JP2003126015A - Endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endoscope which allows acquisition of images distinguishable between normal tissues and diseased tissues with a simple structure. SOLUTION: A light source device 3A has a filter switching part 14 which can be switched to an RGB filter for normal observation and to a filter for fluorescent observation in front of a lamp 12. Excitation light of wave band of a part of the blue wave band is supplied to the electronic endoscope 2A in case that a fluorescent image mode is selected. The excitation light reflected on the side of a subject is blocked by a filter 27 for cutting excitation light in front of a CCD 28, thus a fluorescent image is obtained. Distributing signals of the fluorescent image and of two reflective light images set in a specific wave band to R, G, B channels appropriately allows a display in hues to distinguish between normal tissues and diseased tissues easily.

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 diagnosing normal tissue and diseased tissue by obtaining a reflection image and a fluorescence image.

[0002]

2. Description of the Related Art In recent years, endoscopes have been widely used in medical fields and industrial fields. In particular, in the medical field, in addition to an endoscope apparatus that obtains a normal image using normal white light, a technique for obtaining an image that makes it easy to distinguish between normal tissue and diseased tissue has been proposed. .

For example, as a first conventional example, Japanese Patent Publication No. 5-
Japanese Patent No. 37650 discloses an apparatus for detecting an abnormal part of respiratory metabolism of a living body using a fluorescence image and a reference image by reference light. In addition, as a second conventional example, Japanese Patent Laid-Open No. H10-10
JP-A-309282 discloses an apparatus that irradiates excitation light and obtains an image in which normal tissue and diseased tissue are easily discriminated from two fluorescence images having different wavelength bands and a reflection image due to the excitation light. . In addition, as a third conventional example, Japanese Unexamined Patent Application Publication No.
Japanese Patent Publication No. 000-270265 discloses an apparatus for superposing a fluorescence image and a background image.

[0004]

In the first prior art, the regression line for the target tissue is derived using the fluorescence image and the reference image, but the wavelength of the reference image is made to match the wavelength of the fluorescence image. However, the discriminating function between normal tissue and diseased tissue may not be sufficient.

Further, the second conventional example has a complicated structure. Further, in the third conventional example, since the reflected light has a wide band, there is a drawback that the function of obtaining an image that makes it easy to distinguish between normal tissue and diseased tissue is deteriorated.

(Object of the Invention) The present invention has been made in view of the above-mentioned points, and an endoscope capable of obtaining an image in which a normal tissue and a diseased tissue can be easily distinguished with a simple structure. The purpose is to provide a device.

[0007]

A light source for generating excitation light for exciting illumination light and fluorescence of two different wavelength bands, a light guide means for guiding the illumination light and the excitation light, and the light guide. The living tissue is irradiated with the illuminating light through the means, and two reflected light images each of which is the reflected light reflected by the living tissue, an imaging unit that captures a fluorescence image of the fluorescence excited by the excitation light, and the two reflections. In an endoscopic device including an image processing means for processing a light image and a fluorescence image to construct a processed image, and a display means for displaying the processed image, two different reflected light intensity and fluorescent light intensity from a living tissue are measured. When plotted on the three-axis spatial coordinate axis, the reflected light and the fluorescence wavelength are selected so that the normal tissue and the diseased tissue are separated on the three-axis spatial coordinate axis, and the processed image processed by the processing means is Normal tissue and disease The normal tissue and the diseased tissue are distinguished by assigning and processing the reflected light and fluorescence to a specific color signal so that the tissues have different hues and the diseased tissue falls within a specific hue. An image that can be easily displayed is displayed in pseudo color.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 to 11 show a first embodiment of the present invention.
1 shows the entire configuration of the endoscope apparatus of the first embodiment, and FIG. 2 shows the configuration of a switching filter provided with a normal observation filter and a fluorescence observation filter. FIG. 3 shows the transmission characteristics of the normal observation filter, the fluorescence observation filter and the excitation light cut filter with respect to the wavelength, and FIG. 4 shows the characteristic example of the intensity distribution with respect to the wavelength of the fluorescence obtained from the biological tissue and the reflection obtained from the biological tissue. FIG. 5 shows an example of a characteristic of intensity distribution with respect to the wavelength of light, and FIG. 5 shows a state in which a normal portion and a lesion portion are distributed on the axial space coordinates with fluorescence intensity and two reflected light intensities as three axes, FIG. 6 shows the first
Shows the change in the resolution with respect to the central wavelength of the second reflected light when the wavelength of the reflected light of is used as a parameter,
FIG. 7 shows how the separation power changes with respect to the center wavelength of the second reflected light when the wavelength width of the first reflected light is used as a parameter, and FIGS. 8 and 9 show the fluorescence image in the G channel and the first in the first image. 10 and 1 are chromaticity diagrams showing distributions of a normal portion and a lesion portion obtained when the images of the second reflected light are set to the B and R channels and the R and B channels.
1 is a chromaticity diagram showing the distribution of the normal portion and the lesion portion obtained when the fluorescence image is set to the B channel and the images of the first and second reflected light are set to the G and R channels and the R and G channels. Show.

An endoscope apparatus 1 having a normal observation mode and a fluorescence observation mode according to the first embodiment of the present invention shown in FIG.
A is an electronic endoscope 2A for insertion into a body cavity for observation
And a light source device 3 that emits light for normal observation and light for excitation
A, a processor 4A that performs signal processing for constructing a normal observation image and a fluorescence image, and a monitor 5 that displays an image by normal light and an image by fluorescence.

The electronic endoscope 2A has an elongated insertion portion 7 to be inserted into a body cavity, and a distal end portion 8 of the insertion portion 7 has illumination means and imaging means built therein. A light guide fiber 9 that transmits (guides) illumination light and excitation light for normal observation is inserted into the insertion portion 7, and this light guide fiber 9
The light source connector 10 provided at the light-incident end on the near side is detachably connected to the light source device 3A.

The light source device 3A is driven by a lamp drive circuit 11 so as to emit light, and a lamp 12 which emits light including an infrared wavelength band to a visible light band, and is provided on an illumination optical path by the lamp 12, A light source diaphragm 13 that limits the amount of light from the light source 12, a switching filter unit 14 provided on the illumination optical path, and a condenser lens 15 that condenses the light that has passed through the switching filter unit 14 are provided.

This switching filter unit 14 is used for the rotary motor 1.
6 is rotated by a rotation motor 6, and a switching filter 17 that switches a filter arranged on the optical path by a movement motor 20 and a pinion 19 that is screwed into a rack 18 attached to the rotation motor 16 are driven to rotate. And a moving motor 20 for moving the switching filter 17 in the direction perpendicular to the optical axis together with the driving motor 16.

As shown in FIG. 2, the switching filter 17 is provided with an RGB filter 21 for normal observation and a filter 22 for fluorescence observation which are concentrically provided on the inner peripheral side and the outer peripheral side. By driving, the normal illumination filter 21 is set on the optical path to set the operating state in the normal image mode (also referred to as the normal mode), or the normal illumination filter 21 is switched to the fluorescent illumination filter 22 to switch the fluorescent image. It is possible to switch to the operating state set to the mode (also called the fluorescence mode).

The RGB filter 21 has R in the circumferential direction.
R, G, B filters 21a, 21b, 21c that respectively transmit light in the respective wavelength bands of (red), G (green), and B (blue).
Are divided into three equal parts, and each is sequentially driven in the optical path by being driven to rotate by the rotary motor 16, and substantially continuously.

Further, the R, G, B filters 21a, 21
The transmission characteristics of b and 21c are 60% as shown in FIG.
0-700nm, 500-600nm, 400-500
It has a filter characteristic of transmitting light of each wavelength band of nm. In FIG. 3 and the like, instead of the reference numerals 21a, 21b and 21c, reference numerals R, G and B corresponding to the filter transmission characteristics are provided.
Is used to indicate (the fluorescence observation filter 22 described later).
The same is true in).

Further, the fluorescence observation filter 22 includes R1, G1, and E1 filters 2 which respectively transmit narrow band red (R1), narrow band green (G1), and narrow band excitation light in the circumferential direction.
2a, 22b, 22c are provided so as to be divided into three equal parts,
Each of them is sequentially inserted into the optical path by being rotationally driven by the rotation motor 16. The transmission characteristics of the R1, G1, and E1 filters 22a, 22b, and 22c are shown in FIG.
As shown in 590-610 nm, 540-560n
m, 390-445 nm has a filter characteristic of transmitting light of each wavelength band.

Illumination light from the light source device 3A is transmitted (guided) to the tip side of the insertion portion 7 of the electronic endoscope 2A by the light guide fiber 9. The light guide fiber 9 transmits the light for fluorescence observation and the light for normal observation with a small transmission loss. The light guide fiber 9 is composed of, for example, a multi-component glass fiber, a quartz fiber or the like.

The light transmitted to the front end surface of the light guide fiber 9 is diverged through the illumination lens 24 attached to the illumination window facing the front end surface, and is radiated toward the observation target site side in the body cavity.

An observation window is provided at the tip portion 8 adjacent to the illumination window, and an objective lens system 25 for forming an optical image and a space for focusing from a far point to a near point are provided in the observation window. A diaphragm 26 that restricts the amount of incident light, an excitation light cut filter 27 that cuts excitation light, and a charge-coupled device that performs, for example, monochrome imaging (or monochrome imaging) as an imaging device that captures each image of fluorescence and reflected light ( CCD
28) are arranged. As an image pickup device for picking up fluorescence and reflection images, C is used instead of CCD 28.
MD (Charged Modulation Device) image sensor, CM
OS image sensor, AMI (Amplified MOS Imager), BCC
D (Back Illuminated CCD) may be used.

The excitation light cut filter 27 is a filter that shields the excitation light excited to generate fluorescence during fluorescence observation. The characteristic of the excitation light cut filter 27 is shown in FIG. 4 as shown in FIG.
It has a characteristic of transmitting a wavelength band of 70 to 700 nm, that is, transmitting visible light excluding a part of the wavelength (400 to 470 nm) of the blue band.

The electronic endoscope 2A is provided with a scope switch 29 for performing an instruction operation for selecting the fluorescence image mode and the normal image mode, and an instruction operation for freeze and release. It is input to the control circuit 37, and the control circuit 37 performs a control operation corresponding to the operation signal.

For example, when the normal mode switch of the mode changeover switch in the scope switch 29 is operated, the light source device 3A becomes a state in which the normal mode illumination light, that is, the lights of R, G, B are sequentially supplied to the light guide fiber 9, and The processor 4A is also in a state of performing signal processing corresponding to the normal mode.

When the fluorescence mode switch of the mode changeover switch is operated, the light source device 3A causes the light guide fiber 9 to illuminate in the fluorescence mode, that is, R1, G1, and E1.
The light is sequentially supplied, and the processor 4A is also in a state of performing signal processing corresponding to the fluorescence mode.

The CCD 28 is a C provided in the processor 4A.
It is driven by the CCD drive signal from the CD drive circuit 31 and photoelectrically converts the optical image formed on the CCD 28 to output an image signal.

This image signal is amplified by a preamplifier 32 provided in the processor 4A, further amplified by an automatic gain control (AGC) circuit 33 to a predetermined level, and then converted from an analog signal to a digital signal (by an A / D conversion circuit 34). Image data), and each image data is temporarily stored (stored) in the first frame memory 36a, the second frame memory 36b, and the third frame memory 36c via the multiplexer 35 for switching.

The CCD drive circuit 31 is a control circuit 37.
Controlled by. Specifically, as will be described later, in the normal mode, when the B filter 21c illuminates, the amount of light received by the CCD 28 becomes lower than when the other R, G filters 21a, 21b illuminate. Therefore, the electronic shutter function is operated.

Also in the fluorescence mode, the amount of light received by the CCD 28 during the period in which the excitation light is emitted by the E1 filter 22c to obtain a fluorescent image is the amount of reflected light when the R1 and G1 filters 22a, 22b illuminate. The electronic shutter function is activated because it is much lower than the case.

Further, the control circuit 37 controls the moving motor 20 according to the selected mode. Further, the rotation motor 16 is controlled by the control circuit 37, and the output of an encoder (not shown) attached to the rotation shaft of the rotation motor 16 is input to the control circuit 37 and the control circuit 37.
Is the CCD drive circuit 31 in synchronization with the output of this encoder.
And switching of the multiplexer 35 and the like.

Further, the control circuit 37 includes the multiplexer 3
5 is controlled, and in the normal mode, the respective image data captured under the illumination of the R, G, B filters 21a, 21b, 21c are stored in the first frame memory 36a, the second frame memory 36b, and the third frame memory, respectively. Control is performed so that the data is sequentially stored in 36c.

Also in the fluorescent mode, the control circuit 3
7 controls switching of the multiplexer 35, and R1, G
1, each of the signals captured under the illumination of the E1 filters 22a, 22b, and 22c is stored in the first frame memory 36.
a, second frame memory 36b, third frame memory 3
Control is performed so that the data is sequentially stored in 6c. The image data stored in the frame memories 36a to 36c is input to the image processing circuit 38, and the image processing circuit 38 properly performs the assignment process for assigning the input signals to the R, G, and B channel color signals, thereby performing normal operation. After the image processing for converting the tissue portion and the diseased tissue portion into an output signal of a hue that makes it easy to identify, the D / A conversion circuit 39 performs analog R conversion.
It is converted into a GB signal and output to the monitor 5.

In the image processing circuit 38, which is one of the features of this embodiment, the three signals input to it, that is,
3 of a reflected light image signal imaged by reflected light from living tissue by two narrow band illumination lights G1 and R1 and a fluorescence image signal imaged by fluorescence emitted from living tissue by excitation light E1
The two signals are converted by the image processing circuit 38 (appropriately assigned to color signals for color display) and output.

Further, the processor 4A is provided with a dimming circuit 40 for automatically controlling the aperture amount of the light source diaphragm 13 in the light source device 3A based on the signal passed through the preamplifier 32. Further, the dimming circuit 40 is controlled by the control circuit 37.
Controlled. The control circuit 37 also controls a lamp current for driving the lamp 12 of the lamp drive circuit 11 to emit light. The control circuit 37 also performs control operation according to the operation of the scope switch 29.

In the present embodiment, in the endoscope apparatus 1A, the RGB filter 21 of the switching filter 17 of the light source apparatus 3A,
The filter characteristics for the fluorescence observation filter 22 and the excitation light cut filter 27 provided in the imaging optical path of the electronic endoscope 2A are set as shown in FIGS. The feature is that the degree of separation from the lesioned tissue portion can be increased.

Further, the image processing circuit 38 makes it easy to distinguish between normal tissue and diseased tissue by appropriately allocating color signals for color display of three input signals in the fluorescence mode in particular. As described above, the hues are different, and the feature is that the lesion tissue is set to be displayed so as to be in a specific hue.

First, the increase in the degree of separation will be described below with reference to FIG. FIG. 4A shows a characteristic example of the intensity distribution with respect to the wavelength of fluorescence obtained from the biological tissue.
(B) shows an example of characteristics of intensity distribution with respect to the wavelength of reflected light obtained from living tissue.

As can be seen from FIG. 4A, a distribution characteristic having a peak near 520 nm is shown. In the present embodiment, the transmission characteristic by the excitation light cut filter 27 is 520n.
The S / N of the obtained fluorescence image is increased by setting the wavelength band near m to be included.

Further, in the intensity characteristic of the reflected light in FIG. 4B, the absorption by hemoglobin is large near 550 nm, and there is a valley where the reflection intensity decreases near this wavelength. In the vicinity of 600 nm, there is a non-absorption band due to hemoglobin. The center wavelengths of the two filters 22a and 22b (G1 and R1 in the figure) are 550 nm and 600 nm.
Is set to.

That is, in the present embodiment, the band of the R1 filter 22a is set to the portion where the absorbance of oxyhemoglobin is low, and the band of the G1 filter 22b is set to the portion where the absorbance of oxyhemoglobin is high.

Incidentally, G1 which becomes the first and second illumination light (reflected light) which is illuminated in the fluorescence mode and is imaged by its reflected light,
The wavelength width of the light of R1 is set to several tens nm, more specifically to 20 nm (it may be set to 20 nm or less as described later). The light transmittance of the blue region (the long wavelength region) shielded by the E1 filter 22c and the blue region (the short wavelength region) shielded by the excitation light cut filter 27 is OD4 (1/10000) or less. It is set.

As described above, the wavelength (center wavelength) of the two reflected light images in the fluorescence mode is set to 55.
The reason for setting 0 nm and 600 nm will be described with reference to FIG.

FIG. 5 shows two reflected light intensities and fluorescence intensities of 3
A state in which a normal portion and a lesion portion are distributed on the axis space coordinate set as the axis is shown. In FIG. 5, a portion indicated by a satin pattern indicates a normal tissue in the living tissue, and a portion indicated by a diagonal line indicates a diseased tissue in the living tissue.

The smaller the overlapping portion of the normal tissue and the diseased tissue is, the easier the distinction between the normal tissue and the diseased tissue is. Therefore, in this embodiment, the overlapping portion is minimized to 2 The band of one reflected light is calculated using a statistical method (specifically, Fisher's discriminant function). That is, due to the overlapping distribution of normal tissue and diseased tissue, the separation ability S
Is calculated by the following formula.

Separation power S = 1- (portion where distributions of normal tissue and diseased tissue overlap) / (entire distribution) Then, the central wavelengths of the first reflected light and the second reflected light are changed to obtain The separability S which is calculated is calculated.

FIG. 6 shows the separability S obtained for the central wavelength of the second reflected light when the central wavelength of the first reflected light is changed as a parameter. Here, with the center wavelength of the first reflected light as a parameter,
The case where the thickness is changed to 0 nm and 600 nm is shown.

The central wavelength of the first reflected light is 550
It can be seen that the maximum resolution S is obtained when the center wavelength of the second reflected light is 600 nm in nm. In addition, when the center wavelengths of the first reflected light and the second reflected light are interchanged, that is, when the center wavelength of the first reflected light is 600 nm and the center wavelength of the second reflected light is 550 nm, the largest separation occurs. Noh S is obtained.

Further, in FIG. 7, the central wavelength of the first reflected light is 5
The resolution S obtained when the wavelength width is 50 nm and the wavelength width is changed as a parameter is shown. In Figure 7, the wavelength width is 8
The case where the thickness is 0 nm, 20 nm, and 10 nm is shown.

From FIG. 7, the central wavelength of the first reflected light is set to 550
It can be seen that a large resolution S is obtained when nm is approximately 20 nm or less. From FIG. 7, 1 from 20 nm
When the thickness is 0 nm, a larger resolution S is obtained, but when the wavelength width is made smaller, the strength is lowered and the S / N is lowered.
Therefore, in the present embodiment, the wavelength width is set to 20 nm. Depending on the S / N ratio of the signal processing system of the processor 4A, the wavelength width may be 20 nm or less, such as 10 nm.

From FIGS. 6 and 7, in the present embodiment, the wavelengths of the first and second reflected lights (illumination light) are set to 550 nm and 600 nm, respectively, as shown in FIG. The wavelength width is set to 20 nm so that a large resolution S can be obtained, that is, normal tissue and diseased tissue can be distributed in a state where they are separated as much as possible.

In the present embodiment, the intensity of the fluorescence image is much weaker than that of the reflected light, and therefore, as shown in FIG. 4A, at least the wavelength band near 520 nm at which the intensity peaks is included. An excitation light cut filter 27 having a characteristic of obtaining a fluorescence image is adopted. As a result, S / N
It is possible to obtain a good fluorescent image.

Further, in the present embodiment, the image processing circuit 3
8, the three input signals are set to be appropriately assigned to the three color signals so that the normal tissue and the diseased tissue have a hue that is easily discriminated on the display image. Pseudo-color display is possible in a state in which normal tissue and diseased tissue are distributed in a state where they can be easily distinguished on the chromaticity diagrams shown in FIGS. 8 to 11.

The operation of the present embodiment having such a configuration will be described below. As shown in FIG. 1, the light source connector 10 of the electronic endoscope 2A is connected to the light source device 3A, and the signal connector (not shown) of the electronic endoscope 2A is connected to the processor 4.
Connect to A. Then, the connection state as shown in FIG. 1 is set, the power of each device is turned on, and the operation state is set.
Then, the control circuit 37 performs an initial setting operation, and in this initial setting state, performs control for setting to operate in the normal mode, for example.

In this normal mode, the control circuit 37 controls the moving motor 20 of the light source device 3A to set the switching filter 17 so that the RGB filter 21 on the inner peripheral side thereof is positioned in the illumination optical path.

Then, the rotary motor 16 is rotated. As for the white light of the lamp 12, the R, G, B filters 21a, 21b, 21c of the switching filter 17 are sequentially arranged in the illumination light path, and the R, G, B illumination lights are emitted to the observation target side. .

In this normal mode, the illumination light (to the side of the object to be observed) by the switching filter is R, G, B filters 21.
a, 21b, and 21c are sequentially arranged in the illumination optical path.
The signal illuminated by the R, G, and B lights and picked up by the CCD 28 is amplified and A / D converted, and then the multiplexer 35.
Are sequentially switched by the control circuit 37, so that the first
The frames are sequentially stored in the frame memory 36a, the second frame memory 36b, and the third frame memory 36c.

The image data of the R, G, and B color components stored in the frame memories 36a to 36c are simultaneously read in a predetermined frame period (for example, 33 ms, that is, 1/30 seconds), and are read by the image processing circuit 38. Is entered.

In the normal mode, the image processing circuit 38
Output the input signal as it is. That is, R, G, B output from the first frame memories 36a to 36c, respectively.
The color signal of D passes through the image processing circuit 38 (gamma correction or contour enhancement may be performed as necessary) D /
It is output to the A conversion circuit 39.

In this manner, the analog standard video signal, here the RGB signal, is output to the monitor 5 from the R, G and B channels via the D / A conversion circuit 39,
On the display surface of the monitor 5, a normal observation image is displayed in color (reflecting the color tone when a subject is directly observed when white light is emitted).

As described above, the amount of reflected light on the subject side when illuminated through the B filter 21c is cut off by the excitation light cut filter 27 on the short wavelength side and is received by the CCD 28. The amount of light received by the image becomes smaller than the amount of light received by the other R and G color component images, and the white balance is lost as it is.

To prevent this, the control circuit 37 uses C
The amplification factor of the CCD 28 when the image is picked up during the illumination period of the B filter 21c via the CD drive circuit 31 is doubled, for example. In addition, the control circuit 37 is the lamp drive circuit 11
Is controlled to increase the lamp current for driving the lamp 12 in the illumination period in the B filter 21c, for example, to be larger than the value of the normal lamp current to increase the B illumination light amount.

Further, the control circuit 37 is the CCD drive circuit 31.
To operate the function of the electronic shutter of the CCD 28. That is, in the R and G illumination periods, the CCD 28 is driven so that the image pickup is performed only in a part of the illumination period, and the CCD 28 is driven so that the image pickup period is short.
During the illumination period, the entire illumination period is used for image capturing, so that the image capturing period is long.

In this way, the monitor 5 displays a normal image with a white balance. It should be noted that the setting of the image pickup period by the electronic shutter is such that when a white subject is picked up in advance, the subject is displayed white on the monitor 5.
A specific value of the image pickup period is stored in a memory or the like (not shown) in the control circuit 37 (or at the time of initial setting after the power is turned on, a white subject is imaged and the image pickup period by the electronic shutter is set. It may be set specifically).
At this time, the value of the CCD amplification factor and the value of the lamp current may be stored instead of the image pickup period of the electronic shutter, and these may be used alone or in combination.

In this way, the subject can be observed in the normal mode, and for example, when fluorescence observation is to be performed on the subject such as the affected area of interest, the fluorescence mode switch of the mode changeover switch of the scope switch 29 is operated.

Then, in response to this operation signal, the control circuit 37 causes the light source device 3A to drive the moving motor 20 to move the switching filter 17, and the fluorescence observation filter 22 is arranged on the illumination optical path. Set to and switch to fluorescence mode.

When the fluorescence mode is set, the electronic endoscope 2
The light guide fiber 9 of A has illumination light in a fluorescence mode,
That is, the light of R1, G1, and E1 shown in FIG. 3B is sequentially supplied.

Then, the light of R1, G1, and E1 is sequentially irradiated to the subject. In the case of the illumination of R1 and G1, the operation is the same as the case where the R and G lights in the normal mode are sequentially irradiated. That is, in this case, the CCD 28 receives the reflected light from the R1 and G1 subjects. In this case, the CCD 28 is not affected by the excitation light cut filter 27.
Will be imaged.

On the other hand, when the excitation light E1 is irradiated, the reflected light of the excitation light E1 is the excitation light cut filter 2
At 7, the light is almost completely shielded, and the fluorescence from the subject side within the transmission band of the excitation light cut filter 27 is received.

Since the intensity of this fluorescence is much smaller than the intensity of the reflected light on the R1 and G1 subjects, the R, G illumination, the B illumination in the above-described normal mode and the signal processing in those cases are performed. The operation similar to
A bright fluorescent image is displayed so that it can be easily compared with the image of the reflected light of the subject of G1 and G1.

Specifically, when the reflected light from the R1 and G1 subjects is to be imaged, the image data imaged by the CCD 28 only in a part of the illumination period by the electronic shutter is transferred to the first frame memory 36a by the electronic shutter. Second frame memory 36b
To be stored in.

On the other hand, when the excitation light of E1 is irradiated and the fluorescence image is captured, the amplification factor of the CCD 28 is increased, for example, from 10 times to 100 times, and the lamp current is also increased. The illumination light quantity of the excitation light is also increased. Then, the fluorescence image data captured in this case is stored in the third frame memory 36c. Then, the first frame memory 36a to the third frame memory 36c are cycled in one frame period.
Image data is read at the same time and input to the image processing circuit 38.

The image processing circuit 38 receives the input signals R1, G1,
EX (where R1 and G1 are the signals of the reflection image by the narrow band illumination light and correspond to the second and first reflection lights of FIGS. 6 and 7, and EX is the signal of the fluorescence image by the excitation light E1. (Shown) are appropriately assigned to the R, G, and B channels.

In the case of the fluorescence mode, the image signal EX consisting of the fluorescence wavelength band is set to the G channel, and one of the reflected light wavelength bands having two different center wavelengths and wavelength widths is set to the R channel.
A channel and another reflected light wavelength band are assigned to the B channel.

Specifically, the image signal EX consisting of the fluorescence wavelength band is assigned to the G channel, and the remaining two reflected light image signals R1 and G1 are assigned to B, R or R, B. That is, EX → G, R1 → B, G1 → R (assignment 1) or EX → G, R1 → B, G1 → R (assignment 2).

In this case, as shown in FIG. 8 or 9, the normal tissue part and the diseased tissue part are different from each other in the chromaticity diagram (corresponding state), and in particular, the diseased tissue part is in a substantially single hue. Then, it is displayed on the monitor 5 in pseudo color. In the case of FIG. 8 corresponding to allocation 1, the diseased tissue portion is limited to around the pink hue.

Further, in the case of FIG. 9 corresponding to the case of allocation 2, the lesioned tissue portion is limited to the vicinity of the purple hue. The display mode corresponding to FIG. 8 or 9 can be switched to each other by operating the switching mode in the fluorescence mode. Then, the user can display it as he prefers.

Therefore, in the case of FIG. 8, the operator can determine that there is a high possibility that it is a lesioned tissue by paying attention to the portion displayed near the pink hue. Also, the operator is
In this case, it is possible to determine that there is a high possibility that it is a lesioned tissue by paying attention to the portion displayed near the purple hue.

When it is determined that the possibility of lesioned tissue is high in the pseudo color display state corresponding to the chromaticity diagram as shown in FIG. 8 or 9, the scope switch 29 is set to the fluorescence mode. When the prepared lesion tissue mode switch is operated, the allocation by the image processing circuit 38 is further changed and set by the control by the control circuit 37.

Specifically, the image signal EX having the fluorescence wavelength band is assigned to the B channel, and the remaining two reflected light image signals R1 and G1 are assigned to G, R or R, G. That is, EX → B, R1 → G, G1 → R (assignment 3) or EX → B, R1 → R, G1 → G (assignment 4).

Allocation 3 or 4 is shown in FIG. 10 or FIG.
An image in the fluorescence mode, that is, two reflected light images and a fluorescence image are displayed in pseudo color in a state corresponding to the chromaticity diagram as shown in FIG.

In FIG. 10 or FIG. 11, the diseased tissue is displayed so as to be distributed in a plurality of hues, so it may not be appropriate when diagnosing normal tissue and diseased tissue from the beginning, but FIG. Alternatively, in the case where it is diagnosed in FIG. 9 that the possibility of the diseased tissue is high, further, FIG.
When the display mode as shown in (3) is set, the state of the diseased tissue can be easily diagnosed in more detail due to the difference in hue. For example,
The change in hue makes it easier to judge the degree of progression of the lesion.

As described above, according to the present embodiment, when displaying an image by two reflected lights and a fluorescent image in pseudo color, the overlap between the normal tissue and the diseased tissue is reduced and the separability S is increased. The wavelength of the image by the reflected light is set to an appropriate value so that the lesion tissue is displayed in pseudo-color so that it enters a substantially single hue that is easy to identify, unlike normal tissue. When diagnosing whether it is a part of tissue, the operator can easily diagnose the diseased tissue. That is, it is possible to provide an environment that is easy to diagnose.

The excitation light cut filter 27 arranged in front of the image pickup device of the electronic endoscope 2A cuts the excitation light including a part of the blue wavelength band, and the excitation cut filter 27 is normally observed. In order to transmit light other than part of the blue light in the visible range (transmitting part of the blue light and the entire wavelength bands of green and red), one image sensor is inserted. By arranging at the tip portion 8 of the unit 7, it is possible to display the normal image and the fluorescent image by picking up the normal image and the fluorescent image and performing signal processing.

Therefore, the insertion portion 7 of the electronic endoscope 2A can be made thin (compared to the case where a plurality of image pickup elements are incorporated),
Insertion can be used and the applicable range can be expanded,
The pain to the patient during insertion can be reduced. Also, the operator can easily insert the body into the body cavity. Further, since only one image sensor is required, cost reduction can be achieved.

Further, since blue in the wavelength band (region) of visible light is used as the excitation light, a halogen lamp, a xenon lamp or the like that can be used for normal illumination (white illumination) is used as the lamp 12 of the light source device 3A. Can be used. Further, compared with the case where ultraviolet light or the like is used as the excitation light, there are advantages that the transmission loss due to the light guide fiber 9 can be reduced and that for normal illumination can be used as it is. In particular, it is possible to realize the endoscope apparatus 1A that can display the image images (by the fluorescence image and the reflected light image) in pseudo color so that the normal tissue and the diseased tissue can be easily distinguished with a simple configuration.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. The configuration of this embodiment is the same as that of the first embodiment, and the configuration of FIG.
A part of the characteristic of the excitation light cut filter 27 shown in (C) is changed.

FIG. 12 shows the characteristics of the intensity of fluorescence obtained from living tissue containing porphyrin with respect to the wavelength. In the case of living tissue containing porphyrin as shown in this figure, 62
There may be a peak emitting fluorescence from porphyrin in a wavelength band slightly longer than 0 nm. In order to eliminate the influence of fluorescence due to this porphyrin, in the present embodiment, the superwavelength side in the transmission characteristic of the excitation light cut filter 27 is cut at 620 nm as shown by the one-dot chain line in FIG. The fluorescent light on the side was not received by the CCD.

That is, the excitation light cut filter 27 is set so as to transmit fluorescence from, for example, 470 nm to 620 nm on the long wavelength side on the short wavelength side as in the first embodiment. Others are the same as those in the first embodiment.

According to the present embodiment, in addition to the effects of the first embodiment, even when observing a living tissue part containing porphyrin, the influence of porphyrin is eliminated and normal tissue and lesion tissue are removed. It is possible to provide an endoscopic device capable of displaying a pseudo color in a color tone that makes it easy to distinguish between and.

[Additional Notes] 1. A light source for generating excitation light for exciting illumination light and fluorescence in two different wavelength bands, a light guide means for guiding the illumination light and the excitation light, and the light guide means. The illuminating light is applied to the living tissue via the light source, and each of the reflected light is reflected by the illuminating light.
An image pickup means for picking up one reflected light image, a fluorescence image by fluorescence excited by the excitation light, an image processing means for processing the two reflected light images and the fluorescence image, and constructing a processed image; In an endoscopic device including display means for displaying an image, when two different reflected light and fluorescence intensities from a living tissue are plotted on a spatial coordinate axis having three axes, a normal tissue and a diseased tissue have three axial spatial coordinate axes. The wavelengths of the reflected light and the fluorescence are selected so as to be separated as described above, and the processed image processed by the image processing means has different hues between normal tissue and diseased tissue, and the diseased tissue falls into a specific substantially one hue. Thus, the reflected light and the fluorescence are assigned to a specific color signal, processed, and displayed.

1 '. A light source device that generates excitation light for exciting illumination light and fluorescence in two different wavelength bands, a light guide unit that guides the illumination light and the excitation light, and the living tissue to the biological tissue via the light guide unit. An endoscope having two reflected light images each of which is reflected by reflected light that is irradiated with illumination light and an imaging unit that captures a fluorescence image of fluorescence excited by the excitation light, and the two reflected light images. And an image processing means for processing the fluorescence image to construct a processed image and outputting the processed image to the image display means. In the endoscope apparatus, two different reflected light from the biological tissue and the fluorescence intensity are set to three axes. The wavelengths of the reflected light and the fluorescence are selected so that the normal tissue and the diseased tissue are separated on the three-axis space coordinate axes when plotted on the spatial coordinate axis, and the processed image processed by the image processing means is the normal tissue. And lesion tissue in hue Unlike, as diseased tissue to enter the particular substantially one color, the reflected light and the fluorescence was allocation process to a particular color signal, the endoscope apparatus characterized by being displayed. 2. In Supplementary Note 1, one of the two selected reflected light wavelength bands is a wavelength band including the absorption band of hemoglobin light, and the other is a wavelength band including the non-absorption band of hemoglobin light. It is characterized by 3. In Appendix 1, the selected one fluorescence wavelength band is a wavelength band including 520 nm, and the two reflected light wavelength bands are wavelength bands including 550 nm and 600 nm, respectively. 4. In Appendix 3, one selected fluorescence wavelength band is characterized by including 520 nm and excluding a band of 620 nm or more.

5. In Appendix 3, the wavelength width of the two selected reflected light wavelength bands is 20 nm to 20 nm.
It is characterized by the following. 6. In Appendix 1, in the processed image, an image signal from one fluorescence wavelength band is green, one image signal of two reflected light wavelength bands of two different wavelength bands is red or blue, and the other is blue. , Or red color signals are assigned and processed. 7. A light source for illuminating illumination light of two different wavelength bands and excitation light for exciting fluorescence, a living tissue irradiated with the illumination light, and two reflected light images each of which is reflected light, and The illumination light is reflected by the biological tissue, and two reflection images are formed by the reflected light reflected by the living tissue, an imaging unit that captures a fluorescence image of fluorescence excited by the excitation light, and the two reflection light images and the fluorescence image. In an endoscopic device including an image processing unit configured to process a processed image and a processed image and a display unit configured to display the processed image, a space in which two different reflected light from the biological tissue and the intensity of the fluorescence are three axes The wavelengths of the reflected light and the fluorescence are selected so that the normal tissue and the diseased tissue are separated on the three-axis space coordinate axes when plotted on the coordinate axes, and the processed images processed by the processing means have a plurality of diseased tissues. of So as to extend over the phase, the reflected light and the fluorescence was allocation process to a particular color signal, the endoscope apparatus characterized by being displayed.

8. Since the illumination light of two different wavelength bands and the excitation light for exciting the fluorescence are sequentially illuminated, the two band filters that pass the wavelength band and the excitation filter that passes the excitation light can be switched. Light source arranged like
The living tissue is irradiated with the two illumination lights and reflected
In order to capture two reflected light images and a fluorescence image of fluorescence excited by the excitation light, an image pickup means that blocks the excitation light and has a built-in fluorescence detection filter that transmits the fluorescence and the reflected light; In an endoscopic device including image processing means for processing one reflected light image and fluorescent image to construct a processed image, and display means for displaying the processed image, wavelength bands of the two band filters and the fluorescence detection filter are provided. Is a band so that normal tissue and diseased tissue are separated on the three-axis spatial coordinate axis when the reflected light from the biological tissue by two different band filters and the fluorescence by the fluorescence detection filter are plotted on the three-axis spatial coordinate axis. An endoscope apparatus characterized in that wavelengths of a filter and a fluorescence detection filter are selected.

8 '. In order to sequentially illuminate the illumination light of two different wavelength bands and the excitation light for exciting the fluorescence, the two band filters that pass the wavelength band and the excitation filter that passes the excitation light are arranged to be switchable. Since the light source and the living tissue are irradiated with the two illumination lights and the reflected two reflected light images and the fluorescence image by the fluorescence excited by the excitation light are captured, the excitation light is blocked and the fluorescence is removed. And an image processing unit that incorporates a fluorescence detection filter that transmits reflected light, and an image processing unit that processes the two reflected light images and the fluorescence image to construct a processed image and outputs the processed image to the image display unit. In the endoscopic device, the wavelength bands of the two band-pass filters and the fluorescence detection filter are:
When the reflected light from two different band filters from the biological tissue and the fluorescence from the fluorescence detection filter are plotted on the spatial coordinate axes with the three axes, a band filter is used so that normal tissue and diseased tissue are separated on the three-axis spatial coordinate axes. An endoscope apparatus characterized in that a wavelength of a fluorescence detection filter is selected. 9. In Appendix 8, each band-pass filter that limits the wavelength band of the reflected light image to a specific wavelength includes a filter that transmits a wavelength band that includes the absorption band of hemoglobin light and a wavelength band that includes the non-absorption band of hemoglobin light. Is a filter that transmits light. 10. In Supplementary Note 8, each bandpass filter that limits the wavelength band of the reflected light image to a specific wavelength is a filter that transmits a wavelength band including 550 nm and a filter that transmits a wavelength band including 600 nm. The fluorescence detection filter that limits the band to a specific wavelength is characterized by being a filter that transmits a wavelength band including 520 nm.

11. In Supplementary Note 10, the wavelength width transmitted by each bandpass filter that limits the wavelength band of the reflected light image to a specific wavelength is 20 nm or less or 20 nm or less. 12. In Supplementary Note 10, the fluorescence detection filter that limits the wavelength band of the fluorescence image to a specific wavelength is characterized by including 520 nm and blocking light of 620 nm or more.

13. In order to sequentially illuminate the illumination light of two different wavelength bands and the excitation light for exciting the fluorescence, the two band filters that pass the wavelength band and the excitation filter that passes the excitation light can be switched. In order to capture the two reflected light images reflected by the light source arranged in such a manner that the living tissue is irradiated with the two illumination lights and the fluorescence image due to the fluorescence excited by the excitation light, the excitation light is An image pickup unit that has a built-in fluorescence detection filter that blocks the fluorescence and transmits the fluorescent light and the reflected light; an image processing unit that processes the two reflected light images and the fluorescent image to construct a processed image; In the endoscopic device including display means for displaying, the wavelength bands of the two band-pass filters and the fluorescence detection filter are the reflected light from the biological tissue by the two different band-pass filters and the fluorescence detection filter. When plotted on space coordinate axis and three axes fluorescence by filter, normal tissue and diseased tissue 3
The wavelengths of the band-pass filter and the fluorescence detection filter are selected so that they are separated on the axial space coordinate axis, and the image processing means has different hues between the normal tissue and the lesion tissue, and the lesion tissue has a specific
An endoscope apparatus including a processing circuit for allocating and processing the reflected light and the fluorescence to a specific color signal so as to enter one hue. 13 '. In order to sequentially illuminate the illumination light of two different wavelength bands and the excitation light for exciting the fluorescence, the two band filters that pass the wavelength band and the excitation filter that passes the excitation light are arranged to be switchable. Since the light source and the living tissue are irradiated with the two illumination lights and the reflected two reflected light images and the fluorescence image by the fluorescence excited by the excitation light are captured, the excitation light is blocked and the fluorescence is removed. And an image processing unit that incorporates a fluorescence detection filter that transmits reflected light, and an image processing unit that processes the two reflected light images and the fluorescence image to construct a processed image and outputs the processed image to the image display unit. In the endoscopic device, the wavelength bands of the two band-pass filters and the fluorescence detection filter have three axes of reflected light from two different band filters from the biological tissue and fluorescence from the fluorescence detection filter. When plotted on the spatial coordinate axis, the wavelengths of the bandpass filter and the fluorescence detection filter are selected so that the normal tissue and the diseased tissue are separated on the three-axis spatial coordinate axis, and the image processing unit causes the hues of the normal tissue and the diseased tissue to be different. Differently, the endoscopic device includes a processing circuit for allocating the reflected light and the fluorescence to a specific color signal so that the diseased tissue enters a specific hue. 14. In Supplementary Note 13, the image processing means displays the fluorescence image in a G
It is characterized in that the reflected light image is assigned to the R channel or the B channel color signal and processed.

[0095]

As described above, according to the present invention, 2
A light source that generates excitation light for exciting illumination light and fluorescence of three different wavelength bands, a light guide unit that guides the illumination light and the excitation light, and the illumination light to the biological tissue via the light guide unit. Of the reflected light reflected by each of the two reflected light images, the image pickup means for picking up the fluorescent image of the fluorescent light excited by the excitation light, and the two reflected light images and the fluorescent image. In an endoscopic device including an image processing means for constructing a processed image and a display means for displaying the processed image, two different reflected light from the biological tissue and the intensity of fluorescence are plotted on the spatial coordinate axis with three axes. At this time, the wavelengths of the reflected light and the fluorescence are selected so that the living tissue and the diseased tissue are separated on the three-axis space coordinate axes, and the processed image processed by the processing means has different hues between the normal tissue and the diseased tissue, Lesion tissue To enter a particular substantially one color,
Since the reflected light and the fluorescence are assigned to specific color signals and displayed, pseudo-color display can be performed as an image in which normal tissue and diseased tissue can be easily distinguished.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an endoscope device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a switching filter provided with a normal observation filter and a fluorescence observation filter.

FIG. 3 is a diagram showing transmission characteristics with respect to wavelengths of a normal observation filter, a fluorescence observation filter, and an excitation light cut filter.

FIG. 4 is a diagram showing a characteristic example of intensity distribution with respect to wavelength of a fluorescence image and a reflected light image obtained from a living tissue.

FIG. 5 is a diagram showing a state in which a normal portion and a lesion portion are plotted and distributed on an axial space coordinate having three axes of fluorescence intensity and two reflected light intensities.

FIG. 6 is a diagram showing how the separability changes with respect to the central wavelength of the second reflected light when the wavelength of the first reflected light is used as a parameter.

FIG. 7 is a diagram showing how the separability changes with respect to the central wavelength of the second reflected light when the wavelength width of the first reflected light is used as a parameter.

FIG. 8 is a chromaticity diagram showing a distribution of a normal portion and a lesion portion obtained when a fluorescence image is assigned to the G channel and images of the first and second reflected lights are assigned to the B and R channels.

FIG. 9 is a chromaticity diagram showing a distribution of a normal portion and a lesion portion obtained when a fluorescence image is assigned to the G channel and images of the first and second reflected lights are assigned to the R and B channels.

FIG. 10 is a diagram showing a chromaticity diagram showing the distribution of normal parts and lesion parts obtained when the fluorescence image is set to the B channel and the images of the first and second reflected lights are set to the G and R channels.

FIG. 11 is a diagram showing a chromaticity diagram showing the distribution of normal parts and lesion parts obtained when the fluorescence image is set to the B channel and the images of the first and second reflected lights are set to the R and G channels.

FIG. 12 is a diagram showing the transmission characteristics and the like of the excitation light cut filter according to the second embodiment of the present invention.

[Explanation of symbols]

1A ... Endoscopic device 2A ... Electronic endoscope 3A ... Light source device 4A ... Processor 5 ... Monitor 7 ... insertion part 8 ... Tip 9 ... Light guide fiber 10 ... Connector 11 ... Lamp driving circuit 12 ... Lamp 13 ... Light source diaphragm 14 ... Switching filter section 16 ... Rotating motor 17 ... Switching filter 18 ... rack 20 ... Motor for movement 21 ... RGB filter 22 ... Filter for fluorescence observation 25 ... Objective lens system 27 ... Excitation light cut filter 28 ... CCD 29 ... Scope switch 31 ... CCD drive circuit 34 ... A / D conversion circuit 36a to 36c ... Frame memory 37 ... Control circuit 38 ... Image processing circuit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsuichi Imaizumi             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. (72) Inventor Mamoru Kaneko             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. (72) Inventor Kazuhiro Gono             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. F-term (reference) 2G043 AA03 BA16 CA05 EA01 FA01                       FA06 GA02 GA21 GB18 GB19                       HA01 HA05 JA03 KA02 KA05                       LA03 NA06                 4C061 BB08 HH54 LL02 MM03 QQ04                       WW04 WW17

Claims (2)

[Claims] 1. A light source that generates excitation light for exciting illumination light and fluorescence of two different wavelength bands, a light guide unit that guides the illumination light and the excitation light, and through the light guide unit. The living tissue is irradiated with the illumination light and two reflected light images are formed by the reflected light, and
An imaging unit that captures a fluorescent image of fluorescence excited by the excitation light, an image processing unit that processes the two reflected light images and a fluorescent image to construct a processed image, and a display unit that displays the processed image. In the endoscopic device consisting of the above, when the two different reflected light from the biological tissue and the intensity of the fluorescence are plotted on the spatial coordinate axes with the three axes, the normal tissue and the diseased tissue are separated on the three-axis spatial coordinate axes. The wavelengths of the reflected light and the fluorescent light are selected, and the processed image processed by the image processing means has different hues between the normal tissue and the diseased tissue, and the reflection tissue is adjusted so that the diseased tissue enters a specific substantially one hue. An endoscope apparatus characterized in that light and fluorescence are assigned to a specific color signal, processed, and displayed. 2. Since the illumination light of two different wavelength bands and the excitation light for exciting fluorescence are sequentially illuminated, the two bandpass filters that pass the wavelength band and the excitation filter that passes the excitation light are switchable. And the light source arranged in such a manner that the living tissue is irradiated with the two illumination lights and reflected.
An image pickup unit having a built-in fluorescence detection filter that blocks the excitation light and transmits the fluorescence and the reflected light, in order to capture two reflected light images and a fluorescence image of the fluorescence excited by the excitation light; An endoscopic device comprising image processing means for processing one reflected light image and fluorescence image to construct a processed image, and display means for displaying the processed image, wherein wavelength bands of the two band-pass filters and the fluorescence detection filter are provided. Is a band so that normal tissue and diseased tissue are separated on the three-axis spatial coordinate axis when the reflected light from the biological tissue by two different band filters and the fluorescence by the fluorescence detection filter are plotted on the three-axis spatial coordinate axis. An endoscope apparatus characterized in that wavelengths of a filter and a fluorescence detection filter are selected.