JP2008272507A - Endoscope apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endoscope apparatus displaying an image to be easily discriminated between normal tissues and diseased tissues. <P>SOLUTION: Illuminating light of a plurality of different wavelength bands in a light source for generating illuminating light of a plurality of different wavelength bands and excitation light for exciting fluorescence has such a wavelength characteristic that the resolution S shows the maximum value when the resolution S of an overlap between the distribution of normal tissues and the distribution of diseased tissues is the resolving power S=1-(an overlap part of the distribution of normal tissues and the distribution of diseased tissues)/the whole distribution, based on the intensity distribution characteristic to the wavelength of the reflected light or the fluorescence obtained from a biotissue. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an endoscope apparatus for diagnosing normal tissue and diseased tissue by obtaining a reflection image and a fluorescence image.

  In recent years, endoscopes have been widely used in the medical field and the industrial field. 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 can easily distinguish between a normal tissue and a diseased tissue has been proposed. .

For example, Japanese Patent Publication No. 5-37650 as a first conventional example 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 Japanese Patent Laid-Open No. 10-309282 as a second conventional example, normal tissue and diseased tissue are distinguished from each other by irradiating excitation light and from two fluorescent images having different wavelength bands and a reflection image by the excitation light. An apparatus for obtaining such an image is disclosed.
Japanese Patent Laid-Open No. 2000-270265 as a third conventional example discloses an apparatus for superimposing a fluorescent image and a background image.

  In the first prior art, the regression line for the target tissue is derived using the fluorescence image and the reference image, but only the wavelength of the reference image is matched with the wavelength of the fluorescence image. There is a possibility that the function of discriminating between and the diseased tissue is not sufficient.

Further, the configuration of the second conventional example is complicated.
Further, the third conventional example has a drawback that the function of obtaining an image that can easily distinguish between normal tissue and diseased tissue is lowered because the reflected light is broadband.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide an endoscope apparatus that can obtain an image that can easily identify a normal tissue and a diseased tissue.

An endoscope apparatus according to the present invention irradiates a living tissue with illumination light of a plurality of different wavelength bands, a light source that generates excitation light for exciting fluorescence, and the illumination light and excitation light from the light source. Then, the reflected light image signal and the fluorescence image signal captured by the imaging means for capturing each reflected light image by the reflected light reflected and the fluorescence image by the fluorescence excited by the excitation light are input, and a predetermined value is input. An endoscopic device comprising an image processing device that performs image processing,
The image processing apparatus includes an identification unit that identifies a normal tissue and a diseased tissue in a living tissue based on the reflected light image signal and the fluorescence image signal input from the imaging unit,
The illumination light of the plurality of different wavelength bands in the light source is based on the intensity distribution characteristic with respect to the wavelength of the reflected light or the fluorescence obtained from the living tissue, and the separation ability of the overlap between the distribution of the normal tissue and the distribution of the diseased tissue When S is the resolution S = 1− (the portion where the distribution of the normal tissue and the distribution of the lesion tissue overlap) / the entire distribution,
The resolution S used by the discriminating means has a wavelength characteristic showing a maximum value.

  According to the present invention, it is possible to obtain an image that allows easy identification of normal tissue and diseased tissue.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIGS. 1 to 11 relate to a first embodiment of the present invention, FIG. 1 shows the overall configuration of the endoscope apparatus of the first embodiment, and FIG. 2 shows a normal observation filter and a fluorescence observation filter. 3 shows the transmission characteristics with respect to the wavelengths of the normal observation filter, the fluorescence observation filter and the excitation light cut filter, and FIG. 4 shows the intensity distribution with respect to the fluorescence wavelength obtained from the living tissue. And a characteristic example of intensity distribution with respect to the wavelength of reflected light obtained from a living tissue, and FIG. 5 shows normal portions and lesions on axial space coordinates with three axes of fluorescence intensity and two reflected light intensities. FIG. 6 shows a change in the separation power with respect to the center wavelength of the second reflected light when the wavelength of the first reflected light is used as a parameter. FIG. Parameter of reflected light wavelength FIG. 8 and FIG. 9 show the change of the separation power with respect to the center wavelength of the second reflected light in the case of the above, and FIGS. 8 and 9 show the fluorescence image as the G channel and the first and second reflected light images as the B and R channels. FIG. 10 and FIG. 11 show the chromaticity diagram showing the distribution of the normal part and the lesion part obtained when the R and B channels are set, and FIGS. 10 and 11 show the first and second reflected light images as the B channel. Is a chromaticity diagram showing the distribution of the normal part and the lesion part obtained when G is set to the G, R channel and the R, G channel.

  An endoscope apparatus 1A having a normal observation mode and a fluorescence observation mode according to the first embodiment of the present invention shown in FIG. 1 includes an electronic endoscope 2A for insertion into a body cavity and observation, A light source device 3A that emits observation light and excitation light, 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

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

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

  The switching filter unit 14 is rotated by a motor 16 for rotation, and a switching filter 17 for switching a filter arranged on the optical path by a motor 20 for movement, and a pinion screwed into a rack 18 attached to the motor 16 for rotation. The motor 19 for rotation is provided with the motor 20 for movement which moves the switching filter 17 in the direction perpendicular | vertical to an optical axis with the motor 16 for rotation.

  As shown in FIG. 2, the switching filter 17 is provided with a normal observation RGB filter 21 and a fluorescence observation filter 22 concentrically on the inner peripheral side and the outer peripheral side, and drives the moving motor 20. To set the normal illumination filter 21 on the optical path to set the operation state in the normal image mode (also referred to as the normal mode), or switch from the normal illumination filter 21 to the fluorescence illumination filter 22 to obtain the fluorescence image mode (fluorescence). It is possible to switch to the operation state set in (also called mode).

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

  Further, the transmission characteristics of the R, G, and B filters 21a, 21b, and 21c are filter characteristics that respectively transmit light in the wavelength bands of 600 to 700 nm, 500 to 600 nm, and 400 to 500 nm, as shown in FIG. Have In FIG. 3 and the like, symbols R, G, and B corresponding to the filter transmission characteristics are used instead of symbols 21a, 21b, and 21c (the same applies to the fluorescence observation filter 22 described later).

In addition, the fluorescence observation filter 22 includes three narrow-band red (R1), narrow-band green (G1), and narrow-band excitation light R1, G1, and E1 filters 22a, 22b, and 22c in the circumferential direction. They are provided so as to be equally divided, and each is sequentially inserted in the optical path by being rotationally driven by the rotation motor 16.
Further, the transmission characteristics of the R1, G1, and E1 filters 22a, 22b, and 22c are filter characteristics that transmit light in each wavelength band of 590 to 610 nm, 540 to 560 nm, and 390 to 445 nm as shown in FIG. Have.

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

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

The distal end portion 8 is provided with an observation window adjacent to the illumination window. The observation window is spatially incident to the objective lens system 25 for forming an optical image and to focus from a far point to a near point. A diaphragm 26 that limits the amount of light, an excitation light cut filter 27 that cuts excitation light, and a charge coupled device (abbreviated as CCD) that performs, for example, monochrome imaging (or monochrome imaging) as an imaging device that captures each image of fluorescence and reflected light. ) 28 is arranged.
As an imaging device for capturing fluorescent and reflected images, a CMD (Charged Modulation Device) imaging device, a C-MOS imaging device, an AMI (Amplified MOS Imager), and a BCCD (Back Illuminated CCD) may be used instead of the CCD 28.

  The excitation light cut filter 27 is a filter that shields excitation light excited to generate fluorescence during fluorescence observation. The characteristics of the excitation light cut filter 27 are shown in FIG. As shown in FIG. 3C, it has a characteristic of transmitting the wavelength band of 470-700 nm, that is, transmitting visible light excluding a part of the wavelength (400-470 nm) of the blue band.

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

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

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

  The CCD 28 is driven by a CCD drive signal from a CCD drive circuit 31 provided in the processor 4A, photoelectrically converts an optical image formed on the CCD 28, and outputs an image signal.

  This image signal is amplified by a preamplifier 32 provided in the processor 4A, further amplified to a predetermined level by an auto gain control (AGC) circuit 33, and then converted from an analog signal to a digital signal (image data) by an A / D conversion circuit 34. 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 that performs switching.

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

  Also in the fluorescence mode, the amount of light received by the CCD 28 during the period of obtaining the fluorescence image by irradiating the excitation light with the E1 filter 22c is larger than that of the reflected light when the illumination is performed with the R1, G1 filters 22a and 22b. Since it is much lower, the electronic shutter function is activated.

  The control circuit 37 controls the moving motor 20 according to the selected mode. The rotation motor 16 is controlled by a 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. The control circuit 37 outputs the output of the encoder. In synchronization, the switching of the CCD drive circuit 31 and the multiplexer 35 is controlled.

  The control circuit 37 controls the switching of the multiplexer 35. In the normal mode, the image data captured under the illumination of the R, G, and B filters 21a, 21b, and 21c are respectively the first frame memory 36a and the second frame memory 36a. Control is performed so that the frame memory 36b and the third frame memory 36c are sequentially stored.

Also in the fluorescence mode, the control circuit 37 controls the switching of the multiplexer 35, and each signal imaged under the illumination of the R1, G1, E1 filters 22a, 22b, and 22c is stored in the first frame memory 36a and the first frame memory 36a, respectively. Control is performed so that the two-frame memory 36b and the third frame memory 36c are sequentially stored.
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 performs normal assignment processing for assigning the input signals to the R, G, and B channel color signals. After image processing for converting the tissue portion and the lesioned tissue portion into an output signal having a hue that can be easily identified, the D / A conversion circuit 39 converts the image into an analog RGB signal and outputs the analog RGB signal.

  In the image processing circuit 38 which is one of the features of the present embodiment, reflected light imaging is performed by using three signals input thereto, that is, reflected light from living tissue by two narrow-band illumination lights G1 and R1. Three signals of the signal and the fluorescence image signal captured by the fluorescence generated from the living tissue by the excitation light E1 are converted by the image processing circuit 38 (appropriately assigned to the color signal for color display) and output. I have to.

The processor 4A is provided with a dimming circuit 40 that automatically controls the opening amount of the light source diaphragm 13 in the light source device 3A based on the signal that has passed through the preamplifier 32. The dimming circuit 40 is controlled by the control circuit 37.
The control circuit 37 controls the lamp current for driving the lamp 12 of the lamp driving circuit 11 to emit light.
The control circuit 37 performs a 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 fluorescence observation filter 22, and the filter of the excitation light cut filter 27 provided in the imaging optical path of the electronic endoscope 2A. The characteristic is that the characteristics are set as shown in FIGS. 3A to 3C so that the degree of separation between the normal tissue and the lesioned tissue can be increased.

  In addition, the image processing circuit 38 appropriately assigns the color signals for color display for the three input signals particularly in the fluorescence mode, thereby making it possible to easily distinguish the normal tissue from the diseased tissue. However, it is also characterized in that it is set so that the lesioned tissue can be displayed 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 intensity distribution with respect to the wavelength of fluorescence obtained from the living tissue, and FIG. 4B shows a characteristic example of intensity distribution with respect to the wavelength of reflected light obtained from the living tissue.

  As can be seen from FIG. 4A, the distribution characteristic having a peak in the vicinity of 520 nm is shown. In this embodiment, the transmission characteristic by the excitation light cut filter 27 is set so as to include the wavelength band near 520 nm. The S / N of the fluorescent image is increased.

Further, in the intensity characteristics of the reflected light in FIG. 4B, the absorption by hemoglobin is large near 550 nm, and the reflection intensity decreases near this wavelength. Note that the vicinity of 600 nm 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 set to 550 nm and 600 nm.

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

Note that the G1 and R1 lights, which are the first and second illumination lights (reflected lights) that are illuminated in the fluorescence mode and imaged with the reflected lights, have a wavelength width set to several tens of nm, more specifically 20 nm. (As will be described later, it may be set to 20 nm or less).
The light transmittance of the blue region (long wavelength region) shielded by the E1 filter 22c and the blue region (short wavelength region) shielded by the excitation light cut filter 27 is OD4 (1/10000) or less. Is set.

  The reason for setting the wavelengths (center wavelengths) at 550 nm and 600 nm in the case of obtaining two reflected light images in the fluorescence mode as described above will be described with reference to FIG.

  FIG. 5 shows a state in which a normal portion and a lesion portion are distributed on axial space coordinates with two reflected light intensities and fluorescence intensities as three axes. In FIG. 5, the portion indicated by the satin pattern is a normal tissue in the living tissue, and the portion indicated by the oblique lines is a lesion tissue in the living tissue.

Since the smaller the portion where the normal tissue and the diseased tissue overlap, the easier it is to distinguish between the normal tissue and the diseased tissue. In this embodiment, two reflected lights are used so that this overlapped portion is minimized. Is calculated using a statistical method (specifically, Fisher's discriminant function).
That is, the separability S is determined by the following equation based on the overlap of the distribution of normal tissue and lesion tissue.

Separability S = 1- (part where the distribution of normal tissue and diseased tissue overlaps) / (whole distribution)
Then, the separation power S obtained is calculated by changing the center wavelengths of the first reflected light and the second reflected light.

  FIG. 6 shows the separability S obtained with respect to the center wavelength of the second reflected light when the center wavelength of the first reflected light is changed as a parameter. Here, a case where the center wavelength of the first reflected light is changed to 510 nm, 550 nm, and 600 nm as a parameter is shown.

  Then, it can be seen that the largest separation S is obtained when the center wavelength of the first reflected light is 550 nm and the center wavelength of the second reflected light is 600 nm. 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. Ability S is obtained.

  FIG. 7 shows the resolution S obtained when the center wavelength of the first reflected light is 550 nm and the wavelength width is changed as a parameter. FIG. 7 shows the case where the wavelength width is 80 nm, 20 nm, and 10 nm.

  It can be seen from FIG. 7 that a large separation S can be obtained when the center wavelength of the first reflected light is about 20 nm or smaller than 550 nm. From FIG. 7, a greater resolution S can be obtained when the wavelength is 10 nm than when 20 nm. However, when the wavelength width is reduced, the strength decreases and the S / N decreases. Therefore, in this embodiment, the wavelength width is set to 20 nm. Depending on the S / N of the signal processing system or the like of the processor 4A, the wavelength width may be set to 20 nm or less, for example, 10 nm.

  From FIG. 6 and FIG. 7, in this 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. It is set to 20 nm so that a large resolution S can be achieved, that is, a normal tissue and a diseased tissue can be distributed as separated as possible.

  In the present embodiment, the intensity of the fluorescent image is much weaker than that of the reflected light. Therefore, as shown in FIG. 4A, a fluorescent image including at least a wavelength band near 520 nm where the intensity reaches a peak is obtained. The excitation light cut filter 27 having the characteristics to be obtained is employed. Thereby, a fluorescent image with good S / N can be obtained.

In the present embodiment, the image processing circuit 38 is set so that the three input signals are appropriately assigned to the three color signals, and the normal tissue and the diseased tissue are easily distinguished from each other on the display image. It is trying to become.
Then, the pseudo color display can be performed in a state where the normal tissue and the diseased tissue are distributed in an easily distinguishable state on the chromaticity diagrams shown in FIGS.

The effect | action of this Embodiment by such a structure is demonstrated 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 4A. Then, the connection state 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. In the initial setting state, for example, the control circuit 37 performs control for setting to operate in the normal mode.

  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 located in the illumination optical path.

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

In this normal mode, the R, G, and B filters 21a, 21b, and 21c are sequentially arranged in the illumination light path for the illumination light (to the observation target side) by the switching filter.
A signal illuminated with R, G, B light and picked up by the CCD 28 is amplified and A / D converted, and then the multiplexer 35 is sequentially switched by the control circuit 37, whereby the first frame memory 36a and the second frame memory 36a The frame memory 36b and the third frame memory 36c are sequentially stored.

  The R, G, and B color component image data stored in the frame memories 36 a to 36 c are simultaneously read out in a predetermined frame period (for example, 33 ms, that is, 1/30 second) and input to the image processing circuit 38. .

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

  In this manner, an analog standard video signal, in this case, an RGB signal, is output to the monitor 5 from the R, G, and B channels through the D / A conversion circuit 39, and is displayed on the display surface of the monitor 5 (white When the light is irradiated, the normal observation image (which reflects the color tone when the subject is directly observed) is displayed in color.

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

In order to prevent this, the control circuit 37 increases the amplification factor of the CCD 28, for example, by a factor of 2 when imaging is performed during the illumination period of the B filter 21c via the CCD drive circuit 31.
Further, the control circuit 37 controls the lamp driving circuit 11 to increase the lamp light amount for driving the lamp 12 during the illumination period of the B filter 21c, for example, from the normal lamp current value, thereby increasing the amount of illumination light for B. .

  The control circuit 37 controls the CCD driving circuit 31 to operate the electronic shutter function of the CCD 28. In other words, during the R and G illumination periods, the CCD 28 is driven so that an image is captured only during a part of the illumination period, and a short imaging period, whereas in the B illumination period, The entire illumination period is used for imaging so that a long imaging period is obtained.

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

  In this way, the subject can be observed in the normal mode. For example, when it is desired to perform fluorescence observation on the subject such as the affected part of interest, the fluorescence mode switch of the mode switch of the scope switch 29 is operated.

  Then, in response to this operation signal, the control circuit 37 sets the state in which the light source device 3A drives the moving motor 20 to move the switching filter 17 so that the fluorescence observation filter 22 is arranged on the illumination optical path. Switch to fluorescence mode.

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

  The subject is sequentially irradiated with light of R1, G1, and E1. In the case of R1 and G1 illumination, the operation is the same as when R and G lights are sequentially emitted in the normal mode. That is, in this case, the CCD 28 receives the reflected light from the R1 and G1 subjects. In this case, the CCD 28 takes an image without being affected by the excitation light cut filter 27.

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

  Since the intensity of this fluorescence is much smaller than the intensity of the reflected light from the R1 and G1 subjects, it is similar to the R, G illumination, B illumination, and signal processing in those cases in the normal mode described above. By performing the operation, a bright fluorescent image (easy to be compared with the image of the reflected light from the R1, G1 subject) is displayed.

  Specifically, when the reflected light from the subjects R1 and G1 is imaged, image data captured by the CCD 28 only during a part of the illumination period is captured by the electronic shutter using the first frame memory 36a and the second frame. The data is stored in the memory 36b.

On the other hand, when the excitation light of E1 is irradiated and the fluorescent image is taken, the amplification factor of the CCD 28 is increased from, for example, about 10 to 100 times, and the lamp current is also increased. It also increases the amount of illumination. In this case, the captured fluorescent image data is stored in the third frame memory 36c.
Then, the image data in the first frame memory 36 a to the third frame memory 36 c are simultaneously read in one frame period and input to the image processing circuit 38.

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

  In the case of the fluorescence mode, the image signal EX having the fluorescence wavelength band is used as the G channel, one of the reflected light wavelength bands having two different center wavelengths and wavelength widths is used as the R channel, and the other reflected light wavelength. The bandwidth is assigned (assigned) to the B channel.

Specifically, an image signal EX having a fluorescence wavelength band is assigned to the G channel, and the signals R1 and G1 of the remaining two reflected light images are assigned to B, R, R, and B. That means
EX → G, R1 → B, G1 → R (assignment 1)
Or EX → G, R1 → B, G1 → R (assignment 2)
It is.

In this case, as shown in FIG. 8 or 9, the normal tissue portion and the lesion tissue portion are different from each other in the chromaticity diagram (corresponding to the chromaticity diagram). 5 is displayed in pseudo color.
In the case of FIG. 8 corresponding to the allocation 1, the lesion tissue portion is limited to the vicinity of the pink hue.

  Further, in the case of FIG. 9 corresponding to the case of allocation 2, the lesion tissue portion is limited to the vicinity of the purple hue. The display modes corresponding to FIG. 8 or FIG. 9 can be switched to each other by operating the switching mode in the fluorescence mode. Then, the user can display it with a favorite one.

Therefore, in the case of FIG. 8, the surgeon can determine that the possibility of a lesion tissue is high by paying attention to the portion displayed near the pink hue.
Further, in the case of FIG. 9, the surgeon can determine that the possibility of a lesion tissue is high by paying attention to a portion displayed near the purple hue.

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

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

  The assignment 3 or the assignment 4 corresponds to a chromaticity diagram as shown in FIG. 10 or FIG. 11 and displays an image in the fluorescence mode, that is, two reflected light images and a fluorescence image in a pseudo color display.

  In FIG. 10 or FIG. 11, since the lesion tissue is displayed so as to be distributed in a plurality of hues, it may not be appropriate when diagnosing a normal tissue and a lesion tissue from the beginning, but FIG. 8 or FIG. When it is diagnosed that the possibility of a diseased tissue is high, if the display mode is further set as shown in FIG. 10 or FIG. 11, the state of the diseased tissue can be more easily diagnosed due to the difference in hue. For example, it becomes easier to determine the degree of progression of a lesion or the like due to a change in hue.

  As described above, according to the present embodiment, when the image by two reflected lights and the fluorescence image are displayed in a pseudo color, the overlap between the normal tissue and the diseased tissue is reduced to increase the resolution S. The wavelength of the reflected light image is set to an appropriate value, and the lesion tissue is displayed in a pseudo color so that it enters a substantially single hue that is easy to distinguish, unlike normal tissue. When diagnosing whether or not, the operator can easily diagnose the diseased tissue. That is, it is possible to provide an environment that facilitates diagnosis.

  Further, the excitation light cut filter 27 disposed 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 performs normal observation. Since light other than a part of the blue light in the visible region is transmitted (a part of the blue light and the entire wavelength band of green and red are transmitted), one image sensor is connected to the insertion portion 7. By disposing at the distal end portion 8, it is possible to display the normal image and the fluorescent image by capturing the normal image, capturing the fluorescent image, and performing signal processing.

  Accordingly, the insertion portion 7 of the electronic endoscope 2A can be made small in diameter (compared with a case where a plurality of imaging elements are incorporated), and the applicable range of insertion can be widened and given to the patient at the time of insertion. Can reduce pain. In addition, the operator can easily insert the body cavity. Further, since only one image sensor is required, the cost can be reduced.

In addition, 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) can be used as the lamp 12 of the light source device 3A. Further, as compared with the case where ultraviolet light or the like is used as the excitation light, there are merits such that the transmission loss due to the light guide fiber 9 can be reduced, or that for normal illumination can be used as it is.
In particular, it is possible to realize an endoscope apparatus 1A that can display an image image in a pseudo color (by a fluorescence image and a reflected light image) so that a normal tissue and a diseased tissue can be easily identified 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 characteristics of the excitation light cut filter 27 shown in FIG. 3C are partially changed.

  FIG. 12 shows the intensity characteristics with respect to the wavelength of fluorescence obtained from a living tissue containing porphyrin. In the case of a living tissue containing porphyrin as shown in this figure, there may be a peak emitting fluorescence due to porphyrin in a wavelength band slightly longer than 620 nm. In order to eliminate the influence of fluorescence due to this polyphyllin, in this embodiment, as shown by a one-dot chain line in FIG. 12, the superwavelength side in the transmission characteristic of the excitation light cut filter 27 is cut at 620 nm, and the longer wavelength than this. The side fluorescence 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 in the first embodiment.

  According to the present embodiment, in addition to the effects of the first embodiment, when observing a living tissue portion containing porphyrin, the influence of porphyrin is excluded and normal tissue and diseased tissue are distinguished. It is possible to provide an endoscope apparatus that can perform pseudo color display with an easy-to-use color tone.

[Appendix]
A light source for generating illumination light for exciting two different wavelength bands and excitation light; and
A light guide means for guiding the illumination light and the excitation light;
Imaging means for capturing two reflected light images by reflected light reflected by the reflected light, and fluorescence images by fluorescence excited by the excitation light.
Image processing means for processing the two reflected light images and the fluorescence image to construct a processed image;
In an endoscope apparatus comprising display means for displaying the processed image,
When plotted on a spatial coordinate axis with three different reflected light and fluorescent intensities from a living tissue as three axes, the wavelengths of the reflected light and the fluorescence are such that normal tissue and diseased tissue are separated on the three-axis spatial coordinate axis. Selected
The reflected light and the fluorescence are assigned to a specific color signal so that the processed image processed by the image processing means has different hues between normal tissue and lesion tissue, and the lesion tissue enters a specific substantially one hue. An endoscope apparatus characterized by being displayed.

1 '. A light source device that generates illumination light of two different wavelength bands and excitation light for exciting fluorescence;
A light guide means for guiding the illumination light and the excitation light;
The living body tissue is irradiated with the illumination light through the light guide means, and each has two reflected light images by the reflected light, and an imaging means for capturing a fluorescence image by the fluorescence excited by the excitation light. An endoscope,
Image processing means for processing the two reflected light images and the fluorescence image to construct a processed image and outputting the processed image to the image display means;
In an endoscope apparatus having
When plotted on a spatial coordinate axis with three different reflected light and fluorescent intensities from a living tissue as three axes, the wavelengths of the reflected light and the fluorescence are such that normal tissue and diseased tissue are separated on the three-axis spatial coordinate axis. Selected
The reflected light and the fluorescence are assigned to a specific color signal so that the processed image processed by the image processing means has different hues between normal tissue and lesion tissue, and the lesion tissue enters a specific substantially one hue. An endoscope apparatus characterized by being displayed.
2. In Supplementary Note 1, two selected reflected light wavelength bands are a wavelength band including an absorption band of hemoglobin light, and the other is a wavelength band including a non-absorption band of hemoglobin light. It is characterized by that.
3. In Supplementary Note 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 Supplementary Note 3, one selected fluorescence wavelength band includes a wavelength band that includes 520 nm and excludes a band of 620 nm or more.

5. In Supplementary Note 3, the wavelength widths of the two selected reflected light wavelength bands are 20 nm to 20 nm or less.
6). In Supplementary Note 1, the processed image includes an image signal from one fluorescent wavelength band in green, one image signal in two reflected light wavelength bands in different wavelength bands in red or blue, and the other in blue Or a red color signal.
7. a light source for illuminating two different wavelength bands of illumination light and excitation light for exciting fluorescence;
The living tissue is irradiated with the illumination light, and each reflected light image is reflected by the reflected light. The illumination light is reflected by the living tissue, and each reflected image is reflected by the reflected light, and the excitation. An imaging means for capturing a fluorescence image by fluorescence excited by light;
Image processing means for processing the two reflected light images and the fluorescence image to construct a processed image;
In an endoscope apparatus comprising display means for displaying the processed image,
The wavelengths of the reflected light and the fluorescence so that the normal tissue and the lesioned tissue are separated on the three-axis spatial coordinate axis when plotted on the spatial coordinate axis with three different reflected light and fluorescence intensities from the living tissue. Is selected,
An endoscopic apparatus, wherein the processed image processed by the processing means is displayed after the reflected light and fluorescence are assigned to a specific color signal so that a diseased tissue spans a plurality of hues.

8. In order to sequentially illuminate the illumination light of two different wavelength bands and the excitation light for exciting fluorescence, the two band filters that pass the wavelength band and the excitation filter that passes the excitation light are arranged to be switchable A light source,
In order to capture the two reflected light images reflected and reflected by the two illumination lights on the living tissue and the fluorescence image by the fluorescence excited by the excitation light, the excitation light is blocked and the fluorescence and reflected light are captured. Imaging means with a built-in fluorescence detection filter that passes through, image processing means for processing the two reflected light images and the fluorescence image to construct a processed image,
In an endoscope apparatus comprising display means for displaying the processed image,
When the wavelength bands of the two band filters and the fluorescence detection filter are plotted on a spatial coordinate axis with the reflected light from two different band filters from the biological tissue and the fluorescence from the fluorescence detection filter as three axes, normal tissue and diseased tissue An endoscope apparatus characterized in that the wavelengths of the band-pass filter and the fluorescence detection filter are selected so as to be separated on a three-axis spatial coordinate axis.

8 '. In order to sequentially illuminate illumination light of two different wavelength bands and excitation light for exciting fluorescence, two band filters that pass the wavelength band and an excitation filter that passes the excitation light are arranged to be switchable. A light source;
In order to capture the two reflected light images reflected and reflected by the two illumination lights on the living tissue and the fluorescence image by the fluorescence excited by the excitation light, the excitation light is blocked and the fluorescence and reflected light are captured. An image capturing means including a fluorescence detection filter that transmits the image, an image processing means 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 means;
In an endoscope apparatus having
When the wavelength bands of the two band filters and the fluorescence detection filter are plotted on a spatial coordinate axis with the reflected light from two different band filters from the biological tissue and the fluorescence from the fluorescence detection filter as three axes, normal tissue and diseased tissue An endoscope apparatus characterized in that the wavelengths of the band-pass filter and the fluorescence detection filter are selected so as to be separated on a three-axis spatial coordinate axis.
9. In Appendix 8, each bandpass filter that limits the wavelength band of the reflected light image to a specific wavelength includes a filter that transmits a wavelength band including an absorption band of hemoglobin light, and a wavelength band that includes a non-absorption band of hemoglobin light. It is a filter which permeate | transmits.
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 that includes 550 nm and a filter that transmits a wavelength band that includes 600 nm. The fluorescence detection filter that limits the band to a specific wavelength is a filter that transmits a wavelength band including 520 nm.

11. Appendix 10 is characterized in that 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.
12 Appendix 10 is characterized in that the fluorescence detection filter that limits the wavelength band of the fluorescence image to a specific wavelength includes 520 nm and has a characteristic of 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 fluorescence, the two band filters that pass the wavelength band and the excitation filter that passes the excitation light are arranged to be switchable A light source,
In order to capture the two reflected light images reflected and reflected by the two illumination lights on the living tissue and the fluorescence image by the fluorescence excited by the excitation light, the excitation light is blocked and the fluorescence and reflected light are captured. Imaging means incorporating a fluorescence detection filter that transmits, image processing means for processing the two reflected light images and the fluorescence image to construct a processed image,
In an endoscope apparatus comprising display means for displaying the processed image,
When the wavelength bands of the two band filters and the fluorescence detection filter are plotted on a spatial coordinate axis with the reflected light from two different band filters from the biological tissue and the fluorescence from the fluorescence detection filter as three axes, normal tissue and diseased tissue The wavelength of the bandpass filter and the fluorescence detection filter are selected so that are separated on the three-axis spatial coordinate axis,
The image processing means includes a processing circuit for assigning the reflected light and the fluorescence to a specific color signal so that the hues of the normal tissue and the diseased tissue are different and the diseased tissue is in a specific color. Endoscopic device characterized.
13 '. In order to sequentially illuminate illumination light of two different wavelength bands and excitation light for exciting fluorescence, two band filters that pass the wavelength band and an excitation filter that passes the excitation light are arranged to be switchable. A light source;
In order to capture the two reflected light images reflected and reflected by the two illumination lights on the living tissue and the fluorescence image by the fluorescence excited by the excitation light, the excitation light is blocked and the fluorescence and reflected light are captured. Imaging means with a built-in fluorescent detection filter, image processing means for processing the two reflected light images and the fluorescence image to construct a processed image and outputting the processed image to the image display means;
In an endoscope apparatus having
When the wavelength bands of the two band filters and the fluorescence detection filter are plotted on a spatial coordinate axis with the reflected light from two different band filters from the biological tissue and the fluorescence from the fluorescence detection filter as three axes, normal tissue and diseased tissue The wavelength of the bandpass filter and the fluorescence detection filter are selected so that are separated on the three-axis spatial coordinate axis,
The image processing means includes a processing circuit for assigning the reflected light and the fluorescence to a specific color signal so that the hues of the normal tissue and the diseased tissue are different and the diseased tissue is in a specific color. Endoscopic device characterized.
14 In Supplementary Note 13, the image processing means is characterized in that the fluorescent image is assigned to the G channel and the reflected light image is assigned to the R channel or B channel color signal.

1 is a block diagram showing an overall configuration of an endoscope apparatus according to a first embodiment of the present invention. The figure which shows the structure of the switching filter provided with the filter for normal observation, and the filter for fluorescence observation. The figure which shows the transmission characteristic with respect to the wavelength of the filter for normal observation, the filter for fluorescence observation, and the excitation light cut filter. The figure which shows the example of a characteristic of intensity distribution with respect to the wavelength of the fluorescence image obtained from a biological tissue, and a reflected light image. The figure which shows a mode that the normal part and the lesion part were plotted and distributed on the axial space coordinate which made fluorescence intensity and two reflected light intensity | strengths 3 axis | shafts. The figure which shows the mode of the change of the separation power with respect to the center wavelength of 2nd reflected light when the wavelength of 1st reflected light is used as a parameter. The figure which shows the mode of the change of the separation power with respect to the center wavelength of 2nd reflected light when the wavelength width of 1st reflected light is used as a parameter. FIG. 6 is a chromaticity diagram showing the distribution of normal and lesion portions obtained when a fluorescent image is assigned to the G channel and the first and second reflected light images are assigned to the B and R channels. The chromaticity diagram showing the distribution of the normal part and the lesion part obtained when the fluorescent image is assigned to the G channel and the first and second reflected light images are assigned to the R and B channels. The figure which shows the chromaticity diagram which shows the distribution of the normal part and lesion part obtained when a fluorescence image is set to B channel and the image of the 1st and 2nd reflected light is set to G and R channel. The figure which shows the chromaticity diagram which shows the distribution of the normal part and lesioned part obtained when a fluorescence image is set to B channel and the image of the 1st and 2nd reflected light is set to R and G channels. The figure which shows the transmission characteristic etc. of the excitation light cut filter in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A ... Endoscope apparatus 2A ... Electronic endoscope 3A ... Light source apparatus 4A ... Processor 5 ... Monitor 7 ... Insertion part 8 ... Tip part 9 ... Light guide fiber 10 ... Connector 11 ... Lamp drive circuit 12 ... Lamp 13 ... Light source aperture DESCRIPTION OF SYMBOLS 14 ... Switching filter part 16 ... Motor for rotation 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
DESCRIPTION OF SYMBOLS 29 ... Scope switch 31 ... CCD drive circuit 34 ... A / D conversion circuit 36a-36c ... Frame memory 37 ... Control circuit 38 ... Image processing circuit

Claims (4)

Illumination light of a plurality of different wavelength bands, a light source that generates excitation light for exciting fluorescence,
Imaging is performed by an imaging unit that captures each reflected light image by reflected light that is irradiated and irradiated with the plurality of illumination light and excitation light from the light source and fluorescence image excited by the excitation light. The reflected light image signal and the fluorescent image signal are input, and an image processing device that performs predetermined image processing;
An endoscopic device comprising:
The image processing apparatus includes an identification unit that identifies a normal tissue and a diseased tissue in a living tissue based on the reflected light image signal and the fluorescence image signal input from the imaging unit,
The illumination light of the plurality of different wavelength bands in the light source is
Based on the intensity distribution characteristic with respect to the wavelength of the reflected light or the fluorescence obtained from the living tissue, the separation power S of the overlap between the distribution of the normal tissue and the distribution of the diseased tissue is determined as the separation power S = 1− (the distribution of the normal tissue and The area where the distribution of the diseased tissue overlaps) / the whole distribution,
An endoscope apparatus characterized by having a wavelength characteristic in which the resolution S used by the identification means has a maximum value.   2. The endoscope according to claim 1, wherein the illumination lights of the plurality of different wavelength bands are set so as to obtain reflected light having a center wavelength of 550 nm and reflected light having a center wavelength of 600 nm. Mirror device.   The endoscope apparatus according to claim 2, wherein the wavelength width of the reflected light is set to 20 nm or less.   The endoscope apparatus according to any one of claims 1 to 3, wherein the excitation light in the light source includes a wavelength band having an intensity peak wavelength of 520 nm.

Images