Visualizing color term differences based on images from the web

AbstractColor terms are used to express light spectrum characteristics captured by human vision, and color naming across languages partition color spaces differently. Such partition differences have been surveyed through several empirical experiments that employ Munsell color chips. We propose a novel visualization method for color terms based on thousands of images collected from query results provided by an image search engines such as Google. A series of experiments was conducted using eight basic color terms in seven languages. Pixel values in the images are counted to form color histograms according to the color pallet used in the world color survey. The visualization results can be summarized as follows: (1) Japanese and Korean color terms have wider distributions in the color space than terms in other languages do and (2) color visualizations for color terms pink and brown are affected by their links to proper nouns

Quad Pillars and Delta Pillars: Algorithms for Converting Dexel Models to Polyhedral Models

In the geometric simulation of multi-axis milling, a dexel representation solid model is frequently used. In this modeling method, the object shape is defined as a collection of vertical segments (dexels) based on a two-dimensional regular square grid in the XY plane. In this paper, the authors propose the quad pillars algorithm and its enhanced version named the delta pillars algorithm for converting a dexel model to an equivalent polyhedral stereolithography (STL) model. These algorithms define a series of vertical pillar shapes for each square cell of the grid to represent the object shape as a bundle of pillars. The final polyhedral model is obtained by performing a simplified Boolean union operation of the pillar shapes. Unlike prior methods, the proposed algorithms are simple and fast and are guaranteed to generate a watertight polyhedral model without holes, gaps, or T-junctions. An experimental system is implemented and conversion tests are performed. The system converted a dexel model based on a high-resolution grid to a polyhedral model in a practical amount of time

Visualizing sphere-contacting areas on automobile parts for ECE inspection

To satisfy safety regulations of Economic Commission for Europe (ECE), the surface regions of automobile parts must have a sufficient degree of roundness if there is any chance that they could contact a sphere of 50.0 mm radius (exterior parts) or 82.5 mm radius (interior parts). In this paper, a new offset-based method is developed to automatically detect the possible sphere-contacting shape of such parts. A polyhedral model that precisely approximates the part shape is given as input, and the offset shape of the model is obtained as the Boolean union of the expanded shapes of all surface triangles. We adopt a triple-dexel representation of the 3D model to enable stable and precise Boolean union computations. To accelerate the dexel operations in these Boolean computations, a new parallel processing method with a pseudo-list structure and axis-aligned bounding box is developed. The possible sphere-contacting shape of the part surface is then extracted from the offset shape as a set of points or a set of polygons

Automatic detection of the optimal ejecting direction based on a discrete Gauss map

In this paper, the authors propose a system for assisting mold designers of plastic parts. With a CAD model of a part, the system automatically determines the optimal ejecting direction of the part with minimum undercuts. Since plastic parts are generally very thin, many rib features are placed on the inner side of the part to give sufficient structural strength. Our system extracts the rib features from the CAD model of the part, and determines the possible ejecting directions based on the geometric properties of the features. The system then selects the optimal direction with minimum undercuts. Possible ejecting directions are represented as discrete points on a Gauss map. Our new point distribution method for the Gauss map is based on the concept of the architectural geodesic dome. A hierarchical structure is also introduced in the point distribution, with a higher level “rough” Gauss map with rather sparse point distribution and another lower level “fine” Gauss map with much denser point distribution. A system is implemented and computational experiments are performed. Our system requires less than 10 seconds to determine the optimal ejecting direction of a CAD model with more than 1 million polygons

Extraction of sliding collision area of knee-form for automobile safety inspections

The United Nations Economic Commission for Europe defines a safety regulation based on the possible collision between the driver’s knee and an automobile’s interior parts. The “knee-form” apparatus is used to evaluate compliance with this regulation. Current software for analyzing possible collisions of the knee-form is not applicable to the part whose surface is vertical and near parallel to the knee-form approaching direction. In this paper, we propose a novel algorithm named “push-and-slide” for extracting the knee-form colliding area on the console part and door panel. In the first step of the algorithm, the target surface of the part is transformed to gridlike points in a high resolution. The knee-form models in various positions and orientations are prepared in the second step. Each knee-form model is pushed to the grid-like points. The model is then moved along the part surface to detect possible collisions between the knee-form and the grid-like points. An experimental system is developed and some computational experiments are performed

Thickness and clearance visualization based on distance field of 3D objects

This paper proposes a novel method for visualizing the thickness and clearance of 3D objects in a polyhedral representation. The proposed method uses the distance field of the objects in the visualization. A parallel algorithm is developed for constructing the distance field of polyhedral objects using the GPU. The distance between a voxel and the surface polygons of the model is computed many times in the distance field construction. Similar sets of polygons are usually selected as close polygons for close voxels. By using this spatial coherence, a parallel algorithm is designed to compute the distances between a cluster of close voxels and the polygons selected by the culling operation so that the fast shared memory mechanism of the GPU can be fully utilized. The thickness/clearance of the objects is visualized by distributing points on the visible surfaces of the objects and painting them with a unique color corresponding to the thickness/clearance values at those points. A modified ray casting method is developed for computing the thickness/clearance using the distance field of the objects. A system based on these algorithms can compute the distance field of complex objects within a few minutes for most cases. After the distance field construction, thickness/clearance visualization at a near interactive rate is achieved

Automatic generation of photographic mosaics for poster presentations

研究成果の概要（和文）：手作業で行うには大変な労力を要するフォトモザイク（多数の写真を用いたコラージュにより別のモチーフを表現するアート手法）を、画像処理アルゴリズムで自動生成する手法を開発、改良した。本研究テーマにより開発したシステムにより、従来までは蓄積される一方であまり活用の場がなかった多数のデジタル写真を用いて、個人のセレモニーや地域のイベントなどに効果的に活用できるポスターが作成可能となった。これらの成果に基づいて、学術誌論文1篇、国際会議5件、国内会議5件の発表を行うとともに、および JR日立駅通路にてアート展示を実施し得られた知見の公開に努めた。 研究成果の概要（英文）：Photographic mosaics, which is a form of of media art and is based on　hundreds of photographs to produce a different motif, is automated using our image processing　algorithms. Our system provides opportunities to a number of dead-stocked digital photographs to be　built in a new poster presentation that can be used situations such as private ceremonies and local　events. Our findings have been presented in 5 international conferences and 5 domestic conferences,　as well as one academic journal paper. We also had a 2-week media art exhibition in JR Hitachi　station to publish our research results