Hyunchul Kang

Adaptive local binarization method for recognition of vehicle license plates

A vehicle license-plate recognition system is commonly composed of three essential parts: detecting license-plate region in the acquired images, extracting individual characters, and recognizing the extracted characters. But in the process, the problems like damage of license-plate and unequal light effect make it difficult to detect accurate vehicle license-plate region and to extract letters in that region. In this paper, to extract characters accurately in the license- plate region, a local adaptive binarization method which is robust under non-uniform lighting environment is proposed. To get better binary images, region- based threshold correction based on a prior knowledge of character arrangement in the license-plate is applied. With the proposed binarization method, 96% of 650 sample vehicle license-plates images are correctly recognized. Compared to existing local threshold selection methods, about 5% of improvement in recognition rate is obtained with the same recognition module based on LVQ.

Video cataloging system for real-time scene change detection of news video

It is necessary for various multimedia database applications to develop efficient and fast storage, indexing, browsing, and retrieval of video. We make a cataloging system, which has important information of video data. In this paper, we proposed a method to process huge amount of broadcasting data. It can detect scene-change quickly and effectively for MPEG stream. To extract the DC-image, minimal decoding is employed form MPEG-1 compressed domain. Scene-change is detected by the modified histogram comparative method that combines luminance and color component. A neural network is used to judge whether it is scene-change with an anchorperson and to raise precision of an anchorperson scene extraction.

Vehicle Recognition using NMF in Urban Scene

The vehicle recognition consists of two steps; the vehicle region detection step and the vehicle identification step based on the feature extracted from the detected region. Features using linear transformations have the effect of dimension reduction as well as represent statistical characteristics, and show the robustness in translation and rotation of objects. Among the linear transformations, the NMF(Non-negative Matrix Factorization) is one of part-based representation. Therefore, we can extract NMF features with sparsity and improve the vehicle recognition rate by the representation of local features of a car as a basis vector. In this paper, we propose a feature extraction using NMF suitable for the vehicle recognition, and verify the recognition rate with it. Also, we compared the vehicle recognition rate for the occluded area using the SNMF(sparse NMF) which has basis vectors with constraint and LVQ2 neural network. We showed that the feature through the proposed NMF is robust in the urban scene where occlusions are frequently occur.

A Vehicle Recognition Using Part-Based Representations

The vehicle recognition consists of two steps; the vehicle region detection step and vehicle identification step based on the feature extracted from the detected region. Among the linear transformations, the non-negative matrix factorization (NMF) and non-negative tensor factorization (NTF) can be used in part-based representation. So we can utilize the local features of a car as a basis vector. In this paper, we propose a feature extraction using NMF and NTF suitable for the vehicle recognition, and verify the recognition rate. We show that the proposed feature is robust in the urban scene where occlusions are frequently occur.

A Study on an Image Stabilization for Car Vision System

The image stabilization is the procedure of stabilizing the blurred image with image processing method. Due to easy detection of global motion, PA(Projection algorithm) based on digital image stabilization has been studied by many researchers. PA has the advantage of easy implementation and low complexity, but in the case of serious rotational motion the accuracy of the algorithm will be cut down because of its fixed exploring range, and, on the other hand, if extending the exploring range, the block for detecting motion will become small, then we cannot detect correct global motion. In this paper, to overcome the drawback of conventional PA, an Iterative Projection Algorithm (IPA) is proposed, which improved the correctness of global motion by detecting global motion with detecting block which is appropriate to different extent of motion. With IPA, in the case of processing 1000 continual frames shot in automobile, compared with conventional algorithm and other detecting range, the results of PSNR is improved 6.8% at least, and 28.9% at the most.

Effect of Fluoroethylene Carbonate in the Electrolyte for LiNi 0.5 Mn 1.5 O 4 Cathode in Lithium-ion Batteries

Fluoroethylene carbonate (FEC) was studied as an additive for the electrolyte in lithium ion batteries with the LiNi0.5Mn1.5O4 (LNMO) spinel cathode operating at a high potential beyond 4.7 V (vs. Li/Li ). It was found that the FEC additive was electrochemically active for the 1 charge cycle on the LNMO cathode. The presence of a large amount of FEC (more than 40 vol%) in the electrolyte caused severe side reactions with abnormally long voltage plateaus. In contrast, when the electrolyte contained less than 30 vol% FEC , the surface of the LNMO cathode was stabilized by the formation of the solid-electrolyte interphase (SEI), leading to improved cyclability. However, the resistance from the SEI limited the rate capability because of sluggish lithium transportation through the SEI and electronic insulation between the particles

Egg-shell structured LiCoO2 by Cu2+ substitution to Li+ sites via facile stirring in an aqueous copper(II) nitrate solution

For practical, high-energy lithium ion batteries, we introduce an egg-shell structured LiCoO2, enabling a credible performance with a high cut-off potential of 4.4 V, simply prepared by only stirring in 0.5 mM Cu(NO3)2 aqueous solution at room temperature without costly heat treatment. Through this, a very robust structure in which the Li+ ions in the LiCoO2 structure were substituted with Cu2+ is selectively synthesized on the surface of active material particles. The egg-shell structured LiCoO2 presents excellent cyclability and high coulombic efficiency even in a high potential range of 4.4 V (vs. Li/Li+) to allow a high specific capacity. Additionally, the surface-modified LiCoO2 reaches a high capacity at a fast discharge rate of 20C even after a high temperature cycling sequence. The intended surface modification is also carefully investigated by systematic analyses of STEM, SEM and XPS. Finally, the electrochemical performance of a graphite/surface-modified LiCoO2 full-cell exhibits an excellent capacity retention of nearly 90% over 1000 cycles. It is concluded that the surface modification method in which the LiCoO2 powder is added to a low-concentration aqueous solution of copper nitrate and stirred at room temperature is effective in improving the cycle life of LiCoO2 at high potentials.

XML Fragmentation for Resource-Efficient Query Processing over XML Fragment Stream

In realizing ubiquitous computing, techniques of efficiently using the limited resource at client such as mobile devices are required. With a mobile device with limited amount of memory, the techniques of XML stream query processing should be employed to process queries over a large volume of XML data. Recently, several techniques were proposed which fragment XML documents into XML fragments and stream them for query processing at client. During query processing, there could be great difference in resource usage (query processing time and memory usage) depending on how the source XML documents are fragmented. As such, an efficient fragmentation technique is needed. In this paper, we propose an XML fragmentation technique whereby resource efficiency in query processing at client could be enhanced. For this, we first present a cost model of query processing over XML fragment stream. Then, we propose an algorithm for resource-efficient XML fragmentation. Through implementation and experiments, we showed that our fragmentation technique outperformed previous techniques both in processing time and memory usage. The contribution of this paper is to have made the techniques of query processing over XML fragment stream more feasible for practical use.

Memory Efficient Query Processing over Dynamic XML Fragment Stream

ABSTRACT This paper is on query processing in the mobile devices where memory capacity is limited. In case that a query against a large volume of XML data is processed in such a mobile device, techniques of fragmenting the XML data into chunks and of streaming and processing them are required. Such techniques make it possible to process queries without materializing the XML data in its entirety. The previous schemes such as XFrag[4], XFPro[5], XFLab[6] are not scalable with respect to the increase of the size of the XML data because they lack proper memory management capability. After some information on XML fragments necessary for query processing is stored, it is not deleted even after it becomes of no use. As such, when the XML fragments are dynamically generated and infinitely streamed, there could be no guarantee of normal completion of query processing. In this paper, we address scalability of query processing over dynamic XML fragment stream, proposing techniques of deleting information on XML fragments accumulated during query processing in order to extend the previous schemes. The performance experiments through implementation showed that our extended schemes considerably outperformed the previous ones in memory efficiency and scalability with respect to the size of the XML data.Key Words:XML Fragment Stream, XML Query Processing, XML Labelling, Hole-Filler Model