Takeyoshi Dohi

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In this paper, a level-set-based geometric regularization method is proposed which has the ability to estimate the local orientation of the evolving front and utilize it as shape induced information for anisotropic propagation. We show that preserving anisotropic fronts can improve elongations of the extracted structures, while minimizing the risk of(More)
Recent typical therapy for twin-to-twin transfusion syndrome (TTTS) is selective laser photocoagulation of anastomotic communicating vessels on the placenta using the fetoscopic approach. The difficulty of a conventional laser device approach for this procedure depends significantly on the placental location, so a new robotized device is required to bend(More)
A 3-D augmented reality navigation system using autostereoscopic images was developed for MRI-guided surgery. The 3-D images are created by employing an animated autostereoscopic image, integral videography (IV), which provides geometrically accurate 3-D spatial images and reproduces motion parallax without using any supplementary eyeglasses or tracking(More)
This paper describes an autostereoscopic image overlay technique that is integrated into a surgical navigation system to superimpose a real three-dimensional (3-D) image onto the patient via a half-silvered mirror. The images are created by employing a modified version of integral videography (IV), which is an animated extension of integral photography. IV(More)
A method by which to register multimodality medical images accommodating soft tissue deformation is presented in the context of interventional therapy with a MR scanner. Accuracy testing with arbitrarily deformed MR images and application studies of a pig's brain were undertaken to evaluate the feasibility of the method. When Mutual Information is employed(More)
THREE-DIMENSIONAL reconstructions of medical images are widely used. Although there are several established techniques, if the purpose of reconstruction is only visualisation, volume rendering is the best way (CHRISTIAN, 1993). However, in applications such as surgical support, visualisation is insufficient and a more interactive approach is required.(More)
Many problems in laparoscopic surgery are due to the poor degrees of freedom of movement (DOF) in controlling forceps and laparoscopes. The Multi-DOF forceps manipulator we have newly developed has two additional DOF of bending on the tip of forceps, and provides new surgical fields and techniques for surgeons. The most remarkable characteristics of the(More)