AU2002225317A1 - System and method for wide field imaging of body lumens - Google Patents

Description

SYSTEM AND METHOD FOR WIDE FIELD IMAGING OF BODY

LUMENS

FIELD OF THE INVENTION

The present invention relates to the field of in vivo imaging. More

specifically, the present invention relates to a system and method for wide angle

viewing or imaging of body lumens.

BACKGROUND OF THE INVENTION

In vivo imaging greatly enhances a practitioner's ability to safely and easily

view internal body features and occurrences with minimal intrusion. A body lumen,

typically a voluminous cavity, is most effectively viewed or imaged when a wide

angle of viewing or imaging is obtained.

Wide angle optics usually employ a single optical path which includes a

complicated set of alternating differently shaped mirrors and lenses. Some methods

for photographing a wide field involve alignment of film and imaging devices to

cover multiple fields of view.

To date, there exists no simple method or system for wide angle viewing or

imaging of body lumens. SUMMARY OF THE INVENTION

The present invention provides a system and method for wide angle

imaging of body lumens. A wide angle of imaging is obtained by employing a

plurality of optical paths coordinated to cover a wider angle than that covered by a

single optical path.

An optical path, in the present invention, is the course followed by light

rays incident on an endo - luminal site and remitted from it onto an imager, such as

a CMOS imager. Thus, an optical path, according to an embodiment of the

invention, includes at least an endo- luminal site and an imager. The optical path

may further include means for collecting and directing light rays, such as lenses and

mirrors, for collecting the remitted light and directing and/or focusing it upon the

imager.

Each optical path comprises at least one imager however, the same imager

can be part of several different optical paths, where remitted light from several

different endo - luminal sites is directed from the different sites onto the same

imager through different optical paths.

The system according to an embodiment of the invention comprises at least

one imager and an optical system having a plurality of optical paths for imaging

images from within the body lumen onto the at least one imager. In one embodiment

the system is inserted into the body lumen for obtaining a wide angle of view of the

body lumen. The obtained images may be stored in the imager or in an additional

memory device. The system may further include at least one transmitter for transmitting signals to a receiving system, such that the images can be received and

analyzed in real time. The receiving system may include a recording/processing

device for subsequent analysis.

The system, according to an embodiment of the invention, may be

incorporated in or attached on to a device that is configured for being inserted into

body lumens such as an endoscope, a needle, stent or a device that can pass through

the gastrointestinal (GI) tract.

In one embodiment of the invention the system comprises a single imager

and a single transmitter and a plurality of optical paths. In this embodiment a

plurality of narrow field images are obtained on the single imager and are then

combined into a single image having a wider angle field than any of the narrow field

images.

In another embodiment of the invention the system comprises a plurality of

imagers and at least one transmitter transmitting in a single channel of transmission

or in multiple channels. In this embodiment the imagers are positioned such that

they capture images of different portions of the body lumen. A combined image of

the images captured by the different imagers shows all the individually imaged

portions, thereby covering a wide field.

For example, a wide field of view of any section of the GI tract can be

obtained by encapsulating the system of the invention in a device capable of passing

through the entire GI tract, such as a capsule similar to the swallowable capsule

described in US Patent Number 5,604,531 or WO 01/65995. US Patent Number 5,604,531 and WO 01/65995, which are assigned to the common assignee of the

present application, are hereby incorporated by reference.

One imager and its optical path can be positioned at one end of the device

and another imager and its optical path at another end of the device. Alternatively,

imagers and their optical paths can be positioned in a circle facing outwards on the

circumference of the device.

In yet another embodiment of the invention the system comprises a

plurality of imagers, each having an optical path, wherein each imager and its

optical path is partitioned off from its neighboring imagers. In this embodiment

interference between imager operations is greatly reduced.

The present invention further provides a device for imaging a body lumen.

The device, according to an embodiment of the invention, comprises the system of

the invention. In one embodiment the device can be inserted into the GI tract, for

viewing specific regions of the GI tract, such as an endoscope, or for viewing the

entire GI tract, such as a swallowable capsule.

The method for obtaining a wide field image of a body lumen, according to

an embodiment of the invention, comprises the following steps: 1. inserting into a

body lumen a system comprising at least one imager for obtaining images from

within the body lumen and a plurality of optical paths; 2. obtaining a plurality of

images from within the body lumen. The method may include a further step of

transmitting signals from the imager, a further step of receiving the transmitted signals and a further step of combining the plurality of images into a single image.

The obtained images may be stored in a memory device for further analysis.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully from

the following detailed description taken in conjunction with the appended drawings

in which:

Figure 1A is a schematic longitudinal cross section view of a device

comprising the system comprising a single imager, according to an embodiment of

the invention;

Figure IB is a schematic radial cross section view of the device shown in

Fig. 1A;

Figure 1C is a more detailed view of the imager shown in Fig. IB;

Figure 2A is a schematic longitudinal cross section view of the system

comprising five optical paths, according to an embodiment of the invention;

Figure 2B is a schematic radial cross section view of the system shown in

Fig. 2A;

Figure 3 is a schematic presentation of the combining of four images to a

single combined image, according to an embodiment of the invention;

Figure 4 is a schematic longitudinal cross section view of a device

comprising the system that comprises front and rear optical paths, according to an

embodiment of the invention; Figure 5 is a schematic radial cross section view of the system comprising a

plurality of imagers, according to an embodiment of the invention;

Figure 6 is a schematic longitudinal cross section view of a device

comprising the system comprising a plurality of optical paths partitioned off from

each other, according to an embodiment of the invention; and

Figure 7 is a schematic radial cross section view of a device comprising a

system that comprises a plurality of optical paths partitioned off from each other,

according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The system and method, according to an embodiment of the present

invention, enable wide angle imaging of body lumens. The wide angle of view is

obtained by imaging partially overlapping or non overlapping portions of the body

lumen, using a plurality of optical paths. The images of the body lumen portions

may be combined to a single image.

The imaging of different portions of the body lumen, which may or may not

be simultaneous, is done by employing a plurality of optical paths, each of which

covers a different portion of the body lumen. In accordance with different

embodiments of the invention, and as will be shown in the figures, light rays may be

collimated through the different optical paths to a single imager or to a plurality of

imagers. The different optical paths may or may not be separated from each other by

a physical partition.

A separate transmitter and channel of transmission may be assigned to each

imager for simultaneous transmitting of signals from the body lumen.

Alternatively, the output of several imagers may be combined over a single

transmitter and channel of transmission e.g. by using different carrier frequencies.

According to one embodiment, the combination of information from the different

imagers over the single channel may be done either by selecting a bit from a

different imager each time, thus transmitting all the images almost simultaneously,

or by transmitting image after image. The system according to an embodiment of the invention comprises a

plurality of optical paths and at least one imager for endo-luminal imaging. In one

embodiment the system may be incorporated in or attached to any device or probe

suitable for being inserted into a body lumen, such as at the tip of a needle, on the

inserted end of an endoscope or in a swallowable capsule. In one embodiment the

system is positioned behind an optical window.

In the following description, various aspects of the present invention will be

described. For purposes of explanation, specific configurations and details are set

forth in order to provide a thorough understanding of the present invention.

However, it will also be apparent to one skilled in the art that the present invention

may be practiced without the specific details presented herein. Furthermore, well

known features may be omitted or simplified in order not to obscure the present

invention.

A swallowable capsule comprising a video camera for imaging the GI tract

is described in the above mentioned US Patent Number 5,604,531 and WO

01/65995. A capsule that may comprise similar elements to the capsules described

in US Patent Number 5,604,531 and WO 01/65995 but that comprises a plurality of

optical paths, is schematically shown in Fig. 1. The capsule 10 comprises

illumination sources 13, such as light emitting diods (LEDs), a system 19 including

lenses 11 and mirrors 18, all positioned behind optical window 12, an imager 14,

such as a CMOS imager for obtaining images from within the GI tract, power

source 15, such as a battery, which provides power to the entirety of the electrical elements of the capsule and transmitter 16 and antenna 17 for transmitting video

signals from imager 14. Signals may be transmitted using various digital or analog

modulation techniques. For example transmission of a digital image over a radio

channel may use an FSK (Frequency Shift Keying) modulation technique.

Externally to the body there is a receiver (not shown) for receiving the

signals transferred by transmitter 16 and antennal7.

Light rays from illumination sources 13 illuminate the GI tract inner wall.

Remitted light rays are collected by lenses 11 and 11' and directed by mirrors 18

and 18' to imager 14. Lens 11 gathers illumination rays at angle α, obtaining an

image field that is defined by angle α. Lens 11' gathers iUumination rays at angle

αl, obtaining an image field that is defined by angle αl. Thus, by using both lenses

11 and 11', an image field defined by angle (α + αl) can be covered.

Two more optical paths can be situated in parallel to the paths which

include lens 11 and mirror 18 and lens 11' and mirror 18' so that an image field

twice as wide can be covered. In this manner, a wide field in different planes can be

imaged, as further shown in Fig. IB.

Fig. IB is a schematic radial cross section illustration of a system

comprising four optical paths 11, 11', 11" and 11'" in all of which remitted light is

directed to a single imager 14. The four fields 101, 101', 101" and 101'" covered

by the four optical paths 11, 11', 11" and 11'" are imaged onto imager 14

coincidentally. As shown in Fig. 1C each of the fields 101, 101', 101" and 101'" takes up a quarter of the imager 14 face area (for example, 128X128 pixels of the

256X256 pixels area of the imager).

The optical schemes illustrated in Figs. 1A and IB provide a viewing angle

that is larger than 180°, in the longitudinal plane (Fig 1A) and 360° imaging in a

plane perpendicular to the longitudinal plane (Fig IB).

Similarly, the system of the invention may comprise five optical paths, as

shown in Fig. 2A. Fig. 2A schematically illustrates the system comprising an optical

path which includes lens 21 and mirror 28, an optical path which includes lens 21 '

and mirror 28' and an optical path which includes lens 25. Together with two more

optical paths that are situated in parallel to the paths that include lens 21 and mirror

28 and lens 21' and mirror 28', there are five optical paths covering a wide image

field.

Fig. 2B is a schematic radial cross section illustration of a system

comprising five optical paths (only four optical paths 21, 21', 21" and 21'" are

shown) in which remitted light is directed to a single imager 24. The five fields 201,

201', 201", 201"' and 205 covered by the five optical paths are imaged onto

imager 24 coincidentally.

The five optical path scheme shown in Figs. 2A and 2B provides optionally

better overlapping between margins of neighboring optical path fields than the four

optical path scheme and thus enables better reconstruction of a single combined

image. The system illustrated in Figs. 2 A and 2B can be incorporated in or attached

to device 20 which may be an endoscope, a needle, a stent, a capsule designed to

pass through the GI tract, etc.

The components of the system according to an embodiment of the invention

may be specifically designed for the system, or the system may utilized some

components from other systems that operate in body lumens, thus economically

talcing advantage of existing components. For example, the system of the invention

may be incorporated into or affixed onto medical devices meant for being inserted

into body lumens, such as needles, stents, endoscopes or capsules designed to pass

through the entire GI tract. For example, endoscopes utilize a light source and

sometimes an imaging device while operating. Thus, the system of the invention can

be incorporated into an endoscope and utilize the endoscope's light source and

imaging device.

Combining multiple images to a single image is schematically shown in

Fig. 3. The four different fields 301, 301', 301" and 301'" imaged on imager 34 are

combined into a single image 31 which is a wide angle image of the lumen being

viewed. The obtained images may be presented separately for a physician's

examination, or may be combined and presented as a single wide-angle image.

As shown in Figs. IB and 2B there can be an overlap between the fields

obtained by the different optical paths. Thus, part of the fields 301, 301', 301" and

301'" may be the same. For example, points Al, A2, A3 and A4 all represent the

same pixel, while point B represents a pixel unique to field 301'. The combination into the single image 31 may be performed, for example,

by applying an algorithm which assigns each image point (pixel) in the different

fields 301, 301', 301" and 301'" to another point (pixel) of the single image 31.

Thus, points Al, A2, A3 and A4 will be assigned to point A in image 31 and point

B will be assigned to point B 1 in image 31.

The four different fields 301, 301', 301" and 301'" may be combined by a

combiner in the receiving system which is adapted to combine a plurality of images

into a single image. The operation of combining images into a single image usually

requires significant processing effort and computing resources. Therefore this

operation is usually performed off-line (after receiving the image transmitted from

the imager) in an external recording/processing device (not shown).

Another embodiment of the invention is schematically illustrated in Fig. 4,

in which a longitudinal cross section of device 40 is schematically shown. Device

40 comprises two optical domes 42 and 402 behind which are situated illumination

sources 43 and 403 and optical paths 41 and 401, respectively. In optical paths 41

and 401 remitted light is directed to imagers 44 and 404 respectively. The device 40

further comprises power source 45, which provides power to the entirety of

electrical elements of the device, and transmitter 46 and antenna 47 for transmitting

video signals from the imagers 44 and 404. The system of the invention, as operable

in device 40, is capable of simultaneously obtaining images of the body lumen, for

example, the GI tract, from two ends of the device. For example, device 40 may be a

cylindrical capsule having a front end and a rear end, which is capable of passing the entire GI tract. The system in a cylindrical capsule can image the GI tract in the

front and in the rear of the capsule.

In one embodiment, device 40 is inserted into a body lumen, for example a

patient's GI tract. The patient may swallow the device and it will start its journey in

the patient's GI tract. Some parts of this journey are through voluminous areas of

the GI tract, for example, the stomach or the large intestine, in which the device 40

is not always oriented "head first", with one end of the device leading and the other

end following. In the wider areas of the GI tract the device 40 may tumble in a

rotating motion through the GI tract. In this case, simultaneous imaging of the front

and rear of the device 40 is advantageous in imaging a wide field of the lumen.

Also, there is an advantage in viewing the same site from different angles (as

imaged by the front imager e.g., 44 and by the rear imager e.g., 404), especially, for

example, if the site is enclosed in a fold of the GI tract.

Both images obtained by imagers 44 and 404 may be transmitted by

transmitter 46 serially or simultaneously, as described above. Optionally, each

imager may be assigned a separate transmitter and channel for transmitting the

images. The two images (front and rear) can be displayed separately or as a single

combined image.

In another embodiment of the invention a plurality of optical paths and a

plurality of imagers are employed. The system schematically illustrated in Fig. 5

comprises a plurality of optical paths, for example 52 and 52' having a plurality of

imagers, for example 54 and 54'. In each optical path 52 and 52', which may include lenses and mirrors for gathering and collimating remitted light, the remitted

light is directed to a separate imager 54 and 54' respectively, such that different

portions of the body lumen are imaged on different imagers. Optical paths 52 and

52' may be situated in capsule 50, which is designed to pass through and image the

entire GI tract.

The different images, which may be acquired simultaneously, can be

transferred to a receiving system over a single channel or over a multi channel link,

as described above.

In a single channel link the concurrently acquired images are transferred

serially and a multiplexer may be used to effect transmission. A single channel link

operates at a higher frequency than a multi channel link. In a multi channel link the

images can be transferred in parallel and at a lower frequency and thus have larger

bandwidths. The multi channel link may thus be more suitable for transferring larger

amounts of data. Also, the lower frequency multi channel link may be more suitable

for use with a capsule 50 designed to pass through and image the entire GI tract in

which the frequency used for transmitting images from the GI tract is usually

limited to the 200 - 500 MHz range.

Another embodiment of the invention is schematically illustrated in Figs. 6

and 7. In Fig. 6 a longitudinal cross section of device 60 is schematically illustrated.

Device 60 comprises a plurality of optical paths 62, 62' and 62" in which remitted

light is directed to imagers 64, 64' and 64" respectively. Each optical path and

respective imager are partitioned off from the other optical paths and imagers by partitions 601, 602 and 603, and each partitioned optical path has its own

illumination source 63, 63' and 63". In one embodiment the device 60 comprises an

optical dome which may extend over most of the device, covering the optical paths

62, 62' and 62", or the device may include an optical dome covering optical path

62' and optical windows on the sides of the device covering optical paths 62 and

62". Partitions 601, 602 and 603 may be made of opaque material and may serve to

prevent interference between the operation of the different imagers and their

associated illumination sources.

A radial cross section of a device comprising a plurality of optical paths

partitioned from each other is shown in Fig. 7. The device 70 may be cylindrical

shaped, similar to a swallowable capsule or to an endoscope tip, or it may a

transparent sphere shaped device or it may be of any shape suitable for being

inserted into and passing through a body lumen.

In device 70 each of the imagers 74 faces a portion of the body lumen at 90°

to its neighboring imager. The body lumen is illuminated by illumination sources 73

and remitted light is directed onto imager 74 through optical path 72. In this manner

a complete 360° field can be imaged. The mechanical dividers, partitions 701, serve

to avoid having interference between the different imagers 74 and illumination

sources 73.

It will be appreciated by persons skilled in the art that the present invention

is not limited by what has been particularly shown and described herein above.

Rather the scope of the invention is defined by the claims which follow.

Claims

1. A system for wide field imaging of body lumens comprising

at least one imager; and

an optical system having a plurality of optical paths for imaging

images from within the body lumen onto the at least one imager.

2. The system according to claim 1 and further comprising a memory

device for storing images.

3. The system according to claim 1 further comprising at least one

transmitter for transmitting signals from the imager.

4. The system according to claim 3 further comprising a receiving system

for receiving the signals.

5. The system according to claim 4 wherein the receiving system comprises

a recording and/or processing device.

6. The system according to claim 5 wherein the receiving system comprises

a combiner adapted to combine a plurality of images into a single image.

7. The system according to claim 1 comprising a single imager and a single

transmitter.

8. The system according to claim 1 comprising a plurality of imagers and a

single transmitter, said plurality of imagers each having a respective

optical path.

9. The system according to claim 3 wherein the transmitter transmits in a

single channel.

10. The system according to claim 3 wherein the transmitter transmits in

multiple channels.

11. The system according to claim 8 wherein the imagers and their

respective optical paths are partitioned off from each other.

12. A device for imaging a body lumen comprising a system which

comprises at least one imager and an optical system having a plurality of

optical paths for imaging images from within the body lumen onto the at

least one imager.

13. The device according to claim 12 further comprising an optical window.

14. The device according to claim 12 wherein the imager further comprises a

memory device for storing images.

15. The device according to claim 12 wherein the system further comprises

at least one transmitter for transmitting signals from the imager.

16. The device according to claim 15 wherein the system further comprises a

receiving system for receiving the signals from the transmitter.

17. The device according to claim 16 wherein the receiving system

comprises a recording/processing device.

18. The device according to claim 17 wherein the receiving system

comprises a combiner adapted to combine a plurality of images into a

single image.

19. The device according to claim 12 wherein the system comprises a single

imager and a single transmitter.

20. The device according to claim 12 wherein the system comprises a

plurality of imagers and a single transmitter, said plurality of imagers

each having a respective optical path.

21. The device according to claim 15 wherein the transmitter transmits in a

single channel.

22. The device according to claim 15 wherein the transmitter transmits in

multiple channels.

23. The device according to claim 20 wherein the imagers and their

respective optical paths are partitioned off from each other.

24. The device according to claim 12 wherein the device is configured for

being inserted into a body lumen.

25. The device according to claim 24 wherein the body lumen is the

gastrointestinal tract.

26. A capsule comprising an optical window and a system which comprises

at least one imager and an optical system having a plurality of optical

paths for imaging images from within the body lumen onto the at least

one imager.

27. The capsule according to claim 26 wherein the system is located behind

the optical window.

28. An endoscope comprising a system which comprises at least one imager

and an optical system having a plurality of optical paths for imaging

images from within the body lumen onto the at least one imager.

29. A method for wide field imaging of body lumens comprising the steps

of:

inserting into a body lumen a system comprising at least one imager

and an optical system having a plurality of optical paths for imaging

images from within the body lumen onto the at least one imager; and

obtaining a plurality of images from within the body lumen from the

plurality of optical paths.

30. The method according to claim 29 further comprising the step of

combining the plurality of images into a single image.

31. The method according to claim 29 further comprising the step of storing

the obtained images in a memory device for further analysis.

32. The method according to claim 29 further comprising the step of

transmitting signals from the imager.

33. The method according to claim 32 further comprising the step of

receiving the transmitted signals.

34. The method according to claim 32 wherein the signals are transmitted

over a single channel.

35. The method according to claim 32 wherein the signals are transmitted

over multiple channels.

36. The method according to claim 29 wherein inserting the system into a

body lumen is by swallowing.

37. A method for wide field imaginging of the gastrointestinal tract

comprising the steps of:

inserting into the gastrointestinal tract a device comprising a system

which comprises at least one imager and an optical system having a

plurality of optical paths for imaging images from within the body lumen

onto the at least one imager; and

obtaining a plurality of images from within the gastrointestinal tract

from the plurality of optical paths.

38. The method according to claim 37 wherein the step of inserting into the

gastrointestinal tract a device is achieved by swallowing the device.

39. A method for wide field imaging of the gastrointestinal tract comprising

the steps of:

inserting into the gastrointestinal tract an endoscope comprising a

system which comprises at least one imager and an optical system having

a plurality of optical paths for imaging images from within the body

lumen onto the at least one imager; and

obtaining a plurality of images from within the gastrointestinal tract

from the plurality of optical paths.

40. A transmitter for transmitting signals from within a body lumen, said

transmitter operable with a system comprising at least one imager and an

optical system having a plurality of optical paths for imaging images

from within the body lumen onto the at least one imager.

41. The transmitter according to claim 40 wherein the transmitting channel

is a radio channel.

42. The transmitter according to claim 40 wherein the signals are digital

signals.

43. The transmitter according to claim 40 wherein the signals are analog

signals.

44. The transmitter according to claim 40 having a single transmitting

channel.

45. The transmitter according to claim 44 further comprising a multiplexer.

46. The transmitter according to claim 40 having multiple transmitting

channels.

47. The transmitter according to claim 46 transmitting in the 200 - 500 MHz

range.

48. A receiving system for receiving signals from a transmitter transmitting

signals from within a body lumen, said receiving system operable with a

system comprising at least one imager and an optical system having a

plurality of optical paths for imaging images from within the body lumen

onto the at least one imager.

49. The receiving system according to claim 48 comprising a recording

and/or processing device.

50. The receiving system according to claim 48 further comprising a

combiner adapted for combining a plurality of images into a single

image.