Jung-Young Son

Methods for Displaying Three-Dimensional Images

The essential components of generating three-dimensional (3-D) images are defined, and various methods of creating each of the components are explained. The components are image acquisition, image multiplexing and processing, and display mechanisms. For image acquisition, transforming, synthesizing based on disparity, voxel and wavefront deformation, and sampling and photographing methods are used. For multiplexing, time, spatial, and spatiotemporal, and for processing, chirping, layering, and pixel cell based multiview image arrangement methods are used. The display mechanisms are classified into projection, contact,and scanning types depending on their means of displaying images. From these methods, 3-D images with real volume, with parallax only and with psychologically induced depth sense can be generated. The display mechanisms have another important mission of creating viewing zones. For this purpose, all 3-D imaging methods employ a special form of optics or mechanisms complying with their image multiplexing schemes. These optics and mechanisms are essential in realizing 3-D imaging systems but at the same time they provide many unfriendly and uncomfortable effects to viewers, and also impose some functional limitations.

Viewing zones in three-dimensional imaging systems based on lenticular, parallax-barrier, and microlens-array plates

The viewing zone of autostereoscopic imaging systems that use lenticular, parallax-barrier, and microlens-array plates as the viewing-zone-forming optics is analyzed in order to verify the image-quality differences between different locations of the zone. The viewing zone consists of many subzones. The images seen at most of these subzones are composed of at least one image strip selected from the total number of different view images displayed. These different view images are not mixed but patched to form a complete image. This image patching deteriorates the quality of the image seen at different subzones. We attempt to quantify the quality of the image seen at these viewing subzones by taking the inverse of the number of different view images patched together at different subzones. Although the combined viewing zone can be extended to almost all of the front space of the imaging system, in reality it is limited mainly by the image quality.

Three-Dimensional Imaging, Visualization, and Display

This book will describe recent developments, as well as the prospects and challenges facing 3D moving picture systems and devices, including binocular, multi-view, holographic, and image reproduction techniques. Optical systems, display instruments, and image capture techniques will be covered. The online supplement will include full color movies of experiments describing recent advances in 3D movies. This is the first state-of-the-art book on this subject that efficiently integrating the background material with new advances and applications and includes movies of 3D display systems.

MoirÉ Minimization Condition in Three-Dimensional Image Displays

A moirÉ minimization condition is found analytically for the contact-type three-dimensional (3-D) imaging systems by approximating 3-D displays as four superposed sine gratings. Finding maximization conditions for two-dimensional (2-D) waves in this structure provides minimization of moirÉs. The global extremum was found at a certain angle which does not depend on the period. Experiments confirm the analytical findings. Practical advantage of using that angle is in its wide areas of applications: 3-D displays can be made to have almost invisible moirÉs with using this angle without regards to other specific parameters like pixel size and pitch of the screen.

About a MoirÉ-Less Condition for Non-Square Grids

The moire-less condition is found for non-square grids. The exact solution is found in form of a quartic equation depending on the geometric parameter. The root gives the optimal angle for minimized moires. The approximate solution is also found as well as the upper limit for residual moires. The proximity of the two solutions is proven. Experiments confirm the theoretical findings. The results can be used for minimizing moires in display devices which include several layers of regular grids.

Lenticular stereoscopic imaging and displaying techniques with no special glasses

Autostereoscopic 3-D imaging and display system is implemented on the notebook 486 DxII PC with TFT active matrix LCD display module and accompanying lenticular sheet lens. An image processing board (e.g. Targa Plus which is commercially available) is used to capture and display the image. Display experiments for still images and animating graphics images were very promising and satisfactory. Measured depth perception is about 100 mm on a notebook PC LCD display unit. The compact design of lens-plate and TFT LCD display module would be appropriate for 3-D game machines, stereoscopic TV system on multimedia PC.

Multichannel acousto-optic Bragg cell for real-time electroholography.

A multichannel acousto-optic Bragg cell was made by the joining of acousto-optic cells that have the shape of symmetrical trapezoidal prisms. This acousto-optic Bragg cell has an aperture length equal to the sum of its component acousto-optic cells but has an aperture time equal to that of each acousto-optic cell. We tested the performance of the multichannel acousto-optic Bragg cell by joining six TeO(2) acousto-optic cells together with 300-microm gaps between one another. The holographic fringe data prepared by computer were divided into six equal segments. Each data segment was again divided into six equal parts and then fed into the corresponding acousto-optic cell. The holographic images were reconstructed by the periodical illumination of a green (lambda = 0.5145 microm) pulse laser beam onto the multichannel acousto-optic Bragg cell. The reconstructed images are sharp and clear. This indicates that the multichannel acousto-optic Bragg cell is working properly.

Image Registration and Fusion between Passive Millimeter Wave Images and Visual Images

Passive millimeter wave imaging has the capability of detecting concealed objects under clothing. Also, passive millimeter imaging can obtain interpretable images under low visibility conditions like rain, fog, smoke, and dust. However, the image quality is often degraded due to low spatial resolution, low signal level, and low temperature resolution. This paper addresses image registration and fusion between passive millimeter images and visual images. The goal of this study is to combine and visualize two different types of information together: human subjects identity and concealed objects. The image registration process is composed of body boundary detection and an affine transform maximizing cross-correlation coefficients of two edge images. The image fusion process comprises three stages: discrete wavelet transform for image decomposition, a fusion rule for merging the coefficients, and the inverse transform for image synthesis. In the experiments, various types of metallic and non-metallic objects such as a knife, gel or liquid type beauty aids and a phone are detected by passive millimeter wave imaging. The registration and fusion process can visualize the meaningful information from two different types of sensors.

Three-Dimensional Object Reconstruction and Recognition Using Computational Integral Imaging and Statistical Pattern Analysis

In this paper, we discuss computational reconstruction and statistical pattern classification using integral imaging. Three-dimensional object information is numerically reconstructed at arbitrary depth-levels by averaging the corresponding pixels. The longitudinal distance and object boundary are estimated where the standard deviation of the intensity is minimized. Fisher linear discriminant analysis combined with principal component analysis is adopted for the classification of out-of-plane rotated objects. The Fisher linear discriminant analysis maximizes the class-discrimination while the principal component analysis minimizes the error between the original and the restored images. The presented method provides promising results for the distortion-tolerant pattern classification.

Live 3-D video in volumetric display

A live volumetric image is created from a plane image taken by a CCD camera with the aid of depth-wise segmented images from a high-speed B/W camera. The segmented images are obtained by a rotating screen in the image volume of an objective with a large aperture objective. By processing the output signal from the B/W camera, the boundary of each segmented image from the camera is extracted. This boundary information is used to control the frame size of CCD camera image, which is projected through CRT projector to another rotating screen to generate volumetric image. The rotating screen displays image with frame speed of 30Hz. Each volumetric image is consisted of 8 layers. The rotating screen has a form of rotating cylinder with 8 slanted leaves along its circumference with an equal distance.