JPH10108831A - Endoscope device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove the uneveness of a fluorescent image caused by the ununiformity of illuminance distribution of exciting light in an observing part of an endoscope device. SOLUTION: A fluorescent image of an observing part 52 is photographed by a photographing means (not shown) disposed in the tip part of a conduit 20a, and a fluorescent image signal S1 is inputted to a picture image processor 14 outside the living body through the conduit 20a. On the other hand, an X-ray CT device consisting of an X-ray CT device body 30 or the like measures a distance between the observing part 52 and an exciting light irradiating part in the tip part of the conduit 20a, the inclination and the shape of the observing part 52 and inputs the measured data D1 to a calculation device 16. The calculation device 16 analyses the distribution of the exciting light illuminance in the observing part 52 on the basis of distance data in measured data and irradiation property data (measured) in an exciting light irradiating part on the tip part of the conduit 20a to figure out illuminance distribution data D2. The picture image processor 14 corrects the strength of the fluorescent image signal S1 on the basis of the illuminance distribution data D2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope apparatus for observing the inside of a living body, and more particularly to image processing for performing correction in accordance with an illuminance distribution in an endoscope.

[0002]

2. Description of the Related Art Conventionally, an endoscope has been widely used for observing the inside of a living body or for treating while observing the inside of a living body. In order to observe the inside of a living body using this endoscope, light emitted from an illumination light source arranged outside the living body is usually transmitted through a light guide made of an optical fiber housed in a flexible introduction tube. To irradiate the observation section with the guide. The normal image capturing unit captures a normal image of the observation unit using the illumination light reflected by the observation unit, and displays the output of the imaging unit on an image display unit such as a CRT. Thus, the operator can diagnose the observation unit inside the living body with reference to the normal image displayed on the image display means.

On the other hand, conventionally, generally, PDD (Photodyn
Various studies have been made on photodynamic diagnosis called amic Diagnosis). The PDD means that a photosensitizer having a tumor affinity and emitting fluorescence when excited by light is previously absorbed in a tumor portion inside a living body, and the portion in the excitation wavelength region of the photosensitizer in the portion is excited. This is a technique for irradiating light to generate fluorescence, displaying an image based on the fluorescence, and diagnosing a tumor portion.

For example, Japanese Patent Publication No. 63-9664,
JP-136630 and JP-A-7-59783 disclose a fluorescent image diagnostic apparatus for performing this PDD. Basically, this kind of fluorescent image diagnostic apparatus detects the excitation light irradiating means that irradiates the observation part inside the living body with the excitation light in the excitation wavelength region of the photosensitizer, and detects the fluorescence emitted by the photosensitizer. It consists of a means for capturing a fluorescent image of the observation unit, and an image display means for receiving the output of the image capturing means and displaying the fluorescent image. Composed into an integrated form. Here, when the captured fluorescent image of the observation unit is displayed on the image display means, the infiltration range of the tumor is shown as a fluorescent image because the photosensitizer has tumor affinity. Therefore, the operator can refer to this display image to grasp the invasion range of the tumor and determine an appropriate resection range.

[0005] When performing a treatment operation using these endoscopes or fluorescence diagnostic devices (hereinafter referred to as "endoscope devices"), the medical device is inserted into a living body in order to identify the position of a tumor portion in an observation portion. There is also a demand to accurately grasp the position of the distal end of the endoscope in a living body. Usually, the position of the observation unit is specified based on the insertion length of the introduction tube of the endoscope apparatus, and requires the experience of the operator.

However, the body part has irregularities, the distance from the illumination light irradiation system or the excitation light irradiation system to the observation part is not uniform, and the angle of the body part with respect to the optical axis of the irradiation light is constant. Therefore, the illuminance of light at the observation unit is generally non-uniform. When the illuminance of the light is non-uniform, the intensity of the reflected light or the fluorescence changes according to the level of the illuminance of the light. Therefore, the normal image or the fluorescent image displayed on the image display means changes the state of the observation unit. It is not exactly represented, and the diagnosis of the tumor part in the observation part may be erroneous.

Therefore, in order to remove the unevenness of the normal image and the fluorescent image due to the non-uniformity of the illuminance distribution of light,
For example, Japanese Patent Application Laid-Open No. 62-247232, Japanese Patent Publication No. 3-587
As shown in No. 29, when a fluorescent image is captured, a reflected image due to the excitation light reflected by the observation unit is also captured, and the fluorescent image signal is divided by an image signal indicating the reflected image to standardize the fluorescent image signal. Further, as shown in Japanese Patent Application No. 8-109369 filed by the present applicant, near-infrared light having a wavelength of 650 nm or more is irradiated to an observation section inside a living body, and near-infrared light reflected by the observation section is detected and observed. A method has been proposed in which a near-infrared image of a part is captured and a fluorescence image signal is normalized for each pixel based on an image signal indicating the near-infrared image.

However, the wavelength range of the excitation light usually used in the fluorescence diagnostic apparatus is from the ultraviolet to the visible part (300 to
It is known that such excitation light is largely absorbed by a living body such as a human body (see Japanese Patent Application No. 8-109369). Therefore, when the excitation light is largely absorbed by the living body, the image signal indicating the reflected image reflects not only the illuminance distribution of the excitation light but also the distribution of the absorption. Therefore, even if the above-described normalization is performed using the image signal indicating the reflection image, it is impossible to accurately remove the unevenness of the fluorescent image due to the non-uniformity of the illuminance distribution of the excitation light. On the other hand, near-infrared light having a wavelength of 650 nm or more is excellent in that absorption in a living body is small, but the excitation light and the near-infrared light have different wavelengths so that the same optical system is used to irradiate the observation unit. In this case, there is a problem that the irradiation areas are different. Therefore, even if the above-described normalization is performed for each pixel based on an image signal indicating a near-infrared image, it is still impossible to accurately remove the unevenness of the fluorescent image due to the non-uniformity of the illuminance distribution of the excitation light. It is possible.

On the other hand, any of the above-mentioned methods is a method of normalizing a fluorescent image signal based on an image signal indicating an image reflected by the reflected light in the observation unit. Since a component due to the reflected light is included, even if the illuminance distribution of the excitation light in the observation unit is uniform, the standardized signal has a problem that the intensity becomes uneven. This is for the following reason.

Since fluorescence has no directivity, when standardizing a fluorescence image signal with an image signal representing a reflected image, it is necessary to use an image signal representing a reflected image due to reflected light having no directivity. The reflected light is the surface reflection light (specular reflection light) at the observation unit
And the diffuse reflection light excluding the regular reflection light, the reflection image of the observation unit is obtained as an image in which the component depending on the regular reflection light and the diffuse reflection light in the observation unit is superimposed. Generally,
The directivity of the diffusely reflected light has no directivity similarly to the fluorescence. Therefore, in order to accurately standardize the fluorescence image signal, it is necessary to perform the above-described normalization on an image signal indicating a reflection image of only a component dependent on diffuse reflection light from which a component due to regular reflection light has been removed.

As a method of removing the component due to the specular reflection light, for example, as disclosed in Japanese Patent Application Laid-Open No. 62-247232, a method of separating and detecting a component depending on the specular reflection light and the diffuse reflection light with a polarizing filter is known. Are known. However, since the intensity of the specularly reflected light depends on the angle at which the excitation light is incident on the observation unit, when the rotation angle of the polarizing filter is fixed, a component that depends on the specularly reflected light is obtained from the reflection image of the observation unit having irregularities. It is difficult to completely remove.

Further, the illumination light optical system also has a problem that the illumination light illuminance distribution becomes non-uniform due to unevenness of the observation portion inside the living body. Therefore, since the intensity of the reflected light at the observation unit changes according to the level of the illuminance of the illumination light, the normal image displayed on the image display means has uneven brightness and hue. The reflected light of the illumination light at the observation unit inside the living body is composed of the specular reflection light at the observation unit and the diffuse reflection light excluding the specular reflection light. It is also necessary to remove components that depend on.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and eliminates unevenness of an image signal due to non-uniformity of the illuminance distribution of illumination light or excitation light in an observation section inside a living body. It is also possible to provide an endoscope apparatus capable of observing the state of the observation unit inside the living body with high accuracy, as well as removing a regular reflection image caused by the regular reflection light of the observation unit. Aim. Another object of the present invention is to provide an endoscope apparatus that facilitates identification of the position of an observation unit inside a living body.

[0014]

An endoscope apparatus according to the present invention has a distal end inserted into a living body, introduces light from a light source disposed outside the living body into the living body, and provides an observation section inside the living body. An imaging tube for imaging the observation unit and outputting an image signal indicating the observation unit; and a relative position between the observation unit and the emission unit of the light emitted from the introduction tube. Measuring means for determining the relationship; analyzing a pseudo component included in the image signal based on an output of the measuring means and a previously measured characteristic of irradiation light emitted from the emission unit; And image processing means for correcting so as to remove the image.

Here, "a pseudo component included in an image signal"
Is a component of an image signal generated due to the light in accordance with a relative positional relationship between the observation unit and an emission unit of the light emitted from the introduction tube, and is originally an image signal. It is an unnecessary component that must not be exposed.

The image signal may be an image signal indicating a normal image of the observation unit irradiated with the illumination light emitted from the light source, or the image signal may be transmitted to the observation unit absorbing a fluorescent substance which emits fluorescence. On the other hand, an image showing a fluorescence image of the observation part obtained by irradiating the excitation light emitted from the light source in the excitation wavelength region of the photosensitive substance and detecting the fluorescence emitted from the observation part at that time. Preferably, it is a signal. At this time, the image signal is not limited to either one, and may be both an image signal indicating a normal image and an image signal indicating a fluorescent image.

Further, the pseudo component includes a specular reflection image of the observation unit and / or a specular reflection image of the light resulting from the specular reflection light of the observation unit.
Or it is desirable that the image signal is uneven due to the illuminance distribution of the observation unit of the light, more specifically,
It is desirable that the unevenness of the image signal is unevenness of the intensity and / or color tone of the image signal.

The measuring means may include a computer tomography apparatus, a shape of the observation section obtained by the computer tomography apparatus, and a position of the observation section of the emission section of the light emitted from the introduction tube. It is preferable that the information processing apparatus includes an arithmetic unit that calculates a relative positional relationship between the observation unit and an emission unit of the light emitted from the introduction tube based on data.

[0019]

According to the endoscope apparatus of the present invention having the above-described structure, the relative position between the exit section of light emitted from the introduction tube of the endoscope apparatus to the observation section inside the living body and the observation section is determined. Since a positional relationship, for example, a distance or a tilt, can be obtained by the measuring unit, the image signal indicating the observation unit is output based on the output of the measuring unit and the previously measured characteristics of the irradiation light emitted from the emission unit. The included pseudo component is analyzed, and the pseudo component can be removed from the image signal by the image processing means. Therefore, the corrected image signal obtained by the image processing means does not include an unnecessary component as an image signal indicating the observation section inside the living body.

For example, when the image signal is an image signal indicating a normal image of the observation section, unevenness in luminance and hue due to non-uniformity of the illuminance distribution of the illumination light can be removed. The unevenness in luminance due to the above can also be removed.

Further, when the image signal is an image signal indicating a fluorescent image of the observation section, it is possible to remove unevenness in fluorescent intensity due to non-uniformity of the illuminance distribution of the excitation light.

Further, since the distance between the irradiation unit and the observation unit is objectively measured, it is easy to specify the position of the observation unit.

Therefore, when the endoscope apparatus according to the present invention is used in a medical field, the position of the observation section inside the living body is specified, and the normal image and the fluorescence image of the observation section are displayed on the image display device as good images. Therefore, the accuracy of diagnosis can be improved. Also, the operator can grasp the invasion range of the tumor with reference to the displayed image and determine an appropriate resection range.

On the other hand, in the present invention, the measuring means can be arranged outside the living body. In this case, X-ray CT, ultrasonic diagnostic equipment, MRI (magnetic resonance imaging) equipment, P
ET (positron emission tomography), S
Various computer tomography apparatuses (hereinafter, referred to as “CT apparatuses”) such as PECT (single photon emission computer tomography) can be used. By using a CT device, it is possible to accurately measure the relative positional relationship between the emission part of the light emitted to the observation part inside the living body and this observation part, and also to measure the inside of the living body of the inserted endoscope. Since the position can be accurately grasped, the position of the observation unit can be specified without depending on the insertion length of the introduction tube. Further, since the image of the endoscope apparatus and the image of the CT apparatus can be simultaneously displayed on the image display apparatus, the accuracy of diagnosis can be further improved by comparing and examining the two images.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an endoscope apparatus according to the present invention. The endoscope apparatus includes an endoscope 20, an X-ray CT apparatus including an X-ray CT apparatus main body 30, an X-ray source 32, and an X-ray detector 34 provided outside a living body, and a light source for excitation light. It comprises a control device 10, which is composed of an image processing device 14, an arithmetic device 16, and is arranged outside the living body, and image display devices 40, 42 for displaying image signals.

The endoscope 20 has a flexible introduction tube 20a, and the distal end of the introduction tube 20a is inserted into the living body 50 to the vicinity of the observation section 52. The excitation light L1 is emitted from the excitation light source 12 constituting the control device 10, guided to the endoscope 20 via the light guide 13, and further transmitted through the light guide (not shown) accommodated in the introduction tube 20a. Introductory pipe 20
The light is guided to the excitation light irradiation unit at the tip of “a”, and irradiates the observation unit 52. At the distal end portion of the introduction tube 20a, a fluorescence image capturing means (not shown) for detecting a fluorescence emitted from the observation unit 52 by being irradiated with the excitation light L1 and capturing a fluorescence image is provided. The fluorescent image capturing means outputs a fluorescent image signal S1 indicating a fluorescent image. The fluorescent image signal S1 is guided out of the living body through the introduction tube 20a, and constitutes the control device 10.
Entered into 14.

On the other hand, the X-ray CT apparatus main body 30 is so arranged that the X-ray source 32 and the X-ray detector 34 can perform tomographic observation of the observation section 52 inside the living body 50 and the excitation light irradiation section at the tip of the introduction tube 20a. Are arranged facing each other around the living body 50 so as to be movable based on a control signal S6. The X-ray detector 34 detects a component of the X-rays emitted from the X-ray source 32 that has passed through the living body 50. The output S5 of the X-ray detector 34 is an X-ray C
It is input to the T device main body 30. X-ray CT system body 30
Is an arithmetic unit 16 that constitutes the control device 10
At the same time, a CT image video signal S7 indicating a tomographic image of the observation section 52 inside the living body 50 and the excitation light irradiation section at the distal end of the introduction tube 20a is output to the CT image display device 42.

The arithmetic unit 16 outputs the illuminance distribution data D2 as a calculation result to the image processing unit 14, and outputs the illuminance distribution data D2 to the image processing unit 14.
Converts the intensity-corrected fluorescent image video signal S3 into an image display device.
Output to 40.

The irradiation characteristic data D3 of the excitation light L1 in the excitation light irradiation section at the tip of the introduction tube 20a is measured in advance and stored in a storage element (not shown) constituting the arithmetic unit 16. .

Hereinafter, the operation of the endoscope apparatus having the above configuration will be described. In the observation section 52 inside the living body 50, a photosensitizer having a tumor affinity and emitting fluorescence when excited by light is previously absorbed. As the photosensitizer, for example, a porphyrin-based photosensitizer is used.

Excitation light L1 emitted from the excitation light source 12 constituting the control device 10 arranged outside the living body is guided to the endoscope 20 via the light guide 13, and further stored in the introduction tube 20a. Introducing tube 20a via light guide (not shown)
The light is guided to the excitation light irradiating section at the tip of, and is irradiated to the observation section 52. When the observation section 52 is irradiated with the excitation light L1, fluorescence is emitted from the photosensitizer, and the fluorescence causes the introduction tube 20a to emit light.
The fluorescent image capturing means (not shown) provided at the tip of the camera captures a fluorescent image of the observation unit 52 and outputs a fluorescent image signal S1 indicating the fluorescent image of the observation unit 52. The fluorescent image signal S1 is guided out of the living body through the introduction tube 20a and is input to the image processing device 14 constituting the control device 10.

On the other hand, the main body 30 of the X-ray CT
While the X-ray source 32 and the X-ray detector 34 are moved little by little by 6 and the X-ray source 32 irradiates the living body 50 with X-rays, the X-rays transmitted through the living body 50 are detected by the X-ray detector 34. Thus, a tomographic image (CT image) of the excitation light irradiating unit at the distal end of the observation unit 52 and the introduction tube 20a inside the living body 50 is captured. By using such an X-ray CT apparatus, a plurality of CT images are taken so as to slice the living body 50, and the observation section 52 inside the living body 50 and the excitation light irradiating section at the distal end of the introduction tube 20a are three-dimensionally formed. Can be observed. Therefore, each C
From the T image and the moving distance of the X-ray source 32 and the X-ray detector 34, the distance and inclination between the observation unit 52 inside the living body 50 and the excitation light irradiation unit at the distal end of the introduction tube 20a are calculated, and the observation unit 52
Can be measured. This arithmetic processing is usually X
It can be performed by a computer constituting a part of the X-ray CT apparatus main body 30. Further, it can also be performed by the arithmetic unit 16 described later. In this case, a signal indicating the CT image and data indicating the moving distance of the X-ray source 32 and the X-ray detector 34 may be input to the arithmetic unit 16.

The measurement data D1 of the distance and inclination between the observation section 52 inside the living body 50 and the excitation light irradiation section at the distal end of the introduction tube 20a, and the measurement data D1 of the shape of the observation section 52 obtained by the X-ray CT apparatus are calculated by the arithmetic unit 16 Is input to The arithmetic unit 16 calculates the measurement data D1
Based on the medium distance data and the irradiation characteristic data D3 of the excitation light L1 in the excitation light irradiation unit at the distal end of the introduction tube 20a, the excitation light illuminance distribution in the observation unit 52 is analyzed as follows, and the illuminance distribution data D2 is obtained. calculate. The irradiation characteristic data D3 of the excitation light L1 is measured in advance, and the observation unit
If 52 is flat, the irradiation characteristic data D3 of the excitation light L1 is directly given as the excitation light illuminance distribution of the observation unit 52. However, in general, the observation section 52 is not flat but has irregularities. In this case, it is known that the excitation light density of the excitation light applied to the observation unit 52 is inversely proportional to the square of the distance, and the distance between the observation unit 52 and the excitation light irradiation unit at the distal end of the introduction tube 20a is known. The excitation light illuminance distribution of the observation unit 52 can be calculated by calculation from the data D1 and the irradiation characteristic data D3 of the excitation light L1. Therefore, the illuminance distribution data D2 in the observation unit 52 can be obtained accurately. It is well known that a fluorescent image is almost proportional to the intensity of excitation light. The image processing device 14 performs intensity correction on the fluorescent image video signal S1 based on the illuminance distribution data D2, and performs the intensity-corrected fluorescent image video signal S1.
3 is input to the image display device 40. Thereby, the observation unit 52
The unevenness of the fluorescence intensity due to the non-uniformity of the illuminance distribution of the excitation light in the above is removed, and a high-accuracy fluorescence image can be displayed on the image display device 40. Further, the CT image of the observation unit 52 obtained by the X-ray CT apparatus is input from the X-ray CT apparatus main body 30 as the CT image video signal S7 to the CT image display apparatus 42 and displayed at the same time. C
The T image and the fluorescent image can be compared, and more accurate diagnosis can be performed. Therefore, the accuracy of diagnosis can be improved by using this endoscope apparatus for diagnosis and treatment of a tumor inside a living body, and the operator can grasp the invasion range of the tumor by referring to these display images. , An appropriate resection range can be determined and resection can be performed.

The endoscope apparatus according to the present invention is not limited to the configuration of the above-described embodiment, but can be variously modified within the scope of the present invention. For example, when capturing a normal image with illumination light, unevenness in luminance and hue of the normal image due to non-uniformity of the illuminance distribution of the illumination light in the observation unit 52 can be removed by the same method as described above. .

Further, it is also possible to analyze the components of the specular reflection image of the illumination light by the specular reflection light in the observation unit 52 as follows, and remove the specular reflection image included in the normal image. The specularly reflected light is light that is reflected from the surface of the observation unit 52 at an angle equal to the angle at which the illumination light enters the observation unit 52. Therefore, the angle at which the illumination light enters the observation unit 52 can be calculated from the inclination and shape data in the distance, inclination, and shape measurement data D1, and the reflection angle of the specularly reflected light can also be calculated. on the other hand,
Since the intensity of the specularly reflected light is proportional to the intensity of the illumination light, the arithmetic unit 16 accurately calculates the illuminance distribution of the illumination light in the observation unit 52 as described above, and based on the reflection angle of the specularly reflected light. The reflected image can be accurately analyzed. Image processing device 14
Can accurately remove the components of the regular reflection image included in the normal image based on the analysis result. As a result, the unevenness of the brightness of the normal image caused by the specular reflection light of the illumination light in the observation unit 52 is removed, and the accurate normal image can be displayed on the image display device 40.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an endoscope apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 10 Control device 12 Light source for excitation light 13 Light guide 14 Image processing device 16 Processing device 20 Endoscope 20a Introductory tube 30 X-ray CT device main body 32 X-ray source 34 X-ray detector 40 Image display device 42 CT image display device 50 Living body 52 Observation part L1 Excitation light D1 Measurement data of distance, inclination and shape D2 Illuminance distribution data S1 Fluorescence image image signal S3 Fluorescence image image signal with intensity correction S5 X-ray detection signal S6 Control signal S7 CT image image signal

Claims (6)

[Claims] 1. An introduction tube having a tip inserted into a living body, for introducing light from a light source arranged outside the living body into the living body, and irradiating an observation section inside the living body, and an imaging section for imaging the observation section. An imaging unit that outputs an image signal indicating an observation unit; a measurement unit that determines a relative positional relationship between the observation unit and an emission unit of the light that is emitted from the introduction tube; an output of the measurement unit and measurement in advance Image processing means for analyzing a pseudo component included in the image signal based on the characteristics of the irradiated light emitted from the output unit, and correcting the image signal so as to remove the pseudo component from the image signal. An endoscope device characterized by the above-mentioned. 2. The endoscope apparatus according to claim 1, wherein the image signal is an image signal indicating a normal image of the observation unit irradiated with illumination light emitted from the light source. 3. The image signal irradiates an excitation light emitted from the light source in an excitation wavelength region of the photosensitive substance to the observation unit absorbing a photosensitive substance emitting fluorescence. 2. The endoscope apparatus according to claim 1, wherein the endoscope apparatus is an image signal indicating a fluorescence image of the observation unit obtained by detecting fluorescence emitted from the observation unit at that time. 4. The pseudo component is a specular reflection image of the observation unit due to the specular reflection light of the observation unit of the light and / or the unevenness of the image signal caused by the illuminance distribution of the observation unit of the light. The endoscope apparatus according to any one of claims 1 to 3, wherein: 5. The endoscope apparatus according to claim 4, wherein the unevenness of the image signal is unevenness of intensity and / or color tone of the image signal. 6. The computer tomography apparatus according to claim 6, wherein the measurement unit is a computer tomography apparatus, and the data of a shape of the observation unit obtained from the computer tomography apparatus and a position of the observation unit of an emission unit of the light emitted from the introduction tube. The endoscope apparatus according to any one of claims 1 to 5, further comprising: a calculation unit that calculates the relative positional relationship based on the relationship.