Summary of the invention
The object of the invention provides a kind of based on bionical and examiner identity appraising system living things feature recognition, improvement by method, realization is identified fast, accurately to examiner's identity, both to be applicable to the examiner's identity authentication under the existing paper examination pattern, the machine in the future that is applicable to is again examined the identity authentication under the pattern.
For achieving the above object, the technical solution used in the present invention is: a kind of based on bionical and examiner identity appraising system living things feature recognition, comprise and utilize collector to gather multiple biological characteristic, the data of gathering are handled, authenticated evaluation according to training sample set, specifically may further comprise the steps:
(1) gather examiner's multinomial biological characteristic simultaneously, the data that collect are transferred to communication front-end equipment after by hardware encipher, described biological characteristic comprises on-line signature at least, fingerprint pattern and facial image hold a pen;
(2) collect the pre-service of data, comprise data are carried out filtering and regularization;
(3) from pretreated data, carry out feature extraction and characteristics combination, pass through the data soft encryption again, be transmitted through the network to back-end processing equipment then;
(4) back-end analysis of data is handled: the packet in that the back-end processing device decrypts receives from network, adopt the identification that realizes examiner's identity based on the living things feature recognition method of higher dimensional space geometrical body self-adaptation covering theory;
(5) sample set dynamically updates: the data that checking is passed through are added in the sample set, dynamically generate template corresponding, make new template reflect the trend of sample changed.
In the technique scheme, the acquisition method of described step (1) is, at first gather examiner's on-line signature by database, utilize people's metastable characteristics of attitude when signature to adopt camera to obtain people's face and signature posturography picture comparatively clearly, the fingerprint image that holds a pen of the signature pen collection that is provided with Multifunction Sensor by front end simultaneously, the described fingerprint image that holds a pen behave finger when holding a pen with between whole contact informations, comprise the fingerprint texture segment and the relative position of all contact positions.
Wherein, gather the pressure characteristic that holds a pen simultaneously at signature, its method is, in each contact position of described signature pen pressure transducer is set, gather hold a pen pressure in signature process variation and carry out record corresponding to the respective regions of the fingerprint image that holds a pen.
The synchronous acquisition mode of above-mentioned steps (1) can be called the mode that " one-stop " gathers biological characteristic, it has realized collecting static state as much as possible (people's face, fingerprint) and dynamic (signature) biological information in examiner's once signed writing process, have Noninvasive and accessibility preferably, especially it is everyone peculiar biological characteristic that the pressure that holds a pen in fingerprint image and when signature of holding a pen changes, have monopoly and exclusiveness, and can improve the accuracy rate of identification significantly after other biological characteristic combines.
Because the singularity of biological information, it is particularly outstanding that the data security problem seems.Native system at first carries out Data Format Transform with the data that collect by encryption chip, and then it is transferred to communication front-end equipment, has eliminated the potential safety hazard of data in transmission course.
Step in the technique scheme (2) is carried out pre-service to the data that collect, its fundamental purpose is the irrelevant information in the removal of images, recover useful real information, strengthen for information about detectability and reduced data to greatest extent, thus raising subsequent treatment result's reliability.In native system, mainly used following preprocess method: normalization, level and smooth, restore and strengthen.
Step in the technique scheme (3) comprises feature extraction, the detection of people's face and the feature extraction of on-line signature and the feature extraction of the fingerprint that holds a pen to carrying out feature extraction through pretreated data; Through after the feature extraction phases, how from numerous and complicated various feature, to filter out useful feature, and it is organically blended to form corresponding proper vector be the difficult point of area of pattern recognition always.The technical program is from bionical angle, adopt the thought of multiscale analysis to realize organically blending between the linked character collection, at first the feature after extracting being carried out yardstick divides, it is divided into Global Information and detailed information, and then further divide according to the relevance between feature, the feature that relevance is strong is divided into same linked character collection, carries out Feature Fusion at last, and linked character is synthesized proper vector.
After facial image, on-line signature and the fingerprint image that holds a pen had been carried out feature extraction, communication front-end equipment need be analyzed identification by Network Transmission to back-end processing equipment with merging good proper vector.Proper vector comprises examiner's biological information, and is the significant data source that back-end analysis identification and training sample set upgrade, and its importance is self-evident.The present invention adopts cryptographic algorithm, and a kind of multistep cryptographic algorithm is encrypted data, changes the data layout of proper vector, and the form with packet arrives back-end processing equipment with data by Network Transmission then, has protected examiner's personal information security effectively.
Behind the packet that the back-end processing device decrypts receives from network it is authenticated evaluation, the present invention adopts diverse ways to carry out matching degree for global characteristics vector sum minutia vector and calculates.For the vectorial point that directly its mapping is become in the higher dimensional space of global characteristics, according to the continuity of similar sample point in higher dimensional space, training sample set should be covered by limited, the continuous zone of a slice, treats that by analysis the relation of observation station and training sample set overlay area can obtain the matching degree between this biometric sample and training sample set; Then adopt the method for dynamic programming to carry out template matches for minutia.Obtain a kind of matching degree of biological characteristic after then both result being multiplied each other, the decision making algorithm of employing fusion is at last handled the matching degree between multiple biometric sample and training sample set, obtain the whole matching degree after the matching degree weighted sum with multiple biological characteristic, the identification conclusion can be drawn with threshold ratio after, evaluation can be realized examiner's identity.
The priori that " continuity of similar sample point in higher dimensional space " distributes as sample point, think that certain biological characteristic (signature, fingerprint, the people's face) sample that comes from same individual should be continuous in higher dimensional space, be to undergo mutation between the sample, all there is a continually varying curve between any two sample points, makes one of them sample point carry out the transition to the another one sample point smoothly.Principle that Here it is " homology continuity " that is: is established among the feature space Rn all and is belonged to all of category-A things and be set A, if having any two element x and y in the set A, then for arbitrarily greater than 0 value ε, must have set B, make:
Corresponding to learning process, be exactly the distribution of training sample in feature space at things of the like description, select one or more suitable occluding surfaces, the continuous complicated geometirc physique that forms a higher dimensional space rationally covers training sample.And this complicated geometirc physique need carry out self-adaptation according to the distribution of training sample and chooses, and covers training sample set with reasonable manner.
When the user carries out after authentication passes through, new biometric sample information also automatically by system record.When limited storage space, training sample set must dynamically be deleted some stale informations when adding fresh information, and it is significant allowing training sample set embody its variation tendency in the mode that dynamically updates.
The update mode of training sample set can be by geometrical body in the higher dimensional space the selection of overlay area consider.The present invention has realized that the self-adaptation of overlay area dynamically generates, think that promptly training sample set after dynamically updating should realize the most reasonable dynamic covering to all samples in higher dimensional space, to verify that newly the biological characteristic that passes through is updated to training sample set, simultaneously with stale information filtering from the overlay area.
Because the technique scheme utilization, the present invention compared with prior art has following advantage:
1. on-line signature, people's face, signature posture have been gathered when gathering examiner's biological characteristic, also adopt the signature pen that has Multifunction Sensor, pressure variation when having gathered finger and the contacted whole fingerprints of pen and corresponding holding a pen, abundant biological information has monopoly and exclusiveness, in conjunction with after can improve the accuracy rate of identification significantly.
Data when collecting device is transferred to communication front-end equipment through hardware encryption---encryption chip is encrypted, when communication front-end equipment is transferred to back-end processing equipment through soft encryption---the multistep cryptographic algorithm is encrypted, and has guaranteed the safety of data.
3. total system has incorporated bionical thought, and the mode in the cognitive world of imitation people is carried out pattern-recognition, and its core concept is embodied in following three aspects:
(1) people's thinking can be divided into two kinds of logical thinking and thinkings in images, and it is based on the reasoning from logic process development by deduction that brain carries out logical thinking, carries out thinking in images and then be developing based on the summary of experience process of method of induction.Pattern-recognition is a kind of thinking in images problem more, and the variable quantity that it relates to is often a lot, and it is carried out strict reasoning from logic, and it is unpractical adopting the multi-variable function Modeling Calculation.Therefore, solve the describing mode that pattern recognition problem must find a kind of thinking in images, and the figure notion, geometrical body was described and just is a kind of effective describing mode of thinking in images during promptly the higher-dimension sky was asked.
(2) people has the dimensional variation notion when discerning.With signature, people's face and fingerprint is example, and the people not only observes its overall profile when identification, and pays close attention to its minutia.Therefore, when extracting signature, people's face and fingerprint characteristic, not only to consider global informations such as length breadth ratio, form, and will pay close attention to detailed information such as stroke intersection, canthus lines, identifying object be estimated exactly from different yardsticks.
(3) people brings in constant renewal in as the data base of identification.After the people has discerned certain object according to priori, the existing feature information of refining into of this object can be stored memory, so that accurate identification in the future.Therefore, sample to be tested and existing training sample set are compared and determine that it is true after, the new data that checking is passed through need be added in this sample set automatically, and again it is assessed, according to the distribution situation of each sample in higher dimensional space, reasonably remove outmoded sample, make new training sample set reflect the variation tendency of identifying object.
4. system of the present invention is from bionical thought, integrated use realizes evaluation to examiner's identity based on the various living things feature recognition methods of higher dimensional space geometrical body self-adaptation covering theory, identify quick, the result is accurate, be not only applicable to the examiner's identity authentication under the existing paper examination pattern, and examine at machine in the future and to have more wide application prospect under the pattern.
Embodiment
Below in conjunction with drawings and Examples the present invention is further described:
Embodiment one:, a kind of referring to accompanying drawing 1 based on bionical and examiner identity appraising system living things feature recognition to shown in the accompanying drawing 4, elaborate by following steps:
The first step, the collection of on-line signature, hold a pen fingerprint pattern and facial image data.
Adopt the mode shown in the accompanying drawing 1, utilize database collection examiner's on-line signature, utilize the camera collection facial image simultaneously and the fingerprint image that holds a pen, and the Multifunction Sensor collection by the dedicated signatures anterior end of pen hold a pen fingerprint image and the pressure information that holds a pen when writing, this sensor not only can be gathered the hold a pen fingerprint image of people when signing, and the pressure that holds a pen in can the perception signature process changes, the described fingerprint image that holds a pen is different from the single piece of complete finger print image that the conventional fingerprint collecting device collects, it write down when the people holds a pen finger with between whole contact informations, comprise the fingerprint texture segment and the relative position of all contact positions; Simultaneously, the variation of the pressure of each contact position in signature process is also by sensor acquisition and corresponding to the respective regions of the fingerprint image that holds a pen.
Subsequently, native system carries out Data Format Transform with the data that collect by special encryption chip, again it is transferred to communication front-end equipment, has guaranteed the data security of user biological characteristic information effectively.
In second step, the data that collect are carried out pre-service.
Pretreated fundamental purpose is the irrelevant information in the removal of images, recovers useful real information, strengthens for information about detectability and reduced data to greatest extent, thus raising subsequent treatment result's reliability.In native system, mainly used following preprocess method:
(1) normalization
Make some feature of image under given conversion, have a kind of graphics standard form of invariance.Some character of image, for example the area of object and girth just had constant character originally for rotation of coordinate.In the ordinary course of things, the influence of some factor or some character of transfer pair image can be eliminated or weakens by normalized, thereby can be selected as the foundation of measurement image.Gray scale normalization, geometrical normalization and transform normalization are three kinds of method for normalizing that obtain the image invariance.
(2) level and smooth
The technology of random noise in the removal of images.To the basic demand of smoothing technique is that in the cancellation noise image outline or lines to be thickened unclear.Smoothing method commonly used has median method, part to ask the method for average and the k neighbour method of average.The regional area size can be fixed, and also can be that pointwise is with the gray-scale value size variation.In addition, application space frequency field band-pass filtering method sometimes.
(3) restore
Proofread and correct the image degradation that a variety of causes caused, make reconstruction or estimate that the image that obtains approaches the desirable image field of degenerating that do not have as much as possible.Usually the image degradation phenomenon can take place in actual applications, the aberration of optical system for example, the relative motion of camera and object all can make facial image degenerate.Basic recovery technique is that (x, (x is y) with ideal image f (x, convolution y) y) to regard degenrate function h as the degraded image g that obtains.Their Fourier transform exist concern G (u, v)=H (u, v) F (u, v).After determining degenrate function according to degradation mechanism, just from then on relational expression obtain F (u, v), again with Fourier inversion obtain f (x, y).Usually M (u, v)=(u v) is called inverse filter to 1/H.During practical application, (u v) increases with the distance of leaving uv plane initial point and descends rapidly, and u is worked as in the reinforcement of noise in the high-frequency range because H
2+ v
2During greater than a certain boundary value W0, (u v) equals 1 to make M.The selection of W0 should make H, and (u is v) at u
2+ v
2In≤W0 the scope zero point can not appear.The algebraic method of image restoration is based on the least square method optimum criterion.Seek an estimated value, make goodness criterion function value minimum.This method is fairly simple, can derive the least square method S filter.When not having noise, S filter becomes desirable inverse filter.
(4) strengthen
Information in the image is strengthened selectively and suppressed, improving the visual effect of image, or change image into be more suitable for form, so that data pick-up or identification in machine processing.For example an Image Intensified System can be given prominence to the outline line of image by Hi-pass filter, thereby makes shape and girth that machine can the measuring wheel profile.Image enhancement technique has several different methods, and contrast broadening, log-transformation, density stratification and histogram equalization etc. all can be used for changing image tone and outstanding details.Often to use diverse ways during practical application, test repeatedly just and can reach satisfied effect
The 3rd step, pretreated data are carried out feature extraction, and be combined into proper vector, behind the data soft encryption, arrive back-end processing equipment then by Network Transmission.
(1) feature extraction of on-line signature
Comprised abundant characteristic information in the on-line signature, on time-spatial information (si) (as accompanying drawing 3) and transform domain information division can be with the following table sorts of various features.
In addition, some global characteristics in the on-line signature also merit attention, and pen is gone up line time and accounted for ratio of T.T. or the like in the length breadth ratio of the deadline of for example signing, signature image, the signature process.
For time dependent features such as speed, inclination angle, pressure, the present invention at first is merged into it proper vector, and then is arranged in the proper vector chain, adopts the method for dynamic programming to carry out template matches; And for global characteristics, the present invention is arranged in the observation station for the treatment of that is mapped to after the proper vector in the higher dimensional space with it, utilizes the relation for the treatment of in the higher dimensional space between observation station and the sample overlay area to determine its matching degree.
(2) people's face detects and feature extraction
The present invention is based on complexion model, directly adopt YCbCr color space and passing threshold that area of skin color is adjudicated, to each point in the image (x, y), we with f (x, y) represent that whether this point belongs to skin pixel, obtains following formula:
Adopt particle swarm optimization algorithm that area of skin color is cut apart then.Particle swarm optimization algorithm is based on the evolution algorithmic of colony, and its thought source is in artificial life and EVOLUTIONARY COMPUTATION theory.During PSO solving-optimizing problem, problem separate corresponding to one " particle " in the search volume (particle) or " main body " (agent).Each particle all has position and the speed (direction of decision flight and distance) of oneself, also has an adaptive value by optimised function decision.Each particle is remembered, is followed current optimal particle, searches in solution space.The process of each iteration is not a completely random, if find better solutions, will seek the next one on this basis and separate.
Make PSO be initialized as a group random particles (RANDOM SOLUTION), in iteration each time, particle upgrades oneself by following the tracks of two " extreme values ": first is exactly preferably separating of being found of particle itself, be called extreme point (representing its position) with pbest, another extreme point among the PSO is preferably separating of finding at present of whole population, is called global extremum point (representing its position with gbest).
After finding two optimal values, particle upgrades speed and the position of oneself by following formula.
V
i=ω×V
i+c
1×rand()×(pbest
i-x
i)+c
2×rand()×(gbest
i-x
i) (2)
x
i=x
i+V
i (3)
In above-mentioned two formulas:
I=1,2 ..., M, M are the sums of particle in this colony;
V
iIt is particle's velocity;
Rand () is the random number between (0,1);
x
iIt is the current location of particle;
c
1And c
2It is the study factor;
ω is non-negative, is called inertial factor.
In each dimension, particle all has a maximum constraints speed V
MaxIf the speed of certain one dimension surpasses the V that sets
Max, the speed of this one dimension just is restricted to V so
Max(V
Max>0).
(2) in the formula, the ω value is bigger, and then global optimizing ability is strong, a little less than the local optimal searching ability; Otherwise the ω value is less.When initial, ω is taken as constant, and experiment afterwards finds that dynamically ω can obtain than the better optimizing result of fixed value.Dynamically ω can change at PSO search procedure neutral line, also can dynamically change according to certain measure function of PSO performance.What the present invention adopted is linear decrease weights strategies.
ω
(t)=(ω
ini-ω
end)(G
k-g)/G
k+ω
end (4)
G
kBe maximum evolutionary generation, ω
IniBe initial inertia weights, ω
EndBe iteration inertia weights when the maximum algebraically.
After area of skin color was determined, the zone of being cut apart might comprise some non-face zones, therefore needed to adopt fuzzy membership function that people's face is differentiated.Fuzzy membership functions is defined as follows:
Native system is explained people's face with 3 features.Be respectively the height of people's face, ratio and people's face vertical offset angle of height and the width, adopt fuzzy membership functions these parameter fuzzy to be divided the fuzzy membership functions μ that does not obtain three features
1(x), μ
2(x) and μ
3(x), whether be total subordinate function of people's face with its product as this zone of differentiation, that is:
μ(x)=μ
1(x)·μ
2(x)·μ
3(x) (6)
If the membership function value in a certain zone, thinks then that this zone is exactly a human face region greater than a certain threshold value, use for the single face of native system, then the zone of membership function value maximum is a human face region.
Need to extract face characteristic after detecting human face region, face characteristic mainly comprises the variation of position, size and the shape of eyes, eyebrow, face.At first utilize principal component analysis to combine with the human face ratio characteristic, after obtaining the preliminary region of eyes, use technology such as rim detection, can determine the accurate position of pupil rapidly and accurately, utilize the color characteristic of the ratio feature of people's face and eyebrow, face then, can extract eyebrow and face very accurately.The identification of people's face will be can be used for after remarkable characteristic in these facial characteristics or the attributes extraction.
(3) the hold a pen feature extraction of fingerprint
As shown in Figure 2, the fingerprint that holds a pen that is collected among the present invention is different from single piece of traditional complete finger print, the finger that is the user when signature of its record with between whole contact informations, comprise the fingerprint texture segment and the relative position of all contact positions.Therefore, classic method and new method have been merged in its characteristic extraction procedure.
Fingerprint generally has two kinds of structures: Henry fingerprint pattern and Galton feature.The Henry classification is that standard designs qualitatively, characterizes the one-piece construction of crest pattern, is generally used for dividing finger print data.The Galton General Definition four characteristics: the starting point and the terminal point of (1) crest; (2) branch; (3) isolated area; (4) disturb.In order from the digital finger-print image, to extract feature, at first selected to comprise eight features of four Galton characteristics, and it has been divided into two classes: original and synthetic.Primitive character is respectively a little, crest terminal point and branch.On this basis, defined composite character again: isolated zone, burr intersects, bridge and short peak.In addition, fingerprint image can also extract following feature for holding a pen: fingerprint number of slices, relative position etc. between each segment.
(4) proper vector is synthetic
Through after the feature extraction phases, how from numerous and complicated various feature, to filter out useful feature, and it is organically blended to form corresponding proper vector be the difficult point of area of pattern recognition always.The present invention adopts the thought of multiscale analysis to realize organically blending between the linked character collection from bionical angle.
At first, each feature is carried out yardstick divide, it is divided into Global Information and detailed information.And then further divide according to the relevance between feature, pressure information, the writing speed of signature and the variation at stroke direction angle of writing down on the dynamics variation of the center of effort that holds a pen during such as signature, the numerical digit plate have stronger correlativity, can be divided into same linked character collection.Carry out Feature Fusion at last, linked character is synthesized proper vector.
Discussion with the front is an example, makes d
i(i is a center of effort quantity) expression dynamics that holds a pen, p represents that the pressure that writes down on the numerical digit plate, v represents the writing speed of signing, θ represents deflection, then can obtain a linked character vector φ (d
i, p, v, θ).
(5) data soft encryption and Network Transmission
Because the singularity of biological information, it is particularly outstanding that the data security problem seems.Consider the information security issue in the Network Transmission, native system has adopted a kind of multistep cryptographic algorithm that the transmission data are encrypted.
This algorithm uses a series of numeral (such as 128 keys), produces one repeatably but the pseudorandom Serial No. of height randomization.Once use 256 list items, use random number sequence to produce password commentaries on classics table, promptly 256 random numbers are placed in the matrix, then it is sorted, produce an arbitrarily table of ordering according to initial position, the numeral in the table is between 0 to 255.Produced the table of 256 concrete bytes like this.Allow this tandom number generator follow to produce remaining number in this table, to such an extent as to each table is different.Next, use " Shot Gun Technique " technology to produce decoding table.Basically, if a is mapped to b, b necessarily can be mapped to a so, so b[a[n]]=n (n is a number between 0 to 255).Assignment in a circulation makes the black list of the decoding table of one 256 byte corresponding to 256 bytes that produce previously.
By this method, can produce a such table, the order of table is at random, so what produce that the random number of these 256 bytes uses is the secondary pseudorandom, has used two 16 extra passwords.Now, two conversion tables have been arranged, basic encrypting and decrypting process is as described below: previous byte ciphertext is the index of the table of this 256 byte, perhaps, in order to improve cipher round results, can use unnecessary 8 value, even use verification and or the crc algorithm produce the index byte.Suppose that this table is 256 * 256 array, it satisfies so:
encrypt1=a[encrypt0][value]
Variable ' encrypt1 ' is a data encrypted, and ' encrypt0 ' is previous enciphered data (or functional value of the several enciphered datas in front).Very natural, first data need one " seed ", and this " seed " must be remembered.
The pseudo-random sequence that is produced during encryption is very random, any sequence that can be designed to want.About the detailed information of this random series, decrypting ciphertext is not unpractical.For example: the sequence of some ASCII character, may be converted to some mess codes at random as " processing " without any meaning, each byte all depends on the ciphertext of its previous byte, rather than actual value.For this conversion of any single character, hidden the effective real length of enciphered data.
In the 4th step, adopt based on the living things feature recognition method of bionical and higher dimensional space geometrical body self-adaptation covering theory and identify examiner's identity.
The present invention adopts diverse ways to carry out matching degree for global characteristics vector sum minutia vector and calculates.Directly its mapping is become point in the higher dimensional space for global characteristics vector, calculate the matching degree between itself and training sample set; Then adopt the method for dynamic programming to carry out template matches for minutia.Obtain a kind of matching degree of biological characteristic after then both result being multiplied each other, obtain the whole matching degree after the matching degree weighted sum with multiple biological characteristic at last, can draw the identification conclusion after with threshold ratio.
Be identified as example with on-line signature, at first the vector of each linked character in the minutia adopted the method for dynamic programming to solve the matching degree of itself and training sample set, the matching degree weighted sum that obtains is obtained the minutia matching degree.Then the global characteristics DUAL PROBLEMS OF VECTOR MAPPING is become a point in the higher dimensional space, obtain corresponding global characteristics matching degree according to the relation of itself and training sample set overlay area.At last details and global characteristics matching degree are multiplied each other and obtain final on-line signature whole matching degree.At last with after the matching degree weighted sum of on-line signature, people's face, the fingerprint that holds a pen with threshold ratio, finally realize the checking of examiner's identity.
In the 5th step, dynamically update training sample set.
When the user carries out after authentication passes through, new biometric sample information also automatically by system record.When limited storage space, training sample set must dynamically be deleted some stale informations when adding fresh information.This is reasonably in actual applications, so people's signature custom may be along with the time changes, and it is significant allowing training sample set embody its variation tendency in the mode that dynamically updates.
The update mode of training sample set can be by geometrical body in the higher dimensional space the selection of overlay area consider.The present invention has realized that the self-adaptation of overlay area dynamically generates, think that promptly training sample set after dynamically updating should realize the most reasonable dynamic covering to all samples in higher dimensional space, to verify that newly the biological characteristic that passes through is updated to training sample set, simultaneously with stale information filtering from the overlay area.