Calibration of high resolution digital camera using self-calibration bundle adjustment method

摘要

Currently, the price of digital camera is decreasing and many users afford to purchase it. The digital camera can be used for many applications. The digital camera can also be used for accurate measurement such as determination of three dimensional (3D) coordinates, production of accurate measurement and generation of 3D model of objects. However, the digital camera need to be calibrated to obtain accurate results. The aim of this study is to calibrate the digital camera so that it could be used for accurate measurement. In this study, close range photogrammetric technique was used to calibrate three high resolution digital cameras. The digital cameras used comprise of Rollei D30, Nikon D60 SLR and compact Nikon Coolpix S560. The three digital cameras were used to acquire photographs of three different sizes of testfield that are equipped with retro-reflective targets. The approximate 3D coordinates of the different testfield were estimated by measuring it manually. The three digital cameras were calibrated using self-calibration bundle adjustment method. The photographs of the testfield were acquired using potrait and landscape setup for each camera location in 3D space. After the acquisition of the photographs of the testfield, they were downloaded into the computer for the measurement process of the retro-reflective targets and subsequently the final 3D coordinates of the retro-reflective targets were determined using the self-calibration bundle adjustment method. The coordinates of the retro-reflective targets were also determined using intersection method of total station which were used as referenced value. The 3D coordinates from the digital camera were then compared with the 3D coordinates of the total station. Results showed that the Nikon D60 SLR digital camera is superior than the other two digital cameras in term of accuracy and network precision. The next best result is shown by the Nikon Coolpix S560 compact digital camera and finally the Rollei D30. For the Rollei D30, the results are less accurate than the Nikon D60 SLR. However, the interior orientation parameters of this camera are very stable. In conclusion, all the three high resolution digital cameras have the potential to be used for various close range applications.