M. Mani Roja

Face recognition using discrete cosine transform for global and local features

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 × 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.

Text-Independent Speaker Recognition for Low SNR Environments with Encryption

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.

ElGamel Encryption for Biometric Database Protection

critical issues in biometric systems are protecting the template of a user which is stored in a data base. An attack against the stored templates constitutes a major security and privacy threat in a biometric system. Proper use of cryptography greatly reduces the threats in biometric system as the attackers have to find the decryption key and template. This paper proposes an approach for biometric database protection using ElGamel encryption technique. The algorithm was successfully tested on a binary image, gray image and a colour image.

A Fusion Approach for Signature Recognition

new approach for the personal authentication using signatures is presented. This paper attempts to improve the performance of signature based authentication system by integrating multiple algorithms. The signatures are acquired using digital pen tablet and then features are extracted. These features are then examined for their combined performances. Our experimental results on the image data set from 30 users confirm the advantages of our fusion technique using simple image acquisition.

Performance analysis of latent fingerprint enhancement techniques

Fingerprint Enhancement is an important step used to improve the accuracy and rate of automated detection of fingerprints. Enhancing the latent fingerprints facilitates the extraction of minutiae from the fingerprint image. In this paper, two methods of latent fingerprint enhancement are carried out. The first uses Histogram Equalization for enhancing the latent fingerprint. The second method uses a novel approach of Binarization followed by Wiener filtering and an additional Median filter. The improvements in the image are then analyzed based on their entropy, contrast and moment.

Audio Watermarking with Encryption

Watermarking is an effective means of hiding data, thereby protecting the data from unauthorized or unwanted viewing. Watermarks have been proposed previously as a way for protecting the data. This digital signature could discourage copyright violation, and may help determine the authenticity and ownership of an image. In this paper, audio watermarking is done with the help of Discrete Fourier Transform (DFT). To enhance the security of the watermark, pseudo noise (PN) based encryption is used. Keywords—Water Marking; DFT; Encryption; PN sequence; MSE

Design & implementation of an automated dual-axis solar tracker with data-logging

With the growing demand for energy worldwide, a drastic shortage of the non-renewable sources of energy will be observed in the future. Hence, there is a need to replace these resources with those that are renewable. For collecting solar energy, the current fixed configuration of solar panels is used which provides only 22 percent efficiency as it faces the sun only for a limited amount of time per day. In this work, an automated dual axis solar tracker design which also logs data such as solar irradiation, battery voltage and temperature on board has been designed and implemented. The solar tracker circuit uses an ATMega328, four LDRs, and two servo motors. The output voltage efficiency of the automated tracking configuration has been compared and analyzed with a fixed configuration solar panel tilted at an angle of 20 degrees.

Dual-Layer Video Encryption using RSA Algorithm

This paper proposes a video encryption algorithm using RSA and Pseudo Noise (PN) sequence, aimed at applications requiring sensitive video information transfers. The system is primarily designed to work with files encoded using the Audio Video Interleaved (AVI) codec, although it can be easily ported for use with Moving Picture Experts Group (MPEG) encoded files. The audio and video components of the source separately undergo two layers of encryption to ensure a reasonable level of security. Encryption of the video component involves applying the RSA algorithm followed by the PN-based encryption. Similarly, the audio component is first encrypted using PN and further subjected to encryption using the Discrete Cosine Transform. Combining these techniques, an efficient system, invulnerable to security breaches and attacks with favorable values of parameters such as encryption/decryption speed, encryption/decryption ratio and visual degradation; has been put forth. For applications requiring encryption of sensitive data wherein stringent security requirements are of prime concern, the system is found to yield negligible similarities in visual perception between the original and the encrypted video sequence. For applications wherein visual similarity is not of major concern, we limit the encryption task to a single level of encryption which is accomplished by using RSA, thereby quickening the encryption process. Although some similarity between the original and encrypted video is observed in this case, it is not enough to comprehend the happenings in the video.

Cascaded Transforms for Signature Recognition with Image Registration

Biometrics methods of human identification have gained much attention recently, mainly because they easily deal with most problems of traditional identification, since users are identified by who they are, not by something they have to remember or carry with them. This paper attempts to improve the performance of signature based authentication system by cascading orthogonal transforms. The signatures are acquired using WACOM digital pen tablet and then features are extracted. Our experimental results on the image data set from 75 users, confirm the advantages of our cascaded approach over unimodal approaches. It should be noted that a distinct advantage of the proposed system is that it does not require multiple signature samples for training.

Perturbation analysis of square lattice photonic crystal fibers

A square lattice photonic crystal fiber is studied by means of finite element method. Properties of single mode behaviour, effective area and dispersion are investigated.