Ho-Hyun Kang

Recognition of 3D objects by use of computational integral imaging reconstruction

In this paper, a novel resolution-enhanced three-dimensional (3-D) image correlator by use of computationally reconstructed integral images is proposed to extract accurate location data of 3-D objects. Elemental images of the target and reference objects are picked up by lenslet arrays and from which, high-resolution target and reference plane images are reconstructed at the output plane by using a computational integral imaging reconstruction technique. Then, through cross-correlations between the reconstructed reference and target plane images, 3-D location data of the target objects in a scene can be robustly extracted. To show the feasibility of the proposed method, some experiments are carried out and its results are presented as well.

Compression enhancement using the hybrid motion estimation in sub-image array transformed from elemental image array in three-dimensional integral image

In this paper, we suggest the enhanced compression scheme using the hybrid motion-estimation in sub-image array (SIA) transformed from elemental image array (EIA) in three-dimensional integral imaging. In the proposed method, firstly, a macroblock in the reference sub-image (SI) is matched in the local SI applying to MSE (Motion Square Estimation) by three step search (TSS) to search the coordinates of current macro block. The second step is to search the most matched area in SIs and the coordinate of macro block for full searching, and finally, the start point for searching in the local SI is altered by the former coordinate. Accordingly, the computed motion estimation from the block-matching with TSS and the full searching is presented as MV and the object in the reference SI is shifted to the object position of each current SIs to compensate their MV based on the motion estimation. The computation time for block-matching by the TSS to search approximate current macro block range in the first step and the full searching to acquire the exact current macro block range in the second step is decreased. In addition, the video compression such as MPEG-4 is applied to encode the data of the consecutive frames. Some experiments are carried out and compression efficiency of the proposed scheme has been improved 676.30%, 357.19% and 3.37% on the condition of 30[dB] approximately, compared with the JPEG compression, EIA compression and Full searching method. The computation time is also improved 196.97% compared with the full search scheme for motion estimation and compensation.

Implementation of multiview calibration system for an effective 3D display

In this paper, we proposed multiview calibration system for an effective 3D display. This system can obtain 4-view image from multiview camera system. Also it can be rectify lens and camera distortion, an error of bright and color, and it can be calibrate distortion of geometry. We proposed the signal processing skill to calibrate the camera distortions which are able to take place from the acquired multiview images. The discordance of the brightness and the colors are calibrated the color transform by extracting the feature point, correspondence point. In addition, the difference of brightness is calibrated by using the differential map of brightness from each camera image. A spherical lens distortion is corrected by extracting the pattern of the multiview camera images. Finally the camera error and size among the multiview cameras is calibrated by removing the distortion. Accordingly, this proposed rectification & calibration system enable to effective 3D display and acquire natural multiview 3D image.

Compression scheme by use of object-segmented sub-image array transformed from computational elemental image array based on multiple objects in 3D integral imaging

In this paper, we address a highly enhanced compression scheme in the condition of multiple objects in Integral Imaging (InIm) by use of sub-images (SIs) to segment each object and to remove the Motion Vector (MV) of residual image array transformed from Sub-Image Array (SIA). In the pick-up process, SIA is generated from EIA after the perspectives passing through virtual pinhole array is recorded as Elemental Image Array (EIA). The similarity enhancement among SIs expects compression efficiency to improve, but the compression efficiency of the EIA in the picked-up condition of multiple objects does not correspond to that of the picked-up condition of a simplified object. In the proposed scheme, the depth of objects is computed by two adaptive SIs located at horizontal left and right side from the reference SI positioned to the center of the SIA. A depth map image generated from two adaptive the SIs and a reference SI is applied to segment each object considering to the distance between those. Therefore, an adaptive objectsegmented SI is obtained and, which is motion-estimated from the original SIA based on MSE to generate the motioncompensated object-segmented SIA and which SIAs from each segmented object are finally combined as the motioncompensated SIA, and which based on multiple objects is transformed to residual SIA to minimize the spatial redundancy and which SIA is compressed by MPEG-4. The proposed algorithm shows the enhanced compression efficiency than that of the baseline JPEG and the conventional EIA compression scheme.

Efficient compression scheme by use of the region division of elemental images on MALT in three-dimensional integral imaging

This paper addresses the efficient compression scheme of elemental image array (EIA) generated from the moving array lenslet technique (MALT) based on MPEG-4. The EIAs are picked-up by MALT controlling the spatial ray sampling of ray and which produces few EIAs that the positions of the lenslet arrays are rapidly vibrated in the lateral directions within the retention time of the afterimage of human eye. To enhance the similarity in each EIA picked-up by MALT, several EIAs obtained from MALT are regenerated by the collection of an elemental image occupied at the same position in each EIA. The newly generated each EIA has high similarity among adjacent elemental images. To illustrate the feasibility of the proposed scheme, some experiments are carried out to show the increased compression efficiency and we obtained the improved compression ratio of 12% compared to the unhandled compression scheme.

Compression scheme of sub-image transformed elemental images based on residual images in 3D computational integral imaging systems

In this paper, we proposed a highly enhanced compression scheme of the integral imaging (InIm) applying to the residual image (RI) array transformed from Sub-Image Array (SIA). In the pickup process, the object through the virtual pinhole array is recorded in a computer as Elemental Image Array (EIA). Then, SIA is generated from EIA. It provides enhanced compression efficiency by improving the similarity between sub-images (SIs). In the proposed scheme, the reference image is the first one of rearranged SIs based on spiral scanning topology and the RIs are generated from difference between reference image and SIs. Finally, we model the reference image and RIs in InIm as consecutive frames in a moving picture. Therefore, the video compression scheme such as MPEG-4 can be applied to data reduction of the consecutive frames. Experimental results are presented to illustrate the image quality of MPEG-4 and JPEG with the same compression rate. Some experiment is carried out and compression efficiency of the proposed scheme has been improved 296.02% in average according to the each quality factor.