Xiaoxin Guo

The blood vessel recognition of ocular fundus

Today, iris recognition, fingerprint recognition, face recognition, voice recognition and other biometric technology are experiencing rapid development. This paper addresses a new biometric technology - skeleton recognition for blood vessel of optic fundus. The green grayscale ocular fundus image is utilized. The skeleton feature of blood vessel of optic fundus is extracted at first. After filtering treatment and extracting feature, vector curve of blood vessels is obtained. Shape curve matching is later carried out by means of reference point matching. The recognition for blood vessel optic fundus has been demonstrated in this paper to possess high recognition rate, low recognition rejection rate as well as good universality, exclusiveness and stability. With more and more progress made in extracting technology, the optic fundus blood vessel recognition is to become an effective biometric technology.

The identification and recognition based on point for blood vessel of ocular fundus

Today, iris recognition, fingerprint recognition, face recognition, voice recognition and other biometric technology are experiencing rapid development. This paper addresses a new biometric technology–the identification and recognition based on point of blood vessel skeleton for ocular fundus. The image for green gray scale of ocular fundus is utilized. The cross point of skeleton shape of blood vessel for ocular fundus using contrast-limited adaptive histogram equalization is extracted at first. After filtering treatment and extracting shape, shape curve of blood vessels is obtained. The cross point of shape for curve matching is later carried out by means of cross point matching. The recognition based on shape for blood vessel of ocular fundus has been demonstrated in this paper to possess high Identification and recognition rate, low rejection recognition rate as well as good universality, exclusiveness and stability. With more and more progress made in extracting technology, the recognition for blood vessel of optic fundus is to become an effective biometric technology.

The batch patching algorithm using dynamic cache of proxy for streaming media

The proxy cache for streaming media is the important method to economize the resources of the Internet. The cache policies influence the effect for proxy cache. In this paper, based on the clients request rate, cached the video based on segment, we proposed that the policies for batch, patch and batch patching using dynamic cache. The policies of batch and batch patching using dynamic cache based on segment enlarge the width of the batch and patching. It combines dynamic cache based on segment with the excellence of patch. Presented that allocation relation of the cache between the batch and patch using dynamic cache, and assured that batch patching using dynamic cache of proxy based on segment is optimal.

ADAPTIVE DIRECTIONAL WEIGHTED MEDIAN FILTERING

A novel filtering algorithm called adaptive directional weighted median (ADWM) filtering is proposed. The ideas of the directional filtering and the weighted median filtering are combined with each other to construct the ADWM filter model, which is a highly nonlinear image smoothing and enhancement technique. The use of the variance of the moving window and the base variance supports the adaptivity of the ADWM filter. The ADWM filter has the features of directional filter, which is especially effective at preserving edges, and the features of center weighted median (CWM) filter, which can reduce random noise, and moderate (amounts) of impulsive noise also, to some extent, as well as preserve the details via adaptively determining the weight of the center pixel according to the lowest variance of pixels within all the sub-windows.

Complete 3D model reconstruction using two types of depth sensors

We propose a fast and simple application system of 3D model reconstruction. We acquire range images by using a combination of a regular camera and two types of depth sensors. The reconstruction of a 3D model consists of four key steps: (i) Initial alignment either feature tracking or the 4-points congruent sets algorithm is used to align surfaces captured at different frames. (ii)The iterative closest point (ICP) method is applied to further align the piecewise surfaces from the last step. (iii) The surfaces are merged into a whole 3D model by the volumetric method. (iv) In the refinement step, we fill holes and produce a complete 3D model that approximates the original model with robust repair of polygonal models. At last, we present the experimental results which show that the errors between our reconstructed model and the ground truth are less than 1%.

Method for Acoustic Leak Detection of Fast Reactor Steam Generator Based on Wavelet Noise Elimination

It is one of main measures for safe operation of the fast reactor to use acoustic leak detecting technology to realize early detection for water/steam leak of steam generator in fast reactor nuclear power station. Based on experimental data about sodium loop experiment completed by Liquid Metal Laboratory of Tsinghua University, this paper investigates the application of wavelet noise elimination in detection for water/steam leak of fast reactor steam generator. The result shows that wavelet noise elimination can greatly improve signal-noise ratio, and it is really a highly effective method for timely and correct leak detection of the steam generator

The dynamic cache algorithm of proxy for streaming media

The transmission streaming media becomes a challenging study problem for the Web application. The proxy cache for streaming media is an efficient method to solve this problem. In proxy cache, prefix cache is to cache the initial part of the streaming media in the proxy cache, so that there is no startup delay for the inquest of the clients. Segmentation based cache is to cache the length of streaming media, according to the inquest frequency of the clients so as to save the web resources; The proxy cache and the segmentation based cache are both pre-drawing cache methods. In this paper, we proposed the algorithm of high efficient dynamic cache method, based on prefix cache and segmentation based cache strategy. The algorithm carries out real time dynamic cache in the proxy cache and makes the dynamic cache with batch and patching algorithm, transmitted and proxy cached by the server, deal with the requests of more than one clients within a relatively short period of time. Therefore, the web resources used by patching channel and regular channel and release the network burden of the server. Event-driven simulation, introduced to evaluate this algorithm, is very efficient.

Complete 3D model reconstruction using a depth sensor

We propose a fast and simple application system of 3D model reconstruction. We acquire range images by using a combination of a regular camera and a depth sensor. The reconstruction of a 3D model consists of four key steps: (i) Initial alignment either feature tracking or the 4-points congruent sets algorithm is used to align surfaces captured at different frames. (ii)The iterative closest point (ICP) method is applied to further align the piecewise surfaces from the last step. (iii) The surfaces are merged into a whole 3D model by the volumetric method. (iv) In the refinement step, we fill holes and produce a complete 3D model that approximates the original model with robust repair of polygonal models. At last, we present the experimental results which show that the errors between our reconstructed model and the ground truth are less than 1%.

Image Restoration with Intensity Preservation from Fluorescein Angiogram Sequences

Intensity degradations are a familiar problem for fluorescein angiogram sequences. In this paper, we attempt to restore a noisy fluorescein angiogram, and to keep the high intensity pixels from degrading. To this end, we incorporate a new constraint, called intensity constraint, to Millers regularization formulation with a smoothness constraint. Considering the specified requirement for fluorescein angiograms, we also modify the Q-th order converging algorithm for implementation purpose. In our scheme, including its formulation and implementation, image restoration can not only handle the traditional problems, such as blur and noise, but also achieve an important feature, intensity preservation. The experiments show that our approach has satisfactory results in the two aspects.

Effects on density resolution of CT image caused by nonstationary axis of rotation

This paper discusses the negative effect on density resolution of computerized tomography (CT) image caused by the nonstationary axis. Noise introduced and noise propagation has been analyzed according to the integral formula of reconstructing CT image. Through analyzing and deducing we get the Signal Noise Ratio which is influenced by position noise in the special position of some simple situation. Furthermore, having provided the result of SNR in other position by utilizing the method of numerical computation and having got the conclusion that the SNR is dropped in the position of edge of image and the main part of the image is almost not impacted. The simulative image agrees well with the conclusion. The result provides theoretic reference for confining the shaking quantity of the rotating axis in large CT system.