Koji Wakimoto

Video hypermedia authoring using automatic object tracking

Video hypermedia systems enable users to retrieve information related to an object by selecting it directly in a video sequence. In video hypermedia systems, users must locate an anchor position according to the motion of the object. But it is very laborious to locate an anchor to its suitable position according to the motion of the object. We have proposed a new automatic object tracking method and implemented it to the system. A feature of this method is that it includes various automatic error correction algorithms. We evaluated this system on effectiveness on reducing human operations. As a result, the number of operations reduced to 30.3% of the former method, and the time of operations reduced to 60.1% of the former method.

Evaluation of Positioning Accuracy for the Pedestrian Navigation System

Today, pedestrian navigation systems for mobile phones use 2-dimensional maps as a navigation media in general. But 3-dimensional maps or scenery images are easier to understand for users than 2-dimensional maps. To use 3-dimensional maps or scenery guidance, the measuring accuracy of user position is essential to understand guidance images. In this paper, we will present a pedestrian navigation system using real scenery photographs as a navigation media, and based on experiments we will report the evaluation result of influence of positioning accuracy on the understandability of navigation. It is shown that 3 meters or less error of positioning is tolerable for pedestrian navigation systems using scenery images.

Content-based retrieval applied to drawing-image databases

In this paper, a method of image information retrieval is presented. The method employs a new similarity measure between graph representations of images. The measure is effective for drawing images that describe logical meaning by their structure. Most of the currently available image database systems offer retrieval functions called key word retrieval, where users specify key words such as titles, attributes, and categories of themes. But it is not easy for the users to select suitable key words according to the purpose of retrieval. So recently some retrieval functions called similarity retrieval have been proposed, where users specify key images by means of examples, sketches, and icons. We are developing a drawing image database system that stores plant diagrams. The system scans, recognizes, and stores plant diagrams. Then users can refer to any parts of the diagrams according to their needs. The system is used as a help to plant observation and control. To realize similarity retrieval for logically structured drawings like plant diagrams, we introduced a graph representation of drawings, which is suitable to deal with their logical structure. Then we defined a similarity measure between them. In this paper, effectiveness of the similarity measure and applicability to plant diagrams are discussed and some experimental results are shown.

Content-based Management of Video in a Multimedia Authoring Environment

This paper describes architecture and implementation of a multimedia authoring environment which features content-based management of video.The goal of our work is to provide multimedia application developers with a useful video database, where they gather video materials from various sources, store them in a organized format, and use them in multimedia applications. The principal design concepts are that (1) it should have a flexible means to store video materials in a organized format so that video clips can be retrieved easily, and that (2) it should have a view to each application so that various applications can share the video materials.To meet these requirements we designed a multimedia authoring system based on a video object model. The video object model features (1) a method to attach annotations not only to scenes but also to things shot in the video, and (2) a method to define video clips independently from physical video data.Our experiences in using the system to develop a multimedia CAI application are also described to show the advantages of our system.

A similarity retrieval method of drawings based on graph representation

An efficient method to retrieve necessary information from drawings for plant diagrams, logic circuit diagrams, etc. stored in a database is presented. In the image information retrieval systems currently in use, a keyword is assigned to each diagram and information is retrieved by the user by giving the keyword. When the features of the desired image are not registered as a keyword, however, its retrieval becomes difficult. In this paper a method is proposed in which the user shows features of the desired diagram using a sample diagram and a section similar to the sample diagram is retrieved. In this research, diagrams consisting mainly of symbols and connecting lines are considered. This kind of diagram is represented by a graph and similarities in topological features between the sample graph and graph representations of the diagrams in the database are evaluated. The retrieval is then performed based on the value obtained. The results of an experiment conducted using plant diagrams show that similar diagrams can be retrieved using this method.

An interactive tool for recognizing structured figures with variable shapes

Abstract. In electric power supply, railway, and other companies with many facilities, facility management is a laborious task. To realize a computerized facility management system, numerous paper-based facility maps should be stored in a database. In this paper, we present a system that constructs a facility management database by interpretation of paper-based facility maps. This system can automatically recognize structured figures with variable shapes on maps, while conventional methods cannot recognize these figures. And this system can easily generate relational data between facilities and character strings on maps. We compare our recognition method of structured figures with variable shapes with a conventional recognition method, and show the effectiveness of our system.

Representation and coding of large-scale 3D dynamic maps

combined with depth and color measurements of the surrounding environment. Localization could be achieved with GPS, inertial measurement units (IMU), cameras, or combinations of these and other devices, while the depth measurements could be achieved with time-of-flight, radar or laser scanning systems. The resulting 3D maps, which are composed of 3D point clouds with various attributes, could be used for a variety of applications, including finding your way around indoor spaces, navigating vehicles around a city, space planning, topographical surveying or public surveying of infrastructure and roads, augmented reality, immersive online experiences, and much more. This paper discusses application requirements related to the representation and coding of large-scale 3D dynamic maps. In particular, we address requirements related to different types of acquisition environments, scalability in terms of progressive transmission and efficiently rendering different levels of details, as well as key attributes to be included in the representation. Additionally, an overview of recently developed coding techniques is presented, including an assessment of current performance. Finally, technical challenges and needs for future standardization are discussed.

Method of line drawing recognition based on intersection model

Proposed here is a method of drawing recognition that allows correct separation and recognition of lines, even when many similar lines form dense and complicated intersections. With previous techniques for line recognition, tracing-type methods based on such line properties as straightness are generally employed. As to junctions and intersections between graphic objects, trial-and-error methods have been studied that offer line recognition by means of repetitive generation of hypotheses based on some global constraints, and verification of these hypotheses. Such methods prove to be poor, however, at recognition of relations between lines within complicated intersection areas. In this paper, geometric patterns of line intersection areas are modeled under certain constraints, and it is made clear that these patterns may be considerably reduced in number by using border points between an intersection area, and its incoming and outgoing lines. Using this intersection model, a method is proposed to recognize line drawings, and efficiency of the method is verified by evaluation tests.