JP2017020876A - Shape measurement device and shape measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shape measurement device and shape measurement method that enable an easy execution and inexpensive generation of a light cut-out image having an excellent signal-to-noise ratio even under a condition where disturbance light causes problems.SOLUTION: A shape measurement device according to the present invention includes: a measurement device that includes a laser light source radiating linear laser light with respect to a surface of a measured work reflecting or radiating light, and an imaging device photographing a light cutting line by the laser light on the surface of the measured work to generate a light cutting image; and a computation processing device that executes image processing with respect to the light cutting image generated by the measurement device, and calculates a shape of the measured work. The imaging device includes: an image side telecentric lens that focuses an image of the light cutting line onto an image pick-up element; and an optical band-pass filter that is disposed between the image side telecentric lens and the image pick-up element and has a prescribed band width.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a shape measuring device and a shape measuring method.

  Shape measurement technology that measures the surface shape of the object to be measured based on the so-called light cutting method by imaging the linear light irradiated on the surface of the object to be measured is not only in the steel industry but also in various fields. Widely used. For example, the following Patent Document 1 discloses a shape measuring device by a light cutting method using a linear laser beam and a delay integration camera, and the following Patent Document 2 discloses a linear laser beam. And a shape measuring apparatus using an optical cutting method using an area camera.

  When applying such light-cutting shape measurement technology to red-hot objects such as slabs, which are semi-finished steel products, the self-luminescence mainly distributed in the red wavelength band is the signal-to-noise ratio. This is a problem in terms of (Signal-Noise ratio). In addition, when the shape measuring technique based on the light cutting method as described above is used outdoors, sunlight becomes a problem in terms of the SN ratio. In such a case, as a countermeasure against disturbance light, select a light source whose wavelength band does not overlap with disturbance light, such as a blue light source for a red-hot object, or use a narrow-band light source such as a laser and use an interference filter. Only the wavelength of the light source is selectively transmitted.

  When selecting the wavelength of the light source, the problem is that the camera sensitivity generally decreases with a blue light source, and if the disturbance light spectrum is wide, such as sunlight, the disturbance light and the wavelength band do not overlap. There is a problem that the light source cannot be found. For this reason, it is easier to use an optical bandpass filter (so-called interference filter) as a countermeasure against disturbance light that can be applied regardless of the wavelength of disturbance light.

  Here, when an interference filter is used, a narrow-band interference filter is often used in order to improve the wavelength selectivity of the optical cutting line. However, when light is incident obliquely on the interference filter, a shift occurs in the light transmission band. , There is a problem that the optical cutting line becomes invisible around the visual field. In this case, the signal-to-noise ratio of the obtained light section image is lowered, which leads to a decrease in accuracy of the shape measurement result. The problem of visual field due to such oblique incidence is that there is a limit to where the shape measuring device can be installed, such as various lines in the steel industry, and the distance to the measurement object is as short as possible (ie This is remarkable in a situation where a wide-angle lens must be used to reduce the size of the shape measuring apparatus.

  In order to cope with the above-described problem of transmission band shift due to oblique incidence, the following Patent Document 3 proposes a method using a spherical interference filter, and the following Patent Document 4 differs depending on the location. A method using an interference filter having transmission characteristics has been proposed.

Japanese Patent Laid-Open No. 2004-3930 JP 2010-71722 A JP 2012-173277 A JP 2012-242134 A

  However, the interference filters disclosed in Patent Document 3 and Patent Document 4 are not general-purpose, and there is a problem that it is difficult and expensive to manufacture such an interference filter. For this reason, there has been a demand for an easy-to-implement and inexpensive technique capable of generating a light-cut image having a good signal-to-noise ratio even under circumstances where disturbance light is a problem.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide an optical cutting device having a good signal-to-noise ratio even under circumstances where disturbance light is a problem. It is an object of the present invention to provide a shape measuring apparatus and a shape measuring method capable of generating an image easily and inexpensively.

  In order to solve the above-described problem, according to an aspect of the present invention, a laser light source that irradiates a surface of a measurement object that reflects or emits light with a linear laser beam, and the measurement object An imaging device that captures an optical cutting line by the laser beam on the surface of the image and generates an optical cutting image, and performs image processing on the optical cutting image generated by the measuring device And an arithmetic processing unit that calculates the shape of the object to be measured, wherein the imaging device includes an image-side telecentric lens that forms an image of the optical cutting line on an imaging device, and the image-side telecentric lens. And an optical band-pass filter having a predetermined bandwidth disposed between the image sensor and the image sensor.

  The laser power density of the linear laser beam and the bandwidth of the optical bandpass filter are the illuminance on the imaging surface required for imaging the optical cutting line, and the object to be measured is reflected or emitted. Preferably, it is determined based on the signal-to-noise ratio required for the ambient light that is the light.

  The numerical aperture according to the bandwidth of the optical bandpass filter is preferably set smaller than the numerical aperture determined by the F value of the imaging device.

  The laser power density at the surface of the object to be measured is a disturbance in a plane coordinate system in which the vertical axis represents the laser power density of the linear laser beam and the horizontal axis represents the bandwidth of the optical bandpass filter. The curve representing the relationship between the laser power density and the bandwidth with a constant signal-to-noise ratio with respect to the light, and the relationship between the laser power density and the bandwidth with a constant brightness of the image of the light section line on the image plane. It is preferably set to a value equal to or higher than the laser power density corresponding to the intersection of the curve to be represented.

  The curve representing the relationship between the laser power density and the bandwidth at which the signal-to-noise ratio with respect to the disturbance light is constant may be a straight line.

  The bandwidth of the optical bandpass filter is preferably 5 nm or more and 10 nm or less.

  In order to solve the above-described problem, according to another aspect of the present invention, a laser light source that irradiates a surface of the object to be measured with a linear laser beam, and the surface of the object to be measured. An image-side telecentric lens for imaging a light-cutting line by laser light to generate a light-cutting image, and forming an image of the light-cutting line on an image pickup device, the image-side telecentric lens, and the image pickup device Generating a light-cutting image relating to an object to be measured that reflects or emits light by a measuring device including an imaging device having an optical bandpass filter having a predetermined bandwidth disposed between And a step of calculating the shape of the object to be measured by performing image processing on the light section image generated by the measuring device.

  As described above, according to the present invention, by using an image-side telecentric lens that is easy to implement and inexpensive, and an optical bandpass filter having a predetermined bandwidth provided at the subsequent stage of the image-side telecentric lens, Even under circumstances where ambient light becomes a problem, it is possible to generate a light-cut image having a good signal-to-noise ratio.

It is the block diagram which showed an example of the structure of the shape measuring apparatus which concerns on embodiment of this invention. It is explanatory drawing which showed typically an example of the structure of the measuring apparatus which concerns on the same embodiment. It is explanatory drawing for demonstrating an optical band pass filter. It is explanatory drawing for demonstrating an optical band pass filter. It is explanatory drawing which showed typically an example of the structure of the imaging device which concerns on the embodiment. It is the graph which showed the relationship between the divergence angle of a light ray, and the amount of wavelength shifts. It is explanatory drawing which showed typically the relationship between a laser power density and a bandwidth. It is explanatory drawing which showed typically the relationship between a laser power density and a bandwidth. It is explanatory drawing which showed typically the relationship between a laser power density and a bandwidth. It is the block diagram which showed an example of the structure of the image process part with which the arithmetic processing apparatus which concerns on the same embodiment is provided. It is the flowchart which showed an example of the flow of the determination method of the laser power density and bandwidth which concerns on the embodiment. It is the flowchart which showed an example of the flow of the shape measuring method which concerns on the embodiment. It is the block diagram which showed an example of the hardware constitutions of the arithmetic processing unit which concerns on the same embodiment. FIG. 3 is an explanatory diagram for explaining Example 1; FIG. 10 is an explanatory diagram for explaining Example 2; FIG. 10 is an explanatory diagram for explaining Example 2; FIG. 10 is an explanatory diagram for explaining Example 2; FIG. 10 is an explanatory diagram for explaining Example 2; FIG. 10 is an explanatory diagram for explaining Example 2;

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

(About shape measuring device)
Hereinafter, the shape measuring apparatus according to the first embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 1 is a block diagram showing an example of the configuration of the shape measuring apparatus according to the present embodiment. FIG. 2 is an explanatory diagram schematically showing an example of the configuration of the measuring apparatus according to the present embodiment. 3A and 3B are explanatory diagrams for describing the optical bandpass filter. FIG. 4 is an explanatory diagram schematically illustrating an example of the configuration of the imaging apparatus according to the present embodiment. FIG. 5 is a graph showing the relationship between the light spread angle and the wavelength shift amount. 6A and 6B are explanatory diagrams schematically showing the relationship between the laser power density and the bandwidth. FIG. 7 is an explanatory diagram schematically showing the relationship between the laser power density and the bandwidth. FIG. 8 is a block diagram illustrating an example of a configuration of an image processing unit included in the arithmetic processing device according to the present embodiment.

<Overall configuration of shape measuring device>
The shape measuring device according to the present embodiment is a device that measures the shape of the surface of a measurement object that reflects or emits light using a so-called light cutting method.
Here, the object to be measured, which is the object to be measured by the shape measuring apparatus according to the present embodiment and that reflects or emits light, is not particularly limited, and examples thereof include various metals that are red hot. As such, it may be one that emits light of a predetermined wavelength, or a metal that is installed outdoors and reflects sunlight on its own surface.

  Such a shape measuring apparatus 1 mainly includes a measuring apparatus 10 and an arithmetic processing unit 20 as schematically shown in FIG.

  The measurement apparatus 10 irradiates the measurement object S with linear laser light, and captures a light cutting line by the linear laser light on the surface of the measurement object S, thereby relating to the measurement object S. An apparatus for generating a light section image. In the shape measuring apparatus 1 according to the present embodiment, an object that reflects or emits light of a predetermined wavelength is the measurement object S. Therefore, the measurement apparatus 10 includes a light cutting line on the surface of the measurement object S. Not only the image but also the light reflected or radiated from the measuring object S enters as disturbance light.

  As schematically shown in FIG. 2, the measurement apparatus 10 images a laser light source 11 that irradiates the measurement target S with linear laser light and a light cutting line on the surface of the measurement target S. The imaging device 13 is configured to be configured.

  The laser light source 11 includes, for example, a light source unit that emits laser light having a predetermined wavelength such as a visible light band, and a laser beam emitted from the light source unit that is condensed in the line width direction while spreading in the length direction. And a lens (for example, a cylindrical lens, a rod lens, a Powell lens, etc.) for making a shaped light.

  The imaging device 13 has a lens having a specific optical system as will be described later, and a CCD (Charge Coupled Device) or CMOS (Complementary) on which an image of a light cutting line of the measurement object S is formed. An imaging device such as a metal oxide semiconductor) and an optical system band-pass filter as described later.

  The positional relationship between the laser light source 11 and the imaging device 13 is not particularly limited, but as schematically shown in FIG. 2, the optical axis of the imaging device 13 and the measurement object S The imaging device 13 is preferably provided so that the normal direction of the surface is substantially parallel. In addition, the laser light source 11 is preferably provided in an oblique direction with respect to the surface of the measurement object S so that the optical axis of the laser light source 11 and the optical axis of the imaging device 13 form a predetermined angle.

  The detailed configuration of the imaging device 13 will be described later again.

  The measuring apparatus 10 performs a linear laser light irradiation process, an optical cutting line imaging process, and the like at predetermined time intervals under the control of the arithmetic processing unit 20 to be described later, and thereby a plurality of light cut images. Is generated, the obtained light section image is output to the arithmetic processing unit 20.

  The arithmetic processing device 20 acquires the light section image generated by the measurement device 10 and performs a known process as disclosed in Patent Document 1 and Patent Document 2 on the acquired light section image. Thus, a luminance image and a concavo-convex image are generated. Thereafter, the arithmetic processing device 20 generates information representing the surface shape of the measurement object S by performing predetermined image processing on the generated luminance image and uneven image. In addition, the arithmetic processing device 20 also functions as a control unit that controls an imaging process (in other words, a light cut image generation process) in the measurement apparatus 10.

  The detailed configuration of the arithmetic processing device 20 will be described later.

<About Configuration of Imaging Device 13>
Next, the configuration of the imaging device 13 included in the measurement device 10 according to the present embodiment will be described in detail with reference to FIGS. 3A to 4.

  As previously mentioned, in the shape measuring apparatus 1, a narrow band interference filter is often used as an optical band pass filter in order to remove the influence of disturbance light. Such an interference filter is designed on the assumption that light enters perpendicularly to the surface of the interference filter.

  As shown in FIG. 3A, when light is incident on the interference filter perpendicularly, the light reflected by the upper surface (reflected wave b) is in phase because the refractive index of the interference filter is n> 1. Is inverted, and the phase of the light reflected by the lower surface (reflected wave a) does not change. Therefore, when the optical path length difference (the thickness of the interference filter is d, which is 2nd) is an integral multiple of the wavelength, the reflected light intensity is zero and the amount of light transmitted through the filter is maximum. On the other hand, as shown in FIG. 3B, consider a case where light is incident on the interference filter obliquely. In FIG. 3B, the dotted line is an equiphase line, and the optical path lengths of AC and BD are equal, so the optical path length difference is CED. The length of the CED is 2nd cos θ when the incident angle in the interference filter is θ, and the optical path length difference decreases as θ increases. Therefore, the transmission wavelength is shifted to a short wavelength. Such a short wavelength shift of the transmission wavelength due to oblique incidence becomes significant when a wide-angle lens (short focus lens) is used in order to shorten the separation distance between the imaging device 13 and the measuring object S.

Now, the condensing half angle of the interference filter as shown in FIGS. 3A and 3B (the same as the incident angle in the interference filter in FIG. 3B) is θ [degree], and the effective refractive index of the interference filter is n. and then, the center wavelength of light during normal incidence and lambda _{0 [nm],} when the center wavelength of the light when tilting the incident angle theta degrees and lambda _theta [nm], these parameters, the following formula 101 The following relationship is established.

  In order to suppress such a short wavelength shift due to oblique incidence, in the imaging device 13 according to the present embodiment, as schematically illustrated in FIG. 4, the image side telecentric is used as the lens 103 attached to the camera body 101. A lens is used. In the image side telecentric lens, as schematically shown in FIG. 4, the aperture stop is provided on the front focal plane of the optical system (in other words, on the focal plane on the object side of the optical system). In such an image side telecentric optical system, the exit pupil can be at infinity on the image side, and the principal ray in the image space is parallel to the optical axis. Such an image side telecentric lens is not particularly limited, and a known lens can be used according to the focal length f required for the lens 103.

  In the imaging device 13 according to the present embodiment, as illustrated in FIG. 4, light having a desired center wavelength is transmitted between the image side telecentric lens and the imaging element 105 provided in the camera body 101. An optical bandpass filter (interference filter) 107 having a predetermined bandwidth is provided. Since the principal ray of the light incident on the lens 103 is parallel to the optical axis by the image side telecentric lens, oblique incidence on the optical bandpass filter 107 as shown in FIG. 3 is suppressed. As a result, even when a wide-angle lens is used as the lens 103, it is possible to prevent a non-transmission portion from occurring in the image of the light section line due to the oblique incidence on the optical bandpass filter 107.

  The arrangement position of the optical bandpass filter 107 is not particularly limited as long as it is located between the optical system of the image side telecentric lens and the image sensor 105, and is provided inside the lens 103. It may be provided inside the camera body 101, or may be provided at a connection portion between the lens 103 and the camera body 101.

  The configuration of the imaging device 13 according to the present embodiment has been described in detail above.

<Restriction of bandwidth of optical bandpass filter>
Next, restrictions on the bandwidth of the optical bandpass filter 107 will be described with reference to FIG.

  In the imaging apparatus 13 as shown in FIG. 4, if the light spread angle θ seen from the image plane is small, the image of the subject on the image plane (that is, the image of the light section line) becomes dark. In the case of an optical bandpass filter, a light beam having a large divergence angle is obliquely incident and is not transmitted, which is substantially equivalent to limiting the divergence angle (that is, reducing the aperture). Therefore, the numerical aperture NA = sin θ is determined by the bandwidth of the filter. For example, when light having a wavelength of 640 nm is incident on an optical bandpass filter having an effective refractive index n = 1.5, the relationship between the wavelength shift amount and the incident angle is shown in FIG. It becomes like.

  For example, when the divergence angle θ = 10 degrees shown in FIG. 4, the numerical aperture NA of the optical bandpass filter provided in the air is sin = θ = 0.1736. On the other hand, since the relationship represented by F = 1 / (2 × NA) is established between the F value and the numerical aperture NA, the F value corresponding to the spread angle θ = 10 degrees is 1 / (2 × 0.1736) = 2.9. Now, in the graph shown in FIG. 5, it can be seen that the amount of wavelength shift corresponding to the spread angle θ = 10 degrees is 4 nm. Therefore, the optical bandpass filter as exemplified in the present example has an action equivalent to that of the F2.9 stop when the bandwidth is 4 nm. When the equivalent F value of such an optical bandpass filter is larger than the F value of the lens 103, the brightness of the obtained image is restricted by the bandwidth of the optical bandpass filter.

Since the brightness of the image is inversely proportional to the square of the F value, it is proportional to the square of the numerical aperture NA. Optical bandpass filter 107 according to this embodiment, since the central wavelength lambda ₀ of the time of normal incidence, the light to be transmitted through the wavelength to the center wavelength lambda _theta upon oblique incidence in spread angle theta is determined, the band The width is required at least by the wavelength shift amount Δλ = λ ₀ −λ _θ . Now, assuming that the bandwidth of the optical bandpass filter 107 is Δλ, the bandwidth Δλ is expressed by the following equation 103 using the above equation 101.

  Solving the above equation 103 with respect to the numerical aperture NA, the following equation 105 is obtained.

  Therefore, the relationship between the equivalent F value of the optical bandpass filter 107 and the bandwidth Δλ is expressed by the following expression 107 from F = 1 / (2 × NA).

  In the above, the restrictions regarding the bandwidth of the optical bandpass filter 107 according to the present embodiment have been described in detail.

<Restrictions on laser power density>
Next, restrictions on the laser power density of the linear laser light emitted from the laser light source 11 in the measurement apparatus 10 according to the present embodiment will be described in detail with reference to FIGS. 6A to 7.

[Restriction by SN ratio]
In order to obtain a light-cut image with a good S / N ratio, it is important to consider restrictions on the S / N ratio. Now, on the image plane of the imaging device 13 as shown in FIG. 4, the S / N ratio represented by the intensity of the light source / the intensity of disturbance light is examined.

When considering the spectrum distribution of disturbance light near the laser wavelength (the spectrum when the horizontal axis is wavelength [nm] and the vertical axis is the power density per wavelength [mW / cm ² / nm]), this spectrum If the distribution can be considered flat, the signal-to-noise ratio (SNR) is proportional to the product of the inverse of the bandwidth and the laser power density. That is, the relationship “SNR∝ (1 / bandwidth) × laser power density” is established. In this case, considering a planar coordinate system in which the vertical axis indicates the laser power density and the horizontal axis indicates the bandwidth, the relationship between the laser power density and the bandwidth at which the SN ratio is constant is represented by a straight line.

On the other hand, when the spectral distribution of disturbance light in the vicinity of the laser wavelength cannot be regarded as flat, the intensity of the disturbance light is integrated from the spectral distribution L _d (λ) of the disturbance light from the wavelength λ _θ to the wavelength λ _0. It becomes the value. If the intensity of the light source is represented as L _p , the SN ratio (SNR) at this time is a value represented by the following formula 111. In this case, considering a planar coordinate system in which the vertical axis indicates the laser power density and the horizontal axis indicates the bandwidth, the relationship between the laser power density and the bandwidth at which the SN ratio is constant is not a straight line but a curve. .

  In practice, a narrow-band optical bandpass filter having a bandwidth of about 5 to 10 nm is often used as the optical bandpass filter 107, so that the spectrum distribution of disturbance light near the laser wavelength is flat. Can often be considered.

[Brightness constraint on the image plane]
Even in the absence of ambient light, in order to capture an image with a desired exposure time and lens aperture, it is important that the image of the light section line has a certain brightness or more on the image plane. In the following, the conditions for obtaining a constant brightness when there is no ambient light will be considered.

Here, considering the brightness limitation due to the equivalent aperture effect in the optical bandpass filter 107, in the imaging device 13 as shown in FIG. 4, the image brightness on the image plane is the square of the numerical aperture. It is proportional to the product of the laser power density. That is, the relationship “image brightness on the image plane (numerical aperture ² ) × laser power density” is established. In this case, when the numerical aperture is replaced with the band width of the optical bandpass filter 107 using Equation 105, the image is obtained in a plane coordinate system in which the vertical axis represents the laser power density and the horizontal axis represents the bandwidth. The relationship between the laser power density at which the brightness is constant and the bandwidth is represented by a curve.

  Accordingly, the S / N ratio becomes a predetermined value or more and the brightness of the image on the image plane also becomes a predetermined value or more is a plane coordinate system in which the vertical axis indicates the laser power density and the horizontal axis indicates the bandwidth. In FIG. 5, the laser power density and the bandwidth at which the brightness on the image plane is constant above the curve (or straight line) L1 representing the relationship between the laser power density and the bandwidth at which the SN ratio with respect to disturbance light is constant. This is a region represented on the upper side of the curve L2 representing the relationship.

  6A and 6B schematically show this relationship. 6A corresponds to the case where the relationship between the laser power density at which the SN ratio with respect to disturbance light is constant and the bandwidth can be represented by the curve L1, and FIG. 6B is the laser power density at which the SN ratio with respect to disturbance light is constant. This corresponds to the case where the relationship between and the bandwidth can be represented by a straight line L1.

  Referring to FIGS. 6A and 6B, the laser power of the linear laser light emitted from the laser light source 11 is used in order for the SN ratio to be a predetermined value or more and the brightness of the image on the image plane to be a predetermined value or more. It can be seen that the density has a lower limit. That is, in order for the SN ratio to be equal to or greater than a predetermined value and the brightness of the image on the image plane to be equal to or greater than the predetermined value, the laser power density of the linear laser light emitted from the laser light source 11 is the curve L1 and the curve L1. It is necessary to be equal to or higher than the laser power density corresponding to the intersection with L2.

  Further, as described above, the bandwidth of the optical bandpass filter 107 needs to be equal to or smaller than the bandwidth corresponding to the F value of the lens 103. When the bandwidth of the optical bandpass filter exceeds the bandwidth corresponding to the F value of the lens 103, the light cutting line does not become bright even when the bandwidth of the optical bandpass filter 107 is widened. Only disturbance light increases.

  Therefore, in consideration of these restrictions, the SN ratio is not less than a predetermined value and the brightness of the image on the image plane is not less than the predetermined value in the plane coordinate system shown in FIGS. 6A and 6B. It can be seen that this is a region represented by diagonal lines.

  FIG. 7 is a schematic diagram showing how the required laser power density changes in accordance with the camera sensitivity of the imaging device 13. As is clear from FIG. 7, the laser power density corresponding to the intersection of the curve L2 and the straight line representing the bandwidth corresponding to the F value of the lens 103 enables imaging processing when there is no disturbance light. The minimum required brightness (laser power density). On the other hand, as described above, in order for the SN ratio to be equal to or higher than a predetermined value and the brightness of the image on the image plane to be equal to or higher than the predetermined value, the laser power density corresponding to the intersection of the curves L1 and L2 is equal to or higher. Laser power density is required.

  Therefore, when the camera sensitivity of the imaging device 13 is high, the imaging process when there is no disturbance light can be realized with a low laser power density, but when disturbance light exists, as shown in FIG. The minimum required amount of raising is larger. On the other hand, when the camera sensitivity of the imaging device 13 is low, the imaging process when there is no disturbance light has a relatively high laser power density, but the minimum amount of increase required in the presence of disturbance light is Relatively small.

  As can be seen from FIG. 7, if the laser power density is large, the bandwidth of the optical bandpass filter 107 can be narrowed.

  In the measurement apparatus 10 according to the present embodiment, the laser power density of the linear laser light emitted from the laser light source 11 and the bandwidth of the optical bandpass filter 107 are set based on the restrictions as described above. .

  Actually, the bandwidth of the optical bandpass filter 107 provided in the imaging device 13 is in accordance with the performance of the narrowband optical bandpass filter that can be used in the device (for example, bandwidth = 5 nm to 10 nm). Often set. Therefore, in the shape measuring apparatus 1 according to the present embodiment, the arithmetic processing unit 20 described later uses a laser so as to satisfy the above relationship according to the bandwidth of the optical bandpass filter 107 to be used, which is 5 nm to 10 nm. The laser power density of the linear laser light emitted from the light source 11 is controlled.

[Regarding Method for Specifying Curve L1 and Curve L2]
Next, a method for specifying the curve L1 and the curve L2 as described above will be briefly described.

First, a method for specifying the curve L1 representing the relationship between the laser power density at which the SN ratio is constant and the bandwidth will be described.
In this case, in order to specify the curve L1, first, the spectral distribution of the disturbing light of interest and the power density of the disturbing light on the measuring object S are actually measured, and the object to be measured S Specific surface characteristics (e.g., emissivity, reflectivity, etc.). In addition, a curve or a straight line representing the power density of the disturbance light in consideration of the S / N ratio obtained from the generated light section image and the surface characteristics of the measuring object S using the obtained spectrum distribution of the disturbance light. What is necessary is just to calculate L1.

  Alternatively, when the spectral distribution of the disturbance light of interest can be regarded as constant, the band width of the bandpass filter and the laser power density are fixed, the experiment is performed in the presence of disturbance light, and the plane shown in FIGS. 6A and 6B is obtained. The SN ratio of one point on the coordinates is obtained experimentally. Since the straight line passing through the origin and the point is a straight line with a constant S / N ratio, the straight line whose slope is adjusted so as to have a desired S / N ratio may be set as L1. For example, when the measured S / N ratio is 3 and the required S / N ratio is 12, the slope may be quadrupled.

  Next, a method for specifying the curve L2 representing the relationship between the laser power density at which the brightness on the image plane is constant and the bandwidth will be described.

First, in the exposure time and F value required for imaging, a laser power density is obtained through experiments or the like so that the light section line can be imaged with a desired brightness when there is no ambient light. Next, the bandwidth corresponding to the F value of the image-side telecentric lens to be used is calculated using Expression 107. Subsequently, “(numerical aperture ² ) passes through a point represented by (a minimum power density at which imaging processing can be performed in the absence of disturbance light, a bandwidth corresponding to the F value of the lens). The constant part of the curve represented by “) × Laser power density = constant” is specified by a known method. Thereby, the curve L2 can be specified.

  The flow of such a curve specifying method will be described again below, and will be described in detail with specific examples in the following examples.

  The measurement apparatus 10 included in the shape measurement apparatus 1 according to the present embodiment has been described in detail above with reference to FIGS.

<About the configuration of the arithmetic processing unit 20>
Next, returning to FIG. 1 again, the configuration of the arithmetic processing unit 20 will be described in detail.
The arithmetic processing device 20 included in the shape measuring apparatus 1 according to the present embodiment controls and controls the optical cutting line imaging process (that is, the optical cutting image generation process) in the measuring apparatus 10 and is generated by the measuring apparatus 10. This is an apparatus for calculating the shape of an object by performing image processing on the obtained light section image.

  As schematically illustrated in FIG. 1, the arithmetic processing device 20 includes, for example, an imaging control unit 21, an image processing unit 23, a display control unit 25, and a storage unit 27.

  The imaging control unit 21 is realized by a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a communication device, and the like. The imaging control unit 21 performs imaging control of the measurement object S by the measurement device 10. More specifically, when the measurement object S is installed at a predetermined position, the imaging control unit 21 has a laser power density that satisfies the conditions described above for the laser light source 11 of the measurement apparatus 10. A trigger signal for starting the irradiation of the linear laser beam being performed, and a trigger for starting the imaging processing of the captured image of the optical section line (that is, the optical section image) to the imaging device 13 Send a signal.

  The image processing unit 23 is realized by, for example, a CPU, a ROM, a RAM, a communication device, and the like. The image processing unit 23 performs various types of image processing using the light section image acquired from the imaging device 13 of the measurement device 10.

  More specifically, the image processing unit 23 generates a concavo-convex image and a luminance image as disclosed in Patent Document 1 and Patent Document 2 using the light cut image output from the measurement apparatus 10. . Thereafter, the image processing unit 23 calculates the surface shape of the measurement object S using the generated uneven image and luminance image.

  When the image processing unit 23 finishes the shape measurement process on the surface of the measurement object S, the image processing unit 23 transmits information about the obtained measurement result to the display control unit 25.

  The display control unit 25 is realized by, for example, a CPU, a ROM, a RAM, an output device, and the like. The display control unit 25 transmits the measurement result of the measurement object S transmitted from the image processing unit 23 to an output device such as a display provided in the arithmetic processing device 20 or an output device provided outside the arithmetic processing device 20. Perform display control when displaying. Thereby, the user of the shape measuring apparatus 1 can grasp various measurement results related to the surface shape of the measuring object S on the spot.

  The storage unit 27 is realized by, for example, a RAM or a storage device included in the arithmetic processing device 20 according to the present embodiment. The storage unit 27 stores various parameters, intermediate progress of processing, and various databases and programs that need to be saved when the arithmetic processing unit 20 according to the present embodiment performs some processing. To be recorded. The storage unit 27 can be freely read / written by the imaging control unit 21, the image processing unit 23, the display control unit 25, and the like.

[Configuration of Image Processing Unit 23]
Next, the configuration of the image processing unit 23 included in the arithmetic processing device 20 according to the present embodiment will be briefly described with reference to FIG.

  As shown in FIG. 8, the image processing unit 23 according to the present embodiment mainly includes a data acquisition unit 201, a shape calculation unit 203, and a result output unit 205.

  The data acquisition unit 201 is realized by, for example, a CPU, a ROM, a RAM, a communication device, and the like. The data acquisition unit 201 acquires image data of the light section image generated by the measurement device 10 from the measurement device 10. The data acquisition unit 201 outputs the acquired image data of the light section image to the shape calculation unit 203 described later.

  The shape calculation unit 203 according to the present embodiment is realized by a CPU, a ROM, a RAM, and the like, for example. The shape calculation unit 203 calculates the surface shape of the measuring object S using the light section image generated using the light section line.

  More specifically, the shape calculation unit 203 uses the light section image generated by using the light section line to generate a concavo-convex image and a luminance image as disclosed in Patent Document 1 and Patent Document 2 above. Generate. Thereafter, the shape calculation unit 203 calculates the surface shape of the measurement object S using the generated uneven image and luminance image.

  Here, the method by which the shape calculation unit 203 calculates the surface shape of the measurement object S is not particularly limited, and a known method based on the light cutting method can be appropriately used.

  Information representing the result of the shape calculation process performed by the shape calculation unit 203 is output to the result output unit 205.

  The result output unit 205 is realized by, for example, a CPU, a ROM, a RAM, and the like. The result output unit 205 outputs information related to the shape calculation result output from the shape calculation unit 203 to the display control unit 25. As a result, various types of information as described above are output to a display unit (not shown). In addition, the result output unit 205 may output the obtained result to an external device such as a manufacturing control process computer, or may create various forms using the obtained result. Further, the result output unit 205 may store various information as described above as history information in the storage unit 27 or the like in association with time information related to the date and time when the information is calculated.

  Heretofore, an example of the function of the arithmetic processing device 20 according to the present embodiment has been shown. Each component described above may be configured using a general-purpose member or circuit, or may be configured by hardware specialized for the function of each component. In addition, the CPU or the like may perform all functions of each component. Therefore, it is possible to appropriately change the configuration to be used according to the technical level at the time of carrying out the present embodiment.

  A computer program for realizing each function of the arithmetic processing apparatus according to the present embodiment as described above can be produced and installed in a personal computer or the like. In addition, a computer-readable recording medium storing such a computer program can be provided. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, or the like. Further, the above computer program may be distributed via a network, for example, without using a recording medium.

(About laser power density and bandwidth setting method)
Next, the flow of the laser power density and bandwidth setting method in the shape measuring apparatus 1 according to the present embodiment will be briefly described with reference to FIG.

  In the setting method of the laser power density and the bandwidth, first, using the knowledge about the power density of the disturbance light obtained by measuring the spectrum distribution of the disturbance light and the power density of the disturbance light on the measurement object S, A curve (or straight line) L1 relating to the S / N ratio is calculated in consideration of surface characteristics such as emissivity and reflectance of the measuring object S and the S / N ratio obtained from the light-cut image (step S101).

  Alternatively, when the spectral distribution of the disturbance light of interest can be regarded as constant, the band width of the bandpass filter and the laser power density are fixed, the experiment is performed in the presence of disturbance light, and the plane shown in FIGS. 6A and 6B is obtained. An SN ratio of one point on the coordinates is experimentally obtained, and a straight line connecting the origin and the point is drawn to obtain a straight line having a constant SN ratio. Next, the ratio K between the measured S / N ratio and the necessary S / N ratio is obtained, and the slope of the straight line having the constant S / N ratio is multiplied by K to calculate the straight line L1. (Step S101).

  Next, a laser power density that can capture an image of the light cutting line with a desired brightness when there is no disturbance light is specified by an experiment or the like. (Step S103)

  Subsequently, based on the F value of the image side telecentric lens used as the imaging device 13, the bandwidth corresponding to the F value is expressed by the relationship of F = 1 / (2 × NA) and the above equation 105. Based on the calculation (step S105).

  Subsequently, in the plane coordinate system as shown in FIGS. 6A to 7, a point at which the power density value necessary for the imaging process obtained in step S <b> 103 is obtained at the position of the bandwidth corresponding to the F value of the lens is passed. The curve L2 to be calculated is calculated (step S107).

  In addition, the laser power density and the bandwidth are determined from the regions determined by the obtained curves L1 and L2 and the bandwidth corresponding to the F value of the lens (the regions represented by hatching in FIGS. 6A and 6B). A combination is selected (step S109).

  By performing the processing in the flow as described above, the laser power density and the bandwidth in the shape measuring apparatus 1 according to the present embodiment can be set. This setting method will be specifically described below with reference to examples.

(About shape measurement method)
Next, the flow of the shape measuring method performed by the shape measuring apparatus 1 according to the present embodiment will be briefly described with reference to FIG.

  In the shape measuring method according to the present embodiment, first, a laser is applied to a measuring device 10 using an imaging device 13 having an image-side telecentric lens and an optical bandpass filter provided between the lens and the imaging device. The laser power density of the light source 11 and the bandwidth of the optical bandpass filter are set (step S151). The method for setting the laser power density and the bandwidth is as described with reference to FIG.

  Next, the imaging control unit 21 of the arithmetic processing unit 20 is used by using the imaging device 13 having the image side telecentric lens as described above and provided with an optical bandpass filter having a bandwidth set in the subsequent stage. Under this control, an optical cutting line having a predetermined laser power density is imaged (step S153). Thereby, a light section image of the measuring object S is generated. The generated light section image is output from the imaging device 13 to the arithmetic processing device 20.

  The image processing unit 23 of the arithmetic processing device 20 performs image processing on the generated light section image, and generates a concavo-convex image and a luminance image as a shape calculation image (step S155). Thereafter, the image processing unit 23 calculates the surface shape of the measurement object S based on the generated shape calculation images (step S157). Subsequently, the image processing unit 23 of the arithmetic processing device 20 outputs the obtained result (step S159).

  Thereby, the user of the shape measuring apparatus 1 according to the present embodiment can grasp the measurement result related to the surface shape of the measuring object S on the spot.

  The example of the flow of the shape measuring method according to the present embodiment has been briefly described above with reference to FIG.

(About hardware configuration)
Next, a hardware configuration of the arithmetic processing device 20 according to the embodiment of the present invention will be described in detail with reference to FIG. FIG. 11 is a block diagram for explaining a hardware configuration of the arithmetic processing unit 20 according to the embodiment of the present invention.

  The arithmetic processing unit 20 mainly includes a CPU 901, a ROM 903, and a RAM 905. The arithmetic processing device 20 further includes a bus 907, an input device 909, an output device 911, a storage device 913, a drive 915, a connection port 917, and a communication device 919.

  The CPU 901 functions as an arithmetic processing device and a control device, and controls all or part of the operation in the arithmetic processing device 20 according to various programs recorded in the ROM 903, the RAM 905, the storage device 913, or the removable recording medium 921. The ROM 903 stores programs used by the CPU 901, calculation parameters, and the like. The RAM 905 primarily stores programs used by the CPU 901, parameters that change as appropriate during execution of the programs, and the like. These are connected to each other by a bus 907 constituted by an internal bus such as a CPU bus.

  The bus 907 is connected to an external bus such as a PCI (Peripheral Component Interconnect / Interface) bus via a bridge.

  The input device 909 is an operation unit operated by the user, such as a mouse, a keyboard, a touch panel, a button, a switch, and a lever. The input device 909 may be, for example, remote control means (so-called remote control) using infrared rays or other radio waves, or may be an external connection device 923 such as a PDA corresponding to the operation of the arithmetic processing device 20. May be. Furthermore, the input device 909 includes, for example, an input control circuit that generates an input signal based on information input by a user using the operation unit and outputs the input signal to the CPU 901. The user of the shape measuring apparatus 1 can input various data and instruct processing operations to the arithmetic processing unit 20 by operating the input device 909.

  The output device 911 is configured by a device capable of visually or audibly notifying acquired information to the user. Such devices include display devices such as CRT display devices, liquid crystal display devices, plasma display devices, EL display devices and lamps, audio output devices such as speakers and headphones, printer devices, mobile phones, and facsimiles. The output device 911 outputs, for example, results obtained by various processes performed by the arithmetic processing device 20. Specifically, the display device displays the results obtained by various processes performed by the arithmetic processing device 20 as text or images. On the other hand, the audio output device converts an audio signal composed of reproduced audio data, acoustic data, and the like into an analog signal and outputs the analog signal.

  The storage device 913 is a data storage device configured as an example of a storage unit of the arithmetic processing device 20. The storage device 913 includes, for example, a magnetic storage device such as an HDD (Hard Disk Drive), a semiconductor storage device, an optical storage device, or a magneto-optical storage device. The storage device 913 stores programs executed by the CPU 901, various data, various data acquired from the outside, and the like.

  The drive 915 is a recording medium reader / writer, and is built in or externally attached to the arithmetic processing unit 20. The drive 915 reads information recorded on a removable recording medium 921 such as a mounted magnetic disk, optical disk, magneto-optical disk, or semiconductor memory, and outputs the information to the RAM 905. The drive 915 can also write a record on a removable recording medium 921 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory. The removable recording medium 921 is, for example, a CD medium, a DVD medium, a Blu-ray (registered trademark) medium, or the like. Further, the removable recording medium 921 may be a compact flash (registered trademark) (CompactFlash: CF), a flash memory, an SD memory card (Secure Digital memory card), or the like. Further, the removable recording medium 921 may be, for example, an IC card (Integrated Circuit card) on which a non-contact type IC chip is mounted, an electronic device, or the like.

  The connection port 917 is a port for directly connecting a device to the arithmetic processing device 20. Examples of the connection port 917 include a USB (Universal Serial Bus) port, an IEEE 1394 port, a SCSI (Small Computer System Interface) port, and an RS-232C port. By connecting the external connection device 923 to the connection port 917, the arithmetic processing device 20 acquires various data directly from the external connection device 923 or provides various data to the external connection device 923.

  The communication device 919 is a communication interface configured with, for example, a communication device for connecting to the communication network 925. The communication device 919 is, for example, a communication card for wired or wireless LAN (Local Area Network), Bluetooth (registered trademark), or WUSB (Wireless USB). The communication device 919 may be a router for optical communication, a router for ADSL (Asymmetric Digital Subscriber Line), or a modem for various communication. The communication device 919 can transmit and receive signals and the like according to a predetermined protocol such as TCP / IP, for example, with the Internet and other communication devices. In addition, the communication network 925 connected to the communication device 919 is configured by a wired or wireless network, for example, the Internet, a home LAN, an in-house LAN, infrared communication, radio wave communication, satellite communication, or the like. May be.

  Heretofore, an example of the hardware configuration capable of realizing the function of the arithmetic processing device 20 according to the embodiment of the present invention has been shown. Each component described above may be configured using a general-purpose member, or may be configured by hardware specialized for the function of each component. Therefore, it is possible to change the hardware configuration to be used as appropriate according to the technical level at the time of carrying out this embodiment.

  Hereinafter, the shape measuring apparatus and the shape measuring method according to the present invention will be specifically described with reference to Examples and Comparative Examples. In addition, the Example shown below is only an example of the shape measuring apparatus and the shape measuring method which concern on this invention, and the shape measuring apparatus and the shape measuring method which concern on this invention are not limited to the following example. .

Example 1
First, a linear laser beam is generated using a laser light source that emits red light having a wavelength of 660 nm, and the linear laser beam is irradiated to a non-red-hot steel plate provided indoors, thereby performing optical cutting. Images were taken with an imaging device provided with an image side telecentric lens. Here, the focal length f of the lens was 7 mm, and imaging was performed at an angle of view of 63 degrees. At this time, an optical bandpass filter having a bandwidth of 10 nm (multilayer interference filter, transmission center wavelength: 660 nm) is installed on the front stage (object side) or the rear stage (image plane side) of the image side telecentric lens, The obtained images were compared.

FIG. 12 shows the results obtained.
As is clear from FIG. 12, when an optical bandpass filter is installed at the subsequent stage of the image side telecentric lens, linear laser light is reflected over the entire area in the width direction of the image, while the image side telecentric lens When an optical bandpass filter is installed on the front surface, it can be seen that the linear laser beam is reflected only in the central portion in the width direction of the image.

  As described above, by using the imaging device 13 according to the present invention, it is a situation where only the short focus lens (that is, the wide-angle lens) can be used (that is, the distance to the measuring object S is not sufficient). However, it is possible to obtain an appropriate light section image.

(Example 2)
In this example, the measurement object S was a red-hot steel plate having a temperature of 900 ° C. and an emissivity of 0.9 (in other words, a reflectance of 0.1). The wavelength of the laser light source 11 was 640 nm, and the S / N ratio of the target light cut image was 20 or more. In addition, a multilayer interference filter (transmission center wavelength: 640 nm) was used as an optical bandpass filter provided at the subsequent stage of the image side telecentric lens, and the equivalent refractive index n of the interference filter was 1.5. Further, for the used imaging device 13, the minimum brightness necessary for performing the imaging process with a predetermined exposure time in the absence of ambient light is the F value of the imaging device 13 (more specifically, the lens). Was 1.4 mW / cm ² in terms of laser power density.

  FIG. 13 illustrates the distribution of the blackbody radiation spectrum near the wavelength of 640 nm. In FIG. 13, the vertical axis represents the black body radiation intensity (power density, logarithmic display) per 1 nm bandwidth, and the horizontal axis represents the wavelength.

FIG. 13 shows that the black body radiation intensity at a wavelength of 640 nm is about 1.6 × 10 ⁻³ mW / cm ² per 1 nm bandwidth. Therefore, since the emissivity is 0.9, the self-luminous intensity (mW / cm ² ) of the steel sheet is represented by “0.9 × bandwidth (nm) × 1.6 × 10 ⁻³ ”.

On the other hand, from the request that the SN ratio is 20 or more, the laser power density required for the optical cutting line is 20 times the intensity of disturbance light, so that “20 × 0.9 × bandwidth (nm) × 1.6. × 10 ⁻³ ”. Here, since the steel sheet of interest has a reflectance of 0.1, the incident power to the lens needs to be 10 times, so that “10 × 20 × 0.9 × bandwidth (nm) × 1. “6 × 10 ⁻³ = 0.29 × bandwidth (nm)” is the necessary laser power density (mW / cm ² ) from the SN ratio. The relationship “laser power density = 0.29 × bandwidth” is the straight line L1.

  Further, when the relationship between F value and bandwidth is calculated from the relationship of F = 1 / (2 × NA) and the above equation 105, FIG. 14 is obtained. From FIG. 14, when the bandwidth corresponding to the F value = 1.4 of the lens is obtained, it is clear that F1.4 corresponds to the bandwidth of 18 nm.

Accordingly, when a curve L2 that passes through a position of 0.8 mW / cm ² at a position of a bandwidth of 18 nm is obtained, it is as shown in FIG. In FIG. 15, the straight line L1 is also shown. FIG. 15 reveals that the position of the intersection of the straight line L1 and the curved line L2 is (band width, laser power density) = (7 nm, ² mW / cm ² ). As is apparent from FIG. 15, under the imaging conditions as described above, the laser power density of the laser light source 11 needs to be ² mW / cm ² or more, and the upper limit value of the bandwidth of the optical bandpass filter 107. Is 18 nm.

Therefore, optical cutting is performed for each of the condition A in which the laser power density of the laser light source 11 is fixed to 5 mW / cm ² and the bandwidth of the optical bandpass filter 107 is 7 nm and the condition B in which the bandwidth is 30 nm. Images were taken. As is clear from FIG. 15, the condition A is a condition included in the region as shown in FIG. 6B, and the condition B is a condition not included in the region.

  The obtained light section image is shown in FIG. 16, and examples of cross-sectional luminance profiles in the thickness direction of the light section line in the light section image are collectively shown in FIG. In FIG. 17, the vertical axis represents the luminance value of the light section image, and the horizontal axis corresponds to the position in the thickness direction of the light section line (the position in the vertical direction of the light section image in FIG. 16). .

  As apparent from FIGS. 16 and 17, under the condition A, the contrast of the light section image shown in FIG. 16 is good, and the brightness corresponding to the light section line is also present in the cross-sectional brightness profile shown in FIG. 17. You can see that they are concentrated. When the SN ratio of the light section image was calculated for condition A, it exceeded 50.

  On the other hand, under the condition B, the contrast of the light section image shown in FIG. 16 is not good, and the brightness value is widely distributed over the thickness direction of the light section line in the cross-sectional brightness profile shown in FIG. Recognize. When the SN ratio of the light-cut image was calculated for condition B, it was about 3.5.

  In a generally used light cutting method, when generating a concavo-convex image or a luminance image from a light cut image, the center of gravity of the bright line position is often calculated in order to obtain the position of the light cut line. Therefore, under the condition B as shown in FIG. 17, even the background component is mixed in the centroid calculation, so that an error is superimposed on the position of the light cutting line. On the other hand, under the condition A, the luminance value is concentrated in the central portion, and the background component has almost no luminance value. Therefore, under the condition A, it is possible to accurately calculate the position of the light cutting line, and it is possible to further improve the calculation accuracy of the shape calculation process.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Shape measuring apparatus 10 Measuring apparatus 11 Laser light source 13 Imaging apparatus 20 Arithmetic processing apparatus 21 Imaging control part 23 Image processing part 25 Display control part 27 Storage part 101 Camera body 103 Lens 105 Imaging element 107 Optical band pass filter 201 Data acquisition part 203 Shape calculation unit 205 Result output unit

Claims (7)

A laser light source for irradiating the surface of the object to be measured reflecting or radiating light with a linear laser beam and a light cutting line by the laser light on the surface of the object to be measured A measuring device having an imaging device for generating a cut image;
An arithmetic processing device that performs image processing on the light section image generated by the measuring device and calculates the shape of the object to be measured;
With
The imaging device
An image-side telecentric lens that forms an image of the light section line on an image sensor;
An optical bandpass filter having a predetermined bandwidth, disposed between the image side telecentric lens and the image sensor;
A shape measuring device.   The laser power density of the linear laser beam and the bandwidth of the optical bandpass filter are the illuminance on the imaging surface required for imaging the optical cutting line, and the object to be measured is reflected or emitted. The shape measuring apparatus according to claim 1, wherein the shape measuring apparatus is determined based on a signal-to-noise ratio required for disturbance light that is the light.   The shape measuring apparatus according to claim 2, wherein a numerical aperture based on the bandwidth of the optical bandpass filter is set smaller than a numerical aperture determined by an F value of the imaging device. The laser power density on the surface of the object to be measured is
In a plane coordinate system in which the vertical axis represents the laser power density of the linear laser beam and the horizontal axis represents the bandwidth of the optical bandpass filter,
A curve representing the relationship between the laser power density and the bandwidth with a constant signal-to-noise ratio to ambient light, and the relationship between the laser power density and the bandwidth at which the brightness of the image of the light section line on the image plane is constant The shape measuring device according to claim 2, wherein the shape measuring device is set to a value equal to or higher than a laser power density corresponding to an intersection of the curve representing the curve.   The shape measuring apparatus according to claim 4, wherein a curve representing a relationship between a laser power density and a bandwidth at which a signal-to-noise ratio with respect to the disturbance light is constant is a straight line.   The shape measuring apparatus according to any one of claims 1 to 5, wherein a band width of the optical bandpass filter is 5 nm or more and 10 nm or less. A laser light source for irradiating the surface of the object to be measured with a linear laser beam and a light cutting line by the laser light on the surface of the object to be measured are imaged to generate a light section image. An image-side telecentric lens that forms an image of the light-section line on an image sensor, and an optical bandpass filter having a predetermined bandwidth disposed between the image-side telecentric lens and the image sensor. Generating a light-cutting image relating to an object to be measured that reflects or emits light by a measuring device including an imaging device having:
Performing image processing on the light-cut image generated by the measuring device to calculate the shape of the object to be measured;
A shape measuring method.

Images