Digital chaotic output from an optically processing element

Optics & Laser Technology

2000

A new methodology to study irregular behaviours in logic cells is reported. It is based on two types of diagrams, namely phase and working diagrams. Sets of four bits are grouped and represented by their hexadecimal equivalent. Some hexadecimal numbers correspond to certain logic functions. The influence of the internal and external tolerances, namely those appearing in the employed devices and in the working signals, may be analysed with this method. Its importance in the case of logic structures with chaotic behaviours is studied.

Section: Optical Computing Logic Cellmentioning

confidence: 70%

Section: Optical Computing Logic Cellmentioning

confidence: 99%

Analysis of irregular behaviour on an optical computing logic cell

González-Marcos

Optics & Laser Technology

2000

“…But this type of signal may be able to trigger some type of system connected with the presently reported architecture. For example, as we have shown 10 , under certain circumstances, a set of new frequencies, and no present previously may appear. These frequencies give information about the type of signal impinging on the system.…”

Section: Applications and Conclusionmentioning

confidence: 99%

Unattended motion-detection system based on the mammalian retina

Unmanned/Unattended Sensors and Sensor Networks

González‐Marcos

2004

Sensing systems in living bodies offer a large variety of possible different configurations and philosophies able to be emulated in artificial sensing systems. Motion detection is one of the areas where different animals adopt different solutions and, in most of the cases, these solutions reflect a very sophisticated form. One of them, the mammalian visual system, presents several advantages with respect to the artificial ones. The main objective of this paper is to present a system, based on this biological structure, able to detect motion, its sense and its characteristics. The configuration adopted responds to the internal structure of the mammalian retina, where just five types of cells arranged in five layers are able to differentiate a large number of characteristics of the image impinging onto it. Its main advantage is that the detection of these properties is based purely on its hardware. A simple unit, based in a previous optical logic cell employed in optical computing, is the basis for emulating the different behaviours of the biological neurons. No software is present and, in this way, no possible interference from outside affects to the final behaviour. This type of structure is able to work, once the internal configuration is implemented, without any further attention. Different possibilities are present in the architecture to be presented: detection of motion, of its direction and intensity. Moreover, some other characteristics, as symmetry may be obtained.

“…Moreover, as it was shown, this circuit has the possibility to the generation of periodic and even chaotic solutions. A precise analysis of the output characteristic versus the main variable parameters, as control signal level and data signal level, has been reported [11].…”

Section: Digital Chaos Generatormentioning

confidence: 99%

Secure transmission of information by digital chaotic signals

González‐Marcos

2004

SPIE Proceedings

Protecting signals is one of the main tasks in information transmission. A large number of different methods have been employed since many centuries ago. Most of them have been based on the use of certain signal added to the original one. When the composed signal is received, if the added signal is known, the initial information may be obtained. The main problem is the type of masking signal employed. One possibility is the use of chaotic signals, but they have a first strong limitation: the need to synchronize emitter and receiver. Optical communications systems, based on chaotic signals, have been proposed in a large number of papers. Moreover, because most of the communication systems are digital and conventional chaos generators are analogue, a conversion analogue-digital is needed. In this paper we will report a new system where the digital chaos is obtained from an optically programmable logic structure. This structure has been employed by the authors in optical computing and some previous results in chaotic signals have been reported. The main advantage of this new system is that an analogue-digital conversion is not needed. Previous works by the authors employed Self-Electrooptical Effect Devices but in this case more conventional structures, as semiconductor laser amplifiers, have been employed. The way to analyze the characteristics of digital chaotic signals will be reported as well as the method to synchronize the chaos generators located in the emitter and in the receiver.