1. 연구목적

웨어러블 장비와 모바일 디바이스의 성능이 크게 개선되면서, 이를 활용하는 증강현실(augmented reality)과 가상현실(virtual reality) 관련 기술에 대한 관심이 높아지고 있다. 최근에는 사용자의 움직임에 따른 시점변화를 실시간에 해석해 HMD(Head Mounted Device), 스마트 폰 등의 장비에 영상정보를 제공하는 수준을 뛰어 넘는 기술이 개발되고 있다. 본 연구에서는 주변 환경(상황) 변화 등을 고려하는 환경연계형 AR 기술과 모바일 기반 어플리케이션을 개발한다. 즉, 사용자가 위치한 환경에서 주변 조명을 해석하고, 이를 반영하여 보다 사실적인 합성영상을 생성할 수 있다. 

2. 연구내용

(1) 연구요약

Mobile devices are becoming powerful enough to realize augmented reality (AR) application. This paper introduces two AR methods to estimate an environmental illumination distribution of a scene. In the first method, we extract the lighting direction and intensity from input images captured with a front-side camera of a mobile device, using its orientation sensor. The second method extracts shadow regions cast by three dimensional (3D) AR marker of known shape and size. Because previous methods examine per pixel shadow intensity, their performances are much affected by the number of sampling points, positions, and threshold values. By using a simple binary operation between the previously clustered shadow regions and the threshold real shadow regions, we can compute efficiently their relative area proportions according to threshold values. This area-based method can overcome point sampling problem and threshold value selection. Experiment results demonstrate that the proposed methods generate natural image with multiple smooth shadows in real-time. 

(2) 연구결과

C. Eem, I. Kim, Y. Jung, and H. Hong, "Estimating illumination distribution to generate realistic shadows in augmented reality," KSII Trans. on Internet and Information Systems, vol. 9, no. 6, 2015 (SCIE). 

C. Eem, I. Kim, and H. Hong, "Using gradient-based ray and candidate shadow maps for environmental illumination distribution estimation," Optical Engineering, vol.54, no.7, 2015 (SCI).

S. Han, J. Shin, K. Kim, S. Lee, and H. Hong. “Using human objects for illumination estimation and shadow generation in outdoor environments,” Symmetry, vol.11, no.10, 2019 (SCIE).