Monica Borda

Fundamentals in information theory and coding

Information trans mission systems (ITS).- Statistical Information Model of an ITS.- Source Coding.- Coding for Noiseless Channels.- Cryptography Basics.- Channel Coding.

DNA secret writing techniques

The paper presents the principles of bio molecular computation (BMC) and several algorithms for DNA (deoxyribonucleic acid) steganography and cryptography: One-Time-Pad (OTP), DNA XOR OTP and DNA chromosomes indexing. It represents a synthesis of our work in the field, sustained by former referred publications. Experimental results obtained using Matlab Bioinformatics Toolbox and conclusions are ending the work.

DNA Cryptographic Algorithms

DNA has a great cryptographic strength, its binding properties between nucleotides bases (A—T, C—G) offer the possibility to create self-assembly structures which are an efficient means of executing parallel molecular computations; its storing capabilities are enormous, a gram of DNA includes 1021 bases equivalent to 108 terra-bytes. Actual implementations don’t exceed laboratory level, are expensive and require time. Simple and effective algorithms are quested in order to bring DNA computing on digital level and use it on large scale. This paper presents two original DNA cryptographic algorithms based on existing ideas described in related literature: (1) public key encryption of binary data followed by its transform in DNA digital sequence; (2) XOR one-time-pad cryptographic algorithm, where binary data is transformed in chemically generated DNA structures named tiles.

Flow coherence diffusion. linear and nonlinear case

The paper proposes a novel tensor based diffusion filter, dedicated for filtering images composed of line like structures. We propose a linear version of nonlinear diffusion partial derivative equation, previously presented in [5]. Instead of considering nonlinearity in the image evolution process we are only including it at the computation of the diffusion tensor. The unique tensor construction is based on an adaptive orientation estimation step and yields a significant reduction of the computational complexity. The properties of the filter are analyzed both theoretically and experimentally.

Mixed anisotropic diffusion

This paper deals with the filtering and the enhancement of strongly oriented patterns. We propose a new filter combining scalar and tensor based diffusivities. The computation of an orientation confidence allows its to choose the best strategy to locally diffuse the gray levels. We show that this approach overcomes some drawbacks of the classical methods like corner smoothing or pinhole effect. The proposed method was applied on digital images of engravings. This type of images contain strongly oriented patterns and a large amount of details that have to be preserved during the diffusion.

FPGA based system for automatic cDNA microarray image processing

Automation is an open subject in DNA microarray image processing, aiming reliable gene expression estimation. The paper presents a novel shock filter based approach for automatic microarray grid alignment. The proposed method brings up significantly reduced computational complexity compared to state of the art approaches, while similar results in terms of accuracy are achieved. Based on this approach, we also propose an FPGA based system for microarray image analysis that eliminates the shortcomings of existing software platforms: user intervention, increased computational time and cost. Our system includes application-specific architectures which involve algorithm parallelization, aiming fast and automated cDNA microarray image processing. The proposed automated image processing chain is implemented both on a general purpose processor and using the developed hardware architectures as co-processors in a FPGA based system. The comparative results included in the last section show that an important gain in terms of computational time is obtained using hardware based implementations.

Image Watermarking Based on the Discrete Wavelet Transform Statistical Characteristics

The current paper proposes a robust watermarking method for still images that embeds a binary watermark into the detail subbands of the image wavelet transform. The perceptually significant coefficients are selected for each subband using a different threshold. The threshold is computed based on the statistical analysis of the wavelet coefficients. For greater invisibility of the mark, the approximation subband is left unmodified. The watermark is embedded several times to achieve robustness. The method is tested against different types of attacks (lossy compression, AWGN, scaling, cropping, intensity adjustment, filtering and collusion attack). The proposed method was compared with a state-of-the-art watermarking method, highlighting its performances

New instantaneous frequency estimation method based on image processing techniques

The aim of this paper is to present a new method for the estimation of the instantaneous frequency of a frequency modulated signal, corrupted by additive noise. Any time-frequency representation of an acquired signal is concentrated around the instantaneous frequency law of its useful component (the projection of the ridges of the time-frequency representation on the time-frequency plane) and realizes the diffusion of its noise component. So, extracting the ridges of the time-frequency representation, the instantaneous frequency of its useful component can be estimated. In this paper a new time-frequency representation is proposed. Using the image of this new time-frequency representation, its ridges can be extracted with the aid of some mathematical morphology operators. This is a ridges detection mechanism producing the projection on the time-frequency plane. This projection represents the result of the proposed estimation method. Some simulations prove the qualities of this method.

Adaptive Microarray Image Acquisition System and Microarray Image Processing Using FPGA Technology

The present paper proposes an adaptive hardware implementation for a microarray image acquisition system, which is mandatory for implementing hardware algorithms for processing microarray images. Processing techniques for microarray image are also described, together with a hardware implementation of a spot border detection algorithm. The hardware implementation takes advantage of parallel computation capabilities offered by FPGA technology. Results which prove time and cost efficiency are presented for both hardware implementations.

A PDE-Based Approach to Three-Dimensional Seismic Data Fusion

We present a new method for the denoising and fusion, which is dedicated to multiazimuth seismic data. We propose to combine low-level fusion and diffusion processes through the use of a unique model based on partial differential equations. The denoising process is driven by the seismic fault preserving diffusion equation. Meanwhile, relevant information (as seismic faults) is injected in the fused 3-D images by an inverse diffusion process. One of the advantages of such an original approach is to improve the quality of the results in case of noisy inputs, which are frequently occurring in seismic unprocessed data. Some examples on synthetic and real seismic data will demonstrate the efficiency of our method.