JPH09105673A - Spectral apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure the distribution of the colors of an article having a spatial distribution by providing a spectral means disposed so that one axis corresponds to the continuous space coordinates of an object to be measured and the other axis perpendicular thereto corresponds to the wavelength spectrum of the object to be measured, an incident slit, and an image processor. SOLUTION: A spectroscope 10 has a lens 11, an incident slit 12, a diffraction grating 13 and a photoreceiver 14. The lens 11 condenses the light from a sample 2, and focuses the area corresponding to a part from A to B on the sample 2 on the slit 12. The image of the slit 12 is incident on the grating 13, and the light spectrally separated by the grating 13 is incident on the photoreceiver 14. Many photoreceivers are arranged in two-dimensional state in the photoreceiver 14. CCD is normally used as the photoreceiver. With this constitution, the area from A to B on the sample 2 is focused on the slit 12 by the lens 11. The image of the slit 12 is spectrally decomposed into wavelengths from ϕ1 to ψ2 by the grating 13. At this time, the A and B of the space shaft become A", B" of the photoreceiver 14, and decomposed into the wavelengths λ1 to λ2 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectroscopic device capable of measuring the color of an object, and more particularly to a spectroscopic device capable of accurately measuring the color of an object having a spatial distribution in terms of color.

[0002]

2. Description of the Related Art FIG. 8 shows the principle of a conventional spectral colorimetric apparatus of this type. Illumination light from the measurement light source 1 is applied to the surface of the sample 2, and a part of diffused reflection light from the surface of the sample 2 is guided to the light receiver 4 through the monochromator 3 and converted into an electric signal. The portion including the monochromator 3 and the light receiver 4 is a spectrophotometer, and the color of the sample surface can be measured by such a configuration.

[0003]

By the way, since such a color measuring device can measure only one point of information, for a sample having a spatial distribution, an average value of a certain wide area is measured or a spatial value is measured. It was necessary to scan the probe or sample for measurement. However, the former has a drawback that the accuracy is deteriorated, and the latter has a drawback that it takes a long time for measurement and requires a scanning means, which is complicated and expensive. In addition, there is a problem that unevenness in light quantity depending on the location, errors such as vibration, deviation or tilt of the optical axis are likely to occur.

Therefore, in order to measure a sample having a spatial distribution, a color camera 5 may be used as shown in FIG. However, since the color camera uses RGB color filters for measurement, there is a problem that accurate color measurement cannot be performed for the following reasons. (1) True RBG to match the optical characteristics shown in FIG.
The filter also requires a negative characteristic in the standard, but since it cannot be realized in reality, an approximate (approximate curve partially shown by a dotted line) filter is used. (2) Since it is not a spectral measurement, it is not possible to correct the condition color matching (two color stimuli with different spectral distributions appear to be the same color under specific observation conditions). (3) The bright line spectrum of the light source cannot be corrected.

In view of the above points, an object of the present invention is to realize a spectroscopic device capable of accurately measuring the color distribution of an object having a spatial distribution at high speed.

[0006]

In order to achieve such an object, in the first invention of the present application, a spectroscope having a spectroscope including a photodetector in which a large number of photodetectors are two-dimensionally arranged. In addition, one axis corresponds to the continuous spatial coordinates of the measurement target, and the other axis orthogonal to it corresponds to the spectral means installed so as to correspond to the wavelength spectrum of the measurement target, and the continuous measurement target of the measurement target. The axis corresponding to the spatial coordinates is the longitudinal direction and a linear incident slit that allows a part of the light from the measurement object to pass through and enters the spectroscopic means, and receives the output of the spectroscopic means to determine the color distribution of the measurement object. It is characterized in that it is provided with an image processing device for performing processing for obtaining. Further, according to the second invention of the present application, there is provided a spectroscope including a spectroscope including a photodetector in which a large number of photodetectors are arranged in a two-dimensional manner, wherein a wavelength continuous change filter is provided and one axis is measured. Corresponding to the continuous spatial coordinates of the object, the other axis orthogonal thereto corresponds to the wavelength spectrum of the measurement object, and the axis corresponding to the wavelength spectrum is the direction that changes with respect to the wavelength of the wavelength continuous change filter. It is characterized in that it is provided with such a spectroscopic means, and an image processing device for receiving the output of the spectroscopic means and performing processing for obtaining the color distribution of the measurement object.

[0007]

[Operation] The light in the continuous one-dimensional space of the measurement object is dispersed,
Light is received by a light receiver having a two-dimensional light receiving surface. As a result, one axis can be assigned to the spatial distribution, and the wavelength spectrum can be assigned to the other one axis orthogonal to the spatial distribution, and both the spatial distribution and the spectral distribution can be obtained at the same time. In the image processing device, according to the output of the light receiver, JIS Z8722-Z
The color distribution of the measurement object is calculated according to 8729 or the like.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the spectrometer according to the present invention. In the figure, 2 is a sample, 10 is a spectroscopic device, and 20 is an image processing device.

The spectroscopic device 10 comprises a lens 11, an entrance slit 12, a diffraction grating 13, and a light receiver 14. The lens 11 collects the light from the sample 2, and forms an area on the sample 2 on the entrance slit 12 corresponding to A to B. The image of the entrance slit 12 is incident on a diffraction grating 13 as a spectroscopic unit, and the light dispersed by the diffraction grating 13 is incident on a light receiver 14. The diffraction grating 13 has a concave surface, and the light from the entrance slit 12 is focused and enters the light receiver 14. In the figure, the optical path is schematically shown.

The light receiver 14 is formed by arranging a large number of light receiving elements two-dimensionally, and a charge coupled device (CCD: Charge Coupled Device) is usually used as the light receiving element. A metal oxide film (MOS) type camera may be used instead of the CCD. The image processing device 20 uses, for example, the Japanese Industrial Standards JISZ8722 to 872 based on the output of the light receiver 14.
The color of the sample 2 can be calculated according to 9 or the like.

In such a structure, the area corresponding to A to B on the sample 2 is imaged by the lens 11 on the entrance slit 12 of the diffraction grating. Let this be A ', B'. The image of this slit 12 has a wavelength λ due to the diffraction grating 13.
It is spectrally decomposed from ₁ to wavelength λ ₂ . At this time, A and B on the space-time axis become A ″ and B ″ of the photodetector, respectively,
The spectrum is decomposed from ₁ to λ ₂ .

The samples include foods, coatings, moldings, and many one-dimensional objects as shown in FIG. When targeting such a sample, there are cases where it is desired to measure only the vicinity of the center excluding the end because the end includes many errors. At this time, the area AB of the sample 2 is decomposed into wavelengths λ ₁ to λ ₂ in the light receiver 14 as shown in FIG. 2B, and a pattern as shown in FIG. Of these patterns, when a cross section in the AB direction at a specific wavelength λ ₃ is taken, a pattern as shown in FIG. 7D is obtained, and the approximate shape of the sample 2 can be seen.

If only the region C near the center is extracted by image processing or the like in the image processing apparatus 20, the accurate color of the sample can be measured. By measuring the spectrum together with the one-dimensional spatial distribution in this way, the measurement region can be automatically made to correspond to the meandering of the sample 2 and the change of the width. Further, since a true spectrum can be measured instead of the RGB filter, an accurate colorimetric value can be obtained. In addition,
The color is calculated using this spectrum using the Japanese Industrial Standard J
Calculation based on IS Z8722-8729 or the like may be applied.

FIG. 3 shows the case of measuring the color of a wood grain pattern. The area AB of the sample shown in FIG. 3A is spectrally decomposed as shown in FIG.
By taking a cross section in the direction of A-B in ₃ , a pattern as shown in FIG. The part corresponding to the annual ring and the part in between can be measured simultaneously with one measurement. Although not shown, the method of the present invention is also very effective in the case where it is necessary to measure unevenness in the amount of light such as in a liquid crystal panel or a display. However, in this case, the other axis (direction perpendicular to the AB direction) requires mechanical scanning.

The above description merely shows specific preferred embodiments for the purpose of explaining and exemplifying the present invention. It is therefore evident that the present invention is capable of many modifications and variations without departing from its essence. Some other examples will be listed below.

(1) The diffraction grating 13 shown in FIG. 1 may be replaced with a prism. Further, although the entrance slit 12 is arranged on the image forming surface of the lens 11, if fine powder or the like is contained in the sample 2 and causes noise, it is possible to reduce the noise by slightly defocusing the image. It is not necessary to arrange the entrance slit at the position of the surface.

(2) FIG. 4 shows an example in which the continuous wavelength change filter 15 is used instead of the diffraction grating. When the sample 2 is a one-dimensional object in the direction perpendicular to A-B, the wavelength continuous change filter as shown can be used. This filter exhibits characteristics as a bandpass filter in which the central wavelength continuously changes in the λ direction as shown in FIG. 5 by continuously changing the film pressure in the wavelength (λ) direction. If this filter is closely attached to the CCD light receiver 14,
Alternatively, one axis can be used as the wavelength axis and the other axis can be used as the spatial axis by focusing the transmitted light of the filter on the CCD with the relay optical system.

(3) When using a spectroscope such as a diffraction grating,
The entrance slit needs to be linear, but the measurement area on the sample need not be linear either. For example, the optical system 16 between the sample 2 and the entrance slit 12 may be devised so that a fan-shaped measurement region is formed on the sample as shown in FIG.

(4) Furthermore, if a bundle fiber 17 is used as an optical system between the sample 2 and the entrance slit 12,
As shown in FIG. 7, a one-dimensional slit can be associated with a two-dimensional space on the sample (the spatial coordinates of continuous slits correspond to the folded position on the sample). This is particularly effective for measuring the uneven light amount of the display. (5) Further, the image processing device 20 may be included in the spectroscope 10.

[0020]

As described above, according to the present invention, the following effects are exhibited. (1) By using a two-dimensional sensor as a light receiver and assigning one axis to the spatial distribution and the other axis orthogonal to this to the wavelength spectrum, both the spatial distribution and the spectral distribution can be obtained at the same time. This allows the color distribution of an object having a spatial distribution to be measured at high speed. (2) Since the spectrum can be measured directly instead of using the RBG filter, accurate measurement can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a spectroscopic device according to the present invention.

FIG. 2 is an explanatory diagram for measuring a one-dimensional object.

FIG. 3 is an explanatory diagram for measurement of another sample.

FIG. 4 is a configuration diagram showing another embodiment of the present invention.

FIG. 5 is a diagram for explaining the characteristics of a continuous wavelength change filter.

FIG. 6 is a configuration diagram showing still another embodiment of the present invention.

FIG. 7 is a configuration diagram showing still another embodiment of the present invention.

FIG. 8 is a principle diagram of a conventional spectrocolorimeter.

FIG. 9 is a block diagram of an apparatus for measuring spatial distribution with a color camera.

FIG. 10 is a diagram showing optical characteristics.

[Explanation of symbols]

 2 sample 10 spectroscope 11 lens 12 entrance slit 13 diffraction grating 14 light receiver 15 continuous wavelength change filter 16 optical system 17 bundle fiber 20 image processing device

Claims (9)

[Claims] 1. A spectroscopic device having a spectroscope including a photodetector in which a large number of photodetectors are arrayed in a two-dimensional manner, wherein one axis corresponds to continuous spatial coordinates of a measurement target and is orthogonal thereto. The spectroscopic means installed so that the other axis corresponds to the wavelength spectrum of the measurement target, and the axis corresponding to the continuous spatial coordinates of the measurement target becomes the longitudinal direction and passes a part of the light from the measurement target. A spectroscopic device comprising: a linear entrance slit that is incident on the spectroscopic device; and an image processing device that receives an output of the spectroscopic device and performs a process for obtaining a color distribution of the measurement target. 2. The spectroscope has an imaging optical system installed between the measurement object and the spectroscopic means so that a real image of the measurement object is formed on the slit surface of the entrance slit. The spectroscopic device according to claim 1. 3. A charge-coupled device or M as the photodetector.
The spectroscopic apparatus according to claim 1, wherein an OS type camera is used. 4. The spectroscope has an optical element installed between the measuring object and the spectroscopic means and converting so that continuous spatial coordinates of the measuring object correspond to a curved or folded position on the sample. The spectroscopic device according to claim 1, wherein: 5. The spectroscopic apparatus according to claim 1, wherein the spectroscopic means is a diffraction grating or a prism. 6. An optical fiber is used as an optical coupling means between the sample and the spectroscopic means.
Alternatively, the spectroscopic device according to claim 2, claim 3, claim 4, or claim 5. 7. A spectroscope having a spectroscope including a photodetector in which a large number of photodetectors are arranged in a two-dimensional manner, wherein a continuous wavelength change filter is provided and one axis has a continuous space to be measured. Spectral means corresponding to the coordinates, and another axis orthogonal to the coordinates corresponds to the wavelength spectrum of the measurement target, and the axis corresponding to the wavelength spectrum is in the direction of changing with respect to the wavelength of the wavelength continuous change filter. And a spectroscopic device including an image processing device that receives the output of the spectroscopic device and performs a process for obtaining the color distribution of the measurement target. 8. The spectrometer is installed between the measurement target and the continuous wavelength change filter, and forms a real image of the measurement target on the surface of the continuous wavelength change filter or the light receiving surface of the light receiver. The spectroscopic apparatus according to claim 7, further comprising an image optical system. 9. An optical fiber is used as an optical coupling means between the sample and the spectroscopic means.
Alternatively, the spectroscopic device according to claim 8.