Haptic rendering is a process that provides force feedback during interactions between a user and a virtual object. This study proposes real-time haptic rendering of a deformable object based on visual information for telemanipulation. When a manipulator (slave) controlled by a haptic device (master) exerts manipulation tasks on a remote deformable object in a real environment, a user can feel the reaction force in real-time. The force feedback is provided in image coordinates from a captured

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... age obtained through a CCD camera, and the recognition of deformable object and manipulator in images is achieved using image-processing techniques. The reaction force is deduced at a rate of 1 kHz from forces computed at a low frequency for stable interaction with the model. Data Extraction To extract the coordinate information from the images, an image-processing algorithm is run in real-time. This algorithm consists of two parts: manipulator segmentation and deformable object extraction (Fig. 1) . First, template matching [1] is used to recognize the manipulator. A marker is attached at the manipulator tip and is considered as a template. Correlation between the template pixel and every pixel in the entire image is then computed; the maximum correlation value is the matching point at the position of the manipulator tip. Finally, an edge detection technique known as a snakes algorithm [2] is carried out to obtain the position and the shape of the deformable body. In this procedure, a contour with nodes is arbitrarily defined. The pixel energy is computed around the nodes, and the contour is then laid on the edge of the object where the energy has the local minimum value. Figure 1. Image processing: original image (left), correlation image (center) and snakes contour (right)