Autonomous fetal ultrasonography with a robotic ultrasound (US) can potentially solve the issue of the shortage of ob-gyn physicians in prenatal care. In fetal cardiac diagnosis, acoustic shading derived from the fetal skeleton makes the scanning procedure using a robotic US cumbersome. We hypothesize that fetal bone distribution can be used for determining the fetal position and for subsequently estimating the heart position. This paper serves a method for estimating fetal heart position for autonomous cardiac diagnosis. Our proposed system is comprised of following three processes. First, the fetal bone distribution is generated by following steps: detect shadow areas derived from fetal bones; calculate the three-dimensional (3D) position of the bones; and identify bone types (skull, spine, and others) based on its shadow features. Next, the fetal head position and body axis are estimated based on the generated 3D bone distribution. Finally, the fetal chest position and thoracic sagittal axis of the fetus are estimated based on anatomical structures, and the position of the heart is determined. We validated the proposed method by evaluating the accuracies of bone detection and heart position estimation with three pregnant volunteers. The false positive rate of bone detection is less than 10%, which is sufficient for the proposed method; further, the estimation error for the heart position was within an acceptable error of 15 mm. These results demonstrate the sufficient accuracy of the proposed estimation method and suggest the potential of autonomous fetal cardiac diagnosis using robotic US scanning.

In case of dramatic means of communication such as an improvised drama, it is well-known that the existence and function of audiences are key to the endurance of a creative story. In order to achieve this dramatic communication between remote locations, this study aimed to design and develop a theater-type coexisting space in which drama players (actors) can be positioned while being accompanied by empathetic audiences. To this end, the Waseda Shadow Communication System (WSCS) was applied; it was previously developed by the present authors to create a feeling of coexistence that could be shared with remotely located people through the exchange of body shadows. Communication space in WSCS was divided into two components with a transparent screen and a shoji (Japanese paper) screen; to each screen, shadows of drama players and audiences were projected separately. The relative relationship of each position was matched and expressed, so that a theater-type communication system was established, which comprised audiences, drama players, and their mutual stage. The shadow expression method was further investigated for audiences freely entering and exiting the theater.

Many shared-space communication systems have been proposed which support bodily actions, such as eye gaze and instruction, among remote people. However, the method to share a three-dimensional bodily action in physical space with remote people has not been explored sufficiently. In this paper, we propose a novel method of a shared-space communication to support to bridge over remote two tabletops visually and to share bodily action among remote people. To achieve this aim, a video image of remote tabletop is required to be shared with each other. A display and an interface are also needed for reflecting a remote bodily action in a local space consistently. Consequently, the front screen, on which a video image of a remote space including a tabletop is projected to connect tableside visually, is installed aslope on a table. We developed also a Virtual Extensible Tool Interface which supports visual interactions including pointing to and touching a physical object in remote space by representing virtual extensive tool to a remote space. Experiments on bodily interactions between local and remote people demonstrated that the extensible tool interface can support bodily interactions with a remote partner including instructing to a remote physical object in three dimensions. Moreover, the results indicate clearly that the participants felt as if they were touching the remote table. Thus, our system possesses a potential to support a remote co-creative communication including a physical interaction through tools, and it is promising.