著者
倉重 光宏
出版者
一般社団法人 映像情報メディア学会
雑誌
テレビジョン学会誌 (ISSN:03866831)
巻号頁・発行日
vol.37, no.5, pp.401-407, 1983-05-20 (Released:2011-03-14)
参考文献数
9

本論文は, 低速度のビームランディングに固有のセルフシャープニング効果が撮像管の解像度決定にどう寄与するかを明らかにすることを目的として, 同効果を支配する代表的な3つのパラメーターである, ターゲット蓄積容量, 信号電流, 走査線ピッチを選び, その影響を実測, および筆者が確立した解析理論により検討したものである. その結果, (i) セルフシャープニング効果は上述した3つのパラメーターに顕著に依存し, 例えば代表的な撮像管の設計に見られる蓄積容量数千pFのターゲットに対して数十%の解像度改善をもたらすこと, (ii) しかし, 本効果は蓄積容量が3000pF以上の場合や信号電流が数10nA以下では消滅すること, また (iii) 走査線本数を適度に増やすと本効果によって垂直解像度が顕著に改善されることなどが実測, 理論とも一致した結論として得られ, 今後の撮像管設計や撮像管の使いこなしに必須の貴重な指針が得られた.
著者
渡邊 紀文 森 文彦 大森 隆司
出版者
一般社団法人 映像情報メディア学会
雑誌
映像情報メディア学会誌 (ISSN:13426907)
巻号頁・発行日
vol.67, no.12, pp.J434-J440, 2013 (Released:2013-11-25)
参考文献数
12
被引用文献数
2

In daily life, our behavior is guided by various visual stimuli such as the information on direction signs. However, our environmentally based perceptual capacity is often challenged in crowded circumstances, or more so, in emergency evacuation circumstances. In these situations, we often fail to pay attention to important signs. In order to achieve more effective direction guidance, we considered the use of unconscious reflexes in human walking action. In this study, we experimented with vision-guided walking direction control by optic flow stimulus combined with body sway. We observed a shift in subjects' walking direction and body sway and discuss the possible mechanism.
著者
三功 浩嗣 内藤 整
出版者
一般社団法人 映像情報メディア学会
雑誌
映像情報メディア学会誌 (ISSN:13426907)
巻号頁・発行日
vol.68, no.3, pp.J125-J134, 2014 (Released:2014-02-25)
参考文献数
12
被引用文献数
2 5

In this paper, we propose a robust object tracking scheme for multi-view cameras and consecutive frames for rendering an immersive free-viewpoint video in a large outdoor space such as a soccer stadium. For a free-viewpoint video that provides users with an immersive experience, each object has to be identified consistently among all cameras for every frame to share the textures of the same objects and replace the textures when an occlusion occurs. To satisfy this requirement, the proposed method extracts objects' silhouette regions and tracks each identified object by associating a closed silhouette region with a tracking ID for every camera. During the frame by frame process, our method confirms whether occlusion occurs for each tracking region and modifies the texture region by projecting the world coordinate of the object in 3D-space, which can be estimated from a camera image without occlusion if one is available. The experimental results revealed that the proposed method achieved more robust texture extraction of multiple objects especially for occluded regions compared to the conventional methods. Furthermore, it was confirmed that the proposed scheme can improve the subjective image quality for free-viewpoint video as a result of precise reconstruction of occluded regions.
著者
松久 ひとみ 橋本 学
出版者
一般社団法人 映像情報メディア学会
雑誌
映像情報メディア学会誌 (ISSN:13426907)
巻号頁・発行日
vol.68, no.6, pp.J252-J255, 2014 (Released:2014-05-23)
参考文献数
10
被引用文献数
3

Identifying subtle human facial expressions is important in human interactions such as human-robot communications. We propose a method to classify two types of facial expression, neutral (expressionless) and the subtle expression of happiness, using an image acquired with a camera. In the proposed method, facial shape features such as wrinkle-angle or unevenness of face surface are extracted via Gabor filters in multiple ROIs on a human face. High angle resolution Gabor filters are used to detect subtle facial expressions and the positions of the detection window and Gabor filter parameters are optimized by a learning process using AdaBoost. Changes to facial expression are estimated by comparing an input image to a learned database with the features. Experimental results showed that the proposed system has a 0.84 precision rate and a 0.91 recall rate in the case of detecting subtle changes.
著者
山川 大貴 福元 清剛 海老澤 嘉伸
出版者
一般社団法人 映像情報メディア学会
雑誌
映像情報メディア学会誌 (ISSN:13426907)
巻号頁・発行日
vol.68, no.6, pp.J232-J237, 2014 (Released:2014-05-23)
参考文献数
18

It is difficult for gaze detection systems to detect pupils in camera images containing eyeglasses reflections caused by the infrared light sources necessary for gaze detection. In a previous study with a system using two cameras, we proposed a geometrical pupil detection algorithm. However, depending on the positional relationship between the pupil and the reflection, the algorithm was not always effective. In the present study, we arranged three cameras—one at each vertex of a triangle—and composed three camera pairs with different base line directions. We propose several new algorisms, and in the basic algorithm, pupil candidates indicating the suprathreshold angle between two planes, each of which includes the cameras composing a camera pair and the candidate detected by one of the two cameras, are removed from the candidate list. A significant improvement of pupil detection is experimentally demonstrated.
著者
池田 拓也 小山田 雄仁 杉本 麻樹 斎藤 英雄
出版者
一般社団法人 映像情報メディア学会
雑誌
映像情報メディア学会誌 (ISSN:13426907)
巻号頁・発行日
vol.67, no.4, pp.J124-J133, 2013 (Released:2013-03-25)
参考文献数
13

Optical consistency between the real world and virtual objects is an important issue in augmented reality (AR). We propose a method to estimate illumination from an object shadow and incomplete object shape information captured by an RGB-D camera. The environmental illumination can be estimated without any prior knowledge of the object shape. The radiance of each light source is computed by solving linear equations derived from color and depth images. Since prior knowledge of the object shape is not necessary, we can flexibly use/combine any objects. Thus, we can use/combine multiple objects in the target scene to increase the accuracy and flexibility. Our experimental results show the characteristics of our proposed method.
著者
宮里 勉
出版者
一般社団法人 映像情報メディア学会
雑誌
映像情報メディア学会誌 (ISSN:13426907)
巻号頁・発行日
vol.67, no.9, pp.J352-J355, 2013 (Released:2013-08-23)
参考文献数
20

We propose a new mobility support device that helps the visually impaired person to avoid colliding with objects in his/her path. The device uses auditory localization of a sound source generated by ultrasonic phased array. The acoustic image is emitted at the real position of the obstacle, so the distance and direction to the obstacle are recognized by the usual auditory lateralization ability of the user. Therefore, using our device needs no special training over a long period of time, which is an advantage over using the white cane and the conventional so-called electronic white cane.
著者
真野 航 齋藤 豪
出版者
一般社団法人 映像情報メディア学会
雑誌
映像情報メディア学会技術報告 (ISSN:13426893)
巻号頁・発行日
vol.37, pp.25-28, 2013

セルアニメーションにおけるキャラクタは、非現実的な動作や変化といった現実の人間とは異なった描画のされ方をしている。しかし、その描画は視聴者に大きな違和感を与えない場合が多い。すなわち、ただ単純に3DCGモデルを画面に投影したものとは異なるが、見る者に違和感を与えないような描画のされ方をしている。本稿ではキャラクタの振り向き動作時の顔の描画の分析をするために作成した、フレーム毎に顔の各要素の特徴点位置を記録するプログラムについての報告と、要素間の距離変化の分析の報告を行う。
著者
森本 雅和 金子 弘樹 宮本 直樹
出版者
一般社団法人 映像情報メディア学会
雑誌
映像情報メディア学会誌 (ISSN:13426907)
巻号頁・発行日
vol.68, no.1, pp.J47-J54, 2014 (Released:2013-12-20)
参考文献数
7
被引用文献数
1

A method is described that can estimate vehicle speed from video footage taken by an in-vehicle monocular camera. The method involves applying structural information and feature points to a road surface and analyzing their passage over time to accurately estimate pilot-vehicle and oncoming-vehicle speed. Experimental results demonstrated that our method estimates the speed of pilot and other moving vehicles with enough accuracy to investigate traffic accidents.
著者
長谷川 尭史 小川 貴弘 渡邉 日出海 長谷山 美紀
出版者
一般社団法人 映像情報メディア学会
雑誌
映像情報メディア学会誌 (ISSN:13426907)
巻号頁・発行日
vol.66, no.7, pp.J240-J250, 2012 (Released:2012-06-25)
参考文献数
15

This paper presents a support vector data description (SVDD)-based method for finding new benthic species from microscopic images and its application to taxonomy position estimation. First, the proposed method generates hyperspheres that represent taxonomic species taxa of known species and enables automatic species classification. Furthermore, weight estimation of visual features based on multiple kernel learning (MKL) is used in this approach to realize automatic weighting of categorical traits that are traditionally determined by taxonomists. Next, based on the traditional taxonomic classification scheme, the proposed method merges the hyperspheres of similar species and generates new hyperspheres that represent ultra-species taxa in higher hierarchies. Then, from the obtained results, a new decision tree, whose nodes are hyperspheres of species taxa and ultra-species taxa, is constructed. By using this decision tree, new benthic species can be found from target samples, and their taxonomic positions can also be estimated.