Kensuke Tobitani

Chord character evaluation model based on harmoniousness: Application to music mood visualization interface

The chord, along with melody and rhythm, is one of the important elements in constituting music, but the cause of musics psychological effects are, for the most part, yet to be clarified. There are previous studies that define chord characters on the basis of the levels of dissonance, tension and modality, but there is not enough research to discuss psychological indexes which is called chords “brightness.” Therefore, in this study, in order to define a chord character evaluation based on harmoniousness, we propose a method for estimating the impression of brightness in chords. Evaluation experiments were performed in order to validate the proposed method. As a result, a strong correlation was found between the proposed degree of harmoniousness (H) and the results of psychological experiments. Furthermore, through the application of these results, an interface for representing musical mood through color was developed.

A Proposal of Evaluation Method for Balance of White Space in Calligraphy by Using Horizon View Camera

In this research, we paid attention to calligraphy education. In current calligraphy education in Japan, teachers evaluate character written by students and they teaches based on the written character. Professional in calligraphy can estimate writing process and balance of character which are important points for evaluation from written character by estimating movement of contact shape (contact face with a paper and a brush). But it takes a lot of time for students to learn correct writing process of character and balance of character in this education way. If teachers and students can know a movement of the contact shape, the calligraphy education will be more efficient. In case of taking an image of a brush by using a general camera setting, it is difficult to separate a character written by a black ink and a black brush to detect contact shape because both are black and the contact shap is hided under the brush. Therefore, we propose new camera setting system as Horizon View Camera (HVC) that is a special camera setting, and contact shapes can be detected and reconstructed by using this camera system. And, we evaluate balance of white space which means unwritten space on a paper for evaluation of a character. Correct white space in calligraphy is not just unwritten space but is influenced by movement of contact shape. Then by using HVC system, movement of contact shape which is difficult for amateur to estimate from written character can be detected dynamically and evaluation of white space in considering of influence of contact shape movement can be improved.

The Hierarchical Approach to the Semantic Differential Method: - The Equivocality of “Evaluation” Factor in the EPA Structure -

In this study, by proposing a model with a hierarchical relationship, we reconsidered the methodology utilizing the semantic differential technique. The proposed approach divided the subjective evaluation into the evaluative aspect and descriptive aspect, and identified the former as the upper layer expressing the level of value and the latter as a lower layer expressing the level of semantics. The subjective evaluation data was obtained in evaluation experiments measuring the value and semantics for the three-dimensional objects. Based on the obtained data, the proposed model was examined to see whether it can reflect individual differences and the influences of evaluation contexts that have been conventionally been treated as errors. Results showed that the proposed model expressed the influence of context and individual differences and suggested the need for a hierarchical approach beyond the framework of the semantic differential method, such as the conventional EPA structure.

Modeling the Relation between Skin Attractiveness and Physical Characteristics

There is a wide range of requirements for representing skin quality in various fields, such as computer graphics and cosmetics. However, accurate representation of skin quality is a difficult technical issue, because of the complex physical characteristics of skin and its constituent substances and structure. The objective of this study is to clarify the latent factors in the impression of skin, mainly skin attractiveness and to provide systematic modeling of the relation between impression and physical characteristics. This will not only enable intuitive representation of skin quality, but will also help elucidate the human recognition mechanism in relation to skin. To build the model, we first select words from those that are generally used to assess skin. Next, we study techniques capable of accurate skin representation, based on the physical characteristics of skin, and create CG images of skin. We then use the words and images to clarify the latent factors for forming a visual impression of skin. Finally, we conduct a regression analysis on the results obtained in the subjective evaluation test to build a systematic model to estimate the impression evoked, based on the skins physical characteristics. This makes it possible to estimate impressions from physical characteristics and conversely, to estimate those specific physical characteristics that contribute to a desired impression.

An evaluation of the relationship between impression and the physical properties of human skin

The visual expression of a surface quality of human skin is required in a wide range of fields, such as in cosmetics industry. It is much harder, however, to generate intuitively and accurately a computer graphics (CG) image of human skin that has a desired impression without professional knowledge and skills because of its complex physical properties. It is necessary to model the linkage between the visual impressions and physical properties of human skin in order to effectively determine parameters for the generation of CG images.

Analysis of BRDF/BTDF for the texture representation of woven fabrics based on the impression-evaluation model

To represent the texture of woven fabrics in computer graphics (CG), it is important to reveal the relation between their physical properties and the texture caused by them. For efficient representation of a realistic texture, a new layered model that links visual impressions with physical properties is required. Physical properties of woven fabrics include optical properties. They are reproduced by bidirectional reflectance distribution function (BRDF) and the bidirectional transmittance distribution function (BTDF). However, it is not easy to handle BRDF and BTDF because of the enormity of these data. Therefore, it is necessary to effectively integrate the dimensionality of BRDF and BTDF. In this paper, we propose the impression-evaluation model to link visual impressions with physical properties of woven fabrics. Moreover, to incorporate physical properties into the model, we investigate the main physical factors of reflection and transmission in woven fabrics using the multivariable analysis technique of principal component analysis (PCA) of BRDF and BTDF. As a result, three principal components of BRDF and two principal components of BTDF are obtained. Therefore, it becomes possible for inexpert people to make CG with realistic texture of woven fabrics more intuitively and easily by incorporating physical factors into the impression-evaluation model.

Lace curtain: interactive animation of transparent woven fabric based on microfacet BSDF model

Realistic and interactively generated computer graphics are needed in various fields, such as for CGI-animated movie and in education. To express the realistic appearance of various materials, it is important to represent the specific optical properties for each material.

A simulation of multilayer thin-film interference for pearl material preproduction

Visual simulation using computer graphics and virtual reality has come to be used recently in the production process to enhance the quality of materials and products. In this paper, we propose a simulation of multilayer thin-film interference for pearl material preproduction such as cosmetic development. Pearls manifest a very specific optical phenomenon caused by the multilayer thin-film structure, and most people have a common sense that pearls have a own beauty. Therefore, the expected merits of the simulation are not negligible. The author of this paper have reported a method of modeling and visualizing perfect sphere pearls. For a construction of the simulation system for a preproduction, it is necessary to apply the visualizing method to free-form surface, and consider the changes of blurring and interference color due to view angle which was not mentioned in the earlier research. As the results, we implemented the pearl visual simulation method as a plug-ins material shader of 3D computer graphics software MAYA and generated high-quality pearl and free-form surface 3D images with optical properties similar to pearl.

Lace curtain: rendering and animating woven cloth based on an impression-evaluation model

Woven fabric is frequently used in computer graphics. To express the realistic appearance of a woven fabric, it is important to represent its luster, transparency, and motion. In our previous study, we proposed a physically based BTDF model of woven cloth [Nomura et al. 2011] and a method of estimating the motion properties of woven cloth from subjective impression [Ishida et al. 2012]. However, for the further enhancement of the texture of materials in animations, it is necessary to construct a comprehensive impression model for the evaluation of woven cloth that includes the relationship between optics and motions, impressions and emotions that are evoked by the impressions. In this study, we propose an impression-evaluation model for the rendering of woven fabrics.

A simulation of pearl optical phenomena for cosmetic preproduction

In the area of materials development, preproduction using visual simulation has come to be considered essential. In this paper, we propose a simulation of pearl optical phenomena for cosmetic preproduction. Pearls manifest a very specific optical phenomenon caused by their multilayered thin-film structure, and most people have a common sense that pearls have a unique beauty. Therefore, the expected merits of the simulation for cosmetic preproduction are not negligible.