{"created":"2023-05-15T15:29:46.174692+00:00","id":19598,"links":{},"metadata":{"_buckets":{"deposit":"1a9f77bd-c373-43dc-9daf-b298eb86f7f2"},"_deposit":{"created_by":15,"id":"19598","owners":[15],"pid":{"revision_id":0,"type":"depid","value":"19598"},"status":"published"},"_oai":{"id":"oai:sucra.repo.nii.ac.jp:00019598","sets":["94:429:431:432:1016"]},"author_link":["30431"],"item_113_alternative_title_1":{"attribute_name":"タイトル（別言語）","attribute_value_mlt":[{"subitem_alternative_title":"2台のハンドヘルドカメラを用いた表面の粗い材料の反射測定"}]},"item_113_biblio_info_9":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2021","bibliographicIssueDateType":"Issued"}}]},"item_113_date_35":{"attribute_name":"作成日","attribute_value_mlt":[{"subitem_date_issued_datetime":"2022-06-15","subitem_date_issued_type":"Created"}]},"item_113_date_granted_20":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2021-03-25"}]},"item_113_degree_grantor_22":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"埼玉大学"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"12401","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_113_degree_name_21":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士(工学)"}]},"item_113_description_13":{"attribute_name":"形態","attribute_value_mlt":[{"subitem_description":"114p","subitem_description_type":"Other"}]},"item_113_description_23":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":" In this thesis, we propose a method that can measure the spatially-varying relectance of anisotropic materials to reproduce the realistic appearance. The simple apparatus is used to measure both isotropic and anisotropic materials.\n The appearance of the real materials changes under various illumination conditions according to the type of materials, surface geometry, and reflectance properties. Anisotropic reflection is a technique that transforms the reflected light of lighting into an elongated shape in the vertical and horizontal directions, and is called Anisotropy. For isotropic materials, the appearance on the surface is almost the same since the surface geometry is homogeneous, and the reflectance does not change about its rotation of geometric normal, as is the case with the metallic material. Anisotropic materials have complex surface texture, and their geometric normals as well as the roughness values are varied in all spatial points across the surface. Consequently, the surface reflectance changes as it rotates about its geometric normal, as is the case with velvet. Therefore, it is more challenging to measure the spatially-varying reflectance of anisotropic materials. The reflectance is measured by various measurement methods using calibrated cameras, light sources and multiple controllers in many existing systems. However, their methods are expensive, require wide space, and normally time-consuming.\n In our method, we use two handheld cameras by combining with a small LED light, a turning table, and a chessboard with markers. The two cameras are used as the view and light cameras respectively to acquire the incoming and outgoing light directions simultaneously, and the brightness at each position on the target material as well. We characterize the surface reflectance using the bidirectional reflectance distribution function (BRDF) model. The spherical polar coordinate system is used to calculate the distributions of normal directions across the surface. All model parameters at each position on the material surface, as well as the normal directions, and anisotropic directions are optimized by non-linear optimization.\n In this thesis, we firstly measure the anisotropic reflectance of a spatial point on the material surface. We characterize the surface reflectance using the anisotropic Ward bidirectional reflectance distribution function (BRDF) model. The initial values of the anisotropic direction are given based on the peak specular lobe on the surface, and the best-fitted one is chosen for the anisotropic direction. All model parameters as well as the anisotropic direction are optimized by non-linear optimization method.\n Then, we measure the spatially-varying reflectance of all points across the surface. The reflectance is optimized using the isotropic Ward BRDF model. The normal directions and all model parameters at each position on the material surface are optimized by nonlinear optimization. Then, we measure the spatially-varying reflectance of anisotropic materials for all points across the surface. The reflectance is approximated using the anisotropic Ward BRDF model. The model parameters, as well as the normal directions and anisotropic directions for each spatial point are estimated by two step processes and optimized by non-linear optimization method. In each step, the initial values for each parameter are given by iterative method. Then, the well-fitted parameters are retrieved according to the minimum of residuals based on the least root-mean-square-error (RMSE) method.\n As the result of experiments, the BRDF parameters were well-estimated, and the correct colors were reproduced as RGBA images. Moreover, the normal directions, as well as the anisotropic directions for all spatial points were properly estimated. For anisotropic materials, the highlight changes on the surfaces were observed when we moved the light source or the rendered materials.\n It was confirmed that our apparatus is easy to use and was able to measure. The realistic appearance of objects which can support users to perceive the material can be reproduced, and the spatially-varying reflectance of real materials can be measured.","subitem_description_type":"Abstract"}]},"item_113_description_24":{"attribute_name":"目次","attribute_value_mlt":[{"subitem_description":"Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12\nAbstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13\n\n1 Introduction 15\n　1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15\n　1.2 Problem Formulation . . . . . . . . . . . . . . . . . . . . . . . . . . 18\n　1.3 Objectives and Contributions of this Thesis . . . . . . . . . . . . . 20\n　1.4 Organization of this Thesis . . . . . . . . . . . . . . . . . . . . . . . 20\n\n2 Related Work 22\n　2.1 Measuring Reflectance using Gonioreflectometer . . . . . . . . . . . 22\n　2.2 Measuring Reflectance using Lighting Gantry . . . . . . . . . . . . 25\n　2.3 Measuring Reflectance using Customized Setup . . . . . . . . . . . 27\n　2.4 Measuring Reflectance using Mobile Phone and Laptop Screen . . . 28\n\n3 Proposed Method 31\n　3.1 Measurement Apparatus . . . . . . . . . . . . . . . . . . . . . . . . 31\n　3.2 Measurement Method . . . . . . . . . . . . . . . . . . . . . . . . . . 32\n　3.3 Acquisition of the Camera Pose . . . . . . . . . . . . . . . . . . . . 34\n　3.4 Measuring the Reflectance at a Spatial Point of Anisotropic Materials 35\n　　　3.4.1 Estimation of the BRDF Parameters . . . . . . . . . . . . . 36\n　3.5 Measuring the Spatially-varying Reflectance of Isotropic Materials . 38\n　　　3.5.1 Estimation of the BRDF parameters . . . . . . . . . . . . . 39\n　3.6 Measuring the Spatially-varying Reflectance of Anisotropic Materials 40\n　　　3.6.1 Spatially-varying Anisotropic Reflectance Measurement method 40\n　　　3.6.2 Two Steps Parameters Estimation Process . . . . . . . . . . 41\n　3.7 Measuring the Spatially-varying Reflectance of Isotropic Materials . 42\n　　　3.7.1 Rendering Result . . . . . . . . . . . . . . . . . . . . . . . . 43\n　　　3.7.2 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43\n\n4 Experimental Result 48\n　4.1 Measuring the Reflectance at a Spatial Point of Anisotropic Materials 48\n　　　4.1.1 Fitting Result . . . . . . . . . . . . . . . . . . . . . . . . . 49\n　　　4.1.2 Rendering Result . . . . . . . . . . . . . . . . . . . . . . . . 49\n　　　4.1.3 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49\n　4.2 Measuring the Spatially-varying Reflectance of Isotropic Materials . 50\n　　　4.2.1 Rendering Result . . . . . . . . . . . . . . . . . . . . . . . . 50\n　　　4.2.2 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50\n　4.3 Measuring the Spatially-varying Reflectance of Anisotropic materials 51\n　　　4.3.1 Step 1 Measurement Result of Plain Fabric Material . . . . . 52\n　　　4.3.2 Step 2 Measurement Result of Plain Fabric Material . . . . . 53\n　　　4.3.3 Step 1 Measurement Result of Floral Fabric Material . . . . 55\n　　　4.3.4 Step 2 Measurement Result of Floral Fabric Material . . . . 56\n　　　4.3.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58\n\n5 Conclusion and Future Work 108\n　5.1 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108\n　5.2 Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108","subitem_description_type":"Other"}]},"item_113_description_25":{"attribute_name":"注記","attribute_value_mlt":[{"subitem_description":"指導教員 : 小室孝","subitem_description_type":"Other"}]},"item_113_description_33":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"subitem_description":"text","subitem_description_type":"Other"}]},"item_113_description_34":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_113_dissertation_number_19":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第1201号"}]},"item_113_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.24561/00019567","subitem_identifier_reg_type":"JaLC"}]},"item_113_publisher_11":{"attribute_name":"出版者名","attribute_value_mlt":[{"subitem_publisher":"埼玉大学大学院理工学研究科"}]},"item_113_publisher_12":{"attribute_name":"出版者名（別言語）","attribute_value_mlt":[{"subitem_publisher":"Graduate School of Science and Engineering, Saitama University"}]},"item_113_record_name_8":{"attribute_name":"書誌","attribute_value_mlt":[{"subitem_record_name":"博士論文（埼玉大学大学院理工学研究科（博士後期課程））"}]},"item_113_text_31":{"attribute_name":"版","attribute_value_mlt":[{"subitem_text_value":"[出版社版]"}]},"item_113_text_36":{"attribute_name":"アイテムID","attribute_value_mlt":[{"subitem_text_value":"GD0001321"}]},"item_113_text_4":{"attribute_name":"著者 所属","attribute_value_mlt":[{"subitem_text_value":"埼玉大学大学院理工学研究科（博士後期課程）理工学専攻"}]},"item_113_text_5":{"attribute_name":"著者 所属（別言語）","attribute_value_mlt":[{"subitem_text_value":"Graduate School of Science and Engineering, Saitama University"}]},"item_113_version_type_32":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"ZAR, ZAR TUN","creatorNameLang":"en"},{"creatorName":"ザー, ザー トゥン","creatorNameLang":"ja-Kana"}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2022-06-15"}],"displaytype":"detail","filename":"GD0001321.pdf","filesize":[{"value":"277.7 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"GD0001321.pdf","objectType":"fulltext","url":"https://sucra.repo.nii.ac.jp/record/19598/files/GD0001321.pdf"},"version_id":"09eac47f-bfc4-44d2-9576-7d0d1899d609"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"Measuring Reflectance of Rough Surface Materials using Two Handheld Cameras","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Measuring Reflectance of Rough Surface Materials using Two Handheld Cameras","subitem_title_language":"en"}]},"item_type_id":"113","owner":"15","path":["1016"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2022-06-15"},"publish_date":"2022-06-15","publish_status":"0","recid":"19598","relation_version_is_last":true,"title":["Measuring Reflectance of Rough Surface Materials using Two Handheld Cameras"],"weko_creator_id":"15","weko_shared_id":-1},"updated":"2023-06-23T00:50:21.934815+00:00"}