Hiromitsu Hama

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In the current context of increased surveillance and security, more sophisticated and robust surveillance systems are needed. One idea relies on the use of pairs of video (visible spectrum) and thermal infrared (IR) cameras located around premises of interest. To automate the system, a robust person detection algorithm and the development of an efficient(More)
In this paper we propose a novel optimal crawling strategy for next-generation multimedia search engines. We consider here a Web crawl as a two-dimensional (2D) random walker on a graph whose vertices are the Web pages and whose edges are the hyperlinks. The proposed crawler is a two-part scheme optimizing the crawling process in such a way that the average(More)
In this paper, we propose a new method for detecting tire-road contact points and estimating the position of a vehicle on a road taking the distortion in a circular fisheye image into consideration. In our proposed method, we use the distortional parameter of two concentric circles composed of the inner wheel and the outer tire by considering projection(More)
Today video surveillance systems are widely used in public spaces, such as train stations or airports, to enhance security. In order to observe large and complex facilities a huge amount of cameras is required. These create a massive amount of data to be analyzed. It is therefore crucial to support human security staff with automatic surveillance(More)
We propose a method for object-based retrieval in image and video databases. In doing so, both color and shape information is taken into account to enrich the querying capabilities for object-based retrieval. The morphological operations are performed on each uniform color region. We use three kinds of histograms: color histogram, distance histogram, and(More)
In this paper we present a novel scheme where image features are bundled into local groups. Specifically, features of Near Infrared (NIR) images extracted by using Histogram of Oriented Gradients (HOG) descriptor and those by our multislit method are bundled into a single descriptor. The method involves first localizing the spatial layout of body parts(More)
By focusing on the decoding process to improve coding efficiency, we propose an effective video coding method by employing parameter estimation in the decoding process. A bitrate reduction can be achieved when the proposed method is applied to the DC transform coefficient and the motion vector of H.264. 0.25%-0.84%.
In this paper, we explore and examine a new novel approach to image ranking systems based on some special types of Markov chain along with new concepts of popularity and relevancy measures for image database. To be specific, this approach introduces a family of special Markov chain models in which serial correlations are explicitly involved so that we can(More)