Eriko Aiba

Lace curtain: rendering animation of woven cloth using BRDF/BTDF: estimating physical characteristics from subjective impression

The need for rendering woven fabrics arises frequently in computer graphics. Woven fabrics have specific appearances such as luster and transparency. To express realistic appearance, however, it is necessary to set various parameters ad hoc by trained users. In our previous study, we proposed one solution for issues of luster and transparency by using a physically-based BTDF model of woven cloth on the basis of the GGX [Nomura et al. 2011]. Additionally, rendering fabric motion properties is also significant to enhance the texture of materials in animations [Faure et al. 2009]. In this study, we propose a new method to render woven fabrics which have both realistic appearance and motion.

An Optimal Text/Background Color Combination of LED Information Boards for Visibility Improvement Based on Psychological Measurements

In this study, conspicuity and readability of the text on light-emitting diode (LED) information boards were evaluated by psychological experiments, and the influences of color combinations of text / background, luminance, and shadow were evaluated quantitatively. In recent years, LED boards have been able to display full-color images, and they have many functions to highlight text. Therefore, it is assumed that the LED board ability to function may be reduced depending on the way it is used. We investigated the relationship of color combinations of text and background, luminance, and shadow to conspicuity and readability to evaluate ease and efficiency of information communication via the LED board. We found that (1) the size of the area with high luminance affected conspicuity, (2) the difference of luminance of the part adjacent to the text/background affected readability, and (3) shadow affected both conspicuity and readability. Furthermore, trade-off between them was confirmed.

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.

Identification of factors related to the enhancement of image-quality for subjective image-quality assessment model based on psychological measurement

The purpose of this study is to identify the physical factors affecting image-quality for a comprehensive enhancement in subjective image-quality assessment by human being. In recent years, digital cameras have become extremely popular because they enable image recording with very high fidelity and are affordably priced. However, in subjective image-quality assessment by human, one does not always consider that images with high fidelity are of high quality. In this study, a psychological experiment was performed as the first step to develop a subjective image-quality assessment model that considers kansei of human being by using conjoint method. We particularly focused on the identification of physical factors without depending on a scene. The results of this experiment showed that “luminance” and “contrast” may contribute to an enhancement in the image-quality assessment, regardless of the type of scene used. It was also suggested that human memory, in which the colors preferred by the individual are retained, also plays a major role in a subjective image-quality assessment.

An electromyographic study of left hand between experts and novices in violin playing

We recently recorded string clamping force on the violin during simple (without vibrato) tone production by expert violinists. The results of our studies showed that the peak force exceeded 4.5 N at slow tempi, which decreased to 1.7 N at fast tempi. However, subjective assessment of playing effort indicated an opposite trend; the players felt that playing at faster tempi was more strenuous. We also measured muscular activity along with finger kinematics. We found that the mean left forearm muscle activity increased with tempo. The findings suggest that the speed of finger movement is more related to the arm and hand discomfort when playing a violin, as compared to clamping force. In the present study, we investigated the expert-novice difference in the nature of the string clamping force and related muscles in the left hand and arm while playing a violin. Information regarding the string clamping force and left hand muscle activity can help in teaching novices about the magnitude and timing of the approp...

String-pressing force of Japanese Koto

The koto is a traditional Japanese stringed musical instrument and is similar to the zither. The koto typically has 13 strings and is played by plucking the strings using three fingers (thumb, index, and middle fingers) with picks. Each string is strung over a movable bridge, and the support point can be changed by adjusting the position of the bridge. As the distance between the support point and the right end of the string determines a pitch, the koto is tuned by adjusting the bridge position. In addition, players can change the pitch by pressing the string with their left hand. This technique is called oshide and it is important but difficult to apply accurately for koto players. The subjective difficulties of oshide change depending on the position of the strings (on the near or far side of a player’s body), string’s material (silk or polyester), condition (old or new) of the string, and so on. In order to ensure good-quality performance, expert koto players modify their string-pressing manner. Howeve...

Music signal processing by the human brains: Studies on the strategies used by professional pianists to efficiently sight-read music

The human brain is an ingenious signal processing system. When musicians play instruments, their brains must process a huge amount and various types of information in parallel. Particularly, the sight-reading of piano music requires the processing of an enormous amount of information as piano music includes many chords and is written on the great staff (or grand staff). Pianists have to read the score, interpret the music, search for the keys to be played while planning the motions of fingers, and control their fingers. In addition, they must adjust the sound intensity and usage of the sustaining pedal according to the output sound. All these are performed simultaneously and successively. The sensory information or signals to be processed include many different modalities, such as visual, auditory, tactile, and motion sensing. In order to complete this complicated task, it is important that the pianists efficiently process this information. In this presentation, I introduce our experimental studies invest...

Music Memory Following Short-term Practice and Its Relationship with the Sight-reading Abilities of Professional Pianists

This study investigated the relationship between the ability to sight-read and the ability to memorize a score using a behavioral experiment. By measuring the amount of memorization following short-term practice, we examined whether better sight-readers not only estimate forthcoming notes but also memorize musical structures and phrases with more practice. Eleven pianists performed the music first by sight-reading. After a 20-minute practice, the participants were asked to perform from memory without any advance notice. The number of mistakes was used as an index of performance. There were no correlations in the numbers of mistakes between sight-reading and memory trial performance. Some pianists memorized almost the entire score, while others hardly remembered it despite demonstrating almost completely accurate performance just before memory trial performance. However, judging from the participants’ responses to a questionnaire regarding their practice strategies, we found auditory memory was helpful for memorizing music following short-term practice.

Relationship between Musical Characteristics and Temporal Breathing Pattern in Piano Performance

Although there is growing evidence that breathing is modulated by various motor and cognitive activities, the nature of breathing in musical performance has been little explored. The present study examined the temporal breath pattern in piano performance, aiming to elucidate how breath timing is related to musical organization/events and performance. In the experiments, the respiration of 15 professional and amateur pianists, playing 10 music excerpts in total (from four-octave C major scale, Hanons exercise, J. S. Bachs Invention, Mozarts Sonatas, and Debussys Clair de lune), was monitored by capnography. The relationship between breathing and musical characteristics was analyzed. Five major results were obtained. (1) Mean breath interval was shortened for excerpts in faster tempi. (2) Fluctuation of breath intervals was reduced for the pieces for finger exercise and those in faster tempi. Pianists showing large within-trial fluctuation also exhibited large inter-excerpt difference. (3) Inter-trial consistency of the breath patterns depended on the excerpts. Consistency was generally reduced for the excerpts that could be performed mechanically (i.e., pieces for finger exercise), but interestingly, one third of the participant showed consistent patterns for the simple scale, correlated with the ascending/descending sequences. (4) Pianists tended to exhale just after the music onsets, inhale at the rests, and inhibit inhale during the slur parts. There was correlation between breathing pattern and two-voice polyphonic structure for several participants. (5) Respiratory patterns were notably different among the pianists. Every pianist showed his or her own characteristic features commonly for various musical works. These findings suggest that breathing in piano performance depends not only on musical parameters and organization written in the score but also some pianist-dependent factors which might be ingrained to individual pianists.

Comparison of Different Grinding Sound During Metallographic Preparation

The carburizing process requires metallurgical inspection by means of ground metallurgical mounts. Grinding process for a metallurgical mount is an important process. In this study, we investigate the difference in the outcome of the sound during the grinding process between an expert and a non-expert execution. We aim to identify the evaluation criteria in grinding technique based on the sound information, in order to establish more efficient training method for acquiring the grinding techniques for non-expert inspectors. As a result, we found the factor in the sound that are essential for the efficient grinding.Copyright