 |
Claims  |
|
|
What is claimed is:
1. An image composing endoscope comprising:
i) a deep portion image output system comprising:
a) a first flexible fiber bundle having an entry end, from which light is entered into the fiber bundle, and a radiating end, from which the light having been entered into the fiber bundle is radiated out and which is inserted into the region
inside of a sample to be viewed,
b) a first light source for producing the light, which is to be entered into the first fiber bundle from the entry end, and
c) a deep portion image output means for irradiating the light, which has been radiated out of the radiating end of the first fiber bundle, to the region inside of the sample such that the light may reach portions deep from the inner surface of
the sample in the region inside of the sample, and thereby generating a deep portion image signal representing a deep portion image of the region inside of the sample,
ii) a surface image output system comprising:
a) a second flexible fiber bundle having an entry end, from which light is entered into the fiber bundle, and a radiating end, from which the light having been entered into the fiber bundle is radiated out and which is inserted into the region
inside of a sample to be viewed,
b) a second light source for producing the light, which is to be entered into the second fiber bundle from the entry end, and
c) a surface image output means for generating a surface image signal representing a surface image of the region inside of the sample, and
iii) an image composing and displaying means for composing an image from the deep portion image, which is represented by the deep portion image signal obtained from the deep portion image output system, and the surface image, which is represented
by the surface image signal obtained from the surface image output system, and displaying the composed image, wherein
the first light source of the deep portion image output system is a frequency-sweep single laser beam source capable of producing a laser beam to be entered into the first fiber bundle from the entry end, the frequency of the laser beam being
swept with the passage of time, and
the deep portion image output means of the deep portion image output system comprises:
1) a deep portion image signal forming means for splitting the laser beam into a first beam that is irradiated to the region inside of the sample and then reflected from reflection planes of the sample, and a second laser beam that follows a
predetermined optical path length, causing the first beam and the second beam to interfere with each other, and obtaining a plurality of different difference-frequency beat signals such that the frequencies, at which the intensities of the
difference-frequency beat signals repeatedly become high and low, may vary in accordance with the difference between depths of the reflection planes from the inner surface of the sample, and
2) a deep portion image signal output means for discriminating a difference-frequency beat signal, the intensity of which repeatedly becomes high and low at a predetermined frequency, from the plurality of different difference-frequency beat
signals, and generating a deep portion image signal, which represents the form and/or structure of a portion located at a specific depth from the inner surface of the sample, from the optical intensity of the discriminated difference-frequency beat
signal, the intensity of which repeatedly becomes high and low at the predetermined frequency, wherein
the first fiber bundle is constituted of single mode fibers,
the deep portion image signal forming means comprises:
1) an optical path splitting means for splitting the laser beam before being entered into the first fiber bundle from the entry end into two laser beams having planes of polarization, which planes of polarization are approximately normal to each
other,
2) a first wavefront matching means for matching the wave fronts of the two laser beams, which have been split by the optical path splitting means, with each other before the two split laser beams are entered into the first fiber bundle from the
entry end, a wavefront-matched laser beam being thereby obtained,
3) a second wavefront matching means for splitting the wavefront-matched laser beam, which has been radiated out of the radiating end of the first fiber bundle, into two laser beams having planes of polarization, which planes of polarization are
approximately normal to each other, such that one of the two split laser beams may travel by the predetermined optical path length, and such that the other laser beam may be irradiated to and reflected by the sample, the second wavefront matching means
thereafter matching the wave front of the laser beam, which has traveled by the predetermined optical path length, with the wave front of the laser beam, which has been irradiated to and reflected by the sample,
4) a polarization means for causing the components of the two laser beams subjected to the wavefront matching by the second wavefront matching means, which components have an identical direction of polarization, to interfere with each other and
5) a two-dimensional optical intensity detecting means for detecting the plurality of different difference-frequency beat signals obtained from the interference such that the frequencies, at which the intensities of the difference-frequency beat
signals repeatedly become high and low, may vary, and
the deep portion image signal output means comprises:
1) a frequency analyzing means for discriminating a difference-frequency beat signal, the intensity of which repeatedly becomes high and low at a predetermined frequency, from the plurality of different difference-frequency beat signals, and
2) a reconstruction means for generating an image signal, which represents the form and/or structure of a portion located at a specific depth from the inner surface of the sample, from the discriminated difference-frequency beat signal, the
intensity of which repeatedly becomes high and low at the predetermined frequency.
2. An image composing endoscope as defined in claim 1 wherein the second light source of the surface image output system is an RGB laser beam source,
the second fiber bundle of the surface image output system is constituted of single mode fibers, and
the surface image output means of the surface image output system comprises:
(1) a surface image detecting means for detecting an RGB laser beam, which has been radiated out of the radiating ends of the single mode fibers and which has then been reflected by the inner surface of the sample in the region inside of the
sample, and
(2) a surface image signal output means for generating a surface image signal representing a surface image of the region inside of the sample from the reflected laser beam, which has been detected by the surface image detecting means.
3. An image composing endoscope comprising:
i) a deep portion image output system comprising:
a) a first flexible fiber bundle having an entry end, from which light is entered into the fiber bundle, and a radiating end, from which the light having been entered into the fiber bundle is radiated out and which is inserted into the region
inside of a sample to be viewed,
b) a first light source for producing the light, which is to be entered into the first fiber bundle from the entry end, and
c) a deep portion image output means for irradiating the light, which has been radiated out of the radiating end of the first fiber bundle, to the region inside of the sample such that the light may reach portions deep from the inner surface of
the sample in the region inside of the sample, and thereby generating a deep portion image signal representing a deep portion image of the region inside of the sample,
ii) a surface image output system comprising:
a) a second flexible fiber bundle having an entry end, from which light is entered into the fiber bundle, and a radiating end, from which the light having been entered into the fiber bundle is radiated out and which is inserted into the region
inside of a sample to be viewed,
b) a second light source for producing the light, which is to be entered into the second fiber bundle from the entry end, and
c) a surface image output means for generating a surface image signal representing a surface image of the region inside of the sample, and
iii) an image composing and displaying means for composing an image from the deep portion image, which is represented by the deep portion image signal obtained from the deep portion image output system, and the surface image, which is represented
by the surface image signal obtained from the surface image output system, and displaying the composed image, wherein
the first light source of the deep portion image output system is a frequency-sweep laser beam source capable of producing at least two laser beams having different frequencies, which laser beams are to be sequentially entered into the first
fiber bundle from the entry end, the frequencies of the laser beams being swept with the passage of time, and
the deep portion image output means of the deep portion image output system comprises:
1) a deep portion image signal forming means for splitting each one of the laser beams into a first beam that is irradiated to the region inside of the sample and then reflected from reflection planes of the sample, and a second laser beam that
follows a predetermined optical path length, causing the first beam and the second beam to interfere with each other, and obtaining a plurality of different difference-frequency beat signals such that the frequencies, at which the intensities of the
difference-frequency beat signals repeatedly become high and low, may vary in accordance with the difference between depths of the reflection planes from the inner surface of the sample, and
2) a deep portion image signal output means for discriminating a difference-frequency beat signal, the intensity of which repeatedly becomes high and low at a predetermined frequency, from the plurality of different difference-frequency beat
signals, and calculating values concerning constituents and/or functions of a portion, which is located at a specific depth from the inner surface of the sample, from at least two discriminated difference-frequency beat signals, the intensities of which
repeatedly become high and low at predetermined frequencies and which are obtained when at least two laser beams having different frequencies and having been produced by the frequency-sweep laser beam source are respectively irradiated to the sample, the
deep portion image signal output means thereafter generating a deep portion image signal, which represents constituents and/or functions of the portion located at the specific depth from the inner surface of the sample, from the calculated values,
wherein
the first fiber bundle is constituted of single mode fibers, the deep portion image signal forming means comprises:
1) an optical path splitting means for splitting the laser beam before being entered into the first fiber bundle from the entry end into two laser beams having planes of polarization, which planes of polarization are approximately normal to each
other,
2) a first wavefront matching means for matching the wave fronts of the two laser beams, which have been split by the optical path splitting means, with each other before the two split laser beams are entered into the first fiber bundle from the
entry end, a wavefront-matched laser beam being thereby obtained,
3) a second wavefront matching means for splitting the wavefront-matched laser beam, which has been radiated out of the radiating end of the first fiber bundle, into two laser beams having planes of polarization, which planes of polarization are
approximately normal to each other, such that one of the two split laser beams may travel by the predetermined optical path length, and such that the other laser beam may be irradiated to and reflected by the sample, the second wavefront matching means
thereafter matching the wave front of the laser beam, which has traveled by the predetermined optical path length, with the wave front of the laser beam, which has been irradiated to and reflected by the sample,
4) a polarization means for causing the components of the two laser beams subjected to the wavefront matching by the second wavefront matching means, which components have an identical direction of polarization, to interfere with each other, and
5) a two-dimensional optical intensity detecting means for detecting the plurality of different difference-frequency beat signals obtained from the interference such that the frequencies, at which the intensities of the difference-frequency beat
signals repeatedly become high and low, may vary, and
the deep portion image signal output means comprises:
1) a frequency analyzing means for discriminating a difference-frequency beat signal, the intensity of which repeatedly becomes high and low at a predetermined frequency, from the plurality of different difference-frequency beat signals, and
2) a reconstruction means for calculating values concerning constituents and/or functions of a portion, which is located at a specific depth from the inner surface of the sample, from at least two discriminated difference-frequency beat signals,
the intensities of which repeatedly become high and low at predetermined frequencies and which are obtained when at least two laser beams having different frequencies and having been produced by the frequency-sweep laser beam source are respectively
irradiated to the sample, the reconstruction means thereafter generating a deep portion image signal, which represents constituents and/or functions of the portion located at the specific depth from the inner surface of the sample, from the calculated
values.
4. An image composing endoscope as defined in claim 3, wherein the second light source of the surface image output system is an RGB laser beam source,
the second fiber bundle of the surface image output system is constituted of single mode fibers, and
the surface image output means of the surface image output system comprises:
(1) a surface image detecting means for detecting an RGB laser beam, which has been radiated out of the radiating ends of the single mode fibers and which has then been reflected by the inner surface of the sample in the region inside of the
sample, and
(2) a surface image signal output means for generating a surface image signal representing a surface image of the region inside of the sample from the reflected laser beam, which has been detected by the surface image detecting means. |
|
 |
|
 |
Claims |
|
|
|
Description |
|
|
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an endoscope for primarily visualizing the inner surface of the body cavity of a living body. This invention particularly relates to an endoscope for visualizing the forms, structures, constituents and/or functions of
the inner surface of the body cavity and deep portions of the body cavity, which portions are deep from the inner surface of the body cavity. This invention also relates to an endoscope for obtaining an image composed from a visible image of the inner
surface of the body cavity and each of images representing the forms, structures, constituents and/or functions of the inner surface and deep portions of the body cavity.
2. Description of the Prior Art
As endoscopes for visualizing the regions inside of samples, i.e. inner surfaces of body cavities of living bodies, and the like, fiberscopes utilizing optical fibers have heretofore been used.
The fiberscope is provided with an illuminating light source and an image input means, which are located at one end of a flexible bundle of optical fibers. The fiberscope is also provided with an image output means, which is located at the other
end of the optical fiber bundle. The image output means feeds out an image, which has been fed into the image input means, via the optical fibers to the exterior. The one end side of the optical fiber bundle is inserted into the body cavity, and
illuminating light is produced by the illuminating light source and irradiated to the inner surface of the body cavity. An image formed by the light, which has been reflected by the inner surface of the body cavity, is fed into the image input means,
transmitted through the optical fibers extending to the region outside of the body cavity, and fed out from the image output means. In this manner, the inner surface of the body cavity is viewed in a real time fashion from the region outside of the body
cavity.
As described above, the fiberscope enables the real time viewing of the region inside of the body cavity. The fiberscope also enables examinations utilizing forceps channels and medical treatment utilizing electricity, microwaves, laser beams,
and the like.
Electron endoscopes utilizing the recently rapidly advanced electronic technology and image processing technology have also heretofore been used.
The electron endoscope is provided with a charge coupled device (CCD) in lieu of the image input means of the fiberscope. An image taken up by the endoscope is converted into an electric signal. The electric signal is transmitted through a
transmission medium and is fed out from an image output means. The image is then reconstructed by a video processor.
As described above, with the electron endoscope, an image taken up by the endoscope can be obtained as an electric signal. Therefore, the electron endoscope is advantageous for communication characteristics, such as image filing and transmission
characteristics, and image processing characteristics.
With the rapid advances made in medical treatment and diagnostic techniques utilizing endoscopes in recent years, there has arisen a strong demand for endoscopes capable of providing a wide variety of information.
For example, if information representing the form, the structure, constituents and/or functions of a portion under a mucous membrane at the surface of a digestive organ is obtained, a diseased part, which cannot be viewed from the surface of the
digestive organ, can be detected. Therefore, it becomes possible to detect and treat the disease in its early stages.
Also, investigating the relationship between the information, which represents constituents and/or functions, and the diseased part is very useful in clarifying the mechanisms of occurrence and progress of various diseases.
However, with the conventional endoscopes described above, only the visible surface image of the region inside of the body cavity, which image is formed with light reflected from the inner surface of the body cavity, can be viewed. With the
conventional endoscopes described above, information representing the forms, structures, constituents and/or functions of portions deep from the inner surface of the body cavity cannot be obtained.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a deep portion visualizing endoscope, which is capable of visualizing the forms and/or structures of the inner surface of the body cavity and deep portions of the body cavity, which
portions are deep from the inner surface of the body cavity.
Another object of the present invention is to provide a function diagnosing endoscope, which is capable of visualizing constituents and/or functions of the inner surface of the body cavity and deep portions of the body cavity, which portions are
deep from the inner surface of the body cavity.
The specific object of the present invention is to provide an image composing endoscope, which obtains and displays an image composed from a surface image representing the shape of the inner surface of the body cavity and each of deep portion
images representing the forms, structures, constituents and/or functions of not only the inner surface but also deep portions of the body cavity.
The present invention provides a first deep portion visualizing endoscope. Specifically, the present invention provides, in an endoscope comprising:
i) a flexible fiber bundle having an entry end, from which light is entered into the fiber bundle, and a radiating end, from which the light having been entered into the fiber bundle is radiated out and which is inserted into the region inside of
a sample to be viewed,
ii) a light source for producing the light, which is to be entered into the fiber bundle from the entry end, and
iii) an image forming means for irradiating the light, which has been radiated out of the radiating end of the fiber bundle, to the region inside of the sample, and thereby obtaining a two-dimensional image of the region inside of the sample,
a deep portion visualizing endoscope, wherein the light source is a frequency-sweep single frequency laser beam source, which produces a laser beam to be entered into the fiber bundle from the entry end, and
the image forming means comprises:
a) an image signal forming means for causing the laser beam, which has been irradiated to the region inside of the sample and which has then been reflected from reflection planes of the sample, and the laser beam, which has been split from the
laser beam before being reflected from the reflection planes of the sample and which has traveled by a predetermined optical path length, to interfere with each other, and thereby obtaining an image signal composed of a plurality of kinds of
difference-frequency beat signals such that the frequencies, at which the intensities of the difference-frequency beat signals repeatedly become high and low, may vary in accordance with the difference between depths of the reflection planes from the
inner surface of the sample, and
b) an image reproducing means for discriminating a difference-frequency beat signal, the intensity of which repeatedly becomes high and low at a predetermined frequency, from the image signal, and reproducing an image of a reflection plane, which
is located at a predetermined depth from the inner surface of the sample, from the discriminated difference-frequency beat signal.
The present invention also provides a second deep portion visualizing endoscope, wherein the first deep portion visualizing endoscope in accordance with the present invention is modified such that the image signal forming means comprises:
1) an optical path splitting means for splitting the laser beam before being entered into the fiber bundle from the entry end into two laser beams having planes of polarization, which planes of polarization are approximately normal to each other,
2) a first wavefront matching means for matching the wave fronts of the two laser beams, which have been split by the optical path splitting means, with each other before the two split laser beams are entered into the fiber bundle from the entry
end, a wavefront-matched laser beam being thereby obtained,
3) a second wavefront matching means for splitting the wavefront-matched laser beam, which has been radiated out of the radiating end of the fiber bundle, into two laser beams having planes of polarization, which planes of polarization are
approximately normal to each other, such that one of the two split laser beams may travel by the predetermined optical path length, and such that the other laser beam may be irradiated to and reflected by the sample, the second wavefront matching means
thereafter matching the wave front of the laser beam, which has traveled by the predetermined optical path length, with the wave front of the laser beam, which has been irradiated to and reflected by the sample,
4) a polarization means for causing the components of the two laser beams subjected to the wavefront matching by the second wavefront matching means, which components have an identical direction of polarization, to interfere with each other, and
5) a two-dimensional optical intensity detecting means for detecting a plurality of kinds of difference-frequency beat signals obtained from the interference such that the frequencies, at which the intensities of the difference-frequency beat
signals repeatedly become high and low, may vary, and
the image reproducing means comprises:
1) a frequency analyzing means for discriminating a difference-frequency beat signal, the intensity of which repeatedly becomes high and low at a predetermined frequency, from the plurality of kinds of the difference-frequency beat signals,
2) a reconstruction means for reconstructing an image of a portion, which is located at a specific depth from the inner surface of the sample, from the discriminated difference-frequency beat signal, the intensity of which repeatedly becomes high
and low at the predetermined frequency, and
3) an image output means, which outputs the image having been reconstructed by the reconstruction means.
The present invention further provides a third deep portion visualizing endoscope, wherein the second deep portion visualizing endoscope in accordance with the present invention is modified such that a rotation means is provided which rotates the
second wavefront matching means, the polarization means, and the two-dimensional optical intensity detecting means together around an axis, which is approximately parallel to the optical path of the laser beam having been radiated out of the radiating
end of the fiber bundle.
The present invention still further provides a fourth deep portion visualizing endoscope, wherein the first deep portion visualizing endoscope in accordance with the present invention is modified such that the fiber bundle is a single mode image
fiber bundle,
the image signal forming means comprises:
1) a scanning means for causing the laser beam, which has been produced by the frequency-sweep single frequency laser beam source, to impinge sequentially upon entry ends of a plurality of image fibers constituting the image fiber bundle,
2) a fiber interference system located in an optical path of each image fiber in order to split the laser beam having been entered into the image fiber from its entry end into a laser beam, which travels by the predetermined optical path length,
and a laser beam, which is radiated out of a radiating end of the image fiber, the fiber interference system thereafter causing the laser beam, which has traveled by the predetermined optical path length, and the laser beam, which has been reflected by
the sample after being radiated out of the image fiber and which has then entered into the image fiber from the radiating end, to interfere with each other, and
3) a two-dimensional optical intensity detecting means for detecting a plurality of kinds of difference-frequency beat signals obtained from the interference such that the frequencies, at which the intensities of the difference-frequency beat
signals repeatedly become high and low, may vary, and
the image reproducing means comprises:
1) a frequency analyzing means for discriminating a difference-frequency beat signal, the intensity of which repeatedly becomes high and low at a predetermined frequency, from the plurality of kinds of the difference-frequency beat signals,
2) a reconstruction means for reconstructing an image of a portion, which is located at a specific depth from the inner surface of the sample, from the discriminated difference-frequency beat signal, the intensity of which repeatedly becomes high
and low at the predetermined frequency, and
3) an image output means, which outputs the image having been reconstructed by the reconstruction means.
With the deep portion visualizing endoscopes in accordance with the present invention, the laser beam, the frequency of which is swept with the passage of time, is produced by the frequency-sweep single frequency laser beam source. The laser
beam is entered into the fiber bundle from its entry end and transmitted to its radiating end, which is inserted into the region inside of the sample. The laser beam is then radiated out of the radiating end of the fiber bundle and irradiated to the
region inside of the sample.
The laser beam, which has been produced by the laser beam source, is split into two laser beams before the laser beam is irradiated to the region inside of the sample, i.e. immediately after it has been produced by the laser beam source, during
its travel inside of the fiber bundle, or immediately after it has been radiated out of the fiber bundle. One of the two split laser beams is not irradiated to the region inside of the sample and is caused to travel by the predetermined optical path
length.
The laser beam, which has been radiated out of the radiating end of the fiber bundle and has been irradiated to the region inside of the sample, is reflected from a plurality of reflection planes, which are located at the inner surface of the
sample and at portions deep from the inner surface. A plurality of laser beams having been reflected from the plurality of the reflection planes, which are located at the inner surface of the sample and at portions deep from the inner surface, and the
laser beam, which has traveled by the predetermined optical path length, are caused to interfere with each other by the image forming means.
The optical path lengths, by which the laser beams having been reflected from the reflection planes located at the inner surface of the sample and at portions deep from the inner surface of the sample have traveled, vary in accordance with the
difference between the depths of the reflection planes from the inner surface of the sample. Specifically, the time required to reach the image forming means varies for different laser beams reflected from different depths with respect to the inner
surface of the sample.
In such cases, the frequency of the laser beam having been produced by the laser beam source is swept with the passage of time. Therefore, at the time at which one of the laser beams having been reflected from different reflection planes of the
sample arrives at the image forming means, the frequency of the laser beam having traveled by the predetermined optical path length is determined by the difference between the optical path lengths of the two laser beams and a function of the frequency
with respect to the frequency sweep time which has occurred.
As described above, the laser beam, which has arrived at the image forming means after traveling by the predetermined optical path length, and the laser beam, which has arrived at the image forming means after being reflected by one of different
reflection planes of the sample, vary in the frequency. Therefore, when these two laser beams are caused to interfere with each other by the image forming means, a difference-frequency beat signal occurs. The intensity of the difference-frequency beat
signal repeatedly becomes high and low at a frequency equal to the difference between the frequencies of the two laser beams.
In the manner described above, a plurality of kinds of difference-frequency beat signals occur such that the frequencies, at which the intensities of the difference-frequency beat signals repeatedly become high and low, may vary in accordance
with the difference between the depths of the reflection planes from the inner surface of the sample. The image reproducing means discriminates a difference-frequency beat signal, the intensity of which repeatedly becomes high and low at a predetermined
frequency, from the plurality of kinds of the difference-frequency beat signals occurring such that the frequencies, at which the intensities of the difference-frequency beat signals repeatedly become high and low, may vary. In this manner, a laser
beam, which has been reflected from a reflection plane located at a predetermined depth in the sample, can be sorted out. Also, from the intensity of the laser beam, which has been reflected from the reflection plane located at the predetermined depth
in the sample, information representing the light absorption at the reflection plane can be obtained. Therefore, with the image reproducing means, a two-dimensional plane image representing the information at the predetermined depth in the sample can be
obtained from the reflected laser beam.
As described above, with the deep portion visualizing endoscopes in accordance with the present invention, portions deep from the inner surface of the body cavity, which could not be viewed with the conventional endoscopes, can be visualized as
plane images or tomographic images representing information at specific depths. Therefore, the deep portion visualizing endoscopes in accordance with the present invention are advantageous in that, for example, diseased parts occurring at positions deep
from the inner surface of the body cavity can be detected in their early stages.
The present invention also provides a first function diagnosing endoscope. Specifically, the present invention also provides, in an endoscope comprising:
i) a flexible fiber bundle having an entry end, from which light is entered into the fiber bundle, and a radiating end, from which the light having been entered into the fiber bundle is radiated out and which is inserted into the region inside of
a sample to be viewed,
ii) a light source for producing the light, which is to be entered into the fiber bundle from the entry end, and
iii) an image forming means for irradiating the light, which has been radiated out of the radiating end of the fiber bundle, to the region inside of the sample, and thereby obtaining a two-dimensional image of the region inside of the sample,
a function diagnosing endoscope, wherein the light source is a frequency-sweep laser beam source capable of producing at least two laser beams having different frequencies, which laser beams are to be sequentially entered into the fiber bundle
from the entry end, the frequencies of the laser beams being swept with the passage of time, and
the image forming means comprises:
a) an image signal forming means for causing a laser beam, which has been irradiated to the region inside of the sample and which has then been reflected from reflection planes of the sample, and the laser beam, which has been split from the
laser beam before being reflected from the reflection planes of the sample and which has traveled by a predetermined optical path length, to interfere with each other, and thereby obtaining an image signal composed of a plurality of kinds of
difference-frequency beat signals such that the frequencies, at which the intensities of the difference-frequency beat signals repeatedly become high and low, may vary in accordance with the difference between depths of the reflection planes from the
inner surface of the sample, and
b) an image reproducing means for discriminating a difference-frequency beat signal, the intensity of which repeatedly becomes high and low at a predetermined frequency, from the image signal, and calculating values concerning constituents and/or
functions of a reflection plane, which is located at a predetermined depth from the inner surface of the sample, from at least two discriminated difference-frequency beat signals, the intensities of which repeatedly become high and low at predetermined
frequencies and which are obtained when at least two laser beams having different frequencies are respectively irradiated to the sample, the image reproducing means thereafter reproducing an image, which represents constituents and/or functions of the
sample, from the calculated values.
The present invention further provides a second function diagnosing endoscope, wherein the first function diagnosing endoscope in accordance with the present invention is modified such that the image signal forming means comprises:
1) an optical path splitting means for splitting the laser beam before being entered into the fiber bundle from the entry end into two laser beams having planes of polarization, which planes of polarization are approximately normal to each other,
2) a first wavefront matching means for matching the wave fronts of the two laser beams, which have been split by the optical path splitting means, with each other before the two split laser beams are entered into the fiber bundle from the entry
end, a wavefront-matched laser beam being thereby obtained,
3) a second wavefront matching means for splitting the wavefront-matched laser beam, which has been radiated out of the radiating end of the fiber bundle, into two laser beams having planes of polarization, which planes of polarization are
approximately normal to each other, such that one of the two split laser beams may travel by the predetermined optical path length, and such that the other laser beam may be irradiated to and reflected by the sample, the second wavefront matching means
thereafter matching the wave front of the laser beam, which has traveled by the predetermined optical path length, with the wave front of the laser beam, which has been irradiated to and reflected by the sample,
4) a polarization means for causing the components of the two laser beams subjected to the wavefront matching by the second wavefront matching means, which components have an identical direction of polarization, to interfere with each other, and
5) a two-dimensional optical intensity detecting means for detecting a plurality of kinds of difference-frequency beat signals obtained from the interference such that the frequencies, at which the intensities of the difference-frequency beat
signals repeatedly become high and low, may vary, and
the image reproducing means comprises:
1) a frequency analyzing means for discriminating a difference-frequency beat signal, the intensity of which repeatedly becomes high and low at a predetermined frequency, from the plurality of kinds of the difference-frequency beat signals,
2) a reconstruction means for calculating values concerning constituents and/or functions of a portion, which is located at a specific depth from the inner surface of the sample, from at least two discriminated difference-frequency beat signals,
the intensities of which repeatedly become high and low at predetermined frequencies and which are obtained when at least two laser beams having different frequencies are respectively irradiated to the sample, the reconstruction means thereafter
reconstructing an image, which represents constituents and/or functions of the portion located at the specific depth from the inner surface of the sample, from the calculated values, and
3) an image output means, which outputs the image having been reconstructed by the reconstruction means.
The present invention still further provides a third function diagnosing endoscope, wherein the second function diagnosing endoscope in accordance with the present invention is modified such that a rotation means is provided which rotates the
second wavefront matching means, the polarization means, and the two-dimensional optical intensity detecting means together around an axis, which is approximately parallel to the optical path of the laser beam having been radiated out of the radiating
end of the fiber bundle.
The present invention also provides a fourth function diagnosing endoscope, wherein the first function diagnosing endoscope in accordance with the present invention is modified such that the fiber bundle is a single mode image fiber bundle,
the image signal forming means comprises:
1) a scanning means for causing the laser beam, which has been produced by the frequency-sweep laser beam source, to impinge sequentially upon entry ends of a plurality of image fibers constituting the image fiber bundle,
2) a fiber interference system located in an optical path of each image fiber in order to split the laser beam having been entered into the image fiber from its entry end into a laser beam, which travels by the predetermined optical path length,
and a laser beam, which is radiated out of a radiating end of the image fiber, the fiber interference system thereafter causing the laser beam, which has traveled by the predetermined optical path length, and the laser beam, which has been reflected by
the sample after being radiated out of the image fiber and which has then entered into the image fiber from the radiating end, to interfere with each other, and
| | |
