COMPACT LIGHT SENSORS WITH SYMMETRICAL LIGHTING

• US 20160249810A1
• Filed: 05/10/2016
• Published: 09/01/2016
• Est. Priority Date: 03/21/2014
• Status: Active Grant

• Current Assignee: Hypermed Imaging Incorporated
• Original Assignee: Hypermed Imaging Incorporated
• Inventors: Meenen, Peter, Darty, Mark Anthony, Tilleman, Michael, Yudovsky, Dmitry
• Granted Patent: US 9,526,427 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2090/309 using white LEDs
• CPC Class Codes: A61B 2562/0238 Optical sensor arrangements for performing transmission measurements on body tissue
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/0079 using mirrors, i.e. for self-examination
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/443 Evaluating skin constituents, e.g. elastin, melanin, water
• CPC Class Codes: A61B 5/444 Evaluating skin marks, e.g. mole, nevi, tumour, scar
• CPC Class Codes: G01J 2003/106 the two sources being alternating or selectable, e.g. in two ranges or line:continuum
• CPC Class Codes: G01J 2003/1239 and separate detectors
• CPC Class Codes: G01J 2003/2826 Multispectral imaging, e.g. filter imaging
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/0294 Multi-channel spectroscopy
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/2823 Imaging spectrometer
• CPC Class Codes: G02B 27/106 for splitting or combining a plurality of identical beams or images, e.g. image replication
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 23/16 Optical arrangements associated therewith, e.g. for beam-splitting or for colour correction
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/63 : by using electronic viewfinders
• CPC Class Codes: H04N 23/74 : by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 25/135 : based on four or more different wavelength filter elements

Abstract

Provided are methods and systems for concurrent imaging at multiple wavelengths. In one aspect, an imaging device includes at least one objective lens configured to receive light backscattered by an object, a plurality of pixel array photo-sensors, a plurality of bandpass filters covering respective photo-sensors, where each bandpass filter is configured to allow a different respective spectral band to pass through the filter, and a beam steering assembly in optical communication with the at least one objective lens and the photo-sensors. The beam steering assembly directs light received by at least one objective lens from the tissue of a subject to at least one pixel array photo-sensor in the plurality of pixel array photo-sensors.

Claims

1. An imaging device, comprising:

A) a housing having an exterior and an interior;

B) at least one objective lens attached to or within the housing,

C) a plurality of light source sets radially disposed on the exterior of the housing about the at least one objective lens, wherein

each light source set in the plurality of light source sets comprises a first light source that emits light that is substantially limited to a first spectral range and a second light source that emits light that is substantially limited to a second spectral range,

each light source in each light source set in the plurality of light source sets is offset from the at least one objective lens and positioned so that light from each respective light source is backscattered by a tissue of a subject and then passed through the at least one objective lens, and

each light in each light source set has a different radial position with respect to the at least one objective lens;

D) a plurality of pixel array photo-sensors within the housing;

E) an optical assembly within the interior of the housing, the optical assembly in optical communication with the at least one objective lens, the optical assembly characterized by further directing light received by at least one objective lens from the tissue of the subject to at least one pixel array photo-sensor in the plurality of pixel array photo-sensors;

F) a plurality of multi-bandpass filters, wherein each respective multi-bandpass filter in the plurality of multi-bandpass filters covers a corresponding pixel array photo-sensor in the plurality of pixel array photo-sensors thereby selectively allowing a different corresponding spectral band of light, from the light received by the at least one object lens and redirected by the optical assembly, to pass through to the corresponding pixel array photo-sensor; and

G) a controller, wherein at least one program is non-transiently stored in the controller and executable by the controller, the at least one program causing the controller to perform the method of;

i) firing a first light in each light source set in the plurality of light source sets for a first period of time while not firing the second light source in each light source set,

ii) collecting a first set of images during the first period of time using at least a first subset of the plurality of pixel array photo-sensors,

iii) firing a second light in each light source set in the plurality of light source sets for a second period of time while not firing the first light source in each light source set, and

iv) collecting a second set of images during the second period of time using at least a second subset of the plurality of pixel array photo-sensors.

2. The imaging device of claim 1, wherein the optical assembly element comprises a plurality of beam splitters in optical communication with the at least one objective lens and the plurality of pixel array photo-sensors,

each respective beam splitter in the plurality of beam splitters is configured to split the light received by the at least one objective lens into at least two optical paths,

a first beam splitter in the plurality of beam splitters is in direct optical communication with the at least one objective lens and a second beam splitter in the plurality of beam splitters is in indirect optical communication with the at least one objective lens through the first beam splitter, and

the plurality of beam splitters collectively split light received by the at least one objective lens into a plurality of optical paths, wherein each respective optical path in the plurality of optical paths is configured to direct light to a corresponding pixel array photo-sensor in the plurality of pixel array photo-sensors through the respective multi-bandpass filter covering the corresponding pixel array photo-sensor.

3. The imaging device of claim 1, wherein

the optical assembly comprises a beam steering element characterized by a plurality of operating modes, each respective operating mode in the plurality of operating modes causing the beam steering element to be in optical communication with a different pixel array photo-sensor in the plurality of pixel array photo-sensors,

a first subset of the plurality of operating modes are associated with firing a first light in each light source set in the plurality of light source sets in the first period of time, and

a second subset of the plurality of operating modes are associated with firing a second light in each light source set in the plurality of light source sets in the second period of time.

4. The imaging device of claim 1, wherein the plurality of multi-bandpass filters are dual bandpass filters.

5. The imaging device of claim 1, wherein

the plurality of light source sets consist of two light source sets, and

a first light source set in the two light source sets is arranged with respect to the at least one objective lens so that the first light source of the first light source set opposes the first light source of the second light source set in the two light source sets, and the second light source of the first light source set opposes the second light source of the second light source set.

6. The imaging device of claim 1, wherein

the plurality of light source sets consist of four light source sets, and

a first light source set in the four light source sets is arranged with respect to the at least one objective lens so that the first light source of the first light source set opposes the first light source of a second light source set in the four light source sets, and the second light source of the first light source set opposes the second light source of the second light source set.

7. The imaging device of claim 1, wherein

the plurality of light source sets consist of 2N light source sets, wherein N is a positive integer, and

a first light source set in the 2N light source sets is arranged with respect to the at least one objective lens so that the first light source of the first light source set opposes the first light source of the second light source set in the 2N light source sets, and the second light source of the first light source set opposes the second light source of the second light source set.

8. The imaging device of claim 1, wherein

the plurality of light source sets collectively comprises a plurality of first light sources and a plurality of second light sources,

the first plurality of first light sources are uniformly radially distributed about the at least one objective lens, and

the plurality of second light sources are uniformly radially distributed about the at least one objective lens.

9. The imaging device of claim 8, wherein the plurality of first light sources are radially offset from the plurality of second light sources.

10. The imaging device of claim 8, wherein the plurality of light source sets consists of three light source sets.

11. The imaging device of claim 8, wherein the plurality of light source sets comprises four or more light source sets.

12. The imaging device of claim 1, wherein

the first light source of each light source set in the plurality of light source sets is a first multi-spectral light source covered by a first bandpass filter, wherein the first bandpass filter substantially blocks all light emitted by the first light source other than the first spectral range, and

the second light source of each light source set in the plurality of light source sets is a second multi-spectral light source covered by a second bandpass filter, wherein the second bandpass filter substantially blocks all light emitted by the second light source other than the second spectral range.

13. The imaging device of claim 12, wherein the first multi-spectral light source is a first white light emitting diode and the second multi-spectral light source is a second white light emitting diode.

14. The imaging device of claim 1, wherein each respective multi-bandpass filter in the plurality of multi-bandpass filters is configured to selectively allow light corresponding to either of two discrete spectral bands to pass through to the corresponding pixel array photo-sensor.

15. The imaging device of claim 14, wherein:

a first of the two discrete spectral bands corresponds to a first spectral band that is represented in the first spectral range and not in the second spectral range; and

a second of the two discrete spectral bands corresponds to a second spectral band that is represented in the second spectral range and not in the first spectral range.

16. The imaging device of claim 1, wherein the first spectral range is substantially non-overlapping with the second spectral range.

17. The imaging device of claim 1, wherein the first spectral range is substantially contiguous with the second spectral range.

18. The imaging device of claim 1, wherein

the first spectral range comprises 520 nm, 540 nm, 560 nm and 640 nm wavelength light and does not include 580 nm, 590 nm, 610 nm and 620 nm wavelength light, and

the second spectral range comprises 580 nm, 590 nm, 610 nm and 620 nm wavelength light and does not include 520 nm, 540 nm, 560 nm and 640 nm wavelength light.

19. The imaging device of claim 3, the optical assembly further comprising a plurality of beam steering elements, each respective beam steering element configured to direct light in a respective optical path to a respective pixel array photo-sensor, of the plurality of pixel array photo-sensors, corresponding to the respective optical path.

20. The imaging device of claim 19, wherein

each one of a first subset of the plurality of beam steering elements is configured to direct light in a first direction that is perpendicular to the direction of the light received by the plurality of beam steering elements from the at least one objective lens, and

each one of a second subset of the plurality of beam steering elements is configured to direct light in a second direction that is perpendicular to the light received by the plurality of beam steering elements and opposite to the first direction.

21. The imaging device of claim 1, wherein

the first set of images includes, for each respective pixel array photo-sensor in the plurality of pixel array photo-sensors, an image corresponding to a first spectral band transmitted by the corresponding multi-bandpass filter, wherein the light falling within the first spectral range includes light falling within the first spectral band of each multi-bandpass filter in the plurality of multi-bandpass filters, and

wherein the second set of images includes, for each respective pixel array photo-sensor in the plurality of pixel array photo-sensors, an image corresponding to a second spectral band transmitted by the corresponding multi-bandpass filter, wherein the light falling within the second spectral range includes light falling within the second spectral band of each multi-bandpass filter in the plurality of multi-bandpass filters.

22. The imaging device of claim 21, wherein

each respective pixel array photo-sensor in the plurality of pixel array photo-sensors is a pixel array that is controlled by a corresponding shutter mechanism that determines an image integration time for the respective pixel array photo-sensor, and

a first pixel array photo-sensor in the plurality of pixel array photo-sensors is independently associated with a first integration time for use during the collecting ii) and a second integration time for use during the collecting iv), wherein the first integration time is independent of the second integration time.

23. The imaging device of claim 2, wherein each beam splitter in the plurality of beam splitters exhibits a ratio of light transmission to light reflection of about 50:

50.

24. The imaging device of claim 23, wherein each respective beam splitter in the plurality of beam splitters is a wavelength-independent beam splitters.

25. The imaging device of claim 1, wherein each image in the plurality of images is a multi-pixel image of the tissue of the subject, the method further comprising:

v) combining each image in the plurality of images, on a pixel by pixel basis, to form a composite image.

26. The imaging device of claim 1, wherein,

the imaging device is portable and powered independent of a power grid during first period of time and the second period of time,

the plurality of light source sets collectively comprises a plurality of first light sources and a plurality of second light sources,

the plurality of first light sources collectively provide at least 80 watts of illuminating power during the firing i),

the plurality of second light sources collectively provide at least 80 watts of illuminating power during the firing iii), and

the imaging device further comprises a capacitor bank in electrical communication with each first light source and each second light source, wherein a capacitor in the capacitor bank has a voltage rating of at least 2 volts and a capacitance rating of at least 80 farads.

27. The imaging device of claim 1, wherein the two discrete bands of a multi-bandpass filter in the plurality of multi-bandpass filters are separated by at least 60 nm.

28. The imaging device of claim 1, wherein the imaging device is portable and electrically independent of a power grid during the firing i) and the firing iii), and wherein the firing i) occurs for less than 300 milliseconds and the firing iii) occurs for less than 300 milliseconds.

29. The imaging device of claim 2, further comprising:

a first circuit board positioned on a first side of the optical assembly, wherein a first pixel array photo-sensor and a third pixel array photo-sensor in the plurality of pixel array photo-sensors are coupled to the first circuit board; and

a second circuit board positioned on a second side of the optical assembly opposite to the first side, wherein the second circuit board is substantially parallel with the first circuit board, wherein a second pixel array photo-sensor and a fourth pixel array photo-sensor in the plurality of pixel array photo-sensors are coupled to the second circuit board, and

wherein;

the first beam splitter is configured to split light received from the at least one objective lens into a first optical path and a second optical path, wherein the first optical path is substantially collinear with an optical axis defined by the light incoming from at least one objective lens to the optical assembly, and the second optical path is substantially perpendicular to the optical axis,

the second beam splitter is configured split light from the first optical path into a third optical path and a fourth optical path, wherein the third optical path is substantially collinear with the first optical path, and the fourth optical path is substantially perpendicular to the optical axis,

a third beam splitter in the plurality of beam splitters is configured to split light from the second optical path into a fifth optical path and a sixth optical path, wherein the fifth optical path is substantially collinear with the second optical path, and the sixth optical path is substantially perpendicular to the second optical path, and wherein the optical path assembly further comprises;

a first beam steering element configured to deflect light from the third optical path perpendicular to the third optical path and onto the first pixel array photo-sensor coupled to the first circuit board,

a second beam steering element configured to deflect light from the fourth optical path perpendicular to the fourth optical path and onto the second pixel array photo-sensor coupled to the second circuit board,

a third beam steering element configured to deflect light from the fifth optical path perpendicular to the fifth optical path and onto the third pixel array photo-sensor coupled to the first circuit board, and

a fourth beam steering element configured to deflect light from the sixth optical path perpendicular to the sixth optical path and onto the fourth pixel array photo-sensor coupled to the second circuit board.

30. The imaging device of claim 29, wherein

a first multi-bandpass filter in the plurality of multi-bandpass filters is positioned in the third optical path between the first beam splitter and the first pixel array photo-sensor,

a second multi-bandpass filter in the plurality of multi-bandpass filters is positioned in the fourth optical path between the second beam splitter and the second pixel array photo-sensor,

a third multi-bandpass filter in the plurality of multi-bandpass filters is positioned in the fifth optical path between the third beam splitter and the third pixel array photo-sensor, and

a fourth multi-bandpass filter in the plurality of multi-bandpass filters is positioned in the sixth optical path between the fourth beam splitter and the fourth pixel array photo-sensor.

31. The imaging device of claim 29, further comprising a polarizing filter disposed along the optical axis.

32. The imaging device of claim 29, wherein the polarizing filter is adjacent to the at least one objective lens and before the first beam splitter along the optical axis.

33. The imaging device of claim 29, wherein the first beam steering element is a folding prism.

34. The imaging device of claim 29, wherein each respective beam splitter and each respective beam steering element is oriented along substantially the same plane.

35. The imaging device of claim 29, wherein the first beam splitter, the second beam splitter, and the third beam splitter each exhibits a ratio of light transmission to light reflection of about 50:

50.

36. The imaging device of claim 1, wherein

the plurality of light source sets collectively comprises a plurality of first light sources and a plurality of second light sources,

each light source in the plurality of first light sources is a white light-emitting diode covered by a respective first light source filter that blocks light emitted by the white light-emitting diode other than the first spectral range, and

each light source in the plurality of second light sources is a white light-emitting diode covered by a respective second light source filter that blocks light emitted by the white light-emitting diode other than the second spectral range.

37. The imaging device of claim 1, wherein

each light source in each light source set is covered by a first polarizer, and

the at least one objective lens is covered by a second polarizer.

38. The imaging device of claim 3, wherein the beam steering element comprises a mirror mounted on an actuator, the actuator having the plurality of operating modes.

39. The imaging device of claim 38, wherein the mirror is a single-surface mirror.

40. The imaging device of claim 38, wherein the mirror is a two-axis micro electro-mechanical (MEMS) mirror.

41. The imaging device of claim 3, wherein the beam steering element comprises an array of micromirrors.

42. The hyperspectral/multispectral imaging device of claim 41, wherein the array of micromirrors comprises a digital micromirror device.

43. The imaging device of claim 3, wherein the plurality of pixel array photo-sensors comprises at least four pixel array photo-sensors.

44. The imaging device of claim 1, wherein each respective pixel array photo-sensor in the plurality of pixel array photo-sensors is used for detecting a different frequency of radiation.

45. The imaging device of claim 3, wherein the collecting ii) comprises placing the beam steering element in an operating mode in the plurality of operating modes that causes the beam steering element to be in optical communication with a corresponding pixel array photo-sensor in the plurality of pixel array photo-sensors.

46. The imaging device of claim 1, further comprising a housing display disposed on the exterior of the housing, the housing display in electronic communication with the controller, wherein the method further comprises displaying an image captured by a respective pixel array photo-sensor in the plurality of pixel array photo-sensors on the housing display.

47. The imaging device of claim 1, wherein

the plurality of light source sets comprises two light source sets, and

a first light source set in the two light source sets is arranged with respect to the at least one objective lens so that a first light source of the first light source set opposes a first light source of the second light source set, a second light source of the first light source set opposes a second light source of the second light source set, and a third light source of the first light source set opposes a third light source of the second light source set with respect to the at least one objective lens, and the method further comprises:

iii) firing a third light in each light source set in the plurality of light source sets for a third period of time while not firing the first light source or the second light source in each light source set, and

iv) collecting a third set of images during the third period of time using at least a third subset of the plurality of pixel array photo-sensors.

48. The imaging device of claim 47, wherein

a fourth light source in the first light source set opposes a fourth light source of the second light source set in the two light source sets with respect to the at least one objective lens, and the method further comprises:

v) firing a fourth light in each light source set in the plurality of light source sets for a fourth period of time while not firing the first light source, the second light source, or the third light source in each light source set, and

vi) collecting a fourth set of images during the fourth period of time using at least a fourth subset of the plurality of pixel array photo-sensors.

49. The imaging device of claim 1 wherein each light source set in the plurality of light source sets consists of two light sources.

50. The imaging device of claim 1, wherein each light source set in the plurality of light source sets comprises 2+N light sources, wherein N is a positive integer.