Camera Calibration for Water-Biota Research: The Projected Area of Vegetation

Sensors

Rene Wackrow¹  Edgar Ferreira²  Jim Chandler²  Koji Shiono² 

[1] School of Civil and Building Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK

关键词: photogrammetry;    underwater imaging;    eco-hydraulics;    flow visualization and imaging;    laboratory studies;    plants reconfiguration;    vegetated flows;   

DOI  :  10.3390/s151229798

来源: mdpi

【 摘 要 】

Imaging systems have an indisputable role in revealing vegetation posture under diverse flow conditions, image sequences being generated with off the shelf digital cameras. Such sensors are cheap but introduce a range of distortion effects, a trait only marginally tackled in hydraulic studies focusing on water-vegetation dependencies. This paper aims to bridge this gap by presenting a simple calibration method to remove both camera lens distortion and refractive effects of water. The effectiveness of the method is illustrated using the variable projected area, computed for both simple and complex shaped objects. Results demonstrate the significance of correcting images using a combined lens distortion and refraction model, prior to determining projected areas and further data analysis. Use of this technique is expected to increase data reliability for future work on vegetated channels.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.