EXPERIMENTAL ASSESSMENT OF TECHNIQUES FOR FISHEYE CAMERA CALIBRATION

José Marcato Junior,Antonio Maria Garcia Tommaselli,Marcus Vinícius Antunes De Moraes

doi:10.1590/s1982-21702015000300036

José Marcato Junior, Antonio Maria Garcia Tommaselli + Show 1 more

Open Access

https://doi.org/10.1590/s1982-21702015000300036

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Abstract

Abstract:Fisheye lens cameras enable to increase the Field of View (FOV), and consequently they have been largely used in several applications like robotics. The use of this type of cameras in close-range Photogrammetry for high accuracy applications, requires rigorous calibration. The main aim of this work is to present the calibration results of a Fuji Finepix S3PRO camera with Samyang 8mm fisheye lens using rigorous mathematical models. Mathematical models based on Perspective, Stereo-graphic, Equi-distant, Orthogonal and Equi-solid-angle projections were implemented and used in the experiments. The fisheye lenses are generally designed following one of the last four models, and Bower-Samyang 8mm lens is based on Stereo-graphic projection. These models were used in combination with symmetric radial, decentering and affinity distortion models. Experiments were performed to verify which set of IOPs (Interior Orientation Parameters) presented better results to describe the camera inner geometry. Collinearity mathematical model, which is based on perspective projection, presented the less accurate results, which was expected because fisheye lenses are not designed following the perspective projection. Stereo-graphic, Equi-distant, Orthogonal and Equi-solid-angle projections presented similar results even considering that Bower-Samyang fisheye lens was built based on Stereo-graphic projection. The experimental results also demonstrated a small correlation between IOPs and EOPs (Exterior Orientation Parameters) for Bower-Samyang lens.

Highlights

Omnidirectional Vision systems that enable 360° imaging have been widely used in several research fields such as robot navigation, telepresence, close-range Photogrammetry and virtual reality (Kang and Szeliski, 1997; Yagi, 1999; Spacek, 2005; Sturm et al, 2010)
The main aim of this paper is to present the results achieved in the calibration of a Fuji-Finepix S3pro digital camera with Bower-Samyang 8mm fisheye lens using rigorous mathematical models
The aim of this paper was to assess the results of calibration trials performed with a Fuji-Finepix S3pro camera with Bower-Samyang 8mm lens, using rigorous mathematical models

Summary

Introduction

Omnidirectional Vision systems that enable 360° imaging have been widely used in several research fields such as robot navigation, telepresence, close-range Photogrammetry and virtual reality (Kang and Szeliski, 1997; Yagi, 1999; Spacek, 2005; Sturm et al, 2010). Omnidirectional images can be acquired using: camera with fisheye lenses; moving cameras or optical elements; catadioptric systems (camera and mirror); and multiple cameras with divergent views (Sturm et al 2010). (Van Den Heuvel et al, 2006) presented a system developed by Cyclomedia composed of two fisheye lens camera with a FOV (Field of View) of approximately 185°, generating omnidirectional images called Cycloramas. In Photogrammetry, the Collinearity mathematical model, based on perspective projection combined with lens distortion models, is generally used in the camera calibration process. Fisheye lenses are designed following different projections models such as: Stereo-graphic, Equi-distant, Orthogonal and Equi-solid-angle. The fisheye lenses follow the Equi-distant and Equi-solid-angle projections (Abraham and Förstner, 2005; Schneider et al, 2009)

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