The Journal of The Institute of Image Information and Television Engineers

We propose a method to realize mouse functions using a laser pointer. A function to automatically move the mouse cursor to laser spots on a screen was realized. Restrictions on illumination environment were overcome using a frequency-demodulation image sensor. Laser spots were successfully detected at a luminance as high as several thousands lx. Methods to detect spots and transmit information, such as a mouse click without using a synchronous signal, were proposed and then verified by experiments. Such asynchronous operations make a signal line to a laser pointer unnecessary. Identifying a laser pointer among a plural number of laser pointers is also possible. The proposed system realizes smoother operability in presentations as well as some human-computer interaction applications.

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This research proposes a method of representing objects for a 3D display device that uses a pulse laser and generates plasma luminous bodies in arbitrary positions in midair. By using a xyz-scanner, the device controls the position of plasma luminous bodies that appear and disappear one by one in 1 kHz. The device can display an object in one stroke in midair. We propose our method of representing primitive objects— polygons, polyhedrons and curved surface objects— in consideration of hardware limitations and human visual characteristics, and evaluate the objects in experiments. As a result, polygons can be represented visually, effectively reducing the scanner burden by smoothing accelerations at corners and increasing the plasma density; polyhedron faces are best drawn one by one; and when curved surface objects are drawn using spiral, we can stably perceive them.

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Interactive mesh editing techniques are commonly used for creating a new mesh model by deforming existing mesh models. In surface-based deformation, geometric shapes are encoded using differential equations, and they are deformed so that the equations and other constraints are satisfied in a least-squares sense. Although constraints are typically approximated as linear equations, constraints that preserve volume require nonlinear equations. In such cases, it is time-consuming to solve the nonlinear equations. In our method, we enclose a mesh model with multiple overlapping lattices so that a subset of vertices is shared by two or more lattices. Then, the vertex coordinates in equations are replaced by the coordinates of the lattices. Vertices shared by multiple lattices are used to propagate deformation between disconnected lattices. Our method makes it possible to efficiently solve non-linear equations and interactively deform mesh models while preserving the volume of mesh models.

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Interactive mesh deformation is a powerful tool to create new mesh models from existing mesh models. When a mesh model is deformed, it is very important to preserve visually distinct features. However, existing deformation methods, which typically maintain discrete mean curvature, fail to preserve such visually distinct features. This is because mean curvature is calculated using just one- or two-ring vertices, although geometric features can be represented in various scales of mesh regions. In our method, the shapes of features are constrained based on visual saliency, which is calculated using a weighted sum of various resolutions of mean curvature values. We introduce a new constraint that can control the stiffness of a feature region based on the value of visual saliency. Such constraints are effective to realize interactive deformation that adequately preserves visually distinct features. We show that our method can interactively deform mesh models while preserving the visual saliency of mesh models.

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