Won-Dong Jang

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A fast and optimized dehazing algorithm for hazy images and videos is proposed in this work. Based on the observation that a hazy image exhibits low contrast in general, we restore the hazy image by enhancing its contrast. However, the overcompensation of the degraded contrast may truncate pixel values and cause information loss. Therefore, we formulate a(More)
An unsupervised video object segmentation algorithm, which discovers a primary object in a video sequence automatically, is proposed in this work. We introduce three energies in terms of foreground and background probability distributions: Markov, spatiotemporal, and antagonistic energies. Then, we minimize a hybrid of the three energies to separate a(More)
A graph-based system to simulate the movements and interactions of multiple random walkers (MRW) is proposed in this work. In the MRW system, multiple agents traverse a single graph simultaneously. To achieve desired interactions among those agents, a restart rule can be designed, which determines the restart distribution of each agent according to the(More)
An efficient coding algorithm for depth map images and videos, based on view synthesis distortion estimation, is proposed in this work. We first analyze how a depth error is related to a disparity error and how the disparity vector error affects the energy spectral density of a synthesized color video in the frequency domain. Based on the analysis, we(More)
A real-time video dehazing algorithm, which reduces flickering artifacts and yields high quality output videos, is proposed in this work. Assuming that a scene point yields highly correlated transmission values between adjacent image frames, we develop the temporal coherence cost. Then, we add the temporal coherence cost to the contrast cost and the(More)
A primary object discovery (POD) algorithm for a video sequence is proposed in this work, which is capable of discovering a primary object, as well as identifying noisy frames that do not contain the object. First, we generate object proposals for each frame. Then, we bisect each proposal into foreground and background regions, and extract features from(More)
A novel quality metric for binary edge maps, called the structural edge quality metric (SEQM), is proposed in this work. First, we define the matching cost between an edge pixel in a detected edge map and its candidate matching pixel in the ground-truth edge map. The matching cost includes a structural term, as well as a positional term, to measure the(More)
A semi-supervised video object segmentation algorithm using multiple random walkers (MRW) is proposed in this work. We develop an initial probability estimation scheme that minimizes an objective function to roughly separate the foreground from the background. Then, we simulate MRW by employing the foreground and background agents. During the MRW process,(More)
An online video segmentation algorithm, based on short-term hierarchical segmentation (STHS) and frame-by-frame Markov random field (MRF) optimization, is proposed in this work. We develop the STHS technique, which generates initial segments by sliding a short window of frames. In STHS, we apply spatial agglomerative clustering to each frame, and then adopt(More)