Kazuhiro Hiwada

Realistic animation of fluid with splash and foam

In this paper we describe a method for modeling and rendering dynamic behavior of fluids withsplashes and foam. A particle system is built into a fluid simulation system to represent an ocean wavecresting and spraying over another object. We use the Cubic Interpolated Propagation (CIP) method asthe fluid solver. The CIP method can solve liquid and gas together in the framework of fluid dynamicsand has high accuracy in the case of relatively coarse grids. This enables us to simulate the fluids in ashort time and describe the motion of splashes in the air that is associated with the liquid motion well.The foam floating on the water also can be described using the particle system. We integrate the rigidbody simulation with the fluid and particle system to create sophisticated scenes including splashes andfoam. We construct state change rules that are used with the particle system. This controls the generation,vanishing and transition rule of splashes and foam. The transition rule makes the seamless connection betweena splash and foam. We employed a fast volume rendering method with scattering effect for particles.One of the important features of our method is the combination of fast simulation and rendering techniques,which provides dynamic and realistic scenes in a short time.

Switchable primaries using shiftable layers of color filter arrays

We present a camera with switchable primaries using shiftable layers of color filter arrays (CFAs). By layering a pair of CMY CFAs in this novel manner we can switch between multiple sets of color primaries (namely RGB, CMY and RGBCY) in the same camera. In contrast to fixed color primaries (e.g. RGB or CMY), which cannot provide optimal image quality for all scene conditions, our camera with switchable primaries provides optimal color fidelity and signal to noise ratio for multiple scene conditions. Next, we show that the same concept can be used to layer two RGB CFAs to design a camera with switchable low dynamic range (LDR) and high dynamic range (HDR) modes. Further, we show that such layering can be generalized as a constrained satisfaction problem (CSP) allowing to constrain a large number of parameters (e.g. different operational modes, amount and direction of the shifts, placement of the primaries in the CFA) to provide an optimal solution. We investigate practical design options for shiftable layering of the CFAs. We demonstrate these by building prototype cameras for both switchable primaries and switchable LDR/HDR modes. To the best of our knowledge, we present, for the first time, the concept of shiftable layers of CFAs that provides a new degree of freedom in photography where multiple operational modes are available to the user in a single camera for optimizing the picture quality based on the nature of the scene geometry, color and illumination.

Fast simulation and rendering techniques for fluid objects

Movies with actions and light effects of fluid objects are aesthetically pleasing and interesting. Until now, the calculation costs of simulation and rendering of fluid objects have been very high. Using a modern PC system and appropriate methods, we achieved a time of 10‐20 seconds per frame for this application. Our system uses a full Navier‐Stokes equation solver with uniform Eulerian mesh, marching cube isosurface techniques, Catmull‐Clark subdivision surface techniques, ray tracing techniques on each vertex and conventional polygon base rendering by HW accelerator. In this paper, we describe the components of our system and the reasons for choosing them. By measuring CPU times of each process for some movie scenes of fluid objects, we evaluate this system. We consider what factors are important for creating movies of fluid objects with short TAT.

Mimicking video: real-time morphable 3D model fitting

This paper presents a new automatic scheme for tracking a 3D non-rigid object surface such as a human face in a real-time video sequence. We introduce a coordinate-oriented error minimization method for estimating the tracking parameters, whereas we base our algorithm on a morphable 3D model consisting of a combination of 3D linear bases, and show that it is extremely well suited to the task of fitting the 3D model to the target object in real time. The algorithm is straightforward, allowing the parameters of an objects pose and non-rigid motion to be computed in an integrated manner. Also, it is found that the illumination variability on the object surface, for instance due to the target motion, can be handled easily. Through the experiments we not only show that on-line tracking is indeed possible, but also demonstrate the effect of our technique of video mimicking.

A 1.4Mpixel CMOS image sensor with multiple row-rescan based data sampling for optical camera communication

A 1.4Mpixel CMOS image sensor (CIS) with multiple row-rescan (MRR) based data sampling for optical camera communication (OCC) is presented. The CIS achieves a data sampling rate at a row-scan rate of 51kS/s even with a frame rate of 30fps, a pixel size of 2.2mm × 2.2mm by multiply rescanning the rows at a modulated LED spot. The detectable minimum LED size projected onto the CIS becomes 13.2mm × 13.2mm. The MRR could be a practical solution for IEEE 802.15.SG7a OCC.