Projection Mapping (PM) is a technology that projects images onto the surfaces of physical objects, allowing multiple users to share an augmented reality experience without special devices. However, its practical use has been constrained by the need for dark environments to ensure high-quality projection. To overcome this "dark-room constraint," we propose a novel target-excluding lighting method that selectively illuminates the surrounding environment while avoiding the PM target. Our system achieves light-field illumination by combining an LED display panel with an optimized aperiodic lens array. The key contributions include a compact form factor that provides a large effective light source area, reproducing natural soft shadows comparable to typical lighting, while maintaining the spatial controllability needed to precisely avoid the target. We also introduce a computational technique for optimizing aperiodic lens placement to suppress undesired dark spots caused by crosstalk, and efficient methods for computing LED luminance patterns that enable dynamic PM. Experiments with a prototype system demonstrate that our approach achieves high-contrast PM even in bright environments.

Projection mapping (PM) enables augmented reality (AR) experiences without requiring users to wear head-mounted displays and supports multi-user interaction. It is regarded as a promising technology for a variety of applications in which users interact with content superimposed onto augmented objects in tabletop workspaces, including remote collaboration, healthcare, industrial design, urban planning, artwork creation, and office work. However, conventional PM systems often suffer from projection shadows when users occlude the light path. Prior approaches employing multiple distributed projectors can compensate for occlusion, but suffer from latency due to computational processing, degrading the user experience. In this research, we introduce a synthetic-aperture PM system that uses a significantly larger number of projectors, arranged densely in the environment, to achieve delay-free, shadowless projection for tabletop workspaces without requiring computational compensation. To address spatial resolution degradation caused by subpixel misalignment among overlaid projections, we develop and validate an offline blur compensation method whose computation time remains independent of the number of projectors. Furthermore, we demonstrate that our shadowless PM plays a critical role in achieving a fundamental goal of PM: altering material properties without evoking projection-like impression. Specifically, we define this perceptual impression as "sense of projection (SoP)" and establish a PM design framework to minimize the SoP based on user studies.

Projection mapping (PM) is a technique that enhances the appearance of real-world surfaces using projected images, enabling multiple people to view augmentations simultaneously, thereby facilitating communication and collaboration. However, PM typically requires a dark environment to achieve high-quality projections, limiting its practicality. In this paper, we overcome this limitation by replacing conventional room lighting with heterogeneous projectors. These projectors replicate environmental lighting by selectively illuminating the scene, excluding the projection target. Our contributions include a distributed projector optimization framework designed to effectively replicate environmental lighting and the incorporation of a large-aperture projector, in addition to standard projectors, to reduce high-luminance emitted rays and hard shadows-undesirable factors for collaborative tasks in PM. We conducted a series of quantitative and qualitative experiments, including user studies, to validate our approach. Our findings demonstrate t hat our projector-based lighting system significantly enhancesthe contrast and realism of PM results even under e nvironmental lighting compared to typical lights. Furthermore, our method facilitates a substantial shift in the perceived color mode from the undesirable aperture-color mode, where observers perceive the projected object as self-luminous, to the surface-color mode in PM.

Our research is related to the development of an anthropomorphic saxophonist robot which reproduced the human organs involved during the saxophone playing. This research approach aims in understanding the human motor control from an engineering point of view and enabling the communication between humans and robots in musical terms. In a previous research, we have presented the Waseda Saxophonist Robot No. 2 (WAS-2) which improved the design of the lip and finger mechanisms. In addition, a feed-forward air pressure with dead-time compensation and an overblowing correction controller were implemented. However, the range of pressure was too limited to reproduce dynamic effects of the sound (i.e. decrescendo, etc.), a delay on the response of the finger mechanism was detected (due to the use of a wire-driven mechanism) and deviations on the pitch during the saxophone playing were observed. Therefore; in this paper, we present the Waseda Saxophonist Robot No. 2 Refined (WAS-2R). In particular the shape of the oral cavity has been re-designed to increase the sound pressure range and potentiometers were embedded on the fingers to reduce the dynamic delay response of the wire-driven mechanism. In addition, a Pressure-Pitch Controller has been implemented to reduce the deviation of the sound pitch by implementing a feedback error learning algorithm for a Multiple-Input Multiple-Output system. A set of experiments were proposed to verify the effectiveness of the re-designed mechanisms and the improved control strategy. From the experimental results, we could confirm the improvements to extend the sound pressure range to reproduce the decrescendo effect, to reduce the response delay from the finger mechanism as well as the deviations on the sound pitch.

Since 2007, the research on the anthropomorphic saxophonist robot at Waseda University aims in understanding the human motor control from an engineering point of view as well as an approach to enable the interaction with musical partners. As a result of our research, last year we have introduced the Waseda Saxophonist Robot No. 1 (WAS-1), composed of 15-DOFs that reproduced the lips (1-DOF), tonguing (1-DOF), oral cavity, lungs (2-DOF) and fingers (11-DOFs). However, even that the mouth mechanism of WAS-1 was useful in order to adjust the pitch of the saxophone sound, the range of sound pressure was too narrow. Thus, no dynamic effects of the sound can be reproduced (i.e. crescendo and decrescendo). Moreover, the finger mechanism was designed only to play from C3-C#5. On the other hand, a cascade feedback control system has been implemented in the WAS-1; however, a considerable delay in the attack time to reach the desired air pressure was detected. Therefore, in this paper, the Waseda Saxophone Robot No. 2 (WAS-2) which is composed by 22-DOFs is detailed. The lip mechanism of WAS-2 has been designed with 3-DOFs to control the motion of the lower, upper and sideway lips. In addition, a human-like hand (16 DOF-s) has been designed to enable to play all the keys of the instrument. Regarding the improvement of the control system, a feed-forward control system with dead-time compensation has been implemented to assure the accurate control of the air pressure. A set of experiments were carried out to verify the mechanical design improvements and the dynamic response of the air pressure. As a result, the range of sound pressure has been increased and the proposed control system improved the dynamic response of the air pressure control.

Since 2007, our research is related to the development of an anthropomorphic saxophonist robot, which it has been designed to imitate the saxophonist playing by mechanically reproducing the organs involved for playing a saxophone. Our research aims in understanding the motor control from an engineering point of view and enabling the communication. In a previous paper, the Waseda Saxophone Robot No. 2 (WAS-2) which is composed by 22-DOFs has been presented. Moreover, a feedback error learning with dead time compensation has been implemented to control the air pressure of the robot. However, such a controller couldn't deal with the overblowing effects (unsteady tones) that are found during a musical performance. Therefore; in this paper, the implementation of an Overblowing Correction Controller (OCC) has been proposed and implemented in order to assure the steady tone during the performance by using the pitch feedback signal to detect the overblowing condition and by defining a recovery position (off-line) to correct it. Moreover, a saxophone sound evaluation function (sustain phase) has been proposed to compare the sound produced by human players and the robot. A set of experiments were carried out to verify the improvements on the musical performance of the robot and its sound has been quantitatively compared with human saxophonists. From the experimental results, we could observe improvements on the pitch (correctness) and tone stability.

The research on the development of musical performance robots has been particularly intensified on the last decades. In fact, the development of anthropomorphic robots able of playing musical instruments have been served as a mean for understanding the human motor control from an engineering point of view as well as understanding how to enable the communication between human and robots from an emotional point of view. In particular, our research aims in the development of an anthropomorphic saxophonist robot which is able not only of performing a musical score; but also to interact with other musical performance robots (i.e. Waseda Flutist Robot) at the emotional level of perception. In this year, we have focused on the mechanical design of an anthropomorphic robot Waseda Saxophonist Robot No. 1 (WAS-1); which has been designed for playing an alto saxophone. WAS-1 has a total of 15-DOFs which mechanically reproduces the following organs involved during the saxophone playing: lips (1-DOF), tongue (1-DOF), oral cavity, lungs (air pump: 1-DOF and air valve: 1-DOF) and fingers (11-DOFs). In order to verify the effectiveness of the production of sound, a set of experiments have been proposed. In particular, the characteristics of air flow-pressure, level of mechanical noise, and the ripple effect ratio are presented. Finally, a qualitative evaluation of the sound produced by WAS-1 is presented and discussed. From the experimental results, we have confirmed the effectiveness of the proposed mechanisms to produce the saxophone sound.

During several decades, the research at Waseda University has been focused on developing anthropomorphic robots able of performing musical instruments. More recently, the authors have succeeded in developing a human-like robot able of playing the alto saxophone. As a result of our research efforts, the Waseda flutist robot WF-4RIV and the Waseda saxophonist robot WAS-1 have been designed to reproduce the human player performance. Therefore, as a long-term goal, we are proposing to enable the interaction between musical performance robots (i.e. robots orchestra). Such approach may enable us not only to propose new ways of musical expression, but also we may contribute to the better understanding of some of the mechanisms that enable the communication of humans in musical terms. In general terms, the communication of humans within an orchestra is a special case of conventional human social behavior. Rhythm, harmony and timbre of the music played represent the emotional states of the musicians. Of course, we are not considering a musical performance robot (MPR) just as a mere sophisticated MIDI instrument. Instead, its human-like design and the integration of perceptual capabilities may enable to act on its own autonomous initiative based on models which consider its own physical constrains. Due to the complexity of our long-term goal, in this paper, we are presenting our first steps towards enabling the interaction between musical performance robots. In particular, the details of the musical performance control systems are detailed. Thanks to the use of MIDI data, we performed preliminary experiments to enable a duet performance between the WF-4RIV and the WAS-1. We expect in the future; as a result of our research, we may enable a single anthropomorphic robot to perform different kinds of woodwind instruments as well as enable to interact at with level of perceptual capabilities (like human does).