Design of digital signature verification algorithm using relative slope method

IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 08 | Aug-2014, Available @ http://www.ijret.org 384
DESIGN OF DIGITAL SIGNATURE VERIFICATION ALGORITHM
USING RELATIVE SLOPE METHOD
P.N .Ganorkar1
, Kalyani Pendke2
1
Mtech, 4th
Sem, Rajiv Gandhi College of Engineering and Research, R.T.M.N.U Nagpur (Maharashtra), India
2
Lecturer, Rajiv Gandhi College of Engineering and Research, R.T.M.N.U Nagpur (Maharashtra), India
Abstract
In the era of growing technology, security is the major concern to avoid fakes and forgeries. There are various biometric
technique which help in personal identification, among those verification systems, one system is Signature Verification System,
Signature is a behavioral biometric.It is not based on figure print ,retina or any facial expression, according to the data available
in the input, signature verification split into two part: Online and Offline. It also referred as static and dynamic. Signature
verification also used to provide authentication to user. The main advantages of signature verification are that it used for e-
business which helps in banking applications. The proposed paper present slope based method to identify the signature using
various parameters like speed, time, pressure, movement of signature, accuracy and matching percentage of two signature etc.
Keywords: Segmentation, Hidden Marko Method, Support Vector Machine. Relative slope algorithm, signature
verification, Gaussian elimination algorithm,
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1. INTRODUCTION
Human usually recognize each other by various ways like
their voice when we speak them, by their eyes when we
meet them. To achieve more reliable information for
verification and identification we should use something that
really recognize given person signature verification is one in
that .Signature verification techniques utilize many different
characteristics of an individual’s signature in order to
identify that individual. The advantages of using such an
authentication techniques are signatures are widely accepted
by society as a form of identification and verification.
Information required is not sensitive. [2] So, signature
verification is a very popular area for research now days.
Forging of one’s signature does not mean a long-life loss of
that one’s identity .The basic idea is to investigate a
signature verification technique which is not costly to
develop, is reliable even if the individual is under different
emotions, user friendly in terms of configuration. In
signature verification application, the signatures are
processed to extract features that are used for verification.
[1]There are two stages called enrolment and verification.
Two types of signature verification are offline and online
also called static and dynamic signature based on data
available in the input.
Offline signature (static): The input of offline signature
verification is the image of signature and is useful in
automatic verification signature found on bank check and
account.
Online (Dynamic): Signatures that are captured by data
acquisition devices like pressure-sensitive tablets and
webcam that extract dynamic features of a signature in
addition to its shape (static), and can be used in real time
applications like credit card transactions, protection of small
personal devices (e.g. PDA), authorization of computer
users for accessing sensitive data or programs, and
authentication of individuals for access to physical devices
or buildings. In the point of view of adaption in the market
place, signature verification presents three likely advantages
over other biometrics techniques. First nowadays it is a
socially accepted method already in use in banks and credit
card transaction. Second, it is useful for most of the new
generation of portable computers and personal digital
assistants (PDAs) use and writing as the main input channel.
Third, a signature may be changed by the user. Similarly to
a password while it is not possible to change finger prints
iris or retina patterns.
In this paper, section 2 present literature reviews of the
project .section 3 present proposed systems, proposed
architecture of the project. Section 4 represent methodology,
algorithm used, section 5 represent result/analysis of the
project ,section 6 represent conclusion and section 7 present
references for the project.
2. LITERATURE REVIEW
S.Srihari. K. M. Kalera. And A. XU [1], proposed a
system which represent Hidden Markov model is one of the
widely used models for sequence analysis in signature
verification techniques. Using optimized HMM we can
calculate the segment of the signature. It also gives less error
rate than other (18.4%).
H. S. Sridhar and M. Beall [2], suggested that It extracts
the set of feature representing the signature which provide
different sample from several sample. Second step is for NN
to learn the relationship between signature and its class

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either genuine or forgery.The proposed system highly
suitable for global aspect of handwritten signature.
S.Srihari. K. M. Kalera. And A. XU [3], present a system
the gives idea about proposed method used two techniques
based on template matching. one of them is depend on the
optimal matching and the other based on the elastic
matching. The proposed system tested both the binary and
gray signature every time.
Martinez, L.E., Treviso, C.M, Alonso, J.B., and Ferrer,
M. [4] suggested that the proposed system uses global
directional and grid features of the signature and SVM for
classification and verification. Support vector machine used
various techniques like
Lcss-Global and Lcss-Local Lcss is nothing but local
common subsequence used to find the approximate value of
verified signature.
3. Proposed System
3.1 Proposed Approach
This project proposes a new algorithm for slop calculation
which uses digital pen input signature verification .The
algorithm considers writer’s signature in the form of slopes,
The working of process is like, the slope value of input
signature which is already present in the database and the
slope value of signature taken by the digital pen is match. If
the slope value match up to some approximation (i.e.
approximate value decided by user, like 8o%, 70%), then
the signature will be genuine otherwise forgery. In the
verification phase, the scheme computes a difference
between the slope value of signature which is already store
in database and the current slope value of the pen input.
Care needs to be taken in computing the different function
because the length of the input signature different from that
of the digital signature even if the signature is genuine. If
the computed difference does not exceed a threshold value,
the input signature is predicted to be genuine; otherwise it is
predicted to be forgery. System uses various parameters to
match both the signature. Like, threshold value, time of
signing, speed of signing, pen pressure etc. The system take
various stages to verify signature like data acquisition,
prepossessing, feature extraction, relative slope extraction,
two tier time metric extraction.
3.2 Proposed Architecture
Fig1: General Overview of System
4. METHODOLOGY
4.1 Modules
4.1.1 Database Module
The first database module used to sore and represent all the
slope value in the database form. In this module first system
takes the signature through digital pen and pad .This
signature get store in database with all the values like slope
value ,theta value ,vector in the form of matrix, Eigenvector
etc .System use dataset of vb.net to store the value.
4.1.2 Relative Slope Algorithm
In this module system calculate all the slope value of the
store signature. This module helps to calculate all the
parameters of the signature like pen pressure, threshold
value, time, speed etc of the signature. This algorithm use
optimized HMM method to calculate their values like slope
of line, perpendicular, intersection, centroid of the circle etc.
4.1.3 Comparison Module
This is the last module of the project .this module shows the
comparison between two images or signature done by the
pen in that first is already store signature and second is real

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time signature.The comparison done by various parameter
like pen pressure, location, threshold value, speed and time
of the signature and if the both signature matches upto the
mark or upto particular percentage then signature is genuine
otherwise forgery.
4.2 Relative Slope Algorithm:
The proposed paper present relative slope method to provide
input signature through digital pen to identify a person is
genuine or Forgery based on their handwriting..Current
technology in signature verification uses various algorithm
for future point extraction like genetic algorithm, pattern
matching, Markova method, this project proposed slope
based method which divided a signature into various
segment using optimized HMM method, and slope of every
segment is calculated on based on previous segment and
gives approximate result.
Steps:
1) Preprocess and normalize the algorithm.
2) Divide the signature into segment using optimized HMM
method.
3) Based on requirement combine these segments into line
segment.
4) Calculate the relative slope value of each segment with
respect to previous segment.
5) Carry step (4) till all segment are processed else step (6).
6) Store the slope value of each segment which can be used
for verification.
7) End
Using relative slope algorithm we can minimize the time
and maintenance cost. For this purpose the system is
classified in below
1) Data Acquisition
2) Preprocessing
3) Feature Extraction
4) Relative slope Extraction
5) Tier time metric extraction
6) Signature alignment and enrollment
7) Verification
Fig 2 Here Si: =slope of segment i with respect to previous
segment i-1.
Example: The Fig. Shows the Part of Signature
1) Using optimize HMM we can calculate the segment of
the signature. Then segment can be combining to form a line
segment.
2) After the line segment are obtained the relative slope are
calculated.
3) Slope of line: S=dy/dx
Where: dx=x2-x1 dy= y2-y1
4) For the first segment we calculate the slope between the
starting point of the first segment and the ending point of the
last segment.
5) However, the for the further line segment the slope is
calculated based on the previous line segment
In the first step global time required to put the signature and
calculate.
6) The second step used to calculate the length of signature
completed in unit time for this two tier time metric
extraction algorithm is used.
7) And finally in verification step two level verification
algorithm used in first level of verification relative slope
value compare with previous value
8) And the second level extracts the global and local
features consisting of relative slope value, total length and
global time.
If the signature passes the second level of verification it
considered as genuine signature
4.3 Contribution
Before using the method, the accuracy and some parameters
like threshold value, pen pressure, speed, time of signature
was not up to the mark but after using new this method with
new concept and design method the project gives more
accuracy, threshold value ,pressure all are improved and
gives approximate or satisfied result of the project
5. RESULT/ANALYSIS
Fig 2: Screen Shot Of Original Sign Taken By Pen 1st
Time

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Fig 3: Graph Shows Pressure applied by pen
The above graph shows the pressure when signature taken
by the pen 1st
time.
Fig 4: Graph shows XY movement applied by pen
The above graph shows the XY movement of pen when
signature taken by 1st
time by pen
Fig 5 Graph shows XY movement applied by pen
The above fig. xy movement of pen when signature taken
2nd
by the pen to compare it with 1st
Fig 6.Graph Shows The Pressure Appliied By Pen
The above graph shows the pressure applied by pen when
signature taken by pen 2nd
time for comparision.
Fig 7 Graph shows the comparison between old and new
signature
The above fig..shows the comparison between the two
signature taken by the pen .this graph gives the matching
percentage criteria between two signature and if two
signature matches more than 80% then the signature is valid
or the signature of the person is guanine and if not then
forgery
Fig 8 Messagebox Shows The Matching Criteria Between
Two Signature
The above fig shows the message box which gives the
matching percentage between two signatures. The above
signature matches upto 98% means it is genuine.
6. CONCLUSIONS
The proposed paper presents the method to verify whether
the given signature done by the digital pen is genuine or
forgery. For that, system uses particular method i.e. relative
slope method. Before this project the method gives the result
but there are some parameters like pressure, time, speed,
threshold value and accuracy of the project which gives less
accuracy of the result and after using this project the method

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improves this parameter.the above system increase the
accuracy of the signature above 80% and more,which was
less before this system. The level of accuracy increase with
this project. The disadvantage of biometric can avoided by
this project one can’t sign of another person.
REFERENCES
[1]. S.Srihari.K.M.Kalera.AndA.XU,“Offline Signature
Verification and Identification Using Distance Statistics,
”International Journal of Pattern Recognition And Artificial
Intelligence, vol. 18, no. 7, pp. 1339–1360, 2004.
[2]. H S. Sridhar and M.Beall, “Signature Verifications
Using Kolmogron Smirnov Statistic,”Proceedings of
international Graphonomics Society, Salemo Italy, pp. 152–
156, June, 2005.
[3]. Ashwini Pansare, shalini Bhatia,”Handwritten Signature
Verification using Neural Network,” International Journal of
Applied Information Systems (IJAIS)–ISSN:-2249-0868
Foundation of Computer Science FCS, New York, USA,
January 2012.
[4]. Ramachandra A.C,Jyoti hrinivas Rao”Robust Offline
signature verification based on global features” IEEE
International Advance Computing Conference, 2009.
[5]. Martinez, L.E., Treviso, C.M, Alonso, J.B., and Ferrer,
M. Parameterization of a forgery Handwritten Signature
Verification using SVM.IEEE 38thAnnual 2004
International Carnahan Conference on Security Technology,
2004 PP.193-196
[6]. Christian Gruber, Thyme Gruber, “Online Signature
Verification with Support Vector Machines Based on LCSS
Kernel Functions”, IEEE, August 2010
[7]. Sudarsha Madabashi,Vivek Shriniwas,”Online Offline
signature verification using relative slope algorithm.”
international workshop on measurement system IEEE,
March2005.
[8]. H.Morita, T.Ohishi, Y. Komiya,“On-line Signature
Verification Algorithm Incorporating Pen Position, Pen
Pressure and Pen Inclination Trajectories”, IEEE, 2001.
[9]. Enrique Argones Rua, “Online Signature Verification
Based on Generative Models”, IEEE, August 2012.
[10]. Ming Men, Xizang Xi, Sizing Lou,“On-line Signature
Verification Based on Support Vector Data Description and
Genetic Algorithm”, IEEE, 2008.
[11]. T.S. Enturk. E .O zgunduz. and E. Karshgil,
“Handwritten Signature Verification Using Image Invariants
and Dynamic Features, Proceedings of the 13th European
Signal Processing Conference EUSIPCO 2005, Antalya
Turkey, and 4th-8th
September, 2005.

Design of digital signature verification algorithm using relative slope method

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