JP2019184560A - Non-contact spectrometry device and non-contact spectrometry method - Google Patents

Abstract

An object of the present invention is to provide a non-contact spectrometer for easily evaluating a measurement object. A non-contact spectrometer 1A includes a measurement head 2A and a controller 3. The measurement head 2A includes a light source 10, a spectroscope 20, an imaging unit 30, a first polarizer 41, a second polarizer 42, a shutter 51, a beam splitter 52, a lens 54, and an aperture 55. The light source 10 outputs broadband white light. The spectroscope 20 acquires the spectrum of the light that has arrived from the measurement target Sa. The first polarizer 41 is provided in the first optical path from the light source 10 to the measurement target, and outputs light of a specific polarization among the light output from the light source 10 to the measurement target. The second polarizer 42 is provided in the middle of a second optical path from the object to be measured to the spectroscope 20, and receives light generated by the object to be measured and converts the light excluding the light of the specific polarization into a spectroscope. Output to 20. [Selection diagram] Fig. 1

Description

  The present invention relates to an apparatus and method for performing non-contact spectroscopic measurement.

  By obtaining a spectrum of light generated in the measurement object when the measurement object is irradiated with light using a spectroscope, the measurement object can be evaluated based on the spectrum. There are various objects for such spectroscopic measurement. Non-Patent Document 1 describes that the sugar content of fruits, the taste of rice, the fat of beef, the fat of fish, the nutritional components of feed, the ingredients of building materials, etc. can be evaluated non-destructively by spectroscopic measurement. Yes.

  For example, if the components of agricultural products can be evaluated by non-destructive spectroscopic measurement, the quality of the agricultural products can be easily controlled, and the appropriate harvest time of the agricultural products can be clarified. Improvements and production efficiency improvements are expected. When using food as a measurement object, it is important to perform non-contact spectroscopic measurement in order to avoid contamination of the measurement object in addition to non-destructive spectroscopic measurement.

  Patent Document 1 discloses an invention of an apparatus capable of performing non-destructive and non-contact spectroscopic measurement. The non-contact spectroscopic measurement device described in this document measures the intensity of sunlight reflected by a plant at each of a plurality of specific wavelengths, and measures the intensity of sunlight directly incident to obtain the former intensity. The latter intensity is corrected. And this non-contact spectroscopic measurement apparatus evaluates the growth condition of a plant based on the intensity | strength after correction | amendment in each of several specific wavelength.

Japanese Patent No. 4243014

Okura Tsutomu, “Near Infrared Spectroscopy for Living Everyday Life”, Applied Physics, Vol. 87, No. 1, pp. 6-10 (2018)

  However, in the conventional spectroscopic measurement technique including the invention described in Patent Document 1, the acquired spectrum depends on the setting of the optical system between the non-contact spectroscopic measurement device and the measurement target, and the measurement target is set appropriately. It is difficult to evaluate. Regarding this, Non-Patent Document 1 states that “the observed spectrum is affected by the arrangement of the sample optical system”, and “refraction / scattering and surface reflection do not reflect material information”. In addition, it is described that it is important for the optical system to “select an arrangement that avoids specular reflection”.

  On the other hand, there is a demand for a non-contact spectroscopic measurement apparatus that is small in size and portable and that is easy to perform spectroscopic measurement in the field. However, since it is not easy to appropriately set the optical system between such a non-contact spectroscopic measurement apparatus and the measurement object, it is more difficult to properly evaluate the measurement object.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a non-contact spectroscopic measurement apparatus and a non-contact spectroscopic measurement method that can easily evaluate a measurement object appropriately.

  The non-contact spectroscopic measurement apparatus of the present invention includes (1) a light source that outputs broadband light, and (2) provided in the middle of the first optical path from the light source to the measurement object, and inputs the light output from the light source. A first polarizer that outputs light of a specific polarization to the measurement object, (3) a spectroscope that obtains the spectrum of the light that has arrived among the light generated by the measurement object, and (4) from the measurement object A second polarizer that is provided in the middle of the second optical path to the spectroscope, inputs the light generated by the measurement object, and outputs the light other than the specific polarized light to the spectroscope, and (5) outputs from the light source. From the first spectrum acquired by the spectrometer during the period when the measurement object is irradiated with the measured light, the second spectrum acquired by the spectrometer during the period when the light output from the light source is not irradiated to the measurement object The third spectrum is obtained as a result of the subtraction, and the third spectrum is obtained as an output light spectrum of the light source. In search of fourth spectra as a result of the division, and an arithmetic unit for evaluating the measurement object based on the fifth spectrum obtained by processing the fourth spectral or fourth spectrum. The calculation unit preferably obtains a fifth spectrum by standardizing the fourth spectrum and evaluates the measurement object based on the fifth spectrum.

  In the non-contact spectroscopic measurement apparatus of the present invention, it is preferable that the first optical path and the second optical path are common optical paths in which light enters and exits the measurement object. The first polarizer and the second polarizer may be polarizers that output linearly polarized light. The first polarizer and the second polarizer may be polarizers that output circularly polarized light. The first polarizer and the second polarizer are polarizers that output circularly polarized light, and may be provided as a common polarizer in the middle of a common optical path.

  The non-contact spectroscopic measurement apparatus of the present invention is (1) provided in the middle of the second optical path, splits the light from the measurement object into two to be the first branched light and the second branched light, and splits the first branched light. A beam splitter that outputs to the detector, (2) an imaging unit that receives the second branched light output from the beam splitter and images the measurement object, and (3) an image of the measurement object that is imaged by the imaging unit It is preferable to further include a display unit for displaying. The display unit preferably displays a range in which the spectroscope performs spectroscopic measurement in the image of the measurement object. The non-contact spectroscopic measurement apparatus of the present invention includes (1) a laser light source that outputs laser light, and (2) a light source that is provided in the middle of the second optical path and outputs light from the measurement object to the spectrometer. It is preferable to further include a beam splitter that outputs the laser beam from the laser beam to the measurement object along the second optical path. Moreover, it is preferable that the range in which the measurement object is irradiated with the light through the first optical path has a visible spot shape.

  In the non-contact spectroscopic measurement method of the present invention, (1) a broadband light outputted from a light source is measured as light of a specific polarization by a first polarizer provided in the middle of a first optical path from the light source to the measurement object. The target object is irradiated, and during the irradiation period, light of a specific polarization is removed from the light generated in the measurement object by the second polarizer provided in the middle of the second optical path from the measurement object to the spectrometer. A first spectrum acquisition step in which light is incident on the spectrometer and the first spectrum of the incident light is acquired by the spectrometer; (2) in a period in which the measurement object is not irradiated with the light output from the light source; A second spectrum acquisition step of acquiring the second spectrum of the light incident on the spectrometer by the spectrometer; (3) a subtraction step of obtaining a third spectrum as a result of subtracting the second spectrum from the first spectrum; ) 3rd spectrum as light source A division step for obtaining a fourth spectrum as a result of division by the output light spectrum of (5), and (5) an evaluation step for evaluating the measurement object based on the fourth spectrum or the fifth spectrum obtained by processing the fourth spectrum; . The non-contact spectroscopic measurement method of the present invention preferably further includes a standardization step of standardizing the fourth spectrum to obtain the fifth spectrum, and evaluating the measurement object based on the fifth spectrum in the evaluation step. is there.

  In the non-contact spectroscopic measurement method of the present invention, it is preferable that the first optical path and the second optical path have a common optical path in a portion where light enters and exits the measurement object. The first polarizer and the second polarizer may be polarizers that output linearly polarized light. The first polarizer and the second polarizer may be polarizers that output circularly polarized light. The first polarizer and the second polarizer are polarizers that output circularly polarized light, and may be provided as a common polarizer in the middle of a common optical path.

  In the non-contact spectroscopic measurement method of the present invention, a beam splitter provided in the middle of the second optical path splits the light from the measurement object into two to be the first branched light and the second branched light, and the first branched light is converted into the first branched light. In addition to outputting to the spectroscope, the second branched light is output to the imaging unit, the measurement target is imaged by the imaging unit that has received the second branched light, and the image of the measurement target captured by the imaging unit is displayed by the display unit. It is preferable to display. It is preferable that the display unit displays the range in which the spectroscope performs spectroscopic measurement in the image of the measurement object. The non-contact spectroscopic measurement method of the present invention outputs the light from the measurement object to the spectroscope by the beam splitter provided in the middle of the second optical path, and transmits the laser light from the laser light source along the second optical path. It is preferable to output to the measurement object. Moreover, it is preferable that the range in which the measurement object is irradiated with the light through the first optical path has a visible spot shape.

  According to the present invention, it is easy to appropriately evaluate a measurement object.

FIG. 1 is a diagram illustrating a configuration of a non-contact spectrometer 1A according to the first embodiment. FIG. 2 is a diagram illustrating an optical system from the light source 10 to the spectroscope 20 in the measurement head 2A of the non-contact spectrometer 1A of the first embodiment. FIG. 3 is a diagram illustrating a configuration of a non-contact spectrometer 1B according to the second embodiment. FIG. 4 is a diagram illustrating a configuration of a non-contact spectrometer 1C according to the third embodiment. FIG. 5 is a diagram illustrating a configuration of a non-contact spectrometer 1D according to the fourth embodiment. FIG. 6 is a diagram showing a configuration of a non-contact spectrometer 1E according to the fifth embodiment. FIG. 7 is a flowchart of the main routine of the non-contact spectroscopic measurement method of this embodiment. FIG. 8 is a flowchart of a subroutine of the non-contact spectroscopic measurement method of the present embodiment. FIG. 9 is a diagram schematically showing the output light spectrum Sp0 of the light source 10. As shown in FIG. FIG. 10 is a diagram schematically showing the first spectrum Sp1. FIG. 11 is a diagram schematically showing the second spectrum Sp2. FIG. 12 is a diagram schematically illustrating the third spectrum Sp3. FIG. 13 is a diagram schematically illustrating the fourth spectrum Sp4. FIG. 14 is a diagram schematically showing the fifth spectrum Sp5. FIG. 15 is a graph showing the directivity in the vertical direction in the spectrometer 20. FIG. 16 is a graph showing the directivity in the horizontal direction in the spectrometer 20. FIG. 17 is a diagram illustrating the first spectrum Sp1 acquired in the first spectrum acquisition step St11. FIG. 18 is a diagram illustrating the second spectrum Sp2 acquired in the second spectrum acquisition step St12. FIG. 19 is a diagram illustrating the third spectrum Sp3 (acquired in the third spectrum acquisition step St13. FIG. 20 is a diagram illustrating the output light spectrum Sp0 and the third spectrum Sp3 of the light source 10. FIG. 21 is a diagram illustrating the fourth spectrum Sp4 acquired in the fourth spectrum acquisition step St14. FIG. 22 is a diagram illustrating the fourth spectrum Sp4 acquired in the fourth spectrum acquisition step St14 using each of the 16 Komatsuna leaves as the measurement object. FIG. 23 is a diagram illustrating the fifth spectrum Sp5 acquired in the fifth spectrum acquisition step St15 using each of the 16 Komatsuna leaves as the measurement object. FIG. 24 is a graph showing the correlation between the SPAD estimated value based on the fifth spectrum Sp5 and the SPAD actual measurement value by the SPAD meter. FIG. 25 is a diagram illustrating spectra Sp1 to Sp3 when a fluorescent lamp is used as the ambient environment light source. FIG. 26 is a diagram illustrating spectra Sp1 to Sp3 when a xenon lamp is used as the ambient environment light source. FIG. 27 is a diagram showing spectra Sp1 to Sp3 when a red lamp is used as the ambient environment light source. FIG. 28 is a diagram illustrating a third spectrum Sp3 when a fluorescent lamp, a xenon lamp, and a red lamp are used as ambient environment light sources. FIG. 29 is a diagram showing a spectrum obtained by performing standardization processing by SNV correction on the third spectrum Sp3 when each of the fluorescent lamp, the xenon lamp, and the red lamp is used as the ambient environment light source. FIG. 30 is a diagram illustrating a second spectrum Sp2 when a fluorescent lamp, a xenon lamp, and a red lamp are used as ambient environment light sources. FIG. 31 is a diagram illustrating a spectrum obtained by performing standardization processing by SNV correction on the second spectrum Sp2 when a fluorescent lamp, a xenon lamp, and a red lamp are used as the ambient environment light sources. FIG. 32 is a diagram illustrating a configuration of a non-contact spectrometer 1F according to the sixth embodiment. FIG. 33 is a diagram showing a configuration of a non-contact spectrometer 1G of the seventh embodiment. FIG. 34 is a diagram showing a configuration of a non-contact spectrometer 1H of the eighth embodiment. FIG. 35 is a diagram illustrating a configuration of a non-contact spectrometer 1I according to the ninth embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. The present invention is not limited to these exemplifications, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  First, the non-contact spectrometer 1A of the first embodiment will be described. FIG. 1 is a diagram illustrating a configuration of a non-contact spectrometer 1A according to the first embodiment. The non-contact spectrometer 1A includes a measurement head 2A and a control device 3. The measurement head 2A includes a light source 10, a spectroscope 20, an imaging unit 30, a first polarizer 41, a second polarizer 42, a shutter 51, a beam splitter 52, a lens 54, and a diaphragm 55. FIG. 2 is a diagram illustrating an optical system from the light source 10 to the spectroscope 20 in the measurement head 2A of the non-contact spectrometer 1A of the first embodiment. In FIG. 2, the shutter 51 and the beam splitter 52 are not shown.

  The light source 10 outputs broadband light. As the light source 10, a light source 10 that outputs light in a wavelength band corresponding to a measurement object Sa that is an object of spectroscopic measurement and an evaluation item by spectroscopic measurement is used. The output wavelength band of the light source 10 may include an infrared region or a visible region, and may include an ultraviolet region. The light source 10 may be, for example, a xenon lamp, a halogen lamp, an LED (Light Emitting Diode), a fluorescent lamp, a discharge lamp, or the like. The light source 10 may be one that can be repeatedly turned on / off in units of seconds, for example, and capable of performing a strobe operation that emits high-intensity light in a short time (for example, a xenon flash light source, a single-lens light source). A flash lamp for a reflex camera, an LED flash lamp for a compact camera, or the like.

  The first polarizer 41 and the shutter 51 are provided in the middle of the first optical path from the light source 10 to the measurement object Sa. The first polarizer 41 receives light output from the light source 10 and outputs light of specific polarization (linear polarization in a specific direction or circular polarization in a specific rotation direction) to the measurement object Sa. The shutter 51 controls irradiation / non-irradiation of the light output from the light source 10 to the measurement object Sa. The shutter 51 may control irradiation / non-irradiation of light to the measurement target Sa by inserting / saving a shielding plate with respect to the first optical path from the light source 10 to the measurement target Sa. Further, the shutter 51 may control the irradiation / non-irradiation of light to the measuring object Sa by transmitting / blocking light of the liquid crystal panel disposed on the first optical path. The irradiation / non-irradiation of light to the measuring object Sa may be controlled by the emission / non-emission of light from the light source 10 without providing the shutter 51. In addition, by repeating irradiation / non-irradiation of light to the measurement object Sa a plurality of times in a short cycle (for example, several tens to several hundreds of milliseconds), it is possible to follow a short time change of ambient ambient light such as sunlight. In this case, the irradiation time and the non-irradiation time may be set to 100 ms, for example.

  The second polarizer 42, the lens 54, and the diaphragm 55 are provided in the middle of the second optical path from the measurement object Sa to the spectrometer 20. The second polarizer 42 receives the light generated by the measurement object Sa, and outputs the light excluding the specific polarized light to the spectrometer 20. The lens 54 receives light generated in the light irradiation region of the measurement object Sa and passed through the second polarizer 42, and forms an image of the light irradiation region on the imaging surface 22. The light entrance slit 21 of the spectroscope 20 is on the image plane 22. The diaphragm 55 is provided at the rear stage of the lens 54 and restricts the direction (directivity) of light incident on the light incident slit 21 of the spectrometer 20.

  By appropriately selecting the focal length of the lens 54 and the aperture diameter of the aperture 55, even if the measurement object Sb is located farther than 1/2 of the hyperfocal distance of the lens 54, the measurement object Sb Can be formed on the imaging plane 22. Thereby, the freedom degree of the setting of the distance between measuring object Sa and an apparatus can be raised. Further, as the size of the light incident slit 21 of the spectroscope 20 is smaller, the range of spectroscopic measurement by the spectroscope 20 is narrowed, and a state in which the measurement angle θ is narrow and the directivity is high can be realized.

  The spectroscope 20 acquires the spectrum of the light that has passed through the light incident slit 21 among the light that has arrived from the measurement object Sa. The spectroscope 20 has sensitivity in the band of light output from the light source 10. The spectral band that can be dispersed by the spectroscope 20 is preferably included in the wavelength band of white light output from the light source 10. The spectroscope 20 acquires the first spectrum during a period in which the light output from the light source 10 is applied to the measurement object Sa, and in a period in which the light output from the light source 10 is not applied to the measurement object Sa. A second spectrum is acquired.

  As the spectroscope 20, for example, a micro spectroscope C12666MA or C12880MA manufactured by Hamamatsu Photonics Co., Ltd. is preferably used. These micro-spectrometers integrate a light entrance slit, a grating and a CMOS linear image sensor using MOEMS (Micro Opto Electro Mechanical Systems) technology, and the size is W20.1 x D12.5 x H10.1 mm. Therefore, it is suitable for configuring the non-contact spectrometer 1A having portability.

  The beam splitter 52 is provided in the middle of the optical path from the second polarizer 42 to the lens 54. The beam splitter 52 divides the light output from the second polarizer 42 into the first branched light and the second branched light, outputs the first branched light to the spectroscope 20, and outputs the second branched light to the imaging unit. Output to 30. The imaging unit 30 receives the second branched light output from the beam splitter 52, images the measurement object Sa, and outputs image data obtained by the imaging. The imaging unit 30 has sensitivity in the band of light output from the light source 10. The imaging unit 30 may be a CCD camera or a CMOS camera.

  The control device 3 is electrically connected to the measurement head 2A. The control device 3 controls the operation of the measurement head 2A (for example, irradiation / non-irradiation of light to the measurement object Sa, spectrum acquisition by the spectroscope 20, and imaging by the imaging unit 30). The control device 3 includes a display unit 3 a that receives image data output from the imaging unit 30 and displays an image of the measurement object Sa captured by the imaging unit 30. Further, the control device 3 is used as a calculation unit that inputs the first spectrum and the second spectrum acquired by the spectroscope 20 and performs a predetermined calculation (described later) based on these spectra. As the control device 3, a personal computer (PC) is used, but it is preferable to use a notebook PC or tablet PC that is small and portable.

  The first polarizer 41 outputs light of specific polarization (linearly polarized light in a specific direction or circularly polarized light in a specific rotation direction) out of broadband white light (generally non-polarized light) output from the light source 10. On the other hand, the 2nd polarizer 42 outputs the light except the light of this specific polarization among the light which a measurement object Sa generated. That is, the second polarizer 42 outputs the specific polarized light reflected from the surface of the measuring object Sa among the light output from the light source 10 and made the specific polarized light by the first polarizer 41 and applied to the measuring object Sa. Selectively block light to be maintained, and selectively block light that maintains specific polarization out of diffusely reflected light (generally non-polarized light) reflecting light absorption inside the measuring object Sa, etc. The light of the polarized component is selectively transmitted. The light output from the second polarizer 42 is light that excludes light of specific polarization from the diffuse reflection light that reflects light absorption inside the measurement object Sa. Such diffuse reflected light is received by the spectroscope 20 and the imaging unit 30, respectively.

  The first polarizer 41 and the second polarizer 42 may be polarizers that output linearly polarized light. In this case, the first polarizer 41 and the second polarizer 42 are arranged such that the polarization directions of the linearly polarized light output from each of the first polarizer 41 and the second polarizer 42 are orthogonal to each other.

  The first polarizer 41 and the second polarizer 42 may be polarizers that output circularly polarized light. In this case, the first polarizer 41 and the second polarizer 42 output circularly polarized light having the same rotational orientation. In general, such a polarizer has a structure in which a linear polarizing filter layer and a quarter-wave plate layer are laminated. The linear polarization filter layer of the first polarizer 41 and the linear polarization filter layer of the second polarizer 42 may have the same polarization azimuth of the linearly polarized light output from each other. The broadband white light output from the light source 10 passes through the linear polarization filter layer of the first polarizer 41 and enters a specific linear polarization state, and then passes through the quarter wavelength plate layer of the first polarizer 41. Thus, a circularly polarized state of either left rotation or right rotation is obtained. When the circularly polarized light output from the first polarizer 41 is irradiated onto the measurement object Sa, the light reflected on the surface of the measurement target Sa is circularly polarized light having a rotation direction opposite to the irradiation light. Therefore, when linearly polarized light is obtained by the quarter-wave plate layer of the second polarizer 42, it is blocked by the linearly polarizing filter layer of the second polarizer 42. Therefore, the light output from the second polarizer 42 is light that excludes light of a specific polarization from the diffuse reflection light that reflects light absorption inside the measurement object Sa.

  The direction in which the light output from the light source 10 is applied to the measurement object Sa (the direction of the first optical path in the measurement object Sa) and the light generated in the measurement object Sa are transmitted from the measurement object Sa to the spectrometer 20 and the imaging. An angle formed by the direction emitted to the unit 30 (the direction of the second optical path in the measurement object Sa) is α. This angle α is preferably variable. By appropriately adjusting the angle α according to the distance to the measurement object Sa, the range (irradiation range Ra) in which the light from the light source 10 is irradiated on the measurement object Sa is the light reception range and imaging of the spectrometer 20. It can be set to overlap the imaging range of the unit 30.

  It is preferable that the range (irradiation range Ra) in which the measurement object Sa is irradiated with light from the light source 10 through the first optical path has a visible spot shape. In addition, the narrower the irradiation range Ra, the better. Therefore, it is preferable to use an irradiation optical system that forms an irradiation range Ra having a clear outline by using a light source 10 whose output light includes visible light and can be regarded as a point light source as much as possible. .

  In addition to displaying the image of the measuring object Sa imaged by the imaging unit 30, the display unit 3 a of the control device 3 includes a range in which the spectroscope 20 performs spectroscopic measurement in the image of the measuring object Sa (spectral is possible). It is preferred to display the range Rb). By doing in this way, it becomes easy to carry out the spectroscopic measurement of the desired range in the measuring object Sa.

  Next, a non-contact spectrometer 1B according to the second embodiment will be described. FIG. 3 is a diagram illustrating a configuration of a non-contact spectrometer 1B according to the second embodiment. The non-contact spectrometer 1B includes a measurement head 2B and a control device 3. The measurement head 2B includes a light source 10, a spectrometer 20, a first polarizer 41, a second polarizer 42, a shutter 51, a beam splitter 52, a lens 54, a diaphragm 55, and a beam damper 56. In the following, differences from the configuration of the non-contact spectrometer 1A of the first embodiment will be mainly described.

  In the measurement head 2B in the second embodiment, the first optical path from the light source 10 to the measurement object Sa and the second optical path from the measurement object Sa to the spectroscope 20 allow light to enter the measurement object Sa. The exiting portion (the portion of the optical path between the measuring object Sa and the beam splitter 52) is a common optical path.

  The first polarizer 41 and the shutter 51 are disposed on the optical path between the light source 10 and the beam splitter 52. The second polarizer 42 is disposed on the optical path between the beam splitter 52 and the lens 54. The first polarizer 41 and the second polarizer 42 may be polarizers that output linearly polarized light, or may be polarizers that output circularly polarized light.

  The broadband white light output from the light source 10 is made specific polarization by the first polarizer 41, passes through the shutter 51, and is input to the beam splitter 52. The light input from the light source 10 to the beam splitter 52 passes through the beam splitter 52 and is irradiated onto the measurement object Sa. At this time, a part of the light input from the light source 10 to the beam splitter 52 is reflected by the beam splitter 52, but the reflected light is absorbed by the beam damper 56. Further, the light generated by the measuring object Sa is reflected by the beam splitter 52 and output to the spectrometer 20.

  In the non-contact spectroscopic measurement apparatus 1B of the second embodiment, since the part where light enters and exits the measurement object Sa in the first optical path and the second optical path is a common optical path, up to the measurement object Sa. Even if the distance changes, the irradiation range Ra can be formed with spot illumination having a clear outline, and one point or a partial range within the range can be reliably subjected to spectroscopic measurement.

  Next, a non-contact spectrometer 1C of the third embodiment will be described. FIG. 4 is a diagram illustrating a configuration of a non-contact spectrometer 1C according to the third embodiment. The non-contact spectrometer 1C includes a measurement head 2C and a control device 3. The measurement head 2C in the third embodiment shown in FIG. 4 further includes a beam splitter 53, a beam damper 57, and an imaging unit 30 in addition to the configuration of the measurement head 2B in the second embodiment shown in FIG. Below, the point which is different from the structure of the non-contact spectrometry apparatus 1B of 2nd Embodiment is mainly demonstrated.

  In the measurement head 2 </ b> C in the third embodiment, a beam splitter 53 is also provided in addition to the beam splitter 52. The beam splitter 53 is disposed on the optical path between the first polarizer 41 and the shutter 51 and the beam splitter 52.

  The first polarizer 41 and the shutter 51 are disposed on the optical path between the light source 10 and the beam splitter 53. The second polarizer 42 is disposed on the optical path between the beam splitter 52 and the lens 54. The first polarizer 41 and the second polarizer 42 may be polarizers that output linearly polarized light, or may be polarizers that output circularly polarized light.

  The broadband white light output from the light source 10 is made specific polarization by the first polarizer 41, passes through the shutter 51, and is input to the beam splitter 53. Light input from the light source 10 to the beam splitter 53 passes through the beam splitter 53 and is output to the beam splitter 52. At this time, part of the light input from the light source 10 to the beam splitter 53 is reflected by the beam splitter 53, but the reflected light is absorbed by the beam damper 57.

  The light input from the beam splitter 53 to the beam splitter 52 passes through the beam splitter 52 and is irradiated onto the measurement object Sa. A part of the light input from the beam splitter 53 to the beam splitter 52 is reflected by the beam splitter 52, and the reflected light is absorbed by the beam damper 56.

  A part of the light generated by the measuring object Sa is reflected by the beam splitter 52 and output to the spectroscope 20, and the remaining part is transmitted through the beam splitter 52 and output to the beam splitter 53. Light input from the beam splitter 52 to the beam splitter 53 is reflected by the beam splitter 53 and output to the imaging unit 30.

  The non-contact spectroscopic measurement apparatus 1C of the third embodiment also has a common optical path where light enters and exits the measurement object Sa in the first optical path and the second optical path. Even if the distance changes, the irradiation range Ra can be formed with spot illumination having a clear outline, and one point or a partial range within the range can be reliably subjected to spectroscopic measurement. Further, the non-contact spectroscopic measurement apparatus 1C of the third embodiment includes the imaging unit 30 and the display unit 3a, so that an image of the measurement object Sa can be displayed, and the spectroscopic range Rb is displayed in the image. Can be displayed.

  Next, a non-contact spectrometer 1D according to the fourth embodiment will be described. FIG. 5 is a diagram illustrating a configuration of a non-contact spectrometer 1D according to the fourth embodiment. The non-contact spectrometer 1D includes a measurement head 2D and a control device 3. The measurement head 2D in the fourth embodiment shown in FIG. 5 is polarized in place of the first polarizer 41 and the second polarizer 42 as compared with the configuration of the measurement head 2B in the second embodiment shown in FIG. The difference is that a child 40 is provided. Below, the point which is different from the structure of the non-contact spectrometry apparatus 1B of 2nd Embodiment is mainly demonstrated.

  In the measuring head 2D in the fourth embodiment, the first optical path from the light source 10 to the measuring object Sa and the second optical path from the measuring object Sa to the spectroscope 20 allow light to enter the measuring object Sa. The exiting portion (the portion of the optical path between the measuring object Sa and the beam splitter 52) is a common optical path. The polarizer 40 is a polarizer that outputs circularly polarized light. The polarizer 40 serves as both the first polarizer 41 and the second polarizer 42, and is disposed in the common optical path.

  The broadband white light output from the light source 10 passes through the shutter 51 and is input to the beam splitter 52. The light input from the light source 10 to the beam splitter 52 is transmitted through the beam splitter 52, converted into a specific circularly polarized light by the polarizer 40, and irradiated onto the measurement object Sa. At this time, a part of the light input from the light source 10 to the beam splitter 52 is reflected by the beam splitter 52, but the reflected light is absorbed by the beam damper 56. Further, the light generated by the measuring object Sa is reflected by the beam splitter 52 and output to the spectroscope 20 after the specific circularly polarized light is removed by the polarizer 40.

  Next, a non-contact spectrometer 1E according to the fifth embodiment will be described. FIG. 6 is a diagram showing a configuration of a non-contact spectrometer 1E according to the fifth embodiment. The non-contact spectrometer 1E includes a measurement head 2E and a control device 3. The measurement head 2E in the fifth embodiment shown in FIG. 6 is polarized in place of the first polarizer 41 and the second polarizer 42 as compared with the configuration of the measurement head 2C in the third embodiment shown in FIG. The difference is that a child 40 is provided. In the following, differences from the configuration of the non-contact spectrometer 1C of the third embodiment will be mainly described.

  In the measurement head 2E in the fifth embodiment, the first optical path from the light source 10 to the measurement object Sa and the second optical path from the measurement object Sa to the spectroscope 20 allow light to enter the measurement object Sa. The exiting portion (the portion of the optical path between the measuring object Sa and the beam splitter 52) is a common optical path. The polarizer 40 is a polarizer that outputs circularly polarized light. The polarizer 40 serves as both the first polarizer 41 and the second polarizer 42, and is disposed in the common optical path.

  The broadband white light output from the light source 10 passes through the shutter 51 and is input to the beam splitter 53. Light input from the light source 10 to the beam splitter 53 passes through the beam splitter 53 and is output to the beam splitter 52. At this time, part of the light input from the light source 10 to the beam splitter 53 is reflected by the beam splitter 53, but the reflected light is absorbed by the beam damper 57.

  The light input from the beam splitter 53 to the beam splitter 52 is transmitted through the beam splitter 52, converted into a specific circularly polarized light by the polarizer 40, and irradiated onto the measurement object Sa. A part of the light input from the beam splitter 53 to the beam splitter 52 is reflected by the beam splitter 52, and the reflected light is absorbed by the beam damper 56.

  After the specific circularly polarized light is removed by the polarizer 40, a part of the light generated from the measurement object Sa is reflected by the beam splitter 52 and output to the spectrometer 20, and the remaining part is transmitted through the beam splitter 52. And output to the beam splitter 53. Light input from the beam splitter 52 to the beam splitter 53 is reflected by the beam splitter 53 and output to the imaging unit 30.

  Next, a non-contact spectrometer 1F of the sixth embodiment will be described. FIG. 32 is a diagram illustrating a configuration of a non-contact spectrometer 1F according to the sixth embodiment. The non-contact spectrometer 1F includes a measurement head 2F and a control device 3. The measurement head 2F in the sixth embodiment shown in FIG. 32 is optically coupled between the light source 10, the spectroscope 20, and the imaging unit 30 as compared with the configuration of the measurement head 2C in the third embodiment shown in FIG. It differs in the point of arrangement relation. In the following, differences from the configuration of the non-contact spectrometer 1C of the third embodiment will be mainly described.

  In the measurement head 2F in the sixth embodiment, beam splitters 52 and 53 are provided in the optical path between the imaging unit 30 and the measurement object Sa. The beam splitter 52 provided at a position near the measurement object Sa among the beam splitters 52 and 53 reflects the light output from the light source 10 and transmitted through the first polarizer 41 toward the measurement object Sa, Further, the light reaching from the measuring object Sa is transmitted toward the second polarizer 42. The beam splitter 53 provided at a position close to the imaging unit 30 among the beam splitters 52 and 53 splits the light that has arrived from the beam splitter 52 via the second polarizer 42 into two, and splits one split light into a spectroscope. 20, and the other branched light is output to the imaging unit 30.

  The broadband white light output from the light source 10 is made specific polarization by the first polarizer 41, passes through the shutter 51, and is input to the beam splitter 52. The light input from the light source 10 to the beam splitter 52 is reflected by the beam splitter 52 and applied to the measurement object Sa. At this time, part of the light input from the light source 10 to the beam splitter 52 passes through the beam splitter 52, but the transmitted light is absorbed by the beam damper 56.

  Light generated by the measurement object Sa and input to the beam splitter 52 is input to the beam splitter 53 via the beam splitter 52 and the second polarizer 42. A part of the light input from the measurement object Sa to the beam splitter 53 is reflected by the beam splitter 53 and output to the spectrometer 20, and the remaining part is transmitted through the beam splitter 53 and output to the imaging unit 30.

  In the sixth embodiment, since there is only one beam splitter that passes through the light output from the light source 10 before being irradiated onto the measurement object Sa, the attenuation of light until the measurement object Sa is irradiated is reduced. Can be small. Therefore, the light source 10 with a low light quantity can be used, and the power consumption of the apparatus can be reduced, the size can be reduced, and the portability can be improved.

  Next, a non-contact spectrometer 1G of the seventh embodiment will be described. FIG. 33 is a diagram showing a configuration of a non-contact spectrometer 1G of the seventh embodiment. The non-contact spectrometer 1G includes a measurement head 2G and a control device 3. The measurement head 2G in the seventh embodiment shown in FIG. 33 is polarized in place of the first polarizer 41 and the second polarizer 42 as compared with the configuration of the measurement head 2F in the sixth embodiment shown in FIG. The difference is that a child 40 is provided. In the following, differences from the configuration of the non-contact spectrometer 1F of the sixth embodiment will be mainly described.

  In the measurement head 2G in the seventh embodiment, the polarizer 40 is disposed on the optical path between the beam splitter 52 and the measurement object Sa. The polarizer 40 is a polarizer that outputs circularly polarized light, and serves as both the first polarizer 41 and the second polarizer 42.

  The broadband white light output from the light source 10 passes through the shutter 51 and is input to the beam splitter 52. The light input from the light source 10 to the beam splitter 52 is reflected by the beam splitter 52, converted into a specific circularly polarized light by the polarizer 40, and irradiated onto the measurement object Sa. A part of the light input from the light source 10 to the beam splitter 52 passes through the beam splitter 52, but the transmitted light is absorbed by the beam damper 56.

  The light generated by the measuring object Sa is input to the beam splitter 53 via the beam splitter 52 after the specific circularly polarized light is removed by the polarizer 40. A part of the light input from the measurement object Sa to the beam splitter 53 is reflected by the beam splitter 53 and output to the spectrometer 20, and the remaining part is transmitted through the beam splitter 53 and output to the imaging unit 30.

  Also in the seventh embodiment, since only one beam splitter passes until the light output from the light source 10 is irradiated onto the measurement object Sa, the attenuation of the light until the measurement object Sa is irradiated is reduced. Can be small. Therefore, the light source 10 with a low light quantity can be used, and the power consumption of the apparatus can be reduced, the size can be reduced, and the portability can be improved.

  Next, a non-contact spectrometer 1H of the eighth embodiment will be described. FIG. 34 is a diagram showing a configuration of a non-contact spectrometer 1H of the eighth embodiment. The non-contact spectroscopic measurement apparatus 1H includes a measurement head 2H and a control device 3. The measurement head 2H in the eighth embodiment shown in FIG. 34 is different from the configuration of the measurement head 2F in the sixth embodiment shown in FIG. 32 in terms of the arrangement of the spectrometer 20 and the imaging unit 30 with respect to the beam splitter 53. Is different. In the following, differences from the configuration of the non-contact spectrometer 1F of the sixth embodiment will be mainly described.

  In the measurement head 2F in the sixth embodiment, a part of the light input from the measurement object Sa to the beam splitter 53 is reflected by the beam splitter 53 and output to the spectrometer 20, and the remaining part is transmitted through the beam splitter 53. The image is output to the imaging unit 30. On the other hand, in the measuring head 2H in the eighth embodiment, a part of the light input from the measuring object Sa to the beam splitter 53 is reflected by the beam splitter 53 and output to the imaging unit 30, and the remaining part is the beam splitter. 53 is transmitted to the spectroscope 20. The lens 54 and the diaphragm 55 are provided between the beam splitter 53 and the spectrometer 20.

  The non-contact spectrometer 1H according to the eighth embodiment configured as described above also has the same effect as the non-contact spectrometer 1F according to the sixth embodiment. Also in the configurations of the first embodiment (FIG. 1) and the seventh embodiment (FIG. 33), it is possible to change the arrangement of the spectrometer 20 and the imaging unit 30 with respect to the beam splitter.

  Next, a non-contact spectrometer 1I according to the ninth embodiment will be described. FIG. 35 is a diagram illustrating a configuration of a non-contact spectrometer 1I according to the ninth embodiment. The non-contact spectroscopic measurement device 1I includes a measurement head 2I and a control device 3. The measurement head 2I in the ninth embodiment shown in FIG. 35 is different from the measurement head 2F in the sixth embodiment shown in FIG. 32 in that a laser light source 60 is provided instead of the imaging unit 30. The difference is that a beam damper 57 is further provided. In the following, differences from the configuration of the non-contact spectrometer 1F of the sixth embodiment will be mainly described.

  The laser light source 60 outputs laser light. The laser light source 60 is preferably a laser diode in terms of miniaturization and improved portability. The wavelength of the laser beam is in the visible range, and is appropriately selected according to the color of the measurement object Sa. For example, if the measurement object Sa is green, the wavelength of the laser light is preferably red (for example, 635 nm).

  A part of the light input to the beam splitter 53 along the second optical path from the measurement object Sa is reflected by the beam splitter 53 and output to the spectrometer 20. A part of the laser light input from the laser light source 60 to the beam splitter 53 passes through the beam splitter 53 and is output to the measuring object Sa along the second optical path, and the remaining part is reflected by the beam splitter 53 to be a beam damper 57. Is absorbed by.

  The irradiation position of the laser beam on the measuring object Sa indicates a position or range where spectroscopic measurement is possible. That is, the laser light source 60 is used as a laser pointer indicating a position or range where spectroscopic measurement is possible. This facilitates confirmation of the irradiation range or the spectroscopic range of the measuring object Sa.

  In the configurations of the first embodiment (FIG. 1), the third embodiment (FIG. 4), the fifth embodiment (FIG. 6), the seventh embodiment (FIG. 33), and the eighth embodiment (FIG. 34). Instead of the imaging unit 30, a laser light source 60 can be used. In addition, the arrangement of the spectrometer 20 and the laser light source 60 with respect to the beam splitter can be changed.

  Next, the operation of the non-contact spectroscopic measurement apparatus of the present embodiment will be described, and the non-contact spectroscopic measurement method of the present embodiment will be described with reference to FIGS. The following description of the operation can be applied to any of the non-contact spectrometers according to the first to ninth embodiments.

  7 and 8 are flowcharts for explaining the non-contact spectroscopic measurement method of this embodiment. FIG. 7 is a flowchart of the main routine. FIG. 8 is a flowchart of a subroutine. 9 to 14 are diagrams schematically showing various spectra. FIG. 9 is a diagram schematically showing the output light spectrum Sp0 of the light source 10. As shown in FIG. FIG. 10 is a diagram schematically showing the first spectrum Sp1. FIG. 11 is a diagram schematically showing the second spectrum Sp2. FIG. 12 is a diagram schematically illustrating the third spectrum Sp3. FIG. 13 is a diagram schematically illustrating the fourth spectrum Sp4. FIG. 14 is a diagram schematically showing the fifth spectrum Sp5.

  As shown in FIG. 7, first, when the output light spectrum Sp0 of the light source 10 has not yet been acquired (No in Step St1), the output light spectrum Sp0 (FIG. 9) of the light source 10 is acquired (Step St2). ). If the evaluation calculation formula has not yet been acquired (No in step St3), the evaluation calculation formula is acquired (step St4). The evaluation calculation formula represents a correlation between a relative reflection spectrum Sp5 (described later) and an evaluation value, and is used when the measurement object is evaluated based on the relative reflection spectrum Sp5.

  If the output light spectrum Sp0 of the light source 10 and the calculation formula for evaluation can be prepared, the relative reflection spectrum Sp5 is acquired for each measurement object (step St5), and based on the acquired relative reflection spectrum Sp5 and the calculation formula for evaluation. The measurement object is evaluated (evaluation step St6). The measurement object and evaluation items are, for example, plant chlorophyll concentration, fruit sugar content, rice taste, beef fat, fish fat, feed nutritional component, building material content, and the like. A detailed procedure for obtaining the relative reflection spectrum Sp5 (step St5) is shown in FIG.

  When the laser light source 60 as a laser pointer is provided as in the configuration of the ninth embodiment (FIG. 35), the light source 10 and the laser are switched from the state where both the light source 10 and the laser light source 60 are off. Both the light sources 60 are turned on, the irradiation range or the spectroscopic range on the measuring object Sa is confirmed and set to a desired range. Thereafter, the laser light source 60 is turned off and the process shown in FIG. 8 is performed.

  As shown in FIG. 8, the first spectrum Sp1 is acquired (step St11) and the second spectrum Sp2 is acquired (step St12). The execution order of these two steps St11 and St12 is arbitrary. Step St11 and step St12 are alternately repeated, and the average of the spectra obtained in each of the plurality of steps St11 may be set as the first spectrum Sp1, or the average of the spectra obtained in each of the plurality of steps St12 is set as the second spectrum. It is good also as spectrum Sp2. In steps St11 and St12, the spectroscopic measurement conditions (exposure time, sensitivity, etc.) are set to be the same, and the detected amounts of ambient light and dark signals included in the first spectrum Sp1 and the second spectrum Sp2 are made equal to each other.

  In the first spectrum acquisition step St11, the first polarizer 41 provided in the middle of the first optical path from the light source 10 to the measurement object causes the broadband light output from the light source 10 to be a specific polarization light. Irradiate. During the irradiation period, the second polarizer 42 provided in the middle of the second optical path from the measurement object to the spectrometer 20 removes light of a specific polarization from the light generated in the measurement object. 20 and the spectroscope 20 acquires the spectrum of the incident light (first spectrum Sp1). The first spectrum Sp1 (FIG. 10) is obtained by irradiating the measurement target with the spectrum of diffuse reflected light reflecting light absorption inside the measurement target when the light from the light source 10 is irradiated to the measurement target. As a result, the spectrum of the reflected light generated by the measurement object and the spectrum of the dark signal of the spectroscope 20 are included. Ambient ambient light is, for example, sunlight if it is outdoors, and is, for example, indoor illumination light if it is indoors.

  In the second spectrum acquisition step St <b> 12, the spectrum (second spectrum Sp <b> 2) of the light incident on the spectroscope 20 is acquired by the spectroscope 20 during a period when the measurement object is not irradiated with the light output from the light source 10. The second spectrum Sp2 (FIG. 11) includes a spectrum of reflected light generated by the measurement object as a result of irradiation of ambient environment light on the measurement object and a spectrum of a dark signal of the spectroscope 20. In FIG. 11, the broken line indicates the dark signal spectrum of the spectroscope 20.

  The control device 3 inputs the first spectrum Sp1 and the second spectrum Sp2 as described above from the spectroscope 20, and performs the following calculation processing (steps St13 to St15, St6) as a calculation unit.

  In the third spectrum acquisition step (subtraction step) St13, the second spectrum Sp2 is subtracted from the first spectrum Sp1, and the third spectrum Sp3 (= Sp1-Sp2) is obtained as the subtraction result. The third spectrum Sp3 (FIG. 12) obtained by this subtraction is obtained by removing the influence of ambient light and the dark signal of the spectroscope 20, and is measured by irradiating the measurement object with light from the light source 10. It represents the spectrum of diffusely reflected light reflecting light absorption inside the object. By obtaining the third spectrum Sp3 by performing such subtraction, it is possible to remove the influence of ambient ambient light that is different for each measurement, and generally remove the influence of the dark signal of the spectroscope 20 that varies depending on the temperature. be able to.

  In a fourth spectrum acquisition step (division step) St14, the third spectrum Sp3 is divided by the output light spectrum Sp0 of the light source 10, and a fourth spectrum Sp4 (= Sp3 / Sp0) is obtained as a result of the division. A fourth spectrum Sp4 (FIG. 13) obtained by this division represents a reflectance spectrum.

  Normally, when obtaining the reflectance spectrum of a measurement object, place it at the position of the measurement object under the same lighting conditions, including ambient light, before and after obtaining the spectrum of the reflected light from the measurement object. A spectrum of reflected light from a standard white plate or the like is acquired and used as an illumination light spectrum. However, for example, in an outdoor field, the illumination conditions vary greatly depending on the sunshine conditions and the distance from the light source. Therefore, when using a standard white plate, it is necessary to acquire an illumination light spectrum for each measurement. Repeating this work on the field is cumbersome and burdensome. Therefore, in the present embodiment, it is convenient to obtain the output light spectrum Sp0 of the light source 10 in advance and obtain only the reflected light spectrum and calculate the reflected spectrum at a site such as a farm field.

  In the above-described evaluation step St6, the measurement object may be evaluated based on the fourth spectrum Sp4 and the calculation formula for evaluation. However, in this case, there is a high possibility that the distance to the measurement object is different for each measurement, and the irradiation intensity on the measurement object may be different. Therefore, the fourth spectrum Sp4 obtained every measurement is different, and the evaluation of the measurement object based on the fourth spectrum Sp4 may not be an appropriate result. Therefore, in the evaluation step St6, it is preferable to evaluate the measurement object based on the relative reflection spectrum (fifth spectrum) Sp5 obtained in the fifth spectrum acquisition step St15 described below.

In a fifth spectrum acquisition step (standardization step) St15, the fourth spectrum Sp4 is standardized to obtain a fifth spectrum Sp5 (FIG. 14). There are various standardization processing methods. Among these, standardization processing by SNV correction (Standard Normal Variate Correction) is as follows. The fourth spectrum Sp4 is expressed as I (λ) as a function of the wavelength λ, the average value of I (λ) in a certain wavelength range is I _ave, and the standard deviation is I _stddev . 'Expressed as (λ), I' I the fifth spectral Sp5 as a function of the wavelength λ (λ) = {I ( λ) -I ave} represented by / I _stddev becomes equation. This I ′ (λ) is a dimensionless quantity.

  As described above, in the present embodiment, the first polarizer 41 is provided in the middle of the first optical path from the light source 10 to the measurement object, and the second polarization is in the middle of the second optical path from the measurement object to the spectrometer 20. A child 42 is provided. Then, the first polarizer 41 and the second polarizer 42 selectively receive the diffuse reflected light reflecting the light absorption in the measurement object, and the spectrum of the diffuse reflected light is spectrally separated. Acquired by the vessel 20. Therefore, the degree of freedom in setting the optical system between the non-contact spectroscopic measurement apparatus and the measurement object is high, and it is easy to appropriately evaluate the measurement object.

  In the present embodiment, an irradiation range Ra having a clear outline on the measurement object is formed by the irradiation optical system. Alternatively, the spectroscopic range Rb is displayed in the image of the measurement object by the imaging unit and the display unit. Thereby, since it is easy to confirm the irradiation range Ra or the spectroscopic range Rb in the measurement target, even in a field such as a field where it is difficult to stabilize the optical axis, It becomes easy to stably acquire the spectrum of the diffuse reflected light.

  Moreover, in this embodiment, it is possible to acquire the reflected light spectrum from the measurement object in a non-destructive and non-contact manner. By analyzing the acquired reflected light spectrum, the measurement object can be evaluated without causing destruction and infection with pathogenic bacteria. For example, various plant growth indexes such as SPAD values representing chlorophyll concentration can be obtained, which can contribute to growth management and clarification of harvest criteria.

  In the example described below, the SPAD value of Komatsuna as a measurement object is evaluated using the non-contact spectroscopic measurement apparatus 1A of the first embodiment shown in FIG. It compared with the measurement result by (SPAD-502 by Konica Minolta Co., Ltd.). In addition, this SPAD meter can measure the chlorophyll concentration of a measurement object by measuring the absorption rate of a plurality of wavelengths with a measurement object sandwiched between a light source unit and a detection unit. Since this SPAD meter contacts the measurement object during measurement, there is a risk of contamination of the measurement object (mediation of pathogenic bacteria, etc.).

  An object to be measured (Komatsuna) was placed on a work table in the laboratory, and a non-contact spectroscopic measurement device was placed above the work table. Ambient ambient light was mainly indoor lighting. The first optical path from the light source 10 to the measurement object was set vertically above the measurement object. The second optical path from the measurement object to the spectroscope 20 was 45 ° upward from the horizontal direction. A halogen lamp was used as the light source 10. Since the irradiation light band of 700 nm or more is necessary to obtain the SPAD value, a halogen lamp from which the infrared cut filter was removed was used. As the spectrometer 20, a micro spectrometer C12666MA manufactured by Hamamatsu Photonics Co., Ltd. was used. The size of the light entrance slit of this spectroscope is 50 μm in the vertical direction × 750 μm in the horizontal direction. A small CMOS camera module was used as the imaging unit 30. As the first polarizer 41 and the second polarizer 42, polarizers that output circularly polarized light were used.

  The white light output from the light source 10 was guided by a light guide, passed through the aperture, and irradiated to a spot shape having a clear outline on the measurement object. Moreover, the area | region illuminated in spot shape in the measuring object was imaged by the imaging part 30, and was displayed by the display part 3a. Further, the display unit 3a displayed a circle around the intersection of the cross line at the center of the screen as a range (spectral range Rb) that the spectroscope 20 performs spectroscopic measurement in the image of the measurement object. FIG. 15 is a graph showing the directivity in the vertical direction in the spectrometer 20. FIG. 16 is a graph showing the directivity in the horizontal direction in the spectrometer 20. In both figures, the horizontal axis is the angle from the optical axis of the spectrometer, and the vertical axis is the relative sensitivity. The half-value angle in the vertical direction was about 0.5 °, and the half-value angle in the horizontal direction was about 1.2 °. Therefore, the angle range of 2 ° with the optical axis of the spectroscope being roughly estimated was displayed in a circle as the spectroscopic range Rb.

  If the spectroscopic range Rb on the display unit 3a is used, it is possible to perform spectroscopic measurement while avoiding a foreign object on the measurement object or a non-target part (such as a vein), which can contribute to improvement in measurement accuracy. It is expected that the irradiation range Ra of the embodiment without the display unit (FIGS. 3 and 5) also has a similar contribution. On the other hand, a commercially available SPAD meter used with the measurement object sandwiched between has a problem in that it is difficult to confirm the position because the measurement site is hidden.

  By appropriately selecting the focal length of the lens 54 and the aperture diameter of the aperture 55, the hyperfocal distance is set to 250 mm, and all the measurement objects located at a distance of 125 mm or more from the lens 54 are connected to the rear focal position of the lens 54. I tried to image. Therefore, in the present embodiment, the first spectrum Sp1 and the second spectrum Sp2 can be obtained without focusing if the measurement object is 125 mm or more away from the lens 54.

  FIG. 17 is a diagram illustrating the first spectrum Sp1 acquired in the first spectrum acquisition step St11. FIG. 18 is a diagram illustrating the second spectrum Sp2 acquired in the second spectrum acquisition step St12. FIG. 19 is a diagram illustrating the third spectrum Sp3 acquired in the third spectrum acquisition step St13. The third spectrum Sp3 (= Sp1-Sp2) is obtained by removing the influence of ambient light and the dark signal of the spectroscope 20, and the light from the light source 10 is irradiated onto the measurement object, and the measurement object. It represents the spectrum of diffusely reflected light reflecting the internal light absorption. Note that these spectra Sp1, Sp2, Sp3 are raw data from the spectroscope 20 and are not subjected to wavelength sensitivity correction. However, the third spectrum Sp3 is the output light spectrum Sp0 that is still raw data in the same manner. There is no problem because it divides.

  FIG. 20 is a diagram illustrating the output light spectrum Sp0 and the third spectrum Sp3 of the light source 10. FIG. 21 is a diagram illustrating the fourth spectrum Sp4 acquired in the fourth spectrum acquisition step St14. The fourth spectrum Sp4 (= Sp3 / Sp0) represents the reflectance spectrum. Note that, in the wavelength band of approximately 400 nm or less, the intensity of the output light spectrum Sp0 is small, and therefore the noise of the fourth spectrum Sp4 is large. In the wavelength band of approximately 500 nm or less, the intensity of the third spectrum Sp3 is small and the intensity of the fourth spectrum Sp4 is also small. Therefore, hereinafter, a band having a wavelength of 500 nm or more will be handled.

  FIG. 22 is a diagram illustrating the fourth spectrum Sp4 acquired in the fourth spectrum acquisition step St14 using each of the 16 Komatsuna leaves as the measurement object. FIG. 23 is a diagram illustrating the fifth spectrum Sp5 acquired in the fifth spectrum acquisition step St15 using each of the 16 Komatsuna leaves as the measurement object. Visually, the green density of these 16 Komatsuna leaves varied. Moreover, the SPAD value of these 16 Komatsuna leaves was measured with a commercially available SPAD meter.

  As shown in FIG. 22, the fourth spectrum Sp4 acquired for each of the 16 Komatsuna leaves appears to have large variations and is difficult to handle. However, as shown in FIG. 23, the relative reflection spectrum (fifth spectrum) Sp5 obtained by performing the SNV correction process on the fourth spectrum Sp4 is reduced in variation among the 16 Komatsuna leaves. ing.

  The correlation between the fifth spectrum Sp5 of each of the 16 Komatsuna leaves and the measurement result by a commercially available SPAD meter was evaluated. As a result, it was found that the respective intensities of the wavelengths 547 nm and 718 nm in the fifth spectrum Sp5 have a high correlation with the measurement result by the SPAD meter. Therefore, multiple regression analysis was performed using the intensity values of the fifth spectrum Sp5 near the wavelengths of 547 nm and 718 nm to estimate the SPAD value.

  FIG. 24 is a graph showing the correlation between the SPAD estimated value based on the fifth spectrum Sp5 and the SPAD actual measurement value by the SPAD meter. This figure shows the positions representing the estimated SPAD value and the measured SPAD value for each of the 16 Komatsuna leaves. The prediction error of cross validation was 2.18, which was a good result.

Further, from the results of this multiple regression analysis, assuming that the relative reflectance at the wavelength 547 nm is R1 and the relative reflectance at the wavelength 718 nm is R2 in the relative reflectance spectrum (fifth spectrum) Sp5, the SPAD estimated value in this experimental example The calculation formula is as follows.
SPAD estimate = 6.8139 x R1 + 13.6028 x R2 + 20.8201
If the reflection spectrum of an individual plant sample is acquired in the field, the corresponding SPAD value can be acquired sequentially by using this calculation formula in the evaluation step St6. Correlation evaluation and multiple regression analysis were performed using multivariate analysis software “The Unscrambler X”.

  As described above, according to the present embodiment, a result equivalent to that of a conventional SPAD meter can be obtained without contact.

  Next, each spectrum was acquired when ambient ambient light was set in various ways. A fluorescent lamp, a xenon lamp, or a red lamp was used as a light source of ambient ambient light. In any case, a common light source 10 was used, and a common measurement object (Komatsuna) was used. FIG. 25 is a diagram illustrating spectra Sp1 to Sp3 when a fluorescent lamp is used as the ambient environment light source. FIG. 26 is a diagram illustrating spectra Sp1 to Sp3 when a xenon lamp is used as the ambient environment light source. FIG. 27 is a diagram showing spectra Sp1 to Sp3 when a red lamp is used as the ambient environment light source. The first spectrum Sp1 is a spectrum acquired by the spectroscope 20 when the measurement object is irradiated by both the light source 10 and the ambient environment light source. The second spectrum Sp2 is a spectrum acquired by the spectroscope 20 when the measurement object is irradiated only by the ambient environment light source. The third spectrum Sp3 is a spectrum obtained by subtracting the second spectrum Sp2 from the first spectrum Sp1.

  FIG. 28 is a diagram illustrating a third spectrum Sp3 when a fluorescent lamp, a xenon lamp, and a red lamp are used as ambient environment light sources. FIG. 29 is a diagram showing a spectrum obtained by performing standardization processing by SNV correction on the third spectrum Sp3 when each of the fluorescent lamp, the xenon lamp, and the red lamp is used as the ambient environment light source. As shown in FIG. 28, it can be seen that the third spectrum Sp3 before the standardization process is different when the ambient light is different depending on the measurement opportunity. On the other hand, as shown in FIG. 29, it can be seen that the spectra obtained by standardizing the third spectrum Sp3 have substantially the same shape even if the ambient light is different. That is, it can be seen that the spectra obtained by the standardization process are similar, and may be treated as the same when compared by relative intensity.

  FIG. 30 is a diagram illustrating a second spectrum Sp2 when a fluorescent lamp, a xenon lamp, and a red lamp are used as ambient environment light sources. FIG. 31 is a diagram illustrating a spectrum obtained by performing standardization processing by SNV correction on the second spectrum Sp2 when a fluorescent lamp, a xenon lamp, and a red lamp are used as the ambient environment light sources. As shown in these figures, when the ambient light varies depending on the measurement opportunity, not only the second spectrum Sp2 before the standardization process is different, but also the spectrum obtained by performing the standardization process on the second spectrum Sp2. I can see that they are different.

  Therefore, in order to obtain the spectrum of the reflected light from the measurement object, it is necessary to spectroscopically measure the reflected light from a white scattering plate or the like disposed in the vicinity of the measurement object to obtain the ambient light spectrum. . Further, it is necessary to acquire the ambient light spectrum at every measurement opportunity. Repeating this work on the field in a complicated manner is labor intensive. However, in this embodiment, the apparatus includes a white light source, and the reflected light spectrum (third spectrum) Sp3 is obtained by subtracting the second spectrum Sp2 from the first spectrum Sp1, and this third spectrum Sp3 is obtained from the white light source. Since the reflectance spectrum (fourth spectrum) Sp4 is obtained by dividing by the output light spectrum Sp0, the measurement object can be easily evaluated.

  DESCRIPTION OF SYMBOLS 1A-1I ... Non-contact spectroscopic measurement apparatus, 2A-2I ... Measuring head, 3 ... Control apparatus (calculation part), 3a ... Display part, 10 ... Light source, 20 ... Spectroscope, 30 ... Imaging part, 40 ... Polarizer, DESCRIPTION OF SYMBOLS 41 ... 1st polarizer, 42 ... 2nd polarizer, 51 ... Shutter, 52, 53 ... Beam splitter, 54 ... Lens, 55 ... Aperture, 56, 57 ... Beam damper, 60 ... Laser light source, Ra ... Irradiation range, Rb ... spectral range, Sa, Sb ... object to be measured.

Claims (20)

A light source that outputs broadband light;
A first polarizer that is provided in the middle of a first optical path from the light source to the measurement object, inputs light output from the light source, and outputs light of specific polarization to the measurement object;
A spectroscope for acquiring a spectrum of light that has reached among the light generated by the measurement object;
Second polarized light that is provided in the middle of the second optical path from the measurement object to the spectrometer, inputs light generated by the measurement object, and outputs light other than the light of the specific polarization to the spectrometer. With the child,
From the first spectrum acquired by the spectrometer during the period when the measurement object is irradiated with the light output from the light source, the period when the measurement object is not irradiated with the light output from the light source. Subtracting the second spectrum acquired by the spectroscope, obtaining a third spectrum as the subtraction result, obtaining a fourth spectrum as a result of dividing the third spectrum by the output light spectrum of the light source, A computing unit that evaluates the measurement object based on a fifth spectrum obtained by processing the fourth spectrum;
A non-contact spectroscopic measurement apparatus. The computing unit obtains a fifth spectrum by standardizing the fourth spectrum, and evaluates the measurement object based on the fifth spectrum.
The non-contact spectroscopic measurement apparatus according to claim 1. The first optical path and the second optical path are common optical paths where light enters and exits the measurement object.
The non-contact spectrometry apparatus according to claim 1 or 2. The first polarizer and the second polarizer are polarizers that output linearly polarized light,
The non-contact spectrometry apparatus according to any one of claims 1 to 3. The first polarizer and the second polarizer are polarizers that output circularly polarized light,
The non-contact spectrometry apparatus according to any one of claims 1 to 3. The first polarizer and the second polarizer are polarizers that output circularly polarized light, and are provided as a common polarizer in the middle of the common optical path.
The non-contact spectroscopic measurement apparatus according to claim 3. A beam splitter provided in the middle of the second optical path, bifurcating light from the measurement object into first branched light and second branched light, and outputting the first branched light to the spectrometer;
An imaging unit that receives the second branched light output from the beam splitter and images the measurement object;
A display unit for displaying an image of the measurement object imaged by the imaging unit;
The non-contact spectrometry apparatus according to claim 1, further comprising: The display unit displays a range in which the spectroscope performs spectroscopic measurement in the image of the measurement object.
The non-contact spectroscopic measurement apparatus according to claim 7. A laser light source for outputting laser light;
A beam splitter provided in the middle of the second optical path for outputting light from the measurement object to the spectrometer and outputting laser light from the laser light source to the measurement object along the second optical path. When,
The non-contact spectrometry apparatus according to claim 1, further comprising: The range in which the measurement object is irradiated with light through the first optical path is a visible spot shape.
The non-contact spectrometry apparatus according to any one of claims 1 to 9. With the first polarizer provided in the middle of the first optical path from the light source to the measurement object, the measurement object is irradiated with the broadband light output from the light source as light of a specific polarization, and during the irradiation period, The second polarizer provided in the middle of the second optical path from the measurement object to the spectroscope makes light excluding the light of the specific polarization out of the light generated by the measurement object enter the spectroscope. A first spectrum acquisition step of acquiring the first spectrum of the incident light by the spectrometer;
A second spectrum acquisition step of acquiring a second spectrum of light incident on the spectroscope by the spectroscope during a period when the measurement object is not irradiated with light output from the light source;
Subtracting a third spectrum as a result of subtracting the second spectrum from the first spectrum;
A division step of obtaining a fourth spectrum as a result of dividing the third spectrum by the output light spectrum of the light source;
An evaluation step of evaluating the measurement object based on the fourth spectrum or a fifth spectrum obtained by processing the fourth spectrum;
A non-contact spectroscopic measurement method comprising: A standardization step of obtaining a fifth spectrum by standardizing the fourth spectrum;
In the evaluation step, the measurement object is evaluated based on the fifth spectrum.
The non-contact spectroscopic measurement method according to claim 11. The first optical path and the second optical path are common optical paths where light enters and exits the measurement object.
The non-contact spectroscopic measurement method according to claim 11 or 12. The first polarizer and the second polarizer are polarizers that output linearly polarized light,
The non-contact spectrometry method according to any one of claims 11 to 13. The first polarizer and the second polarizer are polarizers that output circularly polarized light,
The non-contact spectrometry method according to any one of claims 11 to 13. The first polarizer and the second polarizer are polarizers that output circularly polarized light, and are provided as a common polarizer in the middle of the common optical path.
The non-contact spectroscopic measurement method according to claim 13. A beam splitter provided in the middle of the second optical path splits the light from the object to be measured into a first branched light and a second branched light, and outputs the first branched light to the spectrometer. , Outputting the second branched light to the imaging unit,
The measurement object is imaged by the imaging unit that has received the second branched light,
An image of the measurement object captured by the imaging unit is displayed by a display unit;
The non-contact spectrometry method according to any one of claims 11 to 16. The display unit displays a range in which the spectroscope performs spectroscopic measurement in the image of the measurement object.
The non-contact spectroscopic measurement method according to claim 17. A beam splitter provided in the middle of the second optical path outputs light from the measurement object to the spectrometer and outputs laser light from a laser light source to the measurement object along the second optical path. To
The non-contact spectrometry method according to any one of claims 11 to 18. The range in which the measurement object is irradiated with light through the first optical path is a visible spot shape.
The non-contact spectrometry method according to any one of claims 11 to 19.