OPHTHALMOLOGIC APPARATUS AND CONTROL METHOD FOR THE SAME

• US 20120327365A1
• Filed: 03/08/2011
• Published: 12/27/2012
• Est. Priority Date: 03/12/2010
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Makihira, Tomoyuki
• Granted Patent: US 8,998,412 B2
• Time in Patent Office: Days
• US Class Current: 351/206
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: A61B 3/12 for looking at the eye fundus, e.g. ophthalmoscopes A61B3/13 takes precedence
• CPC Class Codes: G06T 2207/30041 Eye; Retina; Ophthalmic
• CPC Class Codes: G06T 2207/30101 Blood vessel; Artery; Vein; Vascular
• CPC Class Codes: G06T 7/0016 involving temporal comparison
• CPC Class Codes: G06T 7/248 involving reference images or patches

Abstract

A conventional method in which an amount of movement of an eye ball between acquired images is calculated by extracting characteristic images of the fundus and comparing the images is excellent in precision, reproducibility and stability, but requires time for image processing. The aforementioned problem can be solved by using a tracking apparatus including: a fundus imaging apparatus for acquiring a fundus image; and a measurement unit that extracts a characteristic image of a fundus image from a first fundus image captured by the fundus imaging apparatus, detects the characteristic image from a second fundus image that is different from the fundus image, and measures a position change in the fundus images from coordinates of the extracted characteristic image and the detected characteristic image in the respective fundus images, wherein a region in which the characteristic image is detected from the second fundus image is determined so that a region searched for the characteristic image from the first image includes the extracted characteristic image and is broader than a range of movement of the characteristic image resulting from movements of the eye ball within measurement time.

Claims

1. An ophthalmologic apparatus that measures a movement of an eye to be inspected, the apparatus comprising:

an image acquiring unit configured to acquire a plurality of fundus images of the eye to be inspected, at different times;

a determining unit configured to determine a partial region based on a range of an eye movement and at least one of the plurality of the fundus images;

a processing unit configured to perform processing, the processing being at least one of extraction and search of at least one characteristic image from the partial region; and

a measuring unit configured to measure the movement of the eye by using the at least one characteristic image.

2. The ophthalmologic apparatus according to claim 1, wherein the processing unit includes an extracting unit configured to extract at least one characteristic image from the partial region, and

wherein the processing unit further includes a searching unit configured to search at least one other fundus image, from among the plurality of fundus images, for an image similar to the extracted at least one characteristic image.

3. The ophthalmologic apparatus according to claim 2, wherein the determining unit sets is configured to determine a region in at least one of the plurality of fundus images, the region having a fixed width inward from an outer frame of the fundus image and/or a region in the fundus image, the region having a fixed width from a center of the fundus image, as a partial region.

4. The ophthalmologic apparatus according to claim 1, wherein the processing unit includes an extracting unit configured to extract at least one characteristic image from at least one of the plurality of fundus images, and

wherein the processing unit further includes a searching unit configured to search the partial region in at least one other fundus image, from among the plurality of fundus images, for an image similar to the extracted at least one characteristic image.

5. The ophthalmologic apparatus according to claim 4, wherein the determining unit determines a region in the at least one fundus image, the region including the extracted at least one characteristic image and having a fixed width outward from an outer frame of the characteristic image, as a partial region.

6. The ophthalmologic apparatus according to claim 1, wherein the determining unit determines a region in at least one of the plurality of fundus images, the region having a fixed width inward from an outer frame of the fundus image, as a first partial region,

wherein the determining unit includes an extracting unit configured to extract at least one characteristic image from the first partial region,

wherein the determining unit determines a region in the at least one fundus image, the region including the extracted at least one characteristic image and having a fixed width outward from the outer frame of the characteristic image, as a second partial region, and

wherein the processing unit includes a searching unit configured to search the second partial region for an image similar to the extracted at least one characteristic image.

7. The ophthalmologic apparatus according to claim 6, wherein the fixed width is longer than a distance that an eye to be inspected moves within a measurement time.

8. The ophthalmologic apparatus according to claim 7, comprising a unit configured to acquire information relating to an involuntary eye movement of the eye to be inspected,

wherein the processing unit is configured to determine the fixed width based on the acquired information relating to an involuntary eye movement.

9. The ophthalmologic apparatus according to claim 8, wherein the information relating to an involuntary eye movement is obtained according to an imaging condition selected from external fixation, internal fixation, affected eye and normal subject, age, time required for capturing all fundus images, and time required for capturing one fundus image.

10. The ophthalmologic apparatus according to claim 8, wherein the information relating to an involuntary eye movement is obtained according to the time required for capturing one fundus image.

11. The ophthalmologic apparatus according to claim 1, wherein the image acquiring unit is configured to acquire the plurality of fundus images based on return light from the eye to be inspected, the return light resulting from measurement light applied via a scanning unit, and

wherein the image acquiring unit includes a control device configured to control the scanning unit based on a position change in the plurality of fundus images.

12. The ophthalmologic apparatus according to claim 11, wherein the processing, the measurement, the control and the acquisition are repeatedly performed in this order.

13. The ophthalmologic apparatus according to claim 1, wherein the determining unit is configured to determine a plurality of regions in the partial image, and

wherein the processing unit extracts is configured to extract a plurality of characteristic images from each of the plurality of regions.

14. The ophthalmologic apparatus according to claim 1, wherein the at least one characteristic image includes an image of at least one of a branching and a crossing of a blood vessel in a fundus.

15. The ophthalmologic apparatus according to claim 1, wherein the image acquiring unit includes any of a fundus camera, a scanning laser ophthalmoscope, an optical coherence tomographic imaging apparatus and a visual field test apparatus.

16. The ophthalmologic apparatus according to claim 1, wherein the plurality of fundus images includes a plurality of SLO images;

and

wherein the ophthalmologic apparatus further comprises a unit configured to acquire a plurality of OCT images in association with the plurality of SLO images, respectively.

21. The ophthalmologic apparatus according to claim 5, wherein the determining unit determines a region including the similar region found by the searching unit and having a fixed width outward from an outer frame of the similar image, as a third partial region, and

wherein the searching unit further searches the third partial region for an image similar to the extracted at least one characteristic image.

25. The ophthalmologic apparatus according to claim 1, wherein the eye movement amount is obtained from an imaging condition.

26. The ophthalmologic apparatus according to claim 1, wherein the eye movement amount is obtained from imaging time.

27. The ophthalmologic apparatus according to claim 1, wherein the eye movement amount is obtained from a rate of acquiring the fundus image.

28. A non-transitory computer program for providing an ophthalmologic apparatus according to claim 1 via a computer.

17-20. -20. (canceled)

22-24. -24. (canceled)

29. A method for measuring a movement of an eye to be inspected, the method comprising the steps of:

acquiring a plurality of fundus images of the eye to be inspected, at different times;

performing processing including extraction of a characteristic image from each of at least two fundus images from among the plurality of acquired fundus images and calculation of a coordinate difference between the extracted characteristic images;

measuring a position change in the plurality of fundus images based on a result of the processing; and

determining a partial region based on an eye movement amount and at least one of the plurality of fundus images.

30. The method according to claim 29, wherein the step of performing processing includes the step of extracting at least one characteristic image from the partial region, and

wherein the step of performing processing further includes the step of searching at least one other fundus image, from among the plurality of acquired fundus images, for an image similar to the extracted at least one characteristic image.

31. The method according to claim 29, wherein the step of performing processing includes the step of extracting at least one characteristic image from at least one fundus image from among the plurality of acquired fundus images, and

wherein the step of performing processing further includes the step of searching the partial region in at least one other fundus image, from among the plurality of acquired fundus images, for an image similar to the extracted at least one characteristic image.

32. The method according to claim 29, wherein the step of performing processing includes the step of extracting at least one characteristic image from the partial region, and

wherein the step of performing processing further includes the step of searching the partial region in at least one other fundus image, from among the plurality of acquired fundus images, for an image similar to the extracted at least one characteristic image.

33. An ophthalmologic apparatus that measures a movement of an eye to be inspected, the apparatus comprising:

an image acquiring unit configured to acquire a plurality of fundus images of the eye to be inspected, at different times;

a determining unit configured to determine a partial region based on a range of an eye movement and at least one of the plurality of fundus images; and

an extracting unit configured to extract at least one characteristic image from the partial region.

34. An ophthalmologic apparatus that measures a movement of an eye to be inspected, the apparatus comprising:

an image acquiring unit configured to acquire a plurality of fundus images of the eye to be inspected, at different times;

a determining unit configured to determine a partial region based on a range of an eye movement and at least one of the plurality of fundus images; and

a searching unit configured to search the partial region for at least one characteristic image.

35. An ophthalmologic apparatus that measures a movement of an eye to be inspected, the apparatus comprising:

an image acquiring unit configured to acquire a plurality of fundus images of the eye to be inspected, at different times; and

a determining unit configured to determine a partial region based on a range of an eye movement and at least one of the plurality of fundus images.