JP2011139734A - Endoscope apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endoscope apparatus capable of displaying distance between an object for observation and the distal end of an endoscope. <P>SOLUTION: An initial setting device mainly includes a fixing part 51 for fixing the distal end 21 of an endoscopic scope 20, a target 52, and a base 53 in which the fixing part 51 and the target 52 are mounted. When the distance from the distal end 21 to the target 52 is xi, a laser bright spot Li appears on the target 52. When the distance from the distal end 21 to the target 52 is xii, a laser bright spot Lii appears on the target 52. When the distance from the distal end 21 to the target 52 is xiii, a laser bright spot Liii appears on the target 52. The distance from the distal end of the distal end 21 to the target 52 is measured by using the distance from a center point P of the target 52 to the center of the bright spot in an image. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an endoscope apparatus that displays a distance between an observation object and an endoscope distal end portion.

  The endoscope apparatus includes an endoscope scope that is inserted into a subject's body and an endoscope processor that is provided outside the subject's body and performs image processing. A distal end portion of the endoscope scope is provided with a light guide that irradiates an observation target with illumination light, an imaging device, and an imaging lens. The imaging element images an observation object inside the body via the imaging lens, and transmits the obtained observation image to the endoscope processor. The endoscope processor displays the observation image on the display device after image processing.

  At this time, a configuration that irradiates the observation object with a plurality of spot lights, and measures the distance between the distal end of the endoscope scope and the observation object from the interval in the endoscope visual field of these spot lights, And the structure which measures the magnitude | size of an observation target object from the ratio of the observation target object in an endoscope visual field is known (patent document 1).

  On the other hand, a configuration in which two laser light emitters are provided at the distal end portion of the endoscope scope is known. The two laser beam emitters simultaneously irradiate the laser beams so that the emitted laser beams intersect on the object to be observed. The endoscope apparatus measures the distance between the distal end of the endoscope scope and the observation object from the emission angle of the laser light (Patent Document 2).

JP 58-81021 A JP 2005-278980 A

  However, in the configuration in which a plurality of spot lights are irradiated, the plurality of spot lights must be emitted simultaneously or sequentially. In the case of simultaneous light emission, a plurality of light emitting devices must be provided, and there is a drawback that the device is large and complicated. When light is emitted sequentially, there is a disadvantage that the measurement time becomes long and the load on the subject increases.

  Further, when two laser light emitters are provided at the distal end portion of the endoscope scope, the distal end portion is enlarged. In order to reduce the burden on the subject, the distal end of the endoscope scope must be miniaturized. It is practically difficult to provide two laser light emitters at such a distal end.

  The present invention has been made in view of these problems, and an object of the present invention is to obtain an endoscope apparatus capable of displaying the distance between an observation object and an endoscope distal end portion.

  An endoscope apparatus according to the present invention is an endoscope apparatus that observes an observation object by bringing the distal end of the endoscope scope close to the observation object, and is provided at the distal end and images the observation object. An imaging unit that outputs an observation image, a laser beam emitting unit that is provided at the distal end and irradiates one laser beam toward the observation object, and a laser beam irradiated to the observation object in the observation image And a calculation unit that calculates the distance from the observation object to the distal end using the distance from the bright spot to the center of the observation image.

  The endoscope apparatus further includes a storage unit, the imaging unit images the target and outputs a target image, and the calculation unit calculates the distance between a plurality of arbitrary measurement points in the target image and the target to the distal end. Before observing the observation object, the storage unit stores the correspondence before observing the observation object, and the calculation unit calculates the distance from the observation object to the distal end. It is preferable to calculate the distance using the correspondence relationship.

  The laser beam emitting unit irradiates the target with laser beam, the measurement point is the bright spot of the laser beam irradiated to the target and the center of the target image, and the calculation unit irradiates the target in the target image The correspondence relationship between the distance from the bright spot of the laser beam thus obtained to the center of the target image and the distance from the target to the distal end may be calculated before observing the observation object.

  The imaging unit images a predetermined figure in which a plurality of measurement points are regularly arranged on a plane and outputs a target image, and the calculation unit calculates a distance between the measurement points in the target image and a distal end from the target. It is preferable to calculate the correspondence with the distance to the distance before observing the observation object.

  The endoscope apparatus further includes a storage unit, the laser beam emitting unit irradiates laser light toward the target, the imaging unit images the target via the imaging lens and outputs a target image, and the calculation unit includes The distance from the center of the imaging unit to the laser beam emitting unit, the distance from the imaging unit to the imaging lens, the distance from the bright spot of the laser beam irradiated to the target in the target image to the center of the target image, and the photographing lens The distance from the target to the target is used to calculate the amount of deviation between the optical axis of the imaging lens and the center of the imaging unit, and the storage unit stores the amount of deviation before observing the observation object. It is preferable to calculate the distance from the observation object to the distal end using the correspondence and the amount of deviation.

  The endoscope apparatus further includes a storage unit, and the imaging unit images a predetermined figure in which a plurality of measurement points are regularly arranged on a plane via the imaging lens, and outputs a target image. Using the distance from the center of the imaging unit to the laser beam emitting unit, the distance from the imaging unit to the imaging lens, the distance from the measurement point in the target image to the center of the target image, and the distance from the imaging lens to the target The amount of deviation between the optical axis of the imaging lens and the center of the imaging unit is calculated, the storage unit stores the amount of deviation before observing the observation object, and the calculation unit is from the observation object to the distal end. May be calculated using the correspondence and the amount of deviation.

  The endoscope apparatus further includes a storage unit, the laser beam emitting unit irradiates a plurality of laser beams toward the target, and the imaging unit images the target via the imaging lens and outputs a target image to calculate The unit calculates the distortion of the imaging lens by using the distances between the plurality of bright spots of the laser light irradiated to the target in the target image, and the storage unit calculates the distortion of the imaging lens before observing the observation object. Preferably, the calculation unit calculates the distance from the observation object to the distal end using the correspondence relationship and the distortion of the imaging lens.

  The endoscope apparatus further includes a storage unit, and the imaging unit images a predetermined figure in which a plurality of measurement points are regularly arranged on a plane via the imaging lens, and outputs a target image. The distortion of the imaging lens is calculated using the distances between the plurality of measurement points in the target image, the storage unit stores the distortion of the imaging lens before observing the observation object, and the calculation unit is the observation object. The distance from the distal end to the distal end may be calculated using the correspondence relationship and the distortion of the imaging lens.

  The predetermined figure is preferably a dot chart in which a plurality of measurement points are regularly arranged on a plane.

  The predetermined figure may be a lattice pattern in which straight lines are arranged on a plane in a lattice shape.

  The correspondence relationship is preferably LUT.

  The correspondence relationship may be a function in which the distance from the bright spot of the laser light irradiated to the target in the target image to the center of the target image is an independent variable, and the distance from the target to the distal end is a dependent variable.

  The calculation unit may calculate the size of the observation object according to the distance from the observation object to the distal end.

  It is preferable that the endoscope apparatus further includes a display device that displays the observation image, and the display device displays the distance calculated by the calculation unit.

  The display device may display an equidistant line corresponding to the distance calculated by the calculation unit on the observation image.

  The display device may display on the observation image a mesh line composed of a grid having a side with a predetermined length as one side according to the distance calculated by the calculation unit.

  The calculation unit calculates the size of the observation target according to the distance from the observation target to the distal end, and the display device displays the size of the observation target calculated by the calculation unit on the observation image. Also good.

  According to the present invention, an endoscope apparatus capable of displaying the distance between an observation object and an endoscope distal end is obtained.

It is the figure which showed the endoscope apparatus schematically. It is the figure which looked at the distal end part of the endoscope processor along the central axis from the outside. It is the figure which showed the 1st distance display. It is the figure which showed the endoscope scope fixed to the initial setting apparatus. It is the figure which showed the target. It is the figure which showed the target image. It is the figure which showed the relationship between the bright spot on a target, and the distance to a target. It is the figure which showed LUT. It is the figure which showed the relationship between the distance from the distal end tip of an endoscope scope to an observation object, and the number of pixels of an image. It is the flowchart which showed LUT creation processing. It is the flowchart which showed the distance measurement process. It is the figure which showed the target image when the optical axis of an imaging lens and the center point of CCD correspond. It is the figure which showed the target image from which the optical axis of an imaging lens and the center point of CCD do not correspond. It is the figure which showed roughly the shift | offset | difference of the optical axis of an imaging lens, and the center point of an image pick-up element. It is the figure which showed the relationship between the position on an observation image, and distortion. It is the figure which showed the target. It is the flowchart which showed the scale display process. It is the flowchart which showed the scale composition process. It is the figure which showed the 2nd distance display. It is the figure which showed the 3rd distance display.

  Hereinafter, an endoscope apparatus 10 according to a first embodiment of the present invention will be described with reference to the accompanying drawings. First, the configuration of the endoscope apparatus 10 will be described with reference to FIGS.

  The endoscope apparatus 10 includes an endoscope scope 20 that is inserted into a subject's body, an endoscope processor 30 that is provided outside the subject's body and performs image processing, and a monitor 40 that is connected to the endoscope processor 30. And mainly.

  The distal end portion 21 of the endoscope scope 20 is inserted into the body of the subject. The distal end portion 21 is mainly provided with an image pickup lens 22, a CCD 23 forming an image pickup portion, and a laser fiber 24 forming a laser light emitting portion.

  The distal end 21 has a cylindrical shape having a central axis K. The CCD 23 includes an imaging surface 28 and outputs an image of 1280 pixels in the horizontal direction and 1024 pixels in the vertical direction. The CCD 23 is arranged so that the center point Q of the imaging surface 28 is located on the central axis K. It is stored in the rear end 21. The imaging lens 22 and the CCD 23 are provided so that the optical axis of the imaging lens 22 is perpendicular to the imaging surface 28 and passes through the center point Q of the imaging surface 28. As a result, the optical axis of the imaging lens 22 overlaps the central axis K. Then, the CCD 23 images a subject via the imaging lens 22 and transmits an observation image obtained thereby to the endoscope processor 30 via the signal line 25.

  The endoscope scope 20 includes a connector (not shown), and is connected to the endoscope processor 30 via the connector. A memory 26 is provided inside the connector. The memory 26 stores various values described later, that is, correspondence relationships.

  The laser fiber 24 extends from the distal end 21 to the connector, receives laser light from the endoscope processor 30 and carries it to the distal end 21. The end of the laser fiber 24 provided at the distal end 21 is referred to as an irradiation end 27. The irradiation end 27 irradiates the observation target with laser light. The laser fiber 24 is provided so that the laser beam to be irradiated is parallel to the central axis K of the distal end portion 21. When the distal end portion 21 is viewed from the central axis K, the center of the irradiation end 27 is provided on the radially outer side of the center point Q of the imaging surface 28 (see FIG. 2).

  The endoscope processor 30 mainly includes a laser oscillator 31 that generates laser light, a calculation unit 32 that executes distance calculation processing described later, and a scale display unit 33 that synthesizes a first distance display 34 with an image. .

  The laser oscillator 31 irradiates the laser fiber 24 with laser light through a connector.

  The calculation unit 32 is connected to the CCD 23 and the memory 26, executes various processes described later, and outputs image data to the scale display unit 33.

  The scale display unit 33 synthesizes the first distance display 34 with the image data and outputs the image data to the monitor 40. The first distance display 34 indicates the size of the observation image with specific numerical values, and the second distance display 35 indicates the distance to the observation target object with specific numerical values (FIG. 3).

  Next, the initial setting device 50 of the endoscope apparatus 10 will be described with reference to FIGS. FIG. 4 is a view of the initial setting device 50 for fixing the distal end portion 21 of the endoscope scope 20 as viewed from above. FIG. 5 is a view of the target 52 attached to the initial setting device 50 as viewed from the distal end 21.

  When manufacturing the endoscope apparatus 10, in any endoscope apparatus 10, the laser fiber 24 and the CCD 23 are attached to the distal end 21 while the positional relationship among the laser fiber 24, the CCD 23, and the imaging lens 22 is always the same. Mounting is expensive and difficult due to tolerances. However, the error in the positional relationship between the laser fiber 24 and the CCD 23 is measured in advance using the initial setting device 50 and stored in the memory 26, thereby eliminating the error in the positional relationship between the laser fiber 24 and the image sensor. The distance can be measured.

  The initial setting device 50 mainly includes a fixing portion 51 that fixes the distal end portion 21 of the endoscope scope 20, a target 52, and a base portion 53 to which the fixing portion 51 and the target 52 are attached.

  The target 52 is a rectangle having a size corresponding to the angle of view of the endoscope scope 20, and reflects the laser light to the endoscope scope 20 appropriately. Two broken lines perpendicular to the center point O are drawn on the target 52 (see FIG. 5). One broken line extends in the long side direction of the target 52, and the other broken line extends in the short side direction of the target 52. The target 52 advances and retreats along the central axis K.

  The fixing portion 51 is positioned on the long axis drawn on the target 52 so that the center point O of the target 52 is located on the central axis K of the distal end portion 21 and the laser light emitted by the laser fiber 24 is drawn. As such, the distal end 21 is secured to the base 53. That is, the center point Q of the imaging surface 28 and the center point O of the target 52 are placed on the center axis K of the distal end portion 21.

  FIG. 6 is a view showing a target image taken by irradiating the laser beam onto the target 52. A point that shines when the irradiated laser is reflected on the target 52 is called a bright spot (laser spot). The target image is photographed so that the center point P of the target image matches the center point Q of the imaging surface 28. For the sake of explanation, three images obtained by photographing the laser bright spot Li, the laser bright spot Lii, and the laser bright spot Liii are shown as one image.

  When the distance from the distal end 21 to the target 52 is xi, the laser bright spot Li appears on the target 52, and when the distance from the distal end 21 to the target 52 is xii, the laser bright spot Lii is When it appears on the target 52 and the distance from the distal end 21 to the target 52 is xiii, the laser bright spot Liiii appears on the target 52.

  The size of the bright spot appearing on the target 52 decreases as the distance from the distal end 21 to the target 52 increases in the order of the laser bright spot Li, the laser bright spot Lii, and the laser bright spot Liii. The bright spot that appears in the image approaches the center point P of the target image. This is because as the target 52 moves away from the distal end portion 21, the area of the bright spot and the ratio of the distance from the bright spot to the center point P in the entire image become smaller.

  Therefore, the distance from the tip of the distal end portion 21 to the target 52 can be measured using the distance from the center point P of the target 52 to the center of the bright spot in the target image. The distance calculation means will be described with reference to FIG. In the endoscope apparatus 10 according to the present embodiment, the distal end surface of the distal end portion 21 coincides with a main plane that passes through the main point of the lens and is perpendicular to the optical axis.

Laser light is irradiated in parallel with the central axis K of the distal end portion 21. The bright line of the laser beam is indicated by L, the distance between the center point Q of the imaging surface 28 and the tip of the laser fiber 24 is t, the distance between the imaging surface 28 of the CCD 23 and the main plane of the lens is s, and measured from the main plane of the lens. The distance to the object A is xa, and the distance from the center point Q of the imaging surface 28 to the image A ′ is ya. Since the central axis K of the distal end portion 21 overlaps the optical axis of the imaging lens 22, and is perpendicular to the imaging surface 28 of the CCD 23 and passes through the center point Q of the imaging surface 28, the distance xa is given by the following equation: Desired.
xa = s · t / ya (1)
Here, the distances t and s are values inherent to the endoscope scope 20, and are measured and recorded in advance. The distance ya can be calculated when the CCD 23 images the observation object. The distance xb from the main plane of the lens to the measurement object B is also obtained in the same manner.

  The LUT shown in FIG. 8 is calculated using this equation. The LUT is created by executing a later-described LUT creation process before shipment of the endoscope apparatus 10 and stored in the memory 26. The LUT is used when measuring the distance in use.

  This LUT indicates the distance from the distal end 21 to the target 52 corresponding to the number of pixels from the center point O of the target 52 to the center point of the bright spot. For example, when the number of pixels from the center point O of the target 52 to the center point of the bright spot is 697 pixels, the distance from the distal end 21 tip to the target 52 is 4 mm. Similarly, the distance is 12 mm when the number of pixels is 232 pixels, and the distance is 24 mm when the number of pixels is 116 pixels.

  On the other hand, using a function F in which the distance ya from the center point O of the target 52 to the center point of the bright spot in the image is an independent variable and the distance xa from the tip of the distal end 21 to the target 52 is a dependent variable, It is also possible to measure the distance xa from the distal end portion 21 tip to the target 52. The function F is obtained by obtaining the distance xa for the measurement objects at different distances using the above-described equation (1) and creating an approximate expression for the distance xa and the distance ya. That is, the function F is obtained by creating an approximate expression for the values constituting the LUT. FIG. 9 shows a graph of this function F. The function F is created using an LUT creation process described later and stored in the memory 26 before the endoscope apparatus 10 is shipped. The endoscope apparatus 10 measures the distance from the tip of the distal end portion 21 to the target 52 using this function F based on the number of pixels from the center point O of the target 52 to the center point of the bright spot. To do. Since the measurement method is the same as that of the LUT, the description is omitted.

  Next, a means for calculating the size of the observation object will be described. The angle of view of the endoscope scope 20 is kept constant according to the specifications of the CCD 23 and the imaging lens 22. Therefore, if the distance to the observation object is known, the size of the observation object can be calculated from the ratio of the subject image to the observation image. The second distance display 35 indicates the size of the observation object using the distance from the observation object obtained by the above-described means.

  Next, the LUT creation process will be described with reference to FIG. The LUT creation process is a process executed by the calculation unit 32 before actual observation, for example, before shipment. Here, the minimum measurement distance, that is, the shortest measurable distance between the tip of the distal end 21 and the observation object is 1 mm, and the maximum measurement distance, that is, the longest measurement between the tip of the distal end 21 and the observation object. The description will be made assuming that the possible distance is 50 mm and the measurement interval is 1 mm. The minimum measurement distance, the maximum measurement distance, and the measurement interval are determined according to the specifications of the endoscope apparatus 10.

  First, in step S91, the target 52 is moved, and the distance from the tip of the distal end portion 21 to the target 52 is set to 1 mm. Then, the target 52 is irradiated with laser light.

  Next, in step S92, an observation image is acquired using the CCD 23.

  In step S93, the position of the bright spot included in the observation image is acquired.

  In the next step S94, the number of pixels from the center point P of the observation image to the center point of the bright spot is calculated and stored in the memory 26.

  In step S95, it is determined whether or not to end the process. If the distance from the tip of the distal end portion 21 to the target 52 is less than 50 mm, the process returns to step S91, and if it is 50 mm or more, the process ends.

  If the process proceeds to step S91 in step S95, the distance from the tip of the distal end portion 21 to the target 52 is increased by 1 mm and set to 2 mm in step S91. And the process from step S92 to S95 is repeatedly performed until the distance from the front-end | tip of the distal end part 21 to the target 52 becomes 50 mm.

  As a result, an LUT is created. In the LUT shown in FIG. 8, the case where the distance from the tip of the distal end portion 21 to the target 52 is 1 mm to 3 mm and 26 mm to 50 mm is omitted.

  In step S91 of the LUT creation process, the initial measurement value and the measurement interval are not limited to 1 mm, and the maximum measurement distance is not limited to 50 mm.

  Next, the distance measurement process will be described with reference to FIG. The distance measurement process is executed in the calculation unit 32 and the scale display unit 33 when the laser oscillator 31 emits a laser, that is, when laser light is emitted from the laser fiber 24.

  In step S101, an observation image is acquired using the CCD 23.

  In step S102, the center point coordinates of the bright spot (laser spot) included in the observation image are acquired.

  In the next step S103, the number of pixels from the center point coordinates of the CCD 23 to the center point coordinates of the bright spot, that is, the number of pixels from the center point P of the observation image to the center point of the bright spot is calculated and stored in the memory 26. To do.

  In step S104, the nearest pixel number is searched from the LUT, and the distance corresponding to the pixel number is read out.

  In step S105, the size of the observation object is calculated from the ratio of the subject image to the observation image using the distance read in step S104. Then, the first distance display (scale) 34 corresponding to the distance read in step S104 and the second distance display (scale) 35 corresponding to the calculated size of the observation object are combined with the observation image. Then, the observation image is transmitted to the monitor 40, and the monitor 40 displays the observation image.

  By repeatedly executing the processing from step S101 to S105 every several milliseconds, the distance between the distal end portion 21 of the endoscope scope 20 and the observation site and the size of the observation image are periodically updated. And displayed on the monitor 40.

  According to this embodiment, since the bright spot of the laser beam is provided at the position where the distance is measured, the operator can accurately grasp the position where the distance is measured. In addition, the distance accuracy can be improved by creating LUTs for more measurement points. Furthermore, since distance measurement can be performed simultaneously with observation, it is not necessary to provide time for distance measurement separately from observation, thereby reducing the examination time and reducing the burden on the subject.

  Even if the optical axis of the imaging lens 22 is not provided so as to be perpendicular to the imaging surface 28 of the CCD 23 and pass through the center point Q of the imaging surface 28 due to tolerances, the distance to the observation object is also provided. Can be measured accurately.

  Next, a second embodiment will be described with reference to FIGS. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the present embodiment, due to tolerance, the optical axis of the imaging lens 22 is not provided so as to be perpendicular to the imaging surface 28 of the CCD 23 and pass through the center point Q of the imaging surface 28. Therefore, in such a case, a means for measuring the distance to the measurement object will be described. Here, the laser fiber 24 is positioned so that the irradiation end 27 is on a plane passing through the central axis K of the distal end portion 21, and the irradiated laser light is parallel to the central axis K of the distal end portion 21. It shall be provided.

  It is often difficult in production technology to provide the imaging lens 22 with respect to the CCD 23 so that the optical axis of the imaging lens 22 is perpendicular to the imaging surface 28 of the CCD 23 and passes through the center point Q of the imaging surface 28. On the other hand, actual observation is sufficiently possible even if the imaging lens 22 is not so provided for the CCD 23. Therefore, there is an endoscope apparatus 10 in which the optical axis of the imaging lens 22 is not slightly perpendicular to the imaging surface 28 of the CCD 23 and does not pass through the center point Q of the imaging surface 28 slightly. A deviation between the optical axis of the imaging lens 22 and the center point Q of the imaging surface 28 is referred to as a lens center deviation. When there is a lens center shift, the premise of the above equation (1) is lost, and therefore the distance xa cannot be accurately obtained using the above equation (1).

  In addition, like the distal end portion 21 of the endoscope scope 20, there are many small lenses that must be accommodated in a narrow space, and small lenses tend to have distortion. However, if the means described below is used, the distance to the measurement object can be measured while eliminating the lens center shift and distortion.

  First, the lens center shift will be described with reference to FIGS.

  FIG. 12 shows a target image obtained by photographing the target 52 using the endoscope scope 20 fixed to the initial setting device 50 when there is no lens center shift. Endoscope so that the center point O of the target 52 is positioned on the central axis K of the distal end 21, that is, on a straight line passing through the center point Q of the imaging surface 28 and perpendicular to the imaging surface 28 of the CCD 23. The scope 20 is fixed to the initial setting device 50.

  The target image has a plurality of reference points arranged in a line at the center in the horizontal direction and the vertical direction. The size of the reference point located at the center point P of the target image is the largest, and the size of the reference point decreases as it approaches the outer periphery of the target image. When there is no lens center shift, a reference point located at the center point O of the target 52 forms an image at the center point Q of the imaging surface 28.

  FIG. 13 shows a target image obtained by photographing the target 52 using the endoscope scope 20 fixed to the initial setting device 50 when there is a lens center shift. Endoscope so that the center point O of the target 52 is positioned on the central axis K of the distal end 21, that is, on a straight line passing through the center point Q of the imaging surface 28 and perpendicular to the imaging surface 28 of the CCD 23. The scope 20 is fixed to the initial setting device 50. Here, the reference point located at the center point O of the target 52 is shifted from the center point Q of the imaging surface 28 due to the lens center shift, and an image is formed.

  FIG. 14 is a diagram illustrating a lens center deviation amount δ that is a deviation amount between the optical axis of the imaging lens 22 and the center point Q of the imaging surface 28. A means for calculating the lens center deviation amount δ will be described.

Laser light is irradiated in parallel with the central axis K of the distal end portion 21 from the endoscope scope 20 fixed to the initial setting device 50. The bright line of the laser beam is indicated by L, the distance between the center point Q of the imaging surface 28 and the tip of the laser fiber 24 is t, the distance between the imaging surface 28 of the CCD 23 and the main plane of the lens is s, and measured from the main plane of the lens. The distance to the object A is xc, and the distance from the center point Q of the imaging surface 28 to the image C ′ is yc. The lens center deviation amount δ is obtained by the following equation.
δ = (s · t · (t + x) −xc · yc) / (t + xc) (2)

  Since the endoscope scope 20 is fixed to the initial setting device 50, the distance xc from the tip of the distal end portion 21 to the target 52 is known. The distances t and s are also values inherent to the endoscope scope 20 and are measured in advance and are known. The distance yc can be calculated by imaging the target 52 with the CCD 23. Therefore, the lens center deviation amount δ is obtained. The lens center deviation amount δ is measured at the time of manufacture and stored in the memory 26.

  The lens center deviation amount δ may be measured for a plurality of different distances. A more accurate value can be obtained by taking an average of all the measured lens center deviation amounts δ.

  Alternatively, the lens center deviation amount δ may be measured by photographing the target 52 on which an orthogonal lattice pattern or a plurality of circular reference points are drawn. By treating the intersection and reference point of the orthogonal grid as the bright spot of the laser beam and treating the distance from the point on the target 52 corresponding to the center point P of the observation image to the intersection or reference point of the orthogonal grid as the distance s, the lens The center deviation amount δ can be obtained.

  Next, the distortion of the imaging lens 22 will be described with reference to FIGS.

  The imaging lens 22 has distortion as shown in FIG. A curve α indicates distortion when there is no lens center shift. A curve β is a curve obtained by translating the curve α by the lens center deviation δ, and shows distortion when the lens center deviation δ exists. Distortion is unique to the lens and is measured at the time of manufacture and stored in the memory 26. In addition, the lens center deviation amount δ can be calculated using Expression (2).

  Distortion measuring means will be described with reference to FIGS.

  First, the endoscope scope 20 is fixed to the initial setting device 50. Then, the target 52 is provided at a specific position. The target 52 has a plurality of reference points arranged in a line at the center in the horizontal direction and the vertical direction. The sizes of the reference points are all equal, and the intervals between the reference points are equal (see FIG. 16).

  Next, the target 52 is imaged using the CCD 23 to obtain a target image as shown in FIG. In the target image, the size of the reference point located at the center point P of the target image is the largest, and the size of the reference point decreases as it approaches the outer periphery of the target image. A reference point located at the center point P of the target image forms an image at the center point Q of the imaging surface 28.

  Next, intervals d1, d2, d3, and d4 between reference points in the target image are measured. The unit of these intervals is expressed in pixels.

  Then, an approximate expression for distortion is obtained using the intervals d1, d2, d3, and d4. Distortion can be obtained while keeping the number of intervals to be measured small.

  Note that the distortion may be created by regarding a plurality of bright spots generated by irradiating a plurality of positions of the target 52 with laser light as reference points. At this time, the laser light is irradiated at equal intervals as in a dot chart. Alternatively, distortion may be created by photographing the target 52 on which an orthogonal lattice pattern is drawn. The intersection of the orthogonal grid is considered as a reference point.

  The number for measuring the interval is not limited to four. By measuring the distance between more reference points, the distortion can be accurately determined.

  Next, the scale display process will be described with reference to FIGS. The scale display process is executed in the calculation unit 32 and the scale display unit 33 when the laser oscillator 31 emits a laser in use, that is, when laser light is emitted from the laser fiber 24.

  In step S171, an observation image is acquired using the CCD 23.

  In step S172, the center point coordinates of the bright spot (laser spot) included in the observation image are acquired.

  In the next step S173, the number of pixels from the center point coordinates of the CCD 23 to the center point coordinates of the bright spot, that is, the number of pixels from the center point P of the observation image to the center point of the bright spot is calculated and stored in the memory 26. To do.

  In step S174, the lens center deviation amount δ and the approximate expression for distortion are read from the memory 26.

  In the next step S175, the distance corresponding to the number of pixels is calculated by applying an approximate expression of the lens center deviation amount δ and distortion to the number of pixels calculated in step S173.

  In step S176, scale composition processing described later is executed, and a third distance display (scale) 36 corresponding to the distance calculated in step S175 is synthesized with the observation image (see FIG. 19). Thereafter, the observation image is transmitted to the monitor 40, and the monitor 40 displays the observation image.

  By repeatedly executing the processing from steps S171 to S176 every several milliseconds, the distance between the distal end portion 21 of the endoscope scope 20 and the observation site is periodically updated and displayed on the monitor 40. Is done.

  Next, the scale composition process will be described with reference to FIGS. The scale composition process is executed by the calculation unit 32 and the scale display unit 33 in step S176 of the scale display process.

  In step S181, the distance calculated in step S175 of the scale display process is used to calculate how many pixels the actual length of 1 mm on the observation object is.

  In step S182, a basic length display is created from the number of pixels calculated in step S181. The basic length display created here is composed of a plurality of curves.

  In the next step S183, the basic length display is converted into the third distance display 36 in consideration of the distortion by using the distortion approximate expression.

  In step S184, the third distance display 36 is combined with the observation image (see FIG. 19). The second distance display is an equidistant line connecting points having the same distance from the center of the observation image. Thereafter, the process returns to the scale display process.

  In the present embodiment, an orthogonal lattice may be used as the basic length display, and this may be converted into the fourth distance display 37 by an approximate expression of distortion (see FIG. 20). The third distance display is a mesh line composed of squares with one side having a predetermined length as one side, and one side forming one square indicates a predetermined length of the observation object, and one square is predetermined. Indicates the area. Thereby, the surgeon can know the area of the site to be observed.

  According to the present embodiment, the operator can know the distance between the observation object and the endoscope tip at any location in the observation image.

  In the second embodiment, the second distance display 35 may be displayed simultaneously with the third distance display 36 and the fourth distance display 37, and the distance from the observation object may be indicated by a specific numerical value. Good.

  The CCD 23 may output an image other than 1024 pixels in the horizontal direction and 768 pixels in the vertical direction.

  The imaging unit is not limited to the CCD 23, and may be an imaging element such as a CMOS.

  The target 52 is not limited to a rectangle, but may be another shape such as a circle.

DESCRIPTION OF SYMBOLS 10 Endoscope apparatus 20 Endoscope scope 21 Distal end part 22 Imaging lens 23 CCD
24 Laser fiber 25 Signal line 26 Memory 27 Irradiation end 28 Imaging surface 30 Endoscope processor 31 Laser oscillator 32 Calculation unit 33 Scale display unit 34 First distance display 35 Second distance display 36 Third distance display 37 Fourth Distance display 40 Monitor 50 Initial setting device 51 Fixed part 52 Target 53 Base

Claims (17)

An endoscope apparatus for observing an observation object by bringing the distal end of the endoscope scope close to the observation object,
An imaging unit provided at the distal end for imaging an observation object and outputting an observation image;
A laser beam emitting section that is provided at the distal end and irradiates one laser beam toward the observation object;
An endoscope comprising: a calculation unit that calculates a distance from the observation object to the distal end using a distance from a bright spot of a laser beam irradiated to the observation object in the observation image to a center of the observation image Mirror device. The endoscope apparatus further includes a storage unit,
The imaging unit images a target and outputs a target image;
The calculation unit calculates the correspondence between the distance between a plurality of arbitrary measurement points in the target image and the distance from the target to the distal end before observing the observation object,
The storage unit stores the correspondence before observing the observation object,
The endoscope apparatus according to claim 1, wherein the calculation unit calculates a distance from an observation object to the distal end using the correspondence relationship. The laser light emitting unit irradiates a target with laser light,
The measurement point is a bright spot of laser light irradiated on the target and the center of the target image,
The calculation unit calculates a correspondence relationship between the distance from the bright spot of the laser light irradiated to the target in the target image to the center of the target image and the distance from the target to the distal end, and the observation object. The endoscope apparatus according to claim 2, wherein the endoscope apparatus is calculated before observation. The imaging unit images a predetermined figure in which a plurality of measurement points are regularly arranged on a plane and outputs a target image,
The internal unit according to claim 2, wherein the calculation unit calculates a correspondence relationship between a distance between the measurement points in the target image and a distance from the target to the distal end before observing the observation object. Endoscopic device. The endoscope apparatus further includes a storage unit,
The laser light emitting unit irradiates a target with laser light,
The imaging unit images a target through an imaging lens and outputs a target image;
The calculation unit includes a distance from the center of the imaging unit to the laser light emitting unit, a distance from the imaging unit to the imaging lens, and a bright spot of laser light irradiated on the target in the target image. Using the distance to the center of the image and the distance from the photographing lens to the target, the amount of deviation between the optical axis of the imaging lens and the center of the imaging unit is calculated,
The storage unit stores the shift amount before observing the observation object;
The endoscope apparatus according to claim 1, wherein the calculation unit calculates a distance from an observation object to the distal end using the correspondence relationship and the shift amount. The endoscope apparatus further includes a storage unit,
The imaging unit outputs a target image by imaging a predetermined figure in which a plurality of measurement points are regularly arranged on a plane via an imaging lens,
The calculation unit includes a distance from the center of the imaging unit to the laser light emitting unit, a distance from the imaging unit to the imaging lens, and a distance from the measurement point in the target image to the center of the target image. , Using the distance from the photographing lens to the target, to calculate the amount of deviation between the optical axis of the imaging lens and the center of the imaging unit,
The storage unit stores the shift amount before observing the observation object;
The endoscope apparatus according to claim 1, wherein the calculation unit calculates a distance from an observation object to the distal end using the correspondence relationship and the shift amount. The endoscope apparatus further includes a storage unit,
The laser beam emitting unit irradiates a plurality of laser beams toward a target,
The imaging unit images a target through an imaging lens and outputs a target image;
The calculation unit calculates the distortion of the imaging lens using the distances between the plurality of bright spots of the laser light irradiated to the target in the target image,
The storage unit stores distortion of the imaging lens before observing the observation object,
The endoscope apparatus according to claim 1, wherein the calculation unit calculates a distance from an observation object to the distal end using the correspondence relationship and distortion of the imaging lens. The endoscope apparatus further includes a storage unit,
The imaging unit outputs a target image by imaging a predetermined figure in which a plurality of measurement points are regularly arranged on a plane via an imaging lens,
The calculation unit calculates the distortion of the imaging lens using a distance between a plurality of measurement points in the target image,
The storage unit stores the distortion of the imaging lens before observing the observation object,
The endoscope apparatus according to claim 1, wherein the calculation unit calculates a distance from an observation object to the distal end by using the correspondence relationship and distortion of the imaging lens.   The endoscope apparatus according to claim 4, 6, or 8, wherein the predetermined figure is a dot chart in which a plurality of measurement points are regularly arranged on a plane.   The endoscope apparatus according to claim 4, 6, or 8, wherein the predetermined figure is a lattice pattern in which straight lines are arranged on a plane in a lattice shape.   The endoscope apparatus according to claim 2, wherein the correspondence relationship is an LUT.   The correspondence is a function in which the distance from the bright spot of the laser beam irradiated to the target in the target image to the center of the target image is an independent variable, and the distance from the target to the distal end is a dependent variable. The endoscope apparatus according to any one of claims 2 to 4.   The endoscope apparatus according to claim 1, wherein the calculation unit calculates the size of the observation object according to a distance from the observation object to the distal end. The endoscope apparatus further includes a display device that displays the observation image,
The endoscope apparatus according to claim 1, wherein the display device displays a distance calculated by the calculation unit.   The internal view according to claim 14, wherein the display device displays equidistant lines on the observation image by connecting points having the same distance from the center of the observation image according to the distance calculated by the calculation unit. Mirror device.   The endoscope apparatus according to claim 15, wherein the display device displays a mesh line including a grid having a side having a predetermined length as one side on the observation image according to the distance calculated by the calculation unit. . The calculation unit calculates the size of the observation object according to the distance from the observation object to the distal end,
The endoscope apparatus according to any one of claims 14 to 16, wherein the display device displays the size of the observation object calculated by the calculation unit on the observation image.

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