JPH06109424A - Image sensing apparatus for measurement - Google Patents

Abstract

PURPOSE:To obtain a clear image of an object, which does not contain any external- disturbance light component by light-source light even when the relative position of an image sensing system to an external-disturbance light source is changed. CONSTITUTION:A beam of light 6 which is incident on a half mirror 7 arranged toward an object, which is irradiated with a beam of light from a laser light source is branched by the half mirror 7. A first CCD camera 12A photodetects a beam of light 11S transmitted through a first optical filter 9 which transmits only a beam of light whose wavelength is identical to that of the beam of light of the light-source. It senses the image of the object under test and an external-disturbance light image by a beam of light whose wavelength is identical to that of the beam of light of the light source out of beams of light from an external-disturbance light source. A second CCD camera 13A senses an external-disturbance light image by a beam of light 11R which has been transmitted through a second optical filter 10 which does not transmit the beam of light whose wavelength is identical to that of the light-source light. Brightness values of picture elements in the same address in both images are compared, and an external-disturbance light component in the images obtained by the first CCD camera 12A is removed. Thereby, the image of the object under test by the light-source light is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the shape of an object to be measured,
Regarding a measurement object imaging device used for optical measurement of dimensions, position, and the like, in detail, even when the position of the imaging system and the disturbance light source change relative to each other, the disturbance light component that becomes noise The present invention relates to a measurement target image pickup device capable of obtaining a clear measurement target image.

[0002]

2. Description of the Related Art A light cutting method is one of the optical measuring methods used for irradiating a measuring object with light from a light source and measuring the shape, size, position, etc. of the measuring object. As a conventional technique for obtaining an image of an object to be measured by applying this light cutting method, there is Japanese Patent Laid-Open No. 60-2001.
There is one shown in Japanese Patent Publication No. 03.

In this conventional technique, first, an image with slit projection light when a slit light source is turned on and a slit light is irradiated to an object to be measured is imaged by an imaging section equipped with a linear image sensor. , Images for one scan are obtained. The output of the linear image sensor for one scanning line at this time is an explanatory diagram of the basic principle.
(B) of FIG. Next, the slit light source is turned off, an image in the absence of slit projection light is captured by the image capturing unit, and an image for one scan is obtained. The output of the linear image sensor for one scanning line at this time is as shown in (c) of FIG. Then, the image processing apparatus sequentially captures the image with the slit projection light and the background image without the slit projection light, which are obtained in this way, and for the pixels at the same position, Find the difference between the image signal and the image signal of the background image (Fig.
16 (d)). According to this conventional technique, an image of a light cutting line generated by the irradiation of slit light in which the disturbance light component is removed is obtained by the difference signal.

[0004]

SUMMARY OF THE INVENTION The above-mentioned conventional technique provides an image with slit projection light when a slit light source as a light source is turned on and a background image with no slit projection light when the slit light source is turned off. The image is obtained in order and the difference between the image signals between the two images is obtained to obtain the image of the target optical cutting line. Therefore, according to the conventional technique, in the case where the image pickup system and the disturbance light source change in position relative to each other, in the image obtained when the light source is turned on and the image obtained when the light source is turned off. Since the position of the disturbance light image due to the disturbance light source is displaced, the disturbance light component is included in the measurement target image (corresponding to the light section line image in the above-mentioned conventional technique) obtained by obtaining the difference between the image signals between the two images. Is not completely removed and remains as a noise component. Therefore, there is a problem that the measurement accuracy of the measurement target object based on the image obtained by capturing the measurement target object is reduced.

The present invention has been made in order to solve the above-mentioned conventional problems. Even when the position of the image pickup system and the disturbance light source change relative to each other, the disturbance light becomes noise. An object of the present invention is to provide a measurement target image pickup device that can obtain a clear measurement target image by light from a light source without components.

[0006]

In order to achieve the above object, a measuring object image pickup device according to the present invention includes a light source for irradiating the measuring object with light in a narrow wavelength band, and a light source for irradiating the measuring object. An optical path branching optical system that branches the incident light, and a first optical filter that receives one of the light beams branched by the optical path branching optical system and that transmits only the light having the same wavelength as the light source light, A second optical filter that receives the other light branched by the optical path branching optical system and does not transmit the light having the same wavelength as the light source light but the light having a different wavelength from the light source light, and the first optical filter. First image pickup means for receiving the light passing through the filter to pick up an image including the measurement object, and a disturbance light image by the light passing through the second optical filter in synchronization with the first image pickup means. A second image capturing means for capturing an image; And the brightness values of pixels of the same address in both images obtained by the second image pickup means are compared, and the disturbance light component of the image obtained by the first image pickup means is removed based on the comparison result, And an image processing device that creates an image of a measurement object using light from a light source.

[0007]

In the measuring object imaging device according to the present invention, the optical path branching optical system is arranged toward the measuring object irradiated with the light having the narrow wavelength band from the light source, and the incident light is branched. One of the lights branched by the optical path branching optical system transmits only the light of the same wavelength as the light source light.
Is incident on the optical filter. Then, the first imaging means receives the light that has passed through the first optical filter,
An image including the measurement target, that is, an image of the measurement target by the light source light and a disturbance light image by light having the same wavelength as the light source light of the light from the disturbance light source are captured, and the image is obtained (Fig. 8).

On the other hand, the other light branched by the optical path branching optical system is incident on a second optical filter which does not transmit light having the same wavelength as the light source light but transmits light having a different wavelength from the light source light. Then, the light that has passed through the second optical filter is received by the second image pickup means, and a disturbance light image of light having a wavelength different from the light source light of the light from the disturbance light source is the first image pickup means. The images are picked up in synchronization and the image is obtained (see FIG. 9).

Both the images obtained by the first and second image pickup means are given to the image processing apparatus as image signals. In this case, even when the position of the disturbance light source changes relative to the image pickup system, both the image obtained by the first image pickup means and the image obtained by the second image pickup means are displayed. Then, the positional relationship between the image of the measurement object and the disturbance light image by the disturbance light source corresponds to each other without deviation. Therefore, the image processing device compares the lightness values indicating the light intensities of the pixels at the same address (position) in both images, and the disturbance light component of the image obtained by the first image pickup means based on the comparison result. Even if the imaging system and the disturbance light source change in position relative to each other, it is possible to obtain a clear measurement object image by the light source light with the disturbance light component removed.

[0010]

Embodiments of the present invention will be described below.
FIG. 1 is a perspective view showing the overall configuration of a measuring object imaging device mounted on a moving carriage according to a first embodiment of the present invention,
FIG. 2 is a diagram showing the overall configuration of a measurement object imaging device mounted on a moving carriage according to a second embodiment of the present invention, FIG.
FIG. 3 is a configuration explanatory view of an image pickup unit and an image processing device according to the measurement object image pickup device of the present invention.

First, the present invention is carried out in the optical three-dimensional shape measurement of the shape along the rail of a railroad peripheral structure such as a tunnel, a bridge, and a station building in a railway by using a light cutting method. An example when applied to three-dimensional shape measurement will be described. In FIG.
Reference numeral 1 denotes a moving carriage that travels on rails (tracks) RR and RL. In this embodiment, the moving carriage 1 is towed in a direction indicated by a white arrow in the figure by a towing vehicle (not shown). . On the moving carriage 1 is a light source that irradiates light in a narrow wavelength band as the wavelength characteristic as shown in FIG. 4, and is a flat plate laser light source light S that radially spreads toward the wall surface of the tunnel T whose shape is to be measured. A He-Cd laser light source 2 (hereinafter, simply referred to as a laser light source) for irradiating the laser light is arranged.

Reference numeral 3A is an image pickup system which will be described later and is arranged on the movable carriage 1 for picking up an image of the laser light source S emitted from the laser light source 2 toward the optical cutting line generated on the tunnel wall surface. It is a unit. Further, on the movable carriage 1, an image obtained by the image pickup unit 3A is processed, and in this embodiment, an image processing device 4 to be described later for creating an optical cutting line image as a measurement target image by the laser light source S. With this image processing device 4, the moving carriage 1
A computer that sequentially calculates the three-dimensional coordinates of the wall surface of the tunnel T according to the traveling of the moving carriage 1 and calculates the three-dimensional shape of the tunnel wall surface based on the optical cutting line images that are sequentially and continuously created according to the traveling of 5 and are arranged. The measuring object imaging device according to this embodiment includes a laser light source 2 and an imaging unit 3A.
And the image processing device 4.

Further, L is a lamp disturbance light source provided on the wall surface of the tunnel T for maintenance and inspection, and this lamp disturbance light source L having a broadband wavelength characteristic as shown in FIG.
This is a disturbance when capturing an image of the light section line generated on the wall surface of the tunnel. The light from the lamp disturbance light source L is incident on the imaging unit 3A as well as the reflected light from the annular light cutting line generated on the tunnel wall surface by the laser light source light S.

As shown in FIG. 3, the image pickup unit 3A has a half mirror 7 as an optical path branching optical system for branching the incident light 6 therein, and a straight light (transmitted light) from the half mirror 7. 8S is incident, and the reflected light 8R from the first optical filter 9 and the half mirror 7 that transmits only the light of the same wavelength as the laser light source light S is incident, and the light of the same wavelength as the laser light source light S is not transmitted. A second optical filter 10 that transmits light having a different wavelength is provided. Further, the image pickup unit 3A receives the light 11S that has passed through the first optical filter 9 and receives the light 11S to take an image of the first CCD camera 12A and the second optical filter 10 as the first image pickup means.
Second light as second image pickup means for receiving the light 11R that has passed through and taking an image of the light in synchronization with the first CCD camera 12A.
It is equipped with a CCD camera 13A.

As shown in FIG. 3, the half mirror 7 is installed on the diagonal of the transparent cube at an angle of 45 degrees with respect to the rear surface and the side surface of the cube, respectively. And
The first optical filter 9 having the transmission characteristic as shown in FIG. 6 is arranged on the rear surface of the transparent cube, and the second optical filter having the transmission characteristic as shown in FIG. 7 is provided on the side surface of the transparent cube. A filter 10 is arranged.

As shown in FIG. 3, the first CCD camera 12A passes through the camera lens 12a for focusing the light 11S passing through the first optical filter 9 and the first optical filter 9. Two-dimensional CCD on which focused light 11S is imaged
The image pickup device 12b is provided, and its image signal is given to the image processing device 4. Also, the second CCD camera 13A
Is a camera lens 13a for forming an image of the light 11R that has passed through the second optical filter 10, and the second optical filter.
A two-dimensional CCD image pickup device 13b on which the light 11R passing through 10 is formed is provided, and its image signal is given to the image processing device 4.

As shown in FIG. 3, the image processing device 4 includes an image comparison processing device 4a to which image signals from the first and second CCD cameras 12A and 13A are input, and an image comparison processing device 4a.
And an image memory 4b in which the image signal processed and created by is temporarily stored.

Next, the operation of the measuring object image pickup device configured as described above will be described. Figure 8 shows the first CCD camera
12A is a schematic diagram of the image obtained by 12A, FIG.
FIG. 10 is a diagram schematically showing an image obtained by the CCD camera 13A of FIG. 10, and FIG. 10 is a diagram schematically showing an image created by the image processing device 4.

The light 6 incident on the half mirror 7 of the image pickup unit 3A arranged toward the light cutting line generated on the wall surface of the tunnel T by the laser light source S emitted from the laser light source 2 is reflected by the half mirror 7. It is split (split) into two light rays, straight light 8S and reflected light 8R. Of these, the straight-traveling light 8S is guided to the first optical filter 9 that transmits only light having the same wavelength as the laser light source light S. The light 11S that has passed through the first optical filter 9 passes through the camera lens 12a and the first CCD.
An image is formed on the CCD image pickup device 12b of the camera 12A. As a result, as shown in FIG. 8, the image 14 of the light cutting line generated on the tunnel wall surface by the laser light source light S and the laser light source light S of the light from the lamp disturbance light source L are generated by the first CCD camera 12A. An image 16 in which a disturbance light image 15a of light having the same wavelength is picked up is obtained.

On the other hand, the reflected light 8R from the half mirror 7 is
Second optical filter which does not transmit light having the same wavelength as the laser light source S but transmits light having a different wavelength from the laser light source S
Guided to 10. Light that has passed through this second optical filter 10
11R is the second CCD camera via the camera lens 13a
An image is formed on the CCD image pickup device 13b of 13A. Second CC
The D camera 13A is so designed that its imaging operation is controlled in synchronization with the first CCD camera 12A, and the second CCD camera 13A controls the light from the lamp disturbance light source L as shown in FIG. An image 17 is obtained in which the disturbance light image 15b of light having a wavelength different from the laser light source S of the light is captured.

The image signals representing the both images 16 and 17 are read by the image comparison processing device 4a of the image processing device 4. The image comparison processing device 4a uses the first lightness value indicating the light intensity of the pixel at the same address in both the images 16 and 17 as the first value.
The comparison is made by subtracting the brightness value of the pixel in the image 17 obtained by the second CCD camera 13A from the brightness value of the pixel in the image 16 obtained by the CCD camera 12A. As a result of the subtraction, the brightness value of the pixel of the image 16 obtained by the first CCD camera 12A is changed to the second CCD camera 13
If it is larger than the brightness value of the image 17 obtained by A, the value of the subtraction result is stored as it is in the image memory 4b as the brightness value of the pixel at that address, and the image obtained by the second CCD camera 13A. If the brightness value is equal to or smaller than 17, the brightness value of the pixel at that address is set to zero and stored in the image memory 4b. Such comparison processing is performed on both images 16,
Do this for all pixels in 17.

The first and second CCD cameras 12A and 13
On both images 16 and 17 obtained by A respectively, the positional relationship between the image 14 of the light section line and the disturbance light images 15a and 15b correspond to each other without deviation. So in this way,
The brightness values of the pixels at the same address in both images 16 and 17 obtained by the first and second CCD cameras 12A and 13A are compared, and the first CCD camera 12 is based on the comparison result.
For image 16 obtained by A, the second CCD camera
The image pickup unit 3A and the lamp disturbance light source L are relatively positioned by performing a process of leaving only the pixels having a lightness value larger than that of the image 17 obtained by 13A and setting the lightness values of other pixels to zero. Even if there is a change, as shown in FIG. 10, the disturbance light images 15a, 15a by the lamp disturbance light source L are generated.
It is possible to obtain a clear light-section line image 18 by the laser light source S from which b is removed. The computer 5 reads out the image signal of the optical cutting line image 18 created in this way from the image memory 4b, and according to the traveling of the moving carriage 1, from the position coordinates of the optical cutting line to the tertiary of the wall surface of the tunnel T. The original coordinates are sequentially calculated, and the three-dimensional shape of the tunnel wall surface is obtained.

Next, as a second embodiment of the present invention, a case where the measuring object imaging device according to the present invention is applied to the shape measurement of the measuring object based on the image of the image of the measuring object will be described with reference to FIG. This will be described with reference to FIGS. 11 to 13.
The image pickup unit and the image processing apparatus are shown in FIG.
The same reference numerals are given and the description thereof will be omitted.

In FIG. 2, 2'is arranged above the measuring object O whose shape is to be measured based on the image of the image, and the laser source light S'as a backlight is applied to the rectangular measuring object O. It is a He-Cd laser light source for irradiation (hereinafter, simply referred to as a laser light source). The laser light source 2'is a light source for irradiating light in a narrow wavelength band as the wavelength characteristic as shown in FIG. 4, and irradiates light over a wide range with a circular cross section through a beam expander (not shown). It is the one. An image pickup unit 3A, an image processing device 4 and a computer 5 are arranged on the moving carriage 1 '.
L'is a lamp disturbance light source.

Next, the operation will be described with reference to FIGS. 2, 3 and 11 to 13. The light incident on the half mirror 7 of the image pickup unit 3A arranged toward the object to be measured O will be described below. The half mirror 7 splits the light into two rays of straight light 8S and reflected light 8R. Of these, the straight-traveling light 8S is guided to the first optical filter 9 that transmits only light having the same wavelength as the laser light source light S ′. The light 11S that has passed through the first optical filter 9 is imaged on the CCD image pickup device 12b of the first CCD camera 12A via the camera lens 12a. As a result, as shown in FIG. 11, the first CCD camera 12A blocks a part of the direct light from the laser source light S ′ by the measurement object O and the measurement object image 14 ′ and the lamp disturbance light source. An image 16 'is obtained in which the disturbance light image 15a' formed by the light having the same wavelength as the laser light source light S'of the light emitted from L'and reflected by the measurement object O is captured.

On the other hand, the reflected light 8R from the half mirror 7 is
The light is guided to the second optical filter 10 which does not transmit the light having the same wavelength as the laser light source light S ′ but transmits the light having a different wavelength from the laser light source light S ′. The light 11R having passed through the second optical filter 10 is imaged on the CCD image pickup device 13b of the second CCD camera 13A via the camera lens 13a. The imaging operation of the second CCD camera 13A is controlled in synchronization with the first CCD camera 12A. As a result, as shown in FIG. 12, the second CCD camera 13A emits light having a wavelength different from that of the laser light source light S'of the light emitted from the lamp disturbance light source L'and reflected by the measuring object O. An image 17 'obtained by picking up the disturbance light image 15b' is obtained.

Then, the first and second CCD cameras 12A
, 13A respectively, both images 16 ', 17'
Above, the shadow image 14 'of the measurement object and the ambient light images 15a', 15 '
Since the positional relationship with b'corresponds without deviation, both images obtained by the first and second CCD cameras 12A and 13A by the image processing device 4 are obtained in the same manner as in the first embodiment. The brightness values of pixels at the same address in the images 16 'and 17' are compared, and the first CC is compared based on the comparison result.
With respect to the image 16 'obtained by the D camera 12A, a process is performed in which only the pixels having a larger lightness value than the pixels of the image 17' obtained by the second CCD camera 13A are left and the lightness values of other pixels are made zero. To do. As a result, even when the image pickup unit 3A and the lamp disturbance light source L'change in position relative to each other, as shown in FIG. 13, the disturbance light images 15a 'and 15b' by the lamp disturbance light source L'are generated. It is possible to obtain a clear image 18 'of the shadow image of the measuring object by the laser light source S'that has been removed. In addition, the computer 5 calculates, based on the image signal of the image 18 ′ of the measurement object shadow image created in this way,
The shape of the measuring object O is calculated.

Next, another configuration example of the image pickup unit according to the present invention will be described. For simplification of description, the same or corresponding parts as those in FIG. 3 are designated by the same reference numerals as those in FIG. 3, and the description thereof will be omitted. Only different points will be described.

FIG. 14 is a structural explanatory view showing another example of the image pickup unit of the measuring object image pickup apparatus according to the present invention.
As shown in the figure, the image pickup unit 3C guides the incident light 6 to the half mirror 7 by one camera lens 20 arranged at the tip end, and further divides (splits) the light by the half mirror 7. The straight light 8S is guided to the first optical filter 9, and the light 11S that has passed through the first optical filter 9 is imaged on the CCD image sensor 12b, while the reflected light 8R from the half mirror 7 is converted into the second optical filter 9. The light 11R which is guided to the filter 10 and which has passed through the second optical filter 10 is transferred to the other CCD image pickup device 13
It is configured as a single imaging camera configured to form an image on b. You may make it use the imaging unit comprised in this way.

FIG. 15 is a structural explanatory view showing still another example of the image pickup unit of the measuring object image pickup apparatus according to the present invention. As shown in the figure, the image pickup unit 3B has a first CC including a half mirror 7, a camera lens 12a and a CCD image pickup device 12b, and a first optical filter 9.
D camera 12B, camera lens 13a and CCD image sensor
A second optical filter 10 including a second optical filter 10 together with 13b.
And a CCD camera 13B. You may make it use the imaging unit comprised in this way.
Further, the image pickup unit may be a so-called three-plate color CCD camera. 2 and 10 and 11 show an example in which a half mirror is used as the optical path branching optical system for branching the incident light. For example, when the light source light is weak, most of the light source light is used. It is also possible to use a wavelength-selective dichroic mirror that can utilize optical power.

[0031]

As described above, in the measuring object imaging device according to the present invention, the light path branching optical system in which the light having a narrow wavelength band is irradiated from the light source to the measuring object and is arranged toward the measuring object. The light incident on is branched by this optical path branching optical system, and one of the branched lights is guided to a first optical filter that transmits only light having the same wavelength as the light source light,
An image including the measurement target by receiving the light that has passed through the first optical filter by the first imaging unit, that is, a light source light of the image of the measurement target by the light source light and the light from the disturbance light source. While a disturbance light image of light having the same wavelength is captured, the other branched light is guided to a second optical filter that transmits light having a wavelength different from that of the light source light, and second imaging means. Thus, the light having passed through the second optical filter is received, and the disturbance light image of the light from the disturbance light source having a wavelength different from the light source light is captured in synchronization with the first imaging means. Is configured. Therefore,
Even in the case where the position of the image pickup system and that of the disturbance light source change relative to each other, on both images obtained by the first and second image pickup means, the image of the object to be measured and the disturbance light from the disturbance light source are detected. The positional relationship with the image corresponds without any shift, and the image processing device compares the brightness values of the pixels at the same address in the both images, and obtains the first imaging means based on the comparison result. By removing the disturbance light component of the image, it is possible to obtain a clear image of the object to be measured by the light source light from which the disturbance light component has been removed. Thus, according to the present invention, for example, a three-dimensional shape is measured by the optical cutting method while moving the shape of the side of a railroad peripheral structure such as a tunnel, bridge, or station building in a railroad along a rail with a moving carriage. In doing so, it is possible to provide a measurement object imaging device that can exert a remarkable effect in improving the measurement accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view showing an overall configuration of a measurement object imaging device mounted on a moving carriage according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an overall configuration of a measurement object imaging device mounted on a moving carriage according to a second embodiment of the present invention.

FIG. 3 is a configuration explanatory diagram of an image pickup unit and an image processing apparatus according to the measurement target image pickup apparatus according to the present invention.

FIG. 4 is a schematic diagram illustrating a He- relating to a measuring object imaging device according to the present invention.
It is a figure which shows the wavelength characteristic of the light irradiated from the Cd laser light source.

FIG. 5 is a diagram showing wavelength characteristics of light emitted from a lamp disturbance light source in the first and second embodiments of the present invention.

FIG. 6 is a first diagram of a measurement object imaging device according to the present invention.
It is a figure which shows the transmission characteristic of the optical filter of FIG.

FIG. 7 shows a second embodiment of the measuring object imaging device according to the present invention.
It is a figure which shows the transmission characteristic of the optical filter of.

FIG. 8 is a diagram schematically showing an image obtained by the first CCD camera in the first embodiment of the present invention.

FIG. 9 is a diagram schematically showing an image obtained by the second CCD camera in the first embodiment of the present invention.

FIG. 10 is a diagram schematically showing an image created by the image processing apparatus in the first embodiment of the present invention.

FIG. 11 shows a first CCD in the second embodiment of the present invention.
It is a figure which shows the image obtained by a camera typically.

FIG. 12 shows a second CCD in the second embodiment of the present invention.
It is a figure which shows the image obtained by a camera typically.

FIG. 13 is a diagram schematically showing an image created by the image processing apparatus in the second embodiment of the present invention.

FIG. 14 is a structural explanatory view showing another example of the imaging unit of the measurement object imaging device according to the present invention.

FIG. 15 is a structural explanatory view showing still another example of the image pickup unit of the measurement object image pickup apparatus according to the present invention.

FIG. 16 is a diagram related to a conventional technique and is an explanatory diagram of the basic principle of extraction of a light section line.

[Explanation of symbols]

1, 1 '... Mobile dolly 2, 2' ... He-Cd laser light source 3
A, 3B, 3C ... Imaging unit 4 ... Image processing device 4a ... Image comparison processing device 4b ... Image memory 5 ... Computer 7 ... Half mirror 9 ... First optical filter 10 ... Second
Optical filters 12A, 12B ... First CCD camera 12
b, 13b ... CCD image pickup device 13A, 13B ... second CCD
Camera RR, RL ... Rail T ... Tunnel O ... Measurement object S, S '... Laser light source light L, L' ... Lamp disturbance light source

Front page continuation (72) Inventor Yamaguchi, 1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture Kobe Steel Co., Ltd. Kobe Research Institute (72) Inventor Yuichiro Goto 1 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture 5-5-5 Kobe Steel Co., Ltd., Kobe Research Institute (72) Inventor Yasuharu Kami 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo Prefecture Kobe Steel Co., Ltd. (72) Inventor Yoshimoto Nishimoto 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo Prefecture Kobe Steel Works, Ltd. Kobe Research Institute

Claims (1)

[Claims] 1. A light source for irradiating a measurement target with light in a narrow wavelength band, an optical path branching optical system for branching incident light to the measurement target, and a branching by this optical path branching optical system. One of the light beams having the same wavelength as that of the light source light, and the other optical beam having the same wavelength as that of the light source light, and the other light branched by the optical path branching optical system are incident. A second optical filter that does not transmit light and transmits light having a wavelength different from that of the light source, and a first imaging unit that receives light that has passed through the first optical filter and captures an image including a measurement target. A second image pickup means for picking up an ambient light image of the light that has passed through the second optical filter in synchronization with the first image pickup means, and both of the two obtained by the first and second image pickup means. Compare the brightness values of pixels at the same address in the image And an image processing device for removing an ambient light component of the image obtained by the first image pickup means based on the comparison result to create a measurement object image by the light source light. A measuring object image pickup device.