The camera calibration module determines the intrinsic parameters of the camera, including the focal length, center of projection, and radial lens distortion. The procedure for performing camera calibration is very simple. The user must first take several pictures of a flat checkerboard image from different views and distances. Suggested camera poses for acquiring the checkerboard images for calibration are shown here. Ten to twenty images are usually sufficient.
The camera calibration module then processes these checkerboard images to solve for the intrinsic parameters as shown here. There is no need to repeat the calibration stage across projects as long as the zoom settings and camera resolution remain the same. Just calibrate the camera once and the computed intrinsic parameters can be re-used many times. If either the zoom settings or camera resolution change for a specific project, the software will automatically prompt the user to recalibrate the camera for the new settings. Each time the camera is calibrated for a specific zoom and resolution setting, the intrinsic parameters are saved in the PhotoSketch plugin.
IMPORTANT: The zoom (focal length) settings and image dimensions must remain constant throughout the whole calibration process. It must also be identical to the settings used during scene capture.
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