Multispectral imaging apparatus

• US 10,574,911 B2
• Filed: 06/15/2016
• Issued: 02/25/2020
• Est. Priority Date: 06/15/2015
• Status: Active Grant

• Current Assignee: Agrowing Ltd.
• Original Assignee: Agrowing Ltd.
• Inventors: Dvir, Ira
• Primary Examiner(s): Aggarwal, Yogesh K
• Application Number:
  US15/736,318
• Publication Number:
  US 20180176488A1
• Time in Patent Office: 1,350 Days
• Field of Search: 348335, 348340, 348345, 34834835, 348352
• CPC Class Codes: G02B 13/14 for use with infrared or ultraviolet radiation G02B13/008, G02B13/16 take precedence
• CPC Class Codes: G02B 13/146 with corrections for use in multiple wavelength bands, such as infrared and visible light, e.g. FLIR systems
• CPC Class Codes: G02B 23/18 for binocular arrangements focusing binocular pairs G02B7/06; adjusting pupillary distance of binocular pairs G02B7/12
• CPC Class Codes: G03B 17/14 interchangeably
• CPC Class Codes: G06T 3/14 Transformations for image registration, e.g. adjusting or mapping for alignment of images
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/75 by influencing optical camera components

Abstract

A lens compound for connecting to an interchangeable lens mount of a digital camera having a single image sensor, the lens compound including a body; a single mount connecting ring mounted on the body for connecting to the lens mount of the digital camera; at least two lenses of substantially identical focal length mounted in the body; and a different single or multi bandpass filter associated with each of the lenses, allowing the passage of at least one visible band and one non-visible band, selected from the group consisting of near infra-red bands and ultra violet bands of light, through the filters to the sensor; wherein the lenses are of substantially identical field of view and substantially identical image circle at a sensor plane of the image sensor.

Claims

1. A multispectral imaging apparatus for capturing multispectral images, comprising:

A lens compound for connecting to an interchangeable lens mount of a digital camera having a single image sensor, the lens compound comprising;

a body;

a single mount connecting ring mounted on said body for connecting to the lens mount of the digital camera;

at least two lenses of substantially identical focal length, substantially identical field of view and substantially identical image circle at a sensor plane of the camera for acquiring color matrices of digital images of an object through each lens, mounted in said body;

a different single or multi bandpass filter associated with each of said lenses, allowing the passage of at least one visible band and one non-visible band, selected from the group consisting of near infra-red bands and ultra violet bands of light, through the filters to the sensor; and

a processing platform for post-acquisition digital alignment of at least a pair of digital images of an object, including;

a processor for splitting the color matrix which was captured by the similar light band from the multi-band images acquired by the different lenses and matching the substantially identical light band matrices from each lens for post-acquisition digital alignment of the images acquired by all the lenses.

2. The multispectral imaging apparatus according to claim 1, wherein the filters are selected to allow the passage of at least four different bands of the spectrum through said lenses.

3. The multispectral imaging apparatus claim 1, wherein the filters are selected to allow the passage of one similar band of the spectrum through both lenses, enabling post acquisition alignment of color matrices of both lenses based on matching of the similar band acquired by both lenses.

4. The multispectral imaging apparatus according to claim 3, wherein chromatic aberration is corrected by at least one of:

positioning the lenses at slightly different distances from the sensor;

or

including, in at least one of the lenses, an optical element that aligns the size of the image circle of one lens with that of the other lens.

5. The multispectral imaging apparatus according to claim 1, further comprising a light blocking frame disposed between the lenses or attached to the sensor.

6. The multispectral imaging apparatus according to claim 5, wherein the light blocking frame is selected from the group including a masking window, a border, and a partition disposed between lenses or attached to the sensor, or a combination of these.

7. The multispectral imaging apparatus according to claim 1, wherein each said lens is positioned in front of a center of the portion of the sensor associated therewith.

8. The multispectral imaging apparatus according to claim 1, wherein said filter is implemented as at least one of the following:

a coating, a filter mounted in front of the lens, a filter mounted behind the lens, and a filter mounted above the portion of the sensor which senses the light passing through a particular lens.

9. The multispectral imaging apparatus according to claim 1, further comprising a single focus mechanism for simultaneously adjusting focus of all the lenses.

10. The multispectral imaging apparatus according to claim 1, further including at least one Porro prism design associated with each lens.

11. A method for capturing multispectral images and digitally aligning said images, the method comprising:

capturing images on a single image sensor through at least two lenses of substantially identical focal length, wherein the lenses are of substantially identical field of view and substantially identical image circle at a sensor plane;

each said lens being associated with a different single or multi bandpass filter;

passing at least one visible band and at least one non-visible band, through said filters to the sensor;

acquiring said images, through said filters which permit passage of a similar light band, by each of the lenses;

saving said captured images from the multiple lenses in a single image file;

splitting a matrix which was captured by the similar light band from the multi-band images acquired by the different lenses;

matching the substantially identical light band matrices from each lens; and

digitally aligning the images acquired by all the lenses utilizing the similar light band matrices.

12. The method according to claim 11, wherein the step of passing includes passing at least four different spectral bands through said filters.

13. The method according to claim 11, further comprising correcting chromatic aberration by at least one of:

positioning the lenses at unequal distances from the sensor, or including, in at least one of the lenses, an optical element that aligns the size of the image circle of one lens with that of the other lens.

14. The method according to claim 11, further comprising cropping the lenses to prevent overlap of images.

15. The method according to claim 11, further including independently calibrating focus for each lens.

16. The method according to claim 11, further comprising balancing exposure levels of said lenses by a method selected from the group including:

a) pre-setting size of apertures (F stops) of said lenses according to wavelengths for acquisition during a same exposure time;

b) Adding neutral density coating or filter to the VIS lens;

c) manually set apertures/iris setting/F stop.

17. The method according to claim 11, wherein said non-visible band is selected from the group consisting of near infra-red bands and near ultra violet bands of light.

18. A multi spectral camera comprising:

a digital camera having an interchangeable lens mount, a shutter and a single sensor; and

a replaceable lens compound including;

a body;

a single mount connecting ring mounted on said body for connecting to the lens mount of the digital camera;

at least two lenses of substantially identical focal length, substantially identical field of view and substantially identical image circle at a sensor plane of the camera mounted in said body, each said lens mounted with its focal center disposed in front of the center of its respective portion of the sensor;

a different single or multi bandpass filter associated with each of said lenses, allowing passage of at least one visible band and at least one non-visible band, selected from the group consisting of near infra-red bands and ultra violet bands of light, through said filters to the sensor;

a processing platform for post-acquisition digital alignment of at least a pair of digital images of an object, including;

a processor for splitting the color matrix which was captured by the similar light band from the multi-band images acquired by the different lenses and matching the substantially identical light band matrices from each lens for post-acquisition digital alignment of the images acquired by all the lenses.

19. The camera according to claim 18, wherein the filters are selected to allow the passage of at least four different bands of the spectrum through said lenses.

20. The camera according to claim 19, wherein chromatic aberration is corrected by at least one of:

positioning the lenses in the compound at unequal distances from the sensor so that focal point of each lens coincides with a focal plane of the sensor;

or

including in at least one of the lenses an optical element that aligns the size of the image circle of one lens with that of the other lens;

or

selecting said lenses with slightly different focal length, and disposing them in the compound with an identical angle of view and image circle.

21. The camera according to claim 18, further comprising a light blocking frame disposed between the lenses or attached to the sensor.

22. A method for providing post-acquisition digital alignment of at least a pair of digital images of an object, the method comprising:

acquiring digital images of the object, stored as color matrices, through each of at least two lenses of substantially identical focal length, of substantially identical field of view and substantially identical image circle at a sensor plane of at least one sensor;

each said lens being associated with a single or multi bandpass filter, such that each lens captures one light band similar to one light band captured by the other said lens and at least one light band different from the light bands captured by the other said lens;

splitting the color matrix which was captured by the similar light band from the multi-band images acquired by the different lenses; and

matching the substantially identical light band matrices from each lens for post-acquisition digital alignment of the images acquired by all the lenses.

23. The method according to claim 22, wherein the filters allow the passage of at least a visible and a non-visible band of light through the filters to the sensor.

24. The method according to claim 23, further comprising a flash light matching the pass band of the non-visible filter, arranged to illuminate an object for imaging.

25. The method according to claim 24, further comprising a second flash light matching the pass band of the visible filter, arranged to illuminate the object for imaging.

26. Apparatus for providing post-acquisition digital alignment of at least a pair of digital images of an object, the apparatus comprising:

at least two lenses of substantially identical focal length, of substantially identical field of view and substantially identical image circle at a sensor plane, for acquiring color matrices of digital images of an object through each lens;

each said lens being associated with a single or multi bandpass filter which includes one similar light band and at least one different light band; and

a processor for splitting the color matrix which was captured by the similar light band from the multi-band images acquired by the different lenses and matching the substantially identical light band matrices from each lens for post-acquisition digital alignment of the images acquired by all the lenses.

27. The apparatus according to claim 26, wherein the filters allow the passage of at least one visible and one non-visible band of light through the filters to the sensor.

28. The apparatus according to claim 27, further comprising a flash light matching the pass band of the non-visible filter arranged to illuminate the object during image acquisition.

29. The apparatus according to claim 28, further comprising a second flash light matching the pass band of the visible filter arranged to illuminate the object during image acquisition.

30. A multispectral imaging apparatus comprising:

a mobile processing platform;

at least two cameras integrated with the platform, each camera including;

at least one sensor;

a lens of substantially identical focal length, similar field of view and substantially similar image circle at the sensor plane of the camera for acquiring color matrices of digital images of an object through each lens;

at least one single or multi bandpass filter allowing the passage of at least one visible and one non-visible band of light through the filters to the sensor; and

a processing platform for post-acquisition digital alignment of at least a pair of digital images of an object, including;

a processor for splitting the color matrix which was captured by the similar light band from the multi-band images acquired by the different lenses and matching the substantially identical light band matrices from each lens for post-acquisition digital alignment of the images acquired by all the lenses.

31. The apparatus according to claim 30, further comprising a flash light matching the non-visible pass band of the filters, arranged to illuminate an object for imaging.

32. The apparatus of claim 31, further comprising a second flash light matching the visible pass band of the filters, arranged to illuminate the object for imaging.

33. The apparatus according to claim 31, wherein the flash light matching the non-visible pass band is a dedicated flash light.

34. The apparatus according to claim 30, wherein said at least one sensor includes two sensors integrated with the platform, each sensor associated with at least one of said lenses and at least one of said filters.

35. The apparatus according to claim 30, wherein all the lenses include a filter to capture at least one similar color band of the spectrum, enabling digital alignment of different color channels in the captured images.

36. The multispectral imaging apparatus according to claim 30, wherein each said filter is implemented as at least one of the following:

a coating, a filter mounted in front of the lens, a filter mounted behind the lens, and a filter mounted above the portion of the sensor which senses the light passing through a particular lens.

37. A method for capturing multispectral images and aligning said images, the method comprising:

capturing images by a multispectral imaging apparatus on a mobile processing platform through at least two lenses, at least two filters, and at least one sensor integrated with the platform;

wherein the at least two filters allow the passage of at least a visible and a non-visible (near infra-red or ultra violet) band of light through the filters to the sensor;

wherein the lenses are of substantially identical focal length, similar field of view and substantially identical image circle at a sensor plane;

each said lens being associated with a different single or multi bandpass filter;

passing at least one visible band and at least one non-visible band, selected from the group consisting of near infra-red bands and ultra violet bands of light, through said filters to the sensors;

passing at least one similar color band of the spectrum through each said lens, enabling digital alignment of different color channels in the captured images-;

acquiring images, through said filters which include a substantially identical light band, by each of the lenses;

splitting a matrix which received the substantially identical light band from the multi-band images acquired by the different lenses; and

utilizing the substantially identical light band matrix for post-acquisition digital alignment of the images acquired by all the lenses.

38. The method according to claim 37, further comprising illuminating an object to be imaged with a flash light matching the non-visible pass band.

39. The method according to claim 38, wherein the flash light is a dedicated flash light.