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Background Coronary arterial aneurysms (CAAs) associated with Kawasaki disease (KD) significantly affect prognosis. However, the clinical course of CAAs and factors associated with CAA regression have not been well analyzed. Methods and Results The cohort of the Z‐Score 2nd Project Stage study, a multicenter, retrospective, cohort study involving 44 institutions in Japan including 1006 patients with KD, was examined. CAAs were classified by the z score of their internal diameter in the acute phase: small ( z z z ≥10). The lower limit of small CAA was based on the Japanese Ministry of Health, Labour and Welfare criteria. In the right coronary artery, the CAA regression rates 10 years after diagnosis were 95.5% for small, 83.2% for medium, and 36.3% for large. In the proximal left anterior descending artery, the regression rates 10 years after diagnosis were 95.3% for small, 80.1% for medium, and 28.8% for large. Cox regression analysis showed that diagnosis under the age of 1 year and onset of KD in 2010 to 2012 for the right coronary artery and the left anterior descending artery, and female for the right coronary artery were significantly associated with a high regression rate, whereas large CAAs for the right coronary artery and the left anterior descending artery were significantly associated with a low regression rate. Conclusions The current study, the largest Japanese study of its kind, found that small aneurysm, recent onset, and diagnosis under the age of 1 year predict regression, and that even giant aneurysms could regress. These data may contribute to long‐term management of coronary aneurysms. Registration URL: https://www.umin.ac.jp/ctr/ ; Unique identifier: UMIN000010606. more...

Background The aim of this study was to determine preferences regarding transfer of patients with congenital heart disease (CHD) attending a children's hospital in Japan and related factors. Methods and Results: We conducted a self-administered questionnaire survey with CHD patients >15 years of age treated at the pediatric cardiology outpatient clinic of a children's hospital. Logistic regression analysis was used to identify factors related to patient preferences regarding the transfer. One hundred and eleven of the 122 patients given a questionnaire provided valid responses (valid response rate, 91.0%). Sixty-six subjects (64.9%) reported "not being told anything specific" by their physicians about the transfer from the children's hospital, and 72 (59.5%) stated that they "wished to continue attending the children's hospital". Visiting outpatient clinic with parents (OR, 11.00; 95% CI: 2.01-60.97), having low uncertainty about continuing to attend the children's hospital (OR, 0.95; 95% CI: 0.92-0.98), and having high uncertainty about leaving the current physician (OR, 1.04; 95% CI: 1.01-1.07) were significantly related to the patient's wish to continue to attend the children's hospital. Conclusions There is a need to improve patient education regarding the opportunities for transfer, and to develop a systematic transition program for children's hospitals and aligned specialized adult CHD centers. more...

Reports indicate lower Down syndrome (DS) survival among females than among males in Australia, contrasting with female longevity in the general population. Using data on 1310 people with DS (626 females and 684 males) in Japan from five hospitals’ medical records and questionnaires completed by parents of people with DS, we investigated sex differences in congenital heart disease (CHD), which may be related to mortality. The CHD rate was significantly higher for females (354, 57%) than for males (338, 49%; p=0.010). Significantly more females (199, 32%) than males (175, 26%) underwent surgery for CHD (p=0.018). more...

Facial expressions are the straight link for showing human emotions. Psychologists have established the universality of six prototypic basic facial expressions of emotions which they believe are consistent among cultures and races. However, some recent cross-cultural studies have questioned and to some degree refuted this cultural universality. Therefore, in order to contribute to the theory of cultural specificity of basic expressions, from a composite viewpoint of psychology and HCI (Human Computer Interaction), this paper presents a methodical analysis of Western-Caucasian and East-Asian prototypic expressions focused on four facial regions: forehead, eyes-eyebrows, mouth and nose. Our analysis is based on facial expression recognition and visual analysis of facial expression images of two datasets composed by four standard databases CK+, JAFFE, TFEID and JACFEE. A hybrid feature extraction method based on Fourier coefficients is proposed for the recognition analysis. In addition, we present a cross-cultural human study applied to 40 subjects as a baseline, as well as one comparison of facial expression recognition performance between the previous cross-cultural tests from the literature. With this work, it is possible to clarify the prior considerations for working with multicultural facial expression recognition and contribute to identifying the specific facial expression differences between Western-Caucasian and East-Asian basic expressions of emotions. more...

The recent boom of mass media communication (such as social media and mobiles) has boosted more applications of automatic facial expression recognition (FER). Thus, human facial expressions have to be encoded and recognized through digital devices. However, this process has to be done under recurrent problems of image illumination changes and partial occlusions. Therefore, in this paper, we propose a fully automated FER system based on Local Fourier Coefficients and Facial Fourier Descriptors. The combined power of appearance and geometric features is used for describing the specific facial regions of eyes-eyebrows, nose and mouth. All based on the attributes of the Fourier Transform and Support Vector Machines. Hence, our proposal overcomes FER problems such as illumination changes, partial occlusion, image rotation, redundancy and dimensionality reduction. Several tests were performed in order to demonstrate the efficiency of our proposal, which were evaluated using three standard databases: CK+, MUG and TFEID. In addition, evaluation results showed that the average recognition rate of each database reaches higher performance than most of the state-of-the-art techniques surveyed in this paper. more...

Developing a childcare assisting system is highly necessary due to the lack of nursery teachers, and it will make an important progress on effective utilization of nursery teacher resources. In this paper, we proposed simultaneous children recognition and tracking system by using Kinect sensors for the childcare assisting system to provide information for the nursery teachers. Each of the children is recognized by integrating his/her personal information of color, face and motion. The tracking problem is modeled as finding the MAP solution of a posterior probability, and is solved by using Markov Chain Monte Carlo (MCMC) particle filter. Our system can recognize and robustly track each child during class activities. Trajectories, motion ranges and relative distances information can be provided for the nursery teachers to assist their childcare work. The effectiveness of our system is proved through continuous monitoring of the children in a nursery school. more...

IMPORTANCE: Few studies with sufficient statistical power have shown the association of the z score of the coronary arterial internal diameter with coronary events (CE) in patients with Kawasaki disease (KD) with coronary artery aneurysms (CAA). OBJECTIVE: To clarify the association of the z score with time-dependent CE occurrence in patients with KD with CAA. DESIGN, SETTING, AND PARTICIPANTS: This multicenter, collaborative retrospective cohort study of 44 participating institutions included 1006 patients with KD younger than 19 years who received a coronary angiography between 1992 and 2011. MAIN OUTCOMES AND MEASURES: The time-dependent occurrence of CE, including thrombosis, stenosis, obstruction, acute ischemic events, and coronary interventions, was analyzed for small (z score more...

In order to move around automatically, mobile robots usually need to recognize their working environment first. Simultaneous localization and mapping (SLAM) has become an important research field recently, by which the robot can generate a map while moving around. Both two-dimensional (2D) mapping and three-dimensional (3D) mapping methods have been developed greatly with high accuracy. However, 2D maps cannot reflect the space information of the environment and 3D mapping needs long processing time. Moreover, conventional SLAM methods based on grid maps take a long time to delete the moving objects from the map and are hard to delete the potential moving objects. In this paper, a 2D mapping method integrating with 3D information based on immobile area occupied grid maps is proposed. Objects in 3D space are recognized and their space information (e.g., shapes) and properties (moving objects or potential moving objects like people standing still) are projected to the 2D plane for updating the 2D map. By using the immobile area occupied grid map method, recognized still objects are reflected to the map quickly by updating the immobile area occupancy probability with a high coefficient. Meanwhile, recognized moving objects and potential moving objects are not used for updating the map. The unknown objects are reflected to the 2D map with a lower immobile area occupancy probability so that they can be deleted quickly once they are recognized as moving objects or start to move. The effectiveness of our method is proven by experiments of mapping under dynamic indoor environment using a mobile robot. more...

Darwin was the first one to assert that facial expressions are innate and universal, which are recognized across all cultures. However, recent some cross-cultural studies have questioned this assumed universality. Therefore, this paper presents an analysis of the differences between Western and East-Asian faces of the six basic expressions (anger, disgust, fear, happiness, sadness and surprise) focused on three individual facial regions of eyes-eyebrows, nose and mouth. The analysis is conducted by applying PCA for two feature extraction methods: appearance-based by using the pixel intensities of facial parts, and geometric-based by handling 125 feature points from the face. Both methods are evaluated using 4 standard databases for both racial groups and the results are compared with a cross-cultural human study applied to 20 participants. Our analysis reveals that differences between Westerns and East-Asians exist mainly on the regions of eyes-eyebrows and mouth for expressions of fear and disgust respectively. This work presents important findings for a better design of automatic facial expression recognition systems based on the difference between two racial groups. more...

Background The 1st nationwide survey by the Japanese Society of Pediatric Cardiology and Cardiac Surgery of acute or fulminant myocarditis (AMC/FMC) in children revealed that the survival rate of FMC was only 51.6%. The 2nd nationwide survey was performed to evaluate the recent outcomes of pediatric myocarditis.Methods and Results:Questionnaires regarding patients aged ≤18 years with AMC/FMC during the period from January 2006 to December 2011 were mailed. A total of 221 cases (age 6.5±5.3 years, 116 boys and 105 girls) were reported. There were 145 (65.6%) and 74 cases (33.5%) of AMC/FMC, respectively; the type of myocarditis was not reported in the remaining 2 cases (0.9%). Viruses were identified in 56 cases (25.3%), including coxsackie B in 9 and influenza A in 8. Histopathology by either endomyocardial biopsy or autopsy was obtained in 38 cases (19.2%). Intravenous immunoglobulin was effective in 49 (34.3%) of 143 cases. Steroid therapy was effective in 20 (32.8%) of 61 cases. Mechanical circulatory support was given in 54 cases (24.4%) and 94.2% of them were patients with FMC. The survival rates for the whole study population, acute myocarditis, and FMC were 75.6%, 91.0%, and 48.6%, respectively. Conclusions The survival rate of children with myocarditis was almost identical to that of 10 years ago. (Circ J 2016; 80: 2362-2368). more...

We present a case of fetal–neonatal acute myocarditis caused by coxsackievirus B3 infection in a term neonate. The condition manifested as high-grade atrioventricular (A-V) block prenatally. After delivery, various arrhythmias such as high-grade A-V block, ventricular tachycardia, and junctional ectopic tachycardia appeared, and we had difficulty managing these arrhythmias. This is the first report describing a case of acute myocarditis due to coxsackievirus infection presenting with fetal A-V block. This case is also unique in that it is extremely rare that various arrhythmias occur serially in one patient without left ventricular dysfunction. more...

Two people usually walk through a corridor in a parallel position. However, they spontaneously switch their positions from the parallel to the cascade position when they pass oncoming people. We propose a method for enabling a robot to switch the parallel and the cascade positions autonomously with the movement of oncoming people and obstacles when it moves with a user in a daily environment. The robot uses two laser range finders to detect walls, the user's position, as well as surrounding people and obstacles. It autonomously decides whether to go on ahead or to give way to the user. Experimental results using a robot in a daily environment show that our method was effective. more...

It is likely that in the near future, human-symbiotic robots will share people's living spaces. Since there are many objects that can cause visual occlusion in these environments, situations in which a robot cannot see an object due to occlusion whereas a user can, and vice versa, will often occur. In such situations, ideally the human-symbiotic robot should be able to interact with the user while taking into consideration the differences between their fields of view. We anticipate that such a “considerate” robot will be friendlier and provide more pleasant interactions with users. In this paper, we aim to test this anticipation. First, we propose a robot that can estimate a user's and its own fields of view and thus behave appropriately due to being aware of the difference between their perceptions. The robot estimates the orientation of the user's head and the structure of its surrounding environment using a stereo camera. By combining these results, it can inform itself of the user's and its own fields of view: that is, what they can see and what they cannot see. Next, we carry out experimental subjective evaluations of the impressions that people gain during interaction with the proposed robot. Participants who observe the interactions are asked to subjectively evaluate their impressions of the robot's behaviors. The experimental results show that the proposed robot, which can guess what the user can see and understand the differences between their different viewpoints, is perceived as more “companionable.” This ability is likely to be one of the basic requirements for achieving interactions that people interpret as “friendly” with robots and other intelligent systems. more...

Facial expression recognition has many potential applications in areas such as human-computer interaction (HCI), emotion analysis, and synthetic face animation. This paper proposes a novel framework of facial appearance and shape information extraction for facial expression recognition. For appearance information extraction, a facial-component-based bag of words method is presented. We segment face images into four component regions: forehead, eye-eyebrow, nose, and mouth. We then partition them into 4 × 4 sub-regions. Dense SIFT (scale-invariant feature transform) features are calculated over the sub-regions and vector quantized into 4 × 4 sets of codeword distributions. For shape information extraction, PHOG (pyramid histogram of orientated gradient) descriptors are computed on the four facial component regions to obtain the spatial distribution of edges. Multi-class SVM classifiers are applied to classify the six basic facial expressions using the facial-component-based bag of words and PHOG descriptors respectively. Then the appearance and shape information is fused at decision level to further improve the recognition rate. Our framework provides holistic characteristics for the local texture and shape features by enhancing the structure-based spatial information, and makes it possible to use the bag of words method and the local descriptors in facial expression recognition for the first time. The recognition rate achieved by the fusion of appearance and shape features at decision level using the Cohn-Kanade database is 96.33%, which outperforms the state-of-the-art research works. more...

Visual tracking is required by many vision applications such as human-computer interfaces and human-robot interactions. However, in daily living spaces where such applications are assumed to be used, stable tracking is often difficult because there are many objects which can cause the visual occlusion. While conventional tracking techniques can handle, to some extent, partial and short-term occlusion, they fail when presented with complete occlusion over long periods. They also cannot handle the case that an occluder such as a box and a bag contains and carries the tracking target inside itself, that is, the case that the target invisibly moves while being contained by the occluder. In this paper, to handle this occlusion problem, we propose a method for visual tracking by a particle filter, which switches tracking targets autonomously. In our method, if occlusion occurs during tracking, a model of the occluder is dynamically created and the tracking target is switched to this model. Thus, our method enables the tracker to indirectly track the “invisible target” by switching its target to the occluder effectively. Experimental results show the effectiveness of our method. more...

Photographs often have some people with closed eyes. A method to automatically output a best shot image in which all photographed members have open eyes is proposed. First a series of photographs (here 6 frames) is taken by using the continuous release function in commercial digital cameras. Blinking by each person is checked in each frame, and a frame in which all members have open eyes is selected. Blinking detection is carried out by calculating the normalized correlation between a 30 × 7 pixels open eyes template and input frames of reduced size. For a case where no frame exists in which all members have open eyes, the closed eye image is replaced by an open eye image obtained in a different frame. Experimental results for 18 photographs taken under various shooting conditions show the usefulness of the proposed method for automatically outputting a best shot image. more...

Recently, biologically inspired robots have been developed to acquire the capacity for directing visual attention to salient stimulus generated from the audiovisual environment. For the purpose of realizing this behavior, a general method is to calculate saliency maps to represent how much the external information attracts the robot's visual attention, where the audiovisual information and robot's motion status should be involved. In this paper, we represent a visual attention model where three modalities—audio information, visual information, and robot's motor status—are considered, because previous research has not considered all of them. First, we introduce a 2D density map, on which the value denotes how much the robot pays attention to each spatial location. Then we model the attention density using a Bayesian network where the robot's motion statuses are involved. Next, the information from both audio and visual modalities is integrated with the attention density map in integrate-fire neurons. The robot can direct its attention to the locations where the integrate-fire neurons are fired. Finally, the visual attention model is applied to make the robot select the visual information from the environment, and react to the content selected. Experimental results show that it is possible for robots to acquire the visual information related to their behaviors by using the attention model considering motion statuses. The robot can select its behaviors to adapt to the dynamic environment as well as to switch to another task according to the recognition results of visual attention. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(2): 39–48, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20335 more...

This paper proposes a method to estimate sound source position by fusing auditory and visual information with Bayesian network in human-robot interaction. We firstly integrate multi-channel audio signals and a depth image about the environment to generate a likelihood map for sound source localization. However, this integration, denoted by “MICs", does not always lead to locate a sound source correctly. For correcting the failure in localization, we integrate the likelihood values generated from “MICs" and the skin-color distribution in an image according to the result of classifying audio signal into speech/non-speech categories. The audio classifier is based on support vector machine(SVM) and skin-color distribution is modeled by Gaussian mixture model (GMM). With the evidences given by MICs, SVM and GMM, we infer whether pixels in images correspond to a sound source or not according to the trained Bayesian network. Finally, experimental results are presented to show the effectiveness of the proposed method. more...

Recognizing characters on signboards in a scene would be very useful for translation, aquiring relevant information through the Internet, etc. This paper presents a method for extracting characters on signboards in arbitrary scene images that does not require any manual operations. First, we describe briefly the framework of an information handling system driven by characters on signboards in scene images. Next, a method for detecting signboard regions and individual character regions is investigated in consideration of signboards characteristics. The proposed method for detecting signboard regions is based on hierarchical clustering in the L* a* b* color space. Features of contour shape are examined to narrow the candidates of signboard regions. In addition, merging of adjacent candidate regions and rough checking of character existence are performed. Finally, each character on the signboard region is extracted by using binarization followed by horizontal and vertical projections. Experimental results from applying the method to 1000 various scene images show the effectiveness of the proposed method. more...

The ability to interact with multiple users as well as to recognize the ways in which people are interacting is essential for a robot participating in society. Forming shared attention is regarded as fundamental in improving the flexibility of human-robot interaction. This paper proposes an algorithm that enables shared attention between a robot and speakers in alternative conversational situations. We firstly present a microphone array technique and a method to combine auditory and visual information for estimating the physical location of the sound source. Secondly, the speaker is detected according to the linear combination of the result of sound source localization and the likelihood map representing the distribution of pixels having skin color. Finally, in the conversational situations, the speaker's focus of attention is alternatively detected and shared by the robot for upcoming communication based on the proposed algorithm. Several experimental results are presented that demonstrate the effectiveness of the proposed method. more...

In human-robot interaction, the ability to detect and share user’s attention is the minimal requirement for an intelligent robot, since it is very important for robot to know human’s internal state. Here we present an algorithm, which is based on face posture estimation and the spatiotemporal image processing, to calculate a saliency map in order to form share attention. After the face posture estimation, we introduce an elliptic cone to approximate the user’s visual field, whose axis is fitted to the user’s gaze line that is not necessary to be detected beforehand. A visual acuity map on the user’s retina can be yielded according to the formulization of human’s visual acuity. We calculate the saliency map in terms of recency-weighted average of visual acuity maps along time axis so that the dynamic scene (for example, the case that user’s gaze line is shifting to a new object or the gazed object is moving) can affect the saliency map calculation, as well as the moving image areas are tracked to propagate the value of the visual acuity map from the current frame to the next one. Finally, we use the saliency map to form share attention in human-robot interaction, and it is also manifested that it will be possible to detect the user’s attention by only considering face orientation even when the eyes cannot be observed clearly. more...

本研究では, 高密度実装に有利なBGAパッケージに対して, はんだ接合部の信頼度に大きな影響を与えるはんだ高さ, 濡れ角などのリフロー時の形状計算手法の調査を行った。はんだ形状予測に関する数種類の方法について調査を行い, 実験結果と比較することによって各計算手法の妥当性について検討を行った。また, これらの計算手法の1つである差分法に, 直交表を用いた応答曲面法を適用することによって, はんだ高さ, 濡れ角を簡易に計算できる近似式多項式の作成を行った。次に, リフロー時のはんだ凝固時に発生する残留応力を評価するため, はんだ凝固時の基板変形を有限要素法, 実測により評価した。 more...

Generalized linear phase lapped orthogonal transforms with unequal length basis functions (GULLOTs) are considered. The length of each basis of the proposed GULLOT can be different from each other, whereas all the bases of the conventional GenLOT are of equal length. In general, for image coding application, the long basis for a low-frequency band and the short basis for a high-frequency one are desirable to reduce the blocking and the ringing artifact simultaneously. Therefore, the GULLOT is suitable especially for a subband image coding. In order to apply the GULLOT to a subband image coding, we also investigate the size-limited structure to process the finite length signal, which is important in practice. Finally, some design and image coding examples are shown to confirm the validity of the proposed GULLOT. more...

This paper proposes a method of estimating multiview camera parameters for cases in which the structure of objects is unknown. The proposed method uses multiple rectangles in the 2-D images captured with the same focal length as the keys to estimate camera parameters. In this method, the 3-D coordinates of rectangles are first estimated from all images by using the characteristic of rectangles and the least squares method. Then, all camera parameters are estimated by using the estimated 3-D coordinates of rectangles and the least squares method. Finally, all parameters, that is, 3-D coordinates of rectangles and camera parameters, are corrected to minimize the errors in all images. Experimental results show that the proposed method gives good estimations of the multiview camera parameters required to obtain ray information for cases in which the shape of objects is unknown. This means that ray information can be acquired by using one ordinary camera instead of a special camera controlled by computer. more...

In order to achieve flexible 3-D visual communication, we have proposed a light ray based describing method of 3-D images. Furthermore, we have proposed a new concept of “3-D Space Coding” to describe and transmit the entire visual data of a 3-D space. Because the amount of spatial data is huge, it must be compressed for transmission and for easy handling by computers. In order to synthesize an image from one viewpoint, it is not necessary that all of the compressed data are expanded. Only the data essential for each view should be expanded. In this paper, the concept of “3-D Space Coding” is explained and a method for expanding the compressed light ray data locally is discussed in detail. Experimental results show the potential applicability of the proposed method to deal with larger space by local expansion of compressed light ray data. more...

Video network is beginning to have various kinds of applications such as using a vertical blanking interval. Model-based coding is suitable for the narrow band network. Interactive model-based image coding, which had been developed for non-realtime environment, needs to be specified by the number and the precision of interactive operations. This paper first analyzes the noise in input feature points during the global motion parameter detection. Then a new structure filter for reducing the noise in the feature points on a facial wireframe model is developed. The structure filter keeps original facial shape composed of feature points and reduces variation in the mutual distance between the feature points. In evaluating the precision for applying the least-squares method for detecting depth and global motion parameters, the number of conditions of input data is considered from the point of variance of error of the estimated values. Based on the structure filter with the precision evaluation, the allowance error in the interactive operation for the encoding process is specified by the pixel accuracy for feature point position. more...

あらまし3次元空間における膨大な光線情報に対して, 1台のカメラの位置を逐次的に制御しながら光線情報を効率的にサンプリングする手法を提案する.すでに取得された光線情報から3次元空間がどの程度正確に補間合成され得るかを予測し, 補間が困難な視点位置から優先的に光線情報を取得する.実際に視点探索の実験を行い、本手法の実現可能性を示す.

First, this paper introduces the concept of “Integrated 3-D Visual Communication”. The key feature in this concept is the display-independent neutrality and flexibility of the representation of visual data. Secondly, a ray-based approach is examined in order to realize this concept. The advantage of a ray-based approach is that any view can be synthesized from ray data independently of any geometric representations. All the visual data is represented by a set of ray data which is defined in five-dimensional data space. Assuming that rays go straight on without any variations in the direction of propagation, any individual ray data can be efficiently stored in the fewer dimensions. This paper proposes and formulates three methods for projecting five-dimensional data space onto a space with fewer dimensions. The experimental results show how the proposed methods could be used in the next-generation 3-D image communication and photo-realistic virtual reality systems. more...

This paper proposes a new method of describing spatiotemporal images based on the concept of structured abstract index images. In spatiotemporal images, each region in an image sequence forms a tube. An original image sequence can be reconstructed by cutting out the sequence of cross sections from the group of tubes in these images. That is, a moving image sequence can be described compactly by the group of tubes. This paper first discusses the method of approximating static contours by Bezier curves. Approximation of surface tubes by Bezier surface is examined in detail. A problem with this method is that it does not work well if shape of the cross section changes considerably along the time axis. This problem can be solved by growing a new Bezier surface from passing points of Bezier curve and by combining the different Bezier surfaces. more...

A ray-based method has been proposed as a neutral description method for various kinds of 3-D images. In this paper, we propose a new method for converting a set of range and color data of 3-D objects obtained by a range finder into ray data. This method enables us to handle range data in the same manner as other kinds of 3-D images and to use conventional image processing techniques to improve the quality of reconstructed images. Furthermore, to compensate for the missing of range data caused by some restrictions inherent to a range finder, we examine the ray-based merging method of multiple sets of range and color data of the same object, which are obtained under different conditions. Experimental results show the usefulness of the proposed method to facilitate a range finder as an input device of 3-D information in an integrated 3-D communication system. more...

Reconstruction of virtual space has become very important in various applications. Computer graphics methods based on geometric models have been studied for this purpose. To obtain more natural representation, this paper proposes a new method which represents and handles 3 D objects using the concept of “ray space.” Ray space is a space that stores the rays reflected by 3 D objects. Handling objects in real space is equivalent to getting a sliced image with an appropriate plane in the ray space. more...

In this paper, we propose a new framework of representing 3-D spacial information by using 'Rays'. We show that this data format includes all the information of the scene viewed from any direction, so that, one view image from an arbitrary viewpoint can be obtained by sampling ray data. We also introduce ray parameter space and examine its characteristics. We give a new definition of visual field and viewing zone and evaluate the amount of ray data in terms of ray parameter space. In addition, we show possible applications of this concept by presenting simulations, including generating an any-viewpoint image and a variable-focused image, synthesizing a real image and a computer-generated image, and compressing a hologram pattern. more...

知的画像情報処理には, 知識に基づく (知識を利用した) 画像情報処理と, 画像の意味内容に立ち入った画像情報処理という2通りの意味合いを考えることができる.画像理解の分野では, 3次元シーンの理解において, 対象や処理手法に関する知識の利用がいろいろと検討されてきた.一方, 画像理解とは異なる観点から, 画像通信・符号化や画像の編集・操作の分野を中心にして知的な処理要素の導入が進み, 新たな展開が活発になってきている.本稿では, まず知的画像情報処理の中で重要な役割を果たす画像情報の構造化について述べる.次に, 画像通信・符号化, 映像の編集・操作の分野における知的処理の基本的な考え方および研究動向について解説する. more...

本論文では, 対象物の3次元的な動きに着目した動き補償予測符号化方式を提案する.シミュレーション実験を行い, 従来のブロックマッチングによる動き補償予測符号化に比べて本提案方式が復号画像の画質の改善に有効な方式であることを示す.