Generalized Image Acquisition and Analysis

Maximum Mipmaps for Fast, Accurate, and Scalable Dynamic Height Field Rendering

This paper presents a GPU-based, fast, and accurate dynamic height field rendering technique that scales well to large scale height fields. Current real-time rendering algorithms for dynamic height fields employ approximate ray-height field intersection methods, whereas accurate algorithms require pre-computation in the order of seconds to minutes and are thus not suitable for dynamic height field rendering. We alleviate this problem by using maximum mipmaps, a hierarchical data structure supporting accurate and efficient rendering while simultaneously lowering the pre-computation costs to negligible levels. Furthermore, maximum mipmaps allow for view-dependent level-of-detail rendering. In combination with hierarchical ray-stepping this results in an efficient intersection algorithm for large scale height fields.

Projects

Synchronization and Rolling Shutter Compensation for Consumer Video Camera Arrays

Derek Bradley, Bradley Atcheson, Ivo Ihrke, Wolfgang Heidrich
In: Proceedings of PROCAMS 2009 (2nd best paper).



Abstract

Two major obstacles to the use of consumer camcorders in computer vision applications are the lack of synchronization hardware, and the use of a "rolling" shutter, which introduces a temporal shear in the video volume. We present two simple approaches for solving both the rolling shutter shear and the synchronization problem at the same time. The first approach is based on strobe illumination, while the second employs a subframe warp along optical flow vectors. In our experiments we have used the proposed methods to effectively remove temporal shear, and synchronize up to 16 consumer-grade camcorders in multiple geometric configurations.
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Bibtex

@INPROCEEDINGS{Bradley:2009,
author = {Derek Bradley and Bradley Atcheson and Ivo Ihrke and Wolfgang Heidrich},
title = {Synchronization and Rolling Shutter Compensation for Consumer Video Camera Arrays},
journal = {International Workshop on Projector-Camera Systems (PROCAMS 2009)},
year = {2009},
}
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