Spectroscopic measurement device and spectroscopic measurement method

Abstract

A spectroscopic measurement device 1 comprises: a light source 4 that outputs light L to be radiated to a subject S; a spectroscopic unit 5 that disperses the light L so that light rays of a plurality of different wavelengths are distributed in a plane including the movement direction of the subject S; an imaging unit 6 that has a plurality of pixels arranged two-dimensionally and sequentially captures, at different timings, images of the subject S moving in a radiation area R of the light L dispersed by the spectroscopic unit 5; and a generation unit 23 that generates spectroscopic data D of the subject S on the basis of the images captured by the imaging unit 6.

Description

Spectroscopic measurement device and spectroscopic measurement method

[0001] The present disclosure relates to a spectroscopic measurement device and a spectroscopic measurement method.

[0002] An example of a conventional spectroscopic measurement device is the spectroscopic measurement device described in Patent Document 1. This conventional spectroscopic measurement device includes a conveying means for conveying an object to be measured, a line-type hyperspectral camera for acquiring a hyperspectral image of the object to be measured on the conveying means for each field of view extending in a direction perpendicular to the conveying direction of the conveying means, an adjusting means for adjusting the field of view width of the hyperspectral camera, and a control means for controlling at least one of the conveying speed of the object to be measured, the frame rate of the hyperspectral camera, and the field of view width of the hyperspectral camera so that the resolution in the field of view width direction and the resolution in the conveying direction in the hyperspectral image acquired by the hyperspectral camera match.

[0003] Japanese Patent Application Laid-Open No. 2016-156777

[0004] The spectroscopic measurement device described in Patent Document 1 employs a so-called post-spectroscopic method in which diffusely reflected light from an object is separated by a spectroscope disposed immediately before the light receiving unit. However, this type of spectroscopic method tends to have a relatively complicated configuration, and the manufacturing costs of the device are likely to increase.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a spectroscopic measurement device and a spectroscopic measurement method that can perform spectroscopic measurement with a simple configuration and at low cost.

[0006] The gist of the present disclosure is as follows.

[0007] [1] A spectroscopic measurement device comprising: a light source that outputs light to be irradiated onto an object; a spectroscopic unit that disperses the light so that light of multiple different wavelengths is distributed within a plane including the direction of movement of the object; an imaging unit that has multiple pixels arranged two-dimensionally and sequentially captures images of the object moving through an irradiation area of ​​the light dispersed by the spectroscopic unit at different times; and a generation unit that generates spectroscopic data of the object based on the images captured by the imaging unit.

[0008] This spectroscopic measurement device splits light output from a light source into a plane including the direction of movement of the object, sequentially captures images of the object moving through the illuminated area using a two-dimensional array of multiple pixels, and generates spectral data of the object. This spectroscopic measurement device employs a so-called pre-spectroscopic method, in which light split into multiple different wavelengths is irradiated onto the object. A so-called post-spectroscopic method, in which light from the object is split and then captured, requires the incorporation of a spectroscopic component on the imaging side, which can result in increased costs due to the complexity of the configuration. In contrast, the pre-spectroscopic method allows the spectroscopic component to be separated from the imaging side, enabling spectroscopic measurement to be performed inexpensively with a simple configuration.

[0009] [2] The spectroscopic measurement device according to [1], wherein the generation unit generates three-dimensional spectral data by accumulating two-dimensional luminance information of the object in a time axis direction based on the image captured by the imaging unit, thereby enabling suitable measurement of parameters including the thickness of the object based on the spectral data.

[0010] [3] The spectroscopic measurement device according to [1] or [2], wherein the imaging unit is configured with a monochrome camera. In this case, the spectral data of the object is composed only of luminance information at each position on the object. By using a monochrome camera without color film, further cost reduction can be achieved compared to using a color camera.

[0011] [4] The spectroscopic measurement device according to any one of [1] to [3], wherein the imaging unit reads out only a part of a pixel row that is arranged in a direction perpendicular to the moving direction among a plurality of pixels that are two-dimensionally arranged. In this case, the amount of data required to create spectroscopic data can be reduced, thereby speeding up measurement.

[0012] [5] The spectroscopic measurement device according to any one of [1] to [4], wherein the imaging axis of the imaging unit is coaxial with the optical axis of the light traveling from the spectroscopic unit to the object. If the imaging axis is tilted with respect to the optical axis of the dispersed light, wavelength shifts depending on the thickness of the object may occur. In contrast, by making the optical axis of the dispersed light and the imaging axis coaxial, it is possible to avoid wavelength shifts depending on the thickness of the object, thereby improving the measurement accuracy using spectroscopic data.

[0013] [6] The spectroscopic measurement device according to [5], further comprising an optical element for collimating the light directed from the spectroscopic unit to the object. In this case, it is possible to more reliably avoid wavelength shifts depending on the thickness of the object. Therefore, the measurement accuracy based on the spectroscopic data can be further improved.

[0014] [7] The spectroscopic measurement device according to any one of [1] to [6], further comprising a correction unit that corrects a wavelength shift of the light traveling from the spectroscopic unit toward the object. In this case, the measurement accuracy based on the spectroscopic data can be ensured by correcting the wavelength shift.

[0015] [8] The spectroscopic measurement device according to any one of [1] to [7], further comprising a transport unit that moves the object in a predetermined direction at a constant speed. In this case, by keeping the moving speed of the object constant, it is possible to uniquely determine the imaging conditions for the object, and spectroscopic data can be suitably generated.

[0016] [9] A spectroscopic measurement method comprising: an output step of outputting light to be irradiated onto an object; a spectroscopic step of spectroscopically dispersing the light so that light of a plurality of different wavelengths is distributed within a plane including the direction of movement of the object; an imaging step of sequentially capturing images of the object moving through an irradiation area of ​​the light dispersed by the spectroscopic step at different timings using a plurality of pixels arranged two-dimensionally; and a generation step of generating spectroscopic data of the object based on the images captured in the imaging step.

[0017] In this spectroscopic measurement method, light output from a light source is split into a plane including the direction of movement of the object, and the object moving through the irradiated area is sequentially captured using a plurality of pixels arranged two-dimensionally to generate spectral data of the object. This spectroscopic measurement method employs a so-called pre-spectroscopic method in which the object is irradiated with light that has been split into a plurality of different wavelengths in advance. In a so-called post-spectroscopic method in which the light from the object is split into a plurality of different wavelengths and then captured, a spectroscopic configuration must be incorporated into the image capture side, which can result in increased costs due to the complexity of the configuration. In contrast, the pre-spectroscopic method allows the spectroscopic configuration to be separated from the image capture side, enabling spectroscopic measurement to be performed inexpensively with a simple configuration.

[0018]

[10] The spectroscopic measurement method according to [9], wherein the generating step generates three-dimensional spectral data in which two-dimensional luminance information of the object is accumulated in a time axis direction based on the image captured in the imaging step, thereby making it possible to suitably measure parameters including the thickness of the object based on the spectral data.

[0019]

[11] The spectroscopic measurement method according to [9] or

[10] , wherein the imaging step uses a monochrome camera. In this case, the spectral data of the object is composed only of luminance information at each position on the object. By using a monochrome camera without color film, further cost reduction can be achieved compared to using a color camera.

[0020]

[12] The spectroscopic measurement method according to any one of [9] to

[11] , wherein, in the imaging step, only a part of a pixel row arranged in a direction perpendicular to the moving direction among a plurality of pixels arranged two-dimensionally is read out. In this case, the amount of data required to create spectroscopic data can be reduced, thereby speeding up measurement.

[0021]

[13] The spectroscopic measurement method according to any one of [9] to

[12] , wherein the imaging axis in the imaging step is coaxial with the optical axis of the light directed toward the object in the spectroscopic step. If the imaging axis is tilted with respect to the optical axis of the dispersed light, wavelength shifts depending on the thickness of the object may occur. In contrast, by making the optical axis of the dispersed light and the imaging axis coaxial, it is possible to avoid wavelength shifts depending on the thickness of the object, thereby improving the measurement accuracy using spectroscopic data.

[0022]

[14] The spectroscopic measurement method according to

[13] , wherein the spectroscopic step collimates the light directed toward the object. In this case, wavelength shifts depending on the thickness of the object can be more reliably avoided. Therefore, the measurement accuracy based on the spectroscopic data can be further improved.

[0023]

[15] The spectroscopic measurement method according to any one of [9] to

[14] , further comprising a correction step of correcting a wavelength shift of the light directed toward the object. In this case, the correction of the wavelength shift can ensure measurement accuracy using spectroscopic data.

[0024]

[16] The spectroscopic measurement method according to any one of [9] to

[15] , further comprising a transport step of moving the object in a predetermined direction. In this case, by keeping the moving speed of the object constant, it is possible to uniquely determine the imaging conditions for the object, and spectroscopic data can be suitably generated.

[0025] According to the present disclosure, spectroscopic measurement can be performed inexpensively with a simple configuration.

[0026] 1 is a schematic diagram showing a configuration of a spectroscopic measurement device according to an embodiment of the present disclosure; FIG. 2 is a schematic enlarged view of a main part showing how light is spectroscopically separated by a spectroscopic section; (a) to (c) are schematic plan views showing an irradiation area and how an object passes through the irradiation area; FIG. 3 is a schematic diagram showing an example of spectroscopic data; FIG. 4 is a schematic diagram showing film thickness calculation based on spectroscopic data; FIG. 5 is a schematic diagram showing an example of the configuration of a correction section; FIG. 6 is a schematic diagram showing how correction is performed by the correction section; and FIG. 7 is a flowchart showing a spectroscopic measurement method according to an embodiment of the present disclosure. FIG. 8 is a schematic plan view showing a modified example of an imaging section.

[0027] Hereinafter, preferred embodiments of a spectroscopic measurement device and a spectroscopic measurement method according to one aspect of the present disclosure will be described in detail with reference to the drawings.

[0028] Fig. 1 is a schematic diagram showing the configuration of a spectroscopic measurement device according to an embodiment of the present disclosure. The spectroscopic measurement device 1 shown in Fig. 1 is configured as a device that irradiates light L onto an object S and measures the shape of the object S based on the light from the object S. Applications of the spectroscopic measurement device 1 include, for example, film thickness inspection and defect inspection, and foreign matter inspection of food and processed products. In this embodiment, the object S is a film, and the spectroscopic measurement device 1 is configured as a device that measures the film thickness of the film.

[0029] As shown in Fig. 1, the spectroscopic measurement device 1 is configured to include a transport unit 2, a dark box 3, a light source 4, a spectroscopic unit 5, an imaging unit 6, and a control device 7. The transport unit 2 is a part that moves the object S in a predetermined direction at a constant speed. In this embodiment, the transport unit 2 is configured, for example, by a belt conveyor 8, and transports the object S in the horizontal direction at a speed V. The belt conveyor 8 has a belt unit 9 that moves the object S, and an actuator 10 that operates the belt unit 9. The operation of the actuator 10 is controlled by a control unit 22, which will be described later.

[0030] In the following description, the movement direction of the object S in a horizontal plane is defined as the X axis, the direction perpendicular to the movement direction in the horizontal plane is defined as the Y axis, and the vertical direction perpendicular to the X axis and Y axis is defined as the Z axis.

[0031] The dark box 3 is a member that covers the light source 4 and the imaging unit 6. The dark box 3 is arranged to cover a portion of the belt conveyor 8 (a portion including the area R illuminated by the light L from the light source 4). The dark box 3 suppresses the influence of external light on these components, i.e., light other than the light L from the light source 4 toward the object S and the light L from the object S toward the imaging unit 6.

[0032] In this embodiment, the light source 4 and the spectroscopic unit 5 constitute epi-illumination for the object S. The light source 4 is a unit that outputs light L to be irradiated onto the object S. The light source 4 is, for example, a white light source that outputs white light. Examples of white light sources include a white LED, a halogen lamp light source, a supercontinuum light source, and a laser-excited plasma light source. The type of light source 4 is selected depending on the type of object S, etc. The light source 4 is not limited to a white light source as long as it outputs light having a certain wavelength band. The light source 4 may also be a light source that outputs, for example, near-infrared light, infrared light, or ultraviolet light.

[0033] The spectroscopic unit 5 is a part that splits the light L from the light source 4. The spectroscopic unit 5 splits the light L so that light of a plurality of different wavelengths is distributed within a plane that includes the direction of movement of the object S. In this embodiment, as shown in FIG. 2 , the spectroscopic unit 5 is configured with an irradiation area 11, a beam splitter 12, and a field lens 13.

[0034] The illumination area 11 is an optical element that separates the light L from the light source 4. The illumination area 11 separates the white light L into wavelengths (rainbow colors) and generates multiple planar light beams with different wavelengths in a direction intersecting the optical axis. The beam splitter 12 is an optical element that reflects a portion of the incident light and transmits a portion of the light. The beam splitter 12 reflects a portion of the light L separated by the illumination area 11 in the Z-axis direction. The beam splitter 12 may be configured, for example, by a half mirror.

[0035] The light L that passes through the beam splitter 12 becomes planar light that spreads in the X-axis and Y-axis directions, and is collimated by the field lens 13 to form a two-dimensional irradiation area R on the belt portion 9. The field lens 13 is a lens that is disposed near the image and adjusts the direction of travel of the light L near the image. The field lens 13 makes the image clear not only near the center of the collimated light L but also near the periphery.

[0036] In the illumination area R, as shown in Figures 3(a) to 3(c), the X-axis direction corresponds to the wavelength change direction of the light L dispersed by the spectroscopic unit 5. Here, for example, light of different wavelengths is arranged in the order of red, orange, yellow, green, blue, indigo, and purple from the front side to the back side in the conveyance direction. Light of the same wavelength extends in the Y-axis direction. The object S is moved in the X-axis direction by the belt unit 9 at a constant speed V, and passes through the illumination area R in order from red to purple.

[0037] The imaging unit 6 is a part that sequentially captures images of the object S moving within the irradiation area R of the light L dispersed by the spectroscopic unit 5 at different timings. The imaging unit 6 has a plurality of pixels arranged two-dimensionally. The imaging unit 6 is configured, for example, by a CMOS camera or a CCD camera. Here, the light L dispersed by the spectroscopic unit 5 is incident on the imaging unit 6, reflected by the object S. The light incident on the imaging unit 6 is not limited to reflected light, and may be scattered light from the object S or fluorescence generated by the object S when irradiated with the light L. When the light L is near-infrared light to infrared light, the imaging unit 6 may be configured by an InGaAs camera, an InSb camera, an HgCdTe (MCT) camera, or the like. The imaging unit 6 outputs the image of the object S acquired by imaging to the control device 7.

[0038] In this embodiment, the imaging unit 6 is configured with a monochrome camera 15. The monochrome camera 15 is a camera without color film, and each pixel outputs only brightness information at each position on the object S. Also, in this embodiment, as shown in FIG. 2 , the imaging axis P2 of the imaging unit 6 is coaxial with the optical axis P1 of the light L traveling from the spectroscopic unit 5 toward the object S. In the example of FIG. 2 , the optical axis P1 of the light L traveling from the spectroscopic unit 5 toward the object S and the imaging axis P2 of the imaging unit 6 both lie along the Z-axis direction.

[0039] Frame rate F in the imaging unit 6 ｒ The relationship between F and the moving speed V of the object S is expressed by the following formula (1). ｖ is the field of view in the Y-axis direction of the imaging unit 6, and P ｎｙ is the number of pixels in the Y-axis direction in the imaging unit 6.

[0040] The imaging unit 6 captures an image once every time the object S moves by one pixel in the X-axis direction. The number of times imaging is performed by the imaging unit 6 is greater than when a line scan camera is used. If the number of pixel rows in the X-axis direction of the irradiation area R is n, then (n-1) images are captured from the time the object S reaches a position corresponding to the first pixel row in the X-axis direction of the irradiation area R until it reaches a position corresponding to the (n-1)th pixel row in the X-axis direction. Thereafter, as in the case of using a line scan camera, images are captured a number of times corresponding to the length of the object S in the X-axis direction until the object S leaves the irradiation area R.

[0041] The control device 7 is physically configured as a computer system including memories such as RAM and ROM, a processor (arithmetic circuit) such as a CPU, a communication interface, a storage unit such as an SSD or a hard disk, and a display unit 21 (see FIG. 1 ) such as a display. The control device 7 functions by executing a program stored in the memory with the CPU of the computer system. The control device 7 may also be configured as a microcomputer, a programmable logic controller (PLC), a field-programmable gate array (FPGA), or the like.

[0042] 1 , the control device 7 functionally includes a control unit 22, a generation unit 23, and a calculation unit 24. The control unit 22 is a part that controls the operation of the spectroscopic measurement device 1. The control unit 22 controls, for example, the on / off of the light source 4, the frame rate of imaging in the imaging unit 6, the moving speed of the object S on the belt conveyor 8, and the like.

[0043] The generation unit 23 is a part that generates spectral data D of the object S based on the image captured by the imaging unit 6. The generation unit 23 receives the image output from the imaging unit 6 and generates three-dimensional spectral data in which two-dimensional luminance information of the object S is accumulated in the time axis direction. The generation unit 23 outputs the generated spectral data D to the calculation unit 24.

[0044] 4 is a diagram showing an example of spectral data. As described above, the spectroscopic measurement device 1 captures an image every time the object S moves by one pixel in the X-axis direction. Therefore, the number of pixels in the X-axis direction in the image capturing unit 6 is P ｎｘ The number of pixels in the Y-axis direction is P ｎｙ In this case, the spectral data D is expressed as follows: ｎｘ ×P ｎｙ The two-dimensional luminance information is expressed as t １ ~t ｎ This will result in three-dimensional spectroscopic data accumulated up to the present.

[0045] The spectrum S of the luminance information obtained from the spectral data D is expressed by the following equation (2). Ｌ is expressed by the following equation (3).

[0046] The calculation unit 24 is a part that calculates predetermined parameters of the object S based on the spectral data D. Here, the calculation unit 24 calculates the thickness of the film, which is the object S, based on the spectral data D output from the generation unit 23. FIG. 5 is a diagram that schematically shows the calculation of the thickness based on the spectral data. As shown in FIG. 5, the calculation unit 24 calculates the spectrum S of the luminance information at, for example, arbitrary positions k1 and k2 of the object S. ｋ１ , S ｋ２ The calculation unit 24 calculates the film thickness of the object S at the positions k1 and k2 based on the spacing between the interference fringes obtained by plotting the brightness against the wavelength, and displays the calculation results on the display unit 21.

[0047] In this embodiment, the spectroscopic measurement device 1 includes a correction unit 31 that corrects wavelength shifts of light L directed from the spectroscopic unit 5 to the target S. The wavelength shift here is assumed to be a case where the wavelength change direction of the light L dispersed by the spectroscopic unit 5 does not match the X-axis direction. The correction unit 31 is configured by a plurality of bandpass filters 33 arranged in a ring shape on a plate-like member 32, as shown in FIG. 6, for example. The plurality of bandpass filters 33 are set according to the wavelengths of the light L dispersed by the spectroscopic unit 5. Here, in the disk-shaped plate-like member 32, center wavelengths λ corresponding to seven colors, for example, red, orange, yellow, green, blue, indigo, and purple, are corrected. １ , λ ２、 …, λ ７ The seven band pass filters 33 are arranged in a circular ring shape.

[0048] When the wavelength shift of the light L is corrected by the correction unit 31, the irradiation area R is imaged through each bandpass filter 33. When imaging the irradiation area R, the image may be taken through the object S or without the object S. Next, as shown in FIG. 7, the central wavelength λ of each bandpass filter 33 is calculated. １ , λ ２、 …, λ ７ and the coordinate X in the X-axis direction corresponding to each of these center wavelengths. λ１ , X λ２ , …, X λ７ For each coordinate in the Y-axis direction, the relationship between the coordinate X in the X-axis direction and the wavelength is corrected by polynomial approximation. The polynomial for each coordinate Yn in the Y-axis direction is, for example, λ(X, Yn)=a+bx+cx ２ (where a to c are constants.) Such correction calculations may be performed using a field-programmable gate array (FPGA) mounted on the imaging unit 6 or a correction file in software.

[0049] 8 is a flowchart showing a spectroscopic measurement method according to an embodiment of the present disclosure. As shown in FIG. 8, the spectroscopic measurement method according to this embodiment includes a correction step S01, an output step S02, a spectroscopic step S03, a transport step S04, an imaging step S05, a generation step S06, a calculation step S07, and a display step S08. The spectroscopic measurement method according to this embodiment is performed using, for example, the spectroscopic measurement device 1 described above.

[0050] The correction step S01 is a step of correcting the wavelength shift of the light L traveling toward the object S. Here, the above-described correction unit 31 is used to capture an image of the irradiation area R via each band-pass filter 33. Next, the central wavelength λ of each band-pass filter 33 is corrected. １ , λ ２、 …, λ ７ and the coordinate X in the X-axis direction corresponding to each of these center wavelengths. λ１ , X λ２ , …, X λ７ Using the above formula, the relationship between the coordinate in the X-axis direction and the wavelength is corrected by polynomial approximation for each coordinate in the Y-axis direction. Note that the correction step S01 does not need to be performed every time measurement of the object S is started, and may be omitted and the process may proceed to the output step S02.

[0051] The output step S02 is a step of outputting light L to be irradiated onto the object S. In the output step S02, the light source 4 is turned on, and the light L from the light source 4 is input to the spectroscopic unit 5. The spectroscopic step S03 is a step of spectroscopically separating the light L. In the spectroscopic step S03, the light L from the light source 4 is separated by the irradiation area 11, and the separated light L is reflected in the Z-axis direction by the beam splitter 12. Then, the light L is collimated by the field lens 13, and an irradiation area R is formed on the conveying unit 2 (belt unit 9).

[0052] The conveying step S04 is a step of moving the object S in a predetermined direction. In the conveying step S04, the belt conveyor 8, which is the conveying unit 2, is driven to move the object S placed on the belt unit 9 horizontally toward the irradiation area R at a constant speed. The imaging step S05 is a step of capturing an image of the object S using a plurality of pixels arranged two-dimensionally. Here, the imaging axis P2 is coaxial with the optical axis of the light L directed toward the object S, and the object S moving in the irradiation area R is sequentially captured at different timings by the monochrome camera 15.

[0053] The generating step S06 is a step of generating spectral data D of the object S. In the generating step S06, three-dimensional spectral data is generated by accumulating two-dimensional luminance information of the object S in the time axis direction based on the image captured in the imaging step S05.

[0054] The calculation step S07 is a step of calculating predetermined parameters of the object S based on the spectral data D. Here, the film thickness of the object S is calculated based on the spectral data D generated in the generation step S06. The display step S08 is a step of displaying the calculation results. In the display step S08, the calculation results in the calculation step S07 are displayed on the display unit 21.

[0055] As described above, in this embodiment, the light L output from the light source 4 is split into a plane including the direction of movement of the object S, and the object S moving in the irradiation area R is sequentially imaged using a plurality of pixels arranged two-dimensionally to generate spectral data D of the object S. This embodiment employs a so-called pre-spectroscopic method in which the object S is irradiated with light L that has been split into a plurality of different wavelengths in advance. In a so-called post-spectroscopic method in which light from the object is split into a plurality of wavelengths and then imaged, a spectroscopic configuration must be incorporated on the imaging side, which can result in increased costs due to the complexity of the configuration. In contrast, in the pre-spectroscopic method, the spectroscopic configuration can be separated from the imaging side, making it possible to perform spectroscopic measurement with a simple configuration and at low cost.

[0056] In this embodiment, the generation unit 23 generates three-dimensional spectral data in which two-dimensional luminance information of the object S is accumulated in the time axis direction, based on the image captured by the imaging unit 6. This makes it possible to preferably measure parameters including the thickness of the object S based on the spectral data D.

[0057] In this embodiment, the imaging unit 6 is configured with a monochrome camera 15. In this case, the spectral data D of the object S is configured only with luminance information at each position on the object S. By using the monochrome camera 15 without color film, it is possible to achieve even lower costs than when a color camera is used.

[0058] In this embodiment, the imaging axis P2 of the imaging unit 6 is coaxial with the optical axis P1 of the light L traveling from the spectroscopic unit 5 toward the object S. If the imaging axis is inclined with respect to the optical axis of the dispersed light, it is conceivable that a wavelength shift will occur depending on the thickness of the object. In contrast, by making the optical axis P1 of the dispersed light L and the imaging axis P2 coaxial, it is possible to avoid a wavelength shift depending on the thickness of the object S, thereby improving the measurement accuracy using the spectroscopic data D.

[0059] In this embodiment, an optical element (field lens 13) is provided that collimates the light L traveling from the spectroscopic unit 5 toward the target S. In this case, it is possible to more reliably avoid wavelength shifts that depend on the thickness of the target S. Therefore, the measurement accuracy based on the spectral data D is further improved.

[0060] In this embodiment, a correction unit 31 is provided that corrects the wavelength shift of the light L traveling from the spectroscopic unit 5 toward the target S. In this case, the measurement accuracy based on the spectral data D can be ensured by correcting the wavelength shift.

[0061] In this embodiment, a conveying unit 2 is provided that moves the object S in a predetermined direction at a constant speed. In this case, by keeping the moving speed of the object S constant, it becomes possible to uniquely determine the imaging conditions for the object S, and the spectral data D can be suitably generated.

[0062] The present disclosure is not limited to the above-described embodiment. For example, in the above-described embodiment, the optical axis P1 of the light L traveling from the spectroscopic unit 5 toward the target S and the imaging axis P2 of the imaging unit 6 both extend along the vertical direction, and the optical axis P1 and the imaging axis P2 are coaxial. However, the optical axis P1 and the imaging axis P2 may be non-coaxial. In this case, for example, the imaging axis P2 may be aligned along the vertical direction, and the optical axis P1 of the light L separated by the spectroscopic unit 5 may be tilted at a predetermined angle from the vertical direction. In this case, the field lens 13 may be omitted, and the illumination area R may be formed directly with the light L separated by the spectroscopic unit 5.

[0063] In the above embodiment, the light from the light source 4 is split by the irradiation area 11, but the optical element used for splitting is not limited to the irradiation area 11, and a reflective or transmissive grating or the like may also be used. In the above embodiment, the light L split by the spectroscopic unit 5 is reflected by the object S and the image is captured by the imaging unit 6. However, for example, the imaging unit 6 may be disposed on the belt conveyor 8 side, and the transmitted light of the light L split by the spectroscopic unit 5 that passes through the object S may be captured by the imaging unit 6.

[0064] In the above embodiment, the imaging unit 6 reads out all of the two-dimensionally arranged pixels. However, as shown in FIG. 9 , it is also possible to read out only a portion of the pixel rows arranged in the Y-axis direction from among the multiple two-dimensionally arranged pixels. In this case, the amount of data required to create the spectral data D can be reduced, thereby speeding up the measurement. In the example of FIG. 9 , reading is performed intermittently every four pixel rows. In this case, the number of wavelengths used to measure the object S is reduced to one-quarter, but the measurement speed can be increased fourfold.

[0065] In the above embodiment, the plate-like member 32 having the plurality of band-pass filters 33 is used as the correction unit 31, but the configuration of the correction unit 31 is not limited to this. For example, the correction unit 31 can also be configured using a mercury lamp. In this case, for example, the mercury lamp is disposed in place of the light source 4 instead of the light source 4. The light from the mercury lamp is split into a plurality of bright lines by the spectroscopic unit 5, which are irradiated onto the irradiation area R, and an image is captured by the imaging unit 6. Each bright line spectrum λ of the mercury lamp Ｈｇ１ , λ Ｈｇ２、 …, λＨｇｎ and the coordinates X in the X-axis direction corresponding to each of these emission line spectra. λ１ , X λ２ , …, X λｎ Using this, the relationship between the coordinate in the X-axis direction and the wavelength is corrected for each coordinate in the Y-axis direction by polynomial approximation. The correction unit 31 using a mercury lamp does not require switching of band-pass filters, etc., and can correct wavelength deviations in a shorter time. In addition, since the correction is performed on atomic beams, the accuracy of the correction can be improved.

[0066] 1...spectroscopic measurement device, 2...transport unit, 4...light source, 5...spectroscopic unit, 6...imaging unit, 13...field lens (optical element), 15...monochrome camera (imaging unit), 23...generation unit, 31...correction unit, S...object, L...light, R...irradiation area, D...spectroscopic data, P1...optical axis, P2...imaging axis

Claims

1. A spectroscopic measurement device comprising: a light source that outputs light to be irradiated onto an object; a spectroscopic unit that disperses the light so that light of multiple different wavelengths is distributed in a plane including the direction of movement of the object; an imaging unit having multiple pixels arranged two-dimensionally, and that sequentially captures images of the object moving through an irradiation area of ​​the light dispersed by the spectroscopic unit at different timings; and a generation unit that generates spectroscopic data of the object based on the images captured by the imaging unit.

2. A spectroscopic measurement device as described in claim 1, wherein the generation section generates three-dimensional spectroscopic data by accumulating two-dimensional luminance information of the object in the time axis direction based on the image captured by the imaging section.

3. The spectroscopic measuring device according to claim 1 or 2, wherein the imaging unit is constituted by a monochrome camera.

4. A spectroscopic measurement device according to any one of claims 1 to 3, wherein the imaging unit reads out only a portion of a pixel row that is arranged in a direction perpendicular to the direction of movement out of a plurality of pixels that are arranged two-dimensionally.

5. A spectroscopic measuring device according to any one of claims 1 to 4, wherein the imaging axis of the imaging section is coaxial with the optical axis of the light traveling from the spectroscopic section to the object.

6. The spectroscopic measuring device according to claim 5, further comprising an optical element for converting the light traveling from said spectroscopic section toward said object into parallel light.

7. A spectroscopic measuring device according to any one of claims 1 to 6, further comprising a correction section that corrects a wavelength shift of the light traveling from the spectroscopic section toward the object.

8. The spectroscopic measuring device according to any one of claims 1 to 7, further comprising a transport unit for moving the object in a predetermined direction at a constant speed.

9. A spectroscopic measurement method comprising: an output step of outputting light to be irradiated onto an object; a spectroscopic step of spectroscopically dispersing the light so that light of a plurality of different wavelengths is distributed within a plane including the direction of movement of the object; an imaging step of sequentially capturing images at different times of the object moving through an irradiation area of ​​the light dispersed by the spectroscopic step using a plurality of pixels arranged two-dimensionally; and a generation step of generating spectroscopic data of the object based on the images captured in the imaging step.

10. A spectroscopic measurement method according to claim 9, wherein said generating step generates three-dimensional spectroscopic data in which two-dimensional luminance information of the object is accumulated in the time axis direction based on the image captured in said imaging step.

11. The spectroscopic measurement method according to claim 9 or 10, wherein the imaging step uses a monochrome camera.

12. A spectroscopic measurement method according to any one of claims 9 to 11, wherein in the imaging step, only a portion of a pixel row arranged in a direction perpendicular to the direction of movement is read out from among a plurality of pixels arranged two-dimensionally.

13. A spectroscopic measurement method according to any one of claims 9 to 12, wherein an imaging axis in the imaging step is coaxial with an optical axis of the light directed toward the object in the spectroscopic step.

14. The spectroscopic measurement method according to claim 13, wherein said spectroscopic step comprises converting said light directed toward said object into parallel light.

15. A spectroscopic measurement method according to any one of claims 9 to 14, further comprising a correction step of correcting a wavelength shift of the light directed toward the object.

16. The spectroscopic measurement method according to any one of claims 9 to 15, further comprising a conveying step of moving the object in a predetermined direction.

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