Laser scanning digital camera with pupil periphery illumination and potential for multiply scattered light imaging

• US 8,488,895 B2
• Filed: 12/21/2009
• Issued: 07/16/2013
• Est. Priority Date: 05/31/2006
• Status: Active Grant

• Current Assignee: Indiana University Research & Technology Corporation (Indiana University)
• Original Assignee: Indiana University Research & Technology Corporation (Indiana University)
• Inventors: Muller, Matthew S., Elsner, Ann E., Petrig, Benno L.
• Primary Examiner(s): Kassa, Yosef
• Application Number:
  US12/643,491
• Publication Number:
  US 20100128221A1
• Time in Patent Office: 1,303 Days
• Field of Search: 382/117, 382/128, 382/274, 382/282, 382/307, 351/206, 351/207, 359/19
• US Class Current: 382/254
• CPC Class Codes: A61B 3/1025 for confocal scanning
• CPC Class Codes: G02B 21/0028 specially adapted for specific applications, e.g. for endoscopes, ophthalmoscopes, attachments to conventional microscopes
• CPC Class Codes: G02B 21/0048 scanning mirrors, e.g. rotating or galvanomirrors, MEMS mirrors
• CPC Class Codes: G02B 21/0068 arrangements using polarisation
• CPC Class Codes: G02B 21/008 Details of detection or image processing, including general computer control

Abstract

A portable, lightweight digital imaging device uses a slit scanning arrangement to obtain an image of the eye, in particular the retina. In at least one embodiment, a digital retinal imaging device includes an illumination source operable to produce a source beam, wherein the source beam defines an illumination pathway, a scanning mechanism operable to cause a scanning motion of the illumination pathway in one dimension with respect to a target, an optical element situated within the illumination pathway, the optical element operable to focus the illumination pathway into an illumination slit at a plane conjugate to the target, wherein the illumination slit is slit shaped, a first two dimensional detector array operable to detect illumination returning from the target and acquire one or more data sets from the detected illumination, wherein the returning illumination defines a detection pathway, and a shaping mechanism positioned within the illumination pathway, wherein the shaping mechanism shapes the source beam into at least one arc at a plane conjugate to the pupil. In at least one exemplary embodiment, the digital retinal imaging device is operable to minimize at least one aberration from the optical element or an unwanted reflection from the target or a reflection from a device.

Claims

1. A digital retinal imaging device comprising:

an illumination source operable to produce a source beam, wherein the source beam defines an illumination pathway;

an optical element situated within the illumination pathway, the optical element operable to focus the illumination pathway into an illumination slit at a plane conjugate to the target, wherein the illumination slit is slit shaped;

a shaping mechanism positioned within the illumination pathway, wherein the shaping mechanism shapes the source beam into at least one arc at a plane conjugate to a pupil;

a scanning mechanism operable to cause a scanning motion of the illumination pathway in one dimension with respect to a target; and

a first two dimensional detector array operable to detect illumination returning from the target and acquire one or more data sets from the detected illumination, wherein the returning illumination defines a detection pathway;

wherein the digital retinal imaging device is operable to minimize at least one aberration from the optical element or an unwanted reflection from the target or a reflection from a device.

2. The device of claim 1, wherein the first two dimensional detector array is a complementary metal-oxide conductor (CMOS).

3. The device of claim 1, wherein the first two dimensional detector array and the illumination slit are synchronized to detect a line by line scan of the target or an area by area scan of the target, thereby resulting in a confocal image, a multiply scattered light image, or a sharpened image.

4. The device of claim 1, wherein the optical element is selected from a group consisting of a slit aperture, a lens, a lens without an aperture, and a mirror.

5. The device of claim 1, further comprising an aperture within the illumination pathway operable to shape the illumination pathway, wherein the aperture is selected from a group consisting of an electronic aperture and a mechanical aperture.

6. The device of claim 1, wherein the shaping mechanism is selected from a group consisting of electro-optical components, and fiber-optics.

7. The device of claim 1, wherein the illumination pathway is shaped by increasing or decreasing the width of the slit shape, thereby resulting in improved image quality.

8. The device of claim 1, wherein the at least one arc is substantially ring-shaped.

9. The device of claim 1, wherein the illumination source comprises a geometrically defined source.

10. The device of claim 1, wherein the scanning element is operable to produce scanning illumination at the target of up to approximately 50 degrees, whereby the scanning illumination is defined by the illumination pathway and by movement of the scanning element.

11. The device of claim 1, wherein the detection pathway further comprises a detector aperture at the plane conjugate to the pupil, wherein the detector aperture is operable to reduce at least one reflection from the device or the target.

12. The device of claim 11, wherein the detector aperture is selected from a group consisting of an electro-optical aperture and a mechanical aperture.

13. The device of claim 11, wherein the detector aperture is operable to block a portion of the source beam, wherein the portion of the source beam is selected from a group consisting of a reflected illumination from the optical element, a scattered illumination from the optical element, a reflected illumination from the target, and a scattered illumination from the target.

14. The device of claim 1, further comprising a focusing system in the illumination pathway, wherein the focusing system comprises one or more focusing elements, the one or more focusing elements selected from a group of one or more refractive elements and one or more reflective elements, and whereby the focusing system is operable to adjust a physical pathlength between the target and the scanning mechanism.

15. The device of claim 1, wherein the illumination source is an infrared illumination source.

16. The device of claim 1, wherein an image developed with the one or more data sets is further modified by weighting the one or more data sets in such a manner that signal to noise ratio, image sharpness, and/or other image quality variables are maximized.

17. The device of claim 1, further comprising a second two dimensional detector array in the detection pathway operable to function with the first two dimensional detector array such that stereo imaging and polarimetry can be performed.

18. The device of claim 1, wherein the digital retinal device is operable to be synchronized for simultaneous indirect light imaging with a leading electronic aperture or lagging electronic aperture.

19. The device of claim 1, further comprising a processor operable to combine the one or more data sets in a weighted manner.

20. The device of claim 1, further comprising a barrier filter operable to reject selected wavelengths of the returning illumination, wherein rejected wavelengths do not reach the first two dimensional detector array.

21. A digital imaging device comprising:

an illumination source operable to produce a source beam, wherein the source beam defines an illumination pathway;

an optical element situated within the illumination pathway, the optical element operable to focus the illumination pathway into an illumination slit at a plane conjugate to the target, wherein the illumination slit is slit shaped;

a shaping mechanism positioned within the illumination pathway, wherein the shaping mechanism shapes the source beam into at least one arc at a plane conjugate to a pupil;

a scanning mechanism operable to cause a scanning motion of the illumination pathway in one dimension with respect to a target;

a first two dimensional detector array operable to detect illumination returning from the target and acquire one or more data sets from the detected illumination, wherein the returning illumination defines a detection pathway, wherein the first two dimensional detector array and illumination slit are synchronized to detect a line by line scan of the target or an area by area scan of the target; and

a dispersive element used in conjunction with the first two dimensional detector array to spatially filter a light remitted from the target by wavelength;

wherein the digital imaging device is operable to minimize at least one aberration from the optical element or an unwanted reflection from the target or a reflection from a device.

22. The device of claim 21, wherein the digital imaging device is operable to be synchronized with a leading or lagging electronic aperture for selection of a spectral component of the light remitted from the target.

23. The device of claim 21, wherein the digital imaging device is operable to be synchronized with a leading or lagging electronic aperture for selection of a spectral component of the light fluoresced from the target.

24. The device of claim 21, further comprising a processor operable to combine the one or more data sets in a weighted manner.

25. The device of claim 21, wherein the shaping mechanism is selected from a group consisting of electro-optical components, and fiber-optics.

26. The device of claim 21, wherein the at least one arc is substantially ring-shaped.

27. The device of claim 21, wherein the illumination source comprises a geometrically defined source.

28. The device of claim 21, further comprising a barrier filter operable to reject selected wavelengths of the remitted light, wherein rejected wavelengths do not reach the detector.

29. The device of claim 21, further comprising a second two dimensional detector array in the detection pathway operable to function with the first two dimensional detector array such that stereo imaging and polarimetry can be performed.

30. A digital imaging device comprising:

an illumination source operable to produce a source beam, wherein the source beam defines an illumination pathway;

an optical element situated within the illumination pathway, the optical element operable to focus the illumination pathway into an illumination slit, wherein the illumination slit is slit shaped;

a scanning mechanism operable to cause a scanning motion of the illumination pathway in one dimension with respect to a target;

a first two dimensional detector array operable to detect illumination returning from the target and acquire one or more data sets from the detected illumination, wherein the returning illumination defines a detection pathway, wherein the two dimensional detector and illumination slit are synchronized to detect a line by line scan of the target or an area by area scan of the target; and

a dispersive element used in conjunction with the two dimensional detector to spatially filter a light remitted from the target by wavelength;

wherein the digital imaging device is operable to minimize at least one aberration from the optical element or an unwanted reflection from the target or a reflection from a device.

31. The device of claim 30, wherein the digital imaging device is operable to be synchronized with a leading or lagging electronic aperture for selection of a spectral component of the light remitted from the target.

32. The device of claim 30, wherein the digital imaging device is operable to be synchronized with a leading or lagging electronic aperture for selection of a spectral component of the light fluoresced from the target.

33. The device of claim 30, further comprising a processor operable to combine the one or more data sets in a weighted manner.

34. The device of claim 30, wherein the illumination source comprises a geometrically defined source.

35. The device of claim 30, further comprising a second two dimensional detector array in the detection pathway operable to function with the first two dimensional detector array such that stereo imaging and polarimetry can be performed.

36. The device of claim 30, further comprising a barrier filter operable to reject selected wavelengths of the remitted light, wherein rejected wavelengths do not reach the first two dimensional detector array.

37. The device of claim 30, wherein the shaping mechanism is selected from a group consisting of electro-optical components, and fiber-optics.