Lorenzo Cozzella

A New Acquisition and Imaging System for Environmental Measurements: An Experience on the Italian Cultural Heritage

A new acquisition system for remote control of wall paintings has been realized and tested in the field. The system measures temperature and atmospheric pressure in an archeological site where a fresco has been put under control. The measuring chain has been designed to be used in unfavorable environments where neither electric power nor telecommunication infrastructures are available. The environmental parameters obtained from the local monitoring are then transferred remotely allowing an easier management by experts in the field of conservation of cultural heritage. The local acquisition system uses an electronic card based on microcontrollers and sends the data to a central unit realized with a Raspberry-Pi. The latter manages a high quality camera to pick up pictures of the fresco. Finally, to realize the remote control at a site not reached by internet signals, a WiMAX connection based on different communication technologies such as WiMAX, Ethernet, GPRS and Satellite, has been set up.

Superposed strokes analysis by conoscopic holography as an aid for a handwriting expert

For legal purposes there is a requirement for the validation of signatures and handwritten documents. A helpful method in this respect is the so-called superposed strokes analysis, based on the observation of some characteristics in the writing, such as some letters and their dynamics. This paper introduces a promising new technique for superposed strokes analysis based on conoscopic holography. Through a non-contact 3D measure a 3D profile is created of the superposed strokes that allows the writing dynamics to be determined, such as, for example, if a stroke was drawn clockwise or counterclockwise. We propose a 3D analysis by an opto-electronic system, in order to improve the graphology analysis for off-line signature verification.

Fragile digital watermarking by synthetic holograms

In this article is presented an application of synthetic hologram as fragile watermarking. The proposed technique is a frequency domain watermarking, based on computer generated hologram. Our technique, named Fragile Synthetic Holographic Watermarking (F-SHW), is suitable for ID Cart image authentication. In this paper, the F-SHW is applied to Color Images as well as to Gray Scale ones. The proposed schema is based on the knowledge of original mark from the Authentication Entity, for applying Image Correlation between this and the extracted one. Due to the application the mark is encrypted using a private key (symmetric schema).

Banknote security using a biometric-like technique: a hylemetric approach

Banknote security is an issue that has led in the last decades to insert, inside the banknote itself, a very high number of controlling methods with the aim of verifying possible tampering attempts. In order to distinguish the false banknotes, sophisticated means (i.e. watermark, feel of the paper, raised print, metallic threads, quality of the printing, holograms, ultraviolet features, micro-lettering, etc) are often used. The purpose of this paper is to show a new approach and related method to protect banknotes and to verify their originality, based on the idea of hylemetry (methodology conceptually similar to biometry) applied to banknotes. Specifically, the hylemetric feature used in this paper is the random distribution pattern of the metallic security fibers set into the paper pulp. The outcome of the proposed solution is to identify an original banknote using a binary sequence derived from the banknote itself.

Simple educational tool for digital speckle shearography

In this study, an educational tool has been prepared for obtaining short-term and more economic training on digital speckle shearography (DSS). Shearography non-destructive testing (NDT) has gained wide acceptance over the last decade, providing a number of important and exciting inspection solutions in aerospace, electronics and medical device manufacturing. For exploring these motivations, it is important to develop didactic tools to understand the potential of digital shearography through training and didactic courses in the field of NDT. In this paper we describe a simple tool for making one familiar with the potential of DSS in the area of education and training. The system is realized with a simple and economic optical setup and a virtual instrument based on the LabVIEW™ and DAQ.

Designing of diffractive optical element for the generation of uniform arrays of beams

A diffractive optical elements (DOEs), permits to change a wave front by means of diffraction. The proposed method has the advantage of not requiring complex computation and programming. In particular the designed process is made without computer iterative methods. The DOE, implemented by the proposed algorithm, consists of cells of equal size. Each cell is subdivided into appropriate parts. The average phase of these parts is related to the phase of the complex amplitude. The DOE phase can be easily computed according to simple formulas. In the paper designing phases and numerical simulation are reported. In particular the effect of the DOE structure quantization is considered.

Smartphone Sensors for Stone Lithography Authentication

Nowadays mobile phones include quality photo and video cameras, access to wireless networks and the internet, GPS assistance and other innovative systems. These facilities open them to innovative uses, other than the classical telephonic communication one. Smartphones are a more sophisticated version of classic mobile phones, which have advanced computing power, memory and connectivity. Because fake lithographs are flooding the art market, in this work, we propose a smartphone as simple, robust and efficient sensor for lithograph authentication. When we buy an artwork object, the seller issues a certificate of authenticity, which contains specific details about the artwork itself. Unscrupulous sellers can duplicate the classic certificates of authenticity, and then use them to “authenticate” non-genuine works of art. In this way, the buyer will have a copy of an original certificate to attest that the “not original artwork” is an original one. A solution for this problem would be to insert a system that links together the certificate and the related specific artwork. To do this it is necessary, for a single artwork, to find unique, unrepeatable, and unchangeable characteristics. In this article we propose an innovative method for the authentication of stone lithographs. We use the color spots distribution captured by means of a smartphone camera as a non-cloneable texture of the specific artworks and an information management system for verifying it in mobility stone lithography.

Laser speckle decorrelation for fingerprint acquisition

Biometry is gaining popularity as a physical security approach in situations where a high level of security is necessary. Currently, biometric solutions are embedded in a very large and heterogeneous group of applications. One of the most sensible is for airport security access to boarding gates. More airports are introducing biometric solutions based on face, fingerprint or iris recognition for passenger identification. In particular, fingerprints are the most widely used biometric, and they are mandatorily included in electronic identification documents. One important issue, which is difficult to address in traditional fingerprint acquisition systems, is preventing contact between subsequent users; sebum, which can be a potential vector for contagious diseases. Currently, non-contact devices are used to overcome this problem. In this paper, a new contact device based on laser speckle decorrelation is presented. Our system has the advantage of being compact and low-cost compared with an actual contactless system, allowing enhancement of the sebum pattern imaging contrast in a simple and low-cost way. Furthermore, it avoids the spreading of contagious diseases.

Designing of binary diffractive optical elements for beams performing

At present, the progress in optics is associated with wide use of diffractive optical elements (DOEs) generated by means of computer resources. DOEs are optical elements, which modify the wave field by diffraction. They allow the conversion of the incident wave into a transmitted wave which, after free-space propagation, has a desired distribution of its amplitude. If the wave fields and their propagation are represented as digital data, computer generated DOEs carrying out complex optical tasks can be calculated. Their potentialities are dependent by fabrication technique used, which must ensure the maximum of diffraction efficiency and of the signal-to-noise ratio in the generated optical signal. It is well known that, generally speaking, they are not quite tractable in analytical terms. For this reason, specialized numerical algorithms have been devised for designing such elements. In this paper we present a DOE design method, which not use computer iterative methods. Starting from the knowledge of the expression of the propagated field on image plane, we use simple formulas to obtain the entire information necessary to characterize the desired DOE. The DOE designed with the proposed method can equate an arbitrary complex amplitude transmission T(r) and has higher imaging accuracy than other DOEs. Even if it is possible studying any level combination, the aim of this paper is to summarize the results of simulation experiments which were carried out only to test the binary level diffractive optical elements (DOEs). In particular, starting from an incident Gaussian Beam, it is proposed a binary phase DOE which allows obtaining a flat emerging field, in a well-defined region after the DOE.

IR Fringe Projection for 3D Face Recognition

Facial recognitions of people can be used for the identification of individuals, or can serve as verification e.g. for access controls. The process requires that the facial data is captured and then compared with stored reference data. Different from traditional methods which use 2D images to recognize human faces, this article shows a known shape extraction methodology applied to the extraction of 3D human faces conjugated with a non conventional optical system able to work in “invisible” way. The proposed method is experimentally simple, and it has a low‐cost set‐up.