박재형 교수

Recently developed integral imaging techniques are reviewed. Integral imaging captures and reproduces the light rays from the object space, enabling the acquisition and the display of the three-dimensional information of the object in an efficient way. Continuous effort on integral imaging has been improving the performance of the capture and display process in various aspects, including distortion, resolution, viewing angle, and depth range. Digital data processing of the captured light rays ca

Computer-generated holography (CGH) is a crucial technique in preparing contents for holographic three-dimensional displays. In this paper, the recent progress in the CGH techniques is reviewed, covering the point-cloud-, light-ray-field-, layer-, and polygon-based techniques.

We describe and compare two methods of displaying autostereoscopic three-dimensional images by integral photography. One method is to display the image in front of the lens array, and the other method is to display the image behind the lens array. We compare and discuss these two methods from the viewpoints of lateral resolution, depth resolution, and viewing angle. We also discuss the effect of the optical parameter difference in the pickup and display.

Near-eye displays are the main platform devices for many augmented reality (AR) and virtual reality (VR) applications. As a wearable device, a near-eye display should have a compact form factor and be lightweight. Furthermore, a large field of view and sufficient eyebox are crucial for immersive viewing conditions. Natural three-dimensional (3D) image presentation with proper focus cues is another requirement that enables a comfortable viewing experience and natural user interaction. Finally, in

We propose an optical see-through holographic near-eye-display that can control the depth of field of individual virtual three-dimensional image and replicate the eyebox with dynamic steering. For optical see-through capability and eyebox duplication, a holographic optical element is used as an optical combiner where it functions as multiplexed tilted concave mirrors forming multiple copies of the eyebox. For depth of field control and eyebox steering, computer generated holograms of three-dimen

A depth-enhanced three-dimensional-two-dimensional convertible display that uses a polymer-dispersed liquid crystal based on the principle of integral imaging is proposed. In the proposed method, a lens array is located behind a transmission-type display panel to form an array of point-light sources, and a polymer-dispersed liquid crystal is electrically controlled to pass or to scatter light coming from these point-light sources. Therefore, three-dimensional-two-dimensional conversion is accomp

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

Stereo matching, a technique for acquiring depth information from many planar images obtained by several cameras, was developed several decades ago. Recently a novel depth-extraction technique that uses a lens array instead of several cameras has attracted much attention because of the advantages offered by its compact system configuration. We present a novel depth-extraction method that uses a lens array consisting of vertically long rectangular lens elements. The proposed method rearranges the

Integral imaging has been attracting much attention recently for its several advantages such as full parallax, continuous view-points, and real-time full-color operation. However, the thickness of the displayed three-dimensional image is limited to relatively small value due to the degradation of the image resolution. In this paper, we propose a method to provide observers with enhanced perception of the depth without severe resolution degradation by the use of the birefringence of a uniaxial cr

A three-dimensional optical correlator using a lens array is proposed and demonstrated. The proposed method captures three-dimensional objects using the lens array and transforms them into sub-images. Through successive two-dimensional correlations between the sub-images, a three-dimensional optical correlation is accomplished. As a result, the proposed method is capable of detecting out-of-plane rotations of threedimensional objects as well as three-dimensional shifts.

In 2019, the device performances of the display technologies were largely advanced by the development of new materials and of the device architecture and driving scheme. The recent progress in the areas of virtual reality (VR), augmented reality (AR), quantum dot light-emitting diode (QLED), and organic light-emitting diode (OLED) is comprehensively summarized and discussed in this paper.

In a three-dimensional display scheme based on integral imaging, the mismatch of the system parameters between the pickup and display systems or between the display systems is an important issue from a practical point of view. In this paper, we propose a method that provides excellent flexibility to the integral imaging system parameters and display conditions. In the proposed method, elemental images obtained in the pickup process are digitally analyzed and full three-dimensional information of

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 gene