Abstract—When an eye is captured from the side, the position of the pupil on the surface of the eyeball in spherical form is recorded in a two-dimensional camera image. As a result, the visual changes corresponding to eyeball movements form a nonlinear shape. Consequently, the calibration method where 9 points in a grid form are gazed at in advance in the same way as for the conventional gaze estimation inhibits correct mapping from the two-dimensional imaging to the three-dimensional eyeball movements. In this study, the authors examined the method of gaze estimation. In this method, an examinee is shown 7 points as calibration fixation points and correction is performed by using the projection transformation matrix that is produced from the 6 points. The result confirmed that satisfactory estimation can be obtained by instructing an examinee to gaze at 7 calibration fixation points that are determined from the total of evaluation points in the preliminary test and also gaze at 6 points for obtaining a projective transformation matrix even if the pupil imaging camera is installed at the side of the eye.
 

Index Terms—calibration fixation points, the side of an eye, gaze estimation, pupil, camera, eyeball movements
 

Cite: Atsumu Naito and Kiyoshi Hoshino, "Proposal for Determining the Calibration Fixation Points for Achieving High-Precision Gaze Estimation with a Pupil Imaging Camera Installed at the Side of an Eye," Journal of Advances in Information Technology, Vol. 13, No. 5, pp. 462-469, October 2022.

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