Informatica

The paper describes methods for generating image watermark for asymmetric key based watermark embedding and detection scheme in wavelet domain. The proposed method combines DWT-based watermarking and the ability to verify watermark using reliable methods of asymmetric coding. The watermark scheme is developed to be directly incorporated into JPEG2000 image coding standard, while it can be used in existing image coding standards. In presented watermarking method the application of public key infrastructure is emphasized. We use PGP (Pretty Good Privacy) public key management scheme as the element for verification of sender’s identity and also place of storing and retrieval of watermark detection keys. The most public key watermarking schemes use new, independent and cryptologically unverified keys. The reuse existing key verification and exchange infrastructure provides us cryptologically strong and verified keys.

This paper introduces a new similarity measure derived from the Common Submatrix-based measures for comparing square matrices. The novelty is that the similarity between two matrices is computed as the average area of the largest sub-matrices exactly matching and being located at the same position in the two matrices. By contrast, in the original similarity measures, the largest sub-matrices can exactly or approximately match and be located at different positions. An experiment conducted on a subset of the MNIST and NIST datasets shows that the new similarity measure is very promising in retrieving relevant handwritten character images.

The paper addresses the over-saturated protein spot detection and extraction problem in two-dimensional electrophoresis gel images. The effective technique for detection and reconstruction of over-saturated protein spots is proposed. The paper presents: an algorithm of the median filter mask adaptation for initial filtering of gel image; the models of over-saturation used for gel image analysis; several models of protein spots used for reconstruction; technique of the automatic over-saturated protein spot search and reconstruction. Experimental investigation confirms that proposed search technique lets to find up to 96% of over-saturated protein spots. Moreover the proposed flexible protein spot shape models for reconstruction are faster and more accurate in comparison to the flexible diffusion model.

In this paper, a digital watermarking algorithm for copyright protection based on the concept of embed digital watermark and modifying frequency coefficients in discrete wavelet transform (DWT) domain is presented. We embed the watermark into the detail wavelet coefficients of the original image with the use of a key. This key is randomly generated and is used to select the exact locations in the wavelet domain in which to embed the watermark. The corresponding watermark detection algorithm is presented. A new metric that measure the objective quality of the image based on the detected watermark bit is introduced, which the original unmarked image is not required for watermark extraction. The performance of the proposed watermarking algorithm is robust to variety of signal distortions, such a JPEG, image cropping, geometric transformations and noises.

The paper is devoted to analysis of the software peculiarities of the computer based ultrasonic imaging system for non-destructive) testing (NDT) applications. The developed software enables 1, 2, and 3-dimensional imaging of the intrinsic structure of the materials and measurement of their parameters.