JP2009273687A - Endoscope apparatus capable of adjusting optical axis - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an image photographed with appropriate illumination by securely adjusting the optical axis. <P>SOLUTION: In adjusting the optical axis of an objective lens 13, a luminance contour line is created from a real-time image obtained by the illumination of an external light source, and the image is displayed in a monitor 55. The position of the objective lens 13 is adjusted along X' and Y' axes so that the position of the largest luminance of the luminance contour line matches the center of the screen and that the luminance contour line is a symmetrical distribution curve relative to the center of the screen. Meanwhile, in adjusting the optical axis of a condenser lens 26, a white chart is photographed, and the luminance contour line is displayed in the monitor 55 from the real-time image. The position of the objective lens 26 is adjusted in the direction of the X and Y axes and around the X and Y axes. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an endoscope apparatus capable of observing and treating a body organ and the like, and more particularly, to detecting color unevenness caused by a light source.

  In an endoscope apparatus, light emitted from a light source such as a xenon lamp enters a light guide via a condenser lens, and is irradiated toward a subject from a distal end portion of a scope. Reflected light from the subject is imaged by a photographing optical system provided at the distal end of the scope, and a subject image is formed on the image sensor. Then, a color image is generated based on the image signal read from the image sensor and displayed on the monitor.

  If the incident ends of the light source, the condensing lens, and the light guide are not accurately positioned, the amount of light incident on the light guide is reduced, and appropriate illumination light cannot be obtained. In order to use light from a light source without waste, a method of adjusting the optical axis position of a condensing lens is known (see Patent Documents 1 and 2).

In Patent Document 1, a motor for driving a condensing lens is arranged, light is incident on a photometric fiber or an infrared sensor facing each other, and a positional deviation of the optical axis is detected based on a difference in incident light amount. When the optical axis is deviated, the position of the condenser lens is changed by driving the motor so that the optical axes coincide. Moreover, in patent document 2, a condensing lens is made movable along an optical axis direction, and a condensing lens is moved to the position from which a maximum luminance value is obtained.
Japanese Patent Laid-Open No. 7-181399 JP 2000-249935 A

  In Patent Document 1, an optical axis shift is detected by a one-dimensional light amount distribution. For this reason, it cannot be detected whether the luminance distribution is evenly distributed around the optical axis or a position corresponding thereto. That is, it cannot be determined whether the two-dimensional luminance distribution on the plane is an appropriate distribution, and the optical axis adjustment is limited.

  The endoscope apparatus of the present invention is capable of displaying two-dimensional luminance contour lines, and passes through an illumination optical system that emits light from a light source from a scope tip and an imaging optical system. An image pickup means for generating a color image from an image signal obtained by light and a contour line display means for displaying a brightness contour line on the screen based on the image signal so that the brightness contour line is symmetric about a reference position on the screen. Further, at least one of the optical axes of the illumination optical system and the photographing optical system is adjusted.

  By displaying the brightness contour map on the screen, the two-dimensional brightness distribution becomes clear. For example, if a scope is prepared in which the center of the screen corresponds to the center of the optical axis and light is emitted from the center of the scope tip, the center of the screen is the center of the brightness contour line, that is, if there is no optical axis shift in the condenser lens, The luminance maximum position is displayed, and symmetrical luminance contour lines are displayed around the center of the screen. The operator can adjust the optical axis while viewing the distribution of luminance contour lines on the plane. As an optical axis adjustment method, the illumination optical system or the photographing optical system may be moved by a motor, or the assembly position may be adjusted by hand.

  An endoscope apparatus according to another aspect of the present invention is capable of automatically adjusting an optical axis, and includes an illuminating unit that emits light from a light source from a distal end of a scope via an illumination optical system, and an imaging optical system. Imaging means for generating a color image from an image signal obtained by passing light, contour line acquisition means for acquiring a luminance contour line based on the image signal, and illumination optics so that the luminance contour line is symmetric about a reference position And an optical axis adjusting means for adjusting an optical axis of at least one of the system and the photographing optical system.

  An endoscope apparatus according to another aspect of the present invention is capable of adjusting an optical axis in accordance with the irradiation characteristics of a scope, and illuminating means for emitting light from a light source from a distal end of the scope via an illumination optical system, Based on imaging contours for generating a color image from an image signal obtained by light passing through a photographing optical system, contour contour acquisition means for acquiring a luminance contour based on the image signal, and luminance contour data corresponding to a connected scope, And an optical axis adjusting means for adjusting at least one of the optical axes of the illumination optical system and the photographing optical system so that the luminance contour line is a target with respect to the reference position. In a situation where the luminance contour line data differs for each scope model depending on the optical system arrangement characteristics of the scope tip surface, the optical axis adjustment is performed by referring to the luminance contour line data corresponding to the connected scope. For example, a series of brightness contour data corresponding to the scope model may be stored in the memory, and the data of the connection scope may be selected, or the brightness contour data may be acquired from the connected scope.

  In order to detect a deviation along a direction perpendicular to the optical axis of the photographing optical system and the illumination optical system, it is desirable to determine whether or not the maximum luminance position of the luminance contour line is within an allowable area based on the reference position. For example, the screen center position is set as the reference position, and it is determined whether the maximum luminance position of the luminance contour line falls within the allowable area defined around the center of the screen or around the center.

  In the case of a scope that emits light away from the center of the scope tip, the maximum luminance position of the luminance contour line deviates from the center of the screen. Therefore, it is preferable that the optical axis adjusting means determine whether or not the maximum luminance position is within the allowable area determined according to the light emission characteristics of the distal end surface of the connected scope.

  On the other hand, in order to automatically determine whether or not the luminance contour line has symmetry, the optical axis adjustment means may determine based on the luminance dimming ratio of the portion around the luminance contour line with respect to the maximum luminance position. When the optical axis adjusting means has a luminance contour line that is not symmetrical with respect to the reference position, it is only necessary to adjust the inclination of at least one of the illumination optical system and the photographing optical system.

  The endoscope optical axis misalignment detection method of the present invention emits light from a light source from a scope distal end via an illumination optical system, and brightness contour lines based on an image signal obtained by the light passing through the photographing optical system And determining whether or not the luminance contour has symmetry about the reference position of the screen.

  According to the present invention, the optical axis can be adjusted with certainty, and a captured image can be obtained by appropriate illumination.

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

  FIG. 1 is a block diagram of an electronic endoscope apparatus according to this embodiment.

  The electronic endoscope apparatus includes a video scope 10 and a processor 20, and a keyboard 35, a monitor 40, and a computer 50 are connected to the processor 20. The video scope 10 is detachably connected to the processor 20.

  When the xenon lamp 24 is turned on, the light emitted from the lamp 24 enters the incident end 12A of the light guide 12 through a diaphragm (not shown) and the condenser lens 26. The light incident on the light guide 12 travels to the scope distal end side and exits from the scope distal end via the light distribution lens 11. Thereby, an observation part is irradiated with illumination light.

  The light reflected at the observation site passes through the objective lens 13 and reaches the light receiving surface of the CCD 14. As a result, a subject image is formed on the CCD 14 and an image signal corresponding to the subject image is generated. The image signal is read from the CCD 14 at regular time intervals and sent to the image signal processing circuit 22 of the processor 20 through the initial circuit 15.

  In the image signal processing circuit 22, various processes are performed on the image signal such as white balance adjustment and gamma correction to generate luminance Y and color difference signals Cb and Cr. The generated luminance and color difference signals Y, Cb, and Cr are output to the monitor 40 via the video signal processing circuit 23. As a result, a full color image is displayed on the monitor 40.

  A system control circuit 21 including a CPU, a ROM, and a RAM controls the operation of the processor 20 and outputs a control signal to a circuit such as an image signal processing circuit 22. A program relating to operation control is stored in the ROM of the system control circuit 21. The memory 29 stores data related to the scope and optical axis adjustment, and is read out as necessary.

  The computer 50 has a built-in grabber board that captures an image, captures a real-time image, and calculates a two-dimensional luminance distribution. Then, brightness contour lines based on the brightness information are displayed on the computer monitor 55.

  The position of the condenser lens 26 is controlled by a motor 27. Here, optical axis adjustment is performed so that the optical axis D of the condenser lens 26 coincides with the reference optical axis E. The optical axis E is defined by the lamp 24 and the incident end 12 </ b> A of the light guide 12. An axis adjustment control command is transmitted to the system control circuit 21 by operating the keyboard 35, and the system control circuit drives the motor 27 in accordance with the command.

  FIG. 2 is a schematic diagram of the condenser lens 26.

  The condenser lens 26 can be shifted along three axes (X axis, Y axis, Z axis) orthogonal to each other, and can be tilted around the X axis and the Y axis. The X axis and the Y axis are two axes defined on a plane perpendicular to the optical axis E and are orthogonal to each other. The Z axis is an axis along the optical axis.

  The motor 27 is configured by stepping motors 27A to 27E for movement in the X, Y, and Z axis directions and for position variation around the Z and Y axes. The condenser lens 26 is held by a holding member (not shown), and the motors 27A to 27E are connected to the holding member, respectively.

  The stepping motors 27 </ b> A to 27 </ b> E rotate by a predetermined number of rotations based on a control signal from the system control circuit 21. The condenser lens 26 moves along the X, Y, and Z axes or rotates around the X and Y axes by driving the stepping motors 27A to 27E. A conventionally well-known configuration may be applied to the holding mechanism of the condenser lens 26, and detailed description thereof is omitted here.

  The optical axis of the objective lens 13 can also be adjusted, and the assembly position of the objective lens 13 is adjusted at the time of manufacture so that the optical axis L of the objective lens 13 coincides with the reference optical axis M. The reference optical axis M is defined according to the position of the light receiving surface of the CCD 14. The position of the objective lens 13 ′ is adjusted with respect to the inclination about the X ′ axis, the Y ′ axis, the X ′ axis, and the Y ′ axis orthogonal to the optical axis M.

  FIG. 3 is a diagram showing luminance contour lines related to the objective lens 13 and the condenser lens 26. The optical axis adjustment of the objective lens 13 and the condenser lens 26 will be described with reference to FIG. The optical axes of the objective lens 13 and the condenser lens 26 are adjusted at the time of shipment or maintenance of the electronic endoscope apparatus.

  First, the optical axis adjustment of the objective lens 13 will be described. At the time of shipment of the electronic endoscope apparatus, an external light source such as an LED is disposed in front of the scope tip, and the external light source is turned on. An external light source such as an LED is a surface light source having a uniform luminance distribution, and is attached in close contact with the distal end portion of the scope so that light with higher luminance is incident toward the center portion of the distal end surface of the scope. After mounting the external light source, the computer 50 is made to capture a real-time image. At this time, the lamp 24 of the processor 20 is not turned on.

  In the computer 50, luminance distribution data is generated from the real-time image, and a luminance contour line SL is generated from the luminance distribution. The creation of the luminance contour line is performed by a conventionally known calculation method. The generated luminance contour line SL is displayed on the monitor 55. The xy coordinate system intersecting at the screen center corresponds to the XY coordinate system of the condenser lens 26 and the X′-Y ′ coordinate system of the objective lens 13, and the display area of the entire screen corresponds to the mask area of the CCD 14. To do. Here, contour lines are drawn for each luminance level 10.

  The operator determines whether or not the optical axis L of the objective lens 13 substantially matches the reference optical axis M while looking at the displayed luminance contour line SL. In FIG. 3, a luminance contour line having symmetry about the pixel position P of the maximum luminance value is drawn in the luminance contour line SL, and the luminance maximum position P is deviated from the screen center O of the monitor 55.

  When no optical axis deviation occurs, a symmetrical luminance contour line is displayed with the screen center O as the center. On the other hand, when the optical axis shift occurs along the X ′ and Y ′ axis directions, the maximum luminance position P does not coincide with the screen center O. In addition, when the optical axis shift occurs due to the inclination around the X axis and the Y axis, a deviation (elliptical curve) along the x direction or the y direction occurs with respect to the curve of the contour line luminance distribution, and the luminance is asymmetrical. The distribution is displayed.

  In the case of the luminance contour line SL in FIG. 3, the luminance maximum position P does not coincide with the screen center O, while the luminance contour line SL has a symmetrical distribution curve with the luminance maximum position P as the center. Therefore, it is determined that the optical axis L of the objective lens 13 is shifted in the X ′ and Y ′ axis directions with respect to the reference optical axis M of the light guide 12.

  When the optical axis deviation becomes clear, the operator changes the position of the objective lens 13 of the scope 10. That is, the position and inclination of the objective lens 13 are finely adjusted until a symmetrical luminance contour line is displayed with the screen center O as the maximum luminance position P. In the case of the luminance contour line SL in FIG. 3, the objective lens 13 is shifted along the X ′ and Y ′ axis directions.

  Next, the optical axis adjustment of the condenser lens 26 will be described. At the time of shipment or maintenance of the electronic endoscope apparatus, a chart that is a white subject is photographed, and a real-time image is taken into the computer 50. However, the optical axis adjustment of the condenser lens 26 is performed after the adjustment of the scope (objective lens). In the computer 50, a luminance distribution is calculated based on the luminance signal Y, and a luminance contour line ML is obtained (see FIG. 3).

  When no optical axis deviation occurs, the luminance contour line has symmetry with respect to the screen center O. From the luminance contour line ML shown in FIG. 3, it can be seen that the optical axis E of the condenser lens 26 is shifted from the optical axis D of the light guide 12. However, it is assumed that a video scope that emits light toward the subject from the vicinity of the center of the scope tip surface is connected.

  The operator operates the keyboard 35 to drive the stepping motors 27A to 27E to eliminate the optical axis deviation. The position and inclination of the condenser lens 26 are finely adjusted until a symmetrical brightness contour line is displayed with the screen center O as the brightness maximum position P. In the case of the luminance contour line ML of FIG. 3, the condenser lens 26 is shifted along the X and Y axis directions to eliminate the optical axis deviation. Further, in the optical axis adjustment of the condenser lens 26, the condenser lens 26 is shifted along the Z axis, that is, the direction of the optical axis E, and positioned at the point where the maximum luminance value at the luminance maximum position P is highest.

  As described above, according to the present embodiment, the computer 50 is connected to the processor 20 of the electronic endoscope apparatus, and optical axis adjustment is performed at the time of shipment or maintenance of the electronic endoscope apparatus. In the case of adjusting the optical axis of the objective lens 13, a brightness contour line SL is created from a real-time image obtained by illumination of an external light source and displayed on the monitor 55. Then, the position of the objective lens 13 is set to the X ′ and Y ′ axes so that the maximum luminance position P of the luminance contour line SL coincides with the screen center O and the luminance contour line SL becomes a distribution curve symmetrical to the screen center O. Adjust along.

  On the other hand, in the case of adjusting the optical axis of the condenser lens 26, a white chart is photographed and the brightness contour ML is displayed on the monitor 55 from the real-time image. Then, the position of the objective lens 13 is set in the X and Y axis directions so that the maximum luminance position P of the luminance contour line SL coincides with the screen center O and the luminance contour line ML is a symmetrical distribution curve with respect to the screen center O. Adjust around the X and Y axes. Further, the position of the condenser lens 26 is adjusted with respect to the Z axis so as to obtain the maximum luminance value.

  Since the luminance distribution is displayed in a two-dimensional distribution, it is clearly visible how much the optical axis is shifted. As a result, the optical axis can be adjusted accurately and quickly. Regarding the optical axis adjustment, the position of the CCD 14 may be relatively adjusted instead of the objective lens 13, and the incident end position of the light guide may be adjusted instead of the condenser lens 26.

  Next, the electronic endoscope apparatus according to the second embodiment will be described with reference to FIGS. In the second embodiment, the optical axis of the condenser lens is automatically adjusted. About another structure, it is the same as 1st Embodiment.

  FIG. 4 is a block diagram of an electronic endoscope apparatus according to the second embodiment.

  The computer 50 is connected to the system control circuit 21 of the processor 20 so that data can communicate with each other. When adjusting the optical axis of the condenser lens 26, the computer 50 takes in a real-time image and generates a luminance contour line. Then, it is determined whether or not an optical axis deviation has occurred, and a control signal is output to the system control circuit 21 for optical axis adjustment.

  The system control circuit 21 drives the motor 27 based on the control signal sent from the computer 50. The motor 27 moves the condenser lens 26 along the X, Y, and Z axes, or adjusts the inclination about the X and Y axes.

  FIG. 5 is a flowchart showing the optical axis adjustment processing of the condenser lens 26 executed by the computer 50 and the processor 20. Start by taking a chart of a white subject.

  In step S101, the luminance contour line TL is obtained based on the real-time image. In step S102, it is determined whether or not the maximum luminance position is the screen center O and the peripheral dimming ratio is substantially the same along the periphery of the luminance contour line.

FIG. 6 is a diagram showing luminance contour lines in the second embodiment. The maximum luminance position P is deviated from the screen center O by (x ₀ , y ₀ ). In step S102, the luminance value Pm at the maximum luminance position P is detected, and the luminance values Px1, Px2, Py1, and Py2 of the four peripheral pixels in the peripheral portion of the screen are detected.

  The luminance values Px1 and Px2 represent the luminance values at the intersections of the straight line L1 along the x direction passing through the maximum luminance position P and the edge of the screen (around the mask area), and the luminance values Py1 and Py2 indicate the maximum luminance position P. The luminance value at the intersection of the straight line L2 along the passing y direction and the screen edge is shown.

  In step S102, as the determination of the optical axis deviation, it is determined whether or not the maximum luminance position P (x0, y0) coincides with the screen center O or belongs to an allowable area defined around the screen center O. Is done. When the maximum luminance position P (x0, y0) is outside the allowable area, the condensing lens 26 is misaligned with respect to the X axis and the Y axis.

Further, in step S102, as the determination of the optical axis deviation, the values of the dimming ratios ML and MR and the dimming ratios MA and MB obtained by the following formulas match each other or the difference is within a predetermined allowable range. It is determined whether or not there is.

MR = (1-Prx1 / Prm) × 100 (1)
ML = (1-Prx2 / Prm) × 100 (2)
MA = (1-Pry1 / Prm) × 100 (3)
MB = (1-Pry2 / Prm) × 100 (4)

However, Prx1, Prx2, Pry1, and Pry2 are values determined by normalizing the luminance value Pm at the luminance maximum position P. For example, when the luminance value Pm is 168, Prm is normalized as 100, Px1, Prx1, Prx2, Pry1, and Pry2 are obtained by multiplying Px2, Py1, and Py2 by 100/168, respectively.

  As described above, when the converging lens 26 is tilted around the X axis and an optical axis shift occurs, the luminance contour lines are asymmetric in the x direction and become asymmetric. In this embodiment, when the dimming ratios ML and MR do not match or the difference does not fall within a predetermined allowable range, the luminance contour lines are biased in the x direction, that is, due to the inclination around the X axis. Therefore, it is determined that the optical axis is shifted.

  The optical axis deviation around the Y axis is similarly determined. That is, if the dimming ratios ML and MR do not match, or if the difference does not fall within a predetermined allowable range, it is determined that an optical axis shift has occurred around the Y axis.

  If the maximum luminance position P (x0, y0) coincides with the screen center O or belongs to the allowable area, it is determined that the luminance contour line TL is a distribution curve centered on the maximum luminance position P. Furthermore, when the values of the light ratios ML and MR and the dimming ratios MA and MB match each other or the difference falls within a predetermined allowable range, the luminance contour TL is around the maximum luminance position P (screen center O). It is determined that the distribution curve has symmetry. That is, it is determined that no optical axis deviation has occurred (S103).

  On the other hand, when the maximum luminance position P (x0, y0) is outside the allowable area, or the difference between the light ratios ML and MR or the dimming ratios MA and MB exceeds the allowable range, the light is applied to the condenser lens 26. It is determined that an axis deviation has occurred (S104). In step S105, an optical axis adjustment process regarding the X and Y axes is performed. The optical axis adjustment process is performed based on a control signal from the computer 50.

  In step S106, an optical axis adjustment process for the Z axis of the condenser lens 26 is performed. That is, the condenser lens 26 is moved stepwise by the stepping motor 27E, and the position of the condenser lens 26 at which the luminance value Pm at the maximum luminance position P becomes the largest is obtained.

  FIG. 7 is a subroutine of step S105 in FIG.

  In step S201, in the determination in step S102 of FIG. 5, whether the maximum luminance position P has shifted from the screen center O along the screen x direction, that is, whether the optical axis shift of the condenser lens 26 has occurred along the X axis. To be judged. If a positional deviation has occurred along the screen x direction, the process proceeds to step S205, and the condenser lens 26 is moved in the X axis direction so as to eliminate the optical axis deviation. Here, a position at which the optical axis deviation is eliminated is obtained by a conventionally known hill-climbing method.

  Similarly, in steps S202, S203, and S204, it is determined whether or not there has been a deviation in the screen y direction, a deviation in luminance contour line in the x direction, and a deviation in luminance contour line in the y direction. If the optical axis is deviated, the movement of the condenser lens 26 in the Y-axis direction, the inclination around the X axis, and the inclination around the Y axis are adjusted in steps S206, S207, and S208.

  As described above, according to the second embodiment, the optical axis is automatically adjusted. Regarding the optical axis adjustment, the optical axis adjustment may be performed without displaying the brightness contour distribution on the monitor 55. Further, the optical axis may be adjusted by the processor body. Further, the optical axis of the objective lens 13 may be automatically adjusted.

  Further, only the optical axis deviation may be automatically determined, and the optical axis adjustment may be adjusted by the operator as in the first embodiment.

  Next, an electronic endoscope apparatus according to a third embodiment will be described with reference to FIGS. In the third embodiment, the optical axis is adjusted according to the scope model. About another structure, it is the same as 2nd Embodiment.

  FIG. 8 is a flowchart showing optical axis adjustment processing in the third embodiment.

  When the video scope 10 is connected to the processor 20, scope model information is transmitted from the video scope 10 to the processor 20 and stored in the memory 29. In step S <b> 301, model information of the video scope 10 is transmitted from the processor 20 to the computer 50.

  In step S <b> 302, luminance contour data corresponding to the video scope 10 is transmitted from the processor 20 to the computer 50. Similar to the scope model information, luminance contour line data is stored in the memory 29 when the video scope 10 is connected to the processor 20.

  In step S303, a luminance contour line is generated from the real-time image, and based on the luminance contour line, a maximum luminance value Pm and a dimming ratio MR, ML, MA, MB at the maximum luminance position P are calculated. In step S304, it is determined whether the maximum luminance position P and the dimming ratios MR, ML, MA, and MB satisfy the design specifications.

  FIG. 9 is a front view of the distal end portion of the video scope. The position of the light distribution lens on the scope distal end surface 10S, that is, the position of the light guide exit end differs depending on the video scope model. In the type A video scope shown in FIG. 9, the light distribution lens 11 is arranged at an asymmetric position with respect to the objective lens 13 of the scope. In this case, when there is no optical axis deviation, the maximum luminance position P is not located at the screen center O. On the other hand, in the case of the type B video scope, the light distribution lens 11 is arranged at a symmetrical position with respect to the objective lens 13. Therefore, the maximum luminance position P coincides with the screen center O when no optical axis deviation occurs.

  In the memory 29 of the processor 20, the maximum luminance position and the dimming ratio based on the luminance contour distribution of the connected videoscope are stored as data. In step S304, it is determined whether or not the maximum luminance position P is within an allowable range K according to the connection scope. Then, it is determined whether the calculated dimming ratios MR, ML, MA, MB match the dimming ratio data, or whether the difference is within an allowable range.

  FIG. 10 is a diagram showing luminance contour lines in the third embodiment. The video scope used here emits light at a position deviating from the center of the scope tip surface. Therefore, as shown in FIG. 10, the allowable range K of the maximum luminance position P is deviated from the screen center O. In step S304, it is determined whether the detected maximum luminance position P and the dimming ratio are the dimming ratio and the maximum luminance position satisfying the design specifications. That is, it is determined whether or not the maximum luminance position P is located within the allowable range K corresponding to the light emission characteristics of the video scope used, and whether or not the luminance contour line TL has symmetry about the maximum luminance position P.

  If the maximum luminance position P is within the allowable range K and the calculated dimming ratios MR, ML, MA, MB match the dimming ratio data or the difference is within the allowable range, the optical axis shift (S305). On the other hand, if not, it is determined that an optical axis shift has occurred (S306), and an optical axis adjustment process is performed for the X and Y axes (S307). In step S308, an optical axis adjustment process related to the Z axis is performed.

  Also in the first and second embodiments, the design specification range may be set according to the luminance distribution characteristics of the scope distal end surface, as in the third embodiment.

It is a block diagram of the electronic endoscope apparatus which is this embodiment. It is the schematic of a condensing lens. It is the figure which showed the brightness | luminance contour line regarding an objective lens and a condensing lens. It is a block diagram of the electronic endoscope apparatus which is 2nd Embodiment. It is the flowchart which showed the optical axis adjustment process of the condensing lens performed with a computer and a processor. It is the figure which showed the brightness | luminance contour line in 2nd Embodiment. This is a subroutine of step S105 in FIG. It is the flowchart which showed the optical axis adjustment process in 3rd Embodiment. It is the figure which showed the front view of a videoscope front-end | tip part. It is the figure which showed the brightness | luminance contour line in 3rd Embodiment.

Explanation of symbols

10 Videoscope 12 Light guide 13 Objective lens (photographing optical system)
14 CCD
20 Processor 21 System control circuit 24 Lamp 26 Condensing lens 27 Motor 50 Computer SL, ML, TL, KL Luminance contour line P Luminance maximum position

Claims (8)

Illumination means for emitting light from the light source from the distal end of the scope via the illumination optical system;
Imaging means for generating a color image from an image signal obtained by light passing through a photographing optical system;
Contour line display means for displaying brightness contour lines on the screen based on the image signal,
An endoscope apparatus, wherein an optical axis of at least one of the illumination optical system and the photographing optical system is adjusted so that a luminance contour line is symmetric with respect to a reference position on a screen. Illumination means for emitting light from the light source from the distal end of the scope via the illumination optical system;
Imaging means for generating a color image from an image signal obtained by light passing through a photographing optical system;
Contour line acquisition means for acquiring a luminance contour line based on an image signal;
An endoscope comprising: an optical axis adjusting unit that adjusts at least one of the optical axes of the illumination optical system and the photographing optical system so that luminance contour lines are symmetrical about a reference position. apparatus. Illumination means for emitting light from the light source from the distal end of the scope via the illumination optical system;
Imaging means for generating a color image from an image signal obtained by light passing through a photographing optical system;
Contour line acquisition means for acquiring a luminance contour line based on an image signal;
Optical axis adjustment that adjusts the optical axis of at least one of the illumination optical system and the imaging optical system based on luminance contour data corresponding to the connected scope so that the luminance contour is symmetric about a reference position An endoscope apparatus comprising: means.   The endoscope apparatus according to any one of claims 2 to 3, wherein the optical axis adjustment unit determines whether or not a maximum luminance position of a luminance contour line is within an allowable area based on a reference position.   The endoscope apparatus according to claim 4, wherein the optical axis adjustment unit determines whether or not a maximum luminance position is within an allowable area determined according to a light emission characteristic of a distal end surface of a connected scope. .   The endoscope according to any one of claims 2 to 3, wherein the optical axis adjusting means determines the symmetry of the luminance contour line based on a luminance dimming ratio of a portion around the luminance contour line with respect to the maximum luminance position. apparatus.   4. The optical axis adjusting means adjusts an inclination of at least one of the illumination optical system and the photographing optical system when luminance contour lines are not symmetrical with respect to a reference position. The endoscope apparatus according to any one of the above. Light from the light source is emitted from the tip of the scope via the illumination optical system,
Based on the image signal obtained by the light passing through the photographic optical system,
A method for detecting an optical axis deviation for an endoscope, comprising determining whether or not a luminance contour has symmetry with respect to a reference position on a screen.

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