Publications (5)0 Total impact
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ABSTRACT: Face Recognition using Discrete Cosine Transform (DCT) for Local and Global
Features involves recognizing the corresponding face image from the database.
The face image obtained from the user is cropped such that only the frontal
face image is extracted, eliminating the background. The image is restricted to
a size of 128 x 128 pixels. All images in the database are gray level images.
DCT is applied to the entire image. This gives DCT coefficients, which are
global features. Local features such as eyes, nose and mouth are also extracted
and DCT is applied to these features. Depending upon the recognition rate
obtained for each feature, they are given weightage and then combined. Both
local and global features are used for comparison. By comparing the ranks for
global and local features, the false acceptance rate for DCT can be minimized.
11/2011;
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ABSTRACT: In the domain of Biometrics, recognition systems based on iris, fingerprint
or palm print scans etc. are often considered more dependable due to extremely
low variance in the properties of these entities with respect to time. However,
over the last decade data processing capability of computers has increased
manifold, which has made real-time video content analysis possible. This shows
that the need of the hour is a robust and highly automated Face Detection and
Recognition algorithm with credible accuracy rate. The proposed Face Detection
and Recognition system using Discrete Wavelet Transform (DWT) accepts face
frames as input from a database containing images from low cost devices such as
VGA cameras, webcams or even CCTV's, where image quality is inferior. Face
region is then detected using properties of L*a*b* color space and only Frontal
Face is extracted such that all additional background is eliminated. Further,
this extracted image is converted to grayscale and its dimensions are resized
to 128 x 128 pixels. DWT is then applied to entire image to obtain the
coefficients. Recognition is carried out by comparison of the DWT coefficients
belonging to the test image with those of the registered reference image. On
comparison, Euclidean distance classifier is deployed to validate the test
image from the database. Accuracy for various levels of DWT Decomposition is
obtained and hence, compared.
11/2011;
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ABSTRACT: Recognition systems are commonly designed to authenticate users at the access
control levels of a system. A number of voice recognition methods have been
developed using a pitch estimation process which are very vulnerable in low
Signal to Noise Ratio (SNR) environments thus, these programs fail to provide
the desired level of accuracy and robustness. Also, most text independent
speaker recognition programs are incapable of coping with unauthorized attempts
to gain access by tampering with the samples or reference database. The
proposed text-independent voice recognition system makes use of multilevel
cryptography to preserve data integrity while in transit or storage. Encryption
and decryption follow a transform based approach layered with pseudorandom
noise addition whereas for pitch detection, a modified version of the
autocorrelation pitch extraction algorithm is used. The experimental results
show that the proposed algorithm can decrypt the signal under test with
exponentially reducing Mean Square Error over an increasing range of SNR.
Further, it outperforms the conventional algorithms in actual identification
tasks even in noisy environments. The recognition rate thus obtained using the
proposed method is compared with other conventional methods used for speaker
identification.
10/2011;
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ABSTRACT: Biometric authentication systems that make use of signature verification
methods often render optimum performance only under limited and restricted
conditions. Such methods utilize several training samples so as to achieve high
accuracy. Moreover, several constraints are imposed on the end-user so that the
system may work optimally, and as expected. For example, the user is made to
sign within a small box, in order to limit their signature to a predefined set
of dimensions, thus eliminating scaling. Moreover, the angular rotation with
respect to the referenced signature that will be inadvertently introduced as
human error, hampers performance of biometric signature verification systems.
To eliminate this, traditionally, a user is asked to sign exactly on top of a
reference line. In this paper, we propose a robust system that optimizes the
signature obtained from the user for a large range of variation in
Rotation-Scaling-Translation (RST) and resolves these error parameters in the
user signature according to the reference signature stored in the database.
10/2011;
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ABSTRACT: In recent times, communication through the internet has tremendously
facilitated the distribution of multimedia data. Although this is indubitably a
boon, one of its repercussions is that it has also given impetus to the
notorious issue of online music piracy. Unethical attempts can also be made to
deliberately alter such copyrighted data and thus, misuse it. Copyright
violation by means of unauthorized distribution, as well as unauthorized
tampering of copyrighted audio data is an important technological and research
issue. Audio watermarking has been proposed as a solution to tackle this issue.
The main purpose of audio watermarking is to protect against possible threats
to the audio data and in case of copyright violation or unauthorized tampering,
authenticity of such data can be disputed by virtue of audio watermarking.
10/2011;
