Abstract
Curling distance was measured with high precision by use of digital image analysis in order to obtain its relation to the number of rotations. Movement of the curling stone from the release of delivery was recorded in the sequential images with the cameras located on the ceiling. Calibrations to remove lens aberration and to connect the imaging areas of two cameras were done prior to the experiment. The initial directions of the stone in each delivery were calculated as a reference line using the positions of the stone derived from the sequential images. Then the curl distance was measured as a length from the stop position of the stone perpendicular to the reference line, which was corrected as to convert the translation of the stone equivalent to distance between the hog line and the tee line. It was found that the curl distance decreases almost linearly as the number of rotations increases.
