Use of multiple light sources to enhance the resolution of point light source displays.

The point light sources (PLSs) of integral imaging displays have a wide depth range; however, the resolution is very low. We developed resolution-enhanced PLS displays using multiple light sources that create extra PLSs in the PLS plane. Given aberrations in the lens arrays, the PLSs initially appeared on planes and at distances that differed from the theoretical values. We thus determined the distances between adjacent light sources that compensated for the aberrations. Experimentally, our method enhanced the resolution fourfold compared to that of a conventional PLS display in both vertical and horizontal directions. Our approach allows facile compensation of lens array aberrations and is applicable to 3D displays.

Three-dimensional see-through augmented-reality display system using a holographic micromirror array.

It is difficult to find the micromirror array with desired specifications for augmented-reality displays, and the custom fabricating methods are complicated and unstable. We propose a novel, to our knowledge, three-dimensional see-through augmented-reality display system using the holographic micromirror array. Unlike the conventional holographic waveguide-type augmented-reality displays, the proposed system utilizes the holographic micromirror array as an in-coupler, without any additional elements. The holographic micromirror array is fabricated through the simple, effective, and stable method of applying the total internal reflection-based hologram recording using a dual-prism. The optical mirror and microlens array are set as references, and the specifications can be customized. It reconstructs a three-dimensional image from a displayed elemental image set without using any additional device, and the user can observe a three-dimensional virtual image while viewing the real-world objects. Thus, the principal advantages of the existing holographic waveguide-type augmented-reality system are retained. An optical experiment confirmed that the proposed system displays three-dimensional images exploiting the augmented-reality system simply and effectively.

Vertical viewing angle enhancement for the 360 degree integral-floating display using an anamorphic optic system.

We propose a 360 degree integral-floating display with an enhanced vertical viewing angle. The system projects two-dimensional elemental image arrays via a high-speed digital micromirror device projector and reconstructs them into 3D perspectives with a lens array. Double floating lenses relate initial 3D perspectives to the center of a vertically curved convex mirror. The anamorphic optic system tailors the initial 3D perspectives horizontally and vertically disperse light rays more widely. By the proposed method, the entire 3D image provides both monocular and binocular depth cues, a full-parallax demonstration with high-angular ray density and an enhanced vertical viewing angle.

Viewing angle enhanced integral imaging display using two elemental image masks.

A viewing angle enhanced integral imaging display using two elemental image masks is proposed. In our new method, rays emitted from the elemental images are directed by two masks into corresponding lenses. Due to the elemental image guiding of the masks, the number of elemental images for each integrated image point is increased, enhancing the viewing angle. The experimental result shows that the proposed method exhibits two times larger viewing angle than the conventional method with the same lens array.

Fresnel and Fourier hologram generation using orthographic projection images.

A novel technique for synthesizing a hologram of three-dimensional objects from multiple orthographic projection view images is proposed. The three-dimensional objects are captured under incoherent white illumination and their orthographic projection view images are obtained. The orthographic projection view images are multiplied by the corresponding phase terms and integrated to form a Fourier or Fresnel hologram. Using simple manipulation of the orthographic projection view images, it is also possible to shift the three-dimensional objects by an arbitrary amount along the three axes in the reconstruction space or invert their depths with respect to the given depth plane. The principle is verified experimentally.

View image generation in perspective and orthographic projection geometry based on integral imaging.

A novel technique generating arbitrary view images in perspective and orthographic geometry based on integral imaging is proposed. After capturing three-dimensional object using a lens array, disparity estimation is performed for the pixels at the selected position of each elemental image. According to the estimated disparity, appropriate parts of elemental images are mapped to synthesize new view images in perspective or orthographic geometry. As a result, the proposed method is capable of generating new view images at arbitrary positions with high resolution and wide field of view.