Technique to correct yellowing and foxing in antique books

New algorithms for the automatic restoration of antique documents affected by foxing and by yellowing deterioration processes are proposed in the paper. The physical restoration of such objects is both expensive and hard to carry out by nonspecialised library personnel. The proposed algorithms ensure fast and less expensive results, and can be used also by nonqualified operators. Moreover, these techniques improve the performance of optical character recognition operators.     

Application-Specific Instruction-Set Processor for Retinex-Like Image and Video Processing

This brief presents an application-specific instruction-set processor (ASIP) for real-time Retinex image and video filtering. Design optimizations are addressed at algorithmic and architectural levels, the latter including a dedicated memory structure, an adapted pipeline, bypasses, a custom address generator and special looping structures. Synthesized in CMOS technology, the ASIP stands for its better energy-flexibility tradeoff versus reference ASIC and digital signal processing Retinex implementations.     

A flexible FPGA implementation for illuminance–reflectance video enhancement

Digital cameras, new generation phones, commercial TV sets and, in general, all modern devices for image acquisition and visualization can benefit from algorithms for image enhancement suitable to work in real time and preferably with limited power consumption. Among the various methods described in the scientific literature, Retinex-based approaches are able to provide very good performances, but unfortunately they typically require a high computational effort. In this article, we propose a flexible and effective architecture for the real-time enhancement of video frames, suitable to be implemented in a single FPGA device. The video enhancement algorithm is based on a modified version of the Retinex approach. This method, developed to control the dynamic range of poorly illuminated images while preserving the visual details, has been improved by the adoption of a new model to perform illuminance estimation. The video enhancement parameters are controlled in real time through an embedded microprocessor which makes the system able to modify its behavior according to the characteristics of the input images, and using information about the surrounding light conditions.     

Algorithmic and architectural design for real-time and power-efficient Retinex image/video processing

This paper presents novel algorithmic and architectural solutions for real-time and power-efficient enhancement of images and video sequences. A programmable class of Retinex-like filters, based on the separation of the illumination and reflectance components, is proposed. The dynamic range of the input image is controlled by applying a suitable non-linear function to the illumination, while the details are enhanced by processing the reflectance. An innovative spatially recursive rational filter is used to estimate the illumination. Moreover, to improve the visual quality results of two-branch Retinex operators when applied to videos, a novel three-branch technique is proposed which exploits both spatial and temporal filtering. Real-time implementation is obtained by designing an Application Specific Instruction-set Processor (ASIP). Optimizations are addressed at algorithmic and architectural levels. The former involves arithmetic accuracy definition and linearization of non-linear operators; the latter includes customized instruction set, dedicated memory structure, adapted pipeline, bypasses, custom address generator, and special looping structures. The ASIP is synthesized in standard-cells CMOS technology and its performances are compared to known Digital signal processor (DSP) implementations of real-time Retinex filters. As a result of the comparison, the proposed algorithmic/architectural design outperforms state-of-art Retinex-like operators achieving the best trade-off between power consumption, flexibility, and visual quality.

A Globally Convergent Matricial Algorithm for Multivariate Spectral Estimation

In this paper, we first describe a matricial Newton-type algorithm designed to solve the multivariable spectrum approximation problem. We then prove its global convergence. Finally, we apply this approximation procedure to multivariate spectral estimation, and test its effectiveness through simulation. Simulation shows that, in the case of short observation records, this method may provide a valid alternative to standard multivariable identification techniques such as Matlab's PEM and Matlab's N4SID.     

Edge extraction by a class of second-order nonlinear filters

The application of a class of nonlinear 2-D digital filters, based on the discrete Volterra series, as edge detectors is considered. Independence on edge orientation is achieved by the use of symmetry conditions on the coefficients. Two examples are presented.     

Fuzzy operator for sharpening of noisy images

An operator is presented which is able to sharpen the details of an image, by applying fuzzy reasoning rules to the input luminance values. The particular processing rules used allow the operator to be insensitive to noise.<>     

A fuzzy operator for the enhancement of blurred and noisy images

Rule-based fuzzy operators are a novel class of operators specifically designed in order to apply the principles of approximate reasoning to digital image processing. This paper shows how a fuzzy operator that is able to perform detail sharpening but is insensitive to noise can be designed. The results obtainable by the proposed technique in the enhancement of a real image are presented.     

The amino acid sequences of two acylphosphatase isoforms from fish muscle (Lamna nasus)

Two acylphosphatase isoenzymes have been purified from Lamna nasus muscle, and their complete amino acid sequences have been determined. The former (E1) consists of 99 amino acid residues, while the latter (E2) consists of 102 residues. Both are acetylated at their N termini. E1 has the FFRK active site motif characteristic of all common-type acylphosphatase isoenzymes, whereas E2 contains the CFRM active site motif characteristic of all muscle-type acylphosphatase isoenzymes. They have quite similar kinetic properties. The comparison of sequences of fish E1 and E2 isoenzymes with other known mammalian and bird acylphosphatases reveals that the E2 isoenzyme has an N terminus tail, four residues long, similar to those previously found in all known bird species muscle-type isoenzymes. Among organ-common-type acylphosphatases about 50% of residues are completely conserved, whereas about 60% of muscle-type acylphosphatase residues are completely conserved, indicating that the latter type of isoenzyme has a slower evolutionary rate than the former. The sequences of E1 and E2 acylphosphatases from L. nasus represent the first primary structures of this kind of enzyme determined among fish species.     

Myoepithelial-epithelial carcinoma of the parotid: cyto-histological description of a case

We report a case of epithelial-myoepithelial carcinoma of the parotid gland arised in a 72 years-old woman, in which the diagnosis was suspected on fine-needle aspiration and confirmed on surgical specimen. Immunohistochemical evidence for the dual differentiation (glandular and myoepithelial) of the tumour was obtained both on surgical specimen and cytological inclusion. Morphological features and proliferating index (MIB1) analysis suggest that this case is an intermediate grade malignant neoplasm. Main differential diagnosis of the epithelial-myoepithelial carcinoma with predominantly clear cell tumours of the salivary glands were discussed.