JP5877614B2 - Endoscope system and method for operating endoscope system - Google Patents

Description

  The present invention relates to an endoscope system that performs special light observation of a plurality of sites to be observed such as an esophagus and a stomach, and an operation method of the endoscope system.

  2. Description of the Related Art In recent years, endoscope systems that perform so-called special light observation in which a living tissue is irradiated with light of a specific narrow wavelength band (narrow band light) to obtain an observation image that emphasizes blood vessels in the living tissue are known. (For example, refer to 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.

  The endoscope system of Patent Literature 1 includes a white light source and a rotary filter provided with two types of bandpass filters that respectively transmit blue narrow band light and green narrow band light, and rotates the rotary filter. In accordance with the timing, two types of band-pass filters are alternately inserted into the optical path of the white light source, and a frame sequential type imaging method is adopted in which an image sensor is used to take images of two types of narrowband light in a time-sharing manner. ing. 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.

  However, the frame sequential method described in Patent Document 1 has a problem that it is difficult to increase the frame rate because the observation images using two types of narrowband light are sequentially captured. As a solution to this problem, for example, a mixed simultaneous irradiation method in which two types of narrowband light are simultaneously irradiated and an observation image by each narrowband light is simultaneously acquired has been studied (see Patent Document 2). According to the mixed simultaneous irradiation method, the frame rate can be increased as compared with the frame sequential method.

Japanese Patent Laid-Open No. 2001-170009 JP 2009-207584 A

  In special light observation, the observation target varies depending on the type of the site to be observed. Therefore, the illumination light is usually switched to make the observation target easier to see. For example, superficial blood vessels are gathered in the esophagus, and in order to make it easy to observe the superficial blood vessels, in the special light observation of the esophagus, illumination light in which the light amount of B narrowband light is increased than the light amount of G narrowband light is used. Used. In addition, since the mid-deep blood vessels are gathered in the cardia at the junction between the esophagus and the stomach, the illumination light in which the light amount of the G narrow band light is increased more than the light amount of the B narrow band light in the special light observation of the cardia. Used. Further, in the special light observation of the stomach, illumination light obtained by adding white light to both narrow-band lights is used in order to brighten the observation image of the stomach where the dark part extends to the back.

  Such switching of the illumination light needs to be performed manually. This causes a problem that the operator's labor is increased particularly when special light observation from the esophagus to the stomach is continuously performed.

  The present invention has been made to solve the above-described problem, and is an endoscope capable of performing special light observation with optimal illumination light according to the type of a region to be observed without performing illumination light switching operation. It is an object of the present invention to provide a system and a method for operating an endoscope system.

In order to achieve the above object, an endoscope system of the present invention includes a light source that emits narrowband light and broadband light, a first illumination mode in which the amount of narrowband light is larger than the amount of broadband light, Light is emitted in any one of the second illumination mode in which the light amount of the band light and the light amount of the broadband light are substantially equal and the third illumination mode in which the light amount of the narrow band light is reduced from the light amount of the broadband light. A light source control means for controlling the light source and an insertion portion inserted into the subject, and the narrow-band light and the broadband light emitted from the light source are transmitted from the distal end portion of the insertion portion to the observation site in the subject. An endoscope to be irradiated, a first blood vessel highlighted with narrow band light out of narrow band light and broadband light, and highlighted with broadband light out of narrow band light and broadband light, than the first blood vessel Imaging means for imaging an image of the second blood vessel in the deep part to obtain an observation image; By analyzing the image data of Sazzo, a processor device to obtain the density of the first vessel and the area of the density and the dark of the second vessel, and the density of the first vessel more than the upper limit value, further dark area Is lower than the lower limit and lower than the upper limit, light is emitted in the first illumination mode, the density of the second blood vessel is higher than the upper limit, and the area of the dark part is lower than the lower limit. And a processor device for controlling the light source control means to emit light in the illumination mode .

  A monitor for displaying the observation image, and display control means for outputting the R, G, B pixel values of the observation image to a predetermined channel in accordance with the type of illumination mode among the R, G, B channels of the monitor; Are preferably provided.

  The display control means outputs the B pixel value to the B and G channels in the first to second illumination modes, outputs the G pixel value to the R channel, and outputs the R, G, and B pixel values in the third illumination mode. It is preferable to output to the R, G and B channels.

  In the first illumination mode, it is preferable to include high-pass filter processing means for performing high-pass filter processing for enhancing high-frequency components on the image data of the observation image. In the second illumination mode, it is preferable that the image data of the observation image is provided with a band-pass filter processing unit that performs band-pass filter processing that emphasizes a medium frequency component within a predetermined range.

  The narrowband light is preferably blue narrowband light having a wavelength corresponding to the absorption peak of the absorption spectrum of hemoglobin light. The broadband light is preferably green light having a wavelength of about 500 nm to 600 nm.

In addition, according to the operation method of the endoscope system of the present invention, the light source emits the narrowband light and the broadband light, and the light source control unit increases the light amount of the narrowband light more than the light amount of the broadband light. Any one of the illumination mode, the second illumination mode in which the light amount of the narrow band light and the light amount of the broadband light are substantially equal, and the third illumination mode in which the light amount of the narrow band light is reduced from the light amount of the broadband light The step of controlling the light source to emit light in the mode; and the imaging means highlights the first blood vessel highlighted with the narrowband light of the narrowband light and the broadband light; and Imaging a second blood vessel highlighted by broadband light and deeper than the first blood vessel to obtain an observation image; and a processor device analyzing the image data of the observation image to determine the density of the first blood vessel Step to obtain the density of the second blood vessel and the area of the dark part When the processor device is a density of the first vessel more than the upper limit value, further when the area of the dark part is less than the above lower limit and upper limit, light is emitted in the first illumination mode, the density of the second vessel And a step of controlling the light source control means so that light is emitted in the second illumination mode when the area of the dark part is less than the lower limit value .

  According to the endoscope system and the operation method of the endoscope system of the present invention, the type of the site to be observed is determined, and illumination light predetermined for each type is irradiated to the site to be observed. The special light observation can be performed with the optimum illumination light according to the type of the observation site without performing the operation. As a result, the labor of the operator can be reduced.

It is a schematic diagram of an endoscope system. It is explanatory drawing for demonstrating the insertion path | route of an electronic endoscope. It is a block diagram which shows the electric constitution of an endoscope system. It is explanatory drawing for demonstrating the function of a micro filter. It is explanatory drawing of a data table. It is the flowchart which showed the flow of the special light observation process. It is a block diagram which shows the light source device at the time of special light observation mode. It is explanatory drawing for demonstrating the display of a monitor when a color channel allocation is set to "special allocation." It shows an example of an observation image of the esophagus. An example of an observation image of the cardia is shown. It is explanatory drawing for demonstrating other embodiment of the process in which a site | part detection part recognizes a cardia. It is explanatory drawing for demonstrating the display of a monitor when color channel allocation is set to "normal allocation". It shows an example of an observed image of the stomach. It is a block diagram which shows the electric constitution of the endoscope system of 2nd Embodiment which performs a spatial frequency process to special light image data. It is a block diagram which shows the electric constitution of the endoscope system of other embodiment which enabled adjustment of the light quantity ratio of B narrow-band light and broadband light.

[First Embodiment]
As shown in FIG. 1, an endoscope system 10 includes an electronic endoscope 11 that images a region to be observed in a patient, and an observation image of the region to be observed based on an imaging signal obtained by the electronic endoscope 11. , A light source device 13 for emitting illumination light for illuminating the site to be observed to the electronic endoscope 11, and a monitor 14 for displaying an observation image. This endoscope system is used particularly when special light observation is performed on the esophagus, cardia, and stomach as the observation site.

  The endoscope system 10 is broadly divided into a normal observation mode in which the entire observation site is observed by illuminating the inside of the body with broadband light such as white light, and narrowband light in which the observation site is limited in wavelength band. There are two observation modes: a special light observation mode for observing in a state in which a blood vessel is highlighted with illumination.

  In the special light observation mode, a first illumination mode that uses illumination light suitable for special light observation of the esophagus and a second illumination that uses illumination light suitable for special light observation of the cardia according to the type of site to be observed. Either the mode or the third illumination mode using illumination light suitable for special light observation of the stomach is selectively executed.

  The electronic endoscope 11 is connected to a flexible insertion portion 16 to be inserted into the body 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. In addition to the observation window 19 (see FIG. 3) and the illumination window 20 (see FIG. 3), 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 electronic endoscope 11 is a so-called upper digestive tract endoscope in which the insertion portion 16 is inserted into the body from the mouth of the patient H, and the esophagus E, cardia as indicated by arrows in the figure. The inside of each upper digestive tract such as C and stomach S is photographed in order.

  As shown in FIG. 3, the light source device 13 includes a broadband light source 30, a blue semiconductor laser device (hereinafter simply referred to as blue LD) 31, a dichroic mirror (hereinafter simply referred to as D mirror) 32, and a movable diaphragm (hereinafter referred to as “light emitting device”). 34a and 34b), a condensing lens 35, a mirror shift mechanism 36, and a light source drive control unit 37.

  As the broadband light source 30, for example, a xenon lamp, a white LED, or a micro white light source (a set of a light source that emits light having a central wavelength of 445 nm and a phosphor that emits excitation light by irradiation of this light) is used. To WB in the blue region (about 470 to 700 nm). The broadband light source 30 always emits broadband light BB. A D mirror 32 and a condenser lens 35 are sequentially arranged from the upstream side to the downstream side of the optical path of the broadband light BB emitted from the broadband light source 30.

  The blue LD 31 emits blue (B) narrowband light Bn limited to a specific wavelength band of blue (for example, a center wavelength of 405 nm) toward the D mirror 32 in the special light observation mode. The optical path of the B narrowband light Bn is substantially orthogonal to the optical path of the broadband light BB. A blue LED or the like may be used instead of the blue LD as the light source of the B narrowband light Bn.

  The wavelength band of the B narrowband light Bn is adjusted in accordance with the absorption peak (near 415 nm) of the absorption spectrum of hemoglobin light. From the knowledge about the light scattering characteristics of the living tissue, most of the irradiated light is absorbed by the surface blood vessel and does not return to the insertion portion tip 16a unless the wavelength of the irradiated light exceeds about 470 nm. 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 can be sufficiently highlighted.

  On the other hand, highlighting of the middle-deep blood vessels is performed using green light having a wavelength of about 500 nm to about 600 nm included in the broadband light BB without using green narrowband light as described in Patent Document 1 above. From the knowledge about the light scattering characteristics of living tissue, when the wavelength of the irradiated light is between 500 nm and 600 nm, the light reaches the mid-deep blood vessel deeper than the surface blood vessel. 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.

  Note that the broadband light BB includes light other than green light, but the wavelength band in which the middle-layer blood vessel can be highlighted is sufficiently wider than the wavelength band in which the surface blood vessel can be highlighted. For this reason, the contrast reduction of the middle-deep blood vessel due to the influence of light other than green light can be minimized. On the contrary, in the present embodiment, there is no need to separately provide a narrow band light source that emits green narrow band light as in Patent Document 1, so that space saving and cost reduction can be achieved.

  The D mirror 32 is movably disposed at a position where the optical path of the broadband light BB and the optical path of the B narrowband light Bn emitted from the blue LD 31 intersect (hereinafter referred to as an intersection position). The D mirror 32 reflects the B narrowband light Bn, but transmits light of other wavelengths. As a result, most of the broadband light BB passes through the D mirror 32 and enters the condenser lens 35. Further, the B narrowband light Bn is reflected by the D mirror 32 and enters the condenser lens 35.

  The diaphragm 34 a is disposed in front of the broadband light source 30 and adjusts the amount of broadband light BB emitted from the broadband light source 30. The stop 34b is disposed in front of the blue LD 31 and adjusts the amount of B narrowband light Bn emitted from the blue LD 31.

  The condenser lens 35 causes the broadband light BB and the B narrowband light Bn incident from the D mirror 32 to enter the light guide 41. The mirror shift mechanism 36 holds the D mirror 32 so as to be movable between the intersecting position and a retracted position retracted from the intersecting position. Under the control of the processor unit 12, the mirror shift mechanism 36 moves the D mirror 32 to the retracted position in the normal observation mode, and moves the D mirror 32 to the intersecting position in the special light observation mode.

  The light source drive control unit 37 controls the emission / emission stop of the B narrowband light Bn from the blue LD 31 under the control of the processor device 12. The light source drive control unit 37 stops the emission of the B narrow band light Bn from the blue LD 31 in the normal observation mode, and emits the B narrow band light Bn from the blue LD 31 in the special light observation mode.

  In addition, the light source drive control unit 37 changes the area of the apertures of the apertures 34a and 34b by narrowing or opening the apertures 34a and 34b under the control of the processor device 12, thereby changing the special light observation mode. The light quantity ratio between the broadband light BB and the B narrowband light Bn respectively emitted from the broadband light source 30 and the blue LD 31 in each illumination mode is controlled. In the first illumination mode, the light source drive control unit 37 increases the light amount of the B narrowband light Bn, and in the second illumination mode, the light amounts of the broadband light BB and the B narrowband light Bn are equal. At times, the apertures 34a and 34b are controlled so that the amount of the broadband light BB is increased.

  With each configuration described above, the light source device 13 causes the broadband light BB to be incident on the light guide 41 in the normal observation mode, and mixes the broadband light BB and the B narrowband light Bn having different light quantity ratios in the first to third illumination modes. Light is incident on the light guide 41.

  The electronic endoscope 11 includes a light guide 41, 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 41 is a large-diameter optical fiber, a bundle fiber, or the like. The light guide 41 has an incident end inserted into the light source device 13 and an emission end opposed to the 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 41 is irradiated to the observation site through the illumination window 20. Then, the light reflected / scattered at the site to be observed 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 52 (hereinafter referred to as PD 52, see FIG. 4) are two-dimensionally arranged, and subject light incident from the condenser lens 51 is electrically imaged by each PD 52. It converts into a signal and outputs it to AFE45. 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 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.

  As shown in FIG. 4, the CCD 44 is a color CCD including red, green, and blue microfilters FR, FG, and FB two-dimensionally arranged on each PD 52. The CCD 44 includes an R pixel composed of a microfilter FR and a PD 52 disposed below (in the drawing, side, the same applies hereinafter), a G pixel composed of a microfilter FG and a PD 52 disposed below, and a microfilter FB. And a B pixel composed of PD 52 disposed below the B pixel.

  The microfilter FR transmits red (R) light in the red band of the broadband light BB. The microfilter FG transmits green (G) light in the green band of the broadband light BB. The microfilter FB transmits blue (B) light in the blue band of the broadband light BB. The light incident on the imaging surface 44a can be separated into three colors of RGB by the microfilters FR, FG, and FB. The B light includes B narrowband light Bn.

  Returning to FIG. 3, 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 memory 53, a CPU 54, a digital signal processor (DSP) 55, a frame memory 56, a part determination unit 57, a display control circuit 58, and a mode switch 59. ing. The memory 53 stores a data table 61 in addition to various programs and data for controlling the endoscope system 10.

  The CPU 54 is connected to each part of the processor device 12 and the mirror shift mechanism 36 and the light source drive control unit 37 of the light source device 13 through signal lines, and comprehensively controls them based on programs and data read from the memory 53. To do.

  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 signal processing on the B imaging signal, the G imaging signal, and the R imaging signal input from the AFE 45, thereby generating normal image data having pixel values of three colors B, G, and R. Generate. The normal image data is stored in the frame memory 56.

  On the other hand, when the observation mode is set to the special light observation mode, the DSP 55 appropriately performs signal processing on the B imaging signal (including the B narrowband imaging signal), the G imaging signal, and the R imaging signal input from the AFE 45. As a result, special light image data having pixel values of three colors B, G, and R is generated. This special light image data is also stored in the frame memory 56.

  The part discriminating unit 57 operates in the special light observation mode. The site determination unit 57 analyzes the special light image data newly stored in the frame memory 56 and determines whether the site to be observed is the esophagus E, the cardia C, or the stomach S. For example, the diameter of the upper gastrointestinal tract from the esophagus E to the stomach S is not constant but is different in each part. Specifically, the upper gastrointestinal tract has the smallest cardia C, and the stomach S has the largest diameter. In the special light image data, the internal space of the upper gastrointestinal tract located in the forward direction of the insertion portion distal end portion 16a is a dark portion BL (see FIG. 9). For this reason, by obtaining the area of the dark part BL, the type of the observed region can be determined.

  In addition, surface blood vessels gather in the esophagus E, and mid-deep blood vessels gather in the cardia C. For this reason, it is possible to discriminate the type of the site to be observed using these surface blood vessels and middle-deep blood vessels as landmarks.

  For example, when the area of the dark part BL is not less than a predetermined area lower limit value and less than the area upper limit value, and the density of the superficial blood vessels is not less than the predetermined density upper limit value, the site determination unit 57 determines that the site to be observed is the esophagus E It is determined that In addition, the region determination unit 57 determines that the region to be observed is the cardia C when the area of the dark part BL is less than the area lower limit value and the density of the mid-deep blood vessels is equal to or higher than the density upper limit value. And the part discrimination | determination part 57 discriminate | determines that the to-be-observed part is the stomach S, when the area of the dark part BL is more than an area upper limit. The discrimination result of the part discrimination unit 57 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 from the frame memory 56 and displays the normal image on the monitor 14 based on the normal image data. When displaying a normal image on the monitor 14, as shown in FIG. 4, the pixel values of the three colors B, G, and R of the normal image data are assigned to the B channel, G channel, and R channel of the monitor 14, respectively. Output.

  On the other hand, when the observation mode is the first to second illumination modes, the display control circuit 58 reads the special light image data from the frame memory 56 and displays the special light image on the monitor 14 based on the special light image data. Display. When displaying this special light image, the B pixel value acquired by the B pixel of the CCD 44 is assigned to the B and G channels of the monitor 14, and the G pixel value acquired by the G pixel is assigned to the R channel of the monitor 14 (FIG. 8). The surface layer blood vessel portion of the special light image displayed on the monitor 14 has a pixel value close to “0” due to absorption of the B narrowband light Bn, so that the B and G channels are darkened, and only the R channel is relatively Since it becomes brighter, it is displayed in brown. In addition, since the R channel becomes dark due to absorption of G light having a wavelength of about 500 nm to 600 nm, the middle-deep blood vessel portion is displayed in a cyan color or green color in which the B and G channels are mixed.

  Further, when the observation mode is the third illumination mode, the display control circuit 58 sets the pixel values of the three colors B, G, and R of the special light image data basically in the same manner as in the normal observation mode. , Assigned to the B channel, G channel, and R channel of the monitor 14, respectively, for output.

  The mode switch 59 is provided, for example, on the front panel of the processor device 12 and is operated when the observation mode of the endoscope system 10 is switched to the normal observation mode or the special light observation mode. The CPU 54 controls each part of the light source device 13 according to the type of observation mode set by the mode switch 59 and switches the type of illumination light emitted from the light source device 13. The mode switch 59 may be provided in the operation unit 17 of the electronic endoscope 11.

  As shown in FIG. 5, the data table 61 includes first to third illumination modes, sites to be observed (esophagus E, cardia C, stomach S) corresponding to each illumination mode, and B narrowband light Bn. A light amount ratio with the broadband light BB (hereinafter simply referred to as a light amount ratio) and a color channel assignment indicating assignment of each color pixel value to each color channel of the monitor 14 are stored in association with each other.

  There are two types of color channel allocation: normal allocation and special allocation. In the normal allocation, the pixel values of the three colors B, G, and R of the image data are output to the B channel, G channel, and R channel of the monitor 14, respectively. In the special allocation, the B pixel value of the image data is output to the B and G channels, and the G pixel value is output to the R channel. Thus, the CPU 54 can determine the illumination mode, the light amount ratio, and the color channel assignment from the type of the observed region by referring to the data table 61.

  The CPU 54 functions as an emission control unit (light source control means) 63 and a display control unit 64 by sequentially executing various programs read from the ROM. The emission control unit 63 operates in the special light observation mode. The emission control unit 63 refers to the data table 61 based on the determination result of the region determination unit 57, the illumination mode corresponding to the observed region determined by the region determination unit 57, and the light amount ratio corresponding to this illumination mode. And the light source drive control unit 37 is controlled according to the determination result. Thereby, illumination light suitable for special light observation of the observed region determined by the region determining unit 57 is emitted from the light source device 13.

  The display control unit 64 operates in the special light observation mode. The display control unit 64 determines the color channel assignment corresponding to the illumination mode determined by the emission control unit 63 with reference to the data table 61, and controls the display control circuit 58 according to the determination result. Thereby, the color tone of the observation image displayed on the monitor 14 is switched according to the type of the site to be observed.

  Next, the operation of the endoscope system 10 configured as described above, particularly the operation in the special light observation mode, will be described in detail with reference to 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, the CCD 44 starts to be driven and the broadband light source 30 emits the broadband light BB. Is emitted. Note that the endoscope system 10 is set to the normal observation mode in the initial state when the power is turned on, but the normal observation using the broadband light BB is basically the same as the conventional one, so that the inspection in the normal observation mode is performed. Description of is omitted.

  After completion of the examination preparation process, the insertion portion 16 is inserted into the esophagus E from the mouth of the patient H. When the special light observation from the esophagus E to the stomach S is continuously performed, the mode switch 59 is switched to the special light observation mode. In the special light observation mode, for example, the first illumination mode is set in the initial state.

  The CPU 54 issues an insertion command to the mirror shift mechanism 36 of the light source device 13 when the mode switch 59 is switched to the special light observation mode. In response to the insertion command from the CPU 54, the mirror shift mechanism 36 moves the D mirror 32 to the crossing position.

  Simultaneously with the switching to the special light observation mode, the emission control unit 63 and the display control unit 64 of the CPU 54 operate. The emission control unit 63 issues a first illumination mode switching command including information on the light amount ratio (Bn: BB = 4: 1) to the light source drive control unit 37. The display control unit 64 waits until new special light image data is stored in the frame memory 56.

  As illustrated in FIG. 7, the light source drive control unit 37 receives the first illumination mode switching command from the emission control unit 63 and controls the diaphragms 34 a and 34 b, so that the B narrowband light from the blue LD 31 and the broadband light source 30 respectively. Bn and broadband light BB are emitted at a light quantity ratio of 4: 1.

  The broadband light BB emitted from the broadband light source 30 passes through the D mirror 32 and enters the condenser lens 35. Further, the B narrowband light Bn emitted from the blue LD 31 is reflected toward the condenser lens 35 by the D mirror 32. As a result, mixed light (hereinafter, referred to as first mixed light) Bn and BB of the B narrowband light Bn and the broadband light BB having a light amount ratio of 4: 1 is incident on the condenser lens 35. The first mixed lights Bn and BB enter the light guide 41 through the condenser lens 35.

  The first mixed lights Bn and BB incident on the light guide 41 are irradiated into the esophagus E from the illumination window 20 through the irradiation lens 48. As a result, the first mixed light Bn and BB reflected / scattered in the esophagus E enters the CCD 44 through the observation window 19 and the condenser lens 51.

  As shown in FIG. 8, out of the first mixed light Bn and BB incident on the CCD 44, the B light and B narrow-band light Bn incident on the microfilter FB are transmitted below the microfilter FB and disposed below them. Light is received by the PD 52. Further, the G light incident on the microfilter FG passes through the microfilter FG and is received by the PD 52 disposed below the microfilter FG. Further, the R light incident on the microfilter FR passes through the microfilter FR and is received by the PD 52 disposed therebelow. Each PD 52 converts the received light into an electrical imaging signal and outputs it to the AFE 45. The AFE 45 performs various signal processing on each color image pickup signal from the CCD 44 and outputs each digital color image pickup signal to the DSP 55 of the processor unit 12.

  Each color image signal is subjected to various signal processing by the DSP 55 and then stored in the frame memory 56 as special light image data. When the new special light image data is stored in the frame memory 56 and the observation mode is the first illumination mode, the display control unit 64 refers to the data table 61 and specially assigns the color channel. Decide on allocation. Next, the display control unit 64 issues a special assignment display command to the display control circuit 58.

  The display control circuit 58 receives the special assignment display command from the display control unit 64, reads the special light image data newly stored in the frame memory 56, and sets the B pixel value of the special light image data as B, B of the monitor 14. In addition to outputting to the G channel, the G pixel value is output to the R channel of the monitor 14. Thereby, the observation image 66a (see FIG. 9) in the esophagus E is displayed on the monitor 14.

  As shown in FIG. 9, the B narrowband imaging signal is amplified because the amount of B narrowband light Bn is increased in the first illumination mode. As a result, in the observation image 66a, the superficial blood vessels gathered in the esophagus E are highlighted in brown. Thereby, the superficial blood vessels can be observed intensively. In addition, the code | symbol V1 in a figure is a surface layer blood vessel.

  In parallel with the display of the observation image 66a, the region determination unit 57, the area of the dark portion BL obtained by analyzing the special light image data newly stored in the frame memory 56, the density of the superficial blood vessels displayed in brown, In addition, the type of the site to be observed is determined based on the density of the middle-deep blood vessels displayed in cyan or green, and the determination result is sent to the CPU 54.

  When the part discriminating unit 57 discriminates the site to be observed as the esophagus E, the illumination light is emitted under the first illumination mode, the special light image data is acquired, the observation image 66a is displayed, and the site to be observed is discriminated. Is executed continuously.

  On the other hand, when the insertion portion 16 is pushed further into the esophagus E and the insertion portion distal end portion 16a reaches the vicinity of the cardia C, the area of the dark portion BL in the observation image 66a and the density of the surface blood vessels are determined. As it decreases, the density of the middle blood vessels increases. For this reason, the part discriminating unit 57 is the cardia C when the area of the dark part BL is less than the predetermined area lower limit value and the density of the middle-deep blood vessel is equal to or higher than the predetermined density upper limit value. And the determination result is sent to the CPU 54.

  The emission control unit 63 refers to the data table 61 based on the determination result of the part determination unit 57 and determines the observation mode to be the second illumination mode, and to the light source drive control unit 37, the light amount ratio (Bn: A second illumination mode switching command including information of BB = 1: 1) is issued.

  The light source drive control unit 37 receives the second illumination mode switching command from the emission control unit 63 and controls the diaphragms 34a and 34b, from the blue LD 31 and the broadband light source 30 so that the light quantity ratio Bn: BB = 1: 1. The light amounts of the B narrowband light Bn and the broadband light BB emitted are adjusted. As a result, mixed light (hereinafter referred to as second mixed light) Bn and BB of the B narrowband light Bn and the broadband light BB having a light amount ratio of 1: 1 is irradiated onto the cardia C and its periphery.

  The second mixed light Bn and BB reflected / scattered around the cardia C enters the CCD 44 through the observation window 19 and the like. Thereby, special light image data is generated and stored in the frame memory 56 as in the first illumination mode.

  When the new special light image data is stored in the frame memory 56 and the observation mode is the second illumination mode when the new special light image data is stored in the frame memory 56, the display control unit 64 sends the display control circuit 64 to the display control circuit 58. In response, a special assignment display command is issued. As a result, as shown in FIG. 10, an observation image 66 b near the cardia C is displayed on the monitor 14. In addition, the code | symbol V2 in a figure is a middle-deep layer blood vessel.

  In the second illumination mode, the light amount of the broadband light BB is increased compared to the first illumination mode, so the light amount of G light in the vicinity of the wavelength of 500 nm to 600 nm included in the broadband light BB also increases. As a result, in the observation image 66b, the mid-deep blood vessels gathered around the cardia C are highlighted in cyan or green. Thereby, it is possible to observe the middle-deep blood vessel intensively.

  Note that, since the light amount of the broadband light BB is small under the first illumination mode, it is difficult to detect the mid-deep blood vessel even if the special light image data is analyzed. For this reason, when the distal end portion 16a of the insertion portion reaches the vicinity of the cardia C, if the determination result of the density of the middle-deep blood vessel by the region determination portion 57 is lower than the actual density, the second illumination mode is entered. May be delayed. In this case, it may be difficult to observe the mid-deep blood vessels around the cardia C.

  Therefore, as shown in FIG. 11, the recognition degree by which the part discriminating unit 57 recognizes the cardia C is 100% (for example, the area of the dark part BL is less than a predetermined area lower limit “X” and the density of the middle-deep blood vessels is predetermined). Before reaching the density upper limit value “Y” or higher), the switching to the second illumination mode may be performed when the recognition level reaches 20%, for example. The degree of recognition of 20% is a value that can predict the presence of cardia C to some extent, for example, such that the area of the dark part BL is less than “2X” and the density of the middle-deep blood vessels is “Y / 2” or more. .

  In this way, by predicting the presence of the cardia C and accelerating the switching to the second illumination mode, the accuracy of detecting the mid-deep blood vessel by the region determination unit 57 is increased, and the accuracy of recognizing the cardia C is increased. As a result, when the insertion portion distal end portion 16a reaches the vicinity of the cardia C, it is quickly switched to the second illumination mode. At the time of this switching, the light amount of the broadband light BB may be gradually increased according to the degree of recognition.

  Returning to FIG. 6, in parallel with the display of the observation image 66b, the part discriminating unit 57 analyzes the special light image data newly stored in the frame memory 56 to discriminate the type of the part to be observed. The result is sent to the CPU. When the region determination unit 57 determines that the region to be observed is cardia C, the illumination light is emitted under the second illumination mode, the special light image data is acquired, the observation image 66b is displayed, the region to be observed Is continuously executed.

  On the other hand, when the insertion portion 16 is further pushed into the back and the insertion portion distal end portion 16a reaches the inside of the stomach S, the inside of the stomach S is dark, so the area of the dark portion BL in the observation image 66b increases rapidly. To do. For this reason, the part discriminating unit 57 discriminates that the site to be observed is the stomach S when the area of the dark part BL is equal to or larger than the predetermined area upper limit value, and sends the discrimination result to the CPU 54.

  The emission control unit 63 refers to the data table 61 based on the determination result of the part determination unit 57 and determines the observation mode to be the third illumination mode, and to the light source drive control unit 37, the light amount ratio (Bn: A third illumination mode switching command including information of BB = 1: 2) is issued.

  The light source drive control unit 37 receives the third illumination mode switching command from the emission control unit 63 and controls the diaphragms 34a and 34b to control the blue LD 31 and the broadband light source 30 so that the light quantity ratio Bn: BB = 1: 2. The amount of emitted light is controlled. Thereby, mixed light (hereinafter referred to as third mixed light) Bn and BB of the B narrowband light Bn and the broadband light BB having a light amount ratio of 1: 2 is irradiated into the stomach S.

  The third mixed light Bn and BB reflected / scattered inside the stomach S enters the CCD 44 through the observation window 19 and the like. Thereby, the special light image data is generated and stored in the frame memory 56 as in the first to second illumination modes.

  When the new special light image data is stored in the frame memory 56 and the observation mode is the third illumination mode, the display control unit 64 sends the display control circuit 58 to the display control circuit 58 based on the reference result of the data table 61. In response, a normal allocation display command is issued.

  As shown in FIG. 12, the display control circuit 58 receives the normal assignment display command from the display control unit 64, reads the special light image data newly stored in the frame memory 56, and displays B, B of the special light image data. The pixel values of the three colors G and R are output to the B channel, G channel, and R channel of the monitor 14, respectively. Thereby, as shown in FIG. 13, an observation image 66 c of the stomach S is displayed on the monitor 14.

  In the third illumination mode, since the amount of the broadband light BB is increased compared to the first to second illumination modes, when the inside of the dark stomach S is observed, the observation image 66c may become dark and difficult to see. Is prevented. Further, by switching the color channel assignment to “normal assignment”, it is possible to observe the superficial blood vessels based on the bright normal observation image, so that it is possible to prevent the superficial blood vessels from becoming difficult to see even in the dark stomach S.

  Returning to FIG. 6, in parallel with the display of the observation image 66c, the part discriminating unit 57 analyzes the special light image data newly stored in the frame memory 56 to discriminate the type of the part to be observed. The result is sent to the CPU. If the region determination unit 57 determines that the region to be observed is the stomach S, the illumination light is emitted under the third illumination mode, the special light image data is acquired, the observation image 66c is displayed, the region to be observed Is continuously executed.

  On the other hand, when the region determination unit 57 determines that the region to be observed is cardia C or esophagus E, the above-described second illumination mode, emission of illumination light in the first illumination mode, acquisition of special light image data, observation image Is displayed and the part to be observed is determined. Thereby, when the insertion part 16 is extracted from the body of the patient H after observation of the stomach S, the special light observation mode is switched in the order of the third illumination mode, the second illumination mode, and the first illumination mode.

  Illumination emitted from the light source device 13 by changing the light quantity ratio of the B narrowband light Bn and the broadband light BB according to the type of the observation site irradiated with the illumination light from the insertion portion distal end portion 16a during the special light observation. Since the type of light is switched, the special light observation can be performed with the optimum illumination light according to the type of the observation site without the operator performing the illumination light switching operation. As a result, the operator's trouble can be saved.

[Second Embodiment]
Next, an endoscope system 70 according to a second embodiment of the present invention will be described with reference to FIG. In the endoscope system 10 of the first embodiment, the light amount ratio of the B narrowband light Bn and the broadband light BB is changed according to the type of the observation site. However, in the endoscope system 70, the first embodiment is changed. In the same manner as described above, the special light image data is subjected to different spatial frequency processing in accordance with the type of the observation site after changing the light amount ratio. Since the endoscope system 70 has the same configuration as the endoscope system 10 of the first embodiment except for the processor device 71, the same reference numerals are used for the same functions and configurations as those of the first embodiment. The description is omitted.

  The processor device 71 has basically the same configuration as the processor device 12 of the first embodiment. However, in the processor device 71, the CPU 72 functions as a spatial frequency processing unit (high-pass filter processing means, band-pass filter processing means) 73 in the special light observation mode, and a data table 74 is stored in the memory 53.

  The spatial frequency processing unit 73 refers to the data table 74 based on the determination result of the site to be observed by the site determination unit 57, and performs a predetermined spatial frequency processing for the special light image data stored in the frame memory 56. Apply one of the following. The spatial frequency processing includes a high-pass filter (HPF) process that emphasizes high-frequency components of special light image data, and a band-pass filter (Bandwidth-Pass) that emphasizes medium-frequency components within a specified range. Filter: BPF) processing. Since the spatial frequency processing is known, a specific description is omitted here.

  The data table 74 is basically the same as the data table 61 of the first embodiment, but further, the type of the site to be observed (esophagus E, cardia C, stomach S) includes “execution / non-execution” of spatial frequency processing and “Type” is stored in association with each other. Specifically, “HPF” is set in the first illumination mode for performing special light observation of the esophagus E, “BPF” is set in the second illumination mode for performing special light observation of the cardia C, and special light observation of the stomach S is performed. In the third illumination mode for performing “x”, “x” is set for not performing spatial frequency processing.

  The spatial frequency processing unit 73 performs HPF processing on the special light image data stored in the frame memory 56 in the first illumination mode in which the superficial blood vessels in the esophagus E are intensively observed. Since the edge of the superficial blood vessel is emphasized by the HPF process, the superficial blood vessel is highlighted more than in the first embodiment.

  In addition, the spatial frequency processing unit 73 performs BPF processing on the special light image data stored in the frame memory 56 in the second illumination mode in which the middle and deep blood vessels around the cardia C are intensively observed. Since the mid-depth blood vessel is emphasized by the BPF process, the mid-depth blood vessel is highlighted more than in the first embodiment. It should be noted that the range of the designated frequency of the BPF that can highlight the middle-deep blood vessel is determined by experiments, simulations, or the like.

  Since the processes other than performing the spatial frequency process on the special light image data in the first to second illumination modes are the same as those in the first embodiment, the description thereof is omitted here.

[Third Embodiment]
In the first embodiment, the light quantity ratio between the B narrowband light Bn and the broadband light BB is fixed in each of the first to third illumination modes. For example, as shown in FIG. By storing the data table 75 in the memory 53, the light amount ratio can be adjusted in each of the first to third illumination modes.

  The adjustment of the light quantity ratio may be performed manually by the operator stepwise using, for example, a foot switch 76 or the like, or according to the area of the dark part BL determined by the region determination unit 57, the density of the surface blood vessels and the middle-deep blood vessels The CPU 54 may perform this automatically. The adjustment range of the light amount ratio under each illumination mode is appropriately determined through experiments, simulations, or the like. Here, when the light amount ratio is adjusted using the foot switch 76, for example, in accordance with the number of switch operations, the light amount ratio is adjusted stepwise (0.5, 0.6,... 1) within the adjustable range. ., 0.5,...

  In the data table 75, the light quantity ratio is adjusted by adjusting the light quantity of the broadband light BB. However, the light quantity ratio is adjusted by adjusting the light quantity of the B narrow band light Bn or the light quantities of the two lights Bn and BB. Adjustments may be made. Similarly, in the second embodiment, the light amount ratio may be adjustable in each of the first to third illumination modes.

  In each of the above embodiments, the illumination mode is automatically switched according to the type of the observed region determined by the region determining unit 57. However, a manual switching mode for performing this switching manually may be provided separately.

  In each of the above embodiments, the CCD 44 of the 1CCD system is used as the color image sensor, but a so-called 3CCD system that includes three CCDs and a prism may be employed instead. In each of the above embodiments, each unit of the light source device is controlled by the CPU of the processor device. However, a control unit such as a CPU that controls these units may be provided in the light source device.

  In each of the embodiments described above, in the special light observation mode, mixed light of the B narrowband light Bn and the broadband light BB having different light quantity ratios according to the observation site is emitted from the light source device 13. Green narrowband light may be used instead of the broadband light BB. Further, the present invention can also be applied to a case where mixed light of three or more types of illumination light having different light quantity ratios is emitted according to the observation site.

  In each of the above embodiments, the upper digestive tract from the esophagus E to the stomach S has been described as an example of the site to be observed. However, for example, the present invention is also applied to an endoscope system that observes various sites to be observed in the body. Can be applied.

  The part discriminating unit 57 in each of the above embodiments discriminates the type of the observed part irradiated with the illumination light by analyzing the special light image data, but discriminates the kind of the observed part using various methods. May be. For example, the type of the site to be observed can be determined based on the detection result of the PH of the site to be observed (see Japanese Patent No. 3321235). Further, the type of the site to be observed can also be determined using various position detection methods for detecting the position of the insertion portion distal end portion 16a in the patient body, for example, using a computed tomography (CT) apparatus. Further, the type of the site to be observed may be determined by simple pattern recognition such as the shape inside the esophagus E and stomach S or the shape of the cardia C.

  In each of the above embodiments, the broadband light BB and the B narrowband light Bn are emitted from the light source device 13 to the electronic endoscope 11. You may provide in 16a.

  In each of the above-described embodiments, the endoscope system that performs special light observation of the surface blood vessels and the middle and deep blood vessels has been described as an example. However, fluorescence observation (Auto Fluorescence Imaging) that uses light of a specific wavelength is described. The present invention can be applied to an endoscope system used for various special light observations such as infrared light observation (Infra Red Imaging) and photodynamic diagnosis.

DESCRIPTION OF SYMBOLS 10,70 Endoscopy system 11 Electronic endoscope 12,71 Processor apparatus 13 Light source apparatus 14 Monitor 30 Broadband light source 31 Blue LD
34a, 34b Aperture 37 Light source drive controller 54, 72 CPU
57 part discriminating unit 58 display control circuit 61, 74, 75 data table 63 emission control unit 64 display control unit 73 spatial frequency processing unit

Claims (10)

A light source that emits narrowband and broadband light;
A first illumination mode in which the amount of light of the narrowband light is increased from the amount of light of the broadband light; a second illumination mode in which the amount of light of the narrowband light and the amount of light of the broadband light are substantially equal; and the narrowband light A light source control means for controlling the light source so as to emit light in any one of the illumination modes of the third illumination mode in which the amount of light is reduced from the amount of light of the broadband light;
An endoscope that has an insertion portion that is inserted into a subject, and that irradiates the observation site in the subject from the distal end portion of the insertion portion with the narrowband light and the broadband light emitted from the light source;
The first blood vessel highlighted by the narrow-band light of the narrow-band light and the broadband light, and the first blood vessel highlighted by the broadband light of the narrow-band light and the broadband light, than the first blood vessel Imaging means for imaging an image of the second blood vessel in the deep part to obtain an observation image;
Analyzing the image data of the observation image to obtain the density of the first blood vessels, the density of the second blood vessels, and the area of the dark part , wherein the density of the first blood vessels is an upper limit value or more, Further, when the area of the dark part is not less than the lower limit value and less than the upper limit value, light is emitted in the first illumination mode, the density of the second blood vessels is not less than the upper limit value, and the area of the dark part is the lower limit value. And a processor device that controls the light source control means so as to emit light in the second illumination mode . It said processor device, when the area of the dark portion is more than the upper limit value, the third endoscope according to claim 1, wherein the controller controls the light source control means so as to emit light in the illumination mode system. A monitor for displaying the observation image;
Display control means for outputting R, G, B pixel values of the observation image to a predetermined channel according to the type of the illumination mode among the R, G, B channels of the monitor. The endoscope system according to claim 1 or 2 . Wherein the display control unit, the first to the second illumination mode the B the pixel value B, and outputs the G channel, according to claim 3, characterized in that outputs the G pixel value to the R channel Endoscope system. Wherein the display control unit, the third said the illumination mode R, G, endoscope system according to claim 3 or 4, wherein the outputs B pixel values the respective R, G, and B channels. Wherein the first illumination mode, the image data of the observation image, 5 or claims 1, characterized in that it comprises a high-pass filter processing means for performing emphasize high-pass filtering the high frequency component The endoscope system according to claim 1. The band-pass filter processing means for performing band-pass filter processing for emphasizing a medium frequency component within a predetermined range with respect to image data of the observation image in the second illumination mode. The endoscope system according to any one of 1 to 6 . The endoscope system according to any one of claims 1 to 7 , wherein the narrow-band light is blue narrow-band light having a wavelength corresponding to an absorption peak of an absorption spectrum of hemoglobin light. The endoscope system according to any one of claims 1 to 8 , wherein the broadband light is green light having a wavelength of about 500 nm to 600 nm. A light source emitting narrowband and broadband light;
A light source control unit configured to increase a light amount of the narrowband light from a light amount of the broadband light; and a second illumination mode in which the light amount of the narrowband light and the light amount of the broadband light are substantially equal. Controlling the light source to emit light in any one of the illumination modes of the third illumination mode in which the light amount of the narrowband light is reduced from the light amount of the broadband light;
The imaging means is highlighted with the first blood vessel highlighted with the narrowband light of the narrowband light and the broadband light, and highlighted with the broadband light of the narrowband light and the broadband light, Imaging a second blood vessel deeper than one blood vessel to obtain an observation image;
A processor device analyzing image data of the observation image to obtain a density of the first blood vessels, a density of the second blood vessels, and an area of a dark part ;
The processor device emits light in the first illumination mode when the density of the first blood vessel is equal to or higher than an upper limit value and the area of the dark portion is equal to or higher than a lower limit value and lower than the upper limit value, and the second illumination mode And controlling the light source control means to emit light in the second illumination mode when the density of blood vessels is equal to or higher than the upper limit value and the area of the dark portion is less than the lower limit value. The operation method of the endoscope system.

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