A mobile approach to modeling urban areas using laser range scanners and color imagery

Joonki Paik,Mongi A. Abidi 중앙대학교 문화콘텐츠기술연구원 2002 다문화콘텐츠연구 Vol.1 No.-

Analysis of Space Roundness with Converged Stereo Camera for Realistic 3D Content Production

Myungha Kim,Joonki Paik,Hyunki Hong 중앙대학교 영상콘텐츠융합연구소 2015 TechArt :Journal of Arts and Imaging Science Vol.2 No.1

It is necessary to match the viewpoint of the camera with user’s viewpoint during stereoscopic image production. In this matching process, distortion occurs as a result of optical errors. Accordingly, sweetening process is needed to reinterpret the geometric element of an image and minimize eyestrain. Particularly, the phenomenon of space roundness which occurs in converged image contents by the convergence method, causes eye-strain according to the viewing position. In addition, the paradoxical effects meaning the difference in spatial information caused by the combination of different depth information during CG/real 3D image synthesis can occur. This paper presents an effective method for 3D synthesis by understanding the cause of roundness in the process of synthesizing real stereo images with the convergence method and the CG object. The proposed method is applicabale for high-quality 3D stereoscopic images production by predicting and interpreting inconsistency in spatial structure relation between CG and real images.

Three-dimensional simulation method of fish-eye lens distortion for a vehicle backup rear-view camera.

Kim, Daehee,Paik, Joonki The Society 2015 Journal of the Optical Society of America. A, Opti Vol.32 No.7

<P>Recently, various cameras have been embedded in vehicles for driver safety and convenience. In this context, a backup rear-view camera has attracted increasing attention in helping drivers' parking convenience. Preinstallation of a rear-view camera requires the calibration of a wide-angle lens, such as a fish-eye lens, and the registration of guidelines to the three-dimensional (3D) scene. The proposed method provides a novel simulation method for the optical distortion of a wide-angle lens in a vehicle rear-view camera. The proposed method consists of three steps: (i) generation of the 3D virtual space, (ii) field number-based viewing angle estimation, and (iii) distorted image generation in the 3D space. The major contribution of this work is the lens specification-based simulation of 3D distortion for accurate and efficient preinstallation of vehicle rear-view cameras. The proposed simulation method can also be used to design a general optical imaging system for intelligent surveillance and medical imaging.</P>

Uniform depth regionbased registration between colour channels and its application to single camerabased multifocusing

Jinhee Lee,Joonki Paik IET 2013 IET image processing Vol.7 No.1

<P>This study presents a spatially varying image registration method based on regions of the same depth. The proposed registration method uses phase correlation matching to measure colour shifting vectors (CSVs) between colour channels in a pre-specified region of the same distance to the camera, and aligns colour channels of the corresponding region according to the CSV. The authors also present the foreground region detection method by using binary edge labelling and analysis of histograms of channel-shifting features. The major contribution of this study is 2-fold: (i) the proposed method can be considered as a region-wise approximated version of fully non-rigid registration, which is widely used in the medical imaging area, and (ii) it can compensate misalignment between red (R), green (G) and blue (B) colour channels caused by refraction and chromatic aberration of a multiple colour-filtered aperture (MCA) camera, which has been proposed as a single camera-based multifocusing system. Among various applications of non-rigid image registration, the proposed region-based registration method is particularly suitable for multifocusing images acquired by an MCA camera. In depth analysis of each step of the proposed algorithm is provided with experimental results, and its application to the MCA camera is also provided to realise efficient depth estimation and highly accurate multifocusing functions using a single camera. Without using joint histogram or geometric transformation, the proposed region-adaptive approach successfully approximates the fully non-rigid registration with significantly reduced amount of computation.</P>

Spatially Adaptive Histogram Equalization for Single Image-Based Ghost-free High Dynamic Range Imaging

Jaehyun Im,Joonki Paik 중앙대학교 영상콘텐츠융합연구소 2014 TechArt :Journal of Arts and Imaging Science Vol.1 No.1

In this paper, we present a spatially adaptive histogram equalization method for generating a ghost-free high dynamic range (HDR) image using a single input image. Existing multiple input-based HDR methods fuse multiple low dynamic range (LDR) images, acquired using different exposures. However, these methods work only under the assumption that neither global nor local motions exists in between the LDR images. To overcome such an unrealistic constraint, we generate two LDR images from a single input image. To generate LDR images with appropriate exposures, we divide the entire intensity range into multiple sub-ranges using histogram quantization and separately perform histogram equalization in each sub-range. Thus, we can acquire a set of differently exposed LDR images of the same scene, which are then fused to generate a ghost-free HDR image. The major contribution of this work is twofold: (i) a novel estimation method for providing optimal sub-ranges of intensity using histogram quantization, which (ii) requires no additional hardware for generating multiple LDR images. Because the proposed method uses a set of optimally self-generated LDR images, it is inherently free of ghost artifacts and can provide a ghost-free HDR function for low-cost, lightweight imaging devices, such as mobile phones and compact cameras.

Sensory-Coevolution in New Media Art

Wonjin Song,Joonki Paik 중앙대학교 영상콘텐츠융합연구소 2015 TechArt :Journal of Arts and Imaging Science Vol.2 No.2

The present study aims to analyze the characteristics of the aesthetic experience of new media art from the viewpoint of autopoiesis. The autopoietic viewpoint originated in biology, and is crucial to approaching the relational paradigm beyond dichotomous thinking such as body and soul, human and technology, and subject and object. Through new media artworks, this paper analyzes the interactions that occur when humans encounter autopoiestic characteristics of technology. Identifying the close and sensitive relationships expressed in new media artworks based on such analysis allows us to understand the co-evolutionary relationship between humans and technology. Therefore, the aesthetic experience of new media art is interpreted as a process of coevolution, forming new senses between humans and technology; it is expected to make various attempts to free the relationship of humans with technology and environment in the field of new media art.

Low-Rank Representation-Based Object Tracking Using Multitask Feature Learning with Joint Sparsity

Kim, Hyuncheol,Paik, Joonki Hindawi Limited 2014 Abstract and applied analysis Vol.2014 No.-

<P>We address object tracking problem as a multitask feature learning process based on low-rank representation of features with joint sparsity. We first select features with low-rank representation within a number of initial frames to obtain subspace basis. Next, the features represented by the low-rank and sparse property are learned using a modified joint sparsity-based multitask feature learning framework. Both the features and sparse errors are then optimally updated using a novel incremental alternating direction method. The low-rank minimization problem for learning multitask features can be achieved by a few sequences of efficient closed form update process. Since the proposed method attempts to perform the feature learning problem in both multitask and low-rank manner, it can not only reduce the dimension but also improve the tracking performance without drift. Experimental results demonstrate that the proposed method outperforms existing state-of-the-art tracking methods for tracking objects in challenging image sequences.</P>

On a Starry Night: Interactive Media Art Using Eye Gaze Tracking

Youngran Jo,Joonki Paik 중앙대학교 영상콘텐츠융합연구소 2017 TechArt :Journal of Arts and Imaging Science Vol.4 No.4

Object tracking using compressive local appearance model with ℓ₁-regularisation

Hyuncheol Kim,Joonki Paik IET 2014 Electronics letters Vol.50 No.6

<P>A novel compressive local appearance model-based object tracking algorithm is presented to address challenging issues in object tracking. To efficiently preserve image patches of an object and reduce the dimensionality, a random projection-based feature selection method is introduced. Modelling the object's appearance using a sparse representation over a set of templates leads to an ℓ<SUB>1</SUB>-regularisation problem. To solve this problem, both the reconstruction error and the residual matrix are considered which play a key role in tracking an object with severe appearance variations using the modified likelihood function. Experimental results demonstrate that the proposed method outperforms existing state-of-the-art tracking methods in terms of dealing with long-term partial occlusion, deformation and rotation.</P>

Sound Visualization Using Color Transformation and 3D Effect

Byeongho Moon,Joonki Paik 중앙대학교 영상콘텐츠융합연구소 2017 TechArt :Journal of Arts and Imaging Science Vol.4 No.1