Byeongho Choi

Efficient RGB Video Coding Using Adaptive Inter-Plane Residual Prediction

This paper presents an efficient video coding algorithm in the RGB color space. Currently most video coding algorithms are based on a decorrelated color space such as YCbCr which has reduced inter-color redundancy. For high fidelity video applications, however, it is essential to maintain the original signal fidelity. In pursuit of both high fidelity and coding efficiency, we propose an adaptive inter-plane residual prediction algorithm exploiting inter-color redundancy of the RGB signal. Simulation results show that the proposed algorithm can increase RGB video coding efficiency up to 0.9 dB, compared to the existing H.264/AVC High 4:4:4 Intra profile.

An ontology for integrating multimedia databases

This paper proposes a multimedia ontology that will support semantic integration of multimedia databases. The ontology is defined by integrating MPEG-7 MDS and TV-AnyTime metadata. A procedure to integrate these two standards is described and relationship of their elements is also presented. We also designed and implemented a framework for integrating multimedia databases and showed that any multimedia metadata can be mapped to the proposed ontology.

Optimization of H.264 encoder using adaptive mode decision and SIMD instructions

This work presents algorithms that optimize the baseline H.264 encoder without loss of image quality and compression ratio. We propose an adaptive mode decision algorithm to speedup complex mode decision with rate distortion optimization (RDO). Also we optimize computation-intensive modules using single instruction multiple data (SIMD) instructions. As a result, the proposed encoder is ten times faster than the JM72 reference encoder.

Scalable multiple GPU architecture for super multi-view synthesis using MVD

This paper presents a scalable multiple GPU architecture for super multi-view (SMV) synthesis using the multi-view video plus depth (MVD) data. SMV synthesis is essential to generate 3D contents for the SMV 3D display with hundred views. SMV 3D display, recently released to support 108 viewpoints, shows the multiplexed result of small viewing interval. Hence, we should synthesize the intermediate views over a hundred for each pair of two cameras in multi-camera system. View synthesis of more than hundred high resolution images, however, needs massive data processing, which is linearly increased in proportion to the number of synthesized views. In this paper, we propose a real-time SMV synthesis method using multiple GPU. The scalability of GPU can be utilized to reduce the processing time of view synthesis without any changes of the kernel function. We evaluate the proposed method for synthesizing 180 intermediate views from 18 input HD images according to the number of GPUs. We show that 180 intermediate views can be synthesized in real-time using 4 GPUs.

Fusion of Local and Global Detectors for PHD Filter-Based Multi-Object Tracking

In this paper, a novel multi-object tracking method to track an unknown number of objects is proposed. To handle multiple object states and uncertain observations efficiently, a probability hypothesis density (PHD) filter is adopted and modified. The PHD filter is capable of reducing false positives, managing object appearances and disappearances, and estimating the multiple object trajectories in a unified framework. Although the PHD filter is robust in cluttered environments, it is vulnerable to false negatives. For this reason, we propose to exploit local observations in an RFS of the observation model. Each local observation is generated by using an online trained object detector. The main purpose of the local observation is to deal with false negatives in the PHD filtering procedure. The experimental results demonstrated that the proposed method robustly tracked multiple objects under practical situations.

Automatic keystone correction using a single camera

In this paper, we introduce an algorithm for removing keystone distortion, which frequently occurs when the projector is not precisely aligned to the screen, For this purpose, we generate a pre-warp image from the transformation between the projector and the screen using a single camera while automatically computing homography from the pattern and screen images and determining a scaled rigid body transform. Thus our method is useful for multi-projector-based applications.

Background subtraction using edge cues and color difference for stabilized CMOS images

Video stabilization followed by background subtraction using CMOS sensor shows erroneous foregrounds. In this paper, we present a background subtraction method using edge cues and color difference to deal with preprocessed stabilized images. We use a non-parametric background model with edge cues based on the observation that interpolation errors are larger in textured regions than in homogeneous regions. By additional CIELab difference model, we show that misclassifications are dramatically decreased than conventional background subtraction methods.

Method of Measuring Color Difference Between Images using Corresponding Points and Histograms

Color correction between two or multiple images is very crucial for the development of subsequent algorithms and stereoscopic 3D camera system. Even though various color correction methods are proposed recently, there are few methods for measuring the performance of these methods. In addition, when two images have view variation by camera positions, previous methods for the performance measurement may not be appropriate. In this paper, we propose a method of measuring color difference between corresponding images for color correction. This method finds matching points that have the same colors between two scenes to consider the view variation by correspondence searches. Then, we calculate statistics from neighbor regions of these matching points to measure color difference. From this approach, we can consider misalignment of corresponding points contrary to conventional geometric transformation by a single homography. To handle the case that matching points cannot cover the whole regions, we calculate statistics of color difference from the whole image regions. Finally, the color difference is computed by the weighted summation between correspondence based and the whole region based approaches. This weight is determined by calculating the ratio of occupying regions by correspondence based color comparison.

Lossless image coding based on inter-color prediction for ultra high definition image

This paper addresses the lossless image coding for ultra-high definition television system which supports 4K (4096×2160) resolution image with 22.2ch audio. Ultra High Definition Tele-vision system is being developed to satisfy end-user who has a longing for higher resolution, higher quality, and higher fidelity picture and sound. However, the major characteristic of Ultra High Definition Tele-vision system is considerably huge input information must be processed in real-time compare to conventional systems. Therefore high speed data handling for editing and playing, high speed signal interface between devices and real-time source codecs without delay for saving memory space are unavoidable requirements of ultra-high system. This paper focused on lossless image codec for the reason of real-time processing with reasonable coding gain and the proposed algorithms is pixel based algorithms called spatio-color prediction. The proposed algorithm uses inter-color correlation with spatial correlation appropriately and it shows 5.5% coding efficiency improvement compare to JPEG-LS. The simulation was performed using 4K resolution RGB 10bit images and it is claimed that the proposed lossless coding was verified under the developed Ultra High Definition Tele-vision system.