JP6514155B2 - Electronic endoscope system and light source device for endoscope - Google Patents

Description

  The present invention relates to an electronic endoscope system for observing a color image of an object and a light source device for an endoscope, and more specifically, an electronic endoscope suitable for causing an operator to observe a specific biological structure The present invention relates to a system and a light source device for an endoscope.

  As a system for diagnosing a patient's body cavity, an electronic endoscope system is generally known and put to practical use. In the electronic endoscope system, in order to view tissue information of a specific biological structure, the subject is illuminated through a narrow band filter that transmits light in a wavelength range having high absorption characteristics to the specific biological structure, It is known to have a function of receiving a scattered component to generate a spectral image that emphasizes a specific biological structure.

  Patent Document 1 describes an example of an endoscope apparatus that performs such observation with narrow band light. In the endoscope apparatus described in Patent Document 1, a narrow band filter for limiting a band of at least one or more wavelength regions of illumination light is disposed on an optical path from the illumination light supply unit to the imaging unit, A band image of a discrete spectral distribution of an object obtained by light in a band is formed on an imaging means. By using such an endoscope apparatus, it is possible to separate and view tissue information of a specific biological structure of a subject at a layer level, and obtain desired deep tissue information near the tissue surface of the biological structure. be able to.

Patent No. 3583731

  However, in the endoscope apparatus described in Patent Document 1, since the illumination light has a discrete spectral distribution, information can not be obtained in wavelength regions other than the transmitted main wavelength, and the information is lost. There is a possibility of In addition, it is pointed out that the light transmission area of the illumination light is limited by the narrow band filter, so that the light quantity decreases and the brightness of the obtained image becomes dark.

  The present invention has been made in view of the above circumstances, and the purpose of the present invention is to prevent loss of information when observing a specific biological structure with narrow band light, and also to control the brightness and contrast of the image. It is an object of the present invention to provide an electronic endoscope system and an endoscope light source device capable of improving the

  An electronic endoscope system according to an aspect of the present invention, which solves the above-mentioned problems, comprises a light source emitting light including a visible light region, and at least two specific wavelengths in a continuous wavelength range including the visible light region. Having a transmission peak, having a transmittance higher than 0 and lower than a half value of the transmission peak between the transmission peaks of the at least two specific wavelengths, in a wavelength range other than between the transmission peaks of at least two specific wavelengths An optical filter having a transmittance of 0, a color solid-state imaging device for receiving reflected light from a subject illuminated by illumination light through the optical filter, and a processing signal for monitoring an imaging signal output from the solid-state imaging device And image generation means for generating a displayable color image.

  When a subject is illuminated through the optical filter according to the present invention, a spectral image with improved brightness and contrast can be generated and displayed on the display screen of the monitor. Furthermore, since information in the wavelength region between transmission peaks of a specific wavelength can be obtained, it is also possible to prevent loss of information.

  Further, the at least two specific wavelengths may include around 420 nm, which is a band in which the absorption of hemoglobin is large. This makes it possible to observe the vascular structure near the surface layer and deep layer.

  The electronic endoscope system of the present invention may further include optical filter switching means for inserting or retracting the optical filter in the irradiation light path of the light source, and operation means for receiving an input operation by the user. Furthermore, the optical filter switching means may insert the optical filter into the irradiation light path or retract it from the irradiation light path according to the input operation received by the operation means. Thus, by retracting the optical filter from the irradiation light path as necessary, it becomes possible to display a normal color image on the display screen.

  Furthermore, according to the present invention, a light source emitting light including a visible light range, and a transmission peak at at least two specific wavelengths in a continuous wavelength range including the visible light range, the transmission of the at least two specific wavelengths An optical filter having a transmittance between peak and lower than half of the transmission peak and having a transmittance of 0 in a wavelength range other than between transmission peaks of at least two specific wavelengths. There is provided a light source device for an endoscope characterized by

  According to the present invention, an electronic endoscope system capable of preventing loss of information and improving the brightness and contrast of an image when observing a specific biological structure with narrow band light, and a light source for an endoscope An apparatus is provided.

FIG. 1 is an external view of an electronic endoscope system according to an embodiment of the present invention. It is a block diagram showing composition of an electronic endoscope system of an embodiment of the present invention. It is a figure which shows the spectral characteristic of the optical filter which the processor of embodiment of this invention has. It is a figure which shows each observation image at the time of irradiating a to-be-photographed object, the case where it irradiates with a to-be-photographed object via the optical filter 213, and via no. It is a figure which shows the spectral characteristic of the optical filter which the processor of another embodiment has.

  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 the electronic endoscope system 1 of the present embodiment. As shown in FIG. 1, the electronic endoscope system 1 includes an electronic scope 100 for capturing an object. The electronic scope 100 includes a flexible tube 11 covered by a flexible sheath (skin) 11a. The distal end portion 12, which is packaged by a rigid resin casing, is connected to the distal end of the flexible tube 11. The bending portion 14 at the connection point between the flexible tube 11 and the distal end portion 12 performs remote control from the hand operation portion 13 connected to the proximal end of the flexible tube 11 (specifically, rotation of the bending operation knob 13a Operation) is configured to be flexible. This bending mechanism is a known mechanism incorporated in a general electronic scope, and is configured to bend the bending portion 14 by pulling of the operation wire interlocked with the rotation operation of the bending operation knob 13a. By changing the direction of the tip 12 according to the bending operation by the above operation, the imaging region by the electronic scope 100 is moved.

  As shown in FIG. 1, the electronic endoscope system 1 includes a processor 200. The processor 200 is a device integrally including a signal processing device that processes a signal from the electronic scope 100 and a light source device that illuminates a body cavity to which natural light does not reach via 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 connection 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 the configuration of the electronic endoscope system 1. As shown in FIG. 2, the electronic endoscope system 1 has a monitor 300 connected to the processor 200 via a predetermined cable. In FIG. 1, the monitor 300 is not shown to simplify the drawing.

  As shown in FIG. 2, the processor 200 includes a system controller 202 and a timing controller 204. The system controller 202 controls each of the elements constituting the electronic endoscope system 1. The timing controller 204 outputs clock pulses for adjusting 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 extending mainly from the visible light region to the infrared light region which is invisible after being started by the lamp power igniter 206. As the lamp 208, a high-intensity lamp such as a xenon lamp, a halogen lamp, or a metal halide lamp is suitable. The irradiation light emitted from the lamp 208 is condensed by the condenser lens 210 and limited to an appropriate light amount through the stop 212.

  A motor 214 is mechanically connected to the aperture 212 via a transmission mechanism such as an arm or gear (not shown). The motor 214 is, for example, a DC motor, 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 in order to set the image displayed on the monitor 300 to an appropriate brightness, and limits the light quantity of the light emitted from the lamp 208 according to the opening degree. . The reference of the brightness of the image to be appropriate is changed in accordance with the brightness adjustment operation of the front panel 218 by the operator. The light control circuit that controls the driver 216 to perform the brightness adjustment is a known circuit, and is omitted in the present specification.

  Various forms of the configuration of the front panel 218 are conceivable. 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 illumination light that has passed through the stop 212 is split by the optical filter 213 and enters the incident end of a light carrying bundle (LCB) 102. A motor 215 driven under the drive control of the driver 216 is mechanically connected to the optical filter 213 via a transmission mechanism such as an arm or a gear (not shown). The motor 215 inserts the optical filter 213 into the optical path or retracts the optical filter 213 from the optical path according to the switching operation of the front panel 218 by the operator. During a period in which the optical filter 213 is retracted from the light path, the irradiation light that has passed through the stop 212 is directly incident on the incident end of the LCB 102. As the motor 215, for example, a galvano motor, a servomotor or the like is assumed.

  The irradiation light incident on the incident end of the LCB 102 is propagated by repeating total reflection in the LCB 102. The irradiation light propagated in the LCB 102 is emitted from the emission end of the LCB 102 disposed at the tip of the electronic scope 100. The illumination light emitted from the emission end of the LCB 102 illuminates the subject via the light distribution lens 104. Reflected light from the subject forms an optical image at each pixel on the light receiving surface of the solid-state imaging device 108 via the objective lens 106.

  The solid-state imaging device 108 is, for example, a single-plate color CCD (Charge Coupled Device) image sensor, which accumulates an optical image formed by each pixel on the light receiving surface as an electric charge according to the light amount. It converts into an imaging signal according to each color. The converted imaging signal is amplified by the preamplifier 110 and then output to the signal processing circuit 220 through the driver signal processing circuit 112. In another embodiment, the solid-state imaging device 108 may be a complementary metal oxide semiconductor (CMOS) image sensor.

  The driver signal processing circuit 112 accesses the memory 114 to read the 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 imaging device 108, a compatible rate, and a model number. 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 operations based on the unique information of the electronic scope 100 to generate a control signal. The system controller 202 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 using the generated control signal. The system controller 202 may be configured to have a table in which the model number of the electronic scope and the control information suitable for the electronic scope of this model number are associated. In this case, the system controller 202 refers to the control information in the correspondence table to control the operation and timing of various circuits in the processor 200 such 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 timing synchronized with the frame rate of the image processed on the processor 200 side according to the clock pulse supplied from the timing controller 204.

  An imaging signal from the driver signal processing circuit 112 is input to the signal processing circuit 220. The image pickup signal is processed for each color signal in frame units for R, G and B colors (not shown) for each color signal after processing such as clamp, knee, γ correction, interpolation processing, AGC (Auto Gain Control) and AD conversion. Buffered. The buffered color signals are swept out of the frame memory at a timing controlled by the timing controller 204, and are converted into video signals conforming to a predetermined standard such as National Television System Committee (NTSC) or Phase Alternating Line (PAL). It is converted. By sequentially inputting the converted video signal to the monitor 300, the image of the subject is displayed on the display screen of the monitor 300. Here, during a period in which the optical filter 213 is inserted in the optical path to illuminate the subject, a specific biological structure is emphasized (for example, blood vessels are separated by layer structure (the color of blood vessels in the surface layer and deep layer are different) An image is generated and displayed. In addition, a normal color image is generated and displayed during a period in which the optical filter 213 is retracted from the optical path to illuminate the subject. In addition, in the case of generating a spectral image, color conversion processing different from that in the case of generating a normal color image is performed.

  FIG. 3 is a diagram showing the spectral characteristics of the optical filter 213. As shown in FIG. The vertical axis in FIG. 3 indicates normalized transmittance, and the horizontal axis indicates wavelength (unit: nm). As shown in FIG. 3, the spectral characteristics of the optical filter 213 have transmission peaks near 420 nm, 550 nm, and 650 nm, and have a predetermined or higher transmittance between the transmission peaks.

  The certain or higher transmittance between each transmission peak is higher than 0 and lower than the half value of each transmission peak. In the present embodiment, the transmittance of light other than the light of the specific wavelength for emphasizing the specific biological structure is intentionally made higher than 0 to suppress the light quantity cut by the optical filter 213 and thereby the brightness of the spectral image. At the same time, it is possible to obtain information between transmission peaks, and to prevent information loss. Furthermore, by setting the transmittance to be lower than the half value of each transmission peak, the decrease in detection sensitivity for a specific biological structure is also effectively suppressed. More preferably, the lower limit of the transmittance between each transmission peak is 5% or more of each transmission peak value, and the upper limit is 10% or less of each transmission peak. With such transmittance, an image with high contrast can be obtained while maintaining a certain degree of brightness.

  Furthermore, in the optical filter 213 of the present embodiment, the transmittance of the wavelength region other than between the transmission peaks is zero. This makes it possible to eliminate unnecessary red components as compared to the case where the transmittance is constant over the entire range from the visible light region to the infrared light region (for example, 380 nm to 1000 nm), and an image with higher contrast is obtained. It becomes possible to obtain. That is, according to the present embodiment, by irradiating the subject through the optical filter 213, a spectral image with improved brightness and contrast can be generated and displayed on the display screen of the monitor 300, and information can be displayed. It becomes possible to prevent that it is missing.

  FIG. 4A shows an observation image in the case where the subject is irradiated without passing through the optical filter 213, and FIG. 4B shows an observation image in the case where the subject is irradiated through the optical filter 213. The images shown in FIGS. 4A and 4B are obtained by imaging the same subject (in the oral cavity). When the optical filter 213 is not used, as shown in FIG. 4A, the mucous membrane structure in the oral cavity is observed as a brighter image. Because the specific anatomical structure is not emphasized, the image is generally flat. In the case of the optical filter 213, as shown in FIG. 4 (b), while the specific biological structure is emphasized, the mucous membrane structure in the oral cavity together with the specific biological structure is a bright image on one screen It is observed. The vicinity of 420 nm or 550 nm corresponding to the transmission peak is a band which is easily absorbed by hemoglobin, and the band near 420 nm is apt to be absorbed more than 550 nm. Therefore, the specific anatomy observed here is a blood vessel in the oral cavity. In addition, even when the light passes through the optical filter 213, since the irradiation light is not narrow band light but light in a wide wavelength range to some extent, loss of information can be prevented, and various types of light depending on the depth of wavelength The observation of the biological structure becomes possible, and the diagnostic ability is improved.

  The above is the description of the embodiment of the present invention. The present invention is not limited to the above configuration, and various modifications are possible within the scope of the technical idea of the present invention. For example, the spectral characteristics of the optical filter 213 are not limited to those shown in FIG. 3, and are appropriately set according to the biological structure of the observation target. As such a spectral characteristic, for example, an optical filter 213 ′ shown in FIG. 5 and the like can be mentioned. The vertical axis in FIG. 5 indicates normalized transmittance, and the horizontal axis indicates wavelength (unit: nm). As shown in FIG. 5, the spectral characteristics of the optical filter 213 ′ have transmission peaks near 420 nm and 550 nm, and have a certain transmittance or more between the transmission peaks. Similar to the optical filter 213 shown in FIG. 3, the transmittance between the transmission peaks of the optical filter 213 'is higher than 0 and lower than the half value of each transmission peak, more preferably 5% of each transmission peak value. From 10%. Here, in the optical filter 213 of FIG. 3, it is possible to obtain an image of natural color by having transmission peaks in three wavelength regions, while in the optical filter 213 ′ of FIG. By having a transmission peak in the region, an image with higher contrast can be obtained.

1 electronic endoscope system 100 electronic scope 200 processor 213 optical filter 220 signal processing circuit

Claims (4)

A light source emitting light including a visible light region;
An optical filter having a transmission peak at each of a plurality of specific wavelengths in a continuous wavelength range including a visible light range,
A color solid-state imaging device that receives reflected light from a subject illuminated by illumination light that has passed through the optical filter;
An image generation unit that processes an imaging signal output from the solid-state imaging device to generate a color image that can be displayed on a monitor;
Have
The plurality of specific wavelengths having the transmission peak is
Around 420 nm and around 550 nm ,
The specific wavelength range including the specific wavelength around 420 nm is a wavelength range having a transmission peak of a predetermined width centered on around 420 nm,
The specific wavelength range including the specific wavelength around 550 nm is a wavelength range having a transmission peak of a predetermined width centered on around 550 nm,
The optical filter is
In the wavelength region between each said specific wavelength range, has a high and low transmittance than half of the transmission peak than 0,
Among the specific wavelength bands centered around 420 nm, the shortest wavelength is located near 395 nm, and the wavelength band shorter than the shortest wavelength has a transmittance of 0 over the entire area,
The longest wavelength in the specific wavelength range centered on around 550 nm is located around 570 nm, and the wavelength range on the longer wavelength side than the longest wavelength has a transmittance of 0 over the entire area ,
Electronic endoscope system. The optical filter is
In the wavelength range between each specific wavelength range , it has a constant transmittance, which falls within the range of 5% to 10% of the transmission peak,
The electronic endoscope system according to claim 1. Optical filter switching means for inserting or retracting the optical filter with respect to the irradiation light path of the light source;
Operation means for receiving an input operation by the user;
And have
The optical filter switching means is
Inserting the optical filter into the irradiation light path or retracting the irradiation light path according to the input operation received by the operation means;
The electronic endoscope system according to claim 1 or 2. A light source emitting light including a visible light region;
An optical filter having a transmission peak at each of a plurality of specific wavelengths in a continuous wavelength range including a visible light range,
Have
The plurality of specific wavelengths having the transmission peak is
Around 420 nm and around 550 nm ,
The specific wavelength range including the specific wavelength around 420 nm is a wavelength range having a transmission peak of a predetermined width centered on around 420 nm,
The specific wavelength range including the specific wavelength around 550 nm is a wavelength range having a transmission peak of a predetermined width centered on around 550 nm,
The optical filter is
In the wavelength region between each said specific wavelength range, has a high and low transmittance than half of the transmission peak than 0,
Among the specific wavelength bands centered around 420 nm, the shortest wavelength is located near 395 nm, and the wavelength band shorter than the shortest wavelength has a transmittance of 0 over the entire area,
The longest wavelength in the specific wavelength range centered on around 550 nm is located around 570 nm, and the wavelength range on the longer wavelength side than the longest wavelength has a transmittance of 0 over the entire area ,
Light source device for endoscopes.