JP2017170169A - Scanning confocal endoscope system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an index unit capable of easily and stably acquiring an image for use in calibration without using a fluorescent paint in a scanning confocal endoscope system, and an image acquisition method.SOLUTION: The index unit for use in image evaluation of the scanning confocal endoscope system comprising a scanning confocal endoscope for applying excitation light to a subject and receiving fluorescent light excited by the excitation light, and a processor for generating an image on the basis of the fluorescent light that the scanning confocal endoscope receives, includes: an LED capable of emitting light with a wavelength equivalent to that of the fluorescent light; a collimating lens attached to a light-emitting plane of the LED; and a chart attached to the collimating lens and including an index for image evaluation formed thereon. The light from the LED passes through the collimating lens to be applied to the chart such that the index emits light, or a part of the chart, other than the index, emits light.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an index unit for a scanning confocal endoscope and an image acquisition method for acquiring a fluorescence image of a living tissue.

  2. Description of the Related Art Conventionally, there is known a scanning endoscope system that scans light guided by an optical fiber in a spiral shape with respect to an observation site and receives reflected light from the observation site to form an image (for example, a patent) Reference 1). In such a scanning endoscope system, a single mode type optical fiber is provided inside the endoscope, and a base end portion thereof is held in a cantilever shape by a biaxial actuator. The biaxial actuator two-dimensionally vibrates (resonates) the tip of the fiber in accordance with the natural frequency while modulating and amplifying the amplitude of vibration, and drives the tip of the optical fiber in a spiral shape. As a result, the illumination light guided from the light source by the optical fiber scans the observation region in a spiral shape, and an image of the irradiation region (scanning region) is acquired based on the return light from the observation region.

  In recent years, it has also been proposed to apply a scanning endoscope system as described in Patent Document 1 to a scanning confocal endoscope system (for example, Patent Document 2). The scanning confocal endoscope system irradiates a living tissue to which a drug (fluorescent agent) is administered with laser light (excitation light), and out of the fluorescence emitted from the living tissue, the focal position of the confocal optical system By extracting only components via pinholes arranged at conjugate positions, the living tissue can be observed at a higher magnification than an observation image obtained by a normal endoscope optical system. The scanning confocal endoscope system described in Patent Document 2 is an observation image obtained by a normal endoscope optical system by scanning a specific narrow region of a living tissue two-dimensionally or three-dimensionally with a laser beam. It is configured to be able to observe a minute object that cannot be observed at a magnification of 1, or to observe a tomographic part of a living tissue.

Special table 2008-514342 gazette JP 2011-255015 A

  In a scanning endoscope system as described in Patent Documents 1 and 2, reflected light or fluorescence from a scanning region (observation site) is received at a predetermined cycle timing (hereinafter referred to as “sampling point”). The luminance information at each sampling point is assigned to the monitor display coordinate system (the pixel position of the endoscopic image) to display a two-dimensional endoscopic image. Therefore, in order to generate a highly reproducible endoscope image without distortion, it is necessary to accurately match the scanning position of each sampling point with the display coordinate system of the monitor. Therefore, in this type of scanning endoscope system, calibration is performed so as to obtain an ideal scanning pattern while monitoring an actual scanning pattern (scanning trajectory). Specifically, in the system described in Patent Document 1, illumination light emitted from an optical fiber is received by a PSD (Position Sensitive Detector), and the position of an irradiation spot in a scanning pattern (scanning locus) is detected, Calibration is performed so as to obtain an ideal scanning pattern by adjusting the amplitude, phase, frequency, and the like of the voltage applied to the actuator.

  Also, as one of the calibrations, an image of an index such as a grid (lattice pattern) affixed to a rod-shaped brass member by a scanning endoscope system is acquired, and distortion of the acquired image is measured. It is also possible to perform image evaluation and distortion correction. Conventionally, in the scanning confocal endoscope system as described in Patent Document 2, when an image is evaluated, a fluorescent paint is applied to a grid used as an index, and the obtained fluorescent image is obtained. Based on the evaluation. However, since the fluorescent paint applied to the grid fades with time and the amount of laser light applied, it is necessary to repaint the fluorescent paint frequently, which is very complicated. In addition, when applying the fluorescent paint, unevenness in density may occur. In such a case, image distortion caused by the system cannot be properly determined. Furthermore, due to the fading of the fluorescent paint and unevenness of shading, there is a problem that the acquired image is not reproducible and it is difficult to perform stable evaluation.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to easily and stably use calibration in a scanning confocal endoscope system without using a fluorescent paint. An object of the present invention is to provide an index unit and an image acquisition method capable of acquiring an image.

  To achieve the above object, according to the present invention, a scanning confocal endoscope that irradiates a subject with excitation light and receives fluorescence excited by the excitation light, and the scanning confocal endoscope receives light. An index unit used for image evaluation of a scanning confocal endoscope system is provided. The index unit of the present invention includes an LED capable of emitting light having a wavelength corresponding to fluorescence, a collimating lens attached to the light emitting surface of the LED, and attached to the collimating lens to form an index for image evaluation. When the light from the LED irradiates the chart through the collimating lens, the indicator emits light, or a portion other than the indicator of the chart emits light.

  Thus, it is not necessary to apply a fluorescent paint to the index by causing the index to emit light with light having a wavelength corresponding to the fluorescence from the LED. For this reason, the trouble of repainting due to fading of the fluorescent paint and the distortion of the image due to unevenness in density are eliminated, and an image for image evaluation in calibration can be obtained easily and stably.

  The indicator unit may further include a housing that houses the LED, the collimating lens, and the chart, and the housing may have a cap shape that can be attached to the scanning confocal endoscope. With this configuration, it is possible to easily perform calibration as compared with a conventional large-scale calibration apparatus, and to easily position the index and the scanning confocal endoscope. It becomes possible.

  Further, the collimating lens and the chart may be subjected to antireflection processing. Furthermore, the chart may be made of glass or quartz. With this configuration, light from the LED can be efficiently incident on the scanning confocal endoscope.

  Further, the LED may be capable of changing the wavelength of the emitted light. With this configuration, in the scanning confocal endoscope system, an image of light having an arbitrary wavelength can be acquired and evaluated.

  Further, according to the present invention, a scanning confocal endoscope that irradiates a subject with excitation light and receives fluorescence excited by the excitation light, and an image based on fluorescence received by the scanning confocal endoscope. An image acquisition method used for image evaluation of a scanning confocal endoscope system comprising a processor for generating light having a wavelength corresponding to fluorescence from an LED, and an index for image evaluation A step of irradiating the formed chart; a step of receiving light emission of an indicator by irradiation or light emission of a portion other than the indicator of the chart by a scanning confocal endoscope; and Generating an image of the indicator based on the received light emission, and providing an image acquisition method.

  The image acquisition method of the present invention may further include a step of stopping the irradiation of excitation light in the scanning confocal endoscope. With this configuration, it is possible to reduce noise in the index image.

  Furthermore, the image acquisition method of the present invention may further include a step of detecting the focal position of the scanning confocal endoscope based on the amount of received light in the processor. With this configuration, it is possible to simplify the positioning of the scanning confocal endoscope.

  By using the index unit and the image acquisition method of the present invention, it is possible to acquire an image for calibration without using a fluorescent paint. Therefore, a reproducible and stable image is not required. Evaluation can be performed.

1 is a block diagram illustrating a schematic configuration of a scanning confocal endoscope system according to an embodiment of the present invention. It is a sectional side view which shows schematic structure of the confocal optical unit which concerns on embodiment of this invention. It is a figure which shows the rotation locus | trajectory of the front-end | tip of an optical fiber on an XY approximate surface. It is an external view of the parameter | index unit which concerns on embodiment of this invention. It is a figure which shows the pattern of the chart which concerns on embodiment of this invention. It is a flowchart which shows the flow of the image acquisition method which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a scanning confocal endoscope system 1 according to an embodiment of the present invention. The scanning confocal endoscope system 1 according to the present embodiment is a system designed by applying the principle of a confocal microscope, and is preferably configured to observe a subject with high magnification and high resolution. As shown in FIG. 1, the scanning confocal endoscope system 1 includes a system main body 100, a confocal probe 200, and a monitor 300. The confocal observation using the scanning confocal endoscope system 1 is performed in a state where the distal end surface of the flexible tubular confocal probe 200 is applied to the subject.

  The system main body 100 includes a light source 102, an optical demultiplexer / multiplexer (photocoupler) 104, a damper 106, a CPU 108, a CPU memory 110, an optical fiber 112, a filter 113, a light receiver 114, a video signal processing circuit 116, an image memory 118, And a video signal output circuit 120. The confocal probe 200 includes an optical fiber 202, a confocal optical unit 204, a sub CPU 206, a sub memory 208, and a scanning driver 210.

  First, normal observation by the scanning confocal endoscope system 1 will be described below. The light source 102 emits excitation light (wavelength: 488 nm) that excites the drug administered into the body cavity of the patient in accordance with the drive control of the CPU 108. The excitation light enters the optical demultiplexer / multiplexer 104. An optical connector 152 is coupled to one of the ports of the optical demultiplexer / multiplexer 104. The unnecessary port of the optical demultiplexer-multiplexer 104 is coupled to a damper 106 that terminates the excitation light emitted from the light source 102 without reflection. The excitation light incident on the former port passes through the optical connector 152 and enters the optical system arranged in the confocal probe 200.

  One end (hereinafter referred to as “base end”) of the optical fiber 202 is coupled to the optical demultiplexer-multiplexer 104 through the optical connector 152. The other end of the optical fiber 202 (hereinafter referred to as “tip”) is housed in a confocal optical unit 204 incorporated in the tip of the confocal probe 200. The excitation light emitted from the optical demultiplexer / multiplexer 104 passes through the optical connector 152, enters the proximal end of the optical fiber 202, transmits the optical fiber 202, and is emitted from the distal end of the optical fiber 202.

  FIG. 2A is a diagram schematically showing the configuration of the confocal optical unit 204. Hereinafter, for convenience of describing the confocal optical unit 204, the longitudinal direction of the confocal optical unit 204 is defined as the Z direction, and two directions orthogonal to the Z direction and orthogonal to each other are defined as the X direction and the Y direction. As shown in FIG. 2A, the confocal optical unit 204 has a metal outer cylinder 204A that houses various components. The outer cylinder 204A holds an inner cylinder 204B having an outer wall surface shape corresponding to the inner wall surface shape of the outer cylinder 204A so as to be slidable coaxially (Z direction). The optical fiber 202 is housed and supported in the inner cylinder 204B through openings formed in the base end surfaces of the outer cylinder 204A and the inner cylinder 204B, and the distal end of the optical fiber 202 (hereinafter referred to as “202a”) is provided. It functions as a secondary point light source of the scanning confocal endoscope system 1. The position of the tip 202a, which is a point light source, periodically changes based on control by the CPU. In FIG. 2A, the central axis AX indicates the axis of the optical fiber 202 arranged in the Z direction, and when the tip 202a of the optical fiber 202 is not oscillating (initial state), The central axis AX coincides with the optical path of the optical fiber 202.

  Returning to FIG. 1, the sub-memory 208 stores probe information such as identification information and various properties of the confocal probe 200. The sub CPU 206 reads probe information from the sub memory 208 when the system is activated, and transmits the probe information to the CPU 108 via the electrical connector 154 that electrically connects the system main body 100 and the confocal probe 200. The CPU 108 stores the transmitted probe information in the CPU memory 110. The CPU 108 reads the stored probe information when necessary, generates a signal necessary for controlling the confocal probe 200, and transmits the signal to the sub CPU 206. The sub CPU 206 designates a setting value necessary for the scan driver 210 in accordance with the control signal transmitted from the CPU 108.

  The scanning driver 210 generates a drive signal corresponding to the designated set value, and drives and controls the biaxial actuator 204C that is bonded and fixed to the outer peripheral surface of the optical fiber 202 near the tip 202a. FIG. 2B is a diagram schematically showing the configuration of the biaxial actuator 204C. As shown in FIG. 2B, the biaxial actuator 204C includes a pair of X-axis electrodes (“X” and “X ′” in the figure) and Y-axis electrodes (in the figure) connected to the scanning driver 210. "Y", "Y '") is a piezoelectric actuator formed on a piezoelectric body.

  The scan driver 210 applies an AC voltage X having a predetermined frequency between the X-axis electrodes of the biaxial actuator 204C to vibrate the piezoelectric body in the X direction, and has the same frequency as the AC voltage X and a phase. Is applied between the Y-axis electrodes to vibrate the piezoelectric body in the Y direction. The AC voltages X and Y are respectively defined as voltages that increase linearly in proportion to time and reach effective values (X) and (Y) over time (X) and (Y). The tip 202a of the optical fiber 202 is on a surface that approximates the XY plane (hereinafter referred to as "XY approximate surface") by combining the kinetic energy in the X and Y directions by the biaxial actuator 204C. Rotate to draw a spiral pattern around the central axis AX. The rotation trajectory of the tip 202a increases in proportion to the applied voltage, and draws a circular trajectory having the largest diameter when the AC voltage having the effective values (X) and (Y) is applied. FIG. 3 shows the rotation locus of the tip 202a on the XY approximate plane.

  The excitation light is emitted from the tip 202a of the optical fiber 202 during the period from the start of application of AC voltage to the biaxial actuator 204C to the stop of application. Hereinafter, for convenience of explanation, this period is referred to as a “sampling period”. As described above, when an AC voltage is applied to the biaxial actuator 204C, the tip 202a of the optical fiber 202 rotates so as to draw a spiral pattern around the central axis AX. For this reason, during the sampling period, the excitation light emitted from the tip 202a of the optical fiber 202 scans a predetermined circular scanning region around the central axis AX in a spiral shape. When the application of the AC voltage to the biaxial actuator 204C is stopped after the sampling period has elapsed, the vibration of the optical fiber 202 is attenuated. The circular motion of the tip 202a on the approximate XY plane converges as the vibration of the optical fiber 202 is attenuated, and the vibration of the optical fiber 202 becomes substantially zero after a predetermined time (that is, the tip 202a is on the central axis AX). Almost stop). Hereinafter, for convenience of explanation, a period from the end of the sampling period until the tip 202a substantially stops on the central axis AX is referred to as a “braking period”. After the braking period, the next sampling period is started after a predetermined time has elapsed. Hereinafter, for convenience of description, a period from the end of the braking period to the start of the next sampling period is referred to as a “settling period”. The settling period is a standby time for completely stopping the tip 202a of the optical fiber 202 on the central axis AX. By providing the settling time, the tip 202a can be scanned accurately. The period corresponding to one frame is composed of one sampling period and one braking period, and the frame rate can be adjusted by adjusting the settling period. That is, the settling period can be appropriately set from the relationship between the time until the tip 202a of the optical fiber 202 completely stops and the frame rate. In order to shorten the braking period, a braking torque may be positively applied by applying a reverse phase voltage to the biaxial actuator 204C in the initial stage of the braking period.

  An objective optical system 204D and a cover glass 204G are installed in front of the tip 202a of the optical fiber 202. The objective optical system 204D is composed of a plurality of optical lenses, and is held by the outer cylinder 204A via a lens frame (not shown). The lens frame is fixed and supported relative to the inner cylinder 204B inside the outer cylinder 204A. Therefore, the optical lens group held by the lens frame slides in the Z direction integrally with the inner cylinder 204B inside the outer cylinder 204A. The cover glass 204G is fixed so as to cover the tip of the outer cylinder 204A.

  A compression coil spring 204E and a shape memory alloy 204F are attached between the base end surface of the inner cylinder 204B and the inner wall surface of the outer cylinder 204A. The compression coil spring 204E is initially compressed and sandwiched in the Z direction from the natural length. The shape memory alloy 204F has a long bar shape in the Z direction, deforms when an external force is applied at room temperature, and has a property of restoring to a predetermined shape by a shape memory effect when heated to a certain temperature or higher. ing. The shape memory alloy 204F is designed such that the restoring force due to the shape memory effect is larger than the restoring force of the compression coil spring 204E. The scan driver 210 generates a drive signal corresponding to the set value designated by the sub CPU 206, and energizes and heats the shape memory alloy 204F to control the expansion / contraction amount. The shape memory alloy 204F advances and retracts the inner tube 204B in the Z direction together with the optical fiber 202 according to the amount of expansion and contraction.

  The excitation light emitted from the tip 202a of the optical fiber 202 passes through the objective optical system 204D and the cover glass 204G to form a spot on the surface or surface layer of the subject. The spot formation position is displaced in the Z-axis direction in accordance with the advance / retreat of the tip 202a, which is a point light source. That is, the confocal optical unit 204 scans the subject three-dimensionally by combining the periodic circular motion of the tip 202a on the XY approximate plane by the biaxial actuator 204C and the advance and retreat in the Z direction.

  Since the tip 202a of the optical fiber 202 is disposed at the front focal position of the objective optical system 204D, it functions as a confocal pinhole. Of the scattering component (fluorescence: peak wavelength 515 nm) of the subject excited by the excitation light, only fluorescence from a condensing point optically conjugate with the tip 202a is incident on the tip 202a. The fluorescence is transmitted through the optical fiber 202, passes through the optical connector 152, and enters the optical demultiplexer / multiplexer 104. The optical demultiplexer / multiplexer 104 separates the incident fluorescence from the excitation light emitted from the light source 102 and guides it to the optical fiber 112. The reflected light of the excitation light is also incident on the tip 202 a of the optical fiber 202 and guided to the optical fiber 112. Since the reflected light of the excitation light becomes noise when generating a fluorescent image, it is cut by the filter 113 provided in front of the light receiver 114, and only the fluorescence is detected by the light receiver 114. The light receiver 114 may be a high-sensitivity photodetector such as a photomultiplier tube in order to detect weak light with low noise.

  The detection signal is input to the video signal processing circuit 116. The video signal processing circuit 116 operates under the control of the CPU 108 to obtain a digital detection signal by sample-holding and AD converting the detection signal at a constant rate. Here, when the position (trajectory) of the tip 202a of the optical fiber 202 during the sampling period is determined, the spot forming position in the observation region (scanning region) corresponding to the position and the return light from the spot forming position are detected. Thus, the signal acquisition timing for obtaining the digital detection signal is almost uniquely determined. In the present embodiment, the spot formation position is estimated from the signal acquisition timing in advance with reference to the actual measurement result using a calibration jig or the like, and the position on the image corresponding to the estimated position is determined. The CPU memory 110 stores a remapping table that associates the determined signal acquisition timing with the pixel position (pixel address).

  The video signal processing circuit 116 refers to the remapping table and assigns the point image represented by each digital detection signal to the pixel address according to the signal acquisition timing. Hereinafter, for convenience of explanation, the above assignment work is referred to as remapping. The video signal processing circuit 116 buffers an image signal constituted by a spatial arrangement of each point image in the image memory 118 according to the remapping result in a frame unit. The buffered signal is swept from the image memory 118 to the video signal output circuit 120 at a predetermined timing, and the video signal conforms to a predetermined standard such as NTSC (National Television System Committee) or PAL (Phase alternating Line). To be output to the monitor 300. On the display screen of the monitor 300, a three-dimensional confocal fluorescent image of a subject with high magnification and high resolution is displayed.

  Next, calibration of the scanning confocal endoscope system 1 according to the present embodiment will be described. More specifically, an image acquisition method for evaluating an image acquired by the scanning confocal endoscope system 1 will be described. FIG. 4 is a side cross-sectional view showing a schematic configuration of an index unit 400 used for image acquisition for image evaluation of the present embodiment. As shown in FIG. 4, the index unit 400 includes an LED (Light Emitting Diode) 410, an LED drive board 415, a collimating lens 420, a chart 430, and a cylindrical cap-shaped housing 450 that houses these.

  The LED 410 is a surface-emitting green LED that emits uniform light over a predetermined area. In another embodiment, a configuration may be adopted in which surface emission is performed using a plurality of small LEDs. The LED 410 is mounted on the LED drive board 415 and emits green light (500 nm to 600 nm) corresponding to fluorescence according to the drive control of the LED drive board 415. The LED drive board 415 includes a constant current circuit for supplying a stable current to the LED 410, a power supply, and the like, and performs drive control of the LED 410 according to an operation of an operation button (not shown) provided on the index unit 400.

  The collimating lens 420 is attached to the light emitting surface of the LED 410 and converts the light emitted from the LED 410 into parallel light. The surface of the collimator lens 420 on the confocal probe 200 side (light emission side) is provided with an AR (Anti Reflection) coating so that the light from the LED 410 efficiently enters the confocal probe 200. Yes. Note that an AR coating is generally applied to the surface of the collimating lens 420 on the LED 410 side (light incident side) on the confocal probe 200 side.

  The chart 430 is an index used for image evaluation of the scanning confocal endoscope system 1, and is adhered and fixed to the collimating lens 420. Various patterns according to the purpose of image evaluation are formed on the surface of the chart 430 on the confocal probe 200 side (the surface opposite to the surface bonded to the collimating lens 420) by etching or the like. In the present embodiment, the light from the LED 410 is irradiated from the back surface of the chart 430 through the collimator lens 420, so that the patterning of the chart 430 emits light (negative) or other than the patterning emits light (positive). Thereby, the image of the pattern formed on the chart 430 is acquired by the confocal probe 200.

  FIG. 5 shows a pattern example of the chart 430. 5A shows a grid pattern, and FIG. 5B shows a vertical and horizontal line pattern. FIG. 5A and FIG. 5B are mainly used when image distortion is evaluated. FIG. 5C is a pattern for confirming the scanning region of the optical fiber 202, and FIG. 5D is a pattern for confirming the resolution. Since the optical fiber 202 of the confocal probe 200 of the present embodiment is scanned so as to draw a circular locus, the patterns shown in FIGS. 5C and 5D are circular. These four types of patterns may be formed on separate charts, but all of these four types of patterns may be formed on a single chart.

  The chart 430 is made of glass (blue plate) or quartz base in order to efficiently guide the light from the LED 410. Preferably, scratches can be prevented by creating the chart 430 with a chrome chart, and the chart 430 can be used for a long time without deterioration of the pattern. Further, an AR coating is applied to the adhesive surface of the chart 430 with the collimating lens 420 so as not to reflect light from the LED 410. Further, the thickness of the chart 430 is made as thin as possible in order to efficiently guide the light from the LED 410 to the confocal probe 200.

  The housing 450 is formed using a resin such as biocompatible poniferene ether (PPE) or polyphenylene sulfide (PPS). A mounting hole 455 having an inner diameter corresponding to the outer diameter of the outer cylinder 204 </ b> A of the confocal optical unit 204 is formed in the housing 450. By inserting the confocal probe 200 into the mounting hole 455, the confocal optical unit 200 can be easily positioned in the X direction and the Y direction with respect to the chart 430 (index). Further, when the index unit 400 is not mounted on the confocal probe 200, a shutter (not shown) may be provided at the entrance 455a of the mounting hole 455 in order to prevent light from the LED 410 from leaking from the housing 450. The shutter may be configured to open when the confocal probe 200 is pushed into the mounting hole 455 and to automatically close when the shutter is removed.

  Next, a flow of image acquisition for calibration in the present embodiment will be described with reference to FIG. First, the index unit 400 is attached to the tip of the confocal probe 200 (S1). Subsequently, the excitation light from the light source 102 is turned off under the control of the CPU 108 in accordance with an instruction to start calibration (S2). An instruction to start calibration is determined by automatically detecting operation of an operation button (not shown) by a user (operator, assistant, etc.) or that the index unit 400 is attached to the confocal probe 200. Is done.

  Subsequently, the LED 410 is driven by operating an operation button (not shown) of the index unit 400 (S3). As a result, light having a wavelength corresponding to fluorescence is emitted from the LED 410. Subsequently, the scanning driver 210 is controlled by the sub CPU 206 of the confocal probe 200 so that the inner tube 204B of the confocal optical unit 204 is advanced and retracted in the Z direction (S4). At this time, the CPU 108 monitors the amount of light received by the light receiver 114 and detects the Z position (focus position) at which the amount of received light is maximum. If a Z position where the amount of received light is maximized is found (S5: YES), the Z position is stored in the sub memory 208 of the confocal probe 200 (S6). Thus, the focal position can be easily detected by using the moving mechanism in the Z direction provided in the confocal probe 200. Therefore, when attaching the index unit 400 to the confocal probe 200, it is not necessary to strictly position the tip of the confocal probe with respect to the chart 430 in the Z direction.

  Thereafter, at the stored Z position, an image of the chart 430 is obtained by the same method as in the normal observation described above (S7). Here, since the excitation light from the light source 102 is turned off, an image (fluorescence image) of the chart 430 based on the light (fluorescence) emitted from the LED 410 is acquired. Based on the image acquired in this manner, the image distortion and resolution are evaluated.

  As described above, in this embodiment, since it is not necessary to apply a fluorescent paint to the index used for calibration, it is possible to easily acquire a stable image without being affected by the fading or shading unevenness of the fluorescent paint. And can be evaluated. Further, since the light quantity can be easily and stably controlled by current control by using the LED as an index, an image with the same light quantity can be obtained at any time, and evaluation with high reproducibility can be performed.

  Further, by using a cap-shaped member as an index for image evaluation, calibration can be easily performed without the need for a large-scale calibration device equipped with a conventional microstage. Furthermore, since patterning on the order of microns can be performed in the chart 430, it is possible to evaluate resolution and the like that were impossible with a conventional metal grid. Moreover, it becomes possible to evaluate light reception efficiency by using LED.

  The above is the description of the embodiments of the present invention. However, the present invention is not limited to the configurations in the above-described embodiments, and various combinations and modifications are possible within the scope of the technical idea of the present invention. . First, although the said embodiment demonstrated the case where it applied to the scanning confocal endoscope system which scans an observation object spirally, this invention is applied also to another scanning confocal endoscope system. It is possible. For example, the present invention can also be applied to a scanning endoscope system that employs a raster scan method that reciprocally scans the horizontal direction of the scan region, a Lissajous scan method that scans the scan region sinusoidally, and the like. . In this case, the pattern of the chart 430 corresponding to the shape of the trajectory by scanning is used. Moreover, although the confocal probe 200 of the present embodiment has been described as a probe type that is inserted into a patient's body (for example, in the digestive tract) via a forceps channel of an electronic endoscope, The electronic endoscope may be integrated with the electronic endoscope. In that case, the inner diameter of the mounting hole 455 of the index unit 400 is formed to correspond to the outer diameter of the electronic endoscope, and the chart 430 is appropriately fixed at a position where an image can be acquired by the confocal optical unit 204.

  The LED 410 is not limited to the green LED, and may be a white LED including at least light having a wavelength corresponding to fluorescence. Further, the LED 410 may be an LED capable of emitting light having a wavelength corresponding to at least fluorescence and capable of changing the wavelength. In this case, an image other than fluorescence (for example, an image by red light) can be acquired, and the range of evaluation can be expanded.

  In the above embodiment, the case where the index unit 400 is configured as an independent unit has been described as an example. However, the present invention is not limited to this, and the index unit 400 may be built in the system main body 100.

1 Scanning Confocal Endoscope System 100 System Main Body 102 Light Source 104 Optical Demultiplexer / Multiplexer 106 Damper 108 CPU
110 CPU memory 112 Optical fiber 114 Light receiver 116 Video signal processing circuit 118 Image memory 120 Video signal output circuit 122 Light source control circuit 200 Confocal probe 202 Optical fiber 204 Confocal optical unit 204C Biaxial actuator 206 Sub CPU
208 Sub memory 210 Scan driver 400 Indicator unit 410 LED
420 Collimating lens 430 chart

Claims (8)

A scanning confocal endoscope that irradiates a subject with excitation light and receives fluorescence excited by the excitation light; and a processor that generates an image based on the fluorescence received by the scanning confocal endoscope; An index unit used for image evaluation of a scanning confocal endoscope system comprising:
An LED capable of emitting light having a wavelength corresponding to the fluorescence;
A collimating lens attached to the light emitting surface of the LED;
A chart attached to the collimating lens and formed with an index for the image evaluation,
The indicator unit, wherein the indicator emits light when light from the LED irradiates the chart through the collimating lens, or a portion other than the indicator of the chart emits light. A housing for housing the LED, the collimating lens, and the chart;
The indicator unit according to claim 1, wherein the housing has a cap shape that can be attached to the scanning confocal endoscope.   The index unit according to claim 1, wherein the collimating lens and the chart are subjected to antireflection processing.   The indicator unit according to any one of claims 1 to 3, wherein the chart is made of glass or quartz.   The indicator unit according to any one of claims 1 to 4, wherein the LED is capable of changing a wavelength of light to be emitted. A scanning confocal endoscope that irradiates a subject with excitation light and receives fluorescence excited by the excitation light; and a processor that generates an image based on the fluorescence received by the scanning confocal endoscope; An image acquisition method used for image evaluation of a scanning confocal endoscope system comprising:
Emitting light of a wavelength corresponding to the fluorescence from the LED, and irradiating a chart on which the index for image evaluation is formed;
Receiving the light emission of the indicator by the irradiation or the light emission of a portion other than the indicator of the chart by the scanning confocal endoscope;
Generating an image of the index based on the light emission received by the scanning confocal endoscope by the processor.   The image acquisition method according to claim 6, further comprising stopping irradiation of the excitation light in the scanning confocal endoscope.   The image acquisition method according to claim 6, further comprising a step of detecting a focal position of the scanning confocal endoscope based on a received light amount in the processor.