JPH11132853A - Color characteristic measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color characteristic measuring device that is in a simple configuration by the configuration of a conventional stimulus value direct- reading method without using any spectroscope and can obtain the color characteristics of a light source from the spectral distribution of the light source inexpensively. SOLUTION: A measuring device has a plurality of filters 1 separately arranged at the path of emission light from a light source to be measured, a plurality of sensors 2 that are provided corresponding to the filters 1 and receive light through the filters 1, an A/D converter 5 for converting the output of the sensor 2 from analog to digital, and an interface 6 for outputting sensor data being converted by the A/D converter 5 toward the outside. Then, the spectral transmittance of a plurality of filters 1 are set so that the spectral distribution of the light source to be measured can be estimated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color characteristic measuring device for measuring a spectral distribution of a light source and an object color.

[0002]

2. Description of the Related Art FIG. 11 is a block diagram of a color characteristic measuring apparatus according to a conventional stimulus value direct reading method. In FIG. 11, 3 is a current / voltage / conversion amplifier (hereinafter simply referred to as an amplifier), 4 is a selector, 5 is an A / D converter, 6 is an interface, and 14 is an optical filter (hereinafter simply referred to as a filter). Reference numeral 15 denotes an optical sensor (hereinafter simply referred to as a sensor).

Next, the operation will be described. The spectral transmittance of the filter 14 and the spectral sensitivity of the sensor 15 shown in FIG. 11 must be designed in advance so that the spectral product of the filter 14 and the sensor 15 matches the color matching function as shown in, for example, JIS Z8724. Must. The light applied to each filter passes through the filter 14 and passes through the sensor 1
5 is input. The sensor 15 generates a current corresponding to the input light amount, the current value is converted into a voltage by the amplifier 3, and is input to the A / D converter 5 via the selector 4.
The A / D converted sensor data is sent to an external computer or the like via the interface 6. An external computer calculates color characteristics from the sensor data.

In such a color characteristic measuring apparatus using the stimulus value direct reading method, it is necessary to approximate the spectral responsivity by a combination of a filter and a sensor to a color matching function.
In addition, since only the tristimulus values XYZ can be obtained, it was necessary to measure using a spectrophotometer by a spectrophotometric method in order to increase the accuracy. Also, spectrophotometers are generally expensive and often very large in structure.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a simple structure using a conventional stimulus value direct reading method without using a spectroscopic device or the like. In addition, it is an object of the present invention to provide a colorimetry device capable of obtaining the color characteristics of the light source from the spectral distribution of the light source at low cost.

It is a further object of the present invention to provide a color characteristic measuring device capable of obtaining the color characteristics of an object by providing a light source in the color characteristic measuring device.

[0007]

A chromaticity measuring apparatus according to the present invention is provided with a plurality of filters arranged separately on a path of light emitted from a light source to be measured, and provided for each filter. A plurality of sensors for receiving the passed light;
An A / D converter for A / D converting the output of the sensor;
An interface for outputting the sensor data converted by the converter to the outside is provided, and the spectral transmittances of the plurality of filters are set so that the spectral distribution of the light source to be measured can be estimated.

A plurality of filters selectively disposed in a path of light emitted from the light source to be measured; a plurality of sensors provided corresponding to the selected filters to receive light passing through the filters; A / D that A / D converts the output of
A converter and an interface for outputting the sensor data converted by the A / D converter to the outside are provided, and the spectral transmittances of the plurality of filters are set so that the spectral distribution of the light source to be measured can be estimated. .

Further, in place of the optical filter, an optical sensor having a spectral sensitivity set to the spectral product of the spectral transmittance of the optical filter and the spectral sensitivity of the optical sensor is used. The light source to be measured is a light source for measuring the color of an object, and can measure the reflected light of the object to be measured.

Further, the filter is provided between the light source and the object to be measured. Further, instead of the optical filter, a plurality of light sources having a spectral distribution set to the spectral product of the spectral transmittance of the plurality of optical filters and the spectral distribution of the light source are used. In addition, the apparatus includes a microprocessor for calculating the spectral characteristics and color characteristics of the light source to be measured from the sensor data, and a display device having a function of displaying the calculation results.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a configuration diagram showing a first embodiment of a color characteristic measuring device according to the present invention. In FIG. 1, 1
Is a plurality of optical filters having different spectral transmittances (hereinafter simply referred to as filters), 2 is an optical sensor such as a photodiode (hereinafter simply referred to as a sensor), and 3 to 6 are the same as the conventional ones shown in FIG. Description is omitted because there is.

In the color characteristic measuring apparatus thus configured, the light emitted from the light source to be measured passes through a plurality of filters 1 having different spectral transmittances and is applied to sensors 2 corresponding to the respective filters. The output of each sensor is converted from a current value to a voltage value by the amplifier 3 and the A / D converter 5
Is amplified to a voltage value corresponding to the input. A / D converter 5
The data A / D converted in step (1) is sent from the interface 6 to an external computing device such as a computer. The computer calculates the spectral distribution and color characteristics of the measured light source from the received data. Here, the spectral transmittances of the plurality of filters 1 are set such that the difference between the estimated value and the measured value of the spectral distribution of the plurality of sample light sources similar to the light source to be measured is minimized.
Further, the estimated value can be calculated from the output value of the sensor.

For example, the outputs Sn = (S
1, S2, S3,..., Sn) is a spectral distribution Em = (E
1, E2, E3... Em), when the following equation (1) G · Em = Sn (1) is obtained, the matrix H for obtaining the measured light source E ′ estimated from the sensor output Sn is It is determined by the following equation (2). H · Sn = E′m (2) When the number of filters is represented by n and the measurement wavelength range is represented by m discrete data, the matrix G represents the spectral transmittance Fn (m) of the filter and the spectral sensitivity C of the sensor. (M) is represented by the determinant shown in FIG. For example, assuming a band-pass filter having a Gaussian distribution, the filter has a center wavelength and a half width as parameters, but the filter has an arbitrary shape and the parameter may be arbitrary. . Next, a plurality of sample light sources having a spectral distribution very similar to the light source to be measured are prepared, and the output Sn is calculated from equation (1). The matrix H can be obtained from the calculated Sn and the spectral distribution Em of the sample light source as a generalized inverse matrix of G. H · Sn = Em H · Sn · Snt / (Sn · Snt) = Em · Snt /
(Sn · Snt) If Snt is the transposed matrix of Sn, Sn · Snt / (Sn
Snt) is a unit matrix and can be deleted. Therefore H
Is determined by the following equation. H = Em · Snt / (Sn · Snt) From the obtained H and the calculated Sn, the spectral distribution E′m of the light source to be measured can be estimated from Expression (2).

Next, a procedure for obtaining the spectral transmittance of the filter will be described with reference to a data flow diagram shown in FIG. First, from the spectral distribution E of the actually measured sample data, a sensor output Sn when a filter is measured using a temporarily determined conversion matrix G is obtained. Further, an estimated value E ′ of the spectral distribution of the sample is calculated using an estimation matrix H obtained in advance from the sensor output Sn. Next, the measured value E and the estimated value E 'of the sample are compared to determine whether or not the required accuracy has been reached. If the required accuracy has not been reached, the same operation is repeated using the transformation matrix G in which the parameters of the filter have been changed. Then, the spectral transmittance of the filter when the required accuracy is reached is determined as the filter for measuring the light source to be measured. If the measurement is performed using the filter obtained by the above process, the spectral reflectance of the measured light source can be estimated from the sensor data by the equation (2). In such a configuration, since the filter 1 is set so that the deviation between the measured value and the estimated value of the sample is minimized, the spectral characteristics can be estimated with high accuracy.

Embodiment 2 FIG. 4 is a block diagram showing a second embodiment of the present invention. As shown in FIG.
By installing the CPU 7 on the output side of the CPU and attaching the display device 8 to the CPU, the color characteristic data is calculated by the microprocessor from the data obtained from the A / D converter, and the calculation result is displayed on the display device. It was done.

Embodiment 3 FIG. 5 is a block diagram showing a third embodiment of the present invention. As shown in FIG. 5, the filter 1 is attached to a rotating plate 9 to measure one filter and then rotate the filter to the next filter. It is configured to repeat the measurement. With this configuration, the filter 1 can be easily replaced, and only one sensor 2 is required, so that the device is inexpensive.

Embodiment 4 FIG. 6 is a block diagram showing a fourth embodiment of the present invention. As shown in FIG. 6, a sensor 10 is installed in accordance with the spectral product of the sensitivity of the sensor combining the filter and the sensor and the transmittance of the filter. . With this configuration, the light emitted from the light source to be measured is directly input to the sensor, and the color characteristics are measured.

Embodiment 5 FIG. 7 is a block diagram showing a fifth embodiment of the present invention. By providing an illumination light source 11 as shown in FIG. 7, light emitted from the illumination light source 11 is reflected by an object to be measured 12 and passes through a filter 1. To the sensor 2. Since the spectral distribution obtained from the output of the sensor 2 is the spectral product of the spectral distribution of the illumination light source 11 and the spectral reflectance of the measured object 12, the spectral distribution of the measured light source is divided by the spectral distribution of the illumination light source measured in advance. The reflectance can be determined. With this configuration, if the spectral distribution of the illumination light source is known, the color characteristics of the object can be measured by measuring the light after reflection and comparing it with the light before reflection.

Embodiment 6 FIG. FIG. 8 is a block diagram showing a sixth embodiment of the present invention. As shown in FIG. 8, the light emitted from the illumination light source 11 is reflected by the measured object 12 and the After measuring with one filter, the filter is rotated to the next filter and the measurement is repeated. With this configuration, the filters can be easily exchanged, and the color sensor can be sequentially measured for each filter to use a single sensor. Further, the spectral reflectance of the light source to be measured can be obtained in the same manner as in the fifth embodiment.

Embodiment 7 FIG. 9 is a block diagram showing a seventh embodiment of the present invention. As shown in FIG. 9, by installing a rotating plate 9 between an object to be measured 12 and an illumination light source 11, the light of the illumination light source 11 is filtered. 1 and is reflected on the object to be measured and input to the sensor. After measuring with one filter, the filter is rotated to the next filter and the measurement is repeated. With this configuration, it is easy to replace the filter and the light applied to the object to be measured becomes light that has passed through the filter, and unnecessary light can be removed. Deterioration can be prevented.

Embodiment 8 FIG. FIG. 10 is a block diagram showing an eighth embodiment of the present invention. As shown in FIG. 10, the spectral distributions of the illumination light sources corresponding to the number of filters are set to the spectral transmittance of each filter and the spectral product of the spectral distribution of the light source. Light source 13
Is installed, and the light source 13 is turned on one by one to measure the color characteristics by performing the measurement. Since the emitted light of the light source becomes the same as the light passing through the filter, the filter can be omitted. .

[0022]

As described above, according to the present invention, since the filter is set so that the deviation between the measured value and the estimated value of the sample is minimized, the color by the conventional stimulus value direct reading method without using a spectroscope. Highly accurate spectral characteristics can be obtained with the same configuration as the characteristic measuring device.

Further, since the filter can be replaced, only one sensor can be used, so that the apparatus can be constructed at low cost. Further, since the sensor is provided in accordance with the spectral product of the sensitivity of the sensor and the transmittance of the filter, the filter is not required, the configuration of the apparatus is simplified, and the apparatus can be configured at low cost.

Further, by installing a light source and measuring the reflected light of the object to be measured, the color characteristics of the object can be measured. Further, by disposing the filter between the light source and the object to be measured, unnecessary light does not hit the object to be measured, and deterioration of the object to be measured by the light source can be prevented.

Further, since the spectral characteristic of the light source is set to the spectral product of the spectral transmittance of the filter and the spectral sensitivity of the sensor, the filter becomes unnecessary, the configuration of the apparatus is simplified, and the apparatus can be constructed at low cost. Further, since an arithmetic device and a display device for calculating color characteristics are provided, an external arithmetic device is not required, and the device can be used alone.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a data flow diagram showing a procedure for obtaining a filter according to the first embodiment.

FIG. 3 is a diagram showing a transformation matrix according to the first embodiment.

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

FIG. 5 is a configuration diagram showing a third embodiment of the present invention.

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

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

FIG. 8 is a configuration diagram showing a sixth embodiment of the present invention.

FIG. 9 is a configuration diagram showing a seventh embodiment of the present invention.

FIG. 10 is a configuration diagram showing an eighth embodiment of the present invention.

FIG. 11 is a view showing a conventional color specification measuring apparatus of this type.

[Explanation of symbols]

1 filter, 2 sensors, 3 amplifiers, 4 selectors, 5 A / D converter, 6 interface, 7 C
PU, 8 display device, 9 rotating plate, 10 sensor incorporating characteristics of filter, 11 illumination light source, 12 measured object, 13 light source, 14 filter.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshikuni Nishimura 2-5-1 Inaji, Amagasaki-shi, Hyogo Mitsubishi Electric Microcomputer Equipment Software Co., Ltd. No.1 Mitsubishi Electric Microcomputer Equipment Software Co., Ltd.

Claims (7)

[Claims] 1. A plurality of optical filters respectively arranged in a path of light emitted from a light source to be measured, and a plurality of optical sensors provided corresponding to each of the optical filters and receiving light passing through the optical filters. And the output of the optical sensor is A /
An A / D converter for D-conversion and an interface for outputting the sensor data converted by the A / D converter to the outside are provided, and the spectral transmittances of the plurality of optical filters can estimate the spectral distribution of the light source to be measured. A color characteristic measuring device characterized by being set as follows. 2. A plurality of optical filters selectively disposed in a path of light emitted from a light source to be measured, and a plurality of optical filters provided corresponding to the selected optical filters and receiving light passing through the optical filters. An optical sensor, an A / D converter for A / D converting an output of the optical sensor, and an interface for outputting the sensor data converted by the A / D converter to the outside; A color characteristic measuring device, wherein a transmittance is set so that a spectral distribution of a light source to be measured can be estimated. 3. The optical sensor according to claim 1, wherein an optical sensor having a spectral sensitivity set to a spectral product of a spectral transmittance of the optical filter and a spectral sensitivity of the optical sensor is used instead of the optical filter. 2. The color characteristic measuring device according to 2. 4. The device according to claim 1, wherein the light source to be measured is a light source for measuring an object color, and is capable of measuring reflected light of the object to be measured. The color characteristic measuring device described in the above. 5. The color characteristic measuring apparatus according to claim 4, wherein the optical filter is provided between the light source and the object to be measured. 6. A method according to claim 4, wherein a plurality of light sources having a spectral distribution set to a spectral product of a spectral transmittance of the plurality of optical filters and a spectral distribution of the light source are used in place of the optical filters. Color characteristic measuring device. 7. The apparatus according to claim 1, further comprising a microprocessor for calculating the spectral characteristics and color characteristics of the light source to be measured from the sensor data, and a display device having a function of displaying the calculation results. The color characteristic measuring device according to claim 1.