Seung Chull Park

Pylephlebitis associated with appendicitis.

Pylephlebitis usually occurs secondary to infection in the region drained by the portal venous system. A most common antesecent focus of infection is diverticulitis and the most common blood isolate is E. coli (54%), followed by Proteus mirabilis (23%). Overall mortality is 32% and most of the patients who had died had severe sepsis prior to the initiation of antibiotic therapy. We describe a case of pylephlebitis which had appendicitis and consequent septic thrombosis of the portal vein and its branches, with dissemination of infection to the liver. The patient had recovered due to timely antibiotic treatment alone and resulted in complete resolution. Early diagnosis and treatment are basic to a favorable clinical course.

Improved pupil center localization method for eye-gaze tracking-based human-device interaction

This paper presents an improved pupil center (PC) localization method for eye-gaze tracking. In the proposed method, an input infrared eye image is repeatedly binarized with a finite number of different thresholds to produce a stack of binary images. Among all the blobs, which are groups of connected binary pixels in the binary image stack, we find a blob whose shape is the most similar to pupil, in terms of the size, the aspect ratio, the moments, and the circularity. Consequently, the centroid of the final resultant blob is regarded as the PC location. Experimental results show that the proposed method outperforms conventional ones.

A novel iris center localization method based on the spherical eyeball rotation model for human-device interaction

This paper presents a novel iris center (IC) localization algorithm for human-device interaction (HDI). In the proposed method, many different IC locations and their corresponding iris boundaries (IBs) are first registered as a database. Using the database, IB matching is performed to locate the IC. Experimental results show that the proposed algorithm outperforms the conventional ones especially when the iris is located at the corners of the eye.

Camera-based color calibration method for multiple flat-panel display system

Multiple flat-panel displays may often seem different in color, even though they are of the same brand and model. As a result, users experience visual fatigue as well as degraded quality while watching displayed contents. In this paper, we propose a method of calibrating multiple displays simultaneously with the use of ordinary cameras, such as a smartphone camera. In the proposed method, brightness synchronization and white point matching are performed for multiple display calibration. Experimental results show that the proposed method achieves a truly unnoticeable color difference between the adjacent displays in terms of ΔE*94, the standard color distance metric.

Camera-Based Color Calibration Method for Multiple Flat-Panel Displays Using Smartphone

Multiple flat-panel displays have been widely used as business and consumer electronic equipment. Although stereo or multiple display units are of the same brand and model, users often experience temporary visual fatigue due to the color differences between flat-panel displays. Therefore, color calibration between multiple display units displayed at the same time has been receiving attention from display manufacturers. In this paper, a camera-based color calibration method for multiple flat-panel displays that uses a portable smartphone camera is proposed. The color calibration algorithm used in the proposed method consists of three parts: geometric registration based on a chessboard detector, camera parameter optimization based on the distortion model of cameras optical system and environmental factors, and color matching for fast calibration. Experimental tests proved the practicality and the reliable calibration performance of the proposed color calibration method for the aftermarket