JPH05203495A - Color meter and color measuring method for color meter - Google Patents

Abstract

PURPOSE:To enable easily obtaining highly reliable measurement data without touching even in an environment insufficient disturbance light insulation. CONSTITUTION:With a detection head 20 as a sample measuring means arranged untouching state to a measured sample 1, reflection light intensity data of the measured sample 1 is detected. Also with a detection head 30 as a disturbance measuring means, reflection light intensity data only by the disturbance light is detected and the color spectrum reflection light intensity data of the measured sample is corrected with the color spectrum reflection light intensity data of the disturbance light to get the reflectivity. Thus exact data equivalent to the data obtained by using a black box to insulate disturbance light is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colorimeter for calculating a colorimetric value of a measurement sample based on reflected light from the measurement sample and a colorimetric method of the colorimeter.

[0002]

2. Description of the Related Art In a general colorimeter, a measurement sample is illuminated by a light source, and light reflected and diffused on the surface of the measurement sample is received by a photoelectric conversion element (hereinafter referred to as "sensor") to reflect the measurement sample. Measuring light intensity data.

When measuring the color of a sample to be measured with a colorimeter that requires particularly high precision, first, a standard white plate made of ceramics, barium sulfate or the like is approximated to a perfect diffusing surface is irradiated with measuring light, and the standard white plate is measured. Obtain the color separation reflected light amount data. Then, the measurement sample is irradiated with the measurement light to similarly obtain the color separation reflected light amount data of the measurement sample. Then, the ratio of the reflected light amount data of the measurement sample to the color separation reflected light amount data of the standard white plate is calculated, and the colorimetric value of the measurement sample is obtained from the ratio.

In order to obtain accurate data, a sensor for directly monitoring the light quantity of the light source is provided to correct the measurement data, and the light quantity of the light source changes due to the creep of the power supply voltage or a momentary voltage change, or AC lighting. Therefore, measures are taken to remove the influence of light intensity ripple that cannot be avoided.

Further, in the conventional device, a dark box is used for the light receiving portion to prevent mixing of ambient light with the illumination light,
Improves reliability of measurement data. When a dark box is used, the sample to be measured is placed in the dark box, or the sample is brought into close contact with the opening (measurement window) of the dark box.

[0006]

However, it takes time and effort to store the measurement sample in the dark box as described above.
There is a problem that work efficiency is low. Further, for a measurement sample having a large size, the dark box becomes large, and the dark box cannot be applied to a measurement sample having a continuous shape such as a print cloth or a printed matter on roll paper.

On the other hand, when the measurement sample is brought into close contact with the opening (measurement window) of the dark box, there is an advantage that the measuring head can be downsized, but the opening of the dark box directly or indirectly with the measurement sample. There is a problem that it is impossible to perform non-contact measurement because the structure is in contact with.

[0008] In other words, in today's various automated and labor-saving lines, it is necessary to perform quality control such as identifying and inspecting a work during each process. There is a demand for a colorimeter that can measure color without performing the measurement. This is because it is extremely difficult to block ambient light from the non-contact colorimeter in a normal environment.

Therefore, the present invention provides a non-contact type colorimeter and a colorimeter that can easily obtain highly reliable measurement data even in an environment where the blocking of ambient light is insufficient. The purpose is to provide a color method.

[0011]

To achieve the above object, a colorimeter according to the present invention comprises a light source device for emitting measuring light to a measuring sample, a detection head for receiving reflected light from the measuring sample, and this detection. In a colorimeter provided with a main body device that receives a measurement signal output from the head and executes a predetermined calculation to calculate a colorimetric value of the measurement sample, the detection head is isolated from the measurement sample for a predetermined period of time. While being placed in contact, the detection head is provided with a sample measuring unit that receives the reflected light from the measurement sample together with the ambient light, and a disturbance measuring unit that receives only the ambient light. Is provided with an arithmetic unit for correcting the measurement signal output from the sample measuring means of the detection head with the measurement signal output from the disturbance measuring means to calculate the colorimetric value excluding the influence of the disturbance light. Has a configuration was.

Further, in the colorimetric method of the colorimeter according to the present invention, the detection head receives the reflected light of the measurement light irradiated and reflected on the measurement sample, and the color of the measurement sample is expressed based on the output signal from the detection head. In the colorimetric method of the colorimeter for calculating the value, the detection head is placed in a non-contact state with being separated from the measurement sample for a predetermined period, and then the detection head is used to measure a measurement sample including ambient light. Only reflected light and ambient light are received separately, and the output signal from the reflected light from the measurement sample containing ambient light is corrected by the output signal from only ambient light to calculate the colorimetric value by removing the influence of ambient light. It has such a structure.

[0013]

In the colorimeter and the colorimetric method of the colorimeter having such a configuration, the detection head is arranged in a non-contact state with respect to the measurement sample, and the detection head arranged in the non-contact state causes disturbance light. The reflected light amount data of the measurement sample mixed with and the reflected light amount data of only the ambient light are detected separately. Then, by shifting the color-separated reflected light amount data of the measurement sample by the reflected-light amount data of only the ambient light, the influence of the ambient light is removed, and then the color-separated reflectance data is calculated. The color-separated reflectance data thus obtained is equivalent to the data obtained by blocking the ambient light by using the conventional dark box, and can be obtained as accurate data.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. As shown in FIG. 1, the device according to the present invention includes a light source device 10 and a pair of detection heads 20 and 3.
0 and a main body device 40. Light source device 1
At 0, the constant voltage A is applied to the incandescent lamp 11 which is the light source.
A lamp power source 12 such as a C power source is connected, and a condenser 13 is provided in front of the incandescent lamp 11 with a predetermined space therebetween. This capacitor 13
Is a collimating lens 13a composed of an aspherical lens having a strong power, and a one-sided convex condenser lens 1 acting as an auxiliary.
3b and.

A filter 14 for blocking heat rays is arranged on the front side (on the right side in the drawing) of the condenser 13 on the optical axis, and a beam splitter 15 made of a flat glass is arranged.
Are arranged. The filter 14 is made of a flat glass or a heat ray absorbing glass having a heat ray reflective multilayer filter, reflects or absorbs heat rays in the infrared region, transmits only visible light, and is a sample to be measured (hereinafter referred to as a measurement sample. 1) has a function of preventing the temperature rise.

An incident end 18a of the optical cable 18 is fixedly arranged on the optical axis front side (right side in the figure) of the horizontal light flux of the two light fluxes of the horizontal light flux and the vertical light flux divided by the beam splitter 15. The optical cable 18 is composed of an optical fiber bundle and has the above-mentioned incident end 1
The horizontal luminous flux is received by 8a. On the other hand, on the optical axis of the vertical light flux on the other side divided by the beam splitter 15, a monitor 16 including an optical sensor for receiving the vertical light flux is arranged, and this monitor 16 is also provided.
In addition, a preamplifier 17 is attached.

Both sides of the flat glass constituting the beam splitter 15 are coated with an antireflection film for reducing the reflectance to about 1 to 2%, and the monitor 16 is also provided by this antireflection film. When the amount of light incident on is too large, a neutral density filter (not shown) is arranged in front of the monitor 16.

The monitor 16 converts the incident light from the incandescent lamp 11 into an electric signal proportional to the amount of light, and the electric signal output from the monitor 16 is amplified and impedance-converted in the preamplifier 17. After that, it is output to the main body device 40 as a reference signal REF.

On the other hand, the detection head 20 constitutes a sample measuring means, and comprises a light projecting section 21 and a light receiving section 22. Of these, the light projecting portion 21 is provided with an emitting end 18b of the optical cable 18, and an irradiation lens 23 is provided so as to face the emitting end 18b of the optical cable 18. The irradiation lens 23 is
It collects the light emitted from the emission end 18b of the optical cable 18 and is arranged so as to be separated from the measurement sample 1 by a predetermined distance and forms an inclination angle of about 45 degrees with respect to the surface of the measurement sample 1. It has an optical axis. The converged light from the irradiation lens 23 irradiates a range in the vicinity of the measurement range 2 of the measurement sample 1, and the reflected light is received by the light receiving unit 22 as diffuse reflected light instead of specular reflected light. There is. The reflected light from the measurement sample 1 is mixed with ambient light at the place where the measurement sample 1 is set, that is, natural light or light from a fluorescent lamp or the like.

On the other hand, the light receiving section 22 of the detection head 20 has an optical axis substantially vertical to the surface of the measurement sample 1, and the imaging lens 24, the diaphragm plate 25 and the color sensor 26 are located on the optical axis. Are sequentially arranged from the measurement sample 1 side.
An aperture 25a is provided in the diaphragm plate 25, and reflected light from a portion of the measurement sample 1 corresponding to the measurement range 2 is incident on the color sensor 26 through the aperture 25a. ..

The color sensor 26 is of a tristimulus value type, and three photosensors are provided in close contact on the same substrate, and the front surface of each of these photosensors is
A color separation filter for each color corresponding to the tristimulus value is arranged. And from each of these optical sensors, CIE
(International Illumination Commission) 1931 double field of view or C
A light amount signal color-separated by being matched with the tristimulus values of the XYZ color system based on the 10-degree visual field by IE1964 is output.

Further, the color sensor 26 is provided with a preamplifier group 27 for amplifying and impedance-converting the light amount signals emitted from the respective optical sensors. The output signal from the preamplifier group 27 is the main device 40.
Is being applied to.

The other detecting head 30 provided adjacent to the detecting head 20 constitutes a disturbance measuring means, and is provided with only the light receiving section 32, and the position directly below the light receiving section 32. A standard white plate 3 is arranged at a predetermined distance from each other. The standard white plate 3 is made by approximating ceramics, barium sulfate or the like to a perfect diffusing surface, and the standard white plate 3 is not irradiated with light from a specific light source. Alternatively, ambient light such as a fluorescent lamp is emitted. The disturbance diffused light reflected by the standard white plate 3 is received by the light receiving section 32.

The light receiving section 32 of the detection head 30 has an optical axis substantially perpendicular to the surface of the standard white plate 3.
An imaging lens 34, a diaphragm plate 35, and a color sensor 36 are sequentially arranged on the optical axis from the standard white plate 3 side. The aperture plate 35 is provided with an aperture 35a, and the reflected light from the standard white plate 3 is incident on the color sensor 36 through the aperture 35a.

The color sensor 36 is similar to the one provided in the detection head 20 described above, and is additionally provided with a preamplifier group 37, and an output signal from the preamplifier group 37 is a main unit 40. Is being applied to.

The main body device 40 comprises a signal processing unit 41 and a display unit 42, and the signal processing unit 41 controls the entire system of the colorimeter by a CPU (central processing unit) 43.
And an amplifier group 44, an MPX (multiplexer) 45, and an A / D converter 46.

The CPU 43 has an RO (not shown).
M, RAM, reference clock oscillator, counter, etc. are built in. The reference clock signal output from the reference clock oscillator is counted up by the counter, and when the count value reaches the count value corresponding to the preset period of the measurement clock, the counter is cleared and 1 is thus generated. "1" according to each clock
A series of select signals that sequentially change from "7" to "7" and return to "0" are output to the MPX 45.

Further, the MPX 45 has color separation signals X, Y, Z of the measurement sample reflected light outputted from the detection head 30, and disturbance light color separation signals X ', outputted from the detection head 40.
The reference signals REF from Y ′ and Z ′ and the light source device 10 are constantly input through each amplifier of the amplifier group 44. As described above, the color separation signals X, Y, Z of the measurement sample reflected light and the color separation of the ambient light are corresponding to the selection signal of "0" sequentially changing from "1" to "7". Signals X ', Y
Either ', Z', or the reference signal REF is selected, and A /
It is input to the D converter 46. The A / D converter 46 has a function of converting each analog signal input from the MPX 45 into digital data and outputting the digital data to the CPU 43.

In the CPU 43, sequentially input digital data of the signals X, Y, Z, X ', Y', Z ', and REF are temporarily stored in the RAM, and the color separation signal X of the reflected light of the measurement sample is stored. , Y, Z digital data are calculated by the digital data of the color separation signals X ′, Y ′, Z ′ of the ambient light, and then normalized by the digital data of the reference signal REF. A set of color separation measurement data x, y, z obtained by normalizing is stored in the RAM. The measurement cycle for obtaining such a set of color separation measurement data x, y, z is executed every time the clock is generated, and the measurement data is accumulated.

As described above, the color-separated measurement data x, y, z normalized as described above is corrected for the light amount change of the incandescent lamp 11, that is, the light creep for a long time or the instantaneous light amount ripple, so that the light amount change is obtained. The data is equivalent to the data obtained using a light source having no light and is corrected and shifted over a portion corresponding to the influence of ambient light, so that the measurement data is accurate.

When color measurement is performed by the apparatus of this embodiment, first, the main routine shown in FIG. 2A is started and the standard white plate 3 and the measurement sample 1 are set. The color measurement by the detection head 30 that constitutes the measurement means and the detection head 20 that constitutes the sample measurement means
It is executed based on the measurement subroutine.

In the measurement subroutine shown in FIG. 2B, first, the content of the measurement counter for counting the number of times of measurement is cleared (C = 0) to enter the measurement cycle, and the CPU 4
The clock from 3 is awaited.

When the clock is input, as described above, digital data of the signals X, Y, Z, X ', Y', Z ', and REF of each set sample are temporarily stored in the RAM. Digital data of the color separation signals X, Y, Z of the reflected light of the measurement sample stored by the digital data of the color separation signals X ', Y', Z'of the ambient light, and then the digital reference signal REF. Normalized by data. A set of color separation measurement data x, y, z obtained by normalization is stored in the RAM, and the measurement counter is incremented to determine whether the content C has reached a preset number of times K of measurement. It

If the content C has not reached K, the clock standby state is returned, and if C = K, the RAM is returned.
The K sets of color separation measurement data x, y, z for each wavelength are averaged for each data, and the reflected light amount data x, y, z for each wavelength of the measurement sample is stored in the RAM. And is returned to the main routine.

When the measurement is finished and the process returns to the main routine,
Color separation reflected light quantity data x, y, z for each wavelength of the measurement sample
Based on the color separation reflectance data RDx, RDy, RD
z is calculated.

The color separation reflectance data RDx, RDy,
Since RDz is obtained by removing the influence of ambient light,
The data is equivalent to the data obtained by blocking the ambient light using a dark box as in the past, and is accurate data. The same applies to monochromatic reflectance data in which spectral characteristics do not matter.

Accurate color separation reflectance data RDx, RD
When y and RDz are obtained, they are
Each value of is specified in JIS-Z8701, 8729, respectively.
Calculate according to the procedure specified as X, Y, Z
Is executed, and the chromaticity coordinate x of the XYZ color system,
y or UCS chromaticity coordinate, or L^* a^* b
^* Lightness index L of color system^* And chromaticness index a^* ，
b^* Is displayed, and the result is displayed on the display unit 42.
Alternatively, the output such as printed by a printer not shown
Power is done.

In the embodiment shown in FIG. 3, the detection head constituting the sample measuring means and the detection head constituting the disturbance measuring means are shared by one detection head 50. The detection head 50 itself has the same configuration as the detection head 20 in the above-described first embodiment, and the description "2" is replaced with "5" and the description thereof is omitted. Irradiation light from the incandescent lamp 11 of the light source device 10 similar to that of the first embodiment and ambient light such as natural light or fluorescent light are set on the measurement sample set directly below the detection head 50 as follows. It is configured to be selectively irradiated.

That is, of the two light beams divided by the beam splitter 15 of the light source device 10, the shutter 19 is provided on the front side (right side in the drawing) of the horizontal light beam in the optical axis direction.
Are arranged. The shutter 19 is provided so as to be translated in a direction orthogonal to the horizontal light flux, and the shutter 19 is translated in the up-and-down direction in the drawing, so that the shutter 19 is moved from the incandescent lamp 11 to the incident end 18a of the optical cable 18. The horizontal light flux that reaches is blocked or opened.

Then, as shown in the figure, when the shutter 19 projects into the horizontal light flux and blocks the light flux, the light irradiation from the light projecting section 51 of the detection head 50 is stopped, and the measurement sample 1 is irradiated with natural light. Alternatively, only ambient light such as fluorescent light is emitted. The disturbance diffused light reflected by the measurement sample 1 is received by the light receiving section 52 of the detection head 50.

On the other hand, when the shutter 19 is removed from the horizontal luminous flux, the light of the incandescent lamp 11 is emitted from the light projecting portion 51 of the photodetection head 50, and the disturbance diffused light reflected by the measurement sample 1 is It is received by the light receiving section 52 of the detection head 50. The reflected light from the measurement sample 1 includes the measurement sample 1
Ambient light, that is, natural light or light from a fluorescent lamp or the like is mixed in at the place where is set.

The main body device 40 has the same structure as that of the first embodiment, and has the same calculation function as the color separation reflected light amount data x, y, z for each wavelength of the measurement sample 1. The resolved reflectance data RDx, RDy, RDz are calculated. This color separation reflectance data RDx, RDy, R
Dz is obtained by removing the influence of ambient light, and is accurate data equivalent to the data obtained by blocking ambient light using a dark box as in the related art.

According to the second embodiment as described above, a single detecting head is sufficient, and a simple device can be constructed.

[0047]

As described above, the present invention detects the reflected light amount data of the measurement sample and the reflected light amount data of only ambient light by the detection head arranged in a non-contact state with the measurement sample, Color separation reflected light amount data of the above measurement sample,
Since the reflectance is calculated by correcting the color separation reflected light quantity data of the ambient light, accurate data equivalent to the data obtained by blocking the ambient light using a dark box as in the past can be obtained without contact. The colorimetric measurement can be easily obtained, and therefore highly reliable measurement data can be easily obtained even in an environment in which the blocking of ambient light is insufficient.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory view showing a main part of a colorimeter according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the entire color measurement by the colorimeter shown in FIG. 1, where (A) is a main routine and (B) is a measurement subroutine.

FIG. 3 is a schematic configuration explanatory view showing a main part of a colorimeter according to another embodiment of the present invention.

[Explanation of symbols]

 1 Measurement Sample 3 Standard White Plate 10 Light Source Device 19 Shutters 20, 30, 50 Detection Head 40 Main Unit

Claims (2)

[Claims] 1. A light source device that emits measurement light to a measurement sample, and a detection head that receives reflected light from the measurement sample,
In a colorimeter including a main body device that receives a measurement signal output from the detection head and executes a predetermined calculation to calculate a colorimetric value of the measurement sample, the detection head is isolated from the measurement sample for a predetermined time. The measurement head is provided in a non-contact state, and the detection head is provided with a sample measurement unit that receives reflected light from the measurement sample together with the ambient light and a disturbance measurement unit that receives only the ambient light. The apparatus is provided with an arithmetic unit that corrects the measurement signal output from the sample measuring means of the detection head with the measurement signal output from the disturbance measuring means to calculate a colorimetric value excluding the influence of disturbance light. A colorimeter characterized by being used. 2. A colorimeter adapted to receive the reflected light of the measurement light applied to the measurement sample by a detection head and calculate the colorimetric value of the measurement sample based on the measurement signal output from the detection head. In the colorimetric method, the detection head is separated from the measurement sample by a predetermined distance and placed in a non-contact state, and the reflected light from the measurement sample mixed with the disturbance light and the light of the disturbance light are The detection signals are received separately by the detection heads, and the measurement signal output from the detection head when the reflected light from the measurement sample mixed with the disturbance light is received is output from the detection head when only the disturbance light is received. A colorimetric method for a colorimeter, characterized in that the colorimetric value is calculated by correcting the output measurement signal to eliminate the influence of ambient light.