JP4526322B2 - Endoscope device - Google Patents

Description

  The present invention relates to an endoscope apparatus, and in particular, an image signal of an image of a subject imaged by an imaging unit when a light source device irradiates illumination light, and an imaging unit images when a light source device irradiates excitation light. The present invention relates to an endoscope apparatus that creates a fluorescence observation image using an image signal of an image of a subject.

  Conventionally, endoscope apparatuses have been widely used in the medical field and the like. In particular, an endoscope apparatus in the medical field is mainly used in an application in which an operator performs a treatment such as inspection and observation in a living body as a subject. What is generally known as observation using an endoscope apparatus in the medical field is, for example, that white light is mainly irradiated into a living body, and an in-vivo image that is substantially the same as observation with the naked eye is taken. In addition to normal observation, by capturing an image of autofluorescence emitted from living tissue in the living body when irradiated with excitation light having a specific wavelength band, and observing the autofluorescence image, There are autofluorescence observations that can discriminate between normal and lesion sites. Examples of the endoscope apparatus capable of performing autofluorescence observation include those disclosed in Patent Document 1 and Patent Document 2.

The endoscope apparatuses disclosed in Patent Document 1 and Patent Document 2 both have a light source that illuminates illumination light in two different wavelength bands and excitation light for exciting fluorescence, Illumination light irradiation and imaging means for capturing two reflected light images each of which is reflected by the reflected light, and a fluorescence image by fluorescence excited by the excitation light, the two reflected light images and the fluorescence image And image processing means for constructing a fluorescence observation image which is a processed image. The image processing means included in the endoscope apparatuses disclosed in Patent Document 1 and Patent Document 2 both synchronize the two input reflected light image signals and fluorescent image signals, and R (red ), G (green), and B (blue) channels are appropriately assigned and output, thereby constructing a fluorescence observation image as a processed image. Therefore, both of the endoscope apparatuses disclosed in Patent Document 1 and Patent Document 2 are used when a surgeon performs inspection, observation, and the like on a living body tissue that is a subject. It has a configuration capable of obtaining an image that allows easy identification of a lesion site.
JP 2003-126014 A JP 2003-126015 A

  In general, the intensity of autofluorescence emitted from living tissue when irradiated with excitation light is very weak. Therefore, when the image processing means constructs a fluorescence observation image, it is necessary to devise measures such as increasing the exposure time compared to normal observation. It becomes. In that case, there is a relatively large difference between the time period for the image processing means to construct one fluorescence observation image and the time period for the image processing means to construct one normal observation image. The difference appears as a visual discomfort when performing an examination, observation, or the like on a living tissue in which the surgeon is a subject, in particular, a living tissue affected by the pulsation of the heart. As a result, there is a problem that the difference hinders an operator from performing inspection, observation, and the like on a living body as a subject. However, in the endoscope apparatuses disclosed in Patent Document 1 and Patent Document 2, no means for reducing the difference is described, and no proposal for the above problem has been made.

  The present invention has been made in view of the above-described points, and after constructing a fluorescence observation image that allows an operator to sufficiently distinguish between a normal site and a lesion site of a living tissue, an image processing unit includes: The difference between the time period for constructing one fluorescence observation image and the time period for the image processing means to construct one normal observation image is reduced, and the operator is in the living body as the subject. It is an object of the present invention to provide an endoscope apparatus that can reduce visual discomfort during inspection, observation, and the like.

An endoscope apparatus according to the present invention includes a light source having means for sequentially irradiating illumination light having a predetermined wavelength band and excitation light for exciting fluorescence of a subject periodically in a predetermined time period. The object is imaged through a filter having a characteristic of transmitting light on a longer wavelength side than the excitation light without transmitting the excitation light, and the image captured when the light source device irradiates the illumination light. Imaging means for converting a reflected image of the subject into a first image signal, and converting the fluorescence image of the subject taken when the light source device irradiates the excitation light into a second image signal and outputting the second image signal; Three image signal recording means configured to be able to temporarily record the first image signal and the second image signal, and among the first image signal and the second image signal, One image signal of the three image signals Any two of the recording means are simultaneously input to the image signal recording means, and the other image signal of the first image signal and the second image signal is input to the three image signal recording means. Control for performing control for outputting the image signals input to the three image signal recording means in synchronization with each other in the predetermined time period after being input to the remaining one of the image signal recording means. means, red by performing predetermined signal processing on the image signal output is more synchronized with the control of said control means, green and blue three color signals corresponding to the luminance component to produce respectively, Of the signals corresponding to the luminance components of the three colors, the luminance levels of the signals corresponding to the luminance components of the other two colors are respectively corrected with reference to the luminance level of the signal corresponding to the luminance component of any one color. Out Includes an image processing unit that, the.

  In the endoscope apparatus according to the present invention, the image processing means constructs one fluorescence observation image after constructing a fluorescence observation image that allows the operator to sufficiently distinguish between a normal site and a lesion site of a living tissue. The difference between the time required for the image processing and the time required for the image processing means to construct one normal observation image is reduced, and the vision when the surgeon performs inspection, observation, etc. on the living body as the subject. The feeling of discomfort can be reduced.

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

  FIG. 1 is a diagram illustrating an overall configuration of an endoscope apparatus according to the present embodiment. FIG. 2 is a diagram illustrating spectral characteristics of the excitation light cut filter included in the endoscope apparatus according to the present embodiment. FIG. 3 is a diagram illustrating a configuration of a switching filter included in the endoscope apparatus according to the present embodiment. FIG. 4 is a diagram illustrating spectral characteristics of the R filter, the G filter, and the B filter provided in the switching filter included in the endoscope apparatus according to the present embodiment. FIG. 5 is a diagram illustrating spectral characteristics of the E1 filter and the G1 filter provided in the switching filter included in the endoscope apparatus according to the present embodiment. FIG. 6 is a block diagram illustrating a configuration of an image processing circuit included in the endoscope apparatus according to the present embodiment. FIG. 7 is a timing chart showing the timing of synchronization of the R signal, the G signal, and the B signal when performing normal observation in the endoscope apparatus according to the present embodiment. FIG. 8 is a timing chart showing the synchronization timing of the AF signal and the Ga signal when performing fluorescence observation in the endoscope apparatus according to the present embodiment. FIG. 9 is a diagram illustrating an example of a fluorescence observation image constructed when fluorescence observation is performed in the endoscope apparatus according to the present embodiment. FIG. 10 is a diagram illustrating an overall configuration of a modified example of the endoscope apparatus according to the present embodiment. FIG. 11 is a diagram illustrating spectral characteristics of an excitation light cut filter included in an endoscope apparatus according to a modification of the present embodiment. FIG. 12 is a diagram illustrating a configuration of a switching filter included in an endoscope apparatus according to a modification example of the present embodiment. FIG. 13 is a diagram illustrating spectral characteristics of the E2 filter and the G2 filter provided in the switching filter included in the endoscope apparatus according to the modification of the present embodiment. FIG. 14 is a timing chart showing the synchronization timing of the AF signal and the Ga signal when performing fluorescence observation in the endoscope apparatus according to the modification of the present embodiment.

  As shown in FIG. 1, an endoscope apparatus 1A according to the present embodiment irradiates an endoscope 2A that is partially inserted into a living body, which is a subject, and light used when the subject is observed. 3A, a processor 4A that performs processing for constructing a normal observation image and a fluorescence observation image, and a monitor 5 that displays the normal observation image and the fluorescence observation image constructed by the processor 4A in color.

  The endoscope 2A includes an insertion portion 7 and a distal end portion 8 having an outer diameter that can be inserted into a body cavity, an illumination lens 24 that is provided inside the distal end portion 8 and diffuses light emitted from the light source device 3A. An objective lens system 25 provided inside the tip 8 for connecting an optical image of the subject, and provided inside the tip 8, and the amount of incident light is spatially adjusted to focus from a far point to a near point. A diaphragm 26 to be limited, an excitation light cut filter 27 provided inside the distal end portion 8 for cutting the excitation light, a CCD (Charge Coupled Device) 28 serving as an imaging device provided inside the distal end portion 8, The scope switch 29 includes a scope ID generation unit 41 in which unique ID information including at least the model of the endoscope 2A is recorded.

  As shown in FIG. 2, the excitation light cut filter 27 is a filter having a characteristic of transmitting light having a wavelength band of 470 to 700 nm, and is irradiated during fluorescence observation in order to generate autofluorescence in a living tissue. Excitation light is shielded, and light having a longer wavelength than the excitation light is transmitted.

The CCD 28 which is an imaging means is driven by a CCD drive signal output from a CCD drive circuit 31 provided in the processor 4A, images the subject, converts the captured subject image into an image signal, and converts the image to the processor 4A. The scope switch 29 that outputs to the preamplifier 32 provided in FIG. 1 has one or a plurality of input interfaces (not shown), for example, an observation mode changeover switch for switching between normal observation and fluorescence observation, and the CCD 28 takes an image. An interface such as a release switch, which is an instruction for recording the image signal of the image of the subject as a still image, is provided. When the operator operates the interface such as the observation mode switch described above, an operation signal based on the operation is output to the control circuit 37 provided in the processor 4A, and based on the operation signal, the control circuit 37 Each part of the mirror device 1A is controlled.

  When the endoscope 2A is connected to the processor 4A, the scope ID generation unit 41 outputs ID information of the connected endoscope 2A to the model detection circuit 42 provided in the processor 4A.

  Further, a light guide fiber 9 made of quartz fiber or the like for guiding light emitted from the light source device 3A is inserted into the insertion portion 7. One end of the light guide fiber 9 has a light source connector 10 that is detachably connected to the light source device 3 </ b> A, and the other end of the light guide fiber 9 is the distal end portion 8 of the insertion portion 7. It is arrange | positioned in the vicinity of the illumination lens 24 provided in.

  The light source device 3 </ b> A is provided on the irradiation path of the lamp 12, the lamp driving circuit 11, the lamp 12 that is driven to emit light by the lamp driving circuit 11, and irradiates light including the visible light band from the infrared wavelength band. A light source diaphragm 13 for limiting the amount of light emitted from the lamp 12, a switching filter unit 14 provided on the irradiation light path of the lamp 12, and a condenser lens 15 for condensing the light that has passed through the switching filter unit 14. is doing.

  The switching filter unit 14 includes a switching filter 17, a rotation motor 16 for rotationally driving the switching filter 17, a rack 18 attached to the rotation motor 16, and a pinion attached to be screwed into the rack 18. 19 and a motor 20 for moving the switching filter 17 in a direction perpendicular to the axis of the irradiation light path of the lamp 12 by rotationally driving the pinion 19.

  The rotation motor 16 has an encoder (not shown) attached to a rotating shaft or the like, and the encoder converts information on the driving state of the switching filter 17 into a driving state signal. The driving state signal is output to the control circuit 37 of the processor 4A.

  As shown in FIG. 3, the switching filter 17 has a normal observation RGB filter 21 on the inner peripheral portion and a fluorescence observation filter 22 on the outer peripheral portion. Further, the RGB filter 21 and the fluorescence observation filter 22 are arranged so as to be concentric in the switching filter 17, and when the operator operates the observation mode switch of the scope switch 29, based on the contents of the operation, When the moving motor 20 is driven via the control circuit 37 of the processor 4A and the RGB filter 21 is arranged on the irradiation light path of the lamp 12, normal observation can be performed, and the fluorescence observation filter 22 is provided as a lamp. When arranged on 12 irradiation light paths, it has a configuration capable of performing fluorescence observation.

  The RGB filter 21 includes an R filter 21a that transmits light having a red wavelength band, a G filter 21b that transmits light having a green wavelength band, and a blue filter, which are provided so as to divide the circumferential direction into approximately three equal parts. And a B filter 21c that transmits light having a wavelength band of three, and when the rotary motor 16 is driven to rotate, the three filters are inserted sequentially and substantially continuously on the irradiation light path of the lamp 12. It has a configuration. Further, as shown in FIG. 4, the R filter 21a transmits light having a wavelength band of 600 to 700 nm, the G filter 21b transmits light having a wavelength band of 500 to 600 nm, and the B filter 21c is It has a filter characteristic that transmits light having a wavelength band of 400-500 nm.

  The fluorescence observation filter 22 includes an E1 filter 22a that transmits a narrow-band excitation light and a G1 filter 22b that transmits light having a narrow green wavelength band. When the rotary motor 16 is rotationally driven, the two filters are sequentially and substantially continuously inserted on the irradiation light path of the lamp 12. Further, as shown in FIG. 5, the E1 filter 22a transmits light having a wavelength band of 395 to 445 nm, and the G1 filter 22b has a filter characteristic of transmitting light having a wavelength band of 540 to 560 nm. The filter characteristics of the G1 filter 22b are not limited to those described above. For example, it is sufficient if the G1 filter 22b has a characteristic that transmits light having a wavelength band including 550 nm and a full width at half maximum of less than 50 nm. .

  The processor 4A includes a CCD drive circuit 31, a preamplifier 32, an AGC (auto gain control) circuit 33, an A / D (analog / digital) conversion circuit 34, a first frame memory 36a, and a second frame memory 36b. A third frame memory 36c, a multiplexer 35, a control circuit 37, an image processing circuit 38 as image processing means, a D / A (digital / analog) conversion circuit 39, a dimming circuit 40, and a model detection circuit. 42 and a setting switch 43.

  The image signal output from the CCD 28 is amplified by the preamplifier 32, further amplified to a predetermined level by the AGC circuit 33, and then converted from an analog signal to a digital signal by the A / D conversion circuit 34. Then, the image signal converted into the digital signal passes through a multiplexer 35 for switching the recording destination of the image signal, and the first frame memory 36a, the second frame memory 36b and the third frame memory 36c which are image signal recording means. Is temporarily recorded. The image signals recorded in the first frame memory 36a, the second frame memory 36b, and the third frame memory 36c are synchronized in a predetermined time period, and then input to the image processing circuit 38 for predetermined signal processing. . The image signal on which the predetermined signal processing has been performed is converted from a digital signal to an analog signal by the D / A conversion circuit 39 and then output to the monitor 5.

  The CCD drive circuit 31 is controlled by the control circuit 37. The CCD drive circuit 31 controls the CCD 28 to adjust the amount of light received by the CCD 28 by operating an electronic shutter function, for example, during normal observation and fluorescence observation.

  The control circuit 37 controls the CCD drive circuit 31, the multiplexer 35, and the like based on the drive state signal output from the encoder of the rotation motor 16.

  The control circuit 37 controls the multiplexer 35 to switch the image signal recording destination output from the CCD 28. In the case of normal observation, the control circuit 37 outputs image signals of the subject image captured by the CCD 28 under illumination light irradiated through the R filter 21a, the G filter 21b, and the B filter 21c. The multiplexer 35 is controlled so as to be sequentially stored in the 1-frame memory 36a, the second-frame memory 36b, and the third-frame memory 36c. Further, in the case of fluorescence observation, the control circuit 37 outputs the image signal of the subject image captured by the CCD 28 in the first frame under the illumination light irradiated through the E1 filter 22a and the G1 filter 22b. The multiplexer 35 is controlled so as to be sequentially stored in the memory 36a, the second frame memory 36b, and the third frame memory 36c. That is, in the control circuit 37, one image signal is input to two frame memories of the first frame memory 36a, the second frame memory 36b, and the third frame memory 36c, and the other image signal is input to one frame memory. Control that is input is performed on the multiplexer 35.

  The control circuit 37 controls the lamp driving circuit 11 and adjusts the amount of light emitted from the lamp 12.

  The image processing circuit 38 performs a process such as a matrix conversion process on the three image signals input in a synchronized state in the first frame memory 36a, the second frame memory 36b, and the third frame memory 36c. The performed image signal is output as a first signal, a second signal, and a third signal. The first signal, the second signal, and the third signal are assigned to the three channels R, G, and B, respectively, when performing color display on the monitor 5 that is a display means. Is a signal having the following luminance component. In the fluorescence observation, the normal part and the lesion part in the living body in the display image of the monitor 5 depending on the combination of the image signals input to the first frame memory 36a, the second frame memory 36b, and the third frame memory 36c. The color tone changes. Details of the change in the color tone will be described later.

  The light control circuit 40 is controlled by the control circuit 37, and adjusts the opening amount of the light source diaphragm 13 provided in the light source device based on the control content.

  The model detection circuit 42 detects the model information of the endoscope 2A connected based on the ID information of the endoscope 2A output from the scope ID generation unit 41, and outputs the model information to the control circuit 37. To do.

  The setting switch 43 is connected to the image processing circuit 38 and can set parameters and the like when the matrix circuit 45 performs matrix conversion processing.

  Next, a specific configuration of the image processing circuit 38 will be described with reference to FIG.

  The image processing circuit 38 includes a matrix circuit 45, range correction tables 46a, 46b and 46c for correcting the luminance level of the signal output from the matrix circuit 45, a parameter determining unit 47 for determining parameters in the matrix circuit 45, ROM (Read Only Memory) 48.

  The matrix circuit 45 is inputted to the three input terminals Ta, Tb, and Tc of the image processing circuit 38 from the first frame memory 36a, the second frame memory 36b, and the third frame memory 36c when fluorescence observation is performed. Each image signal is subjected to matrix conversion processing, which is predetermined signal processing, and each image signal after the processing is output as a first signal, a second signal, and a third signal.

  The range correction tables 46a, 46b, and 46c correct the luminance levels of the first signal, the second signal, and the third signal output from the matrix circuit 45 when fluorescence observation is performed, and perform the correction. The first to third signals that have been performed are output from the three output terminals Ta1, Tb1, and Tc1 of the image processing circuit 38 to the D / A conversion circuit 39.

  The parameter determination unit 47 determines a parameter in matrix conversion processing in accordance with a control signal output from the control circuit 37 based on the model information of the endoscope 2A, and outputs the parameter to the matrix circuit 45.

  The ROM 48 stores one or more parameters in the matrix conversion process. For example, when the surgeon operates the setting switch 43 to select and set a parameter stored in the ROM 48, the ROM 48 outputs the parameter to the parameter determination unit 47. When the parameter determination unit 47 detects that a parameter is output from the ROM 48, the parameter determination unit 47 invalidates the parameter determined according to the control signal output from the control circuit 37 based on the model information of the endoscope 2A. In addition, the parameter output from the ROM 48 is validated and output to the matrix circuit 45.

  Next, the operation when using the endoscope apparatus 1A of the present embodiment having the above-described configuration will be described.

  When using the endoscope apparatus 1A, the surgeon connects the light source connector 10 of the endoscope 2A to the light source apparatus 3A as shown in FIG. Connect the connector to the processor 4A. Then, after the connection state as shown in FIG. 1 is set, the power of each device (not shown) is turned on to set the operation state. When the power of each device is turned on, the control circuit 37 controls and sets each device as an initial setting so that, for example, normal observation can be performed. As a setting for performing normal observation, the control circuit 37 sets the movement motor 20 of the light source device 3 </ b> A so that the RGB filter 21 provided on the inner periphery of the switching filter 17 is arranged on the irradiation light path of the lamp 12. Control.

  When observation is started by the operator operating the scope switch 29 or the like, the control circuit 37 performs control for driving the rotation motor 16 to rotate. The light irradiated from the lamp 12 is transmitted through the light having the red wavelength band by the R filter 21a, the G filter 21b, and the B filter 21c of the RGB filter 21 being inserted on the irradiation light path of the lamp 12. R) light, green (G) light that transmits light having a green wavelength band, and blue (B) light that transmits light having a blue wavelength band, and are split through light guide fibers 9, respectively. For example, the subject is irradiated sequentially and substantially continuously in a period of 1/20 second.

  At each timing when red, green, and blue light is irradiated to the subject, the CCD 28 takes an image of the subject, and the reflected images of the subject are taken as a red image signal and a green image signal, respectively. And converted into a blue image signal and output to the processor 4A. The red image signal, green image signal, and blue image signal output to the processor 4A are amplified and A / D converted in each part of the processor 4A, and then recorded by switching control of the multiplexer 35 by the control circuit 37. The destinations are sequentially switched and recorded in the first frame memory 36a, the second frame memory 36b, and the third frame memory 36c, respectively. As shown in FIG. 7, a red image signal (R1, R2,... In FIG. 7) and a green image signal (G0 in FIG. 7) recorded in the first frame memory 36a, the second frame memory 36b, and the third frame memory 36c. , G1,...) And the blue image signal (B0, B1,... In FIG. 7) are synchronized with a period of 1/20 second and output to the image processing circuit 38, for example. The image processing circuit 38 does not perform processing such as matrix conversion processing during normal observation, and outputs each input image signal to the D / A conversion circuit 39 as it is. Each image signal output from the image processing circuit 38 is converted into an RGB signal which is an analog standard video signal in the D / A conversion circuit 39 and is output to the monitor 5 from the R, G and B channels. The monitor 5 displays the normal observation image in color based on the RGB signals.

  In addition, when performing fluorescence observation, the operator first operates the observation mode switch of the scope switch 29. When the scope switch 29 is operated by the operator, an operation signal based on the content of the operation is output to the control circuit 37. The control circuit 37 that has detected the operation signal sets the light source so that the fluorescence observation filter 22 provided on the outer periphery of the switching filter 17 is arranged on the irradiation light path of the lamp 12 as a setting for performing fluorescence observation. The moving motor 20 of the apparatus 3A is controlled.

  When the observation is started, the control circuit 37 performs control for driving the rotary motor 16 to rotate. The light emitted from the lamp 12 fluoresces the living tissue in the living body as the subject by inserting the E1 filter 22a and the G1 filter 22b of the fluorescence observation filter 22 into the irradiation light path of the lamp 12. The light is split into excitation light for excitation and illumination light having a wavelength band including at least 550 nm, and each light is transmitted through the light guide fiber 9 at a predetermined time period of, for example, 1/15 second. The subject is irradiated sequentially and substantially continuously.

  At the timing when the illumination light is applied to the subject, the CCD 28 captures a reflected image of the subject in the same way as in normal observation, and the captured reflected image of the subject is the first image signal. It converts into an illumination light image signal and outputs it to the processor 4A. On the other hand, at the timing when the excitation light is irradiated to the subject, the reflected light of the excitation light E1 is substantially completely shielded by the excitation light cut filter 27, and the living tissue is excited by the excitation light cut filter 27. In order to emit fluorescence having a wavelength band of the transmission band, the CCD 28 captures a fluorescence image of the subject by the received fluorescence, and the captured fluorescence image of the subject is converted into a fluorescence image as a second image signal. The signal is converted into a signal and output to the processor 4A. The illumination light image signal and the fluorescence image signal output to the processor 4A are amplified and A / D converted in each part of the processor 4A, and then the recording destination is sequentially controlled by switching control of the multiplexer 35 by the control circuit 37. Can be switched.

  The multiplexer 35 records one image signal of the illumination light image signal and the fluorescence image signal in any two of the first frame memory 36a, the second frame memory 36b, and the third frame memory 36c. In addition, the recording destination of each video signal is sequentially switched so that the other image signal other than one of the image signals is recorded in one frame memory other than the two frame memories. Do. For example, the multiplexer 35 switches the recording destination of each video signal such as recording the illumination light image signal in the first frame memory 36a and the third frame memory 36c and recording the fluorescent image signal in the second frame memory 36b. I do. Then, as shown in FIG. 8, the illumination light image signals (Ga1, Ga2,... In FIG. 8) recorded in the first frame memory 36a and the third frame memory 36c and the fluorescent image recorded in the second frame memory 36b. The signals (AF1, AF2,... In FIG. 8) are synchronized in a period of 1/15 seconds, which is a predetermined time period, and are output to the image processing circuit 38, for example.

  When the illumination light image signal is recorded in the first frame memory 36a and the third frame memory 36c and the fluorescence image signal is recorded in the second frame memory 36b, the matrix circuit 45 of the image processing circuit 38 performs predetermined signal processing. By performing a certain matrix conversion process, the illumination light image signal output from the first frame memory 36a is converted into a first signal, and the fluorescent image signal output from the second frame memory 36b is converted into a second signal. Then, the illumination light image signal output from the third frame memory 36c is converted into a third signal. Then, the first signal, the second signal, and the third signal after the matrix conversion process are output to the range correction tables 46a, 46b, and 46c, respectively. The range correction tables 46a, 46b, and 46c are displayed when the fluorescence observation image is displayed on the monitor 5 with respect to the first signal, the second signal, and the third signal output from the matrix circuit 45. The brightness level is corrected so that the surgeon can sufficiently recognize the normal site and the lesion site due to the difference in color tone. Specifically, the range correction tables 46a, 46b, and 46c are: (luminance level of the first signal): (luminance level of the second signal): (luminance level of the third signal) = 1: x: y And the luminance levels of the first signal, the second signal, and the third signal are such that x and y satisfy 0.5 ≦ x ≦ 3.5 and y ≧ 0. Perform the correction. Note that the range correction tables 46a, 46b, and 46c are based on the ratio of the luminance levels of the first to third signals described above, assuming that the luminance level value of the first signal is A (A is an arbitrary real number). Are output from the three output terminals Ta1, Tb1, and Tc1 of the image processing circuit 38 as the luminance level value A, the second signal as the luminance level value xA, and the third signal as the luminance level value yA, respectively. The first to third signals output from the range correction tables 46a, 46b and 46c, which are predetermined image signals, are converted into analog RGB signals which are video signals by the D / A conversion circuit 39, and R, G And output from the B channel to the monitor 5. Then, the monitor 5 displays the fluorescence observation image in a pseudo color display as shown in FIG. 9 based on the RGB signals. Specifically, the lesion area 101a is displayed on the monitor 5 as magenta, the normal area 101b is green, and the blood vessel 101c is black. That is, the processor 4A of the endoscope apparatus 1A can construct a fluorescence observation image that is displayed in a pseudo color on the monitor 5 from the two types of input image signals.

As shown in Table 1 below, the color tone of the fluorescence observation image displayed on the monitor 5 is the illumination light image signal and fluorescence input to the first frame memory 36a, the second frame memory 36b, and the third frame memory 36c. It relates to a combination of image signals and a combination of signals output from the R, G and B channels.

  In the description of the present embodiment, the case of No. 1 in Table 1 has been particularly described. However, the endoscope apparatus 1A of the present embodiment has, for example, combinations of Nos. 2 to 6 in Table 1. It is also possible to display the fluorescence observation image on the monitor 5 with a color tone. Furthermore, the endoscope apparatus 1A of the present embodiment does not output signals from all three channels R, G, and B, for example, a fluorescent image signal is output from one channel, and an illumination light image Even when the signal is output from only one of the other two channels other than the one channel, the fluorescence observation image can be constructed and displayed on the monitor 5. Regarding the luminance level correction performed by the range correction tables 46a, 46b, and 46c, the ratios and conditions of the luminance levels of the first to third signals described above are suitable only for the first case in Table 1. And conditions.

  In addition, as shown in FIG. 10, an endoscope apparatus 1B as a modification of the present embodiment includes an endoscope 2B having two CCDs, a fluorescence observation CCD 28a and a normal observation CCD 28b. The light source device 3B and the processor 4A are connected to each other. In the description of FIG. 1 to FIG. 9 of the present embodiment, the following description will be made while omitting a part of the portions having the same configuration and operation.

  The endoscope 2B includes an insertion portion 7 and a distal end portion 8, an illumination lens 24 provided inside the distal end portion 8, a scope switch 29, a scope ID generating portion 41, and a changeover switch 64. In addition, the endoscope 2B is a fluorescence observation that includes an objective lens system 25a, a first diaphragm 26a, an excitation light cut filter 27a, and a fluorescence observation CCD 28a that is an image pickup device, which are provided inside the distal end portion 8. And a normal observation imaging unit including an objective lens system 25b, a second diaphragm 26b, and a normal observation CCD 28b provided inside the distal end portion 8.

  As shown in FIG. 11, the excitation light cut filter 27a is a filter having a characteristic of transmitting light having a wavelength band of 490 to 630 nm, and is irradiated during fluorescence observation in order to generate autofluorescence in a living tissue. Excitation light is shielded, and light having a longer wavelength than the excitation light is transmitted.

  The fluorescence observation CCD 28 a and the normal observation CCD 28 b are connected to the CCD drive circuit 31 and the preamplifier 32 via the changeover switch 64.

  When the setting for performing fluorescence observation is performed by operating the scope switch 29, the changeover switch 64 is configured to select and use the fluorescence observation imaging unit having the fluorescence observation CCD 28a and perform normal observation. Is switched based on the operation content of the scope switch 29 and the control content of the control circuit 37 so that the normal observation imaging unit having the normal observation CCD 28b is selected and used. It has a configuration.

  Further, the light source device 3B in the modification of the present embodiment includes a switching filter unit 14a, and the switching filter unit 14a is provided with a switching filter 17a. The light source device 3B has the same configuration as that of the light source device 3A described above except for the switching filter 17a.

  As shown in FIG. 12, the switching filter 17a has an RGB filter 21 for normal observation on the inner periphery and a fluorescence observation filter 22A on the outer periphery. Further, the RGB filter 21 and the fluorescence observation filter 22A are arranged so as to be concentric in the switching filter 17, and when the operator operates the observation mode switch of the scope switch 29, based on the contents of the operation, When the moving motor 20 is driven via the control circuit 37 of the processor 4A and the RGB filter 21 is arranged on the irradiation light path of the lamp 12, normal observation can be performed, and the fluorescence observation filter 22A is used as the lamp. When arranged on 12 irradiation light paths, it has a configuration capable of performing fluorescence observation.

  The fluorescence observation filter 22A is provided in the circumferential direction and has an E2 filter 22c that transmits a narrow-band excitation light having a shape as shown in FIG. 12, and is provided in the circumferential direction and has a shape as shown in FIG. And a G2 filter 22d that transmits light having a narrow green wavelength band. When the G2 filter 22d is driven to rotate by the rotary motor 16, the two filters are sequentially and substantially continuously provided on the irradiation light path of the lamp 12. It is configured to be inserted. As shown in FIG. 13, the E1 filter 22c transmits light having a wavelength band of 395 to 475 nm, and the G1 filter 22d has a filter characteristic of transmitting light having a wavelength band of 540 to 560 nm.

  When performing fluorescence observation using the endoscope apparatus 1B of the present modification having the above-described configuration, first, the operator operates the observation mode changeover switch of the scope switch 29. When the scope switch 29 is operated by the operator, an operation signal based on the content of the operation is output to the control circuit 37. The control circuit 37 that has detected the operation signal sets the light source so that the fluorescence observation filter 22 provided on the outer periphery of the switching filter 17 is arranged on the irradiation light path of the lamp 12 as a setting for performing fluorescence observation. The moving motor 20 of the apparatus 3A is controlled.

  When the observation is started, the control circuit 37 performs control for driving the rotary motor 16 to rotate. The light emitted from the lamp 12 fluoresces the living tissue in the living body as the subject by inserting the E2 filter 22c and the G2 filter 22d of the fluorescence observation filter 22A on the irradiation light path of the lamp 12. The light is split into excitation light for excitation and illumination light having a wavelength band including at least 550 nm, and each light is sequentially and substantially continuously via a light guide fiber 9 in a period of 1/20 second, for example. The object is irradiated.

  The illumination light image signal and the fluorescence image signal captured and converted by the CCD 28 and output to the processor 4A are amplified and A / D converted in each part of the processor 4A, and then the multiplexer 35 is switched by the control circuit 37. The recording destination is sequentially switched by the control. The multiplexer 35 records one image signal of the illumination light image signal and the fluorescence image signal in any two of the first frame memory 36a, the second frame memory 36b, and the third frame memory 36c. In addition, the recording destination of each video signal is sequentially switched so that the other image signal other than one of the image signals is recorded in one frame memory other than the two frame memories. Do. For example, the multiplexer 35 switches the recording destination of each video signal such as recording the illumination light image signal in the first frame memory 36a and the third frame memory 36c and recording the fluorescent image signal in the second frame memory 36b. I do. Then, as shown in FIG. 14, the illumination light image signals (Ga1, Ga2,... In FIG. 14) recorded in the first frame memory 36a and the third frame memory 36c and the fluorescent image recorded in the second frame memory 36b. The signals (AF1, AF2,... In FIG. 14) are synchronized with a period of 1/20 second, for example, and output to the image processing circuit 38. Thereafter, the illumination light image signal and the fluorescence image signal are subjected to processing such as matrix conversion processing similar to the above-described content in the image processing circuit 38, and then analog RGB as video signals by the D / A conversion circuit 39. The signal is converted into a signal and output to the monitor 5 from the R, G, and B channels. The color tone of the fluorescence observation image output to the monitor 5 is substantially the same as the color tone of the image shown in FIG.

  The endoscope apparatus 1A according to the present invention monitors a normal site and a lesion site of a living tissue when at least one illumination light image signal and one fluorescence image signal are input to the processor 4A. A fluorescence observation image that can be sufficiently distinguished by the operator can be constructed by the difference in color tone in the fluorescence observation image displayed in FIG. Therefore, the time period for synchronizing and outputting each image signal can be shortened compared with the conventional case where illumination light of two different wavelength bands is used. As a result, the difference between the time for the processor 4A to construct one fluorescence observation image and the time for the processor 4A to construct one normal observation image can be reduced, and the operator is the subject. It is possible to reduce visual discomfort when performing inspection, observation, etc. on the living body.

  Further, the processor 4A of the endoscope apparatus 1A of the present invention can construct a fluorescence observation image if at least one illumination light image signal and one fluorescence image signal are input. Therefore, the fluorescence observation filter 22 of the light source device 3A only needs to have at least two types of filters. As a result, in the light source device used when constructing the fluorescence observation image, the fluorescence observation image is constructed by using a cheaper light source device as compared with the conventional light source device having at least three types of filters. Therefore, it is possible to reduce manufacturing costs when manufacturing a light source device used in fluorescence observation.

  Further, in the endoscope apparatus 1B as a modification of the embodiment of the present invention, the rotation time periods of the RGB filter 21 and the fluorescence observation filter 22A are the same. Therefore, the time required for the processor 4A to construct one fluorescence observation image and the time required for the processor 4A to construct one normal observation image can be made substantially the same. As a result, the endoscope apparatus 1B can further reduce the visual discomfort when the operator performs inspection, observation, and the like on the living body that is the subject as compared with the endoscope apparatus 1A.

The figure which shows the whole structure of the endoscope apparatus which concerns on this embodiment. The figure which shows the spectral characteristic of the excitation light cut filter which the endoscope apparatus which concerns on this embodiment has. The figure which shows the structure of the switching filter which the endoscope apparatus which concerns on this embodiment has. The figure which shows the spectral characteristics of R filter, G filter, and B filter provided in the switching filter which the endoscope apparatus which concerns on this embodiment has. The figure which shows the spectral characteristics of the E1 filter and G1 filter which were provided in the switching filter which the endoscope apparatus which concerns on this embodiment has. The block diagram which shows the structure of the image processing circuit which the endoscope apparatus which concerns on this embodiment has. The timing chart which shows the timing of a synchronization with R signal, G signal, and B signal at the time of performing normal observation in the endoscope apparatus which concerns on this embodiment. The timing chart which shows the timing of the synchronization of AF signal and Ga signal at the time of performing fluorescence observation in the endoscope apparatus which concerns on this embodiment. The figure which shows the example of the fluorescence observation image constructed | assembled when performing fluorescence observation in the endoscope apparatus which concerns on this embodiment. The figure which shows the whole structure of the modification of the endoscope apparatus which concerns on this embodiment. The figure which shows the spectral characteristic of the excitation light cut filter which the endoscope apparatus which concerns on the modification of this embodiment has. The figure which shows the structure of the switching filter which the endoscope apparatus which concerns on the modification of this embodiment has. The figure which shows the spectral characteristic of the E2 filter and G2 filter which were provided in the switching filter which the endoscope apparatus which concerns on the modification of this embodiment has. The timing chart which shows the timing of the synchronization of AF signal and Ga signal at the time of performing fluorescence observation in the endoscope apparatus which concerns on the modification of this embodiment.

Explanation of symbols

1A, 1B Endoscope device, 2A, 2B Endoscope, 3A, 3B Light source device, 4A Processor, 5 Monitor, 7 Insertion part, 8 Tip part, 9 Light guide fiber, 10 Light source connector, 11 Lamp drive circuit, 12 lamp, 13 light source aperture, 14, 14a switching filter, 15 condenser lens, 16 rotation motor, 17, 17a switching filter, 18 rack, 19 pinion, 20 moving motor, 21 RGB filter, 21a R filter, 21b G Filter, 21c B filter, 22, 22A Fluorescence observation filter, 22a E1 filter, 22b G1 filter, 22c E2 filter, 22d G2 filter, 24 Illumination lens, 25, 25a, 25b Objective lens system, 26 Aperture, 26a First aperture , 26b Second diaphragm, 27, 27a Excitation light cut filter 28 CCD, 28a CCD for fluorescence observation, 28b CCD for normal observation, 29 scope switch, 31 CCD drive circuit, 32 preamplifier, 33 AGC circuit, 34 A / D conversion circuit, 35 multiplexer, 36a first frame memory, 36b first 2 frame memory, 36c 3rd frame memory, 37 control circuit, 38 image processing circuit, 39 D / A conversion circuit, 40 dimming circuit, 41 scope ID generator, 42 model detection circuit, 43 setting switch, 45 matrix circuit, 46a, 46b, 46c Range correction table, 47 parameter determination unit, 48 ROM, 64 changeover switch, 101a lesion site, 101b normal site, 101c vascular agent patent attorney Susumu Ito

Claims (4)

A light source device having means for sequentially irradiating illumination light having a predetermined wavelength band and excitation light for exciting fluorescence to the subject periodically in a predetermined time period;
The object is imaged through a filter having a characteristic of transmitting light having a wavelength longer than the excitation light without transmitting the excitation light, and the object imaged when the light source device irradiates the illumination light. Imaging means for converting a reflected image into a first image signal, converting the fluorescent image of the subject imaged when the light source device irradiates the excitation light into a second image signal, and outputting the second image signal;
Three image signal recording means configured to be able to temporarily record the first image signal and the second image signal;
One image signal of the first image signal and the second image signal is simultaneously input to any two of the three image signal recording means, and the first image signal is recorded. The other image signal of the second image signal and the second image signal are input to the remaining one of the three image signal recording means, and then the three image signal recordings are performed. Control means for performing control for synchronizing and outputting each image signal input to the means in the predetermined time period;
Red by performing predetermined signal processing on a more synchronized with the image signal outputted to the control of said control means, green and blue three color signals corresponding to the luminance component to produce respectively, the three colors An image to be output after correcting the luminance levels of the signals corresponding to the luminance components of the other two colors with reference to the luminance level of the signal corresponding to the luminance component of any one of the signals corresponding to the luminance components of Processing means;
An endoscope apparatus characterized by comprising:   The endoscope apparatus according to claim 1, wherein the predetermined wavelength band of the illumination light is a wavelength band including 550 nm.   The endoscope apparatus according to claim 1, wherein the predetermined wavelength band includes 550 nm, and a full width at half maximum is less than 50 nm. Wherein the image processing means, the ratio of the luminance level of the fluorescence observation image displayed on the Viewing means, (red luminance level) :( green luminance level) :( blue luminance level) = 1: x: y becomes In addition, the luminance levels of the signals corresponding to the luminance components of the three colors are corrected and output so that x and y satisfy 0.5 ≦ x ≦ 3.5 and y ≧ 0 , respectively. The endoscope apparatus according to any one of claims 1 to 3.

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