Presentation Information
[A-8-16]A Study on Intrinsic Calibration of Digital Camera Based on Star Catalogue
◎Haruya Matsuo1, Ayami Yamakita1, Hideaki Maehara2 (1. Graduate School of Fukuoka Institute of Technology Univ., 2. Fukuoka Institute of Technology Univ.)
Keywords:
Camera Calibration,Astronomical Photograph,Star Catalogue
In photogrammetry, intrinsic calibration is essential for correcting lens distortion. However, for long-distance imaging like astrophotography, focusing on standard test targets is difficult. To address this, this study attempted intrinsic calibration of a digital camera using astrophotography and star catalogs, drawing on previous telescope calibration methods.First, astrophotographs were captured, and true two-dimensional star positions were extracted from a star catalog to generate "star catalog coordinates." Next, the actual centers of the stars in the images were calculated via autocorrelation, designated as "star image coordinates." These two coordinate systems were overlaid, and intrinsic parameters were applied to the star image coordinates to minimize geometric errors using a non-linear least-squares method.The experiments confirmed the feasibility of this calibration, achieving a Root Mean Square Error (RMSE) of less than 5 pixel. However, practical applications require an RMSE of less than 1 pixel. Future work includes improving star center extraction accuracy to reduce the RMSE below 1 pixel, and applying the calculated parameters to enhance image processing techniques like image composition.