ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., IV-1/W1, 237-245, 2017
https://doi.org/10.5194/isprs-annals-IV-1-W1-237-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
 
30 May 2017
GEOMETRIC CALIBRATION OF FULL SPHERICAL PANORAMIC RICOH-THETA CAMERA
S. Aghayari1, M. Saadatseresht1, M. Omidalizarandi2, and I. Neumann2 1Faculty of Surveying and Geospatial Engineering, College of Engineering, University of Tehran, Iran
2Geodetic Institute, Leibniz Universität Hannover, Germany
Keywords: Fisheye Lens, Full Spherical Panorama, Omnidirectional Camera, Network Calibration Abstract. A novel calibration process of RICOH-THETA, full-view fisheye camera, is proposed which has numerous applications as a low cost sensor in different disciplines such as photogrammetry, robotic and machine vision and so on. Ricoh Company developed this camera in 2014 that consists of two lenses and is able to capture the whole surrounding environment in one shot. In this research, each lens is calibrated separately and interior/relative orientation parameters (IOPs and ROPs) of the camera are determined on the basis of designed calibration network on the central and side images captured by the aforementioned lenses. Accordingly, designed calibration network is considered as a free distortion grid and applied to the measured control points in the image space as correction terms by means of bilinear interpolation. By performing corresponding corrections, image coordinates are transformed to the unit sphere as an intermediate space between object space and image space in the form of spherical coordinates. Afterwards, IOPs and EOPs of each lens are determined separately through statistical bundle adjustment procedure based on collinearity condition equations. Subsequently, ROPs of two lenses is computed from both EOPs. Our experiments show that by applying 3*3 free distortion grid, image measurements residuals diminish from 1.5 to 0.25 degrees on aforementioned unit sphere.
Conference paper (PDF, 1025 KB)


Citation: Aghayari, S., Saadatseresht, M., Omidalizarandi, M., and Neumann, I.: GEOMETRIC CALIBRATION OF FULL SPHERICAL PANORAMIC RICOH-THETA CAMERA, ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., IV-1/W1, 237-245, https://doi.org/10.5194/isprs-annals-IV-1-W1-237-2017, 2017.

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