JP3493168B2 - Object color measuring method and object color measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to accurately measure the object color of a subject illuminated by any external light, without being affected by the external light and even when the subject moves. The present invention relates to an object color measuring method and an object color measuring device.

[0002]

2. Description of the Related Art In order to measure the spectral reflectance of an object under arbitrary external light, the spectral distribution in the state where known illumination is added to the external light and the spectral distribution in the case of only the external light are respectively measured. , It suffices to compare the spectral intensities at the same position of the subject.

Various measuring methods based on this principle have been proposed so far, but all of them measure two or more times different in time. For this reason, when a moving object is set as a measurement target, it may be difficult to associate the measurement points with each other and the measurement may not be performed correctly.

Among the conventional methods, the method disclosed in Japanese Patent Application Laid-Open No. 8-320382 “Object detecting device and object detecting method” (however, it is not the method of measuring the spectral reflectance of an object)
By modulating the illumination light to the subject and capturing both the image with strong illumination and the image with weak illumination in synchronization with the intensity of the modulation, the image signal of the modulation component is obtained, and it is not affected by external light. It realizes to detect an object.

According to this method, the difference in the photographing time between the image with strong illumination and the image with weak illumination is small, but when the moving speed of the subject is high, it becomes difficult to associate the measurement points.

[0006]

As described above, according to the conventional method, it is difficult to measure a correct object color when an object moving at a high speed is to be measured. .

The present invention has been made in view of the above circumstances, and is provided when the object color of an object illuminated by arbitrary external light is not affected by the external light and the object moves. The object of the present invention is to provide a new object color measurement technology that enables accurate measurement.

[0008]

In order to achieve this object, in the object color measuring method of the present invention, an illumination light generation process,
Illumination spectral distribution acquisition process, subject spectral luminous intensity distribution measurement process, illumination light interpolation spectral distribution calculation process, subject interpolation spectral distribution calculation process, spectral reflectance calculation process, proportional coefficient calculation process, spectral reflectance absolute value A calculation process and an external light spectral distribution calculation process are provided.

In the illumination light generation process, for example, the light source light is filtered by using a filter having a spectral transmission characteristic such that a wavelength region having high light transmittance and a wavelength region having low light transmittance appear repeatedly. Illumination light having a spectral characteristic that a wavelength region having high intensity and a wavelength region having weak intensity appear repeatedly in the wavelength direction is generated.

In the illumination spectral distribution acquisition process, the illumination spectral distribution is acquired by calculating or measuring the spectral distribution e (λ).

In the subject spectrophotometric distribution measurement process, the spectrophotometric distribution F (λ) of the subject illuminated by both external light and illumination light is measured. Here, by taking a spectral image of a subject, the spectral luminous intensity distribution F (λ) at each point of the subject that is a measurement point of the object color may be measured.

In the illumination light interpolation spectral distribution calculation process, only the wavelength region where the light intensity is strong is extracted from the illumination light spectral distribution e (λ), and the spectral distribution e is interpolated in the wavelength direction.
₁ (λ) is calculated and the spectral distribution of illumination light e (λ)
Then, only the wavelength region where the light intensity is weak is taken out, and the spectral distribution e ₀ (λ) is calculated by interpolating it in the wavelength direction.

In the subject interpolation spectral distribution calculation process, the subject
Of the spectral intensity distribution F (λ) of
For the spectrophotometric value by extracting the
Cloth F ₁(λ) is calculated and the spectral distribution of the subject is calculated.
Extract only the wavelength range where the light intensity is weak from F (λ)
Then, it is interpolated in the wavelength direction₀(λ)
calculate.

In the process of calculating the spectral reflectance, e₀(λ), e
₁(λ), F₀(λ), F₁using (λ)hand, r (λ) = [F ₁ ( λ ) -F ₀ ( λ ) ] / [E ₁ ( λ ) -E
₀ ( λ ) ] Based on the calculation formula Relative value of spectral reflectance of image
Calculate r (λ).

In the proportional coefficient calculation process, a reference object whose absolute value Rs (λ) of the spectral reflectance is known is placed at the observation position of the subject, and a relative value r (λ) of the spectral reflectance of the subject is calculated. Using the same procedure, the relative value rs (λ) of the spectral reflectance of the reference object is obtained, and Rs (λ) and rs (λ) and the proportional coefficient α are calculated.

In the process of calculating the spectral reflectance absolute value, the relative value r (λ) of the spectral reflectance of the subject is converted using the proportional coefficient α to calculate the absolute value R (λ) of the spectral reflectance of the subject. To do.

In the process of calculating the external light spectral distribution, a relational expression E (λ) = [F ₀ ( λ ) is established between F ₀ (λ), e ₀ (λ), α, R (λ), and external light. ) / R (λ)] − αe ₀ ( λ ) or F ₁ (λ) and e ₁ (λ), α, R (λ) and the external light E (λ) = [ The spectral distribution E (λ) of external light is calculated from F ₁ ( λ ) / R (λ)] − αe ₁ ( λ ) .

In the object color measuring method of the present invention configured as described above, in the illumination light generation process, an illumination having a spectral characteristic such that a wavelength region where the light intensity is strong and a wavelength region where the light intensity is weak repeatedly appear in the wavelength direction. Produces light.

Since the subject is illuminated by both the illumination light and the external light generated in this way, in the process of measuring the subject spectrophotometric distribution, the spectrophotometric distribution F of the subject at this time is measured.
Measure (λ). On the other hand, in the process of obtaining the illumination spectral distribution, the spectral distribution e (λ) of the illumination light is measured.

In response to this measurement result, in the illumination light interpolation spectral distribution calculation process, only the wavelength region where the light intensity is strong is extracted from the illumination light spectral distribution e (λ) and the spectral distribution is interpolated in the wavelength direction. e ₁ (λ) is calculated, and only the wavelength region where the light intensity is weak is extracted from the spectral distribution e (λ) of the illumination light, and the spectral distribution e ₀ (λ) is interpolated in the wavelength direction.
To calculate.

On the other hand, in the subject interpolation spectral distribution calculation process, only the wavelength region where the light intensity is strong is taken out from the spectral luminous intensity distribution F (λ) of the subject, and the spectral luminous intensity distribution F ₁ (λ) is interpolated in the wavelength direction. Is calculated, and only the wavelength region in which the light intensity is weak is extracted from the spectral light intensity distribution F (λ) of the subject, and is interpolated in the wavelength direction to obtain the spectral light intensity distribution F ₀ (λ).
To calculate.

E ₀ (λ), e calculated in this way
₁ (λ), F ₀ (λ), F ₁ (λ), the absolute value R (λ) of the spectral reflectance of the subject, and the spectral distribution E (λ) of external light are F ₀ ( λ) = [E (λ) + αe ₀ (λ)] R (λ) F ₁ (λ) = [E (λ) + αe ₁ (λ)] R (λ) holds. Here, α is a proportional coefficient determined by the spatial positional relationship between the illumination light and the subject.

From now on, in the process of calculating the spectral reflectance, e
_{Using 0} (λ), e ₁ (λ), F ₀ (λ), F ₁ (λ), αR (λ) = [F ₁ (λ) −F ₀ (λ)] / [e ₁ (λ ) -E
₀ (λ)] is calculated to obtain the relative value r of the spectral reflectance of the subject.
(Λ) (= αR (λ)) is calculated.

Then, in the proportional coefficient calculating process, when the proportional coefficient α is calculated using a reference object whose absolute value Rs (λ) of the spectral reflectance is known, it is calculated in the spectral reflectance absolute value calculating process. The absolute value R (λ) of the spectral reflectance of the subject is calculated by converting the relative value r (λ) of the spectral reflectance of the subject using the proportional coefficient α.

Then, in the process of calculating the external light spectral distribution, the calculated proportional coefficient α and the calculated absolute value R (λ) of the spectral reflectance of the subject are substituted into the above-mentioned relational expression to obtain the spectral distribution of the external light. The distribution E (λ) is calculated.

As described above, according to the present invention, it is possible to measure the spectral reflectance of an object without being affected by external light, by measuring or photographing the object only once. Therefore, it is possible to measure the spectral reflectance and the object color of a fast-moving subject, which has been difficult with the conventional technology.
Then, it becomes possible to measure the spectral reflectance and the object color of the subject from the high-speed moving body.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail according to embodiments.

Before describing specific example embodiments, the definitions of terms and the premise of the present invention will be clarified.

The term “spectral distribution” means a relative distribution of values of some value for each wavelength, and the term “spectral luminous intensity distribution” means that the luminous intensity (absolute value of luminance value) is given for each wavelength. And

When simply referred to as a color, it includes both the spectral distribution of light or the spectral distribution of light, which is a physical expression of color, and the colorimetric value (XYZ value, xy value, etc.), which is a psychophysical expression of color. It represents a broad color. Since there is an integral conversion relationship from the spectral (luminous) distribution to the colorimetric value, spectral (luminous)
If the distribution is obtained, the colorimetric value will be determined, but the opposite cannot be obtained.

In the following, the measurement of the spectral distribution is mainly focused, but it is easy to convert it into a colorimetric value if necessary.

Regarding the measurement of the spectrophotometric distribution, a spectrocolorimeter for measuring the spectrophotometric distribution at one point has been existing and is widely used. Recently, a spectroscopic image measuring device has been developed in which a spectrophotometric distribution is given to each pixel for a plurality of one-dimensional or two-dimensional pixels. In addition, a pseudo spectral image measuring device has been developed which captures images for a plurality of wavelength bands using a large number of bandpass filters.

The present invention can be realized by utilizing these devices, or can be realized by preparing a dedicated device.

FIG. 1 illustrates an example of arrangement of main constituent elements of the present invention. In the figure, 1 is a subject, 2 is a light source, 3 is a filter, 4 is a spectral distribution measuring device, and 5 is a control / arithmetic device.

As shown in this figure, the subject 1 whose spectral distribution is to be measured is illuminated by arbitrary external light (such as the sun), and the spectral distribution E at the subject position of this external light is measured.
Consider the situation where (λ) is unknown.

If the spectral reflectance of the subject 1 is measured only by outside light without using additional illumination, and the spectral reflectance of the subject 1 is R (λ), the observed spectral reflectance f (Λ) is expressed by the following formula: f (λ) = E (λ) R (λ) ....

Here, what we want to measure is the spectral reflectance R (λ), which is a physical expression of the color peculiar to the object, but since the spectral distribution E (λ) of external light is unknown, the observed value f (λ ) Can't ask for this.

First, the basic principle for measuring the spectral reflectance R (λ) of the subject 1 will be described. In addition,
This basic principle is already widely known.

The observation value when illuminating light whose spectral distribution e (λ) is known is added to this state is f ′ (λ) = [E (λ) + αe (λ)] R (λ) ... becomes equation (2). Here, α is a proportional coefficient determined by the spatial positional relationship between the illumination light and the subject.

By subtracting both sides of the equation (1) from the equation (2), f '(λ) -f (λ) = αe (λ) R (λ) (3) , A relational expression that is not affected by the external light E (λ) is obtained.

As the subject 1, a standard reference object (standard white plate or the like) whose spectral reflectance is known is placed at the subject position, and the above-mentioned measurement is performed to determine the value of the proportional coefficient α. Therefore, it is possible to obtain the spectral reflectance R (λ) of the arbitrary subject 1 by using this value.

Various methods of measuring the spectral distribution of the object according to this principle have been proposed so far, but as is clear from this basic principle, it is necessary to perform a plurality of measurements with and without illumination. . For this reason, when the measuring device and the subject 1 move relatively, especially when moving at high speed, it becomes difficult to associate the measurement points with each other, and there is a problem that correct measurement may not be possible.

The present invention utilizes this basic principle, but the spectral distribution of the subject 1 can be measured by performing only one measurement without performing a plurality of measurements, which is a problem of the conventional method. It will be realized.

FIG. 2 shows an embodiment of a processing flow for realizing the object color measuring method of the present invention. Next, the object color measuring method of the present invention will be described in detail according to this processing flow.

In the object color measuring method of the present invention, as shown in the processing flow of FIG. 2, first, in step 1, the light source 2 for illuminating the subject 1 is turned on. It is desirable that the light source 2 has a wide and continuous wavelength distribution in the visible light wavelength region.

Then, in step 2, the light from the light source 2 is made to have characteristics such that a wavelength region having a large light transmittance and a wavelength region having a small light transmittance appear repeatedly in the wavelength direction as shown in FIG. By filtering with the filter 3 which it has, the illumination light with which the to-be-photographed object 1 is irradiated is produced | generated.

In this way, the illumination light having the spectral characteristic such that the wavelength region in which the light intensity is strong and the wavelength region in which the light intensity is weak in the wavelength direction are repeatedly generated is generated.

The filter 3 having the spectral transmittance characteristic as shown in FIG. 3 can be realized by a polarization interference filter.

That is, the polarization interference filter is constructed by placing a birefringent crystal plate having a thickness d in a diagonal position between parallel Nicols, and according to this configuration, transmitted light is transmitted in the wavelength direction as shown in FIG. On the other hand, it is known that it shows periodic light and dark (reference: edited by The Japan Color Society, published by The University of Tokyo Press, new edition "Handbook of Color Science", 2nd edition, pp.869-87.
0).

In addition, light from a light source whose intensity is widely distributed in the wavelength direction such as an incandescent lamp is dispersed by an optical instrument such as a prism or an interference plate having a spectral function, and the dispersed light is spatially filtered. Then, a method of collecting the light again may be used. Further, when a light source generation device having spectral characteristics such that a wavelength region in which light intensity is strong and a wavelength region in which light intensity is weak appear repeatedly in the wavelength direction can be prepared, it may be used.

Then, in step 3, the spectral characteristics of the generated illumination light are obtained by calculating or measuring. The spectral characteristic of the illumination light may be obtained by calculating from the spectral distribution of the light source 2 and the spectral characteristic of the filter 3, or may be obtained by measuring with a spectral luminance meter or the like.

The spectral distribution of this illumination light will be referred to as e (λ). FIG. 4 shows the spectrum of this e (λ).

Then, in step 4, the spectral luminous intensity distribution of the subject 1 illuminated by both the illumination light and the external light is measured.

The spectral luminous intensity distribution of the subject 1 is expressed as F (λ). FIG. 5 shows the F (λ) spectrum. Since the spectral distribution e (λ) of the illumination light shows unevenness as shown in FIG. 4, the spectral luminous intensity distribution F (λ) of the subject 1 measured at this time is also in the wavelength direction as shown in FIG. To show unevenness.

Then, in step 5, considering that the wavelength region in which the light intensity is strong and the wavelength region in which the light intensity is weak are values in different illumination states, the light intensity is strong from the spectral distribution e (λ) of the illumination light. Only the wavelength region is taken out and the spectral distribution e ₁ (λ) is calculated by interpolating it in the wavelength direction, and only the wavelength region where the light intensity is weak is taken out from the illumination light spectral distribution e (λ) Spectral distribution e ₀ (λ) interpolated in the wavelength direction
To calculate.

That is, as shown in FIG.
Spectral distribution e obtained by interpolating a strong wavelength region in the wavelength direction₁(λ)
And a spectrum obtained by interpolating the wavelength range where the light intensity is weak in the wavelength direction.
Distribution e ₀(λ) and are calculated.

Then, in step 6, a wave having a high light intensity is generated.
The long region and the weak wavelength region are values under different illumination conditions.
Considering that there is a light from the spectral intensity distribution F (λ) of the subject 1,
The wavelength range where the intensity of
Spectral intensity distribution F interpolated in the direction ₁When calculating (λ)
In addition, the intensity of light is weak from the spectral luminous intensity distribution F (λ) of the subject 1.
Take out only the wavelength region that is not present and interpolate it in the wavelength direction.
Spectral distribution F₀Calculate (λ).

That is, as shown in FIG.
Spectral distribution F obtained by interpolating the strong wavelength region in the wavelength direction₁(λ)
And a spectrum obtained by interpolating the wavelength range where the light intensity is weak in the wavelength direction.
Distribution F ₀(λ) and are calculated.

FIG. 6 shows an example of the interpolation processing performed in steps 5 and 6.

In the interpolation process shown in this figure, first of all,
The spectral distribution e (λ) or F (λ) is divided into a wavelength region where the light intensity is strong and a wavelength region where the light intensity is weak. That is, the width w _{i of the} wavelength region in which the light intensity is strong is sufficiently narrower than the fluctuation of the spectrum and is divided so as to include the maximum value of the filter intensity, and the width w _{i of the} wavelength region in which the light intensity is weak is set. It is divided so that it is sufficiently narrower than the fluctuation of the spectrum and includes the minimum value of the filter strength.

Then, the intensity y _i for the representative wavelength λ _i (center wavelength of the wavelength region i) in each wavelength region i divided in this way is defined as the integral value S _i of the intensity in the wavelength region i. By dividing it by the width w _i of each of them and interpolating the representative values thereof, e ₁ (λ), e ₀ (λ),
Processing is performed so as to obtain F ₁ (λ) and F ₀ (λ).

E calculated in step 5₁(λ), e₀(λ)
And F calculated in step 6₁(λ), F ₀(λ) and the subject
Absolute value R (λ) of the spectral reflectance and the spectral distribution E of external light
Between (λ), F₀(λ) = [E (λ) + αe₀(λ)] R (λ) F₁(λ) = [E (λ) + αe₁(λ)] R (λ) Is established. Where α is the illumination light and the spatial
It is a proportional coefficient determined by the positional relationship.

Subsequently, in step 7, the 2
ΑR (λ) = [F ₁ (λ) −F ₀ (λ)] / [e ₁ (λ) −e derived from two equations
₀ (λ)], the relative value r (λ) (= α of the spectral reflectance of the subject 1)
R (λ)) is calculated, and the process ends.

As described above, according to the object color measuring method of the present invention in accordance with the processing flow of FIG. 2, the spectral reflectance of the subject 1 is measured only once, without being affected by the external light. It becomes possible to measure the relative value r (λ) of

From this, it becomes possible to measure the spectral reflectance and the object color of an object moving at high speed, which is difficult with the conventional technique, and it is also possible to measure the spectral reflectance and the object color of the object from a high-speed moving object. Become.

FIG. 7 shows another embodiment of the processing flow for realizing the object color measuring method of the present invention.

In accordance with the procedure of the processing flow of FIG. 2, the relative value rs (λ) (= αR) of the spectral reflectance with respect to a reference object such as a standard white plate whose absolute value Rs (λ) of the spectral reflectance is known in advance.
If s (λ)) is calculated, the proportional coefficient α can be obtained by comparing this with the known absolute value Rs (λ) of the spectral reflectance.

By using the value of the proportional coefficient α obtained in this way, the relative value of the spectral reflectance of an arbitrary subject 1 including the uncertainty of the proportional coefficient α obtained by the procedure of the processing flow of FIG. The absolute value R (λ) of the spectral reflectance of the arbitrary subject 1 can be obtained from r (λ).

The processing flow of FIG. 7 is for processing so as to obtain the absolute value R (λ) of the spectral reflectance of the subject 1 by this method.

That is, in the object color measuring method of the present invention according to the processing flow of FIG. 7, steps 1 to 7 are steps 1 to 7 of the processing flow of FIG.
When the relative value r (λ) of the spectral reflectance of the subject 1 is calculated by executing the processing of (1), subsequently, in step 8, the proportional coefficient α is determined.

That is, a reference object whose absolute value Rs (λ) of the spectral reflectance is known is placed at the observation position of the subject 1,
Performing the same processing as Step 4 / Step 6 / Step 7 of the processing flow of FIG. 2 By performing the processing of Step 4 / Step 6 / Step 7, the relative value rs (λ) of the spectral reflectance of the reference object is executed. (= ΑRs (λ)) is measured. Then, the proportional coefficient α is determined by dividing the relative value rs (λ) by the known Rs (λ).

Then, in step 9, the relative value r (λ) (= αR) of the spectral reflectance of the arbitrary subject 1 obtained in step 7 is obtained.
By dividing (λ)) by the proportional coefficient α determined in step 8, the absolute value R (λ) of the spectral reflectance of the subject 1 is calculated, and the process ends.

As described above, according to the object color measuring method of the present invention according to the processing flow of FIG. 7, the absolute value R (λ) of the spectral reflectance of the subject 1 can be obtained.

FIG. 8 shows another embodiment of the processing flow for realizing the object color measuring method of the present invention.

According to the processing flow of FIG. 7, the proportional coefficient α and the absolute value R (λ) of the spectral reflectance of the subject 1 can be calculated.

On the other hand, as described above, F ₀ (λ) = [E (λ) + αe ₀ (λ)] R (λ) F ₁ (λ) = [E (λ) + αe ₁ (λ)] R ( Since the relational expression λ) holds, the spectral distribution E (λ) of external light
Is the expression E (λ) = [F ₀ (λ) / R (λ)] − αe ₀ (λ) E (λ) = [F ₁ (λ) / R (λ)] − αe ₁ (λ) Can be calculated with.

The processing flow of FIG. 8 is for processing to obtain the spectral distribution E (λ) of external light by this method.

That is, in the object color measuring method of the present invention according to the processing flow of FIG. 8, steps 1 to 9 are steps 1 to 9 of the processing flow of FIG.
When the proportional coefficient α and the absolute value R (λ) of the spectral reflectance of the subject 1 are calculated by performing the processing of step S1, the external light spectral distribution E is calculated using the above relational expression in step 10.
Calculate (λ).

[0079] That is, E (lambda) = _{[F 0 (λ) / R (} λ) ] - αe ₀ (λ) of the equation, the calculated _{e 0 (λ), F 0} (λ), α, R
The spectral distribution E (λ) of outside light can be calculated by substituting (λ), or can be calculated by the following equation: E (λ) = [F ₁ (λ) / R (λ)] − αe ₁ (λ) E ₁ (λ), F ₁ (λ), α, R
The spectral distribution E (λ) of external light is calculated by substituting (λ).

In this way, according to the object color measuring method of the present invention in accordance with the processing flow of FIG.
It becomes possible to obtain (λ).

In the embodiment described above, the subject 1
Spectral distribution measuring device 4 for measuring the spectral luminous intensity distribution F (λ) of
(Shown in FIG. 1) was not described.

The spectral distribution measuring device 4 may be any device as long as it has a function of measuring the spectral luminous intensity distribution F (λ) of the subject 1 by one photographing.

For example, the image data of one line of the subject 1 is read through the slit, and the data of each pixel constituting the image data is spectrally divided by using a prism or a grating, which is then used as a two-dimensional image sensor. It is possible to use a device capable of measuring the spectrophotometric distribution F (λ) of each point of the subject 1 located on the line at one time by reading the.

Further, in front of the two-dimensional image sensor, a plurality of optical filters having different spectral transmittances are rotatably arranged at high speed, or an optical filter capable of electronically changing the spectral transmittances is arranged. Then, a device that can instantaneously measure the spectral luminous intensity distribution F (λ) at each point of the subject 1 may be used.

When the spectral distribution measuring device 4 having the function of simultaneously or instantaneously measuring the spectral luminous intensity distributions F (λ) at a plurality of points on the subject 1 is used, the subject is processed according to the processing flow of FIG. Relative value r (λ) of the spectral reflectance of 1
Will be processed to measure.

That is, first, in step 1, the light source 2 for illuminating the subject 1 is turned on. Subsequently, in step 2, the filter 3 having the characteristic that the light from the light source 2 has a wavelength region in which the light transmittance is high and a wavelength region in which the light transmittance is small appears repeatedly in the wavelength direction as shown in FIG. Illumination light that illuminates the subject 1 is generated by filtering with. Subsequently, in step 3, the spectral characteristics of the generated illumination light are obtained by calculating or measuring.

Then, in a step, only the wavelength region having a high light intensity is extracted from the spectral distribution e (λ) of the illumination light, and the spectral distribution e ₁ (λ) is interpolated in the wavelength direction, and at the same time, From the spectral distribution e (λ) of the illumination light, only the wavelength region where the light intensity is weak is extracted, and the spectral distribution e ₀ (λ) is calculated by interpolating it in the wavelength direction.

Then, in step, the spectral distribution measuring device 4 having the function of simultaneously or instantaneously measuring the spectral luminous intensity distributions F (λ) of a plurality of points on the physical object 1 is used.
The spectrophotometric distributions F (λ) at the upper points are measured.

Subsequently, in step, it is determined whether or not the unprocessed pixels (points) measured in the step are left, and it is judged that the unprocessed pixels are not left. At times, when it is determined that the processing is terminated and there is an unprocessed pixel left, the process proceeds to step and one pixel to be processed is selected.

Then, in a step, only the wavelength region where the light intensity is strong is taken out from the spectral luminous intensity distribution F (λ) of the selected pixel and the spectral luminous intensity distribution F is obtained by interpolating it in the wavelength direction.
₁ (λ) is calculated, and only the wavelength region where the light intensity is weak is taken out from the spectrophotometric distribution F (λ) of the selected pixel, and the spectrophotometric distribution F ₀ (λ) is calculated by interpolating it in the wavelength direction. To do.

Then, in a step, αR (λ) = [F ₁ (λ) -F ₀ (λ)] / [e ₁ (λ) -e
₀ (λ)], the relative value r (λ) of the spectral reflectance of the selected pixel
(= ΑR (λ)) is calculated, and the process returns to the step.

As described above, according to the object color measuring method of the present invention in accordance with the processing flow of FIG. 9, the object 1 is photographed only once, and each point of the object 1 is not affected by the external light. It becomes possible to measure the relative value r (λ) of the spectral reflectance.

FIG. 10 shows an embodiment of the object color measuring apparatus of the present invention which realizes the object color measuring method of the present invention according to the processing flow of FIG.

The object color measuring device of the present invention according to this embodiment is a light source light generating device 10 and an illumination light generating device 11.
An illumination spectral distribution measuring device 12 and a measurement control unit A13
A subject spectrophotometric distribution measuring device 14 and a measurement control unit B
15 and a control / arithmetic unit 5.

The light source light generator 10 emits light source light by turning on the light source 2. The illumination light generation device 11 is
Illumination for irradiating the subject 1 by filtering the light source light with a filter 3 having characteristics such that a wavelength region having a large light transmittance and a wavelength region having a small light transmittance appear repeatedly in the wavelength direction as shown in FIG. Produces light.

The illumination spectral distribution measuring device 12 measures the spectral characteristic e (λ) of the illumination light. The measurement control unit A13 controls the measurement process of the illumination spectral distribution measuring device 12. The subject spectrophotometric distribution measuring device 14 measures the spectrophotometric distribution F (λ) of the subject 1 illuminated by both the illumination light and the external light. The measurement control unit B15 controls the measurement process of the subject spectrophotometric distribution measurement device 14.

The control / calculation device 5 includes a calculation control section 50 for controlling the entire control process and an illumination light interpolation spectral distribution calculation section 51.
And a subject interpolation spectral distribution calculation unit 52 and a spectral reflectance calculation unit 53.

The illumination light interpolation spectral distribution calculation unit 51 takes out only the wavelength region where the light intensity is strong from the illumination light spectral distribution e (λ) and interpolates it in the wavelength direction to obtain a spectral distribution e.
₁ (λ) is calculated and the spectral distribution of illumination light e (λ)
Then, only the wavelength region where the light intensity is weak is taken out, and the spectral distribution e ₀ (λ) is calculated by interpolating it in the wavelength direction.

The subject interpolation spectral distribution calculation unit 52 extracts only the wavelength region in which the light intensity is strong from the spectral luminous intensity distribution F (λ) of the subject 1 and interpolates it in the wavelength direction to obtain a spectral luminous intensity distribution F ₁ (λ). Is calculated, and only the wavelength region where the light intensity is weak is extracted from the spectral luminous intensity distribution F (λ) of the subject 1, and the spectral luminous intensity distribution F ₀ (λ) is interpolated in the wavelength direction.
To calculate.

The spectral reflectance calculator 53 calculates αR (λ) = [F ₁ (λ) −F ₀ (λ)] / [e ₁ (λ) −e
₀ (λ)], the relative value r (λ) (= α of the spectral reflectance of the subject 1)
R (λ)) is calculated.

According to this structure, the object color measuring apparatus of the present invention configured as shown in FIG. 10 realizes the object color measuring method of the present invention according to the processing flow of FIG.

FIG. 11 shows an embodiment of the object color measuring apparatus of the present invention which realizes the object color measuring method of the present invention according to the processing flow of FIG.

In the object color measuring device of the present invention according to this embodiment, in addition to the device shown in FIG. 10, the control / calculation device 5 includes a proportional coefficient calculating section 54 and a spectral reflectance absolute value calculating section 5.
5 is adopted.

According to this embodiment, the reference object whose absolute value Rs (λ) of the spectral reflectance is known is the subject 1.
By arranging at the observation position of
Is the relative value of the spectral reflectance of the reference object rs (λ) (= αR
s (λ)) is calculated.

The proportional coefficient calculating unit 54 calculates the proportional coefficient α by dividing the calculated relative value rs (λ) by the known Rs (λ). The spectral reflectance absolute value calculation unit 55 uses the calculated proportional coefficient α for the relative value r (λ) (= αR (λ)) of the spectral reflectance of the subject 1 calculated by the spectral reflectance calculation unit 53. By removing the absolute value R of the spectral reflectance of the subject 1.
Calculate (λ).

According to this structure, the object color measuring apparatus of the present invention configured as shown in FIG. 11 realizes the object color measuring method of the present invention according to the processing flow of FIG.

FIG. 12 shows an embodiment of the object color measuring apparatus of the present invention which realizes the object color measuring method of the present invention according to the processing flow of FIG.

The object color measuring device of the present invention according to this embodiment has a structure in which the control / calculation device 5 includes an external light spectral distribution calculating section 56 in addition to the structure shown in FIG.

The external light spectral distribution calculating unit 56 receives e ₀ (λ) or e ₁ (λ) from the illumination light interpolating spectral distribution calculating unit 51, and F ₀ (λ) or E ₀ (λ) from the subject interpolating spectral distribution calculating unit 52. F ₁ (λ) is received, α is received from the proportional coefficient calculation unit 54, the absolute value R (λ) of the spectral reflectance of the subject 1 is received from the spectral reflectance absolute value calculation unit 55, and E (λ) = [ F ₀ (λ) / R (λ)] − αe ₀ (λ) is added to the received e ₀ (λ), F ₀ (λ), α, R
Calculate the spectral distribution E (λ) of outside light by substituting (λ), or use the formula E (λ) = [F ₁ (λ) / R (λ)] − αe ₁ (λ) E ₁ (λ), F ₁ (λ), α, R
The spectral distribution E (λ) of external light is calculated by substituting (λ).

According to this structure, the object color measuring apparatus of the present invention configured as shown in FIG. 12 realizes the object color measuring method of the present invention according to the processing flow of FIG.

FIG. 13 shows an embodiment of the object color measuring apparatus of the present invention which realizes the object color measuring method of the present invention according to the processing flow of FIG.

The object color measuring apparatus of the present invention according to this embodiment is the object spectroscopic distribution measuring apparatus 1 shown in FIG.
As a specific device of No. 4, a configuration using the spectral image capturing device 16 is adopted.

The spectral image capturing device 16 has a function of simultaneously or instantaneously measuring the spectral luminous intensity distributions F (λ) of a plurality of points on the subject 1.

For example, the spectroscopic image capturing device 16 reads image data of one line of the subject 1 through a slit, and spectrally analyzes the data of each pixel forming the image data using a prism or a grating. An apparatus is used which can measure the spectrophotometric distribution F (λ) of each point of the subject 1 located on the line by reading the two-dimensional image sensor at one time.

Further, as the spectral image photographing device 16,
In front of the two-dimensional image sensor, a plurality of optical filters having different spectral transmittances are rotatably arranged at high speed, or an optical filter capable of electronically changing the spectral transmittance is arranged, thereby An apparatus is used that can instantaneously measure the spectral luminous intensity distribution F (λ) at each point.

According to this structure, the object color measuring apparatus of the present invention configured as shown in FIG. 13 realizes the object color measuring method of the present invention according to the processing flow of FIG.

[0117]

As described above, according to the present invention,
Since it becomes possible to measure the spectral reflectance of a subject by measuring or photographing the subject only once without being affected by external light, a subject that moves at a high speed, which was difficult with the conventional technology. It becomes possible to measure the spectral reflectance and the object color. Then, it becomes possible to measure the spectral reflectance and the object color of the subject from the high-speed moving body.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an arrangement example of main constituent elements of the present invention.

FIG. 2 is an exemplary embodiment of a processing flow for realizing the present invention.

FIG. 3 is an explanatory diagram of a spectral transmittance of a filter.

FIG. 4 is an explanatory diagram of a spectral distribution of illumination light.

FIG. 5 is an explanatory diagram of a spectral luminous intensity distribution of a subject.

FIG. 6 is an explanatory diagram of interpolation processing.

FIG. 7 is another embodiment of the processing flow for realizing the present invention.

FIG. 8 is another embodiment of the processing flow for realizing the present invention.

FIG. 9 is another embodiment of the processing flow for realizing the present invention.

FIG. 10 is an embodiment of an object color measuring device of the present invention.

FIG. 11 is another embodiment of the object color measuring device of the present invention.

FIG. 12 is another embodiment of the object color measuring device of the present invention.

FIG. 13 is another embodiment of the object color measuring device of the present invention.

[Explanation of symbols]

1 subject 2 light sources 3 filters 4 Spectral distribution measurement device 5 Control and arithmetic unit 10 Light source light generator 11 Illumination light generator 12 Illumination spectral distribution measuring device 13 Measurement control unit A 14 Subject spectrophotometric distribution measuring device 15 Measurement control unit B 16 Spectral imager 50 arithmetic control unit 51 Illumination light interpolation spectral distribution calculation unit 52 Subject Interpolation Spectral Distribution Calculation Unit 53 Spectral reflectance calculator 54 Proportional coefficient calculator 55 Spectral reflectance absolute value calculator 56 external light spectral distribution calculation unit

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-8-320282 (JP, A) JP-A-7-35615 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01J 3/00-3/51 G01N 21/00-21/01 G01N 21/17-21/61

Claims (10)

(57) [Claims] 1. A subject object illuminated by external light
In the object color measuring method for measuring color, Between the wavelength range where the light intensity is strong and the weak wavelength rangeIn the wavelength direction
Generates illumination light with spectral characteristics that appear repeatedly.
The process of It is not necessary to calculate or measure the spectral distribution e (λ) of the illumination light.
And The portion of the subject illuminated by both external light and the illumination light
The process of measuring the luminous intensity distribution F (λ), From e (λ), only the wavelength region where the intensity of the light is strong
Spectral distribution e interpolated in the extraction wavelength direction₁(λ), and
Extract only the wavelength region where the light intensity is weak in the wavelength direction
Interpolated spectral distribution e₀the process of calculating (λ), From F (λ), only the wavelength region where the intensity of the light is strong
Spectral intensity distribution F interpolated in the extraction wavelength direction₁(λ),
And extracting only the wavelength range where the light intensity is weak
Spectral intensity distribution F interpolated in the direction₀the process of calculating (λ), Said e₀(λ), e₁(λ), F₀(λ), F₁using (λ)hand, r (λ) = [F ₁ ( λ ) -F ₀ ( λ ) ] / [E ₁ ( λ ) -E
₀ ( λ ) ] Based on the calculation formula Relative value of spectral reflectance of image
and a step of calculating r (λ), Characteristic object color measurement method. 2. The object color measuring method according to claim 1, wherein a filter having a spectral transmission characteristic such that a wavelength region having a high light transmittance and a wavelength region having a low light transmittance appear repeatedly in the process of generating illumination light. An object color measuring method characterized in that illumination is generated by filtering light from a light source. 3. The object color measuring method according to claim 1 or 2, wherein a reference object whose absolute value Rs (λ) of spectral reflectance is known is arranged at an observation position of a subject, and the r (λ) is obtained. Using the same procedure as described above, the relative value rs (λ) of the spectral reflectance of the reference object is calculated, and the proportional coefficient α of the Rs (λ) and the rs (λ) is calculated. And a step of calculating the absolute value R (λ) of the spectral reflectance of the subject by converting the r (λ) using the object color measuring method. 4. The object color measuring method according to claim 3, wherein a relational expression E is established among the F ₀ (λ), the e ₀ (λ), the α, the R (λ), and external light. (Λ) = [F ₀ ( λ ) / R (λ)] − αe ₀ ( λ ) or F ₁ (λ), e ₁ (λ), α, R (λ), and external light And a step of calculating a spectral distribution E (λ) of external light from a relational expression E (λ) = [F ₁ ( λ ) / R (λ)] − αe ₁ ( λ ) Characteristic object color measurement method. 5. The object color measuring method according to claim 1, wherein in the process of measuring the spectral luminous intensity distribution F (λ) of the subject, a spectral image of the subject is photographed, An object color measuring method characterized by measuring a spectral luminous intensity distribution F (λ) at each point of an object which is a measuring point of the object color. 6. A subject object illuminated by external light
In an object color measuring device that measures color, Between the wavelength range where the light intensity is strong and the weak wavelength rangeIn the wavelength direction
Generates illumination light with spectral characteristics that appear repeatedly.
Illumination light generating means, An illumination for calculating or measuring the spectral distribution e (λ) of the illumination light.
Bright spectral distribution acquisition means, The portion of the subject illuminated by both external light and the illumination light
Subject spectral luminous intensity distribution measurement for measuring luminous intensity distribution F (λ)
Means and From e (λ), only the wavelength region where the intensity of the light is strong
Spectral distribution e interpolated in the extraction wavelength direction₁(λ), and
Extract only the wavelength region where the light intensity is weak in the wavelength direction
Interpolated spectral distribution e₀Illumination light interpolation spectral component to calculate (λ)
Cloth calculation means, From F (λ), only the wavelength region where the intensity of the light is strong
Spectral intensity distribution F complemented in the extraction wavelength direction₁(λ),
And extracting only the wavelength range where the light intensity is weak
Complementary spectral distribution F₀Subject compensation for calculating (λ)
Inter-spectral distribution calculation means, Said e₀(λ), e₁(λ), F₀(λ), F₁using (λ)hand, r (λ) = [F ₁ ( λ ) -F ₀ ( λ ) ] / [E ₁ ( λ ) -E
₀ ( λ ) ] Based on the calculation formula Relative value of spectral reflectance of image
and a spectral reflectance calculating means for calculating r (λ).
To Characteristic object color measuring device. 7. The object color measuring device according to claim 6, wherein the illumination light generating means uses a filter having a spectral transmission characteristic such that a wavelength region having high light transmittance and a wavelength region having low light transmittance appear repeatedly. An object color measuring device characterized by generating illumination by filtering light from a light source. 8. The object color measuring device according to claim 6, wherein the subject spectrophotometric distribution measuring means has a known absolute value Rs (λ) of the spectral reflectance arranged at the observation position of the subject. By measuring the spectral luminosity distribution of the object, the spectral reflectance calculation means causes the relative value r of the spectral reflectance of the reference object.
s (λ) is calculated, and a proportional coefficient calculating means for calculating a proportional coefficient α between the Rs (λ) and the rs (λ); and the r (λ) is converted using the α. Accordingly, the object color measuring device is provided with a spectral reflectance absolute value calculating means for calculating the absolute value R (λ) of the spectral reflectance of the subject. 9. The object color measuring device according to claim 8, wherein a relational expression E that is established among the F ₀ (λ), the e ₀ (λ), the α, the R (λ), and outside light. (Λ) = [F ₀ ( λ ) / R
(Λ)] − αe ₀ ( λ ) or the above F ₁ (λ) and the above e
_From the relational expression E (λ) = [F ₁ ( λ ) / R (λ)] − αe ₁ ( λ ) , which holds between ₁ (λ), α, R (λ), and external light, An object color measuring device characterized by comprising an external light spectral distribution calculating means for calculating a spectral distribution E (λ) of light. 10. The object color measuring device according to claim 6, wherein the subject spectrophotometric distribution measuring means captures a spectroscopic image of the subject to obtain object color measuring points. An object color measuring device characterized by measuring a spectral luminous intensity distribution F (λ) for each point of a subject.