How to reduce the interdomain routing instability in multidomain optical networks is a burning issue of the day. An approach called active choke of interdomain routing (ACIR) is proposed to decrease the instability caused by temporary node overload. In this approach, when the network load increases to a certain value, the traffic requests without a minimum number of spanned domains are rejected directly or with a fixed or floating probability, while the rest are accepted. With the wavelength continuity constraint, numerical results on two network topologies demonstrate that the ACIR approach provides better blocking performance during heavy traffic and lower load at both nodes and domain controllers.
Burst contention resolution is one of the most important issues in optical burst switching (OBS) networks. In this paper, an O/E/O conversion and electronic storage mechanism for contention resolution is proposed. Compared with fiber delay lines (FDL) O/E/O strategy can provide much longer and continuous delay time for the contending bursts, which can significantly reduce burst loss rate. For this mechanism, a new burst scheduling algorithm called Shortest Delay-
Best Fit (SD-BF) is proposed here to improve bandwidth utilization. In a network, O/E/O can be implemented with FDL to achieve a better performance while reducing node cost. In this paper, a semi-share structure for this combination strategy is proposed to balance the cost and performance. Numerical results show that a better performance is achieved by the combination strategy in the long haul back-bone networks. We also investigate the maximum electronic RAM capacity needed in the nodes to support O/E/O storage, and how to implement Quality-of-Service (QoS) with O/E/O storage.
Line detection is one of the most long-lasting problems in image processing. In this paper, we address the problem of detecting strong/weak lines and long/short lines in gray level images simultaneously. Our technique consists of three steps: image gradient enhancement, modified Hough Transform (HT) and line fitting. The gradient direction is fully exploited in our technique, which provides additional cues for weak line detection. Experiments on various images are presented to verify our approach. The results show that our technique has a superior detection rate than conventional HT algorithm, especially for short and weak lines.
A new model (3D) of OCT based on wave optics and Huygens- Fresnel Principle is derived in this paper. In this model, both axial and transverse information is included so that it can be used to discuss the image properties in both directions. The model is further simplified by narrow-band approximation and plane wave approximation. As applications of the simplified model, we developed Monte Carlo simulation programs to calculate the transverse resolution and to simulate the axial signal of our OCT system. The results well coincides the experiments.
Optical tomography is a kind of noninvasive technology in CT field using multiple photon diffusion. With the method of Monte Carlo simulation we carried out some numerical computation of the diffusion transmission disciplinarian in two kinds of simple biological texture. A ring distribution of diffuse light intensity is found and is sensitive to the incident light relative position to the absorption sphere at some certain conditions. The resolution and incident depth are also discussed through analysis of the image in numeric simulation.
Optical Coherence Tomography (OCT) is a kind of new tomography technology, which has much important application in biological, medical and material science. In this paper, we make continuations of this technology to found en face imaging of arbitrary object. This enables us to get digital information about the geometrical configuration of a sample with resolution of micrometers in a non-touching mode.
Optical coherence tomography (OCT) takes the advantage of the low coherence property of a light source to get the image of biological tissue structures. It provides important information on the contour and thickness of tissue structures, which can be of great help for clinical diagnostic procedures. Usually, the resolution of OCT image ranges from 2 to 20 microns. At the beginning of tissue pathologic changes, the foci could be located with OCT and cured in time. In this paper, some images of rabbit' femoral artery wall taken by our OCT system are presented. From these pictures, the three-layered structure coincides with the atlas well. In addition, the image of femoral artery wall with fat deposit is shown and the tunica media is thicker than that of normal vessel wall. The ability of OCT to image tissue microstructure near the cellular level make it potential for minimally invasive probing of tissue diseases. The high resolution of OCT, which is greater than any other conventional clinic imaging modality, and based on fiber, makes it particularly attractive for the assessment of early cardiovascular plaque.
Monte Carlo method is employed to simulate optical path-length- resolved reflectance from samples in optical coherence tomography. Four different models are often used in such simulations to treat the scattering and absorption process. This paper presents a detailed probability analysis on the equivalence of the four different models under certain conditions. We found that the photon's statistical contributions after the same times of scattering are equal in these four models.
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.