Compact self-interference incoherent digital holographic camera system with real-time operation.

The video recording-capable compact incoherent digital holographic camera system is proposed. The system consists of the linear polarizer, convex lens, geometric phase lens, and the polarized image sensor. The Fresnel hologram is recorded by this simple configuration in real time. The system parameters are analyzed and evaluated to record a better-quality hologram in a compact form-factor. The real-time holographic recording and its digitally reconstructed video playback are demonstrated with the proposed system.

Achromatic phase shifting self-interference incoherent digital holography using linear polarizer and geometric phase lens.

A simple Fresnel-type self-interference incoherent digital holographic recording system is proposed. The main part of the system consists of the two linear polarizers and geometric phase lens. The geometric phase lens is employed as a polarization selective common-path interferometer. One of the polarizers is rotated by the motor and serves as a phase-shifter with the geometric phase lens, to eliminate the bias and twin image noise. A topological phase is obtained by the relative angle between the polarizer and geometric phase lens. Since this phase shifting method does not depend on the change of the optical path length, the phase shifting performance is almost constant in the broad spectral range. Using the proposed achromatic phase shifting method, a simultaneous three-color phase shifting digital hologram recording under the incoherent light source is demonstrated.

Self-interference digital holography with a geometric-phase hologram lens.

Self-interference digital holography (SIDH) is actively studied because the hologram acquisition under the incoherent illumination condition is available. The key component in this system is wavefront modulating optics, which modulates an incoming object wave into two different wavefront curvatures. In this Letter, the geometric-phase hologram lens is introduced in the SIDH system to perform as a polarization-sensitive wavefront modulator and a single-path beam splitter. This special optics has several features, such as high transparency, a modulation efficiency up to 99%, a thinness of a few millimeters, and a flat structure. The demonstration system is devised, and the numerical reconstruction results from an acquired complex hologram are presented.

Optical defocus noise suppressing by using a pinhole-polarizer in Fresnel incoherent correlation holography.

We propose the method that suppresses the defocus noise optically in the Fresnel incoherent correlation holographic system using a pinhole-polarizer (PP), which is made by punching a pinhole on the linear polarizer. The system configuration of this suggestion is based on the original system with optical-sectioning capability, which is realized by presenting the phase-pinhole on the phase-only spatial light modulator. In our system, the phase-pinhole is replaced with a PP. The replaced component is no longer programmable yet provides an affordable, simple, and light-efficient system configuration. The feasibility of the system with the PP is analyzed and demonstrated.

Real object pickup method of integral imaging using offset lens array.

We propose the pickup system of integral imaging using the offset lens array (OLA), which is a useful optical component for both the pickup and display processes. The main purpose of our system is resolving the pseudoscopic image problem of integral imaging. Also, the flipped image of integral imaging that has the wrong perspective information can be removed by adding an external barrier in the display process. In this paper, the above properties are explained in detail, and the experimental results to verify the feasibility of the proposed system are presented. We are certain that our system can also be applied to other various pickup systems based on integral imaging.

Analysis on image expressible region of integral floating.

We define the image expressible region where three-dimensional (3D) images can be reconstructed in an integral floating display using ray distribution information. Here, the image expressible and viewing regions of the integral floating system, defined using ray distribution based on ray optics, are analyzed to resolve an image-cropping problem known as the viewing window that is due to the virtual aperture. Two experiments for verifying the image expressible and viewing regions are performed, and the results are presented. The obtained analysis is useful to maximize the viewing properties of integral floating.

Measurement of accommodation response of human eye to integral floating display.

The dioptric responses of human eyes to floating images at different depths reconstructed by an integral floating display are measured with an open-field autorefractor and analyzed according to observer recognition of the accommodation depth cue. Two targets are randomly presented approximately 1.75 D from the observers and have a separation of 0.15 D, corresponding to approximately 5 cm. Two subjects participate, and over 500 responses are measured during each experimental trial. The frequency distribution profiles of the responses to targets at different locations are obtained and analyzed. The results confirm that the subjects focused on the floating targets and not on the surface of the optical component. In this paper, an analysis of the separation between the peaks of the frequency distribution profiles is presented that confirms that the integral floating display could induce the accommodation response to provide the corresponding depth stimulus.

Tiled integral floating display without occlusion effect using an offset lens array and a perpendicular barrier.

Low resolution and narrow viewing angle are common problems for most of the existing autostereoscopic display systems. Although integral imaging is among the promising candidates for future autostereoscopic display, it is not yet free from the above bottlenecks. In this paper, a new technique to enhance the picture quality of a three-dimensional image using an offset lens array is proposed. The proposed system is suitable to realize a tiled integral floating display with high pixel density, while it also increases the viewing angle to match all of the optical devices in a single display unit. The proposed scheme was also verified with experimental results.

Compensation of elemental image using multiple view vectors for off-axis integral floating system.

A novel method is proposed to compensate the distortion caused by the off-axis structure in integral floating with a concave mirror. The proposed method of this paper can generate the elemental image that is integrated into the multiple predistortion images for the corresponding multiview directions, which cannot be performed by the predistortion method using a single-view vector. The fundamental concept of the proposed method is that the predistortion images can be generated for more than two view vectors, which are defined by each set of corresponding elemental lens and subimage, and captured onto the subimage. In addition, the subimage can be divided into the several segments to increase the number of view vectors, so that the predistortion images generated by more view vectors can enhance the degree of compensation. The proper number of the view vectors per subimage is discussed and analyzed based on the small-angle approximation. Experiments to verify the feasibility of the proposed method are performed.