Method for robust eye tracking and ophthalmologic apparatus therefor

A method of imaging an area of an eye of a subject, the method comprising:

• providing a light from a light source;
• a scanning step of scanning the light by scanners to scan the light on a scanning area;
• an image constructing step of constructing an image with light from the scanning area of the subject;
• a reference image setting step of setting an image of the subject as a reference;
• a position detecting step of detecting a relative change in a position of the scanning area on the subject by comparing the reference image and constructed image;
• an imaging area controlling step of controlling the scanning area according to the detected relative change in the position of the scanning area;
• an evaluation step to check accuracy of the position detection and change the controlling method according to the accuracy.

A method of imaging an area of a subject, the method comprising:

• providing a light from a light source;
• a scanning step of scanning the light by scanners to scan the light on a scanning area;
• an image constructing step of constructing an image with light from the scanning area of the subject;
• a reference image setting step of setting an image of the subject as a reference;
• a position detecting step of detecting a relative change in a position of the scanning area on the subject by comparing the reference image and constructed image;
• a large area scanning step and large area image constructing step;
• a large movement detecting step comparing large area reference image and large constructed image;
• an imaging area controlling step controlling the scanning area according to the detected relative change in the position of the scanning area;
• an evaluation step to check accuracy of the position detection of each position calculation step and switch position data to control the scanning area in the imaging area controlling step according to the accuracy.

An ophthalmic apparatus comprising:

• a first acquiring unit configured to acquire a reference AO (Adaptive Optics) image and a target AO image of an eye to be examined;
• a second acquiring unit configured to acquire a reference WF (Wide Field) image and a target WF image of the eye to be examined;
• a calculation unit configured to calculate first position information of the target AO image with respect to the reference AO image and second position information of the target WF image with respect to the reference WF image;
• and
• a control unit configured to control an acquiring position of the target AO image on the eye to be examined according to the first position information or the second position information based on a predetermined condition.

A method for controlling an ophthalmic apparatus, the method comprising:

• acquiring a reference AO (Adaptive Optics) image and a target AO image of an eye to be examined;
• acquiring a reference WF (Wide Field) image and a target WF image of the eye to be examined;
• calculating first position information of the target AO image with respect to the reference AO image and second position information of the target WF image with respect to the reference WF image;
• and
• controlling an acquiring position of the target AO image on the eye to be examined according to the first position information or the second position information based on a predetermined condition.