Immersive Dome Projection: Skywalking Through Iconic Global Destinations
Nobuyuki Umezu; Shun Horie, Lead
IEEE Int. Conf. on Artificial Intelligence and Virtual Reality (AIxVR) 2025, Jan. 2025, [Reviewed]
Lossy Compression of Z-Map Based Shape Models Using Daubechies Wavelet Transform and QuickselectNobuyuki Umezu; Masatomo Inui, Lead, We propose an algorithm for lossy compression of computer-aided design models in Z-map representation. Our method employs Daubechies wavelet functions, which are smoother than those of the Haar wavelet used in a previous work for the lossy compression of shape models. A significant reduction in the amount of data of the compressed shape model was achieved using the proposed lossy in which the least significant coefficients of the wavelet synopsis were deleted. The nonlinear filtering of coefficients was based on the quickselect algorithm, which was seven to ten times faster than a normal quicksort algorithm and allowed us to accelerate the entire process. We conducted a series of experiments using shape models with 512 × 512–8192 × 8192 resolutions to evaluate our technique using various wavelet functions. The proposed method performed the process in 50–90 ms for the models at 1024 × 1024 resolution and reduced the output binary size by 75%–90% compared with those compressed using a previous method. Some Daubechies wavelets, such as D4 and D6, were found superior in lossy compression using nonlinear filtering based on the order of magnitude of wavelet coefficients., Fuji Technology Press Ltd.
International Journal of Automation Technology, 05 Sep. 2024,
[Reviewed] Interactive Projection on Objects: Book and Castle Ruin Model Cases in a Museum
Nobuyuki Umezu; Yuto Mori; Keita Yamura, Lead
Proc. of IEEE AIxVR 2024, Jan. 2024, [Reviewed]
Development of Pseudo-3D Representation for Two-Dimensional Artworks Based on Head Tracking and Depth Information
Yuming Bai; Nobuyuki Umezu, Last
Proc. of ACM ADIP 2023, Dec. 2023, [Reviewed]
Visitor Counting in a Museum With a 2D LiDAR Sensor
Nobuyuki Umezu; Shohei Koizumi, Lead
Proc. of IEEE GCCE 2023, Oct. 2023, [Reviewed]
Similarity-Based Grading Assistance for Assignments in Programming Lecture
Nobuyuki Umezu; Motoki Iwai; HIroto Ito, Lead
Proc. of IEEE GCCE 2023, Oct. 2023, [Reviewed]
Performance in Programming Class and Basic Math Skills
Nobuyuki Umezu; Motoki Iwai; HIroto Ito, Lead
Proc. of IEEE GCCE 2023, Oct. 2023, [Reviewed]
Potential of Low-Cost Light Detection and Ranging (LiDAR) Sensors: Case Studies for Enhancing Visitor Experience at a Science Museum
Nobuyuki Umezu; Shohei Koizumi; Kohki Nakagawa; Saku Nishida, Lead
Electronics, Jul. 2023, [Reviewed]
Graphical Assistance for Determining Cutter Axis Directions in 3+2-Axis Machining
Masatomo Inui; Shutaro Taguchi and Nobuyuki Umezu
CAD and Applications, Jan. 2023, [Reviewed]
Tangible User Interface to Learn about Voronoi Diagrams
Nobuyuki Umezu; Satoshi Iijima, Lead
Proc. of IEEE AIVR 2022, Dec. 2022, [Reviewed]
Visualizing Difference between Bodily Movements of Athletes and Users Learning to Play Baseball
Nobuyuki Umezu; Souta Akiyama, Lead
Proc. of IEEE AIVR 2022, Dec. 2022, [Reviewed]
Various Daubechies Wavelets for Compressing Z-map Models
Nobuyuki Umezu; Masatomo Inui, Lead
Proc. of ICPE 2022, Nov. 2022, [Reviewed]
Vectorization of Contours of Hand Written Letters for Character Mosaic Generation
Bai Yuming; Nobuyuki Umezu, Last
Proc. of ICPE 2022, Nov. 2022, [Reviewed]
Geometric Simulation of 5-axis Milling without Using Cutter Swept Volume
Shogo Iuchi; Masatomo Inui; Nobuyuki Umezu, Last
Proc. of ICPE 2022, Nov. 2022, [Reviewed]
Floor Projection with QR code-based Interactions and Visitor Drawings
Nobuyuki Umezu; Bai Yuming, Lead
Proc. of IEEE GCCE 2022, Oct. 2022, [Reviewed]
Formulation of Ever Zooming-up Photomosaics
Bai Yuming; Nobuyuki Umezu, Last
Proc. of IEEE GCCE 2022, Oct. 2022, [Reviewed]
Support for Hand Writing Practice with emphasized Visual Instructions
Natsumi Kako; Nobuyuki Umezu, Last
Proc. of IEEE GCCE 2022, Oct. 2022, [Reviewed]
Improved Method for Extracting Difficult-to-Machine Shapes Using Multiple Milling Simulation Results
Qi Chen; Masatomo Inui; Nobuyuki Umezu, Last
ASME IDETC/CIE 2022, Aug. 2022, [Reviewed]
Visualization of Thickness Distribution in Solid Objects
Masatomo Inui; Nao Oki; Nobuyuki Umezu
Proc. of ISFA 2022, Jul. 2022, [Reviewed]
Similarity-based Form Visualization for Supporting Sports Instructions
Souta Akiyama; Nobuyuki Umezu
Proc. of IEEE LifeTech2022, Mar. 2022, [Reviewed]
Chord-based Visualization of Temporal structure of Symphony
Kentarou Ishikawa; Nobuyuki Umezu
Proc. of IEEE LifeTech2022, Mar. 2022, [Reviewed]
Presenting Text Layout and Color Patterns Suitable for Book Covers
Naoki Kametani; Nobuyuki Umezu
Proc. of IEEE LifeTech2022, Mar. 2022, [Reviewed]
Comparison of Two Parallel Offsetting Algorithms Free from Conflicts Between Threads
Masatomo Inui; Daiki Ishii; and Nobuyuki Umezu
International Journal of Automation Technology (IJAT), Nov. 2021, [Reviewed]
Fast Cutter Accessibility Analysis Using Ray Tracing Cores of GPU
Masatomo Inui; Kohei Kaba; and Nobuyuki Umezu
International Journal of Automation Technology (IJAT), Nov. 2021, [Reviewed]
Parallel Contour-Type Cutter Path Computation Using GPU
Issei Watanabe; Masatomo INUI; Nobuyuki UMEZU
Proc. of LEM21 (International Conference on Leading Edge Manufacturing in 21st Century), Nov. 2021, [Reviewed]
Learning Environment based on an Interactive Projection Table for Children
Midori Kuwahara; Nobuyuki Umezu, Corresponding
Proc. of IEEE AIVR 2021, Nov. 2021, [Reviewed]
Character Mosaics: A New Form of Text-based Artistic Representation
Bai Yuming; Nobuyuki Umezu, Corresponding
Proc. of IEEE AIVR 2021, Nov. 2021, [Reviewed]
FAST CUTTER LOCATION SURFACE COMPUTATION USING RAY TRACING CORES
Daiki Ishii; Masatomo Inui; Nobuyuki Umezu
ASME IDETC/CIE 2021, Aug. 2021, [Reviewed]
Recipe Recommendation and Cooking Instruction based on Food Material Recognition,
Saki Asahina; Nobuyuki Umezu, Last
Proc. of QCAV 2021, May 2021, [Reviewed]
Supporting Sports Instruction with Comparative Display of Forms
Sota Akiyama; Nobuyuki Umezu, Last
Proc. of QCAV 2021, May 2021, [Reviewed]
Webcam-based Categorization of Task Engagement of PC Users at Work
Tadashi Ohara; Nobuyuki Umezu, Last
Proc. of QCAV 2021, May 2021, [Reviewed]
Parallel offset computation free from conflicts between threads
Daiki Ishi; Masatomo Inui; Nobuyuki Umezu
Proc. of ICPE 2020, Nov. 2020, [Reviewed]
Thickness evaluation of solid model in triple-dexel representation
Yu Huang; Masatomo Inui; Nobuyuki Umezu
Proc. of ICPE 2020, Nov. 2020, [Reviewed]
Accessibility Map for Assisting Cutter Posture Determination in Five-Axis Mold Machining
Masatomo Inui; Kouhei Nishimiya; Nobuyuki Umezu
Proc. of IEEE CASE 2020, Aug. 2020, [Reviewed]
Fast Dexelization of Polyhedral Models Using Ray-Tracing Cores of GPU
Masatomo Inui; Kohei Kaba; Nobuyuki Umezu
Proc. of CAD '20, Jul. 2020, [Reviewed]
Pseudo-3D Display Based on Head Tracking for Viewpoint Image Generation
Yuki Kubota; Nobuyuki Umezu, Corresponding
Proc. of IEEE GCCE 2019, Oct. 2019, [Reviewed]
CLEARANCE MEASUREMENT OF 3D OBJECTS USING ACCESSIBILITY CONE
Masatomo Inui; K. Nishimiya; Nobuyuki Umezu
ASME IDETC/CIE 2019, Aug. 2019, [Reviewed]
Milling simulation-based approach for determining optimal milling direction of ejector pin
Tong Zhang; Masatomo Inui; Nobuyuki Umezu
Proc. of I3CDE 2019, Jul. 2019, [Reviewed]
GEOMETRIC APPROACH FOR EVALUATING MANUFACTURABILITY OF PARTS PRODUCED WITH INJECTION MOLDING AND DIE CASTING
Masatomo Inui; Nobuyuki Umezu
Proc. of Model Based Enterprise Summit, 2019, Apr. 2019, [Reviewed]
Lossy compression with Daubechies wavelet transform for Z-Map Models
Nobuyuki UMEZU; Masatomo INUI
Proc. of ICPE 2018, Nov. 2018, [Reviewed]
Detection of Sphere Colliding Step Shape in Automobile Parts
Shun Nikaido; Masatomo Inui; Nobuyuki Umezu
Proc. of ICPE 2018, Nov. 2018, [Reviewed]
Support for Keyboard Performing Practice with Mirrored Video of Model Performance
Taisuke Nemoto; Nobuyuki Umezu
Proc. of IEEE GCCE 2018, Oct. 2018, [Reviewed]
Development of a Smart Mirror with Life Log Functions and Its Evaluation
Misaki Tani; Nobuyuki Umezu, Best Student Paper Award.
Proc. of IEEE GCCE 2018, Oct. 2018, [Reviewed]
RADIAL RAY REPRESENTATION FOR FAST ANALYSIS OF OPTIMAL CUTTING DIRECTION IN 3+2 AXIS MILLING
Masatomo Inui; Shinji Nagano; Nobuyuki Umezu
Proc. of ISFA 2018, Jul. 2018, [Reviewed]
Visualization of potential sink marks using thickness analysis of finely tessellated solid model
Masatomo Inui; Shunsuke Onishi; Nobuyuki Umezu
Journal of Computational Design and Engineering, 2018, [Reviewed]
Rapid Construction of Coarse Indoor Map for Mobile Robots
Eiji Kaneko; Nobuyuki Umezu
Proc. of IEEE GCCE 2017, Oct. 2017, [Reviewed]
Fast Extraction of Cutter Engagement Features by Using the Parallel Processing Function of a GPUMasatomo Inui; Masayoshi Kobayashi; Nobuyuki Umezu, 切削加工中に工具の切刃に作用する力の解析は，工具の変形量の評価や送り速度制御による切削効率化のための基礎情報として重要である．この種の解析では，切削シミュレーションにおいて，CEF(Cutter Engagement Feature)と呼ばれる工具と工作物の接触領域を計算する必要がある．高精度な解析のためには，工具が微小移動するたびにCEFを再計算する必要があり，膨大な計算時間が必要となってしまう．本研究では，近年性能向上の著しいGPU(Graphics Processing Unit)の並列処理機能を利用して，CEF計算を高速化する手法を提案する．システムを実装し計算実験により手法の有効性を検証した．, The Japan Society for Precision Engineering
Proc. of IEEE CASE 2017, Aug. 2017,
[Reviewed] Visualization of Possible Sink Marks using Thickness Analysis of Finely Tessellated Solid Model
Masatomo Inui; Shunsuke Ohnish; Nobuyuki Umezu
Proc. of ACDDE 2017, Aug. 2017, [Reviewed]
Evaluating the visibility of presentation slidesGenki Sugawara; Nobuyuki Umezu, Presentations using slide software such as PowerPoint are widely performed in offices and schools. The improvement of presentation skills among ordinary people is required because these days such an opportunity of giving presentation is becoming so common. One of the key factors for making successful presentation is the visibility of the slides, as well as the contents themselves. We propose an algorithm to numerically evaluate the visibility of presentation slides. Our method receives a presentation as a set of images and eliminates the background from the slides to extract characters and figures. This algorithm then evaluates the visibility according to the number and size of characters, their colors, and figure layouts. The slide evaluation criteria are based on the series of experiments with 20 participants to parameterize typical values for visual elements in slides. The algorithm is implemented on an iMac and takes 0.5 sec. to evaluate a slide image. The evaluation score is given as a value between 0 and 100 and the users can improve their slide pages with lower scores. Our future work includes a series of experiments with various presentations and extending our method to publish as a web-based rating service for learning presentation skills., SPIE-INT SOC OPTICAL ENGINEERING
Proc. of QCAV 2017, May 2017,
[Reviewed] Features contributing sense of scale in photographsNobuyuki Umezu, Miniature-like photographs of real scenery can be obtained by focusing only on a very small area on the film in an analog camera, as well as by post-processing by computers. Such a sense of miniature on human vision has not been well examined so far. This paper investigates image features contributing sense of scale in photographs. Three key features; blur, saturation and intensity of images are examined with their effects on the enhancement of miniature effects in user experiments. The degrees of these three features are varied for generating sample images presented in the experiments. The participants evaluated the degree of miniature effect of presented images on a 0-10 scale. The results have shown that these three factors account for 79% of the subject evaluations and their coefficients 2.02, 1.72, and 0.37 were obtained by a multiple regression analysis. These facts suggest that the saturation of images, as well as blur, highly affects the sense of scale in human vision. A series of experiments on a variety of features with a number of images should be conducted in future work., SPIE-INT SOC OPTICAL ENGINEERING
Proc. of QCAV 2017, May 2017,
[Reviewed] Prototype implementation of mirror with built-in displayMisaki Tani; Nobuyuki Umezu, People who are unfamiliar with digital equipments might have a feeling of inferiority in the coming ubiquitous computing age. Such a circumstance can be solved with equipments that never seem to be based on digital technology. In this paper, we propose a smart mirror with displays and cameras inside to offer various functions such as portrait logging, appearance self-check, and information display. A prototype implementation with an iMac and a Kinect sensor is presented as well as human detection with a depth template and motion detection to turn on instant logging. Our future work includes completing the development and conducting user experiments., SPIE-INT SOC OPTICAL ENGINEERING
Proc. of QCAV 2017, May 2017,
[Reviewed] 2D Wavelet Transform Data Compression with Error Level Guarantee for Z-Map ModelsNobuyuki Umezu; Keisuke Yokota; Masatomo Inui, Most of workpiece shapes in NC milling simulations are in Z-map representations that require a very large amount of data to precisely hold a high resolution model. An irreversible compression algorithm for Z-map models using a two-dimensional Haar wavelet transform is proposed to resolve this tight memory situation for an ordinary PC. A shape model is first transformed by using Haar wavelet to build a wavelet synopsis tree while the maximum errors caused by virtually truncating high-frequency components are simultaneously calculated. The total amount of the shape data can be reduced by truncating particular sections of the wavelet components that satisfy the error threshold given by the user. Our algorithm guarantees that any error due to its irreversible compression processes is smaller than the specified level measured against the original model. A series of experiments were conducted using an Apple iMac with a 3.2 GHz CPU and 8 GB of memory. The experiments were performed with 16 sample shape models on 512×512 to 8192×8192 grids to evaluate the compression efficiency of the proposed method. Experimental results confirmed that our compression algorithm requires approximately 20–30 ms for 512×512 models and 7 s for 8192×8192 models under a maximum error level of 10× 10−6 m (a typical criteria for NC milling simulations). The compressed binaries outputted by the proposed method are generally 25–35% smaller than the baseline results by gzip, one of common reversible compression libraries, while these two methods require almost the same level of computational costs., Elsevier Ltd
Journal of Computational Design and Engineering, 2017,
[Reviewed] Simple Offset Algorithm for Generating Workpiece Solid Model for Milling SimulationMasatomo Inui; Nobuyuki Umezu; Masashi Tsukahara, In the milling simulation of a large stamping die for an automobile part, a workpiece solid model is necessary as an input data. The initial shape of the workpiece is generally equivalent to an offset shape of the stamping die CAD model. Accurate offset shape is not a requirement on the workpiece solid model for the milling simulation. In this paper, we propose a novel method named "Simple Offset" for fast and stable generation of a simplified offset shape of a polyhedral solid model. In this method, surface points of the offset shape are sampled using 3 mutually perpendicular grids in the model space. The final offset shape is obtained by properly connecting the sampled points. Simplification level of the offset shape can be controlled by changing the resolution of the grids for sampling the surface points. An experimental system is implemented and some computation results are demonstrated., JAPAN SOC MECHANICAL ENGINEERS
JAMDSM, 2017,
[Reviewed] Photographic Mosaics Maintaining Image Boundaries
Nobuyuki Umezu
Proc. of A-DEWS 2016, Dec. 2016, [Reviewed]
Reduction of reworks by detecting possible manufacturing problems of plastic and diecasting parts in early design stage
Masatomo Inui; Nobuyuki Umezu
Proc. of A-DEWS 2016, Dec. 2016, [Reviewed]
Photographic Mosaics MaintaThickness Visualization based on Distance Field of 3D Objectsining Image Boundaries
Takuya Iwanami; Masatom Inui; Nobuyuki Umezu
Proc. of ICPE 2016, Nov. 2016, [Reviewed]
2D Wavelet Transform Data Compression with Error Level Guarantee for Z-Map Models
Keisuke Yokota; Nobuyuki Umezu; Masatomo Inui
Proc. of ACDDE 2016, Oct. 2016, [Reviewed]
Solid Model Simplification Using Triple Dexel Representation
Masatomo Inui; Nobuyuki Umezu and Masashi Tsukahara
Proc. of ACDDE 2016, Oct. 2016, [Reviewed]
Photographic Mosaics Maintaining Image Boundaries
Nobuyuki Umezu
Proc. of ACDDE 2016, Oct. 2016, [Reviewed]
Milling Result Visualization for Assisting Process Planning of Mold Parts with Complex Pocket FeaturesMasatomo Inui; Nobuyuki Umezu, In the machining process planning of plastic molds, an estimation of the machining result that is realizable with a specific cutter is frequently needed. In this paper, we propose a novel method for computing the result shape using geometric models of the part, the workpiece before machining, and the cutter. This method is especially useful for mold parts with complex pocket features. The machining of a pocket uses a milling method with a cutter gradually approaching the pocket by following a downward slope. In this method, a gap distance is required between the cutter and the wall surfaces of the pocket. We have developed an inverted-offset-based method for evaluating this geometric constraint in the determination of the maximum milling depth of the pocket. Because this method does not consider any shape descriptions from the form feature database, it is applicable to any form features with certain depressions, like slot features., IEEE
Proc. of ISFA 2016, Aug. 2016,
[Reviewed] Recognition of Narrow and Deep Slot Features of a Part Using External Distance FieldMasatomo Inui; Tomohiro Imai; Nobuyuki Umezu, Injection molding is commonly used for fabricating plastic parts of consumer products. In this method, melted hot material is highly pressurized and forced into a space between the mold core and cavity. Thin wall shapes in the mold core are often deformed in the injection process, and plastic parts with defective shapes are produced. Detection of such problems in the manufacturing process causes costly rework of the part design. A fast inspection method that allows the part designers to check for possible problems in the later manufacturing stage is desired. Thin-walled shapes in the mold core correspond to narrow and deep slot features in the part. Our method can detect such slots by using the external distance field of the part. An experimental recognition system is implemented using the proposed algorithm. Our system can recognize all narrow and deep slots on a part in 5 to 15 min., IEEE
Proc. of ISAM 2016, Aug. 2016,
[Reviewed] GPU-Based Visualization of Knee-Form Contact Area for Safety Inspections
Masatomo Inui; NobuyMasatomo Inui; Shunsuke Nakano; Nobuyuki Umezu; Tetsuya Asanouki Umezu
Proc. of CAD 2016, Jun. 2016, [Reviewed]
Wavelet Transform Data Compression with an Error Level Guarantee for Z-Map ModelsNobuyuki Umezu; Kazuki Asai; Masatomo Inui, This paper proposes an algorithm to compress CAD models in a grid-based Z-map representation while keeping the compression artifacts within a specified value (the maximum difference allowed by the user). A wavelet transformis used for decomposing the input shape into lower and higher frequency patterns. A significant reduction in the data size can be achieved by deleting higher frequency components. We employ a tree structure called the error range (ER) tree to manage error occurrences and determine where to prune branches without increasing the resulting errors in the data compression. The widely used reversible compression method, gzip, is then used to obtain the final compressed model data output. We conducted a series of experiments with 12 sample shape models on a 512 × 512 grid. With a maximum error of 10 μm (a typical value specified for NC milling), the proposed method reduces the data by 90.9% on average and the computational cost of 19 ms is extremely low. The proposed method can be extended to larger CAD models in real applications., Fuji Technology Press
International Journal of Automation Technology (IJAT), May 2016,
[Reviewed] Shrinking sphere: A parallel algorithm for computing the thickness of 3D objectsMasatomo Inui; Nobuyuki Umezu; Ryohei Shimane, An interactive system is required to enable machine designers to precisely visualize the thickness of a machine part. The thickness of a 3D object at a surface point is given by the diameter of the maximum inscribed sphere (MIS) touching that point. In this paper, we propose a novel iterative algorithm, namely, the shrinking sphere algorithm, for computing the MIS at a specific surface point. The convergence speed of the proposed algorithm is very high, and several iterations are usually sufficient for obtaining the MIS. The parallel execution of the algorithm with a graphics processing unit (GPU) is presented for further improving the computation speed. On the basis of the proposed algorithm, an experimental thickness visualization system is implemented using Compute Unified Device Architecture (CUDA). This system can visualize the thickness of a complex object with nearly two million polygons in several minutes using a PC (Core i7 CPU, 32GB memory and GTX-980 GPU), which is sufficiently fast for practical purposes., Taylor and Francis Inc.
Computer-Aided Design and Applications, 03 Mar. 2016,
[Reviewed] Wavelet transform data compression with an error level guarantee for Z-map modelsNobuyuki Umezu; Kazuki Asai; Masatomo Inui, This paper proposes an algorithm to compress CAD models in a grid-based Z-map representation while keeping the compression artifacts within a specified value (the maximum difference allowed by the user). A wavelet transformis used for decomposing the input shape into lower and higher frequency patterns. A significant reduction in the data size can be achieved by deleting higher frequency components. We employ a tree structure called the error range (ER) tree to manage error occurrences and determine where to prune branches without increasing the resulting errors in the data compression. The widely used reversible compression method, gzip, is then used to obtain the final compressed model data output. We conducted a series of experiments with 12 sample shape models on a 512 × 512 grid. With a maximum error of 10 μm (a typical value specified for NC milling), the proposed method reduces the data by 90.9% on average and the computational cost of 19 ms is extremely low. The proposed method can be extended to larger CAD models in real applications., Fuji Technology Press
International Journal of Automation Technology, 2016,
[Reviewed] Contents-based Thumbnailing for Short Video
Kazuki Yuasa; Nobuyuki Umezu
Proc. of ACDDE 2015, Nov. 2015, [Reviewed]
Accelerating Thumbnail Generation from JPEG Images
Tatsuya Nakayari; Nobuyuki Umezu
Proc. of ACDDE 2015, Nov. 2015, [Reviewed]
Thinning Algorithm of Front Grille Part Shape for Air Flow Analysis
Masatomo Inui; Nobuyuki Umezu; Masahiko Tadaki
Proc. of ACDDE 2015, Nov. 2015, [Reviewed]
Extracting Object Position Characteristics from Images on the Web
Fiji Kaneko; Nobuyuki Umezu
Proc. of ACDDE 2015, Nov. 2015, [Reviewed]
Computer-Aided Coloring of Monochrome Images
Yuka Kanahama; Nobuyuki Umezu
Proc. of ACDDE 2015, Nov. 2015, [Reviewed]
Visualizing Color Term Differences based on Images on the Web
Nobuyuki Umezu; Eriho Takahashi
Proc. of ACDDE 2015, Nov. 2015, [Reviewed]
Thickness and clearance visualization based on distance field of 3D objectsMasatomo Inui; Nobuyuki Umezu; Kazuma Wakasaki; Shunsuke Sato, 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., Society for Computational Design and Engineering
Journal of Computational Design and Engineering, 01 Jul. 2015,
[Reviewed] Visualizing sphere-contacting areas on automobile parts for ECE inspectionMasatomo Inui; Nobuyuki Umezu; Yuuki Kitamura, 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., Society for Computational Design and Engineering
Journal of Computational Design and Engineering, 01 Jan. 2015,
[Reviewed],
[Invited] Parallel Distance Field Computation with GPU and Its Application for Evaluating Part Thickness
Masatomo INUI; Nobuyuki UMEZU; Koudai KOBAYASHI
Proc. of ISFA 2014, Jul. 2014, [Reviewed]
Automatic detection of the optimal ejecting direction based on a discrete Gauss mapMasatomo Inui; Hidekazu Kamei; Nobuyuki Umezu, 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., Society for Computational Design and Engineering
Journal of Computational Design and Engineering, 01 Jan. 2014,
[Reviewed],
[Invited] Automatic detection of the optimal ejecting direction based on a discrete Gauss map
Masatomo INUI; Nobuyuki UMEZU; Hidekazu Kamei
Proc. of ACDDE 2013, Dec. 2013, [Reviewed]
Fast Detection of Head Colliding Shapes on Automobile PartsMasatomo Inui; Nobuyuki Umezu, In the ECE regulation, any surface of the interior part of automobiles must have sufficient roundness where a sphere of diameter 165mm, which is equivalent to the average head size of infants, may collide. A system for automatically detecting sphere contacting shape on the automobile part is developed. In the current practice, some Japanese automobile manufactures detect the shape by using the virtual milling method. In this method, a milling simulation with a ball end cutter of diameter 165mm is executed on the part to detect the sphere contacting shape. The method generally needs a lot of computation time for the detection. In this paper, the authors propose an improved virtual milling method for fast detecting the sphere contacting shape. Our algorithm initially generates points sufficiently covering the visible surface of the model. For each point, the contact condition of the cutter is evaluated by using the inverted offset surface of the part. An inverted offsetting method accelerated with the depth buffer mechanism of GPU is introduced. An experimental system is implemented and some computational experiments are performed. Our system can detect the sphere contacting shape on the part surface with approximately 1 million polygons in a few seconds. © 2013 by JSME.
Journal of Advanced Mechanical Design, Systems, and Manufacturing, Sep. 2013,
[Reviewed],
[Invited] A Comparison of Two GPU Accelerated Geometric Milling Simulation Methods
Masatomo INUI; Nobuyuki UMEZU; and Yuki SHINOZUKA
Proc. of ISFA 2012, Mar. 2013, [Reviewed]
A COMPARISON OF TWO METHODS FOR GEOMETRIC MILLING SIMULATION ACCELERATED BY GPUMasatomo Inui; Nobuyuki Umezu; Yuuki Shinozuka, For detecting potential problems of a cutter path, cutting force simulation in the NC milling process is necessary prior to actual machining. A milling operation is geometrically equivalent to a Boolean subtraction of the swept volume of a cutter moving along a path from a solid model representing the stock shape. In order to precisely estimate the cutting force, the subtraction operation must be executed for every small motion of the cutter. The performance and the cost of the polygon rendering LSI called GPU are dramatically improved these days. By using GPU, the required time for critical computations in the geometric milling simulation can be drastically reduced. In this paper, the computation speed of two known GPU accelerated milling simulation methods, which are the depth buffer based method and the parallel processing based method with CUDA language, are compared. Computational experiments with complex milling simulations show that the implementation with CUDA is several times faster than the depth buffer based method when the cutter motion in the simulation process is sufficiently small., AMER SOC MECHANICAL ENGINEERS
PROCEEDINGS OF THE ASME/ISCIE INTERNATIONAL SYMPOSIUM ON FLEXIBLE AUTOMATION, ISFA 2012, 2013,
[Reviewed] Automatic detection of ejection direction of a part with the minimum undercuts
Masatomo INUI; Hidekazu KAMEI; Nobuyuki UMEZU
Proc. of ACDDE 2012, Dec. 2012, [Reviewed]
Fast Detection of Head Colliding Shapes on Automobile Parts
Masatomo INUI; Nobuyuki UMEZU
Proc. of ACDDE 2012, Dec. 2012, [Reviewed]
Cutter Engagement Feature Extraction by Using Dexel Representation Solid ModelMasatomo Inui; Nobuyuki Umezu, Computer simulation of the cutting force change in a milling process is important for realizing more stable, precise, and efficient metal cutting. In the latest cutting force simulation method, a cutter engagement feature representing a contact area between the milling cutter and the workpiece must be extracted for each small motion of the cutter. In this paper, a new algorithm is proposed for computing a cutter engagement feature based on the dexel representation of the workpiece. Most prior studies compute the feature based on the cutter removal volume of the workpiece. Differently from them, our technology computes the cutter engagement feature based on the contact analysis between the cutter and dexels representing the workpiece shape. An experimental system is implemented and computational experiments are performed. Our system can complete the cutter engagement feature extraction of a complex 3-axis NC milling process in a few minutes., TRANSACTION PUBLISHERS
Proc. of ICPE 2012, Nov. 2012,
[Reviewed] Cutter Engagement Feature Extraction by Using Dexel Representation Solid ModelMasatomo Inui; Nobuyuki Umezu, Computer simulation of the cutting force change in a milling process is important for realizing more stable, precise, and efficient metal cutting. In the latest cutting force simulation method, a cutter engagement feature representing a contact area between the milling cutter and the workpiece must be extracted for each small motion of the cutter. In this paper, a new algorithm is proposed for computing a cutter engagement feature based on the dexel representation of the workpiece. Most prior studies compute the feature based on the cutter removal volume of the workpiece. Differently from them, our technology computes the cutter engagement feature based on the contact analysis between the cutter and dexels representing the workpiece shape. An experimental system is implemented and computational experiments are performed. Our system can complete the cutter engagement feature extraction of a complex 3-axis NC milling process in a few minutes., TRANSACTION PUBLISHERS
Key Engineering Materials, Nov. 2012,
[Reviewed] 考古学における遺構実測図のベクトル化アルゴリズム梅津信幸; 長谷川修一, We present an algorithm for vectorizing measured drawings of archaeological remains. Since archaeological excavation is essentially a destructive process, measured drawings are one of the most important records. Most of these drawings are first hand-drawn at excavation sites and then archaeologists spend an enormous amount of time clicking several points to convert scanned drawings into digital vector formats. Our raster-vector conversion algorithm will make this process more convenient. The algorithm assumes that a measured drawing has three layers: first, periodical sectional patterns on a sheet of paper; second, connected components of measured archaeological objects, and third, annotations with long lines. Vectorization experiments were done with scanned measured drawings of the archaeological remains at Tel Rekhesh, Israel. The resultant drawings demonstrate that our algorithm can significantly reduce the following process of manual clicking and editing. Future work will include the implementation of a web service to convert raster images into vector drawings and the improvement of the proposed algorithm by using more of these drawings., The Institute of Image Information and Television Engineers
映像情報メディア学会 論文誌, Jul. 2012,
[Reviewed] A Comparison of Two GPU Accelerated Geometric Milling Simulation Methods
Masatomo INUI; Nobuyuki UMEZU; Yuki SHINOZUKA
Proc. of ISFA 2012, 18 Jun. 2012, [Reviewed]
フーリエ変換強度差分を用いた欠陥検出法の実装と評価梅津信幸; 小野達矢; 清水勲; 鵜野克宏, This paper presents a defect detection method based on two dimensional Fourier transform. In automatic visual inspection in factories, the displacement between two inspected images contains both parallel shift and rotation, which causes the inspection process to be highly time-consuming. In the proposed method, the subtraction between Fourier transform magnitudes of two input images is calculated for detecting differences between the corresponding pixels. Due to the shift- invariant nature of magnitudes in Fourier transform spectrum, the method does not require an image registration process for parallel shift. For images rotated by a small angle, a correlation based on one dimensional Fourier transform is calculated to estimate the angle.Detection experiments are executed on Mac Pro 2.66GHz using images with 256 × 256 to 4000 × 2672 pixels. For the largest resolution images, the method detects differences in 2.39 seconds. The experimental results show that the proposed method has sufficient detection precision and faster computation speed than existing visual inspection methods. Estimation of specular reflection on PCB surfaces and further acceleration of the calculation are to be implemented., The Japan Society for Precision Engineering
精密工学会論文誌, Jun. 2012,
[Reviewed] Fast Estimation of Milling Result with GPU
Masatomo INUI; Nobuyuki UMEZU; Marie FUSHIMI
Advanced Science Letters, May 2012, [Reviewed]
仮想的な金型製造によるプレス金型間のクリアランス検証乾正知; 長谷川裕二; 梅津 信幸, In the press-working of sheet metal parts for automobile bodies, two stamping die CAD models with mutually inverted curved surfaces are necessary. They are designed to have some clearance between them when they are assembled so that they can properly hold a sheet metal within. Since these two models have very similar curved surfaces, engineers usually design a single CAD model only. The other model is obtained by copying, partly modifying, and inverting the designed model. The modification is generally very small and limited, and the visual inspection of the modified shape is difficult. False modifications often cause bad results in the later trial press-working process and expensive design reworks become necessary. In order to assist the stamping die designer, the authors developed an algorithm for visually inspecting the clearance between the designed model and virtually machined model of its modified counterpart. A fast clearance inspection between 2 models is achieved by using the hierarchical structure of OBBs and the multiple-threading technology., The Japan Society for Precision Engineering
精密工学会論文誌, Jan. 2012,
[Reviewed] Detection of image differences by Fourier transformed magnitude subtractionKatsuhiro Uno; Isao Shimizu; Hiroyasu Murakami; Nobuyuki Umezu, We propose a method for high-speed and highly accurate detection of the image difference by using the Fourier spectrum magnitude difference. The difference can be extracted from subtraction between the Fourier spectrum magnitude images of a standard image and a target image, which are multiplied by their Fourier spectrum phase images. The size effect against the detection result of difference was also investigated. (C) 2012 Elsevier GmbH. All rights reserved., ELSEVIER GMBH, URBAN & FISCHER VERLAG
OPTIK, 2012,
[Reviewed] Fast estimation of milling result with geometric processing unitMasatomo Inui; Nobuyuki Umezu; Marie Fushimi, In this paper, the authors propose a new method for estimating the result shape of the milling operation. The automation of the process planning is strongly requested for realizing faster and more economical production of the mold and die. Our developed technology is expected to be used as a basic tool for the process planning automation. Milling result estimation is realized in 3 steps, initial cutter path generation, modification of the cutter path for avoiding holder collisions, and milling simulation. In the last step, some portions of the workpiece are removed, therefore the cutter can mill the workpiece more deeply without holder collisions. Our system thus modifies the cutter path according to the updated workpiece shape and executes the milling simulation again. This simulation and path modification processes are iterated until the workpiece removal by the cutter does not occur. The cutter path generation and the milling simulation are generally time-consuming. Our system realizes the fast computation with good use of the hardware acceleration with GPU. The developed system can visualize the milling result in a minute even for a large mold of an automobile bumper. © 2012 American Scientific Publishers.
Advanced Science Letters, 2012,
[Reviewed] Fast Safety Verification of Interior Parts of AutomobilesSatoru YAMAZAKI; Tatahiro BABA; Nobuyuki UMEZU; Masatomo INUI, A program for automatically verifying safety regulations specified on the interior part of the automobile is developed. In the ECE regulation, any surface of the interior part is requested to have roundness larger than R3.2 where a sphere of diameter 165mm can collide. Our developed program initially generates points sufficiently covering the visible surface of the model. For each point, sphere-object intersections associated with the regulations are evaluated. If the surface portion around the point cannot satisfy the geometric condition of the regulation, red color is painted to the point. As the result, corner shapes of the CAD model with possibly injuring the driver and passenger in the car crash are extracted and displayed. © 2011 IEEE.
Proc. of ICMA 2011, 10 Aug. 2011,
[Reviewed] 並列処理を用いた立体モデルの高速な厚み評価技術の開発山崎悟; 梅津信幸; 乾正知, In the current manufacturing practice, injection molding is widely used for fabricating plastic parts of various consumer products, such as digital cameras, printers and other electric appliances. In designing a plastic part, thickness of the part is defined to be constant all over the surface, otherwise some deformations happen in the molding process which deteriorate the aesthetic quality of the product. In this paper, the authors propose a fast algorithm for evaluating the thickness of the solid model. Existing commercial CAD systems provide some thickness measuring functions of solid models. These functions are, however, not appropriate for evaluating thickness of the complex shape. In this paper, a new definition of the thickness of the solid model is proposed. Using the definition, a fast thickness evaluation algorithm with the oriented bounding box (OBB) and the parallel processing capability of GPU is developed. A system is implemented and some computational experiments are performed., The Japan Society for Precision Engineering
精密工学会論文誌, Aug. 2011,
[Reviewed] A Hybrid Collision Detection Method for Anti-Crash
Masatomo INUI; Nobuyuki UMEZU and Yuji HASEGAWA
Proc. of ACDDE 2011, 2011, [Reviewed]
A Dexl Based Algorithm for Evaluating Thickness of Solid Models
Satoru Yamazaki; Nobuyuki Umezu; Masatomo Inui
ACDDE2010, Proc. of Asian Conference of Design & Digital Engineering, 27 Aug. 2010, [Reviewed]
GPU Acceleration of 5-Axis Milling Simulation in Triple Dexel Representation
Masatom Inui; Nobuyuki Umezu
ISFA2010, Proc. of International Symposium of Flexible Automation, 14 Jul. 2010, [Reviewed]
３方向デクセルモデルによる同時５軸制御加工の幾何シミュレーション乾正知; 梅津信幸, In the triple dexel model, object shape is represented by 3 groups of axis aligned segments named x-axis dexels, y-axis dexels, and z-axis dexels. Triple dexel model is known as compact and precise representation compared with other discrete solid representation schemes. Based on the triple dexel representation, a new 5-axis milling simulation system is developed. Differently from prior systems, this system uses GPU technology for accelerating 3 important processing steps in the milling simulation, which are (1) cutter swept volume generation, (2) subtraction of the swept volume from the workpiece solid model, and (3) update of the workpiece picture for achieving smooth animation of the milling process. An experimental system is implemented and some computational experiments are performed. Our system can realize a simulation of a complex 5-axis milling process in a few minutes. The animation speed is generally more than 100 frames per second., The Japan Society for Precision Engineering
精密工学会論文誌, Mar. 2010,
[Reviewed] ３方向デクセルモデルとポリゴンモデルの相互変換技術乾正知; 櫻井貴; 梅津信幸, In the triple dexel model, an object shape is represented with 3 groups of axis aligned segments named X-dexels, Y-dexels, and Z-dexels. In this paper, the authors propose a data conversion method from a conventional polygonal model such as STL to a triple dexel model, and vice versa. In this method, the following technology is employed; (1) Data conversion from a polygonal model to a triple dexel model is realized by multiple applications of "depth peeling". This process can be accelerated by using the depth buffer and stencil buffer mechanisms of GPU. (2) Data conversion from a triple dexel model to a polygonal model is realized by gathering and classifying polygons attached to the end point of neighboring dexels. An experimental conversion program is implemented and some computational experiments are performed. Our program can convert a polygonal model with 3,000,000 polygons to a triple dexel model with 1024 x 1024 resolution grids in 8 seconds. Reverse conversion from a triple dexel model to a polygonal model is realized in a second., The Japan Society for Precision Engineering
精密工学会論文誌, Feb. 2010,
[Reviewed] Multiresolution Volume Data Structure for Shape ModelingN Umezu; Y Shinagawa; TL Kunii, Due to the rapid progress of computer hardware, handling large volume data is getting easier. Although a number of methods have been developed for rendering volumetric datasets, very few have been proposed for shape modeling of such datasets.
This paper describes a multiresolution structure for shape modeling with volume data, and the voxel interaction method capable of modeling shapes at arbitrary resolution level. In the voxel interaction method, each voxel acts in a similar way to cellular automaton. The shape of an object is represented by the internal variables in the voxels. Unlike cellular automata, the interacting voxels can change the speed of the information propagation by selecting an appropriate resolution in the hierarchical structure, which plays an important role in modeling the rigidity of objects in our method. For acceleration of rendering for 2D image generation, the sampling ratio along the eye-ray in the volume space is determined according to the resolution of the volume data. Experimental results include the examples of shape deformation of human CT data., IEEE COMPUTER SOC
Proceedings of Multi Media Modeling'98, Oct. 1998,
[Reviewed]
