Eyeball information estimation device, eyeball information estimation method, and eyeball information estimation program

An eyeball information estimation method comprising:

• an acquiring step of acquiring an image that includes a pupil of an eye of a subject and a Purkinje image of a light source on a corneal surface of the eye of the subject;
• a detecting step of detecting a center position of the pupil and a position of the Purkinje image;
• a selecting step of selecting which of first sight line angle calculation processing of calculating a sight line angle of the eye of the subject based on the center position of the pupil and the position of the Purkinje image, and second sight line angle calculation processing of calculating the sight line angle of the eye of the subject based on the center position of the pupil and an eyeball center position of the eye that is read from a storage unit and corresponds to the subject is to be executed;
• and
• a processing step of estimating an eyeball center position of the eye of the subject based on a three-dimensional face model determined based on the sight line angle and updating the eyeball center position of the storage unit, at least on a condition that a pupil reliability indicating a likelihood of being the pupil is higher than a predetermined first pupil threshold value, and a Purkinje reliability indicating a likelihood of being the Purkinje image is higher than a predetermined first Purkinje threshold value, in a case where the first sight line angle calculation processing is selected,
• wherein the selection step is configured to select the first sight line angle calculation processing in a case where the Purkinje reliability of the Purkinje image in the acquired image is higher than a second Purkinje threshold value lower than the first Purkinje threshold value, and selects the second sight line angle calculation processing in a case where the Purkinje reliability is equal to or lower than the second Purkinje threshold value.

A non-transitory computer readable medium, storing a program for causing a computer to execute:

• an acquiring step of acquiring an image that includes a pupil of an eye of a subject and a Purkinje image of a light source on a corneal surface of the eye of the subject,
• a detecting step of detecting a center position of the pupil and a position of the Purkinje image,
• a selecting step of selecting which of first sight line angle calculation processing of calculating a sight line angle of the eye of the subject based on the center position of the pupil and the position of the Purkinje image, and second sight line angle calculation processing of calculating the sight line angle of the eye of the subject based on the center position of the pupil and an eyeball center position of the eye that is read from a storage unit and corresponds to the subject is to be executed;
• and
• a processing step of estimating an eyeball center position of the eye of the subject based on a three-dimensional face model determined based on the sight line angle and updating the eyeball center position of the storage unit, at least on a condition that a pupil reliability indicating a likelihood of being the pupil is higher than a predetermined first pupil threshold value, and a Purkinje reliability indicating a likelihood of being the Purkinje image is higher than a predetermined first Purkinje threshold value, in a case where the first sight line angle calculation processing is selected,
• wherein the selection step is configured to select the first sight line angle calculation processing in a case where the Purkinje reliability of the Purkinje image in the acquired image is higher than a second Purkinje threshold value lower than the first Purkinje threshold value, and selects the second sight line angle calculation processing in a case where the Purkinje reliability is equal to or lower than the second Purkinje threshold value.