Apparatus, method, and non-transitory medium for optical stabilization and digital image registration in scanning light ophthalmoscopy
Apparatus, method, and non-transitory medium for optical stabilization and digital image registration in scanning light ophthalmoscopy. Scanning an object with measurement light. Acquire an image of the object to be examined based on return light from the object. Acquire information which indicates movement of the object to be examined based on a plurality of acquired images. Control the scanning based on the information which indicates the movement of the object to be examined. Performing registration of the plurality of images.
1. A method of obtaining an AO (Adaptive Optics) image of an area of a subject, the method comprising:
providing light from a light source;
a fast scanning step of scanning the light in a first direction by a first scanner to produce a first scanning line of light;
a slow scanning step of scanning the first scanning line of light in a second direction by a second scanner, wherein the second direction is substantially orthogonal to the first direction to produce a first scanning area, wherein a scanning rate of the slow scanning step is lower than a scanning rate of the fast scanning step;
an image constructing step of constructing an image with light from the first scanning area of the subject;
a position detecting step of detecting a relative change in a position of the first scanning area on the subject by analyzing the image constructed in the image constructing step;
a tracking step of tracking the first scanning area by controlling the second scanner according to the detected relative change in the position of the first scanning area; and
an AO image constructing step of constructing the AO image by adjusting a position of the image using the detected relative change in the position of the first scanning area.
2. The method of claim 1 , wherein,
the tracking step further comprises adjusting the second scanner in two orthogonal directions according to the detected relative change in the position of the first scanning area.
3. The method of claim 1 , wherein:
the tracking step comprises controlling an optical tracking system for adjusting the first scanning area in the first scanning direction according to the detected relative change in the position of the first scanning area.
4. The method of claim 1 , further comprising:
obtaining a wide image of the subject that includes the first scanning area of the subject a field of view of the AO image is smaller than a field of view of the wide image; and
wherein the wide image is used to detect the relative change in the position of the first scanning area as a reference image and the image constructed in the image constructing step is used as a target image.
5. The method of claim 1 , wherein,
analyzing the constructed image includes calculating a cross-correlation between a reference image and a target image to detect the relative change in the position of the first scanning area on the subject.
6. The method of claim 1 , wherein,
the relative change in the position of the first scanning area is decomposed into a first relative change in the first direction and a second relative change in the second direction;
the first relative change in the first direction is compensated for by adjusting the position of the image along an axis in the first direction when constructing the AO image; and
the second relative change in the second direction is compensated for by controlling the first scanning area of the second scanner in the second direction according to the second relative change.
7. The method of claim 6 , wherein,
the second relative change in the second direction is also compensated for by adjusting the position of the image along an axis in the second direction when constructing the AO image.
8. The method of claim 1 , wherein the AO image is one of a video image or an averaged image.
9. The method of claim 1 , wherein,
the relative change in the position of the first scanning area is decomposed into a first relative change in the first direction and a second relative change in the second direction; and
the second relative change in the second direction is compensated for by controlling the first scanning area of the second scanner in the second direction according to the second relative change and in the first direction according to the first relative change.
10. An apparatus for obtaining an AO (Adaptive Optics) image of an area of a subject, the apparatus comprising:
a light source providing light;
a first scanner configured to perform a fast scanning step of scanning the light in a first direction to produce a first scanning line of light;
a second scanner configured to perform a slow scanning step of scanning the first scanning line of light in a second direction, wherein the second direction is substantially orthogonal to the first direction to produce a first scanning area, wherein a scanning rate of the slow scanning step is lower than a scanning rate of the fast scanning step;
a processor configured to perform:
an image constructing step of constructing an image with light from the first scanning area of the subject;
a position detecting step of detecting a relative change in a position of the first scanning area on the subject by analyzing the image constructed in the image constructing step;
a tracking step of tracking the first scanning area by controlling the second scanner according to the detected relative change in the position of the first scanning area; and
an AO image constructing step of constructing the AO image by adjusting a position of the image using the detected relative change in the position of the first scanning area.