SIGGRAPH Asia 2022 Papers

We realized color animation of a computer-generated hologram (CGH) while retaining the features of the conventional full-parallax high-definition CGH (FPHD-CGH) method such as large screen size and a wide viewing area. Since the FPHD-CGH is fabricated using a laser direct writing system, the only way to animate it is to switch structured illumination (SI), and even that method has the problem of overlapping images from different frames caused by light leakage. We propose a method of suppressing this light leakage while maintaining image quality by applying erosion to SI. We also developed the world’s first two-frame color animation prototype, which is 18 cm square and has a 30-degree viewing angle horizontally and vertically. We did this by combining our method with the existing FPHD-CGH colorization method.

This work introduces a novel method for automating the object animation from a 3D mesh used in various applications such as AR/VR, gaming, etc. The 3D mesh could be a generic inflated object generated from an image or sketch. The method describes a medial axis based control point estimation to generate an animation path and perform deformation-based animations for a mesh. Our method eliminates user involvement or need for expertise in terms of rigging the mesh or region selection etc. Performance of our method shows meaningful, real-time animation of the 3D mesh. Experiments indicate that our method is more consistent and less error prone compared to existing works.

This paper presents a procedural modeling method for coral groups considering the territorial conflict between species. We developed a graphical interface to control the territorial battle by arranging locator points that represent available space to grow the coral branches. The coral skeletals are generated according to species-specific structural rules while competing for the locators between individuals.

In 3D character animation, the frame rate is often reduced to mimic hand-drawn animations, like anime (Japanese animation). However, anime with a low frame rate differs from real motions because it omits excessive movements and emphasizes speed by expressing motions with a small number of impressive poses. It is difficult to reproduce such motions only by downsampling mocap data. Thus, in this poster, we propose a method for converting mocap data into anime-like 2D motions by respecting production site techniques. The proposed method evaluates the characteristics of motion data using the time distributions of speeds and pose areas to select an appropriate sequence of viewpoints and extract effective poses for each viewpoint.

Recently, many image stylization techniques have been proposed to convert photographs into illustrations, paintings, cartoons, etc. Artists sometimes use these techniques to efficiently generate background images for their own illustrations of foreground objects, such as cartoon characters. However, this approach often produces unnatural results because the level of abstraction between the foreground and the background images are different, resulting in inconsistent atmosphere between them. In this paper, we address this problem and propose a method for adjusting the abstraction level of the stylized background images. The effectiveness of our method is demonstrated by several examples with different levels of abstraction.

Real-time visualization of large-scale surface models is still a challenging problem. When using multiple levels of details (LOD), the main issues are popping between levels and/or cracks between level parts. We present a scheme (both mesh preprocessing and real-time rendering), which avoids both of these issues. Vertex interpolation between child and parent is used to achieve crack and popping free rendering. We implemented and tested our method on a modest laptop PC, and could render scanned models of multiples tens of million triangles at optimal visual quality and interactive frame rate.

Large, high-resolution displays are installed throughout the city as public displays. By superimposing invisible information on the images of these displays, large numbers of devices with cameras and sensors can communicate with the displays without prior pairing. Several applications have been proposed, such as operating robots or communicating information to users by displaying 2D codes on images. However, the display of 2D codes has the problem of compromising the appearance of displayed content. Abe et al. proposed a method of communicating with devices by superimposing invisible information using color vibration on images displayed on off-the-shelf liquid-crystal displays (LCD). Using this method, we can embed the information for devices in images without interfering with the displayed content. Abe et al. uses a simple serial loop operation to search for color pairs comprising a color vibration, which requires a very long processing time due to the huge search space. In this paper, we propose an accelerated and optimized search method for color pairs that constitute the imperceptible color vibration for embedding information on LCD images. To achieve fast color pair search, we parallelized the search process, which is previously done individually, by using arrays representing the amount of movement and an operation to extract elements from the array that satisfy the conditions. In addition, we investigate the amount of information that can be superimposed on nine color images using the imperceptible color vibration and clarify the applicability of embedding information into images using the color vibration.

We address the problem of controlling and simulating interactions between multiple physics-based characters, using short unlabeled motion clips. We propose Adversarial Interaction Priors (AIP), a multi-agents generative adversarial imitation learning (MAGAIL) approach, which extends recent deep reinforcement learning (RL) works aiming at imitating single character example motions. The main contribution of this work is to extend the idea of motion imitation of a single character to interaction imitation between multiple characters. Our method uses a control policy for each character to imitate interactive behaviors provided by short example motion clips, and associates a discriminator for each character, which is trained on actor-specific interactive motion clips. The discriminator returns interaction rewards that measure the similarity between generated behaviors and demonstrated ones in the reference motion clips. The policies and discriminators are trained in a multi-agent adversarial reinforcement learning procedure, to improve the quality of the behaviors generated by each agent. The initial results show the effectiveness of our method on the interactive task of shadowboxing between two fighters.

People with visual impairment (PVI) are eager to push their limits in extreme sports such as alpine skiing. However, training skiing is very difficult as it always requires assistance from an experienced guide. This paper explores sonification-based methods that enable PVI to train skiing using a simulator, which will allow them to train without a guide. Two types of sonification feedback for PVI are proposed and studied in our experiment. The results suggest that users without any visual information can also pass through over 80% of the poles compared to with visual information on average.

Preoperative models manufactured by 3D printing technology are widely demanded in surgical procedures. Current printing methods such as Polyjet, color jet printing (CJP) and fused deposition molding (FDM) are either too expensive or of poor performance. In this paper, a novel solution is proposed. Preoperative models are first divided into internal part, such as blood vessel, and the main body. The former is printed in color and the latter is transparent. In particular, the internal part is printed using FDM. A housing template for the main body is generated by digital light processing (DLP) based on the preoperative model. After integrating the template and inner part, transparent elastomer precursor is injected and cured inside the template, leading to the formation of the transparent main body. For demonstration, a liver model is manufactured using the proposed scheme. Compared with the existing methods, our strategy could manufacture preoperative models at both high quality and affordable cost.

Soil structure describes the association and arrangement of the soil granules. Structured clays, such as the cracked dry ground, exhibit characteristics of solid-like materials, while destructured clays exhibit characteristics of granular materials. The structure strength weakens with the deviatoric plastic strain accumulation, which leads to clay degradation. However, the existing graphics methods for granular materials cannot simulate this unique mechanical behavior. We present a non-associated Modified Structured Cam Clay (MSCC) model for simulating structured and destructured clays. We track the deviatoric part of the plastic Hencky strain and design two degradation functions (corresponding to yield stress and mean effective stress) to control the size of the yield surface. Through a non-associated flow rule, our method generates visually plausible results while allowing volume preservation.

In this work, we present a high frame rate affordable nystagmus detection aid for outpatient clinic use. Using a Frenzel goggles and the high-speed video recording feature of a smartphone, high-frame rate eye videos of patients are obtained. Then, OpenCV morphological operation and blob detection library were modified to manually adjust the parameters according to the video to capture and track the eye center movements. Next, we correct the error caused by hand shaking during photography and predict the eyeball movement during blinking. Finally, with rule-based detecting method, nystagmus was detected and classified based on the modified tracking data. In our experimental, we collaborated with a professional ENT doctor to obtain multiple high-frame rate eye videos of patients. Experimental results show that this procedure can provide preliminary diagnosis results for physicians to refer to, but the final diagnosis needs to be made by a professional ophthalmologist. Plus, this method has been used by the ENT doctor to record the result simultaneously.