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- Title
Use of Gradient-Based Shadow Detection for Estimating Environmental Illumination Distribution.
- Authors
Lee, Sangyoon; Hong, Hyunki
- Abstract
Environmental illumination information is necessary to achieve a consistent integration of virtual objects in a given image. In this paper, we present a gradient-based shadow detection method for estimating the environmental illumination distribution of a given scene, in which a three-dimensional (3-D) augmented reality (AR) marker, a cubic reference object of a known size, is employed. The geometric elements (the corners and sides) of the AR marker constitute the candidate's shadow boundary; they are obtained on a flat surface according to the relationship between the camera and the candidate's light sources. We can then extract the shadow regions by collecting the local features that support the candidate's shadow boundary in the image. To further verify the shadows passed by the local features-based matching, we examine whether significant brightness changes occurred in the intersection region between the shadows. Our proposed method can reduce the unwanted effects caused by the threshold values during edge-based shadow detection, as well as those caused by the sampling position during point-based illumination estimation.
- Subjects
SHADES &; shadows; LIGHTING; OBJECT recognition (Computer vision)
- Publication
Applied Sciences (2076-3417), 2018, Vol 8, Issue 11, p2255
- ISSN
2076-3417
- Publication type
Article
- DOI
10.3390/app8112255