JP2008125996A - Endoscope subject distance measurement system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure the distance from the distal end of an endoscope to the surface of a subject. <P>SOLUTION: The electronic endoscope comprises a first light guide and an imaging element. The outgoing end of the first light guide is disposed at the distal end of the electric endoscope, and the outgoing end of the first light guide is supported by an outgoing angle adjusting mechanism. The outgoing angle adjusting mechanism adjusts the direction of the outgoing end of the first light guide. The light beam is emitted from the first light guide only. The imaging element generates image signals and stores the signals in a second memory. The light beam is applied to the center of an image based on the image signals stored in the second memory (S200-S204, S209). The angle of inclination of the first light guide is detected (S205), and the distance to the subject is computed based on the angle of inclination (S206). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an endoscope subject distance measurement system that measures a distance from a distal end portion of an endoscope to a subject.

  An endoscope is used for observing a place where light and the field of view do not reach, for example, the inside of a body or a mechanical structure. Furthermore, an endoscope apparatus may be used not only for observing a subject but also as a diagnostic apparatus for special applications such as a fluorescence endoscope apparatus by combining with a system according to a desired purpose (Patent Document) 1).

  According to such an endoscope, the subject is illuminated by the glass fiber provided inside the insertion tube. The optical image of the illuminated subject is picked up by the image sensor, or the optical image of the illuminated subject is transmitted through the glass fiber, so that the subject can be observed.

  An imaging element and a glass fiber for transmitting an optical image are covered with an imaging optical system for forming an optical image. Therefore, if the distance from the tip of the endoscope to the surface of the subject is known, it is possible to grasp the actual size of the observed image.

However, since the subject is observed as a two-dimensional image, it has been difficult to grasp the distance from the distal end of the endoscope to the surface of the subject.
JP 2005-319213 A

  Therefore, an object of the present invention is to provide an endoscope subject distance measurement system that measures the distance from the endoscope tip to the subject surface.

  The endoscope subject distance measuring system according to the present invention directs light incident on the first end portion provided along the insertion tube of the endoscope from the second end portion provided at the distal end of the insertion tube to one point. A first light guide that emits light, a first light source capable of supplying first light to the first end, and emission of light from the second end provided near the second end. A light guide drive mechanism that moves the second end so as to change the direction, and an image signal corresponding to the captured image is generated by imaging the subject irradiated with the light emitted from the second end. An imaging device that forms an optical image of a subject on the imaging device, a position detection unit that detects an irradiation position of light emitted from the second end based on the image signal, and an irradiation position The second end is moved by the light guide drive mechanism so that is superimposed on the optical axis of the imaging optical system. A control unit, an angle detection unit that detects an angle in the emission direction when the irradiation position is changed to overlap the optical axis of the imaging optical system, and a distance from the image sensor to the subject based on the changed angle And a distance calculation unit for calculating a subject distance.

  In addition, it is preferable to include a signal processing unit that superimposes a scale image that displays the length of the vicinity of the optical image on the optical axis on the captured image based on the subject distance and the optical characteristics of the imaging optical system.

  The light guide driving unit has a magnetic body provided at the second end and a magnetic coil provided around the first light guide, and the second end is adjusted by adjusting a current flowing through the magnetic coil. It is preferable to move.

  The magnetic coil is preferably provided in the first and second radial directions of the first light guide.

  According to the present invention, it is possible to measure the distance from the distal end portion of the endoscope to the subject surface. Therefore, since the operator can grasp the actual size of the subject image, it is possible to contribute to more accurate diagnosis.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an external view of an endoscope unit having an endoscope point light irradiation position adjustment system to which an embodiment of the present invention is applied.

  The endoscope unit 10 includes an endoscope processor 20, an electronic endoscope 50, and a monitor 11. The endoscope processor 20 is connected to the electronic endoscope 50 and the monitor 11.

  The endoscope processor 20 is provided with a light source unit (not shown in FIG. 1) and a signal processing unit (not shown in FIG. 1). Light emitted from the light source unit is irradiated near the distal end of the insertion tube 51 of the electronic endoscope 50.

  An optical image of a subject irradiated with light is taken by the electronic endoscope 50. An image signal generated by photographing with the electronic endoscope 50 is sent to the signal processing unit.

  In the signal processing unit, predetermined signal processing is performed on the image signal sent from the electronic endoscope 50. The image signal subjected to the predetermined signal processing is sent to the monitor 11, and an image corresponding to the sent image signal is displayed on the monitor 11.

  Next, the configuration of the light source unit will be described with reference to FIG. The light source unit 30 includes a white light source 31, first and second laser light sources LD 1 and LD 2, a first mirror 32, a beam splitter 37, a fiber bundle 38, a condensing lens 39, a rotary shutter 33, first, second, A third motor M1, M2, M3, a rotary shutter control circuit 34, a beam splitter control circuit 35, and a light source drive circuit 36 are included.

  White light for illuminating the subject is emitted from the white light source 31. In a state where the endoscope processor 20 and the electronic endoscope 50 are connected (see FIG. 3), the incident end 52bi of the second light guide 52b provided in the electronic endoscope 50 and the white light source 31 are optically connected. Connected to. Further, in a state where the endoscope processor 20 and the electronic endoscope 50 are connected, the incident end 52ai of the first light guide 52a provided in the electronic endoscope 50 and the first and second laser light sources LD1, LD2 are connected. Are connected via the first mirror 32.

  A rotary shutter 33 is provided between the white light source 31 and the incident end 52bi of the second light guide 52b. As shown in FIG. 4, the rotary shutter 33 is provided with a light shielding portion 33s and an opening 33o along the circumferential direction of the disk. When the rotary shutter 33 is driven by the first motor M1, it is possible to switch between white light blocking and passage.

  Further, the rotary shutter 33 can be retracted from the optical path of white light by the rail R and the third motor M3 during normal photographing of a white color image (imaging in the odd and even field periods described later).

  Further, the beam splitter 37 is driven by the second motor M2, whereby the beam splitter 37 is inserted into the white light path (see FIG. 5) or retracted (see FIG. 2).

  As shown in FIG. 6, the beam splitter 37 has a characteristic of removing the short wavelength component of the incident light, and the short wavelength component of the white light emitted from the white light source 31 is removed. Therefore, by inserting the beam splitter 37, all components of white light are incident on the incident end 52bi. On the other hand, by removing the beam splitter 37, white light from which the short wavelength component is removed can be incident on the incident end 52bi. The beam splitter 37 has a characteristic of reflecting the excitation light emitted from the first laser light source LD1.

  The first motor M1 is connected to the rotary shutter control circuit 34. The driving of the rotary shutter 33 by the first motor M1 is controlled by the rotary shutter control circuit 34. The second motor M2 is connected to the beam splitter control circuit 35. The driving of the beam splitter 37 by the second motor M2 is controlled by the beam splitter control circuit 35.

  The first laser light source LD1 emits excitation light, for example, ultraviolet light, which causes the living tissue to emit autofluorescence. Red light is emitted from the second laser light source LD2. A fiber bundle 38 and a condenser lens 39 are provided between the first and second laser light sources LD 1 and LD 2 and the first mirror 32.

  The emission ends of the first and second laser light sources LD 1 and LD 2 are optically connected to the fiber bundle 38. The fibers on the emission end side of the fiber bundle 38 are bundled together. Light exiting from the exit end of the fiber bundle 38 is collected by the condenser lens 39. The condensed light is incident on the first mirror 32.

  When the beam splitter 37 is inserted into the white light optical path, the beam splitter 37 also overlaps the optical path of the excitation light emitted from the first laser light source LD1. When the beam splitter 37 is inserted into the optical path of the first laser beam LD1, the excitation light is reflected by the beam splitter 37 and enters the incident end 52bi of the second light guide 52b. The direction of 37 is determined (see FIG. 5). When the beam splitter 37 is retracted from the optical path of white light, the excitation light or red light is reflected by the first mirror 32 and enters the incident end 52ai of the first light guide 52ai (see FIG. 2).

  The first and second laser light sources LD 1 and LD 2 are connected to the light source driving circuit 36. Light emission and light emission stop of the first and second laser light sources LD1 and LD2 are controlled by a light source driving circuit 36.

  The operations of the rotary shutter control circuit 34, the beam splitter control circuit 35, and the light source drive circuit 36 are controlled by the system controller 21. The timing of each operation executed by the rotary shutter control circuit 34 and the light source driving circuit 36 is controlled by the timing controller 22.

  The entire operation of the endoscope unit 10 is controlled by the system controller 21. For example, the later-described CCD driver 23, coil driver 28, and signal processing unit 40 are controlled by the system controller 21.

  In addition, the timing controller 22 controls the timing of the operation performed by each part in the endoscope unit 10. For example, the timing controller 22 controls the timing of each operation executed by the CCD driver 23 and the signal processing unit 40.

  Next, the configuration of the electronic endoscope 50 will be described with reference to FIGS. The electronic endoscope 50 includes an insertion tube 51, a main body 53, a connector 54, and the like (see FIG. 1). An insertion tube 51 is attached to the main body 53. Further, the main body 53 is connected to the connector 54 via a connecting cable 55.

  In addition, the electronic endoscope 50 includes first and second light guides 52a and 52b, an image sensor 56, an excitation light cut filter 57, an emission angle adjusting mechanism 60, a light distribution lens 58, and an objective as an imaging optical system. A lens 59, a cover Cv, and the like are provided (see FIG. 7).

  When the connector 54 is connected to the endoscope processor 20, the second light guide 52b is optically connected to the white light source 31, and the first light guide 52a is optically connected to the first and second laser light sources LD1 and LD2. The image sensor 56 is connected to the CCD driver 23 and the signal processing unit 40, and the emission angle adjusting mechanism 60 is connected to the coil driver 28.

  When the connector 54 is connected to the endoscope processor 20, a plurality of switches (not shown) provided in the endoscope processor 20 and the system controller 21 are connected. As will be described later, the endoscope system 10 can display on the monitor 11 a white light image when the subject is irradiated with white light and an autofluorescence image when the subject is irradiated with excitation light. Switching of the image to be displayed on the monitor 11 is executed by inputting a command to a switch provided in the endoscope processor 20.

  The second light guide 52 b extends from the connector 54 to the distal end portion of the insertion tube 51. As described above, the white light emitted from the white light source 31 or the excitation light emitted from the first laser light source LD1 is incident on the incident end 52bi of the second light guide 52b. The light incident on the incident end 52bi is transmitted to the emission end 52bo. Light emitted from the emission end 52bo of the second light guide 52b is irradiated near the tip of the insertion tube 51 by the light distribution lens 58.

  The first light guide 52 a extends from the connector 54 to the distal end portion of the insertion tube 51. The first light guide 52a is supported by the insertion tube 51 in a portion from the main body 53 from the emission end 52ao of the first light guide 52a. The emission end 52ao of the first light guide 52a is movable along the radial direction of the first light guide 52a.

  As described above, the excitation light or red light emitted from the first and second laser light sources LD1 and LD2 enters the incident end 52ai of the first light guide 52a via the fiber instant 38 and the condenser lens 39. Is done. The light incident on the incident end 52ai is transmitted to the emission end 52ao.

  The emission end 52ao of the first light guide 52a is installed so that the light transmitted to the emission end 52ao is emitted toward a point within the irradiation range of the light emitted from the second light guide 52b. The first light guide 52a is sealed inside the insertion tube 51 by the cover Cv.

  The emission angle adjusting mechanism 60 is provided in the vicinity of the emission end 52ao of the first light guide 52a. As shown in FIG. 8, the emission angle adjusting mechanism includes a magnetic cover 61 and first to fourth magnetic coils 62a, 62b, 62c, and 62d.

  The magnetic cover 61 is formed of a magnetic material such as iron. The magnetic cover 61 is wound around the first light guide 52a in the vicinity of the emission end 52ao. The first to fourth magnetic coils 62 a, 62 b, 62 c and 62 d are provided around the first light guide 52 a so as to face the magnetic cover 61.

  The first and third magnetic coils 62a and 62c are disposed so as to sandwich the first light guide 52a along the first radial direction D1 of the first light guide 52a. The second and fourth magnetic coils 62b and 62d are arranged so as to sandwich the first light guide 52a along the second radial direction D2 perpendicular to the first radial direction D1. The first to fourth magnetic coils 62a to 62d are arranged so that the first and second radial directions D1 and D2 are parallel to the vertical and horizontal directions of the image sensor 56.

  The first to fourth magnetic coils 62 a, 62 b, 62 c and 62 d are connected to the coil driver 28. A drive current is sent as a coil drive signal from the coil driver 28 to each of the first to fourth magnetic coils 62a, 62b, 62c, and 62d. The coil drive signal is also sent to the signal processing unit 40 via the system controller 21 for subject distance measurement described later.

  By applying a drive current to the first and third magnetic coils 62a and 62c, an electromagnetic force along the first radial direction D1 is applied to the magnetic cover 61. Due to the electromagnetic force along the first radial direction D1, the emission end 52ao of the first light guide 52a is inclined along the first radial direction D1. As shown in FIGS. 9 and 10, the inclination angle along the first radial direction D1 can be adjusted by adjusting the current value of the drive current.

  Similarly, an electromagnetic force along the second radial direction D2 is applied to the magnetic cover 61 by causing a drive current to flow through the second and fourth magnetic coils 62b and 62d. Due to the electromagnetic force along the second radial direction D2, the emission end 52ao of the first light guide 52a is inclined along the second radial direction D2. By adjusting the current value of the drive current, the tilt angle along the second radial direction D2 can be adjusted.

  The electronic endoscope 50 is provided with an inclination angle adjustment lever (not shown) for inputting an adjustment amount of the inclination angle of the first light guide 52a. The adjustment amount of the tilt angle adjustment lever is sent to the system controller 21 as a signal. Based on the adjustment amount, the system controller 21 controls the coil driver 28 to transmit a coil drive signal corresponding to the adjustment amount to the first to fourth magnetic coils 62a, 62b, 62c, and 62d.

  In addition, the electronic endoscope 50 is provided with a rotation switch (not shown) for executing the rotational movement of the emission end 52ao of the first light guide 52a. When the user turns on the rotation switch, a rotation start command is sent to the system controller 21 as a signal.

  When receiving the rotation start command, the system controller 21 causes the coil driver 28 to transmit to the first to fourth magnetic coils 62a, 62b, 62c, 62d a coil driving signal for causing the emitting end 52ao to perform a circular motion. For example, by transmitting a sinusoidal coil drive signal whose phase is delayed by ¼ period in the same cycle to the first to fourth magnetic coils 62a, 62b, 62c, and 62d, the emission end 52ao performs circular motion. .

  Further, the electronic endoscope 50 is provided with an automatic adjustment switch (not shown) for starting automatic adjustment of the inclination angle of the first light guide 52a. When the user turns on the automatic adjustment switch, an adjustment start command is sent to the system controller 21 as a signal. On the other hand, when the user turns off the automatic adjustment switch, an adjustment stop command is sent to the system controller 21 as a signal.

  When receiving the adjustment start command, the system controller 21 causes the first to fourth magnetic coils 62a, 62b, 62c, and 62d to transmit a coil drive signal for automatically adjusting the inclination angle of the first light guide 52a. The automatic adjustment of the inclination angle of the first light guide 52a will be described later.

  An optical image by reflected light of the subject when irradiated with white light or red light, and an optical image by fluorescent light and reflected light of the subject when irradiated with excitation light are applied to the light receiving surface of the image sensor 56 by the objective lens 59. Imaged. Note that the optical axis of the objective lens 59 and the center of the effective imaging area of the image sensor 56 are arranged so as to overlap, and the optical image of the subject overlapping the optical axis of the objective lens 59 is the effective imaging area of the image sensor 56. An image is formed at the center.

  Based on the drive signal transmitted by the CCD driver 23, the image sensor 56 is driven. By driving the image sensor 56, an optical image formed on the light receiving surface is captured. By executing the imaging operation, an image signal is generated by the imaging device 56. The image signal is sent to the signal processing unit 40.

  During excitation light irradiation, the excitation light component reflected by the subject is removed from the light incident through the objective lens 59 by the excitation light cut filter 57. By removing the excitation light component, only the fluorescence component emitted from the living tissue as the subject is imaged by the image sensor 56.

  The optical image by the reflected light of the subject when irradiated with white light or red light, and the optical image by the fluorescent and reflected light of the subject when irradiated with excitation light are the emission end of the first light guide 52a. It also enters 52ao. The incident light is transmitted to the incident end 52ai of the first light guide 52a.

  The half mirror 24 is disposed between the incident end 52ai of the first light guide 52a and the first mirror 32 (see FIG. 2). The light emitted from the incident end 52ai of the first light guide 52a is reflected by the half mirror 24. The light reflected by the half mirror 24 is further reflected by the second mirror 25 and enters a spectroscope 26 provided in the endoscope processor 20.

  An excitation light cut filter 27 is provided between the spectroscope 26 and the second mirror 25. The excitation light component is removed from the optical image of the subject by the excitation light cut filter 27. Only the light component from which the excitation light is removed enters the spectroscope 26.

  The spectroscope 26 measures the spectroscopic spectrum of light incident on the spectroscope 26. By measuring the spectrum, a spectrum signal is generated. The generated spectrum signal is sent to the signal processing unit 40.

  Next, the configuration of the signal processing unit 40 will be described with reference to FIG. FIG. 11 is a block diagram schematically showing the internal configuration of the signal processing unit 40. The signal processing unit 40 includes a front signal processing unit 41, a rear signal processing unit 43, a register 44, first, second, and third memories 45a, 45b, and 45c, a memory controller 46, a scan converter 47, a marker detection unit 48, The difference calculation unit 49, the subject distance calculation unit 42c, and the scale image creation unit 42ig are configured.

  An image signal sent from the image sensor 56 is input to the pre-stage signal processing unit 41. In the pre-stage signal processing unit 41, the image signal is converted from an analog signal to a digital signal. Further, predetermined signal processing such as interpolation processing and white balance is performed on the image signal converted into the digital signal.

  The image signal that has undergone predetermined signal processing is sent to and stored in the first memory 45a or the second memory 45b. Further, the spectral signal is sent to the register 44 and temporarily stored. The spectral signal stored in the register 44 is sent to and stored in the third memory 45c.

  As shown in FIG. 12, the spectrum signal is formed by a synchronization signal (see FL) and a signal (see D1, D2,...) Corresponding to the fluorescence intensity for each wavelength band. For example, D1 corresponds to the fluorescence intensity in the band of 400 nm to 410 nm, and D2 corresponds to the fluorescence intensity in the band of 410 nm to 420 nm.

  When the spectrum signal is stored in the third memory 45c, the spectrum signal is converted into a spectrum graph signal corresponding to the spectrum intensity image SI graphed as shown in FIG. 13 and stored.

  The memory controller 46 controls the timing of storing and outputting image signals in the first to third memories 45a, 45b, and 45c. The memory controller 46 performs the above-described timing control based on the control signal output from the timing controller 22.

  The scan converter 47 creates a display image to be displayed on the monitor 11 based on the image signal and the spectrum graph signal stored in the first to third memories 45a, 45b, and 45c. A display image signal corresponding to the display image is sent to the subsequent signal processing unit 43.

  The post-stage signal processing unit 43 subjects the display image signal to predetermined signal processing such as clamping and blanking processing, and further converts the digital signal into an analog signal. The display image signal converted into the analog signal is sent to the monitor 11. As described above, an image corresponding to the display image signal is displayed on the monitor 11.

  The functions and operations of the marker detection unit 48, the difference calculation unit 49, the subject distance calculation unit 42c, and the scale image creation unit 42ig will be described later.

  Next, operation modes set in the endoscope processor 20 and operations executed in each operation mode will be described.

  The endoscope unit 10 is provided with a reference light image mode, an autofluorescence image mode, and a spectrum display mode. Each mode can be switched by a user's operation. Depending on the set mode, the rotary shutter 33 switches between shielding and passing, insertion and withdrawal of the beam splitter 37, and light emission from the first and second laser light sources LD1 and LD2.

  When the reference light image mode is set, the rotary shutter 33 is driven and controlled to pass white light. The beam splitter 37 is retracted from the white light path WL, and white light is incident on the incident end 52bi of the second light guide 52b. Note that the excitation light and red light are not emitted from the first and second laser light sources LD1 and LD2 (see FIG. 14). Accordingly, in the reference light image mode, the white light WL is irradiated from the light distribution lens 58 to the entire subject obj (see FIG. 15).

  Further, the image signal generated by the image sensor 56 when set to the reference light image mode is stored in the first memory 45a as a reference light image signal (see FIG. 11). Furthermore, reading of the spectral signal stored in the register 44 into the third memory 45c is stopped.

  When the reference light image mode is set, the scan converter 47 reads the reference light image signal from the first memory 45a and sends it to the subsequent signal processing unit 43 as a display image signal. As described above, the display signal is subjected to predetermined signal processing by the subsequent signal processing unit 43. As shown in FIG. 16, the reference light image WI is displayed on the entire monitor 11.

  When the auto fluorescent image mode is set, the rotary shutter 33 is driven so as to shield the white light WL. The beam splitter 37 is inserted into the optical path of the white light WL. Further, the excitation light EL is emitted from the first laser light source LD1, and the excitation light EL is incident on the incident end 52bi of the second light guide 52b. Note that red light is not emitted from the second laser light source EL2 (see FIG. 17). Therefore, in the autofluorescence image mode, the excitation light EL is irradiated from the light distribution lens 58 to the entire subject obj (see FIG. 15).

  Further, the image signal generated by the image sensor 56 when set to the self-fluorescent image mode is stored in the second memory 45b as a fluorescent image signal. Furthermore, reading of the spectral signal stored in the register 44 into the third memory 45c is stopped.

  When the auto-fluorescent image mode is set, the scan converter 47 reads the fluorescent image signal from the second memory 45b and sends it to the subsequent signal processing unit 43 as a display image signal. As described above, the display signal is subjected to predetermined signal processing by the subsequent signal processing unit 43. As shown in FIG. 18, the autofluorescence image FI is displayed on the entire monitor 11.

  When the spectral spectrum display mode is set, the white light WL is blocked and passed by the rotary shutter 33 continuously. The beam splitter 37 is retracted from the optical path of the white light WL. Further, the emission and emission stop of the excitation light EL from the first laser light source LD1 and the emission stop and emission of the red light RL from the second laser light source LD2 are continuously switched. As shown in FIG. 19, the rotation control of the rotary shutter 33 and the switching of the laser light sources LD1 and LD2 are performed at the timing synchronized with the field signal for driving the image sensor 56.

  In the first, third, fifth,... Field periods t1, t3, t5,..., The rotary shutter 33 is driven so that the white light WL passes, and the driving of the first laser light source LD1 is stopped. Red light RL is emitted from the second laser light source LD2 (see FIG. 20). Therefore, in the first, third, fifth,... Field periods t1, t3, t5,..., White light WL is irradiated from the light distribution lens 58 to the entire subject obj, and from the cover Cv toward one point of the subject. Red light RL is irradiated (see FIG. 21).

  In the second, fourth, sixth,... Field periods t2, t4, t6,..., The rotary shutter 33 is driven so as to block the white light WL, and the excitation light EL is emitted from the first laser light source LD1. Light is emitted, and the driving of the second laser light source LD2 is stopped (see FIG. 22). Therefore, the excitation light EL is irradiated from the cover Cv toward one point of the subject in the second, fourth, sixth,... Field periods t2, t4, t6,.

  Further, the image signals IS1, IS3, IS5,... Generated by the image sensor 56 in the first, third, fifth,... Field periods t1, t3, t5,. And stored in the first memory 45a (see FIG. 19). On the other hand, the spectral signal SS1, SS3, SS5,... Generated by the spectroscope 26 in the first, third, fifth,... Field periods t1, t3, t5, ... is stored in the third memory 45c. Without being erased.

  Further, the image signals IS2, IS4, IS6,... Generated by the image sensor 56 in the second, fourth, sixth,... Field periods t2, t4, t6,. 45b.

  On the other hand, the spectral signal signals SS2, SS4, SS6,... Generated by the spectroscope 26 in the second, fourth, sixth,... Field periods t2, t4, t6,. Stored in the third memory 45c. The spectral spectrum signals SS2, SS4, SS6,... Are signals corresponding to the spectral spectrum of the fluorescence generated at one point irradiated with the excitation light.

  When the spectral spectrum display mode is set, the scan converter 47 reads the point display image signal and the spectrum graph signal from the first and third memories 45a and 45c, respectively.

  An image including two images of a point display image PI (see FIG. 24) and a spectral intensity image SI (see FIG. 13) corresponding to the point display image signal is created as a display image by the scan converter 47 (see FIG. 25). .

  A display image signal corresponding to the created display image is sent to the subsequent signal processing unit 43. As described above, the display signal is subjected to predetermined signal processing by the subsequent signal processing unit 43. Two images of the point display image PI and the spectral intensity image SI are displayed on the monitor 11 based on the display image signal subjected to the signal processing.

  As described above, the spectral intensity image SI at the time of displaying two images has the second, fourth, sixth,... Field periods t2, t4, t6,..., That is, only the excitation light EL is transmitted from the first light guide 52a. It is created based on the spectral signal generated when it is irradiated. Therefore, the spectral intensity image SI displays the spectral spectrum of the autofluorescent component at one point irradiated with the excitation light from the first light guide 52a.

  In the point display image PI, a red marker M is displayed at one point irradiated with the red light RL (see FIG. 24). Since the traces of the excitation light EL and the red light RL emitted from the emission end 52ai of the first light guide 52a are the same, the marker M in the point display image PI is displayed at the position where the spectral spectrum is measured.

  It should be noted that the irradiation position of the light emitted from the first light guide 52a can be moved by operating the tilt angle adjusting lever. Therefore, it is possible to move the position of the marker M and the position where the spectral spectrum is measured in the point display image PI without changing the direction of the distal end portion of the insertion tube 51.

  Further, when the rotation switch is turned on, the first to fourth magnetic coils 62a and 62b are arranged so that the emission end 52ao of the first light guide 52a performs a circular motion of at least one rotation during a single field period. , 62c, 62d are driven. Therefore, when the rotary switch is turned on, a red marking circle C is displayed on the circumference where the red light RL is irradiated in the point display image PI (see FIG. 26).

  When the rotary switch is turned on, the spectral intensity image SI displays the spectral spectrum of the fluorescence in the region on the circumference irradiated with the excitation light EL.

  When the automatic adjustment switch is turned on, the inclination angle of the first light guide 52a is adjusted so that the marker M or the marking circle C is moved to the center of the point display image PI.

  When the automatic adjustment switch is turned on, the image signals IS2, IS4, IS6,... Stored in the second memory 45b are sent to the marker detector 48 (see FIG. 11). In the second, fourth, sixth,... Field periods t2, t4, t6,..., Light is emitted only from the first light guide 52a, which corresponds to the image signals IS2, IS4, IS6,. In the image to be reproduced, the luminance value of one point irradiated with light is higher than the luminance value of other regions.

  Based on the image signals IS2, IS4, IS6,..., The coordinates of the point irradiated with light are detected by the marker detector 48. The marker detection unit 48 detects the coordinates of the point having the highest luminance as the coordinates of the point irradiated with light.

  It should be noted that the coordinates of the irradiated point are detected as two-dimensional coordinates having the origin at the lower left of the effective imaging region of the image sensor 56 and having the horizontal direction x and the vertical direction y as coordinate axes. The detected coordinates are sent to the difference calculation unit 49 as coordinate data.

  As described above, the circular marking circle C is displayed in the second, fourth, sixth,... Field periods t2, t4, t6,. The marker detection unit 48 detects the coordinates of the locus of the marking circle C, and further calculates the coordinates of the center of the marking circle C from the coordinates of the locus.

  The difference calculation unit 49 calculates the difference (Δx, Δy) between the coordinates of the point irradiated with light and the coordinates of the center of the point display image PI. The calculated difference is sent to the system controller 21 as difference data.

  Based on the sent difference data, the system controller 21 controls the coil driver 28 so as to transmit coil drive signals to the first to fourth magnetic coils 62a to 62d.

  For example, when the lateral difference Δx is positive, the second and fourth magnetic coils 62b are arranged such that the emission end 52ao of the first light guide 52a is inclined in the direction opposite to the second radial direction D2. , 62d, a coil drive signal is sent. When the lateral difference Δx is negative, the second and fourth magnetic coils 62b and 62d are arranged so that the emission end 52ao of the first light guide 52a is inclined in the second radial direction D2. A coil drive signal is sent.

  When the vertical difference Δy is positive, the first and third magnetic coils 62a are arranged such that the emission end 52ao of the first light guide 52a is inclined in the direction opposite to the first radial direction D1. 62c, a coil drive signal is sent. When the vertical difference Δy is negative, the first and third magnetic coils 62a and 62c are arranged so that the emission end 52ao of the first light guide 52a is inclined in the first radial direction D1. A coil drive signal is sent.

  The adjustment of the inclination angle of the emission end 52ao of the first light guide 52a is repeated until both the horizontal and vertical differences Δx and Δy become zero.

  As described above, a coil drive signal is input to the signal processing unit 40 via the system controller 21. Based on the coil drive signal when the horizontal and vertical differences Δx and Δy are both zero, the subject distance, which is the distance from the light receiving surface of the image sensor 56 to the subject on the optical axis of the objective lens 59, is calculated. Calculated by the unit 42c. A method for calculating the subject distance from the coil drive signal will be described below.

  As shown in FIG. 27, the current value of the coil drive signal correlates with the inclination angle of the emission end 52ao of the first light guide 52a. Therefore, the inclination angle of the emission end 52ao is obtained from the current value of the coil drive signal.

  As shown in FIG. 28, the relationship of tan θ = D / L is established among the inclination angle θ of the exit end 52ao, the distance D from the exit end 52ao to the center of the image sensor 56, and the subject distance L. Since the distance between the non-inclined first light guide 52a and the center of the image sensor 56 is known, the distance D from the emission end 52ao to the center of the image sensor 56 is determined by the inclination angle θ.

  Therefore, the subject distance L is obtained by calculating D / (tan θ) from the distance D from the emission end 52ao to the center of the image sensor 56 and the inclination angle θ.

  The subject distance L is sent as data to the scale image creation unit 42ig. The scale image creating unit 42ig creates a scale image to be displayed over the point display image PI and a character image corresponding to the subject distance D.

  For example, a scale corresponding to a length of 5 mm is displayed in the displayed image. However, as described above, the imaging element 56 is covered with the objective lens 59, and the length of 5 mm in the image changes according to the focal length and the subject distance which are the optical characteristics of the objective lens. An image with a length scale is created.

  A ROM (not shown) is connected to the scale image creation unit 42ig. In the ROM, the length of the scale corresponding to the subject distance L is recorded as the number of pixels. The scale image creation unit 42ig reads the scale length corresponding to the subject distance L from the ROM, and creates a scale image.

  The created scale image and character image are sent to the subsequent signal processing unit 43 as data. In the post-stage signal processing unit 43, the scale image and the character image are superimposed on the point display image PI.

  After superimposing on the point display image PI, the post-stage signal processing unit 43 performs predetermined signal processing on the image signal of the display image including the point display image PI. Based on the display image signal subjected to the signal processing, two images of the point display image PI ′ displaying the subject distance Lc and the scale Sc and the spectral intensity image SI are displayed on the monitor 11 (see FIG. 29).

  Next, operations performed in the light source unit 30 and the signal processing unit 40 in the spectral display mode will be described with reference to the flowchart of FIG.

  By switching to the spectral spectrum display mode, processing for displaying a spectral intensity image in the present embodiment is started. First, in step S100, it is determined whether or not the white light WL is a period during which the white light WL is blocked by the shutter 33 or a period during which the white light WL is allowed to pass through.

  If it is a period during which the white light WL is blocked, the process proceeds to step S101. In step S101, the emission of the excitation light EL by the first laser light source LD1 is stopped, and the red light RL is emitted by the second laser light source LD2.

  After stopping the emission of the excitation light EL and emitting the red light RL, the process proceeds to step S102. In step S102, an imaging operation and a spectral spectrum are measured. By executing the imaging operation, a point display image signal is generated. By measuring the spectrum, a spectrum signal is generated.

  When the point display image signal and the spectral signal are generated, the process proceeds to step S103. In step S103, the point display image signal is stored in the first memory 45a. In addition, the spectrum signal is deleted.

  In step S100, if the white light WL is passing through the rotary shutter 33, the process proceeds to step S104. In step S104, the excitation light EL is emitted by the first laser light source LD1, and the emission of the red light RL by the second laser light source LD2 is stopped.

  After stopping the emission of the excitation light RL and the red light RL, the process proceeds to step S105. In step S105, the imaging operation and the measurement of the spectral spectrum are performed as in step S102. By executing the imaging operation, a fluorescence image signal when the excitation light EL is irradiated from the second light guide 52b is generated. By measuring the spectrum, a spectrum signal is generated.

  When the fluorescent image signal and the spectral signal are generated, the process proceeds to step S106. In step S106, the fluorescence image signal is stored in the second memory 45b. The spectral signal is stored in the third memory 45c.

  After storing the point display image signal in step S103 or after storing the spectral signal in step S106, the process proceeds to step S107. In step S107, the point display image signal and the spectral signal are read out to the scan converter 47.

  In the next step S108, a display image including two images of the point display image PI and the spectral intensity image SI is generated based on the point display image signal and the spectral spectrum signal. When two display images are generated, the process proceeds to step S109.

  In step S109, it is determined whether or not the operation mode is switched to a mode other than the spectral display mode. If not switched, the process returns to step S100, and the operations from step S100 to step S109 are repeated until switching is performed thereafter. If the operation mode is switched in step S109, the process for displaying the spectral intensity image SI is terminated.

  Next, processing for automatic adjustment of light irradiation position and subject distance measurement executed by the signal processing unit and the system controller 21 will be described with reference to the flowchart of FIG.

  This process is started when the automatic adjustment switch is turned on in the spectral spectrum display mode, and is executed in parallel with the operation performed in the above-described spectral spectrum display mode. Further, this processing ends when the spectral spectrum display mode is switched to another mode or when the automatic adjustment switch is switched OFF.

  In step S <b> 200, the fluorescence image signal stored in the second memory 45 b is output to the marker detection unit 48. In step S201, the position of the marker M is detected as coordinates based on the fluorescence image signal.

  After detecting the position of the marker M, differences Δx and Δy between the center coordinates of the point display image and the position coordinates of the marker M are calculated in step S202. In step S203, it is determined whether or not the differences Δx and Δy are both substantially zero.

  If at least one of the differences Δx and Δy is not zero, the process proceeds to step S204. In step S204, the emission end 52ao of the first light guide 52a is inclined in a direction in which Δx and / or Δy approaches zero. As described above, the amount of inclination is adjusted by adjusting the current value of the coil drive signal input to the first to fourth magnetic coils 62a, 62b, 62c, and 62d. After adjusting the tilt amount, the process proceeds to step S209.

  If the differences Δx and Δy are both substantially zero in step S203, the process proceeds to step S205. In step S205, the inclination angle θ of the emission end 52ao of the first light guide 52a is detected from the current value of the coil drive signal.

  After detecting the tilt angle θ, the process proceeds to step S206. In step S206, the subject distance L is calculated based on the inclination angle θ. In the next step S207, a scale image having a length corresponding to the subject distance L and a character image having the subject distance L are created.

  After creating the scale image and the character image, the process proceeds to step S208. In step S208, the scale image and the character image are superimposed on the point display image PI. When superimposing such as a scale image is completed, the process proceeds to step S209.

  In step S209, it is determined whether or not the fluorescence image signal has been updated. That is, it is determined whether or not the fluorescence image signal generated after the two-field period is stored in the second memory 45b.

  If the image signal has not been updated, it waits until it is updated. If the image signal has been updated, the process returns to step S200. Thereafter, the processing from step S200 to step S209 is repeated.

  As described above, according to the endoscope subject distance measurement system of this embodiment, it is possible to measure the subject distance L from the distal end of the endoscope to the subject surface.

  In the present embodiment, detection of the light irradiation position, adjustment of the tilt angle, and calculation of the subject distance L are performed based on an image taken when the excitation light EL is irradiated from the first light guide 52a. Although it is configured, it is possible to calculate the subject distance L in the same manner as in the present embodiment even if any light that can be detected by the image sensor 56 is incident.

  Therefore, the endoscope subject distance measurement system according to the present embodiment can be applied not only to the fluorescence endoscope system but also to other endoscope systems.

  In the present embodiment, the excitation light EL is incident on the first light guide 52a in order to perform spectroscopic measurement, but any other light may be incident. For example, the white light WL may be incident and spectroscopic measurement of the reflected light of the white light irradiated to the position of the marker M in the point display image PI may be performed.

  Further, in the present embodiment, the point display image PI is an image captured when the entire object obj is irradiated with the white light WL and the red light RL is irradiated at one point. It may be light. However, any light can be used as long as it can pass through the excitation light cut filter 57 provided in front of the image sensor 56 as the light irradiated to one point.

  For example, it may be an image taken when the excitation light EL is emitted from the second light guide 52b and the red light RL is simultaneously emitted from the first light guide 52a. According to such a point display image PI, it is also possible to display the spectral intensity image SI on the monitor 11 together with the autofluorescence image FI on which the marker M is displayed.

  In the present embodiment, the first mirror 32 and the beam splitter 37 are used to cause the excitation light EL to enter the incident ends 52ai and 52bi of the first and second light guides 52a and 52b, and the red light RL is supplied to the first light guide 52a and 52b. In this configuration, the red light RL is incident on the incident end 52ai of the first light guide 52a when the white light WL is incident on the incident end 52bi of the second light guide 52b. Any mechanism can be used as long as the excitation light EL is incident on the incident end 52ai of the first light guide 52a when the incidence of the white light WL on the incident end 52bi of the second light guide 52b is stopped. May be applied.

  In the present embodiment, the inclination angle of the emission end 52ao of the first light guide 52a is adjusted by the electromagnetic force generated by the first to fourth magnetic coils 62a to 62d and the magnetic cover 61. The tilt angle of the first light guide 52a may be adjusted by any other mechanism.

  In the present embodiment, the measured spectral spectrum is displayed as a graph, but the spectral spectrum may be displayed in other forms such as a table.

It is an external view of an endoscope unit having an endoscope point light irradiation position adjustment system to which an embodiment of the present invention is applied. It is a block diagram which shows roughly the internal structure of a light source unit. It is a block diagram which shows roughly the internal structure of an endoscope processor. It is a front view of a rotary shutter. It is a block diagram which shows the state which inserted the beam splitter on the optical path of white light in a light source unit. It is an optical characteristic figure of a beam splitter. It is a block diagram which shows roughly the internal structure of an electronic endoscope. It is a layout view showing the configuration of the emission angle adjustment mechanism. It is a 1st schematic diagram which shows the inclination state of the 1st light guide along a 1st radial direction. It is a 2nd schematic diagram which shows the inclination state of the 1st light guide along a 1st radial direction. It is a block diagram which shows roughly the internal structure of a signal processing unit. It is a conceptual diagram which shows the data structure of a spectrum signal. It is a schematic diagram of the spectral intensity image which graphed the spectral spectrum. It is a state figure for demonstrating the state of the light source unit at the time of reference light image mode. It is a state figure which shows the irradiation state of the light to a to-be-photographed object at the time of reference light image mode and autofluorescence image mode. It is a schematic diagram of a white light image. It is a state diagram for demonstrating the state of the light source unit at the time of autofluorescence image mode. It is a schematic diagram of an autofluorescence image. It is a timing chart for demonstrating the state of each site | part of the light source unit in a spectrum display mode, the storing to the 1st-3rd memory, and the preparation of a display image. It is a 1st state diagram for demonstrating the state of the light source unit at the time of spectral spectrum display mode. FIG. 21 is a state diagram showing a light irradiation state on a subject in the state of the light source unit of FIG. 20. It is a 2nd state figure for demonstrating the state of the light source unit at the time of spectral spectrum display mode. It is a state diagram which shows the irradiation state of the light to the to-be-photographed object in the state of the light source unit of FIG. It is a schematic diagram of a point display image. It is the model of the display image which displayed the point display image and the spectral intensity image simultaneously. It is a schematic diagram of a point display image when a marking circle is displayed. It is a graph which shows correlation with the electric current value of a coil drive signal, and the inclination | tilt angle of the output end of a 1st light guide. FIG. 6 is a state diagram of the distal end portion of the insertion tube when the emission end of the first light guide is inclined, and is a diagram for explaining the principle for obtaining the inclination angle and the subject distance. It is a schematic diagram of a display image that simultaneously displays a point display image on which a scale and subject distance are displayed and a spectral intensity image. It is a flowchart for demonstrating the operation | movement performed in a light source unit and a signal processing unit in the spectrum display mode. It is a flowchart for demonstrating the process performed by a signal processing unit and a system controller in the spectrum display mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Endoscope unit 20 Endoscope processor 28 Coil driver 40 Signal processing unit 42c Subject distance calculation part 42ig Scale image creation part 45a, 45b, 45c 1st, 2nd, 3rd memory 46 Memory controller 47 Scan converter 48 Marker Detection unit 49 Difference calculation unit 50 Electronic endoscope 51 Insertion tubes 52a and 52b First and second light guides 52ai and 52bi Incident ends 52ao and 52bo First and second light guides of the first and second light guides Of the light source 56 Image sensor 60 Output angle adjustment mechanism EL Excitation light FI Autofluorescence image LD1, LD2 First and second laser light sources obj Subject PI, PI 'Point display image

Claims (4)

A first light guide provided along the insertion tube of the endoscope and emitting light incident on the first end portion from the second end portion provided at the distal end of the insertion tube toward one point;
A first light source capable of supplying first light to the first end;
A light guide driving mechanism that is provided in the vicinity of the second end portion and moves the second end portion so as to change the emission direction of light from the second end portion;
An imaging element that generates an image signal corresponding to a captured image by imaging a subject irradiated with light emitted from the second end; and
An imaging optical system that forms an optical image of the subject on the image sensor;
A position detection unit that detects an irradiation position of light emitted from the second end based on the image signal;
A controller that causes the light guide drive mechanism to move the second end so that the irradiation position overlaps the optical axis of the imaging optical system;
An angle detector that detects a change angle of the emission direction when the irradiation position is changed so as to overlap the optical axis of the imaging optical system;
An endoscope subject distance measurement system comprising: a distance calculation unit that calculates a subject distance that is a distance from the image sensor to the subject based on the change angle.   A signal processing unit that superimposes a scale image that displays the length of the vicinity of the optical image on the optical axis on the captured image based on the subject distance and the optical characteristics of the imaging optical system. The endoscope subject distance measuring system according to Item 1.   The light guide driving unit includes a magnetic body provided at the second end portion and a magnetic coil provided around the first light guide, and the first current guide is adjusted by adjusting a current flowing through the magnetic coil. 3. The endoscope subject distance measuring system according to claim 1, wherein an end of the endoscope is moved.   4. The endoscope subject distance measuring system according to claim 3, wherein the magnetic coil is provided in first and second radial directions of the first light guide.

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