JP2011161008A - Electronic endoscope system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic endoscope system capable of capturing the image of a subject with brightness sufficient for the diagnosis in the range of wavelengths of light of weakened intensity radiated from a xenon lamp or the like. <P>SOLUTION: The electronic endoscope system includes: a first light source for radiating the light of a prescribed wavelength; a second light source for radiating the light in the range of weakened intensities of the first light source at a higher intensity than the first light source; light combining means for combining the light radiated from the first light source with the light radiated from the second light source; an irradiation optical system for irradiating the subject with the combined light; a color solid imaging element for receiving the light reflected from the irradiated subject; and image generating means for processing an imaging signal output from the solid imaging element and generating a color image displayed in a monitor. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electronic endoscope system for observing a color image of a subject, and more specifically, to allow an operator to observe biological information in a wavelength range, which has been apt to be lost, with sufficient brightness. The present invention relates to a suitable electronic endoscope system.

  As a system for diagnosing the inside of a body cavity of a patient, an electronic endoscope system is generally known and put into practical use. A general electronic endoscope system includes a white light source such as a xenon lamp in order to capture a color image by irradiating a body cavity where natural light does not reach.

  A specific configuration example of an electronic endoscope system equipped with a xenon lamp is described in Patent Document 1. In the electronic endoscope system described in Patent Document 1, white light emitted from a xenon lamp is sequentially limited to R light, G light, and B light, and an object is irradiated through a light guide, and reflected light of each wavelength. A so-called frame sequential method is used in which a color image is obtained by synthesizing these images.

Japanese Unexamined Patent Publication No. 64-43227

  By the way, it is ideal that the light irradiating the subject has high intensity over the entire wavelength range necessary for photographing the anatomy. However, the spectral characteristics of this type of xenon lamp combined with a light guide do not have high intensity in all the wavelength ranges necessary for imaging of the anatomy. In general, for example, the strength is greatly reduced in a short wavelength region around 400 nm. In this way, it is difficult to obtain a subject image having sufficient brightness for diagnosis in the low-intensity wavelength region, and it is pointed out that necessary biological information may be missing.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to obtain a subject image having sufficient brightness sufficient for diagnosis even in a wavelength region where the intensity of light emitted from a xenon lamp or the like is reduced. It is to provide an electronic endoscope system that can be obtained.

  An electronic endoscope system according to an aspect of the present invention that solves the above problems includes a first light source that emits light in a predetermined wavelength range, and light in a fall region of the first light source. A second light source that emits light with a higher intensity than the light source, an optical coupling unit that couples light emitted from the first and second light sources, and an irradiation optical system that irradiates the subject with the combined light, A color solid-state imaging device that receives reflected light from the irradiated subject, and an image generation unit that processes an imaging signal output from the solid-state imaging device and generates a color image that can be displayed on a monitor. Features.

  According to the electronic endoscope system of the present invention, since the irradiation light amount of the first light source in the depressed area is supplemented by the second light source, which is another light source, the biological information of the depressed area that has been apt to be lost conventionally. Can be observed by the operator with sufficient brightness.

  As the first light source, for example, an incandescent bulb, a discharge lamp or the like is assumed. For example, a laser light source is assumed as the second light source.

  The light in the predetermined wavelength region is light including at least a visible light region, for example. The wavelength range of light emitted from the second light source is, for example, a wavelength suitable for absorption of hemoglobin. A wavelength suitable for absorption of hemoglobin is, for example, around 400 nm or around 550 nm.

  An electronic endoscope system according to the present invention includes an optical filter that restricts light emitted from a first light source to a specific wavelength region, and an optical filter inserted in an irradiation light path between the first light source and the optical coupling means. Or an optical filter switching means for retracting or retracting. The electronic endoscope system according to the present invention may further include an operation unit that receives an input operation by a user. In this case, the optical filter switching means inserts the optical filter into the irradiation optical path or retracts from the irradiation optical path in accordance with the input operation received by the operation means.

  ADVANTAGE OF THE INVENTION According to this invention, the electronic endoscope system which can obtain the to-be-photographed object image suitable for a diagnosis is provided also in the wavelength range where the intensity | strength has fallen among the lights which the xenon lamp etc. emitted.

1 is an external view of an electronic endoscope system according to an embodiment of the present invention. It is a block diagram which shows the structure of the electronic endoscope system of embodiment of this invention. It is a figure which shows the spectral characteristic of each light source of embodiment of this invention. It is a figure which shows the spectral characteristic of the light irradiated to a to-be-photographed object in embodiment of this invention. It is a figure which shows the spectral characteristic of the light irradiated to a to-be-photographed object by another embodiment.

  Hereinafter, an electronic endoscope system according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an external view of an electronic endoscope system 1 according to the present embodiment. As shown in FIG. 1, the electronic endoscope system 1 includes an electronic scope 100 for photographing a subject. The electronic scope 100 includes a flexible tube 11 covered with a flexible sheath (outer skin) 11a. Connected to the distal end of the flexible tube 11 is a distal end portion 12 that is sheathed by a rigid resin casing. The bending portion 14 at the connecting portion between the flexible tube 11 and the distal end portion 12 is remotely operated from the hand operating portion 13 connected to the proximal end of the flexible tube 11 (specifically, the rotation of the bending operation knob 13a). The operation is flexible. This bending mechanism is a well-known mechanism incorporated in a general electronic scope, and is configured to bend the bending portion 14 by pulling the operation wire in conjunction with the rotation operation of the bending operation knob 13a. When the direction of the distal end portion 12 changes according to the bending operation by the above operation, the imaging region by the electronic scope 100 moves.

  As shown in FIG. 1, the electronic endoscope system 1 has a processor 200. The processor 200 is an apparatus that integrally includes a signal processing device that processes a signal from the electronic scope 100 and a light source device that irradiates a body cavity that does not reach natural light through the electronic scope 100. In another embodiment, the signal processing device and the light source device may be configured separately.

  The processor 200 is provided with a connector portion 20 corresponding to the connector portion 10 provided at the proximal end of the electronic scope 100. The connector unit 20 has a coupling structure corresponding to the connector unit 10 and is configured to electrically and optically connect the electronic scope 100 and the processor 200.

  FIG. 2 is a block diagram showing a configuration of the electronic endoscope system 1. As shown in FIG. 2, the electronic endoscope system 1 includes a monitor 300 connected to the processor 200 via a predetermined cable. In FIG. 1, the monitor 300 is not shown in order to simplify the drawing.

  As illustrated in FIG. 2, the processor 200 includes a system controller 202 and a timing controller 204. The system controller 202 controls each element constituting the electronic endoscope system 1. The timing controller 204 outputs a clock pulse for adjusting the signal processing timing to various circuits in the electronic endoscope system 1.

  The lamp 208 emits light (or light including at least the visible light region) having a spectrum that mainly extends from the visible light region to the invisible infrared light region after being started by the lamp power igniter 206. As the lamp 208, a high-intensity lamp (an incandescent lamp or a discharge lamp) such as a xenon lamp, a halogen lamp, or a metal halide lamp is suitable. Irradiation light emitted from the lamp 208 is limited by the condenser lens 210 to an appropriate amount of light through the diaphragm 212 while being condensed.

  A motor 214 is mechanically connected to the diaphragm 212 via a transmission mechanism such as an arm or a gear (not shown). The motor 214 is a DC motor, for example, and is driven under the drive control of the driver 216. The diaphragm 212 is operated by the motor 214 to change the opening degree so that the image displayed on the monitor 300 has an appropriate brightness, and limits the amount of light emitted from the lamp 208 according to the opening degree. . The appropriate reference for the brightness of the image is changed according to the brightness adjustment operation of the front panel 218 by the operator. Note that the dimming circuit that controls the brightness by controlling the driver 216 is a well-known circuit and is omitted in this specification.

  Various forms of the configuration of the front panel 218 are assumed. As a specific configuration example of the front panel 218, a hardware key for each function mounted on the front surface of the processor 200, a touch panel GUI (Graphical User Interface), a combination of a hardware key and a GUI, and the like are assumed. .

  The irradiation light that has passed through the diaphragm 212 is split by the optical filter 213 and enters the optical coupler 217. A motor 215 driven under the drive control of the driver 216 is mechanically coupled to the optical filter 213 via a transmission mechanism such as an arm or a gear (not shown). In FIG. 2, the connection between the motor 215 and the driver 216 is omitted for the sake of simplicity. The motor 215 inserts the optical filter 213 into the optical path or retracts it from the optical path in accordance with the switching operation of the front panel 218 by the operator. During the period when the optical filter 213 is retracted from the optical path, the irradiation light that has passed through the diaphragm 212 is directly incident on the optical coupler 217.

  FIG. 3A is a diagram showing the spectral characteristics of the irradiation light before being emitted from the lamp 208 and entering the optical coupler 217. In FIG. 3A, the vertical axis represents normalized intensity, and the horizontal axis represents wavelength (unit: nm). In other spectral characteristic diagrams other than FIG. 3A, the vertical axis represents intensity and the horizontal axis represents wavelength. The solid line in FIG. 3A indicates the spectral characteristics of the irradiation light incident on the optical coupler 217 without passing through the optical filter 213, and the broken line indicates the irradiation light incident on the optical coupler 217 through the optical filter 213. Spectral characteristics are shown. Hereinafter, for convenience of explanation, the light having the former spectral characteristic is referred to as “non-band-limited light”, and the light having the latter spectral characteristic is referred to as “band-limited light”.

  As shown in FIG. 3A, the non-band limited light has an intensity over a range from the visible light region to the infrared light region (for example, 380 nm to 1000 nm). However, on the end side of the distribution range (for example, a short wavelength region near 400 nm or a long wavelength region near 1000 nm), the intensity drop is large, and for example, the intensity is less than half the maximum of the highest intensity among the non-band limited light . For this reason, there is a problem that it is difficult to obtain a subject image having sufficient brightness for diagnosis in the wavelength region on the end side of the distribution range. In the present specification, a wavelength region having a half intensity or less with respect to the highest intensity among the irradiation light of the lamp 208 is referred to as a “sag region”.

  In order to solve such a problem, the processor 200 of this embodiment is provided with a light source separately from the lamp 208. Specifically, a laser light source 219 is mounted on the processor 200. The laser light source 219 is driven under the drive control of the driver 216 to output laser light having a predetermined wavelength. In FIG. 2, the connection between the laser light source 219 and the driver 216 is omitted for the sake of simplifying the drawing. Laser light output from the laser light source 219 enters the optical coupler 217. Here, FIG. 3B shows spectral characteristics of the laser light output from the laser light source 219. As shown in FIG. 3B, the laser beam has a peak in the vicinity of 400 nm. The separately mounted light source is not limited to a laser light source, and may be another type of light source such as an LED (Light Emitting Diode).

  The optical coupler 217 couples the irradiation light from the lamp 208 and the laser light from the laser light source 219 to the same optical path and emits them, and enters the incident end of an LCB (Light Carrying Bundle) 102. Irradiation light incident on the incident end of the LCB 102 propagates by repeating total reflection in the LCB 102. Irradiation light propagating through the LCB 102 is emitted from the emission end of the LCB 102 disposed at the tip of the electronic scope 100. Irradiation light emitted from the exit end of the LCB 102 irradiates the subject via the light distribution lens 104. The reflected light from the subject forms an optical image at each pixel on the light receiving surface of the solid-state image sensor 108 via the objective lens 106.

  The solid-state image sensor 108 is, for example, a single-plate color CCD (Charge Coupled Device) image sensor, and accumulates an optical image formed by each pixel on the light receiving surface as charges corresponding to the amount of light. It converts into the imaging signal according to each color. The converted imaging signal is output to the signal processing circuit 220 via the driver signal processing circuit 112 after signal amplification by the preamplifier 110. In another embodiment, the solid-state image sensor 108 may be a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

  The driver signal processing circuit 112 accesses the memory 114 and reads unique information of the electronic scope 100. The unique information of the electronic scope 100 includes, for example, the number of pixels and sensitivity of the solid-state image sensor 108, a compatible rate, a model number, and the like. The driver signal processing circuit 112 outputs the unique information read from the memory 114 to the system controller 202.

  The system controller 202 performs various calculations based on the unique information of the electronic scope 100 and generates a control signal. The system controller 202 uses the generated control signal to control the operation and timing of various circuits in the processor 200 so that processing suitable for the electronic scope connected to the processor 200 is performed. The system controller 202 may be configured to have a table in which a model number of the electronic scope is associated with control information suitable for the electronic scope of this model number. In this case, the system controller 202 refers to the control information in the correspondence table, and controls the operation and timing of various circuits in the processor 200 so that processing suitable for the electronic scope connected to the processor 200 is performed.

  The timing controller 204 supplies clock pulses to the driver signal processing circuit 112 in accordance with timing control by the system controller 202. The driver signal processing circuit 112 drives and controls the solid-state imaging device 108 at a timing synchronized with the frame rate of the video processed on the processor 200 side in accordance with the clock pulse supplied from the timing controller 204.

  The image processing signal from the driver signal processing circuit 112 is input to the signal processing circuit 220. The image pickup signal is subjected to processing such as clamping, knee, γ correction, interpolation processing, AGC (Auto Gain Control), AD conversion, and the like, and then is stored in a frame memory (not shown) for each color of R, G, B for each color signal. Buffered. Each buffered color signal is swept from the frame memory at a timing controlled by the timing controller 204, and converted into a video signal conforming to a predetermined standard such as NTSC (National Television System Committee) or PAL (Phase Alternating Line). Converted. By sequentially inputting the converted video signals to the monitor 300, an image of the subject is displayed on the display screen of the monitor 300.

  FIG. 4 is a diagram showing the spectral characteristics of the light applied to the subject. More specifically, FIG. 4A shows the spectral characteristics of the irradiation light during the period in which the optical filter 213 is retracted from the optical path. As shown in FIG. 4A, the irradiation light has a spectral characteristic in which the non-band-limited light and the laser light are superimposed while the optical filter 213 is retracted from the optical path. Note that changes in the spectral characteristics of the irradiated light by the LCB 102 and the light distribution lens 104 are negligible. Therefore, in FIG. 4, the change is not taken into consideration for convenience of explanation.

  As shown in FIG. 4A, the peak of the laser light compensates for the drop region on the short wavelength side (near 400 nm) of the non-band-limited light. Therefore, during the period when the optical filter 213 is retracted from the optical path, a subject image with sufficient intensity can be obtained over a wide wavelength range from the visible light region including the short wavelength region near 400 nm to the vicinity of the infrared light region. . Note that the vicinity of 400 nm corresponding to the peak of the laser beam is a band that is easily absorbed by hemoglobin. Therefore, on the display screen of the monitor 300, for example, blood vessels that tend to be lost in a normal color observation image are clearly displayed together with the mucous membrane structure of a living body, for example.

  FIG. 4B shows the spectral characteristics of the irradiated light during the period when the optical filter 213 is inserted in the optical path. As shown in FIG. 4B, the irradiation light has spectral characteristics in which the band-limited light and the laser light are superimposed during the period when the optical filter 213 is inserted in the optical path. The band-limited light has a peak in the vicinity of, for example, 680 nm and has a wide half-value width as compared with the laser light.

  During the period when the optical filter 213 is inserted in the optical path, the irradiation light of the lamp 208 is limited as compared with the case of FIG. Therefore, the detection sensitivity with respect to a specific biological structure becomes high. Specifically, blood vessels in the living body are highlighted by laser light that is narrow band light. However, as shown in FIG. 4B, band-limited light having a gentle peak is also seen near the red region (around 680 nm). Therefore, on the display screen of the monitor 300, the mucous membrane structure of a living body having a lot of red components and the highlighted blood vessel are simultaneously displayed on one screen.

  Comparing the spectral characteristics of FIG. 4A and FIG. 4B, when it is desired to observe a biological structure in a wider wavelength range, the optical filter 213 is inserted into the optical path and the blood vessel is observed more clearly. In this case, it is assumed that the optical filter 213 is retracted from the optical path.

  As described above, according to the electronic endoscope system 1 of the present embodiment, the fallen area of the irradiation light of the lamp 208 tends to be lost by compensating for the laser light of the laser light source 219 which is another light source. These blood vessels can be clearly observed together with other anatomy.

  The above is the description of the embodiment of the present invention. The present invention is not limited to the above-described configuration, and various modifications can be made within the scope of the technical idea of the present invention. For example, as shown in FIG. 3A, the intensity of the lamp 208 is greatly reduced even in the infrared region near 1000 nm. The processor 200 according to another embodiment may be configured to include a laser light source that outputs a laser beam having a wavelength near 1000 nm in order to compensate for the sagging region.

  FIG. 5 is a diagram showing the spectral characteristics of light irradiated to a subject in still another embodiment. In such an embodiment, laser light having a peak near 550 nm and lamp light having an intensity of about half the value of the peak are superimposed over the range from the visible light region to the infrared light region. By suppressing the intensity of the lamp light with respect to the laser light, a decrease in detection sensitivity with respect to a specific biological structure is effectively suppressed. The vicinity of 550 nm corresponding to the peak of the laser beam is a band that is easily absorbed by hemoglobin. Therefore, on the display screen of the monitor 300, the mucous membrane structure of the living body and the like are simultaneously displayed on one screen together with the highlighted blood vessel.

DESCRIPTION OF SYMBOLS 1 Electronic endoscope system 100 Electronic scope 200 Processor 213 Optical filter 217 Optical coupler 219 Laser light source 220 Signal processing circuit

Claims (5)

A first light source that emits light in a predetermined wavelength range;
A second light source that emits light in a fall region of the first light source with a higher intensity than the first light source;
An optical coupling means for coupling light emitted from the first and second light sources;
An irradiation optical system for irradiating a subject with the combined light;
A color solid-state imaging device that receives reflected light from the irradiated subject;
Image generation means for generating a color image that can be displayed on a monitor by processing an imaging signal output from the solid-state imaging device;
An electronic endoscope system comprising:   The electronic endoscope system according to claim 1, wherein the first light source is an incandescent bulb or a discharge lamp, and the second light source is a laser light source.   The light of the predetermined wavelength region includes at least a visible light region, and the wavelength region of light emitted by the second light source is a wavelength suitable for absorption of hemoglobin. Item 3. The electronic endoscope system according to Item 2. An optical filter that limits light emitted from the first light source to a specific wavelength range;
Optical filter switching means for inserting or retracting the optical filter in an irradiation optical path between the first light source and the optical coupling means;
The electronic endoscope system according to any one of claims 1 to 3, further comprising: It further has an operation means for receiving an input operation by the user,
5. The electronic endoscope according to claim 4, wherein the optical filter switching unit inserts or retracts the optical filter into the irradiation light path according to an input operation received by the operation unit. system.

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