JP7105150B2 - Non-contact spectroscopic measurement device and non-contact spectroscopic measurement method - Google Patents

Description

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

By acquiring the spectrum of the 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 this spectrum. There are various objects for such spectroscopic measurement. Non-Patent Document 1 describes that spectroscopic measurement can non-destructively evaluate the sugar content of fruit, the taste of rice, the fat of beef, the fat of fish, the nutritional components of feed, the components contained in building materials, and the like. there is

For example, if the ingredients contained in agricultural products can be evaluated by non-destructive spectroscopic measurement, the quality control of the agricultural products will become easier, and the appropriate harvesting time of the agricultural products can be clarified. improvement and production efficiency improvement are expected. When food is the object of measurement, in addition to non-destructive spectroscopic measurement, non-contact spectroscopic measurement is important to avoid contamination of the object of measurement.

Patent Document 1 describes an invention of an apparatus capable of non-destructive and non-contact spectroscopic measurement. The non-contact spectrophotometer described in this document measures the intensity of sunlight reflected by plants at each of a plurality of specific wavelengths, and measures the intensity of directly incident sunlight to determine the former intensity. The strength of the latter is corrected. Then, this non-contact spectroscopic measurement device evaluates the growth state of plants based on the corrected intensities at each of the plurality of specific wavelengths.

Japanese Patent No. 4243014

Tsutomu Okura, "Near-infrared spectroscopic technology in everyday life", Applied Physics, Vol. 87, No. 1, pp. 6-10 (2018)

However, in the conventional spectroscopic measurement techniques 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 object, and the measurement object is properly set. It is difficult to evaluate Regarding this, Non-Patent Document 1 describes that "the observed spectrum is affected by the arrangement of the sample optical system" and that "refraction, scattering and surface reflection do not reflect material information". Also, it is described that it is important to "select an arrangement that avoids specular reflection" for the optical system.

On the other hand, there is a demand for a non-contact spectroscopic measurement device that is compact, portable, and facilitates on-site spectroscopic measurement. However, since it is not easy to properly set up the optical system between such a non-contact spectroscopic measurement device and the object to be measured, it is even more difficult to properly evaluate the object to be measured.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a non-contact spectroscopic measurement apparatus and a non-contact spectroscopic measurement method that facilitates proper evaluation of an object to be measured.

The non-contact spectroscopic measurement device of the present invention includes (1) a light source that outputs broadband light, and (2) a light source that is provided in the middle of a first optical path from the light source to an object to be measured, and receives the light output from the light source. (3) a spectroscope for obtaining the spectrum of light arriving from the object of measurement; (4) from the object of measurement; a second polarizer provided in the middle of the second optical path leading to the spectroscope, which inputs light generated by the object to be measured and outputs light excluding light of specific polarized light to the spectroscope, and (5) output from the light source. From the first spectrum acquired by the spectroscope while the object to be measured is irradiated with the light emitted from the light source, the second spectrum acquired by the spectroscope while the object to be measured is not irradiated with the light output from the light source. Subtraction results in the third spectrum, division of the third spectrum by the output light spectrum of the light source yields the fourth spectrum, the fourth spectrum or the fifth spectrum obtained by processing the fourth spectrum and a computing unit that evaluates the measurement object based on the spectrum. It is preferable that the calculation unit standardizes the fourth spectrum to obtain a fifth spectrum, and evaluates the measurement object based on this fifth spectrum.

In the non-contact spectroscopic measurement device of the present invention, it is preferable that the first optical path and the second optical path are optical paths having a common portion where light enters and exits the object to be measured. 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. Also, 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 device of the present invention includes: (1) provided in the middle of the second optical path, splitting the light from the object to be measured into first branched light and second branched light, and spectroscopically dispersing the first branched light; (2) an imaging unit that receives the second branched light output from the beam splitter and images an object to be measured; and (3) an image of the object to be measured that is imaged by the imaging unit. It is preferable to further include a display unit that displays It is preferable that the display section displays the range of spectroscopic measurement performed by the spectroscope in the image of the object to be measured. The non-contact spectroscopic measurement apparatus of the present invention includes (1) a laser light source that outputs laser light, and (2) a laser light source that is provided in the middle of a second optical path and outputs light from an object to be measured to a spectroscope. preferably a beam splitter for outputting the laser light from the laser along a second optical path to the object to be measured. 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 first polarizer provided in the middle of a first optical path leading from a light source to an object to be measured measures broadband light output from a light source as light of specific polarized light. The object is irradiated, and during the irradiation period, a second polarizer provided in the middle of the second optical path from the object to be measured to the spectroscope removes light of specific polarization from the light generated by the object to be measured. a first spectrum acquisition step of making light incident on a spectroscope and acquiring a first spectrum of the incident light by the spectroscope; (3) a subtraction step of obtaining a third spectrum as a result of subtracting the second spectrum from the first spectrum; (4) ) dividing the third spectrum by the output light spectrum of the light source to obtain a fourth spectrum; and an evaluation step of evaluating the Preferably, the non-contact spectroscopic measurement method of the present invention further comprises a standardization step of standardizing the fourth spectrum to obtain a fifth spectrum, and evaluating the measurement object based on the fifth spectrum in the evaluation step. be.

In the non-contact spectroscopic measurement method of the present invention, it is preferable that the first optical path and the second optical path are optical paths in which light enters and exits the object to be measured in common. 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. Also, 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 object to be measured into first branched light and second branched light, and the first branched light is While outputting to the spectroscope, the second branched light is output to the imaging unit, the imaging unit that receives the second branched light captures an image of the measurement object, and the image of the measurement object captured by the imaging unit is displayed on the display unit. Display is preferred. It is preferable that the display section displays the spectroscopic measurement range of the spectrometer in the image of the object to be measured. In the non-contact spectroscopic measurement method of the present invention, a beam splitter provided in the middle of the second optical path outputs light from the object to be measured to the spectroscope, and transmits laser light from the laser light source along the second optical path. Output to the object to be measured is preferred. 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 becomes easy to properly evaluate the measurement object.

FIG. 1 is a diagram showing the configuration of a non-contact spectroscopic measurement device 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 spectroscopic measurement device 1A of the first embodiment. FIG. 3 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1B according to the second embodiment. FIG. 4 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1C according to the third embodiment. FIG. 5 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1D according to the fourth embodiment. FIG. 6 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1E according to the fifth embodiment. FIG. 7 is a flow chart 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 this 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 showing the third spectrum Sp3. FIG. 13 is a diagram schematically showing the fourth spectrum Sp4. FIG. 14 is a diagram schematically showing the fifth spectrum Sp5. FIG. 15 is a graph showing the directivity of the spectroscope 20 in the vertical direction. FIG. 16 is a graph showing the horizontal directivity of the spectroscope 20. As shown in FIG. FIG. 17 is a diagram showing the first spectrum Sp1 acquired in the first spectrum acquisition step St11. FIG. 18 is a diagram showing the second spectrum Sp2 acquired in the second spectrum acquisition step St12. FIG. 19 is a diagram showing the third spectrum Sp3 acquired in the third spectrum acquisition step St13. FIG. 20 is a diagram showing the output light spectrum Sp0 and the third spectrum Sp3 of the light source 10. FIG. FIG. 21 is a diagram showing the fourth spectrum Sp4 acquired in the fourth spectrum acquisition step St14. FIG. 22 is a diagram showing the fourth spectrum Sp4 obtained in the fourth spectrum obtaining step St14 using each of the 16 Komatsuna leaves as the measurement object. FIG. 23 is a diagram showing the fifth spectrum Sp5 obtained in the fifth spectrum obtaining 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 measured value by the SPAD meter. FIG. 25 is a diagram showing spectra Sp1 to Sp3 when a fluorescent lamp is used as the ambient light source. FIG. 26 shows spectra Sp1 to Sp3 when a xenon lamp is used as the ambient light source. FIG. 27 is a diagram showing spectra Sp1 to Sp3 when a red light is used as the ambient light source. FIG. 28 is a diagram showing the third spectrum Sp3 when a fluorescent lamp, a xenon lamp, and a red lamp are used as ambient light sources. FIG. 29 shows spectra obtained by standardizing the third spectrum Sp3 by SNV correction when a fluorescent lamp, a xenon lamp, and a red lamp are used as ambient light sources. FIG. 30 is a diagram showing the second spectrum Sp2 when a fluorescent lamp, a xenon lamp, and a red lamp are used as ambient light sources. FIG. 31 shows spectra obtained by standardizing the second spectrum Sp2 by SNV correction when a fluorescent lamp, a xenon lamp, and a red lamp are used as ambient light sources. FIG. 32 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1F according to the sixth embodiment. FIG. 33 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1G according to the seventh embodiment. FIG. 34 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1H according to the eighth embodiment. FIG. 35 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1I according to the ninth embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION 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 overlapping descriptions are omitted. The present invention is not limited to these exemplifications, but is indicated by the scope of the claims, and is intended to include all modifications within the meaning and scope of equivalents of the scope of the claims.

First, the non-contact spectroscopic measurement device 1A of the first embodiment will be described. FIG. 1 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1A according to the first embodiment. A non-contact spectroscopic measurement device 1A includes a measurement head 2A and a control device 3. FIG. The measurement head 2A includes a light source 10, a spectroscope 20, an imaging section 30, a first polarizer 41, a second polarizer 42, a shutter 51, a beam splitter 52, a lens 54 and an aperture 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 spectroscopic measurement device 1A of the first embodiment. 2, illustration of the shutter 51 and the beam splitter 52 is omitted.

The light source 10 outputs broadband light. As the light source 10, one that outputs light in a wavelength band corresponding to the measurement target Sa, which is the object of spectroscopic measurement, evaluation items by spectroscopic measurement, etc., is used. The output wavelength band of light source 10 may include the infrared region or the visible region, and may also include the 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. Further, the light source 10 may be, for example, one that can be repeatedly turned on and off in units of seconds, or one that can operate as a strobe to emit high-intensity light in a short period of time (for example, a xenon flash light source, single-lens light source, etc.). flash lamps for reflex cameras, LED flash lamps for compact cameras, etc.).

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 the light output from the light source 10 and outputs specific polarized light (linearly polarized light in a specific direction or circularly polarized light in a specific rotational direction) to the measurement object Sa. The shutter 51 controls irradiation/non-irradiation of the measurement object Sa with the light output from the light source 10 . The shutter 51 may control irradiation/non-irradiation of light to the measurement object Sa by inserting/withdrawing a shielding plate with respect to the first optical path from the light source 10 to the measurement object Sa. Further, the shutter 51 may control irradiation/non-irradiation of light to the measurement object Sa by transmission/blocking of light of a liquid crystal panel arranged on the first optical path. Without providing the shutter 51, irradiation/non-irradiation of light to the measuring object Sa may be controlled by emission/non-emission of light from the light source 10. FIG. In addition, by repeating light irradiation/non-irradiation to the measurement object Sa multiple times in a short period (for example, several tens of ms to several hundreds of ms), it is possible to follow short-term changes in ambient light such as sunshine. In this case, each of the irradiation time and the non-irradiation time may be set to 100 ms, for example.

The second polarizer 42 , lens 54 and diaphragm 55 are provided in the middle of the second optical path from the measurement object Sa to the spectroscope 20 . The second polarizer 42 receives the light generated by the measurement object Sa and outputs the light other than the specific polarized light to the spectroscope 20 . The lens 54 receives the light generated in the light-irradiated area of the measurement object Sa and passes through the second polarizer 42 to form an image of the light-irradiated area on the imaging plane 22 . A light entrance slit 21 of the spectroscope 20 is on the imaging plane 22 . The diaphragm 55 is provided after the lens 54 and limits the direction (directivity) of light incident on the light entrance slit 21 of the spectroscope 20 .

By appropriately selecting the focal length of the lens 54 and the aperture diameter of the diaphragm 55, the measurement object Sb can be imaged on the image plane 22 . As a result, the degree of freedom in setting the distance between the measuring object Sa and the device can be increased. Also, the smaller the size of the light entrance slit 21 of the spectroscope 20, the narrower the range of spectroscopic measurement by the spectroscope 20, and the narrower the measurement angle θ and the higher the directivity can be realized.

The spectroscope 20 acquires the spectrum of the light that has passed through the light entrance slit 21 out of the light that has arrived from the measurement object Sa. Spectroscope 20 has sensitivity in the band of light output from light source 10 . It is preferable that the spectral wavelength band of the spectroscope 20 is included in the wavelength band of the white light output from the light source 10 . The spectroscope 20 acquires the first spectrum while the light output from the light source 10 is applied to the measurement object Sa, and obtains the first spectrum during the period when the measurement object Sa is not irradiated with the light output from the light source 10. Acquire a second spectrum.

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 by MOEMS (Micro Opto Electro Mechanical Systems) technology, and have a size of W20.1 x D12.5 x H10.1 mm. Since it is small in size, it is suitable for constructing the non-contact spectroscopic measurement device 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 splits the light output from the second polarizer 42 into two into first split light and second split light, outputs the first split light to the spectroscope 20, and outputs the second split light to the imaging unit. 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 measuring head 2A. The control device 3 controls the operation of the measurement head 2A (for example, irradiation/non-irradiation of the measurement object Sa, spectrum acquisition by the spectroscope 20, and imaging by the imaging unit 30). The control device 3 includes a display section 3 a that receives image data output from the imaging section 30 and displays an image of the measurement object Sa captured by the imaging section 30 . Also, the control device 3 is used as a computing unit that inputs the first spectrum and the second spectrum acquired by the spectroscope 20 and performs a predetermined computation (described later) based on those spectra. Although a personal computer (PC) is used as the control device 3, it is preferable to use a small and portable notebook PC or tablet PC.

The first polarizer 41 outputs specific polarized light (linearly polarized light in a specific direction or circularly polarized light in a specific rotational direction) of broadband white light (generally unpolarized light) output from the light source 10 . On the other hand, the second polarizer 42 outputs the light excluding the specific polarized light from the light generated by the measurement object Sa. That is, the second polarizer 42 converts the light that is output from the light source 10 into the specific polarized light by the first polarizer 41 and is applied to the measurement object Sa, the specific polarized light that is reflected by the surface of the measurement object Sa. It selectively blocks the light that maintains the specific polarization, and selectively blocks the light that maintains the specific polarization among the diffusely reflected light (generally unpolarized light) that reflects the light absorption inside the measurement object Sa. selectively transmits the light of the polarization component of . The light output from the second polarizer 42 is the diffusely reflected light reflecting the light absorption inside the measurement object Sa, excluding the specific polarized light. Such diffusely reflected light is received by the spectroscope 20 and the imaging section 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 so that the polarization orientations of the linearly polarized light output by each 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 with the same rotational orientation. Such a polarizer generally has a structure in which a linear polarization 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 output linearly polarized light having the same polarization direction. The broadband white light output from the light source 10 passes through the linear polarization filter layer of the first polarizer 41 to be in a specific linear polarization state, and then passes through the quarter-wave plate layer of the first polarizer 41. As a result, it becomes either a left-handed circularly polarized state or a right-handed circularly polarized state. When the measurement object Sa is irradiated with the circularly polarized light output from the first polarizer 41, the light reflected by the surface of the measurement object Sa becomes circularly polarized light with a direction of rotation opposite to that of the irradiation light. Therefore, when the light is linearly polarized by the quarter-wave plate layer of the second polarizer 42 , it is blocked by the linearly polarized light filter layer of the second polarizer 42 . Therefore, the light output from the second polarizer 42 is the light excluding the specific polarized light among the diffusely reflected light that reflects the light absorption inside the measurement object Sa.

The direction in which the light output from the light source 10 is irradiated 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 is transmitted from the measurement object Sa to the spectroscope 20 and the imaging. Let α be the angle formed by the direction of light emitted to the section 30 (the direction of the second optical path in the measurement object Sa). Preferably, this angle α is 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 becomes the same as the light receiving range of the spectroscope 20 and the imaging. It can be set so as to overlap with 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. Moreover, the narrower the irradiation range Ra, the better. Therefore, it is preferable to use a light source 10 whose output light includes visible light and which can be regarded as a point light source as much as possible, and to form an irradiation range Ra with a clear outline by an irradiation optical system. .

In addition to displaying the image of the measurement object Sa captured by the imaging unit 30, the display unit 3a of the control device 3 displays the range in which the spectroscope 20 spectroscopically measures the image of the measurement object Sa. It is preferred to display the range Rb). By doing so, it becomes easy to spectroscopically measure a desired range of the measurement object Sa.

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

In the measurement head 2B of the second embodiment, the first optical path leading from the light source 10 to the measurement object Sa and the second optical path leading from the measurement object Sa to the spectroscope 20 are arranged so that light enters the measurement object Sa. The emitted portion (the portion of the optical path between the measuring object Sa and the beam splitter 52) is a common optical path.

A first polarizer 41 and a shutter 51 are arranged on the optical path between the light source 10 and the beam splitter 52 . A second polarizer 42 is arranged in 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.

Broadband white light output from the light source 10 is converted into specific polarized light 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 transmitted through the beam splitter 52 and applied to the measuring object Sa. At this time, 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 . Also, the light generated by the measurement object Sa is reflected by the beam splitter 52 and output to the spectroscope 20 .

In the non-contact spectroscopic measurement device 1B of the second embodiment, since the portions of the first optical path and the second optical path where light enters and exits the measurement object Sa are common optical paths, Even if the distance is changed, the irradiation range Ra can be formed with spot illumination having a clear contour, and one point or a part of the range can be reliably spectroscopically measured.

Next, the non-contact spectroscopic measurement device 1C of the third embodiment will be described. FIG. 4 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1C according to the third embodiment. A non-contact spectroscopic measurement device 1C includes a measurement head 2C and a control device 3 . A measuring head 2C according to the third embodiment shown in FIG. 4 further includes a beam splitter 53, a beam damper 57 and an imaging section 30 in addition to the configuration of the measuring head 2B according to the second embodiment shown in FIG. In the following, differences from the configuration of the non-contact spectroscopic measurement device 1B of the second embodiment are mainly described.

A beam splitter 53 is also provided in addition to the beam splitter 52 in the measurement head 2C of the third embodiment. The beam splitter 53 is arranged on the optical path between the first polarizer 41 and the shutter 51 and the beam splitter 52 .

A first polarizer 41 and a shutter 51 are arranged on the optical path between the light source 10 and the beam splitter 53 . A second polarizer 42 is arranged in 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.

Broadband white light output from the light source 10 is converted into specific polarized light 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 is transmitted through the beam splitter 53 and 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 to irradiate the measuring object Sa. 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 .

Part of the light generated by the measurement 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 section 30 .

In the non-contact spectroscopic measurement apparatus 1C of the third embodiment as well, the first optical path and the second optical path have a common optical path where light enters and exits the object to be measured Sa. Even if the distance is changed, the irradiation range Ra can be formed with spot illumination having a clear contour, and one point or a part of the range can be reliably spectroscopically measured. Further, the non-contact spectroscopic measurement device 1C of the third embodiment is provided with 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 can be displayed in the image. can be displayed.

Next, a non-contact spectroscopic measurement device 1D according to the fourth embodiment will be described. FIG. 5 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1D according to the fourth embodiment. A non-contact spectroscopic measurement device 1D includes a measurement head 2D and a control device 3. FIG. Compared to the configuration of the measuring head 2B in the second embodiment shown in FIG. 3, the measuring head 2D in the fourth embodiment shown in FIG. The difference is that the child 40 is provided. In the following, differences from the configuration of the non-contact spectroscopic measurement device 1B of the second embodiment are mainly described.

In the measurement head 2D according to the fourth 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 emitted 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 arranged in the common optical path.

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 specific circularly polarized light by the polarizer 40, and irradiated onto the measurement object Sa. At this time, 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 measurement 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, the non-contact spectroscopic measurement device 1E of the fifth embodiment will be described. FIG. 6 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1E according to the fifth embodiment. A non-contact spectroscopic measurement device 1E includes a measurement head 2E and a control device 3. FIG. Compared with the configuration of the measuring head 2C in the third embodiment shown in FIG. 4, the measuring head 2E in the fifth embodiment shown in FIG. The difference is that the child 40 is provided. Differences from the configuration of the non-contact spectroscopic measurement device 1C of the third embodiment will be mainly described below.

In the measurement head 2E according to 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 emitted 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 arranged in the common optical path.

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 is transmitted through the beam splitter 53 and 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 to specific circularly polarized light by the polarizer 40, and irradiated to the measurement object Sa. 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, part of the light generated by the measurement 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 section 30 .

Next, the non-contact spectroscopic measurement device 1F of the sixth embodiment will be described. FIG. 32 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1F according to the sixth embodiment. The non-contact spectroscopic measurement device 1F includes a measurement head 2F and a control device 3. The measuring head 2F according to the sixth embodiment shown in FIG. 32 has an optically superior position between the light source 10, the spectroscope 20, and the imaging unit 30 when compared with the configuration of the measuring head 2C according to the third embodiment shown in FIG. They differ in terms of arrangement. Differences from the configuration of the non-contact spectroscopic measurement device 1C of the third embodiment will be mainly described below.

In the measurement head 2F according to the sixth embodiment, beam splitters 52 and 53 are provided in the optical path between the imaging section 30 and the measurement object Sa. Of the beam splitters 52 and 53, the beam splitter 52 provided at a position closer to the measurement object Sa reflects the light output from the light source 10 and transmitted through the first polarizer 41 toward the measurement object Sa, Also, the light arriving from the measurement object Sa is transmitted toward the second polarizer 42 . Of the beam splitters 52 and 53, the beam splitter 53, which is provided at a position closer to the imaging unit 30, splits the light arriving from the beam splitter 52 through the second polarizer 42 into two, and one of the split lights is sent to the spectroscope. 20 and the other branched light is output to the imaging unit 30 .

Broadband white light output from the light source 10 is converted into specific polarized light 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 to irradiate the measuring 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 .

The 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 portion 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 spectroscope 20 , and the remaining portion is transmitted through the beam splitter 53 and output to the imaging section 30 .

In the sixth embodiment, there is only one beam splitter through which the light output from the light source 10 passes until the measurement object Sa is irradiated. can be made smaller. Therefore, it is possible to use the light source 10 with a low amount of light, and it is possible to reduce the power consumption of the device, downsize it, and improve its portability.

Next, the non-contact spectroscopic measurement device 1G of the seventh embodiment will be described. FIG. 33 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1G according to the seventh embodiment. The non-contact spectroscopic measurement device 1G includes a measurement head 2G and a control device 3. Compared with the configuration of the measuring head 2F according to the sixth embodiment shown in FIG. 32, the measuring head 2G according to the seventh embodiment shown in FIG. The difference is that the child 40 is provided. Differences from the configuration of the non-contact spectroscopic measurement device 1F of the sixth embodiment will be mainly described below.

In the measurement head 2G of the seventh embodiment, a polarizer 40 is arranged 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 .

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 to specific circularly polarized light by the polarizer 40, and applied to the measurement object Sa. Part of the light input from the light source 10 to the beam splitter 52 passes through the beam splitter 52 , and the transmitted light is absorbed by the beam damper 56 .

The light generated by the measurement object Sa is input to the beam splitter 53 through the beam splitter 52 after the specific circularly polarized light is removed by the polarizer 40 . A portion 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 spectroscope 20 , and the remaining portion is transmitted through the beam splitter 53 and output to the imaging section 30 .

In the seventh embodiment as well, the light output from the light source 10 passes through only one beam splitter until the light emitted to the measurement object Sa is irradiated. can be made smaller. Therefore, it is possible to use the light source 10 with a low amount of light, and it is possible to reduce the power consumption of the device, downsize it, and improve its portability.

Next, the non-contact spectroscopic measurement device 1H of the eighth embodiment will be described. FIG. 34 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1H according to the eighth embodiment. A non-contact spectroscopic measurement device 1H includes a measurement head 2H and a control device 3. FIG. The measuring head 2H according to the eighth embodiment shown in FIG. 34 has a configuration of the measuring head 2F according to the sixth embodiment shown in FIG. differ in Differences from the configuration of the non-contact spectroscopic measurement device 1F of the sixth embodiment will be mainly described below.

In the measurement head 2F according to the sixth embodiment, 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 spectroscope 20, and the rest of the light is transmitted through the beam splitter 53. It is output to the imaging unit 30 . On the other hand, in the measuring head 2H according to the eighth embodiment, 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 imaging unit 30, and the rest is reflected by the beam splitter 53. 53 and output to the spectroscope 20 . Lens 54 and diaphragm 55 are provided between beam splitter 53 and spectroscope 20 .

The non-contact spectroscopic measurement device 1H of the eighth embodiment configured in this way also has the same effects as the non-contact spectroscopic measurement device 1F of the sixth embodiment. In the configurations of the first embodiment (FIG. 1) and the seventh embodiment (FIG. 33) as well, it is possible to change the arrangement of the spectroscope 20 and the imaging unit 30 with respect to the beam splitter.

Next, the non-contact spectroscopic measurement device 1I of the ninth embodiment will be described. FIG. 35 is a diagram showing the configuration of a non-contact spectroscopic measurement device 1I according to the ninth embodiment. A non-contact spectroscopic measurement device 1I includes a measurement head 2I and a control device 3 . A measuring head 2I according to the ninth embodiment shown in FIG. 35 differs from the configuration of the measuring head 2F according to the sixth embodiment shown in FIG. , in that a beam damper 57 is further provided. Differences from the configuration of the non-contact spectroscopic measurement device 1F of the sixth embodiment will be mainly described below.

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

Part of the light that has entered 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 spectroscope 20 . A part of the laser light input from the laser light source 60 to the beam splitter 53 is transmitted through the beam splitter 53 and output to the measurement object Sa along the second optical path, and the remaining part is reflected by the beam splitter 53 to the beam damper 57. absorbed by

The irradiation position of the laser beam on the measurement object Sa indicates the position or range in which spectroscopic measurement is possible. In other words, the laser light source 60 is used as a laser pointer that indicates the spectrometrically measurable position or range. This facilitates confirmation of the irradiation range or spectroscopic range on the measurement object Sa.

Also 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), , a laser light source 60 can be used in place of the imaging unit 30 . Also, it is possible to change the arrangement of the spectroscope 20 and the laser light source 60 with respect to the beam splitter.

Next, the operation of the non-contact spectroscopic measurement device of this embodiment will be described, and the non-contact spectroscopic measurement method of this embodiment will be described with reference to FIGS. 7 to 14. FIG. The following explanation of the operation can be applied to any of the non-contact spectroscopic measurement devices of 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 flow chart of the main routine. FIG. 8 is a flowchart of the 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 showing the third spectrum Sp3. FIG. 13 is a diagram schematically showing 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 formula has not yet been acquired (No in step St3), the evaluation formula is acquired (step St4). The evaluation formula expresses the correlation between the relative reflectance spectrum Sp5 (described later) and the evaluation value, and is used when evaluating the measurement object based on the relative reflectance spectrum Sp5.

When the output light spectrum Sp0 of the light source 10 and the evaluation formula are prepared, the relative reflectance spectrum Sp5 is obtained for each measurement object (step St5), and based on the obtained relative reflectance spectrum Sp5 and the evaluation formula The object to be measured is evaluated (evaluation step St6). Objects to be measured and evaluation items are, for example, the chlorophyll concentration of plants, the sugar content of fruits, the taste of rice, the fat of beef, the fat of fish, the nutritional components of feed, the components contained in building materials, and the like. A detailed procedure for acquiring the relative reflectance 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 light source 60 are both turned off. Both of the light sources 60 are turned on, and the irradiation range or spectroscopic range on the measurement object Sa is confirmed and set to a desired range. After that, the laser light source 60 is turned off, and the processing shown in FIG. 8 is performed.

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

In the first spectrum acquisition step St11, the broadband light output from the light source 10 is converted into specific polarized light by the first polarizer 41 provided in the middle of the first optical path from the light source 10 to the object to be measured. to irradiate. During the irradiation period, the second polarizer 42 provided in the middle of the second optical path leading from the measurement object to the spectroscope 20 causes the light generated in the measurement object, excluding the light of the specific polarized light, to pass through the spectroscope. 20, and the spectroscope 20 obtains the spectrum of the incident light (first spectrum Sp1). This first spectrum Sp1 (FIG. 10) is a spectrum of diffusely reflected light reflecting light absorption inside the measurement object when light from the light source 10 is irradiated onto the measurement object. and the spectrum of the dark signal of the spectroscope 20 . The ambient environment light is, for example, sunlight in the case of outdoors, and is, for example, the light of indoor lighting in the case of indoors.

In the second spectrum acquisition step St12, the spectroscope 20 acquires the spectrum (second spectrum Sp2) of the light incident on the spectroscope 20 while the object to be measured is not irradiated with the light output from the light source 10. The second spectrum Sp2 ( FIG. 11 ) includes the spectrum of the reflected light generated by the object to be measured when the object to be measured is irradiated with the ambient light, and the spectrum of the dark signal from the spectroscope 20 . In addition, in FIG. 11, the dashed line indicates the spectrum of the dark signal of the spectroscope 20. As shown in FIG.

The control device 3 receives the above-described first spectrum Sp1 and second spectrum Sp2 from the spectroscope 20, and performs the subsequent 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 has the influence of the ambient light and the dark signal of the spectroscope 20 removed, and is measured by irradiating the measurement object with the light from the light source 10. It represents the spectrum of diffusely reflected light reflecting the light absorption inside the object. By performing such subtraction to obtain the third spectrum Sp3, it is possible to remove the influence of the ambient light, which varies with each measurement, and also to remove the influence of the dark signal of the spectroscope 20, which generally varies with temperature. be able to.

In the 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 the fourth spectrum Sp4 (=Sp3/Sp0) is obtained as the division result. A fourth spectrum Sp4 (FIG. 13) obtained by this division represents a reflectance spectrum.

Normally, when obtaining the reflectance spectrum of an object to be measured, it is placed at the position of the object to be measured under the same lighting conditions, including the ambient light, before and after obtaining the spectrum of the reflected light from the object. A spectrum of reflected light from a standard white plate or the like is obtained and used as an illumination light spectrum. However, for example, in an outdoor field, the lighting conditions vary greatly depending on the sunlight conditions and the distance from the light source. Therefore, when using the standard white plate, it is necessary to acquire the illumination light spectrum for each measurement. Repeating this work in the field is complicated and becomes a heavy labor burden. Therefore, in the present embodiment, it is convenient to acquire the output light spectrum Sp0 of the light source 10 in advance, and to acquire only the reflected light spectrum and calculate the reflected light spectrum in the field such as a field.

In the evaluation step St6 described above, the object to be measured 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 object to be measured will be different each time the measurement is performed, and it is conceivable that the irradiation intensity on the object to be measured will be different. Therefore, the fourth spectrum Sp4 obtained at each measurement is different, and evaluation of the object to be measured based on the fourth spectrum Sp4 may not lead to proper results. Therefore, in the evaluation step St6, it is preferable to evaluate the object to be measured based on the relative reflection spectrum (fifth spectrum) Sp5 obtained in the fifth spectrum acquisition step St15 described below.

In the fifth spectrum acquisition step (standardization step) St15, the fourth spectrum Sp4 is standardized to obtain a fifth spectrum Sp5 (FIG. 14). There are various methods of standardization processing, and standardization processing by SNV correction (Standard Normal Variate Correction) is as follows. The fourth spectrum Sp4 is represented as I(λ) as a function of wavelength λ, and the average value of I(λ) in a certain wavelength range is I _ave and the standard deviation is I _stddev . When the fifth spectrum Sp5 is expressed as I'(λ) as a function of the wavelength λ, it is represented by the formula I'(λ)={I(λ)−I _ave }/I _stddev . 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 polarized light is provided in the middle of the second optical path from the measurement object to the spectroscope 20. A child 42 is provided. Then, the diffusely reflected light reflecting the light absorption inside the object to be measured is selectively received by the spectroscope 20 by the first polarizer 41 and the second polarizer 42, and the spectrum of this diffusely reflected light is divided into spectroscopies. obtained by device 20 . Therefore, the degree of freedom in setting the optical system between the non-contact spectroscopic measurement device and the object to be measured is high, and it becomes easy to properly evaluate the object to be measured.

Further, in the present embodiment, the irradiation optical system forms an irradiation range Ra with a clear contour on the object to be measured. Alternatively, the spectroscopic range Rb is displayed in the image of the object to be measured by the imaging unit and the display unit. As a result, it is easy to confirm the irradiation range Ra or the spectroscopic range Rb on the object to be measured. It becomes easy to stably acquire the spectrum of the diffusely reflected light.

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

In the examples described below, using the non-contact spectroscopic measurement device 1A of the first embodiment shown in FIG. (SPAD-502 manufactured by Konica Minolta, Inc.). In addition, this SPAD meter can measure the chlorophyll concentration of the measurement object by sandwiching the measurement object between the light source unit and the detection unit and measuring the absorptivity of a plurality of wavelengths. Since this SPAD meter contacts the object to be measured during measurement, there is a risk of contamination of the object to be measured (mediated by pathogens and the like).

An object to be measured (Komatsuna) was placed on a workbench in the laboratory, and a non-contact spectrometer was placed above the workbench. Ambient ambient light was primarily room lighting. The first optical path leading from the light source 10 to the object to be measured was vertically downward from above the object to be measured. The second optical path from the object to be measured to the spectroscope 20 was set at 45° above the horizontal direction. A halogen lamp was used as the light source 10 . Since an irradiation light band of 700 nm or more is necessary to obtain the SPAD value, a halogen lamp without an infrared cut filter was used. A micro-spectroscope C12666MA manufactured by Hamamatsu Photonics K.K. was used as the spectroscope 20 . 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 . Polarizers that output circularly polarized light were used as the first polarizer 41 and the second polarizer 42 .

The white light emitted from the light source 10 was guided by a light guide, passed through the aperture, and irradiated in a spot shape with a clear contour on the object to be measured. Also, the area of the measurement object illuminated in the form of a spot was imaged by the imaging unit 30 and displayed by the display unit 3a. In addition, the display unit 3a displayed a circle around the intersection of the crosshairs in the center of the screen as the spectroscopic measurement range (spectroscopic range Rb) of the spectroscope 20 in the image of the object to be measured. FIG. 15 is a graph showing the directivity of the spectroscope 20 in the vertical direction. FIG. 16 is a graph showing the horizontal directivity of the spectroscope 20. As shown in FIG. In both figures, the horizontal axis is the angle from the optical axis of the spectroscope, 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, an angular range of 2° across the optical axis of the spectroscope is roughly estimated and indicated by a circle as the spectroscopic range Rb.

By using the spectroscopic range Rb on the display unit 3a, spectroscopic measurement can be performed while avoiding foreign matter on the measurement target or non-target parts (leaf veins, etc.), 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 makes a similar contribution. On the other hand, the commercially available SPAD meter, which is used by sandwiching the leaf of the object to be measured, has a problem 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 diaphragm 55, the hyperfocal distance is set to 250 mm, and all objects to be measured located at a distance of 125 mm or more from the lens 54 are focused on the back focal point of the lens 54. I tried to imagine Therefore, in this example, acquisition of the first spectrum Sp1 and the second spectrum Sp2 was possible without focusing as long as the object to be measured was separated from the lens 54 by 125 mm or more.

FIG. 17 is a diagram showing the first spectrum Sp1 acquired in the first spectrum acquisition step St11. FIG. 18 is a diagram showing the second spectrum Sp2 acquired in the second spectrum acquisition step St12. FIG. 19 is a diagram showing 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 the ambient light and the dark signal of the spectroscope 20. It represents the spectrum of diffusely reflected light reflecting the light absorption inside. These spectra Sp1, Sp2, and Sp3 are raw data from the spectrometer 20 and have not undergone wavelength sensitivity correction. There is no problem because it divides .

FIG. 20 is a diagram showing the output light spectrum Sp0 and the third spectrum Sp3 of the light source 10. FIG. FIG. 21 is a diagram showing the fourth spectrum Sp4 acquired in the fourth spectrum acquisition step St14. A fourth spectrum Sp4 (=Sp3/Sp0) represents a reflectance spectrum. In the wavelength band of about 400 nm or less, the intensity of the output light spectrum Sp0 is small, so the noise of the fourth spectrum Sp4 is large. Further, 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, the wavelength band of 500 nm or longer will be treated.

FIG. 22 is a diagram showing the fourth spectrum Sp4 obtained in the fourth spectrum obtaining step St14 using each of the 16 Komatsuna leaves as the measurement object. FIG. 23 is a diagram showing the fifth spectrum Sp5 obtained in the fifth spectrum obtaining step St15 using each of the 16 Komatsuna leaves as the measurement object. Visually, these 16 Komatsuna leaves had varying degrees of green color. Also, the SPAD values of these 16 Komatsuna leaves were measured with a commercially available SPAD meter.

As shown in FIG. 22, the fourth spectrum Sp4 obtained 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 reflectance spectrum (fifth spectrum) Sp5 obtained by subjecting the fourth spectrum Sp4 to the SNV correction process has reduced variations among the 16 Komatsuna leaves. ing.

The correlation between the fifth spectrum Sp5 of each of the 16 Komatsuna leaves and the measurement results by a commercial SPAD meter was evaluated. As a result, it was found that the respective intensities at wavelengths 547 nm and 718 nm in the fifth spectrum Sp5 are highly correlated with the results of measurement by the SPAD meter. Therefore, multiple regression analysis was performed using intensity values near wavelengths of 547 nm and 718 nm in the fifth spectrum Sp5 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 measured value by the SPAD meter. This figure shows locations representing SPAD estimates and SPAD measurements 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, in the relative reflectance spectrum (fifth spectrum) Sp5, if the relative reflectance at a wavelength of 547 nm is R1 and the relative reflectance at a wavelength of 718 nm is R2, the SPAD estimated value in this experimental example The calculation formula for is as follows.
SPAD estimate =6.8139 x R1 + 13.6028 x R2 + 20.8201
If reflectance spectra of individual plant samples are obtained in the field, the corresponding SPAD values can be sequentially obtained 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, results equivalent to those of the conventional SPAD meter can be obtained in a non-contact manner.

Each spectrum was then acquired under various ambient light settings. A fluorescent lamp, a xenon lamp or a red lamp was used as the source of ambient light. In either case, a common light source 10 was used and a common measurement object (Komatsuna) was used. FIG. 25 is a diagram showing spectra Sp1 to Sp3 when a fluorescent lamp is used as the ambient light source. FIG. 26 shows spectra Sp1 to Sp3 when a xenon lamp is used as the ambient light source. FIG. 27 is a diagram showing spectra Sp1 to Sp3 when a red light is used as the ambient light source. The first spectrum Sp1 is the spectrum acquired by the spectroscope 20 when the object to be measured is illuminated by both the light source 10 and the ambient light source. The second spectrum Sp2 is the spectrum acquired by the spectroscope 20 when the object to be measured is illuminated only by the ambient 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 showing the 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 spectra obtained by performing standardization processing by SNV correction on the third spectrum Sp3 when a fluorescent lamp, a xenon lamp, and a red lamp are used as ambient light sources. As shown in FIG. 28, it can be seen that the third spectrum Sp3 before standardization processing differs when the ambient light changes depending on the measurement occasion. On the other hand, as shown in FIG. 29, even if the ambient light is different, the spectra obtained by standardizing the third spectrum Sp3 have substantially the same shape. In other words, it can be seen that the spectra obtained by the standardization process are similar and can be treated as identical when compared in terms of relative intensity.

FIG. 30 is a diagram showing the second spectrum Sp2 when a fluorescent lamp, a xenon lamp, and a red lamp are used as ambient environment light sources. FIG. 31 shows spectra obtained by standardizing the second spectrum Sp2 by SNV correction when a fluorescent lamp, a xenon lamp, and a red lamp are used as ambient light sources. As shown in these figures, when the ambient light varies depending on the occasion of measurement, not only the second spectrum Sp2 before standardization processing differs, but also the spectrum obtained by standardizing the second spectrum Sp2 It turns out different.

Therefore, in order to obtain the spectrum of the reflected light from the object to be measured, it is necessary to spectroscopically measure the reflected light from a white scattering plate or the like placed near the object to be measured to acquire the spectrum of the ambient light. . In addition, acquisition of the ambient light spectrum must be performed for each measurement opportunity. Complicated repetition of this work in the field is a heavy burden of labor. However, in this embodiment, the device has 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 object to be measured can be easily evaluated.

1A to 1I... Non-contact spectroscopic measurement device, 2A to 2I... Measurement head, 3... Control device (calculating unit), 3a... Display unit, 10... Light source, 20... Spectroscope, 30... Imaging unit, 40... Polarizer, 41... First polarizer, 42... Second polarizer, 51... Shutter, 52, 53... Beam splitter, 54... Lens, 55... Diaphragm, 56, 57... Beam damper, 60... Laser light source, Ra... Irradiation range, Rb . . . Spectroscopic range, Sa, Sb .

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, receives light output from the light source, and outputs specific polarized light to the measurement object;
including an imaging plane on which the arriving light is imaged and a light entrance slit provided on the imaging plane, Of the light generated by the measurement objectpasses through the light entrance slit and onto the imaging planea spectroscope for acquiring the spectrum of the light that reaches it;
A second polarized light provided in the middle of a second optical path from the object to be measured to the spectroscope, which receives light generated by the object to be measured and outputs light excluding light of the specific polarized light to the spectroscope. child and
a lens provided in the middle of the second optical path and downstream of the second polarizer for inputting light that has passed through the second polarizer and forming an image on the imaging plane;
a diaphragm provided in the middle of the second optical path and downstream of the lens for limiting the direction of light incidence to the light entrance slit;
From the first spectrum obtained by the spectroscope while the measurement object is irradiated with the light output from the light source, during the period when the measurement object is not irradiated with the light output from the light source, the Subtracting the second spectrum obtained by the spectroscope to obtain a third spectrum as a result of the subtraction, obtaining a fourth spectrum as a result of dividing the third spectrum by the output light spectrum of the light source, obtaining the fourth spectrum or a computing unit that evaluates the measurement object based on a fifth spectrum obtained by processing the fourth spectrum;
A non-contact spectrometry device comprising: 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 device according to claim 1. The first optical path and the second optical path are optical paths in which light enters and exits the measurement object in common.
The non-contact spectroscopic measurement device according to claim 1 or 2. The first polarizer and the second polarizer are polarizers that output linearly polarized light,
The non-contact spectroscopic measurement device 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 spectroscopic measurement device 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 device according to claim 3. a beam splitter that is provided in the middle of the second optical path, splits the light from the object to be measured into first branched light and second branched light, and outputs the first branched light to the spectroscope;
an imaging unit that receives the second branched light output from the beam splitter and images the object to be measured;
a display unit that displays an image of the measurement object captured by the imaging unit;
The non-contact spectroscopic measurement device according to any one of claims 1 to 6, further comprising: The display unit displays a range of spectroscopic measurement by the spectroscope in the image of the object to be measured.
The non-contact spectroscopic measurement device according to claim 7. a laser light source that outputs laser light;
A beam splitter provided in the middle of the second optical path for outputting light from the object to be measured to the spectroscope and for outputting laser light from the laser light source to the object to be measured along the second optical path. When,
The non-contact spectroscopic measurement device according to any one of claims 1 to 8, further comprising: A range in which the measurement object is irradiated with light through the first optical path has a visible spot shape,
The non-contact spectroscopic measurement device according to any one of claims 1 to 9. A first polarizer provided in the middle of a first optical path from a light source to an object to be measured irradiates the object to be measured with broadband light output from the light source as light of specific polarized light, and during the irradiation period, A second polarizer provided in the middle of a second optical path from the object to be measured to the spectroscope, lens and aperturea first spectrum acquisition step of causing light generated in the object to be measured, excluding light of the specific polarization, to enter the spectroscope, and acquiring a first spectrum of the incident light with the spectroscope When,
a second spectrum acquisition step of acquiring, by the spectroscope, a second spectrum of the light incident on the spectroscope during a period in which the object to be measured is not irradiated with the light output from the light source;
a subtraction step of obtaining a third spectrum as a result of subtracting the second spectrum from the first spectrum;
dividing the third spectrum by the output light spectrum of the light source to obtain a fourth spectrum;
an evaluation step of evaluating the measurement object based on the fourth spectrum or a fifth spectrum obtained by processing the fourth spectrum;
equipped with ,
The spectroscope includes an imaging plane on which arriving light is imaged and a light entrance slit provided on the imaging plane, and light generated in the object to be measured passes through the light entrance slit. to acquire the spectrum of the light that has reached the imaging plane,
the lens is provided in the middle of the second optical path and after the second polarizer, and inputs the light that has passed through the second polarizer to form an image on the imaging plane;
The diaphragm is provided in the middle of the second optical path and after the lens, and limits the direction of light incidence to the light entrance slit. ,
Non-contact spectroscopic method. Further comprising a standardization step of standardizing the fourth spectrum to obtain a fifth spectrum,
evaluating the measurement object based on the fifth spectrum in the evaluation step;
The non-contact spectroscopic measurement method according to claim 11. The first optical path and the second optical path are optical paths in which light enters and exits the measurement object in common.
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 spectroscopic measurement 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 spectroscopic measurement 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 first branched light and second branched light, and outputs the first branched light to the spectroscope. , outputting the second branched light to an imaging unit;
imaging the object to be measured by the imaging unit that has received the second branched light;
displaying an image of the measurement object imaged by the imaging unit on a display unit;
The non-contact spectroscopic measurement method according to any one of claims 11 to 16. The display unit displays the spectroscopic measurement range of the spectroscope 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 object to be measured to the spectroscope, and outputs laser light from a laser light source to the object to be measured along the second optical path. do,
The non-contact spectroscopic measurement method according to any one of claims 11 to 18. A range in which the measurement object is irradiated with light through the first optical path has a visible spot shape,
The non-contact spectroscopic measurement method according to any one of claims 11 to 19.

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