Sang-Tae Lee

Efficient generation of CGH of 3-D objects by use of run-length encoding and look-up table methods

In this paper, we propose a new approach for fast generation of computer-generated holograms (CGHs) of a 3-D object by using the run-length encoding (RLE) and the novel look-up table (N-LUT) methods. With the RLE method spatially redundant data of a 3-D object are extracted and re-grouped into the N-point redundancy map according to the number of the adjacent object points having the same 3-D value. Then, basing on this redundancy map N-point principle fringe patterns (PFPs) are newly calculated by using the 1-point PFP of the N-LUT (novel look-up table) and the CGH pattern for the 3-D object is generated with these N-point PFPs. In this approach, object points to be involved in calculation of the CGH pattern can be dramatically reduced and as a result an increase of computational speed can be obtained. Some experiments with a test 3-D object are carried out and the results are compared to those of the conventional methods.

Optical implementation of improved resolution with intermediate-view reconstruction technique based on integral imaging

To overcome the viewing resolution limit defined by the Nyquist sampling theorem for a given lenslet pitch, a Moving Array-Lens Technique (MALT) was developed in 3-D integral imaging technique. Even though the MALT is an effective method for resolution improvement of Integral Imaging, this cannot be applied to a real-time 3-D integral imaging display system because of its mechanical movement. In this paper, we propose an integral imaging display using a computational pick-up method based on Intermediate-View Reconstruction Technique instead of optical moving pickup. We show that the proposed system can provide optically resolution-improved 3-D images of integral imaging by use of EIs generated by the IVRT through the optical experiments.

Effective reconstruction of stereoscopic image pair by using regularized adaptive window matching algorithm

Abstract In this paper, an effective method for reconstruction of stereoscopic image pair through the regularized adaptive disparity estimation is proposed. Although the conventional adaptive disparity window matching can sharply improve the PSNR of a reconstructed stereo image, but there still exist some problems of overlapping between the matching windows and disallocation of the matching windows, because the size of the matching window tend to changes adaptively in accordance with the magnitude of the feature values. In the proposed method, the problems relating to the conventional adaptive disparity estimation scheme can be solved and the predicted stereo image can be more effectively reconstructed by regularizing the extimated disparity vector with the neighboring disparity vectors. From the experimental results, it is found that the proposed algorithm show improvements the PSNR of the reconstructed right image by about 2.36 ∼ 2.76 dB, on average, compared with that of conventional algorithms.

Server and client simulator for web‐based 3d image communication

Abstract In this paper, a server and client simulator for the web‐based multi‐view 3D image communication system is implemented by using the IEEE 1394 digital cameras, Intel Xeon server computer and Microsofts DirectShow programming library. In the proposed system, two‐view image is initially captured by using the IEEE 1394 stereo camera and then, this data is compressed through extraction of its disparity information in the Intel Xeon server computer and transmitted to the client system, in which multi‐view images are generated through the intermediate views reconstruction method and finally display on the 3D display monitor. Through some experiments it is found that the proposed system can display 8‐view image having a grey level of 8 bits with a frame rate of 15 fps.

Web-based real-time multiview 3D display system

In this paper, a new web-based multi-view 3D display system through the intermediate views synthesis using an adaptive disparity estimation algorithm is proposed and its performance is analyzed by comparison to those of the conventional disparity estimation algorithms. First, the feature value indicating the local image complexity is extracted from the input stereo sequences by using the edge detection and disparity estimation. Then, the matching window size for disparity estimation is adaptively selected depending on the magnitude of this feature value. This new approach is not only able to reduce the disparity vector mismatch encountered in the conventional dense disparity estimation with small matching window size, but is also able to reduce the blocking effect associated with the disparity estimation using a large matching window size. With some experimental results on a sequence of stereo image captured by the web-cameras, it is found that the adaptive algorithm improves PSNRs on the average in comparison with those of the conventional algorithms and multi-view images can be generated through the process of real-time IVS. Finally it is suggested that this approach can be applied to the web-based real-time 3D video communication system.