In this paper, several methods of image analysis such as fast Fourier transform, power spectrum, and t phase angle, have
been used to a pattern formation system to get the features of their own. Complex patterns such as hexagon, quasi-crystal,
and superlattice patterns have been analyzed. The mechanisms of all stationary patterns are attributed to Turing
instability. These patterns have a unique characteristic wave number that equals to Turing mode. It is found that these
complex structures are composed of two simple component hexagonal pattern that are co-rotated by an angle. Both
superlattice pattern and quasi-crystal pattern have been constructed as the angle is varied. Another type of superlattice
pattern named as super-hexagonal pattern is resulted from interactions between Turing mode and its harmonics.
Diverse stable localized states respectively with hexagonal, heptagonal and enneahedral symmetry have been
observed in a dielectric barrier discharge system with two water electrodes. The interacting process of different localized
clusters due to the attractive interaction is shown. The spatiotemporal dynamics of the localized hexagonal states are
measured by photoelectric method. It is found that the seven filaments composing a hexagonal cell discharge nearly at
the same time, with the light intensity of the central filament much stronger than its neighboring six ones. Magnifying the
light signal, however, it is found that the discharge moment of the central filament always precedes that of others
actually.
The variations of the intensity of argon (2P→1S) spectral lines with various gas mixing ratios in dielectric barrier discharge (DBD) in air/Ar and N2/Ar admixtures are studied. The relative intensity of Ar I I750.39nm/I763.51nm as a function of experiment conditions (pressure, applied voltage and frequency) in Ar discharge is also measured. In air/Ar and N2/Ar admixtures, it is observed that the higher levels of N2 molecules have quenching selectivity for Ar (2P→1S) spectral lines, and the relative intensity of Ar I I750.39nm/I763.51nm increases with increasing air or N2 concentration in two admixtures, respectively. Both Ar (2P→1S)spectral lines and the relative intensity of Ar I I750.39nm/I763.51nm in N2/Ar admixture are higher than that in air/Ar admixture under the same air and N2 concentration in two admixtures. The relative intensity of Ar I I750.39nm/I763.51nm increases from 0.81 to 1.73 when the concentration of air changes from 10% to 73%, but the relative intensity changes from 1.03 to 3.51 when the concentration of N2 increases from 10% to 73% in N2/Ar admixture at a applied voltage of 10kV, a frequency of 26kHz and an atmosphere pressure. Moreover, in Ar discharge, the results demonstrate that the pressure has great effect on the relative intensity of Ar I I750.39nm/I763.51nm, which decreases with increasing the pressure. But it changes slightly with the applied voltage and the frequency.
In this work, a rich variety of emission spiral patterns have been obtained in dielectric argon/air barrier discharge (DBD) system with a special designed water electrodes setup. We investigate the characteristics of spiral patterns with two kinds of different sidewall materials. By analyzing the image and the light signals of the patterns, it is found that spiral patterns with different sidewall material have different characteristics. The profile of the intensity distribution curve under the glass sidewall appears as a sinusoidal oscillation, while displays in relaxation oscillation mode under plastic sidewall. The space frequency spectrum of spirals under glass sidewall contains only one order spectrum, while the space spectrum of spirals under plastic sidewall contains more than two orders of space frequency spectrum. The experiment results indicate that the sidewall material may affect the excited property of the discharge system.
Edge detection is one of the most demanding tasks in optical image processing for artificial vision and image matching works. In this paper, the self organization theory is used for edge detection. A new algorithm based on a two variable reaction-diffusion equations is proposed. A stable edge pattern can be obtained by choosing suitable control parameters. Compared with the conventional methods, such as Soble, Prewitt and Robert detectors, the new algorithm indicates a higher accuracy and continuity for the image. Moreover, it can also extract exactly the edge of the human face image.
A special dielectric barrier discharge system with two liquid electrodes and a special optical system are designed to study the spatiotemporal dynamics of nonlinear patterns. A rich variety of patterns including square pattern, hexagon pattern, spiral and square superlattice pattern have been obtained. The spatio-temporal dynamics of square superlattice pattern is investigated. Results show that it is an interleaving of two different transient square sublattices with the emerging sequence of S-L-L-S-L-L in one cycle of the applied voltage. The light signals of the two sublattices indicate that the interval of the emergence of each sublattice is at an order of 0.1 μs.
KEYWORDS: Image processing, Dielectrics, Spatial frequencies, MATLAB, Physics, Digital imaging, Digital cameras, Electrodes, Analytical research, Control systems
Pattern formation is a process by which a spatially uniform state loses stability to a non-uniform state. A usual effective method for studying the property of patterns is to take pictures or record images of the patterns with digital cameras and get useful information from them. In this work, the structure, the spatial frequency spectrum of the patterns, the precise location of the discharge filaments center and the distribution of the light emission density of filaments are analyzed with Matlab6.1. This work can provide a beneficial reference for researchers who study pattern dynamics in DBD system or other systems.
Dielectric barrier discharge is a novel system for studying the pattern formation. In this system, spiral pattern has been observed for the first time. For the element of the pattern emits itself, the image can be obtained to give some information about the behavior of the spiral pattern. The image of spiral pattern is analyzed based on the software Matlab6.1. The spatial distribution of the intensity in the image gives a normal spiral structure. The temporal distribution of the intensity shows that the spiral pattern has a periodical behavior in a second time scale. All of the results are consistent with the theoretical simulations.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.