JP3268895B2 - Endoscope device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope apparatus for measuring a gap by using a light section method.

[0002]

2. Description of the Related Art In recent years, by inserting an elongated insertion portion into a body cavity, it is possible to observe internal organs in the body cavity or to perform various treatments using a treatment tool inserted into a treatment tool channel as necessary. Endoscopes are widely used.

[0003] In the industrial field, industrial endoscopes are widely used for observing and inspecting scratches and corrosion inside boilers, turbines, engines, chemical plants and the like. Japanese Unexamined Patent Publication No. Hei 3-13805 discloses a means for measuring an object shape by a light cutting method in which linear contrast light is emitted from an illumination light source at the end of an endoscope. Also, Japanese Patent Application Laid-Open No. 62-7 / 1987
Reference numeral 3223 denotes a distance measuring unit using one laser beam.

[0004]

Problems to be Solved by the Invention
The light sectioning method described in (1) enables measurement of the length on a line, measurement of an object shape that smoothly changes without a break in the line, and measurement of a step that clearly corresponds to the broken line. However, when measuring the gap generated at the orthogonal portion of an object where two planes intersect at right angles, the correspondence of the broken line is not clear, and the gap cannot be measured.

The present invention has been made in view of the above circumstances, and is an endoscope apparatus capable of measuring the length of a gap where lines projected onto an object surface are discontinuous by a light cutting method using an endoscope. The purpose is to provide.

[0006]

When measuring a gap where a laser line becomes discontinuous in a light cutting method using an endoscope, at least one of the discontinuous lines is represented by an approximate expression, and the line is represented by an approximate expression. Is extrapolated to determine the intersection of the two lines to determine the length or distance of the gap.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. 1 to 13 relate to one embodiment of the present invention, FIG. 1 is an explanatory view of the entire configuration of an endoscope device, FIG. 2 is a cross-sectional view of an endoscope distal end, and FIG. FIG. 4 is a cross-sectional view of a laser line projection unit provided, FIG. 4 is a diagram illustrating a laser line light source, FIG. 5 is a block diagram of an endoscope apparatus, and FIG. 6 shows a state where a laser line is projected on an object plane parallel to the distal end surface. 7, FIG. 7 is an explanatory diagram of the relationship between the measurement points and the optical system at the AA cross-sectional position in FIG. 6, FIG. 8 is an explanatory diagram showing a state in which a laser line is projected on an oblique object surface at the tip end surface, 9 is a side view of FIG. 8, FIG. 10 is an explanatory view showing a captured image in FIG. 8, FIG. 11 is an explanatory view showing a relationship between a measurement point and an optical system in FIG. 8, and FIG. FIG. 13 is an explanatory diagram showing a state in which a laser line is projected onto the image, and FIG.

As shown in FIG. 1, an endoscope apparatus 1 according to the present embodiment
Is an electronic endoscope 2 having a built-in image pickup means, an illumination light source 3 to which the electronic endoscope 2 is connected and which supplies illumination light to the electronic endoscope 2, and an image pickup means of the electronic endoscope 2. It comprises a measuring unit 4 having a function of performing signal processing and measuring the length, and a laser light source 5 which is provided at a connection between the electronic endoscope 2 and the illumination light source 3 and generates laser light. I have.

The electronic endoscope 2 includes an elongated insertion section 6 having flexibility, an operation section 7 provided at a rear end of the insertion section 6,
And a universal cord 8 extending from the operation unit 7.
Connected to. An electric cable 9 extends from the laser light source 5 and is connected to the measuring unit 4.

The insertion portion 6 has a hard distal end portion 11 and a bendable bending portion 12 adjacent to the distal end portion 11, and is turned by turning a bending operation knob 13 provided on the operation portion 7. The part 12 can be curved.

A light guide (not shown) for transmitting illumination light is inserted into the insertion portion 6 and the universal cord 8 to transmit the illumination light supplied from the illumination light source 3 and to the two illumination windows 14 of the distal end portion 12. , 14, the transmitted illumination light is emitted forward through the illumination lens attached to the illumination lens, and illuminates the object surface 15 in front.

An observation window is provided adjacent to the illumination windows 14, 14, and this observation window has an objective lens system 1 as shown in FIG.
7 is attached. At the focal plane of the objective lens system 17, a CCD 18 is arranged.
An image pickup unit 19 for obtaining a picked-up image is formed by the control unit 8 and the image pickup unit 8.

A lead projecting from the back surface of the CCD 19 for converting an optical image formed by the objective lens system 17 into an electric signal is connected to a flexible substrate, which is bent and extends rearward. 2
The signal cable 20 is inserted from the operation unit 7 through the universal cord 8, and further connected to the measuring unit 4 via the electric cable 9.

As shown in FIG. 2, a laser line projection unit 21 is attached to a window formed adjacent to the observation window, and a laser beam transmitted through an optical fiber 22 is transmitted to a laser line projection lens system 23. Then, a linear laser beam, that is, a laser line is projected on the object surface 15 side ahead.

FIG. 3 is a sectional view of the laser line projection unit 21. Outgoing light from the distal end surface of the optical fiber 22 held by the base 24 is converted into parallel rays by the collimating lenses 25a and 25b, and then enters the cylindrical lens 26. The light emitted from the cylindrical lens 26 becomes light having a fan-like spread, and is emitted forward through the cover glass 27. FIG. 2 is a cross-sectional view in a direction orthogonal to FIG. 3, and in the cross section of FIG. 2, the laser light is emitted forward without spreading.

A laser light source unit 28 shown in FIG. The laser light source unit 28 includes a laser diode 30 and the collimating lens 3.
1, a condenser lens 32, and an optical fiber 22. Light from the laser diode 30 is converted into substantially parallel light by a collimating lens 31.

The substantially parallel light rays are condensed by the condenser lens 32 on the end face of the optical fiber 22 fixed by the base 29. The laser diode 30 is fixed to the lens frame 33. The lens frame 33 has radiation fins 34 for radiating heat from the laser diode 30.

Thus, the laser diode 30 is mounted on the lens frame 33, and the radiation fins 3 are further mounted on the lens frame 33.
By providing the laser light source 4, the laser light source 5 can be reduced in size.

FIG. 5 is a block diagram of a signal processing system of the endoscope apparatus 1. The CCD 18 built in the electronic endoscope 2 is C
It is driven by the CU 35 and becomes an image signal. After the image is written into the frame memory 36, it is displayed on the CRT 37. The frame memory 36 is accessed by the CPU 38, and measurement described later is performed.

A laser diode 30, which is a light source of the laser line, is driven by a laser diode drive circuit 39. The CPU 38 reads the intensity of the laser line from the frame memory 36 and issues an instruction to the laser diode drive circuit 39 to obtain appropriate brightness. CPU3
Reference numeral 8 is connected to the keyboard 40, and when measuring from the keyboard 40, inputs such as designation of the position of a measurement point.

In response to a measurement instruction from the keyboard 40, the CPU 38 calculates an approximate expression passing through a plurality of measurement points, which will be described later,
Measurement processing such as calculation for finding the intersection of the two approximate expressions and calculation of the gap length is performed.

FIGS. 6 and 7 show the principle of measurement. As shown in FIG. 6, the fan-shaped light emitted from the laser line projection unit 21 draws a laser line 41 on the object surface 15. FIG. 7 shows an AA cross section of FIG. The dotted line in FIG. 7 indicates the visual field range.

The entrance pupil position of the objective lens system 17 is O, the emission position of the laser line projection unit 21 is R, the point on the laser line 41 projected on the object plane 15, and the point in the AA cross section is P. The angle between the optical axis and OP is defined as θ. The distance RP from the laser line emission position R to the object plane is L
Then, this L is obtained by L = H * tan (90-θ) (1). Here, H indicates the OR distance. FIG.
, The point P is imaged at the point p on the imaging surface 18a of the CCD 18.

FIG. 8 shows a state in which the laser line 41 is projected on an oblique plane Π. FIG. 9 shows a side view thereof. FIG.
Represents an image of the measurement points P0 and P1 on the laser line 41 in FIG. 8 or FIG. FIG.
(A) and (b) are explanatory diagrams for obtaining a relational expression of length measurement when each measurement point P0, P1 is imaged using an optical system.

A coordinate system having the optical center as the origin O of three-dimensional coordinates is set. For easy understanding, the Z axis of the three-dimensional coordinates is set in the direction of the optical axis, and the two-dimensional coordinate plane is moved on the two-dimensional coordinate plane on the optical axis, and the two-dimensional coordinates arranged on the measurement point side are imaged with (X, Y) The two-dimensional coordinates arranged on the side are indicated by (x, y).

In this case, the origin Op on the measurement point side is Z0 (in the case of point P0) or Z1 on the optical axis from the origin O of the three-dimensional coordinates.
(In the case of point P1) At the moved position, the origin om on the imaging side is shifted from the origin O of the three-dimensional coordinates to the focal length f
It exists at the moved position, and the x and X axes and the y and Y axes are both parallel. In this embodiment, x or the X coordinate is R
And O are connected.

It is assumed that the image on the image pickup surface 18a of the CCD 18 is stored in the frame memory 36 as it is. Therefore, when the measurement points P0 and P1 on the laser line 41 are imaged,
The corresponding points on the frame memory 36 are p0 and p1.

As shown in FIG. 11, measurement points P0, P
Assuming that the coordinates of 1 are (X0, Y0) and (X1, Y1), the coordinates of the corresponding points p0 and p1 on the frame memory 36 are (x0, y0) and (x1, y1), respectively, as shown in FIG.
). Also, since the x or X axis is set in the direction connecting R and O, in FIG. 11, Op-X0, Op-X
The length of 1 is H.

On the frame memory 36, the angle between the line connecting the origin om and the measurement point (image of P0) p0 and the x-axis is α0,
Let α1 be the angle formed by the line connecting the origin om and the measurement point (image of P1) p1 with the x-axis. The maximum angle of view of the image is θg, and the coordinates on the frame memory 36 are (xg, yg).

When the optical system has a SIN θ type distortion, the angles θ 0 ′, θ 1 ′, θ 0, and θ 1 shown in FIGS. 11A and 11B are obtained by the following equations.

Θ 0 ′ = sin ⁻¹ {x0 * sin (θg) / sqr (xg ² + yg ² )} (2) θ ¹ ′ = sin ⁻¹ {x1 * sin (θg) / sqr (xg ² + yg ² )} ^{θ0 = sin -1 {sqr (x0} 2 + y0 2) * sin (θg) / sqr (xg 2 + yg 2)} (2 ') θ1 = sin -1 {sqr (x1 2 + y1 2) * sin (θg) / ^{sqr (xg 2 + yg 2)} } where, for example, sqr (x0 ² + y0 ²⁾ represents the square root of (x0 ² + y0 ^2).

The distances L0 and L1 to the planes including the measurement points P0 and P1, respectively, are as follows: L0 = H * tan (90-.theta.0 ') (3) L1 = H * tan (90-.theta.1')

The distance s0 between Op-P0 and Op-P
The distance s1 between 1 is s0 = L0 * tan (.theta.0) (4) s1 = L1 * tan (.theta.1).

Further, α0 and α1 are obtained by the following equations.

Α0 = tan ⁻¹ (y0 / x0) (5) α1 = tan ⁻¹ (y1 / x1) The three-dimensional coordinates of the measurement point P0 are X0 = s0 * cos (α0) (6) Y0 = s0 * Sin (α0) (7) Z0 = L0 (8)

The three-dimensional coordinates of the measurement point P1 are as follows: X1 = s1 * cos (α1) Y1 = s1 * sin (α1) Z1 = L1

The measurement point, the distance D between two points P0, P1 is determined by D = {(X0-X1) 2 + (Y0-Y1) 2 + (Z0-Z1) 2} 1/2 (9) .

FIG. 12 shows an object 4 having a gap G.
The case where a laser line is projected to measure the length (distance) of the gap in Nos. 2 and 43 is shown. FIG. 13 shows the endoscope image.

When a laser line is projected onto the gap, two laser lines 41a and 41b become discontinuous at the gap. One laser line 4 on the image
1a ', including the edge of the object 42, three points p0, p1,
Take p2.

The actual three points P0, p0, p1, p2,
The three-dimensional coordinates of P1 and P2 are represented by P0 (X0, Y0, Z0) P1 (X1, Y1, Z1) P2 (X2, Y2, Z2) from the calculation formulas shown in equations (1) to (8). .

[0041] through the P0, P1, and P2 in the least squares ^{_{method, y = t n x n +}} t n-1 x n-1 + ... + t 1 point by applying to the _{x + t 0 (10) P0} , P1, P2 ( An approximate expression of a curve (including the case of a straight line) is obtained, and the intersection of the curve of the approximate expression corresponding to a line extrapolating P0, P1, and P2 and the other laser line 41b is defined as P3. Here, t _i (i
= 0, 1,..., N) are coefficients and x is a variable representing coordinates.

If the distance between the measurement points P2 and P3 is obtained by the equation (9), the gap between the two objects can be obtained. As described above, when measuring an object whose one end of the gap is clear and the other end is unclear by the light cutting method, the discontinuous laser lines 41a,
By determining the intersection of 41b, the distance of the gap can be determined.

Taking three points P0, P1, P2 including the edge on the laser line 41a on the object 42, and taking the other object 43
It has been described that the intersection with the upper laser line 41b is obtained. However, in some cases, two points may be used instead of the three points P0, P1, and P2.
Points P0, P1 or four or more points P0, P1, P2, P3 or more may be used.

When an approximate expression representing the other laser line 41b is obtained, the approximate expression may be obtained by the least square method or the like. That is, an approximate expression that approximates each of the two laser lines that are discontinuous due to the gap may be determined, the intersection may be determined from the approximate expressions, and the distance to one edge and the intersection may be determined by Expression (9). .

As described above, by providing a system capable of measuring the gap endoscope, it is impossible to accurately measure the gap unless it is conventionally disassembled. The gap can be precisely measured without disassembling the engine.

Further, cracks and the like of an aged building can be measured. Another expression such as a spline function may be used as the approximate expression. A light emitting diode may be used instead of a laser diode.

Further, as shown in FIG. 8, the illumination unit is provided on one side with respect to the line connecting the imaging unit and the laser line projection unit, so that the illumination unit is located at a position separated from the object when measuring an inclined object surface. Can access the endoscope. Thereby, the laser line 41 at the near point does not become invisible due to the illumination light.

In FIG. 13, if the object 42 is extended so as to be in contact with the object 43, the line on each object becomes a continuous line (broken line), so that the intersection P3 must exist. If there is no such point, the point P3 may be the closest point between the approximate curve and the laser line 41b.

In the above description, the endoscope apparatus for measuring the gap using the light section method has been described. However, the present invention measures the gap using the light section method in steps S1 to S5 described below, for example. Measurement methods to be performed.

Step S1: A plurality of points including edges, p0, p1,..., On the image of one laser line on the imaging surface
... Set pm. That is, in two laser lines that are discontinuous due to the gap, a plurality of points including edges on the image of one laser line on the imaging surface corresponding to the position on one laser line, p0, p1,. ... Set pm. For example, the point pm
Is the edge position. .. Pm correspond to a plurality of measurement points P0, P1,... Pm on the object plane.

Step S2: a plurality of measurement points, P0, P1
,... Pm. That is, the three-dimensional coordinates of a plurality of measurement points P0, P1,... Pm are used, and an approximate expression y1 passing therethrough is determined by the least square method or the like.

Step S3: A plurality of points, p0, p1,... Pn ', are set on the image of the other laser line on the imaging plane. A plurality of points, p0 ', p1',... Pn ', correspond to a plurality of measurement points, P0', P1 ',.

Step S4: Plurality of measurement points, P0 ', P
An approximate expression passing through 1 ',... Pn' is obtained. That is, the three-dimensional coordinates of a plurality of measurement points, P0 ', P1',... Pn ', are used, and an approximate expression y2 passing therethrough is determined by the least square method or the like.

Step S5: The intersection Q of the two approximate expressions y1 and y2 is obtained, and the distance D between Pm and Q is calculated by the expression (9). Instead of obtaining two approximate expressions, an approximate expression of only one may be obtained, and a point at which this approximate expression intersects the other line may be obtained to obtain the length of the gap or the like.

When the image of one laser line or the other laser line can be approximated by a straight line, extrapolation is performed on the image by using a straight line ruler, a curve ruler, or the like, and the intersection is obtained. An interval or the like may be calculated. Instead of calculating a line for extrapolation, a formula of a plane extrapolated from an edge portion is calculated, and a length of a gap or the like is calculated by calculating a curve or the like that intersects with the other object surface. You may do it.

[0056]

As described above, when measuring the gap where the projected line becomes discontinuous in the light sectioning method using an endoscope, at least one of the discontinuous lines is represented by an approximate expression, and the line is represented by an approximate expression. Extrapolate to find the intersection of the two lines,
The length of the gap can be obtained by calculating the distance between the intersection and one end of the discontinuous line.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an endoscope apparatus according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a structure of a distal end portion of the endoscope.

FIG. 3 is a cross-sectional view of a laser line projection unit provided at the end of the endoscope.

FIG. 4 is a sectional view showing a laser line light source.

FIG. 5 is a block diagram of an electric system of the endoscope apparatus.

FIG. 6 is a diagram in which a laser line is projected on an object plane parallel to a front end surface.

FIG. 7 is an explanatory diagram of a relationship between a measurement point and an optical system at the position of the AA cross section in FIG. 6;

FIG. 8 is an explanatory diagram showing a state in which a laser line is projected on an object surface that is oblique to the tip end surface.

FIG. 9 is a side view of FIG. 8;

FIG. 10 is an explanatory diagram showing a captured image in FIG. 8;

FIG. 11 is an explanatory diagram showing a relationship between a measurement point and an optical system.

FIG. 12 is an explanatory diagram showing a state where a laser line is projected on two objects having a gap.

FIG. 13 is an explanatory diagram showing a captured image in FIG. 12;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Endoscope apparatus 2 ... Electronic endoscope 3 ... Illumination light source 4 ... Measuring unit 5 ... Laser light source 6 ... Insertion part 7 ... Operation part 8 ... Universal cord 9 ... Electric cable 11 ... Tip part 14 ... Lighting window 15 ... Object surface 17 ... Object lens system 18 ... CCD 19 ... Imaging unit 21 ... Laser line projection unit 22 ... Optical fiber 23 ... Laser line projection lens system 28 ... Laser light source unit 30 ... Laser diode 35 ... CCU 36 ... Frame memory 37 ... CRT 38 ... CPU 40 ... Keyboard 41a, 41b ... Laser line

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01B 11/00-11/30 102 A61B 1/00-1/32 G01N 21/84-21/958 G02B 23 / 24-23/26

Claims (1)

(57) [Claims] 1. An objective optical system for forming an image of an object to be inspected at a tip of an insertion portion, a line projection portion for projecting linear light onto an object surface, and a light cutting method using the line. In an endoscope apparatus having a function of measuring the length using, when measuring the gap where the line projected on the object plane is discontinuous, at least one of the discontinuous lines is represented by an approximate expression, and An endoscope that has a function of measuring the distance of the gap by extrapolating the represented line to determine the intersection of the two lines and calculating the distance between the intersection and one end of the discontinuous line. Mirror device.