Tohru Kawakami

Speckle reduction mechanism in laser rear projection displays using a small moving diffuser.

Recently, a practical method of speckle reduction in laser rear projection displays that uses an optical system with a small moving diffuser has attracted much attention. In this paper, a model of the speckle generation and reduction mechanism in the system is presented. We investigated the speckle, focusing on the physical aspects of its generation, rather than treating it statistically. We found that the granularity of the speckle patterns generated by the small diffuser corresponded to the size of the coherent regions on the projection screen. This determined the efficiency of the speckle reduction when the small diffuser was rotated.

Multiple directional viewing projection display based on the incident-angle-independent, diffusion-angle-quantizing technology

We have devised an incident-angle-independent, quantized-diffusion-angle screen and have realized a multiple directional viewing projection display system using double-side lenticular lens. Our display system has advantages of easy alignment for multiple projectors, and capability of multiple different images simultaneously according to viewing angle at any distance from the screen.

Analysis of speckle‐reduction performance in a laser rear‐projection display using a small moving diffuser

— Recently, a practical method of speckle reduction in laser rear-projection displays that uses an optical system with a small moving diffuser has attracted much attention. In this paper, a model of the speckle generation and reduction mechanism in the system is presented. Speckle in the system was investigated, focusing on the physical aspects of its generation rather than treating it statistically, and it was found that the granularity of the speckle patterns generated by the small diffuser corresponded to the size of the coherent regions on the projection screen. This determined the efficiency of the speckle reduction when the small diffuser was rotated. By using these results, a method to estimate the performance of speckle reduction on the system was developed.

High‐resolution autostereoscopic 3‐D projection display with a space‐dividing iris‐plane shutter

— A high-resolution autostereoscopic 3-D projection display with a polarization-control space dividing the iris-plane liquid-crystal shutter is proposed. The polarization-control iris-plane shutter can control the direction of stereo images without reducing the image quality of the microdis-play. This autostereoscopic 3-D projection display is 2-D/3-D switchable and has a high resolution and high luminance. In addition, it has no cross-talk between the left and right viewing zones, a simple structure, and the capability to show multi-view images.

MulDiRoH: A Multi-View Human Representation System Using a QDA Screen With Multiple Cameras

In this paper, we have developed a human representation system we call “MulDiRoH.” It consists of a multiview display that uses a QDA screen and multiple cameras. The QDA screen has a large, wide viewing area that enables observers to comfortably watch the display. It is also convenient in that accurate projector orientation is unnecessary; this makes easy system construction possible. In this paper, we describe the MulDiRoH system and propose a “Tiled Image Method” to achieve shorter projection distance with it and a “Perspective Transform Method” to correct views obtained with it.

Large High-Definition Multiview Display System Capable of Controlling Observation Area

We developed a large high-definition multiview projection display configured from newly developed double-sided lenticular lens, a Fresnel lens, and multiple projectors. The system projects magnified images of each projectors iris side by side using a Fresnel lens, which minimizes the crosstalk between the images in adjacent areas and creates a broad observation area with highly uniform in-plane brightness. In addition, by using an inclined screen, we developed a method to evaluate the observation area of the multiview display. The characteristics of the proposed multiview display are the easily adjustable projector arrangement and the broad observation area without crosstalk between images in adjacent areas. The proposed multiview display is expected to be useful in future teleconference and digital signed systems.

High-Resolution Multi-View Projection Display With a Quantized-Diffusion-Angle Screen

In this paper, we have devised a novel projection screen using a double-sided lenticular lens with a diffusion angle range quantized by the incident light angle and a constant diffusion light intensity, independent of the angle of the incident light. We developed high-resolution multi-view projection display using a novel projection screen and multiple projectors. Our display system has the advantage of making it easy to align multiple projectors, and the capability of simultaneously projecting multiple different images at different viewing angles at any distance from the projection screen.

MulDiRoH: a human representation system with multi-view display using a QDA screen

In the area of teleconference systems, it is very important to have a function to enable participants to viscerally understand where a remote participant is actually looking at [Jones et al. 2009] [Feldmann et al. 2010]. A multi-view display using a parallax barrier that achieves such a function has been proposed [Takaya2007]. However, three problems have emerged in these previous studies. The first is that the systems are difficult to construct. The second is that the number of observers decreases. The third is that the observation area is very shallow.

360-degree screen-free floating 3D image in a crystal ball using a spatially imaged iris and rotational multiview DFD technologies

A rotational multiview depth-fused 3D (DFD) display and 360-deg displaying optics using a spatially imaged iris method are proposed to realize a 360-deg 3D image. This method enables displaying clear floating images in a crystal ball. Its symmetric optics provide clear and natural 360-deg images with smooth motion parallax in horizontal and vertical directions using the directional selectivity of a spatially imaged iris method and natural 3D images of a rotational multiview DFD display.

Luminance profile control method using gradation iris for autostereoscopic 3D displays

A precise control method of angular luminance distribution of viewing zone using a Alter with gradation in transmittance in an iris of a projector is proposed for autostereoscopic 3D display with smooth motion parallax.