JP2012125331A - Endoscope system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a good special light image corresponding to a photographic condition (near view observation and distant view observation).SOLUTION: In a special light observation mode of an endoscope system, a rotational filter 32 for the special light observation is arranged on an optical path of a broad band region light BB emitted from a broad band region light source 30. A filter area 39 for near view observation inserted into the optical path in the near view observation and a filter area 40 for the distance view observation inserted in the light path in the distance view observation are provided in a concentric circle in the rotational filter 32 for the special light observation. In the filter area 39 for the near view observation, by making the area of a filter 41B for a first B narrow band region light larger than the area of a filter 41G for a first G narrow band region, it results in the B emitting time>the G emitting time, and the blood vessel in the surface layer is emphasized. In the filter area 40 for the distance view observation, by making the area of the filter 42G for the second G narrow band region light larger than the area of the filter 42B for the second B narrow band region light, it results in the G emitting time>the B emitting time, and the mucous membrane or the like in the bessel is more brightly displayed.

Description

  The present invention relates to an endoscope system that performs special light observation using light of two types of specific wavelengths.

  In recent years, endoscope systems that perform so-called special light observation, such as irradiating a living tissue with a specific narrow wavelength band (narrowband light) to obtain an observation image in which blood vessels in the living tissue are emphasized, are known ( For example, see Patent Document 1). Since the light absorption spectrum of blood vessels (hemoglobin) has an absorption peak in a band near 415 nm or 540 nm, these endoscope systems have a wavelength in a band with a high light absorption rate near 415 nm as narrowband light. The blue (B) narrowband light and the green (G) narrowband light having a wavelength in the band having a high light absorption rate near 540 nm are used as illumination light.

  When narrow-band light corresponding to a band where the light absorption rate of the blood vessel is high is used, in the observation image, the blood vessel part is dark because light is absorbed, and it is bright because it is scattered and reflected without being absorbed by the surrounding tissue. It is reflected. By narrowing the illumination light, the wavelength outside the band with high light absorptance is removed from the illumination light, so that the components scattered and reflected in the blood vessel portion are reduced, and the contrast between the blood vessel and the surrounding tissue is enhanced. An observed image can be obtained.

  Moreover, since the light scattering characteristics in the living tissue become lower as the wavelength becomes longer, the light having a longer wavelength reaches the deeper layer of the living tissue (the degree of penetration is higher). Therefore, by using two types of narrowband light, B narrowband light and longer wavelength G narrowband light, an image that emphasizes the surface blood vessels in the surface layer near the surface of the living tissue is obtained by the B narrowband light. Thus, it is possible to obtain an image in which deeper mid-deep blood vessels are emphasized by the G narrow band light.

  An endoscope system described in Patent Literature 1 includes a white light source and a rotary filter provided with two types of bandpass filters that respectively transmit B narrowband light and G narrowband light. By rotating the, the time-sequential imaging that images two types of narrow-band light observation images in a time-division manner with an image sensor in accordance with the timing when two types of band-pass filters are alternately inserted into the optical path of the white light source The method is adopted. In the frame sequential method, an observation image in which both the surface layer and the middle-deep blood vessel are emphasized is displayed on the monitor by combining the two observed images.

Japanese Patent Laid-Open No. 2001-170009

  At the time of special light observation, the imaging condition including the distance between the endoscope distal end and the blood vessel changes in particular by moving the endoscope distal end incorporating the image sensor. As a result, the blood vessel detection ability and the brightness of the observation image change. For example, in the case of distant view observation in which the distal end of the endoscope is observed at a position away from the blood vessel in contrast to the near view observation in which the distal end of the endoscope is located close to the blood vessel, the light amount is insufficient. The whole will be dark. As a result, there arises a problem that it is difficult to observe the observation image.

  There is a method to deal with such a problem by signal processing such as increasing the gain of the signal output of the image pickup device. However, if the gain is increased, the noise increases, so when the signal output is small, the S / N is remarkably high. descend. In narrow-band light observation, imaging is performed with a small amount of light as compared with normal observation using white light, so that the signal output is often small. Therefore, it is difficult to adopt a method that deals with signal processing.

  In the special light observation, the observation target is not necessarily the same in the near view observation and the distant view observation. For example, when observing a distant view, observe the overall state of the observed site, including the positional relationship between the superficial blood vessels and the middle-deep blood vessels, and conversely, when observing a close-up view, focus on the superficial blood vessels that tend to cause lesions due to early cancer. There is. In such a case, the wavelength band of the narrow band light required for the near view observation and the distant view observation is different, but the endoscope system of Patent Document 1 emits light according to the photographing conditions such as the near view observation and the distant view observation. Since narrow-band light cannot be changed, a good observation image is not always obtained.

  The present invention has been made to solve the above-described problem, and an object thereof is to provide an area-sequential endoscope system capable of obtaining a good observation image according to photographing conditions such as foreground observation and distant view observation. To do.

  In order to achieve the above object, an endoscope system according to the present invention includes a narrowband light source that repeatedly emits first and second narrowband lights having different wavelength bands used for special light observation in a predetermined order, and the first Imaging means for obtaining an observation image of the observed site by imaging the observed site irradiated with the first and second narrowband lights, and a first of the first narrowband light emitted from the narrowband light source Light source control means for controlling the emission time and the second emission time of the second narrowband light.

  Based on the observation image obtained by the imaging means, the imaging condition detection means for detecting a predetermined imaging condition at the time of acquisition is provided, and the light source control means is responsive to the imaging condition detected by the imaging condition detection means. It is preferable to change the first and second emission times.

  The second narrow-band light has a wavelength band longer than the wavelength band of the first narrow-band light, and the imaging condition detection unit includes a distal end portion of an endoscope as the imaging condition. It is detected whether the object is in a near-field observation state where the distance to the observation site is close or a distant-view observation state where the distance is far, and the light source control means is configured so that the imaging condition detection means The first emission time is longer than the second emission time when a state is detected, and the second emission time is longer than the first emission time when the distant view observation state is detected. Preferably, the narrow band light source is controlled.

  The narrowband light source transmits a broadband light source that emits white broadband light, a first filter that transmits the first narrowband light of the broadband light, and transmits the second narrowband light of the broadband light. A substantially annular filter area having a second filter is provided concentrically for each of the photographing conditions around a rotation axis, and each of the filter areas is moved by moving the rotary filter in the radial direction. Filter area inserting means for selectively inserting any of the above into the optical path of the broadband light, and filter rotating means for rotating the rotary filter around the rotation axis, The ratio of the areas of the first to second filters in the filter area matches the ratio of the first to second emission times determined in advance for each imaging condition. It is preferably set Te.

  It is preferable that the light source control unit controls the filter area insertion unit so that the filter area corresponding to the imaging condition detected by the imaging condition detection unit is inserted into the optical path.

  The rotary filter includes a first narrowband optical priority filter area formed such that an area of the first filter is larger than an area of the second filter, and an area of the second filter is larger than an area of the first filter. It is preferable to have a second narrowband light priority filter area formed.

  The light source control means, based on the imaging conditions detected by the imaging condition detection means, according to the first to second emission time preset values set in the imaging conditions, the first to second narrowband lights. It is preferable to control the narrow-band light source so that each is emitted.

  The narrowband light source includes a broadband light source that emits white broadband light, a first filter that is disposed in an optical path of the broadband light, and transmits the first narrowband light of the broadband light, and the broadband light A rotation filter having a second filter that transmits the second narrowband light; and a filter rotation unit that rotates the rotation filter and alternately inserts the first filter and the second filter into the optical path. And the light source control means controls the filter rotation means so that the insertion times for inserting the first and second filters into the optical path are equal to the set values of the first and second emission times, respectively. It is preferable to do.

  The filter rotating means intermittently rotates the rotary filter so that the first filter and the second filter are each temporarily inserted in the optical path of the broadband light, and the first to first filters It is preferable that the time for each of the two filters to pause in the optical path is equal to the set value of the first to second emission times.

  The first and second narrowband lights are light used for highlighting blood vessels in the living tissue, and blue narrowband light having a wavelength corresponding to the absorption peak of the absorption spectrum of hemoglobin light, green Narrow band light is preferred.

  Since the endoscope system of the present invention controls the first emission time of the first narrowband light and the second emission time of the second narrowband light that are repeatedly emitted from the narrowband light source in a predetermined order. Depending on various shooting conditions such as near view observation and distant view observation, it is possible to lengthen the emission time of the first and second emission times suitable for the shooting conditions. Thereby, a favorable observation image according to the photographing conditions can be obtained.

It is a perspective view of the endoscope system of a 1st embodiment. It is the block diagram which showed the electric constitution of the endoscope system of 1st Embodiment. It is sectional drawing of the rotation filter for normal observation. It is sectional drawing of the rotation filter for special light observation. It is a flowchart for demonstrating the flow of a process of special light observation. It is explanatory drawing for demonstrating the imaging process of CCD in (A) normal observation mode, (B) near view observation mode, and (C) distant view observation mode. It is explanatory drawing which showed an example of the foreground special light image. It is explanatory drawing which showed an example of the special light image for distant views. It is sectional drawing of the integrated rotation filter which is other embodiment of the rotation filter for special light observation of FIG. It is the block diagram which showed the electric constitution of the endoscope system of 2nd Embodiment. It is a flowchart for demonstrating the flow of the process of special light observation of 2nd Embodiment. It is explanatory drawing for demonstrating the imaging process of CCD in (A) normal observation mode and near view observation mode of 2nd Embodiment, and (B) distant view observation mode. It is sectional drawing of the integrated rotation filter which is other embodiment of the rotation filter for special light observation shown in FIG. It is sectional drawing of the rotation filter for special light observation of other embodiment which has a filter area for distant view observation different from the rotation filter for special light observation of FIG.

[First Embodiment]
As shown in FIG. 1, an endoscope system 10 includes an electronic endoscope 11 that captures an inside of a patient's digestive tract and trachea (observed site), and an imaging signal obtained by the electronic endoscope 11. Are provided with a processor device 12 for generating an observation image in the tube, a light source device 13 for supplying illumination light for irradiating the inside of the tube to the electronic endoscope 11, and a monitor 14 for displaying the observation image.

  In the endoscope system 10, a normal observation mode in which the inside of the tube is entirely observed by illuminating the inside of the tube with broadband light such as white light, and a state in which the inside of the tube is illuminated with narrowband light and the surface blood vessels are highlighted. There are two observation modes: a special light observation mode for observation. The special light observation mode includes a near-field observation mode in which observation is performed in a close-up state where the distance between the distal end portion of the electronic endoscope 11 and the living tissue in the tube is short, and observation is performed in a distant state where the distance from the living tissue is long. There are two observation modes, a distant view observation mode to be performed.

  The electronic endoscope 11 is connected to a flexible insertion portion 16 to be inserted into a tube and a proximal end portion of the insertion portion 16, and is used for gripping the electronic endoscope 11 and operating the insertion portion 16. And a universal cord 18 for connecting the operation unit 17 to the processor device 12 and the light source device 13, respectively.

  The insertion portion distal end portion 16a that is the distal end portion of the insertion portion 16 incorporates an optical system, an image sensor, and the like that are used for illumination inside the tube and photographing. Further, in addition to the observation window 19 (see FIG. 2) and the illumination window 20 (see FIG. 2), an air / water supply nozzle, which is not shown, is inserted into the distal end surface of the insertion portion distal end portion 16a. A forceps outlet or the like serving as an outlet of the forceps channel is provided. A bendable bending portion 16b is connected to the rear end of the insertion portion distal end portion 16a.

  The operation unit 17 is provided with an angle knob 21, an operation button 22, a forceps inlet 23, and the like. The angle knob 21 is rotated when adjusting the bending direction and the bending amount of the insertion portion 16. The operation button 22 is used for various operations such as air / water supply and suction. The forceps inlet 23 communicates with the forceps channel.

  The universal cord 18 incorporates an air / water channel, a signal cable, a light guide, and the like. A connector portion 25 a is provided at the distal end portion of the universal cord 18. This connector portion 25 a is connected to the light source device 13. Further, the connector part 25b branches from the connector part 25a. This connector portion 25 b is connected to the processor device 12.

  As shown in FIG. 2, the light source device 13 includes a broadband light source 30, a normal observation rotary filter 31 used in the normal observation mode, a special light observation rotary filter 32 used in the special light observation mode, and a filter. A shift mechanism (filter area inserting means) 33, a filter rotating mechanism (filter rotating means) 34, and a condenser lens 35 are provided.

  The broadband light source 30 is, for example, a xenon lamp, a white LED, a micro white light source, or the like, and generates white broadband light BB having a wavelength ranging from a red region to a blue region (about 470 to 700 nm). The broadband light source 30 always emits broadband light BB during endoscopic examination.

  A part of the normal observation rotary filter 31 is inserted into the optical path of the broadband light BB emitted from the broadband light source 30 in the normal observation mode. A part of the special light observation rotary filter 32 is inserted into the optical path of the broadband light BB in the special light observation mode.

  As shown in FIG. 3, the normal observation rotary filter 31 includes a blue filter 37B, a green filter 37G, and a red filter 37R provided along the circumferential direction of the rotary shaft 31a. The areas of the color filters 37B, 37G, and 37R are all formed to have the same size. The blue filter 37B transmits blue band light (B light) out of the broadband light BB. The green filter 37G transmits green band light (G light) out of the broadband light BB. The red filter 37R transmits red band light (R light) out of the broadband light BB.

  The color filters 37B, 37G, and 37R are rotated in the normal observation mode by rotating the normal observation rotation filter 31, so that the color filters 37B, 37G, and 37R have a predetermined order (for example, blue, green, red, blue,...) In the optical path of the broadband light BB. Is inserted repeatedly. Thereby, B light, G light, R light, B light,... Are emitted in order from the normal observation rotary filter 31.

  As shown in FIG. 4, the special light observation rotary filter 32 transmits narrowband light in two specific wavelength bands predetermined in the special light observation mode out of the broadband light BB incident from the broadband light source 30. Let These two types of narrowband light were restricted to a narrowband light (hereinafter referred to as “B narrowband light”, a first narrowband light) Bn limited to a specific wavelength band of blue and a specific wavelength band of green. Narrow-band light (hereinafter referred to as G narrow-band light, second narrow-band light) Gn.

  The wavelength band of the B narrowband light Bn is adjusted according to the absorption peak (for example, around 415 nm) of the absorption spectrum of the hemoglobin light. Moreover, from the knowledge about the light scattering characteristics of the living tissue, if the wavelength of the irradiated light does not exceed about 470 nm, most of the irradiated light is absorbed by the surface blood vessel and does not return to the insertion portion distal end portion 16a. On the contrary, in the living tissue around the superficial blood vessel, most of the irradiated light is reflected by the relatively strong scattering characteristics and returns to the insertion portion distal end portion 16a. As a result, the contrast between the superficial blood vessel and the surrounding biological tissue becomes extremely high, so that the superficial blood vessel and the like can be sufficiently highlighted.

  The wavelength band of the G narrow band light Gn is adjusted in accordance with the absorption peak (for example, around 540 nm) of the absorption spectrum of the hemoglobin light. In addition, based on the knowledge about the light scattering characteristics of biological tissue, the light reaches the mid-deep blood vessels deeper than the surface blood vessels when the wavelength of the irradiated light is in the vicinity of 500 nm to 600 nm. While this light is absorbed by the middle-deep blood vessel, it is reflected and scattered by the living tissue around the middle-deep blood vessel. As a result, the contrast between the mid-deep blood vessel and the surrounding biological tissue is increased, so that the mid-deep blood vessel and the like can be sufficiently highlighted.

  The special light observation rotary filter 32 includes two types of substantially annular foreground observation filter areas (first narrow-band light priority filter areas) 39 and a distant view observation filter area from the central rotation axis 32a outward. (Second narrowband light priority filter area) 40 is provided concentrically.

  The foreground viewing filter area 39 is inserted into the optical path of the broadband light BB in the foreground viewing mode. The foreground viewing filter area 39 includes a first blue (B) narrowband light filter (first filter) 41B and a first green (G) narrowband light filter provided along the circumferential direction of the rotation shaft 32a. (Second filter) 41G.

  The first B narrowband light filter 41B transmits the B narrowband light Bn out of the broadband light BB. The first G narrowband light filter 41G transmits the G narrowband light Gn in the broadband light BB. The area of the first B narrowband light filter 41B is formed to be larger than the area of the first G narrowband light filter 41G.

  Each of the narrowband light filters 41B and 41G has an optical path of the broadband light BB in the optical path of the broadband light BB by rotating the special light observation rotary filter 32 in a state where the foreground observation filter area 39 is inserted in the optical path of the broadband light BB. Are repeatedly inserted in a predetermined order (for example, blue, green, blue, green,...). Thus, the B narrowband light Bn, the G narrowband light Gn, the B narrowband light Bn,... Are alternately and repeatedly emitted from the special light observation rotary filter 32.

  In the foreground viewing filter area 39, the area of the first B narrowband light filter 41B is formed larger than the area of the first G narrowband light filter 41G, and therefore the emission time of the B narrowband light Bn (hereinafter referred to as B). The emission time) is longer than the emission time of the G narrowband light Gn (hereinafter referred to as G emission time). Thus, the B emission time and the G emission time are determined according to the ratio of the areas of the first B narrowband light filter 41B and the first G narrowband light filter 41G.

  The ratio of the area of the first B narrowband light filter 41B to the area of the first G narrowband light filter 41G is the ratio of the B emission time and the G emission time predetermined in the foreground observation mode (B emission time> G emission time). In the present embodiment, the ratio of the areas of the two narrowband light filters 41B and 41G is set to 2: 1, for example.

  The distant view observation filter area 40 is inserted into the optical path of the broadband light BB in the distant view observation mode. The distant view observation filter area 40 includes a second blue (B) narrowband light filter (first filter) 42B and a second green (G) narrowband light filter provided along the circumferential direction of the rotation shaft 32a. And a filter (second filter) 42G.

  The second B narrowband light filter 42B has the same light transmission characteristics as the first B narrowband light filter 41B, and transmits the B narrowband light Bn in the broadband light BB. The second G narrowband light filter 42G has the same light transmission characteristics as the first G narrowband light filter 41G, and transmits the G narrowband light Gn in the broadband light BB. The area of the second B narrowband light filter 42B is smaller than the area of the second G narrowband light filter 42G.

  Each color narrow band light filter 42B, 42G has the optical path of the broadband light BB rotated by the rotation of the special light observation rotary filter 32 in a state where the distant view observation filter area 40 is inserted in the optical path of the broadband light BB. Are repeatedly inserted in a predetermined order. Thus, the B narrowband light Bn, the G narrowband light Gn, the B narrowband light Bn,... Are alternately and repeatedly emitted from the special light observation rotary filter 32.

  In the distant view observation filter area 40, the area of the second G narrowband light filter 42G is formed larger than the area of the second B narrowband light filter area 42B, so that the G emission time becomes longer than the B emission time. . The ratio of the areas of the two narrowband light filters 41B and 41G is set in accordance with the ratio of the B emission time and the G emission time (B emission time <G emission time) predetermined in the distant view observation mode. In the present embodiment, the ratio of the areas of the two narrowband light filters 41B and 41G is set to, for example, 1: 2.

  Returning to FIG. 2, the filter shift mechanism 33 moves the normal observation rotary filter 31 and the special light observation rotary filter 32 in directions substantially perpendicular to the optical path of the broadband light BB. The filter shift mechanism 33 is configured so that the normal observation rotary filter 31 is inserted into the optical path of the broadband light BB and any of the color filters 37B, 37G, and 37R is inserted, and all the color filters 37B, 37G, and 37R are in the optical path. Move between the retracted position retracted from the inside. The filter shift mechanism 33 moves the normal observation rotary filter 31 to the insertion position in the normal observation mode, and moves the normal observation rotary filter 31 to the retracted position in the special light observation mode.

  Further, the filter shift mechanism 33 includes the special light observation rotary filter 32, the near view observation filter area 39 is inserted into the optical path of the broadband light BB, and the far view observation filter area 40 is a broadband light. The distant view observation insertion position inserted into the optical path of BB and the both filter areas 39, 40 are moved between the retracted positions retracted from the optical path of the broadband light BB. The filter shift mechanism 33 moves the special light observation rotary filter 32 to the retracted position in the normal observation mode, moves the special light observation rotary filter 32 to the near view observation insertion position in the near view observation mode, and special light in the far view observation mode. The observation rotation filter 32 is moved to the distant view observation insertion position.

  The filter rotation mechanism 34 is connected to the respective rotation shafts 31 a and 32 a of the normal observation rotation filter 31 and the special light observation rotation filter 32. The filter rotation mechanism 34 rotates the normal observation rotation filter 31 at a constant speed in the normal observation mode, and rotates the special light observation rotation filter 32 at a constant speed in the special light observation mode.

  The rotational speeds of the rotary filters 31 and 32 are set so as to rotate once in an imaging period of, for example, 3 frames. As a result, an imaging period of one frame is assigned to each of the B light, G light, and R light transmitted through the normal observation rotary filter 31. On the other hand, the B narrowband light Bn and the G narrowband light Gn that pass through the foreground viewing filter area 39 of the special light observation rotary filter 32 are each assigned an imaging period of two frames and one frame. The B narrowband light Bn and the G narrowband light Gn that pass through the distant view observation filter area 40 are assigned an imaging period of one frame and two frames, respectively.

  The condenser lens 35 is an optical path of B light, G light, and R light emitted from the normal observation rotation filter 31 in the normal observation mode, and is emitted from the special light observation rotation filter 32 in the special light observation mode. It is arranged on the optical path of the G narrow band light Gn and the B narrow band light Bn. The condenser lens 35 causes each incident illumination light to enter the light guide 43.

  With each configuration described above, the light source device 13 repeatedly emits B light, G light, and R light to the light guide 43 in the normal observation mode. Further, the light source device 13 repeatedly emits the B narrowband light Bn and the G narrowband light Gn having different emission times to the light guide 43 according to the near view observation mode and the far view observation mode of the special light observation mode.

  The electronic endoscope 11 includes a light guide 43, a CCD type image sensor (hereinafter referred to as “CCD” imaging unit) 44, an analog processing circuit (AFE: Analog Front End) 45, and an imaging control unit 46. The light guide 43 is a large-diameter optical fiber, a bundle fiber, or the like. The light guide 43 has an incident end inserted into the light source device 13 and an emission end opposed to an irradiation lens 48 provided in the insertion portion distal end portion 16a. The illumination light incident on the irradiation lens 48 from the light guide 43 is irradiated into the tube through the illumination window 20. Then, the light reflected in the tube enters the condenser lens 51 through the observation window 19.

  The CCD 44 has an imaging surface 44 a in which a plurality of photodiodes (not shown) are two-dimensionally arranged. The CCD 44 converts subject light incident from the condenser lens 51 into an electrical imaging signal and outputs it to the AFE 45. . The CCD 44 is a monochrome CCD having a predetermined spectral sensitivity. A MOS type image sensor may be used instead of the CCD. An imaging control unit 46 controlled by the processor device 12 is connected to the CCD 44.

  The imaging control unit 46 is connected to a CPU in the processor device 12 and sends a drive signal to the CCD 44 based on a command from the CPU. The CCD 44 outputs an imaging signal to the AFE 45 at a predetermined frame rate based on the drive signal from the imaging control unit 46. In the normal observation mode, in accordance with the rotation of the normal observation rotary filter 31, a step of outputting a blue image signal by storing, reading, and transferring signal charges by photoelectric conversion of B light, and a step of outputting signal charges by photoelectric conversion of G light A step of outputting a green image signal by accumulation / reading / transfer and a step of outputting a red image signal by accumulation / reading / transfer of signal charges by photoelectric conversion of R light are repeatedly executed.

  In the special light observation mode, blue narrow band imaging is performed by accumulating / reading / transferring signal charges by photoelectric conversion of the B narrow band light Bn according to the type of the observation mode and the rotation of the special light observation rotary filter 32. A step of outputting a signal and a step of outputting a green narrowband imaging signal by accumulation, readout and transfer of signal charges by photoelectric conversion of the G narrowband light Gn are repeatedly executed.

  Although not shown, the AFE 45 includes a correlated double sampling circuit (CDS), an automatic gain control circuit (AGC), and an analog / digital converter (A / D). The CDS performs correlated double sampling processing on the imaging signal from the CCD 44 to remove noise. The AGC amplifies the imaging signal from which noise has been removed by CDS. The A / D converts the image pickup signal amplified by the AGC into a digital image pickup signal having a predetermined number of bits and sends it to the processor device 12.

  The processor device 12 includes a CPU (light source control means) 54, a digital signal processor (DSP) 55, a frame memory 56, an observation state determination unit 57, a display control circuit 58, and an observation mode switch. 59. The CPU 54 is connected to each part of the processor device 12, the imaging control unit 46 of the electronic endoscope 11, the filter shift mechanism 33 and the filter rotation mechanism 34 of the light source device 13 through signal lines, and comprehensively controls them. .

  The DSP 55 performs signal processing such as white balance adjustment, color tone processing, gradation processing, and sharpness processing on the imaging signal input from the AFE 45. In the normal observation mode, the DSP 55 performs the above-described signal processing on the blue image pickup signal, the green image pickup signal, and the red image pickup signal that are sequentially input from the AFE 45, thereby generating normal image data of three colors B, G, and R. The normal image data is stored in the frame memory 56.

  On the other hand, when the observation mode is set to the foreground observation mode, the DSP 55 appropriately performs signal processing on each of the blue narrow-band imaging signal and the green narrow-band imaging signal sequentially input from the AFE 45, thereby Two-color near-field special light image data including a narrowband image and a green narrowband image is generated. In addition, when the observation mode is set to the distant view observation mode, the DSP 55 applies signal processing to each of the two narrow-band imaging signals sequentially input from the AFE 45, thereby similarly for two colors of distant views. Generate special light image data. These foreground special light image data and distant view special light image data are also stored in the frame memory 56.

  The observation state determination unit 57 detects the exposure amount on the basis of the luminance signal of one of the near-field special light image data and the far-field special light image data newly stored in the frame memory 56. The observation state determination unit 57 determines that the current state is in the near view observation state when the exposure amount is equal to or greater than a certain value, and indicates that the subject is in the distant view observation state when the exposure amount is less than the certain value. judge. This determination result is sequentially input to the CPU 54.

  When the observation mode is the normal observation mode, the display control circuit 58 reads the normal image data of the three colors from the frame memory 56 and displays the observation image obtained by synthesizing the normal images of the three colors on the monitor 14. When the composite normal image is displayed on the monitor 14, B, G, and R normal images are assigned to the B channel, G channel, and R channel of the monitor 14, respectively, and output.

  Further, when the observation mode is the special light observation mode, the display control circuit 58 reads the special light image data of the two colors from the frame memory 56, and monitors the observation image obtained by synthesizing the special light images of the two colors. To display. When displaying this observation image, the blue narrow-band image is assigned to the B and G channels of the monitor 14, and the green narrow-band image is assigned to the R channel of the monitor 14. In the surface blood vessel portion of the observation image displayed on the monitor 14, the B and G channels become dark because the pixel value of the blue narrow band image is close to “0” due to the absorption of the B narrow band light Bn, and only the R channel. Appears relatively brown because it is relatively bright. Further, since the R channel becomes dark due to the absorption of the G narrow band light Gn, the middle-deep blood vessel portion is displayed in cyan mixed with the B and G channels.

  The observation mode switch 59 is operated when switching the observation mode of the endoscope system 10 to the normal observation mode or the special light observation mode.

  When the normal observation mode is selected by the observation mode switch 59, the CPU 54 sets the observation mode to the normal observation mode. Further, when the special light observation mode is selected by the observation mode changeover switch 59, the CPU 54 sets the observation mode to the near view observation mode or the distant view observation mode based on the determination result of the observation state determination unit 57. Then, the CPU 54 controls the filter shift mechanism 33 and the filter rotation mechanism 34 according to the set type of observation mode, and switches the type of illumination light emitted from the light source device 13.

  Further, the CPU 54 functions as an insertion filter determination unit 54a that determines the type of filter inserted on the optical path of the broadband light BB at the time of endoscopy. The insertion filter discriminating unit 54a is provided in any one of the color filters 37B, 37G, and 37R in the normal observation mode, the rotation speed of the normal observation rotary filter 31, the area and shape of the color filters 37B, 37G, and 37R, and the color filters 37B, 37G, and 37R. Based on the result of reading a reference marker (not shown) with a reader (not shown), it is determined which of the color filters 37B, 37G, 37R is inserted in the optical path of the broadband light BB.

  On the other hand, in the near-field observation mode, the insertion filter discriminating unit 54a rotates the rotation speed of the special light observation rotary filter 32, the area and shape of each of the narrowband light filters 41B and 41G, and each narrowband light filter 41B, Based on the reading result of the reference marker provided in any of 41G, it is determined which of the narrowband light filters 41B and 41G is inserted in the optical path of the broadband light BB. The insertion filter determination unit 54a also determines which of the narrowband light filters 42B and 42G is inserted on the optical path of the broadband light BB in the same manner even in the distant view observation mode. The CPU 54 drives the CCD 44 by controlling the imaging control unit 46 based on the discrimination result of the insertion filter discrimination unit 54a.

  Next, the operation of the endoscope system 10 having the above configuration will be described using the flowchart shown in FIG. When the power of the processor device 12 and the light source device 13 is turned on and an endoscopic inspection preparation process (hereinafter referred to as an inspection preparation process) is performed, driving of the CCD 44 is started and broadband light from the broadband light source 30 is started. BB emission is started. The endoscope system 10 is set to the normal observation mode in the initial state when the power is turned on.

  The CPU 54 controls the filter shift mechanism 33 during the inspection preparation process to move the normal observation rotation filter 31 and the special light observation rotation filter 32 to the insertion position and the retraction position, respectively. Next, the CPU 54 controls the filter rotating mechanism 34 to rotate the normal observation rotating filter 31 at a constant speed. Thereby, B light, G light, and R light are repeatedly emitted from the normal observation rotary filter 31 toward the condenser lens 35.

  When the examination preparation process is completed, the insertion portion 16 of the electronic endoscope 11 is inserted into a patient's digestive tract, trachea, or other tube. The B light, G light, and R light individually incident on the condenser lens 35 are irradiated into the patient's tube through the light guide 43, the irradiation lens 48, and the illumination window 20, respectively. Thereby, the B light, G light, and R light reflected / scattered in the tube enter the observation window 19 and enter the CCD 44 through the condenser lens 51.

  At this time, the insertion filter determination unit 54a determines which of the color filters 37B, 37G, and 37R is inserted in the optical path of the broadband light BB based on the rotation speed of the normal observation rotary filter 31 and the like. Based on the determination result, the CPU 54 controls the imaging control unit 46 to send a drive signal to the CCD 44.

  As shown in FIG. 6A, since the ratio of the areas of the color filters 37B, 37G, and 37R is 1: 1: 1, the CCD 44 performs one frame while the normal observation rotary filter 31 rotates by 1/3. During the imaging period, the B light is photoelectrically converted and a blue image signal is output to the AFE 45. Next, the CCD 44 photoelectrically converts the G light and outputs a green image signal to the AFE 45 during the imaging period of one frame while the normal observation rotary filter 31 further rotates by 1/3. Then, the CCD 44 photoelectrically converts R light and outputs a red image signal to the AFE 45 during an imaging period of one frame while the normal observation rotary filter 31 further rotates by 1/3. Similarly, the CCD 44 repeatedly outputs each color image signal according to the rotation of the normal observation rotary filter 31.

  The AFE 45 performs various signal processing on the image pickup signal from the CCD 44 and sequentially outputs a digital blue image pickup signal, a green image pickup signal, and a red image pickup signal to the DSP 55 of the processor device 12. Each color image signal is subjected to various signal processing by the DSP 55 and then stored in the frame memory 56 as normal image data of three colors. The display control circuit 58 reads each normal image data newly stored in the frame memory 56 under the control of the CPU 54, and causes the monitor 14 to display a normal observation image based on each normal image data.

  Hereinafter, until the observation mode is switched to the special light observation mode, or until the endoscopic examination is completed, the acquisition of the normal image data and the monitor display of the normal image are repeatedly executed.

  Returning to FIG. 5, when switching from normal observation to special light observation, the observation mode switch 59 is switched to the special light observation mode. In the special light observation mode, the foreground observation mode is set as an initial setting. The CPU 54 issues a filter switching command to the filter shift mechanism 33 and then issues a rotation switching command to the filter rotating mechanism 34 when the observation mode switching switch 59 is switched to the special light observation mode.

  In response to the filter switching command from the CPU 54, the filter shift mechanism 33 moves the normal observation rotary filter 31 to the retracted position and moves the special light observation rotary filter 32 to the foreground observation insertion position. Next, the filter rotation mechanism 34 receives the rotation switching command from the CPU 54 and stops the rotation of the normal observation rotation filter 31 and rotates the special light observation rotation filter 32 at a constant speed. As a result, the first B narrowband light filter 41B and the first G narrowband light filter 41G in the foreground viewing filter area 39 are alternately and repeatedly inserted into the optical path of the broadband light BB.

  B narrowband light Bn and G narrowband light Gn are alternately and repeatedly irradiated into the patient's tube from the special light observation rotary filter 32 through the light guide 43 and the like. Thereby, the B narrowband light Bn and the G narrowband light Gn reflected / scattered in the tube enter the CCD 44 through the observation window 19 and the like.

  At this time, the insertion filter discriminating unit 54a determines which of the narrowband light filters 41B and 41G is inserted in the optical path of the broadband light BB based on the rotation speed of the special light observation rotary filter 32 or the like. Determine. Based on the determination result, the CPU 54 controls the imaging control unit 46 to send a drive signal to the CCD 44.

  As shown in FIG. 6B, since the ratio of the areas of the narrowband light filters 41B and 41G is 2: 1, the CCD 44 is rotated 2/3 while the special light observation rotary filter 32 rotates 2/3. During the imaging period for the frame, the B narrowband light Bn is photoelectrically converted and a blue narrowband imaging signal is output to the AFE 45. Next, the CCD 44 photoelectrically converts the G narrowband light Gn and outputs a green narrowband imaging signal to the AFE 45 during the imaging period of one frame while the special light observation rotary filter 32 further rotates by 1/3. As a result, the blue narrow-band imaging signal and the green narrow-band imaging signal are sequentially sent from the AFE 45 to the DSP 55, and the two-color foreground special light image data is generated by the DSP 55 and stored in the frame memory 56.

  The display control circuit 58 reads the two-color foreground special light image data newly stored in the frame memory 56 under the control of the CPU 54. Then, as shown in FIG. 7, the display control circuit 58 causes the monitor 14 to display the foreground special light observation image 60 based on the respective foreground special light image data.

  At the time of near-field observation, the ratio of the area of both the narrowband light filters 41B and 41G is 2: 1, so that the ratio of the B emission time to the G emission time is 2: 1. For this reason, in the imaging period for 3 frames during the rotation of the special light observation rotary filter 32, signal charges are accumulated by photoelectric conversion of the B narrowband light Bn during the imaging period for 2 frames. As a result, in the foreground special light observation image 60, the blue narrow-band image is emphasized more than the green narrow-band image, so the contrast between the superficial blood vessel and the surrounding living tissue becomes higher, and the superficial blood vessel is emphasized more. Can be displayed. Thereby, at the time of foreground observation, superficial blood vessels in which lesions due to early cancer or the like tend to appear can be intensively observed.

  Returning to FIG. 5, under the control of the CPU 54, the observation state determination unit 57 detects the exposure amount at the time of shooting based on the luminance signal of the foreground special light image data newly stored in the frame memory 56. Next, the observation state determination unit 57 determines that the camera is in the foreground observation state when the exposure amount detection result is equal to or greater than a predetermined value, and sends the determination result to the CPU 54. Upon receiving this determination result, the CPU 54 continues the foreground viewing mode. Hereinafter, until the determination result of the observation state determination unit 57 changes to the distant view observation state, the acquisition of the near view special light image data, the display of the close view special light observation image 60, the detection of the exposure amount, and the determination of the observation state Is repeatedly executed.

  The observation state determination unit 57 determines that the observation state is switched to the distant view observation state when the exposure amount detection result is less than a certain value, and sends the determination result to the CPU 54. In response to this determination result, the CPU 54 switches the special light observation mode to the distant view observation mode.

  Next, the CPU 54 issues a distant view observation switching command to the filter shift mechanism 33. Upon receiving this command, the filter shift mechanism 33 moves the special light observation rotary filter 32 to the distant view observation insertion position. Since the rotation of the special light observation rotary filter 32 continues, the second B narrowband light filter 42B and the second G narrowband light filter 42G are alternately inserted into the optical path of the broadband light BB. Thereby, the B narrowband light Bn and the G narrowband light Gn are alternately and repeatedly irradiated into the patient's tube.

  As in the foreground viewing mode, the narrow-band lights Bn and Gn reflected / scattered in the patient's tube enter the CCD 44 through the observation window 19 and the like. At this time, the insertion filter determination unit 54a determines which of the narrowband light filters 42B and 42G is inserted in the optical path of the broadband light BB. Based on the determination result, the CPU 54 controls the imaging control unit 46 to send a drive signal to the CCD 44.

  As shown in FIG. 6C, the ratio of the area of each of the narrowband light filters 42B and 42G is 1: 2, so that the CCD 44 has 1 during the 1/3 rotation of the special light observation rotary filter 32. During the imaging period for the frame, the B narrowband light Bn is photoelectrically converted and a blue narrowband imaging signal is output to the AFE 45. Next, the CCD 44 photoelectrically converts the G narrowband light Gn and outputs a green narrowband imaging signal to the AFE 45 during the imaging period of 2 frames while the special light observation rotary filter 32 further rotates 2/3. As a result, the blue narrow-band imaging signal and the green narrow-band imaging signal are sent from the AFE 45 to the DSP 55, and the two-color distant view special light image data is generated by the DSP 55 and stored in the frame memory 56.

  Under the control of the CPU 54, the display control circuit 58 reads the two-color far-view special light image data newly stored in the frame memory 56. Then, as shown in FIG. 8, the display control circuit 58 causes the monitor 14 to display the distant view special light observation image 61 based on the two colors distant view special light image data.

  At the time of distant view observation, the ratio of the area of each of the narrowband light filters 42B and 42G is 1: 2, so that the ratio of the B emission time and the G emission time is 1: 2. For this reason, in the imaging period for 3 frames during the rotation of the special light observation rotary filter 32, signal charges are accumulated by photoelectric conversion of the G narrowband light Bn during the imaging period for 2 frames. As a result, the green narrowband image is emphasized more than the blue narrowband image in the distant view special light observation image 61.

  Here, since the G narrowband light Gn has a lower hemoglobin absorption coefficient and a scattering coefficient in the living tissue than the B narrowband light Bn, it diffuses deeper and more widely in the living tissue. For this reason, in the distant special light observation image 61 in which the green narrow band image is emphasized, the mucous membrane in the tube becomes brighter. As a result, in the distant view observation, it becomes easy to observe the entire state of the site to be observed including the positional relationship between the surface blood vessels and the middle and deep blood vessels.

  Returning to FIG. 5, the observation state determination unit 57 detects the exposure amount at the time of photographing in the same manner as in the foreground observation mode. And the observation state determination part 57 determines with the distant view observation state being maintained, when the detection result of exposure amount is less than a fixed value. In this case, the CPU 54 continues the distant view observation mode. Hereinafter, until the determination result of the observation state determination unit 57 changes to the foreground observation state, the acquisition of the distant special light image data, the display of the distant special light observation image 61, and the exposure amount based on the distant special light image data Detection and determination of the observation state are repeatedly performed.

  Conversely, when the determination result of the observation state determination unit 57 changes to the foreground observation state, the CPU 54 switches the special light observation mode to the foreground observation mode. As a result, the acquisition of the foreground special light image data, the display of the foreground special light observation image 60, the detection of the exposure amount, and the determination of the observation state are repeated.

  Hereinafter, when the observation state determination unit 57 determines that the foreground observation state is satisfied until the special light observation is completed, the special light observation is performed in a state where “B emission time> G emission time” and the blue narrow band image is emphasized. On the contrary, when it is determined that the distant view observation state is set, “B emission time <G emission time” is satisfied, and the special light observation is performed in a state where the green narrow band image is emphasized. As a result, a good special light image can be obtained according to the photographing conditions such as the near view observation and the distant view observation.

  In the first embodiment, the normal observation rotation filter 31 and the special light observation rotation filter 32 are separately provided in the light source device 13. For example, as in the integrated rotation filter 63 shown in FIG. A normal observation filter area 64 including color filters 37B, 37G, and 37R may be provided inside the observation filter area 39 and the distant view observation filter area 40. In this case, the filter shift mechanism 33 moves the integrated rotation filter 63 so that the normal observation filter area 64 is inserted into the optical path of the broadband light BB in the normal observation mode. Since other operations are the same as those in the first embodiment, description thereof will be omitted.

[Second Embodiment]
Next, an endoscope system according to a second embodiment of the present invention will be described. In the first embodiment, the ratio of the B emission time to the G emission time is changed by changing the area ratio of the narrowband light filters 41B and 41G and the area ratio of the narrowband light filters 42B and 42G. It is changing. In contrast, in the endoscope system according to the second embodiment, the ratio of the B emission time and the G emission time is changed by controlling the rotation of the special light observation rotary filter.

  As shown in FIG. 10, the endoscope system according to the second embodiment is basically the same as the first embodiment except that the endoscope system includes a light source device 66 and a processor device 67 different from the first embodiment. The same functions and configurations as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The light source device 66 has basically the same configuration as the light source device 13 of the first embodiment except that the light source device 66 includes a special light observation rotary filter 69 and a filter rotation mechanism 70 different from the first embodiment. The description of the same configuration as that of the first embodiment is omitted here.

  The special light observation rotary filter 69 includes a B narrowband light filter 71B that transmits the B narrowband light Bn in the broadband light BB, and a G narrowband light filter that transmits the G narrowband light Gn in the broadband light BB. It is a half-cut filter provided with 71G. As the narrow band light filters 71B and 71G, those having the same light transmittance as the respective narrow band optical filters of the first embodiment are used.

  The filter rotation mechanism 70 rotates the special light observation rotary filter 69 so that the narrow band light filters 71B and 71G are alternately inserted in the optical path of the broadband light BB in the special light observation mode. Are rotated intermittently at a pitch of 180 °. A stop time during which the B narrowband light filter 71B is temporarily stopped in the optical path (hereinafter referred to as B stop time), and a stop time during which the G narrowband light filter 71G is temporarily stopped within the optical path (hereinafter referred to as G stop time). Are predetermined for each of the foreground observation mode and the distant view observation mode.

  Specifically, in the foreground observation mode, the ratio between the B stop time and the G stop time is set in accordance with the ratio of the B exit time and the G exit time (B exit time> G exit time) set in advance in the near view observation mode. Is set. In the distant view observation mode, the ratio between the B stop time and the G stop time is set in accordance with the ratio of the B exit time and the G exit time (B exit time <G exit time) predetermined in the distant view observation mode. Has been.

  The filter shift mechanism 33 (see FIG. 2) moves the special light observation rotary filter 69 between an insertion position where it is inserted into the optical path of the broadband light BB and a retracted position where it is retracted from this optical path. .

  The processor device 67 has basically the same configuration as the processor device 12 of the first embodiment except that the processor device 67 includes a CPU 73 and a memory 75 in which a data table 74 is stored. The CPU 73 is basically the same as the CPU 54 of the first embodiment except that it functions as a filter rotation control unit (light source control means) 73a in the special light observation mode.

  In the data table 74, the B stop time and the G stop time in each of the near view observation mode and the distant view observation mode are set. In the near view observation mode, the B stop time is set to “2T” and the G stop time is set to “T”. In the far view observation mode, the B stop time is set to “T” and the G stop time is set to “2T”. Here, “T” is not particularly limited, but for example, is an individual optical path insertion time of each of the color filters 37B, 37G, and 37R in the normal observation mode (that is, individual emission times of B light, G light, and R light). is there.

  In the special light observation mode, the filter rotation control unit 73a controls the filter rotation mechanism 70 based on the determination result of the observation state determination unit 57 and the data table 74 in the memory 75 to intermittently rotate the special light observation rotary filter 69. Rotate.

  Next, the operation of the endoscope system according to the second embodiment, particularly the operation in the special light observation mode will be described in detail with reference to the flowchart shown in FIG. Since the operation in the normal observation mode is basically the same as that in the first embodiment, description thereof is omitted here.

  The CPU 73 issues an insertion switching command to the filter shift mechanism 33 when the observation mode switch 59 is switched to the special light observation mode. Upon receiving this command, the filter shift mechanism 33 moves the normal observation rotary filter 31 to the retracted position and moves the special light observation rotary filter 69 to the insertion position.

  Since the foreground observation mode is set in the initial state, the filter rotation control unit 73a refers to the data table 74 in the memory 75 and determines the B stop time as “2T” and the G stop time as “T”. . Next, the filter rotation control unit 73 a issues a rotation command to the filter rotation mechanism 70.

  The filter rotation mechanism 70 receives the rotation command from the filter rotation control unit 73a, and rotates the special light observation rotation filter for “2T” time with the B narrowband light filter 71B inserted in the optical path of the broadband light BB. 69 is paused. Next, the special light observation rotary filter 69 is rotated by 180 °, and the special light observation rotary filter 69 is inserted for the “T” time in a state where the G narrow band light filter 71G is inserted into the optical path of the broadband light BB. Pause. Then, the special light observation rotary filter 69 is rotated by 180 ° again.

  Similarly, the insertion / pause of the B narrowband light filter 71B for “2T” time and the insertion / pause of the G narrowband light filter 71G for “T” time are alternately repeated. Thus, the B narrowband light Bn and the G narrowband light Gn are alternately and repeatedly emitted from the special light observation rotary filter 69 through the light guide 43 and the like into the patient's tube. Then, the B narrowband light Bn and the G narrowband light Gn reflected / scattered in the tube enter the CCD 44 through the condenser lens 51 and the like.

  At this time, the insertion filter discriminating unit 54a discriminates which of the narrowband light filters 71B and 71G is inserted on the optical path of the broadband light BB by monitoring the operation of the filter rotating mechanism 70 or the like. . Based on the determination result, the CPU 73 controls the imaging control unit 46 to send a drive signal to the CCD 44.

  As shown in FIG. 12A, since the time “T” is equal to the imaging period for one frame while the normal observation rotary filter 31 rotates by 1/3, the CCD 44 has an imaging period of two frames. During the B stop time of “2T”, the B narrowband light Bn is photoelectrically converted and a blue narrowband imaging signal is output to the AFE 45. Next, the CCD 44 photoelectrically converts the G light and outputs a green narrowband imaging signal to the AFE 45 during the next “1T” G stop time which is an imaging period for one frame. As a result, similar to the first embodiment, the generation of the foreground special light image data and the display of the foreground special light observation image 60 are executed.

  Thus, the ratio of the B emission time to the G emission time can be set to 2: 1 by setting the ratio of the B stop time and the G stop time to 2: 1 during close-up viewing. Thereby, the same effect as 1st Embodiment that the superficial blood vessel can be emphasized more at the time of near view observation is acquired.

  Hereinafter, as in the first embodiment, until the determination result of the observation state determination unit 57 changes to the distant view observation state, the acquisition of the foreground special light image data, the display of the foreground special light observation image 60, and the exposure amount Detection and determination of the observation state are repeatedly performed. When the determination result of the observation state determination unit 57 is changed to the distant view observation state, the CPU 73 switches the special light observation mode to the distant view observation mode.

  When switched to the distant view observation mode, the filter rotation control unit 73a refers to the data table 74 and determines the B stop time as “T” and the G stop time as “2T”, and then rotates the filter rotation mechanism 70. Issue a command. As a result, the insertion / pause of the B narrowband light filter 71B for “T” time and the insertion / pause of the G narrowband light filter 71G for “2T” time are alternately and repeatedly executed. In this way, each narrow-band light Bn, Gn is alternately and repeatedly irradiated into the patient's tube.

  The narrow-band lights Bn and Gn reflected / scattered in the patient's tube enter the CCD 44 sequentially through the observation window 19 and the like. Then, the CPU 73 controls the imaging control unit 46 based on the determination result of the insertion filter determination unit 54 a and sends a drive signal to the CCD 44.

  As shown in FIG. 12B, the CCD 44 photoelectrically converts the B narrowband light Bn and outputs a blue narrowband image pickup signal to the AFE 45 during the B stop time of “T” that is an image pickup period for one frame. . Next, the CCD 44 photoelectrically converts the G light and outputs a green image signal to the AFE 45 during the next “2T” G stop time that is an imaging period of two frames. As a result, as in the first embodiment, the generation of the far-field special light image data and the display of the far-view special light observation image 61 are executed.

  As described above, the ratio of the B emission time to the G emission time can be set to 1: 2 by setting the ratio of the B stop time and the G stop time to 1: 2 at the time of distant view observation. Thereby, the same effect as 1st Embodiment that the mucous membrane etc. in a pipe | tube becomes brighter and it becomes easy to observe the whole state of a to-be-observed site | part is acquired. Then, until the determination result of the observation state determination unit 57 changes to the distant view observation state, acquisition of the far view special light image data, display of the distant view special light observation image 61, and the exposure amount based on the distant view special light image data Detection and determination of the observation state are repeatedly performed. When the observation state determination unit 57 determines that the foreground inspection state is set, the CPU 73 switches the special light observation mode to the foreground observation mode.

  Thereafter, until the special light observation is completed, the special light observation is performed in the state where “B emission time> G emission time” in the near view observation mode as in the first embodiment, and conversely, in the far view observation mode, “ Special light observation is performed in a state where B emission time <G emission time ”. As a result, similar to the first embodiment, a good special light image can be obtained in accordance with shooting conditions such as foreground observation and distant view observation.

  In the second embodiment, the special light observation rotary filter 69 is provided separately from the normal observation rotary filter 31. For example, as in the integrated rotary filter 78 shown in FIG. A normal observation filter area 79 composed of the color filters 37B, 37G, and 37R may be provided inside the filters 71B and 71G. In the integrated rotating filter 78, the normal observation filter area 79 is inserted into the optical path of the broadband light BB in the normal observation mode, and the narrowband light filters 71B and 71G are inserted into the optical path in the special light observation mode.

  In the second embodiment, the special light observation rotary filter 69 is intermittently rotated. However, it is not necessary to temporarily stop the rotation of the special light observation rotary filter 69. For example, an insertion time for inserting the B narrowband light filter 71B into the optical path of the broadband light BB and an insertion time for inserting the G narrowband light filter 71G into the optical path are determined for each observation mode. The rotation speed of the special light observation rotary filter 69 may be controlled to be equal to the B emission time and the G emission time.

  In the first embodiment, the areas of the narrowband light filters 42B and 42G in the distant view observation filter area 40 are set so that B emission time <G emission time. For example, as shown in FIG. As in the distant view observation filter area 82 of the special light observation rotary filter 81, the area of each of the narrowband light filters 83B and 83G may be set so that the B emission time = G emission time. In this case, an observation image in which both the superficial blood vessels and the mid-deep blood vessels are highlighted is obtained at the time of distant view observation, so that the positional relationship between the superficial blood vessels and the mid-deep blood vessels can be more easily grasped. In addition, when performing the same thing in 2nd Embodiment, what is necessary is just to control rotation of the rotation filter 69 for special light observation so that it may become B stop time = G stop time.

  In each of the above embodiments, the G narrowband light and the B narrowband light are emitted from the light source device 13 in the special light observation mode. However, the wavelength band of the narrowband light used as the illumination light is not particularly limited. Each color narrow band light including the narrow band light may be emitted from the light source device 13.

  In the above embodiments, the CPUs of the processor devices 12 and 67 control the respective units of the light source devices 13 and 66. However, a control unit such as a CPU that controls these units may be provided in the light source devices 13 and 66.

  In the above embodiment, broadband light and narrow band light are emitted from the light source device 13 to the electronic endoscope 11. However, a light source of these broadband light and narrow band light may be provided in the insertion portion distal end portion 16 a.

  In each of the above-described embodiments, foreground observation and distant view observation are described as examples of imaging conditions. However, the imaging conditions may be, for example, high / low reflectance of the site to be observed. Specifically, in this case, the reflectance of the observation site is obtained by a method such as analyzing the observation image. When the reflectance of the observation site is high, B emission time> G emission time, and When the reflectance is low, emission time switching control is performed so that B emission time <G emission time.

  In each of the above embodiments, the ratio of the area of each filter and the ratio of the B and G stop times are set so that the ratio of the B emission time to the G emission time is 2: 1. You may change it.

  In the above-described embodiment, the endoscope system that performs the special light observation of the surface blood vessel and the middle-deep blood vessel using light of two types of specific wavelengths has been described as an example, but the two types of specific wavelengths are described. The present invention is applied to an endoscope system used for various observations and diagnoses such as fluorescence observation (Auto Fluorescence Imaging), infrared light observation (Infra Red Imaging), and photodynamic diagnosis (Photodynamic diagnosis). Can be applied.

DESCRIPTION OF SYMBOLS 10 Endoscope system 11 Electronic endoscope 12,67 Processor unit 13,68 Light source device 32,69 Special light observation rotation filter 33 Filter shift mechanism 34,70 Filter rotation mechanism 39 Near view observation filter area 40 Distant view observation filter Area 41B, 41G First blue narrow band light filter, first green narrow band light filter 42B, 42G Second blue narrow band light filter, second green narrow band light filter 54, 73 CPU
71B, 71G Blue narrowband light filter, green narrowband light filter 73a Filter rotation control unit 74 Data table

Claims (10)

A narrow-band light source that repeatedly emits first and second narrow-band lights having different wavelength bands used for special light observation in a predetermined order;
Imaging means for obtaining an observation image of the observed site by imaging the observed site irradiated with each of the first to second narrowband lights;
Light source control means for controlling a first emission time of the first narrowband light emitted from the narrowband light source and a second emission time of the second narrowband light;
An endoscope system comprising: Based on the observation image obtained by the imaging means, provided with imaging condition detection means for detecting a predetermined imaging condition at the time of acquisition,
The endoscope system according to claim 1, wherein the light source control unit changes the first and second emission times according to the imaging condition detected by the imaging condition detection unit. The second narrowband light has a wavelength band longer than the wavelength band of the first narrowband light,
Whether the imaging condition detection means is in a near-field observation state where the distance between the distal end portion of the endoscope and the site to be observed is close or a distant view observation state where the distance is far as the imaging condition Detect
The light source control means is configured such that the first emission time is longer than the second emission time when the photographing condition detection means detects the near view observation state, and the first light emission control time when the distant view observation state is detected. The endoscope system according to claim 2, wherein the narrow-band light source is controlled so that two emission times are longer than the first emission time. The narrow-band light source is
A broadband light source that emits white broadband light;
A substantially annular filter area having a first filter that transmits the first narrowband light of the broadband light and a second filter that transmits the second narrowband light of the broadband light, with a rotation axis as a center. A rotation filter provided concentrically for each imaging condition;
A filter area inserting means for moving the rotary filter in a radial direction thereof and selectively inserting one of the individual filter areas into the optical path of the broadband light;
Filter rotating means for rotating the rotary filter around the rotation axis,
In the rotary filter, the ratio of the areas of the first and second filters in each filter area is set in accordance with the ratio of the first and second emission times determined in advance for each imaging condition. The endoscope system according to claim 2 or 3, characterized by the above.   5. The light source control means controls the filter area inserting means so that the filter area corresponding to the photographing condition detected by the photographing condition detecting means is inserted into the optical path. Endoscope system.   The rotary filter includes a first narrowband optical priority filter area formed such that an area of the first filter is larger than an area of the second filter, and an area of the second filter is larger than an area of the first filter. The endoscope system according to claim 4, further comprising a second narrowband light priority filter area formed.   The light source control means, based on the imaging conditions detected by the imaging condition detection means, according to the first to second emission time preset values set in the imaging conditions, the first to second narrowband lights. 4. The endoscope system according to claim 2, wherein the narrow-band light source is controlled so that each of the light sources is emitted. The narrow-band light source is
A broadband light source that emits white broadband light;
A rotary filter disposed in the optical path of the broadband light and having a first filter that transmits the first narrowband light of the broadband light, and a second filter that transmits the second narrowband light of the broadband light; ,
Filter rotation means for rotating the rotary filter and alternately inserting the first filter and the second filter into the optical path;
The light source control means controls the filter rotation means so that the insertion time for inserting the first and second filters into the optical path is equal to the set value of the first and second emission times, respectively. The endoscope system according to claim 7. The filter rotating means intermittently rotates the rotary filter such that the first filter and the second filter are temporarily stopped in a state where each of the first filter and the second filter is inserted in the optical path of the broadband light.
9. The endoscope system according to claim 8, wherein a time during which each of the first and second filters is temporarily stopped in the optical path is equal to a set value of the first and second emission times. 10.   The first and second narrowband lights are light used for highlighting blood vessels in the living tissue, and blue narrowband light having a wavelength corresponding to the absorption peak of the absorption spectrum of hemoglobin light, green The endoscope system according to any one of claims 1 to 9, wherein the endoscope system is narrowband light.

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