in real time
Method.
Background technology
Due to production technology deviation and yield issues, cause condenser type imaging sensor when dispatching from the factory, sensor electricity
Hold the abnormal electric capacity that array point has random distribution, it is bad point that now we, which define the abnormal capacitance point,.Bad point is more than a fixed number
Amount, can have a strong impact on picture quality, cause image useless.Simultaneously as the capacitor array silicon of condenser type imaging sensor is not
All silicon materials can be covered as traditional die packing forms so that the exposure for a long time of electric capacity collection array in atmosphere, is held very much
Capacitor cell damage is easily caused, most has influence on picture quality at last.Qualified sensor in use, because various situations are easy
The damage of array point is caused to occur often.
As introduced above to understand, product yield and sensor image quality are directly related with bad point number.How bad point is positioned
Position, while it is present focus on research direction to repair bad point, the condenser type imaging sensor for thereby producing present patent application is bad
Point location algorithm and image repair algorithm.
The method that current existing CCD, CMOS camera, capacitance plate and the capacitive fingerprint sensing device of foreign countries detect bad point
All it is the image that different gray values are sent into by certain mode, bad point and bad point is judged whether according to variation of image grayscale
Position positions.Domestic bad point detection and reparation at present, it is substantially main for capacitance plate, video camera, domestic detection method
By the image for being manually fed into different gray values；And external capacitance type sensor bad point detection, by sensor array list
The mode of finishing coat electrolyte solution (or electrolyte) changes the background gray scale that sensor collects, and is judged according to gray-value variation
With the presence or absence of bad point.Existing implementation complex procedures both at home and abroad are high and existing to electrolyte material and coating required precision
Mode is not easy batch, carries out bad point detection and positioning in real time.
The content of the invention
In order to solve the problems, such as that prior art is present, the present invention proposes fixed in real time for condenser type imaging sensor bad point
The method of position, realizability condition is provided for bad point reparation, and the implementation is realized relative to conventional dead pixel detection method
Simply, it is easy to batch detection and in real time detection.
The principle of bad point detection, which comes from, to be analyzed capacitance type sensor image-forming principle, according to image-forming principle when designing circuit
Addition testing capacitor (if each array point can change sensor background image intensity value by adjusting other parameters in itself, should
Testing capacitor device can be without access).The testing capacitor is mainly used in changing the gray value of sensor background image.Sensor array
Each capacitor cell circuit structure on row is identical, theoretical performance and function should as, due to the production error of chip,
Under identical parameters, when gathering background image, image intensity value is distributed in theoretical value small range nearby, and the tonal range is in normal state point
Cloth, the point not within the scope of normal distribution are labeled as bad point.
The method that the condenser type imaging sensor bad point of the present invention positions in real time, mainly comprises the following steps：
1, adjustment capacitor array parameter (each capacitance point parameter is consistent), the parameter make it that the gray value of background image is main
Intermediate grade of the integrated distribution in sensor tonal range；Start sensor and gather a width background image, and count the Background
The histogram of picture；The capacitor array includes reference capacitance, reference voltage and testing capacitor；The testing capacitor, is mainly used in
Change the gray value of sensor background image；
2, according to the normal distribution characteristic of image intensity value, more than 80% pixel institute is searched on histogram distribution curve
Normal distribution section, and record the section starting gray value and terminate gray value；
3, set with collection identical parameters for the first time, starting sensor and gathering a width background image again, and sentence in real time
Break each capacitance point corresponding grey scale value whether in normal distribution section, if not within the range, labeled as bad point；It is all
After the completion of point judges, by reading marking signal, the position of bad point is determined.
This patent is described in detail by taking capacitive fingerprint sensing device as an example.Capacitance type sensor is by multiple capacitor cells
The condenser type collection array of composition is formed.The capacitance difference of fingerprint ridge, paddy is converted into by each capacitor cell by electric capacity electric discharge
Voltage signal or current signal, and it is sent into ratio according to regular hour cycle T sample voltage value or current value, and by the value
Analog quantity is converted into digital 2 values (0/1) signal compared with device, the value signal bound-time point of numeral 2 is the gray value of the point.
When carrying out bad point detection, finger electric capacity is not accessed, the gray value for influenceing capacitor cell generation mainly has with reference to electricity
Appearance, reference voltage and testing capacitor, the circuit structure of each capacitor cell and the parameter value of influence background imaging are the same, theoretical
The background gray levels of upper all array points should be the same.But due to the little deviation of technique productions, all normal array point ashes
Angle value should be distributed in the gray scale interval of a small range, i.e. normal distribution section, and the array point not in the gray scale interval is determined
Justice is bad point.
According to above-mentioned principle, the present invention carries out bad point detection judgement according to following steps：
(1) reference capacitance, reference voltage and testing capacitor are adjusted, it is gray image (i.e. background to make sensor background image
The main integrated distribution of gray value is in the intermediate region of sensor tonal gradation).Start sensor and gather a width background image, and it is raw
Into histogram information corresponding to the image.
(2) distributed area according to where histogram information searches for more than 80% pixel, the section is in normal distribution shape
Formula, and obtain the starting tonal gradation start in the section and terminate tonal gradation end.
(3) in the case where gathering background image identical parameters with first time, gather Background again, and according to condition start≤
Whether image (m, n)≤end, gray value corresponding to each capacitor cell of real-time judge are distributed in normal distribution section.Such as
Really bar part meets that capacitor cell corresponding to image (m, n) is normal point, is otherwise bad point, and mark the electricity using 1bit signals
Hold location mode (normal point or bad point).Wherein, image (m, n) is m rows, the gray value corresponding to the n-th column capacitance unit.
(4) by reading all marking signals, you can determine bad point position, subsequently carry out bad point according to bad point position
Repair process.
The invention provides a kind of method that condenser type imaging sensor bad point positions in real time, its advantage are as follows：
(1) method that condenser type imaging sensor bad point proposed by the present invention positions in real time realizes simple, shared resource
It is few, it is easy to batch detection and in real time detection.The bad point detection can carry out detection and localization when dispatching from the factory to bad point, while answer
It can be detected in real time by this method in due to carrying out repair process using bad points caused by factor such as bad borders, and to bad point.
(2) method that condenser type imaging sensor bad point proposed by the present invention positions in real time be applied to capacitance type sensor,
Inductance type transducer, resistance sensor etc. and capacitive fingerprint sensing device belong to each imaging unit circuit structure it is identical and
Image-forming principle identical imaging sensor.If other similar sensors, it need to only change the subtest device in circuit design
Part (testing capacitor), you can realize that bad point positions by above-mentioned same method.
Brief description of the drawings
Fig. 1 is a kind of flow chart of condenser type imaging sensor bad point real-time location method embodiment of the present invention；
Fig. 2 is a kind of capacitance type sensor list of condenser type imaging sensor bad point real-time location method embodiment of the present invention
The circuit structure of individual capacitor cell；
Fig. 3 is a kind of background image histogram of condenser type imaging sensor bad point real-time location method embodiment of the present invention
Distribution schematic diagram.
Embodiment
Illustrate the preferred embodiments of the present invention below in conjunction with the accompanying drawings, specific embodiment described herein is only solving
The present invention is released, is not intended to limit the present invention.
This patent is described in detail by taking capacitive fingerprint sensing device as an example.Fig. 2 describes the electricity of one embodiment of the invention
The circuit structure of the single capacitor cell of capacity sensor.Each capacitor cell puts the capacitance difference of fingerprint ridge, paddy by electric capacity
Electricity is converted into voltage signal or current signal, and according to regular hour cycle T sample voltage value or current value, and should
Value is sent into comparator (250) and analog quantity is converted into digital 2 values (0/1) signal, and the value signal bound-time point of numeral 2 is should
The gray value of point.
When carrying out bad point detection, finger electric capacity C is not accessedfinger(210) the gray value master of capacitor cell generation, is influenceed
There is reference capacitance Cref(230), reference voltage VrefAnd testing capacitor C (240)test(220), the circuit knot of each capacitor cell
Structure and the parameter C for influenceing background imagingref(230)、Vref(240)、Ctest(220) value is the same, in theory all array points
Background gray levels should be the same.Due to the little deviation of technique productions, all normal array point gray values should be distributed in one
The gray scale interval of individual small range, i.e. normal distribution section, the array point not in the gray scale interval are defined as bad point.
Reference picture 1, a kind of flow chart of condenser type imaging sensor bad point real-time location method embodiment of the present invention is shown,
Including：
Step 110, C is adjustedref(230)、Vref(240)、Ctest(220) it is gray image, to make sensor background image, i.e.,
Intermediate grade of the main integrated distribution of gray value of background image in sensor tonal range；
Step 120, start sensor and gather a width background image, and histogram information corresponding to generating the image, be designated as
Hist, the number of pixels that gray value is i, the background image histogram distribution schematic diagram of the embodiment of the present invention are represented with hist (i)
As shown in figure 3, wherein abscissa i is tonal gradation；
Step 130, the distributed area according to where histogram information searches for more than 80% pixel, the section is in normal state point
Cloth form, as shown in normal distribution section (330) in Fig. 3, and obtain the starting tonal gradation start (350) and knot in the section
Beam tonal gradation end (360).What it is not within the normal distribution section is bad point a little, and the bad point of the present embodiment is in Nogata
Distribution is as shown in 310,320, the 340 of Fig. 3 on figure；
Step 140, in the case where gathering background image identical parameters with first time, Background is gathered again；
Step 150, according to condition start≤image (m, n)≤end, ash corresponding to each capacitor cell of real-time judge
Whether angle value is distributed in normal distribution section, if image (m, n)<Start or image (m, n)>End, then image (m,
N) capacitor cell corresponding to is bad point, is otherwise normal capacitor cell, and mark the capacitor cell state using 1bit signals
(normal point or bad point).Wherein, image (m, n) is m rows, the gray value corresponding to the n-th column capacitance unit.
By reading all marking signals, you can determine bad point position, subsequently carrying out bad point according to bad point position repaiies
Multiple processing.This programme is replaced using the average value of two pixels of two, left side pixel and the right of bad point unit to bad point
Change processing.If image (m, n) is bad point, then image (m, n)=[image (m-2, n)+image (m-1, n)+image (m+ are made
1,n)+image(m+2,n)]/4。
The detailed description and the accompanying drawings of the embodiment of the present invention are only intended to the explanation present invention, rather than limitation by claim and
The scope of the present invention that its equivalent defines.
Claims (5)
1. a kind of method that condenser type imaging sensor bad point positions in real time, it is characterised in that including：
Step 1, capacitor array parameter is adjusted, each capacitance point parameter is consistent, and the parameter make it that the gray value of background image is main
Intermediate grade of the integrated distribution in sensor tonal range；Start sensor and gather a width background image, and count the Background
The histogram of picture；The capacitor array parameter includes reference capacitance, reference voltage and testing capacitor；The testing capacitor, mainly
For changing the gray value of sensor background image；
Step 2, according to the normal distribution characteristic of image intensity value, more than 80% pixel institute is searched on histogram distribution curve
In normal distribution section, and record the starting gray value in the section and terminate gray value；
Step 3, set with collection identical parameters for the first time, starting sensor and gathering a width background image again, and sentence in real time
Break each capacitance point corresponding grey scale value whether in normal distribution section, if not within the range, labeled as bad point；It is all
After the completion of point judges, by reading marking signal, the position of bad point is determined；
The background image refers to the acquired image in no access finger electric capacity.
2. the method that condenser type imaging sensor bad point as claimed in claim 1 positions in real time, it is characterised in that the normal state
Distributed area is the range intervals of regular array point gray value, is the distributed area where more than 80% pixel；The section is in
Normal distribution form, the starting tonal gradation in the section are designated as start, terminate tonal gradation and are designated as end.
3. the method that condenser type imaging sensor bad point as claimed in claim 1 positions in real time, it is characterised in that the judgement
The condition of bad point is：Capacitance point corresponding grey scale value is not in normal distribution section, i.e. image (m, n)<Start, or image (m,
n)>end；
It is described judge normal point condition be：Capacitance point corresponding grey scale value in normal distribution section, i.e. start≤image (m,
n)≤end；
The image (m, n) is m rows, the gray value corresponding to the n-th column capacitance unit.
4. the method that condenser type imaging sensor bad point as claimed in claim 1 positions in real time, it is characterised in that the electric capacity
The method that formula imaging sensor bad point positions in real time applies also for belonging to each imaging unit electricity with capacitive fingerprint sensing device
Line structure is identical and image-forming principle identical imaging sensor.
5. the method that condenser type imaging sensor bad point as claimed in claim 4 positions in real time, it is characterised in that the electric capacity
The method that formula imaging sensor bad point positions in real time applies also for inductance type transducer, resistance sensor.
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| CN201510100617.5A CN105991997B (en) | 2015-03-06 | 2015-03-06 | A kind of method that condenser type imaging sensor bad point positions in real time |
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| CN201510100617.5A CN105991997B (en) | 2015-03-06 | 2015-03-06 | A kind of method that condenser type imaging sensor bad point positions in real time |
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| WO2019041243A1 (en) * | 2017-08-31 | 2019-03-07 | 华为技术有限公司 | Method for verifying function of fingerprint sensor and terminal |
| CN107644220B (en) * | 2017-09-30 | 2021-03-05 | 上海摩软通讯技术有限公司 | Fingerprint identification method and system of mobile terminal |
| CN107729884A (en) * | 2017-11-22 | 2018-02-23 | 广东欧珀移动通信有限公司 | Fingerprint identification method, mobile terminal and computer-readable recording medium |
| WO2019196009A1 (en) * | 2018-04-10 | 2019-10-17 | 深圳市大疆创新科技有限公司 | Method for detecting defective pixel of image sensor, and photography apparatus, unmanned aerial vehicle and storage medium |
| CN110458827B (en) * | 2019-08-12 | 2023-04-07 | 深圳蓝影医学科技股份有限公司 | Method, device, equipment and medium for detecting medical image dead pixels |
| CN113411567B (en) * | 2021-06-02 | 2022-09-23 | 西北核技术研究所 | Array type image sensor laser damage threshold estimation method |
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| CN101212703B (en) * | 2006-12-29 | 2010-05-19 | 华晶科技股份有限公司 | Real-time bad image pixel detection method |
| CN102625133B (en) * | 2011-01-31 | 2014-11-05 | 英属开曼群岛商恒景科技股份有限公司 | Detection method of image sensing of bad pixel |
| TWI456991B (en) * | 2011-12-02 | 2014-10-11 | Ind Tech Res Inst | Method for detecting dead pixels and computer program product thereof |
| TW201419853A (en) * | 2012-11-09 | 2014-05-16 | Ind Tech Res Inst | Image processor and image dead pixel detection method thereof |
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