JPH02221824A - Instrument for measuring characteristic of surface color - Google Patents

Abstract

PURPOSE:To measure the total variation of the color of a traveling belt-like body by forming a scanning light spot on the belt-like body by the use of a light deflection device and detecting the light spot all over the scanning area by an optical fiber through a cylindrical lens. CONSTITUTION:The scanning light spot is formed on the belt-like body 1 by the use of the light deflection device A and detected all over the scanning area by the scanning light spot by the optical fibers 7 and 7' through the cylindrical lens 6. Then, the light is diffused and reflected by an integrating sphere 8 so as to perform spectrum by a diffraction grating 10 and the spectrum is resolved by a photodetector 11 classified by intension. Furthermore, color information is arithmetically operated from the intensity of the spectrum in a colorimetric part C and outputted with scanning light position information to an output device 15. Thus, the characteristic of the surface color of the belt-like body 1 consecutively traveling is accurately measured all over the surface.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a measuring device for measuring surface color characteristics, and particularly for measuring surface color characteristics of continuously manufactured sheet steel plates and non-ferrous metals. The present invention relates to a device suitable for.

<Prior art> Color control of surface-treated strips such as colored steel sheets is important, especially recently.
Painted steel sheets and colored stainless steel sheets used for architectural exterior walls are used as large panel materials, so overall color changes (color unevenness) are important. For this reason,
There is a growing demand for measuring overall color unevenness online and feeding that information back into the manufacturing process.

By the way, conventional means for measuring the surface color of an object include spectrophotometers (for example, Minolta Camera - see catalog) and color testers (for example, Suga Test Machine O).
(Refer to the Catalog of Cubic Denki), etc., and as a means for online color measurement of moving objects, the product name is, for example, Color Identification Device (Refer to the Catalog of Cubic Denki ■). ing.

<Problem to be solved by the invention> However, none of the conventional commercially available products mentioned above can measure overall color changes (color unevenness), and the development of a new device is required. .

As one method to satisfy such requirements, a device for coloring the surface of a moving object as disclosed in, for example, Japanese Unexamined Patent Publication No. 60-14132 has been proposed. A color measurement device 1 capable of measurement is attached to a width direction scanning head 2, and a strip-shaped measurement object 3 is run in the direction of arrow F, and the color measurement device 1 is moved in a direction perpendicular to the running direction, that is, the width of the measurement object 3 The measurement is performed by scanning in the direction and drawing a measurement line locus T.

However, it is difficult to scan at high speed with this device, and since the embellishing device itself has precise optical alignment, it lacks durability against vibrations caused by mechanical scanning. There are several problems that make it extremely difficult to implement.

The present invention has been made in view of such demands, and includes:
An object of the present invention is to provide a surface color characteristic measuring device that can measure the surface color of a continuously running strip over the entire surface and feed back the color variation to the manufacturing process.

Means for Solving the Problems> The present invention provides a light deflection device that irradiates an incident light beam from a light source onto a traveling strip of measurement object to form a scanning light spot, and a light deflection device that forms a scanning light spot over a scanning area by the scanning light spot. a cylindrical lens that extends and has a focal line along the scanning track of the scanning light spot on the strip; an optical fiber located behind the cylindrical lens to receive reflected light from the strip; An integrating sphere that diffusely reflects the reflected light guided by and focuses it on one point, a diffraction grating that separates the light from this integrating sphere, and a spectral intensity of this diffraction grating that is separated into each spectrum and received. The above objective is achieved by comprising a photodetector and an output device that calculates color information from the intensity of the spectrum resolved and received by the photodetector and outputs it together with scanning light position information. It is something to do.

Further, the scanning light to the band-shaped body has an incident angle of 45° with respect to the band-shaped body, and the light reception by the photodetector detects only the diffuse reflected light in the direction perpendicular to the band-shaped body. be able to.

Furthermore, the scanning light to the strip-shaped body is 60° with respect to the strip-shaped body.
It is also possible to have an incident angle of , and the photodetector can detect only specularly reflected light.

<Operation> According to the present invention, a scanning light spot is formed on a strip using an optical deflection device, and the scanning light spot is detected over the entire scanning area of the scanning light spot by an optical fiber via a cylindrical lens. Then, the light is reflected by an integrating sphere into a magnifying glass 11, then separated by a diffraction grating, the resulting spectrum is separated by intensity in a photodetector, and color information is calculated from the intensity of the spectrum in an embellishing section. Since the information is output to the output device along with the scanning light position information, the surface color characteristics of the continuously running strip can be accurately measured over the entire surface.

In addition, the incident angle of the scanning light is set to 45° with respect to the strip, and its vertical expansion n (by detecting only the reflected light,
It is possible to perform measurements that comply with the 0-45@ method specified in the JIS standard.

Furthermore, the incident angle of the scanning light is set to 60" with respect to the strip,
By detecting only the specularly reflected light, the gloss characteristics can be measured in accordance with the JIS standard.

<Examples> Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram schematically showing an embodiment of the present invention, and FIG. 2 is a side view showing the arrangement of cylindrical lenses.

As shown in the figure, the surface characteristic measuring device according to the present invention includes a light source 2. Collimator 3. Optical scanner 41 Cylindrical mouth mirror 5
a reflected light receiving section B consisting of a cylindrical lens 6.6' and an optical fiber bundle 7.7', an integrating sphere 8, a collimator 9° diffraction grating 10. Photodetector 11. The embellishing section C1 includes an analog processing circuit 12, a digital processing circuit 13, a position information processing circuit 14, and an output device 15.

Here, the functions of these component devices will be explained in more detail.

First, in the light deflection device WA, the light source 2 is for irradiating light onto the surface of the moving strip 1 that is the object of measurement. It is preferable to use a white light source such as a tungsten lamp or a xenon lamp.

The collimator 3 includes a lens 31. It is composed of a slit 32 and a lens 33, and has the function of converting the light from the light source 2 into a beam.

The optical scanner 4 has an ability of 81 to scan the parallel light obtained by the collimator 3, and a suitable type thereof is, for example, a galvano scanner that performs reciprocating motion, but a polyhedral rotating mirror may also be used. , the scanning speed of the optical scanner 4 is determined in relation to the traveling speed of the strip l.

The cylindrical concave mirror 5 has the ability to irradiate and reflect the light scanned by the optical scanner 4 onto the surface of the strip l to be measured, but the incident angle θ is the same angle with respect to each scanning line. It is fine as long as it works.

Next, in the reflected light receiving section B, the cylindrical lens 6.6'
has the function of condensing the reflected light reflected on the surface of the strip l, and the focal length of the reflected light is set so that the focal line distance is equal to the scanning track S of the scanning light spot formed on the surface of the strip l. will be placed in That is, as shown in FIG. 2 in detail, the cylindrical lens 6 is set at an angle θ with respect to the vertical line V of the scanning track S so that the cylindrical lens 6 receives light in the specular reflection direction with respect to the incident angle θ of the incident light. On the other hand, the cylindrical lens 6' is arranged perpendicular to the scanning track S so as to receive the diffusely reflected light. As a result, the reflected light from the scanning track S on the surface of the strip 1 becomes light having a width parallel to the running direction of the strip 1. This is effective in reducing the light receiving surface of the optical fiber bundle 7°7'.

The optical fiber bundle 7.7' has the function of receiving reflected light from the strip 1 via a cylindrical lens 6.6' and guiding the light to connecting surfaces Ha and 8b of an integrating sphere 8, which will be described later. ,
Compared to the spread of the reflected light in the width direction of the strip l, since the light receiving surfaces thereof are extended in the width direction, the spread of the reflected light does not become excessive.

Further, the integrating sphere 8 has the function of diffusing and reflecting the reflected light from the optical fiber bundle 7.7' on its inner surface, and condensing the reflected light to one point on the lens 9I of the collimator 9 provided on the inner surface.

Now, to explain the function of the integrating sphere 8 in a little more detail, the reflected light collected by the optical fiber bundles 7 and 7' is diffused and emitted from the end of the optical fiber east 7 and 7'.

Also, optical fiber bundle 7. ．． The light emitted from 7' is not uniformly distributed light (it becomes a spot light of the output fiber).
0, the incident light (diffracted light) to the photodetector 11, such as a photodiode array (described later), is not uniform between measurement positions and depends on which fiber it comes out from. It becomes essential to spatially homogenize the light from the fiber before it enters the diffraction grating 10.

Therefore, in this integrating sphere 8, the light emitted from the fiber undergoes multiple reflections on the inner wall, and the light becomes spatially uniform at the exit window regardless of which part of the fiber the light is emitted from. The incident light on the diffraction grating 10 does not vary depending on the measurement position, and the reflection characteristics of the reflective surface are transmitted as they are.

Furthermore, in the embellishing section C, the collimator 9 is equipped with a lens 91.
．． Slit 92. It is composed of a lens 93 and an integrating sphere 8.
It has a function of forming a beam from the light condensed in the diffraction grating IO and guiding it to the diffraction grating IO.

The diffraction grating IO has a function of converting the light incident from the integrating sphere 8 into a spectrum.

The photodetector 11 has a function of decomposing the spectrum from the diffraction grating IO into intensities of appropriate pitches and receiving the light.

The analog processing circuit 12 and the digital processing circuit 13 are
The intensity of the spectrum decomposed and received by the photodetector 11 is calculated, processed into colorimetric data such as a, b, etc., and outputted to the output device 15 4! ! has the ability to

These analog processing circuit 12 and digital processing circuit 1
The contents of each arithmetic processing in 3 are described in the above-mentioned Japanese Patent Application Laid-open No. 60-1.
It is the same as that disclosed in No. 4132.

That is, the analog processing circuit 12 is a circuit that performs analog integration processing on the electric signal for each wavelength obtained by the photodetector 11 in a constant integration time that is correlated with the signal processing time of the subsequent stage, and the digital processing circuit 13 is , an analog-digital IR function that converts an analog electrical signal from the analog processing circuit 12 into a digital signal, and an arithmetic processing function that calculates a color difference from the digital signal.

At this time, the color difference calculation is performed according to, for example, JIS 8730-19.
The formula of the Lab color system defined in the color difference display method of No. 70 can be applied. The color difference ΔE from the standard white plate at each point can be determined from the a and b values of this color system, and by showing this distribution, it is possible to measure the color unevenness or control the coloring device. Become.

The position information processing circuit 14 has a function of outputting scanning light position information in the width direction of the strip l to the output device 15. FIG. 3 shows an example in which a polyhedral rotating mirror is used as the optical scanner 4, and the light from the collimator 3 is scanned by the polyhedral mirror 41 rotated at rotation 842 and scanned in the width direction of the strip l. Although it is irradiated as light, the position in the width direction at that time is detected by a rotational position detector 42 coupled to the shaft of a rotating machine 42 and input manually to the position information processing circuit 14.

Output equipment! Reference numeral 15 includes a unit that associates the color measurement data from the digital processing circuit 13 with the scanning light position information from the position information processing circuit 14 and outputs the correlated data to, for example, a manufacturing line (not shown).

With such a device configuration, it is possible to measure the color characteristics of the entire surface in the width direction in synchronization with the speed of the traveling strip l.

In the above embodiment, the surface color information is calculated by detecting both the specular reflection light and the diffuse reflection light of the reflected light from the strip 1. However, in the JIS standard, for example, it is called the 0-45@ method. There is a color embellishment method, in which it is specified that only diffusely reflected light is received at an irradiation angle of 45° with respect to the object to be measured. Therefore, in order to adapt the present invention to this regulation, as shown in FIG. This can be realized by receiving only the diffusely reflected light by the lens 6' and the optical fiber 7'.

In addition, for measurement objects that are very specular and have strong reflective components,
The characteristic of gloss is also specified in the JIS ffl rating, and in this case, the irradiation angle is specified to be 60@ to receive only specularly reflected light. Therefore, in order to make the present invention conform to this regulation, as shown in FIG. This can be realized by using only the cylindrical lens 6 set at an angle of 60 degrees with respect to the body 1 and the optical fiber 7.

<Effects of the Invention> As explained above, according to the present invention, it is possible to measure the overall color variation of a moving band-shaped object such as a painted steel plate or a colored stainless steel plate whose color characteristics are important.

Therefore, it is possible to feed back the color variation information to the manufacturing process, so in the case of painted steel plates, for example, uniform coating is possible by adjusting the alignment of the coating roll based on the color variation information, and In the case of colored stainless steel plates, it is possible to obtain more uniform coloring by adjusting the electrode current of the electrolytic cell in a similar manner.

This can greatly contribute to improving product quality.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram schematically showing an embodiment of the present invention, and FIG.
The figure is a side view showing the arrangement of the cylindrical lens according to the present invention, FIG. 3 is a configuration diagram schematically showing an example of the optical scanner according to the present invention, and FIGS. 4 and 5 are other embodiments. FIG. 6 is a side view partially illustrating a conventional example, and FIG. 6 is a perspective view schematically illustrating a conventional example. 13...Digital processing circuit. 14...Position information processing circuit. 15... Output device. A... Light deflection device. B...Reflected light receiving section. C... embellishment part. 1... Band-shaped body. 3...Collimator. 5... Cylindrical concave mirror. 7...Optical fiber. 9...Collimator. 11... Photodetector. 2...Light source. 4... Optical scanner. 6...Cylindrical lens. 8... Integrating sphere. 10... Diffraction grating. 12...Analog processing circuit.

Claims (1)

[Scope of Claims] 1. A light deflection device that irradiates an incident light beam from a light source onto a traveling strip-shaped object to be measured to form a scanning light spot; a cylindrical lens having a focal line along the scanning track of a scanning light spot on the body; an optical fiber positioned behind the cylindrical lens to receive reflected light from the strip; and a light guided by the optical fiber. An integrating sphere that diffusely reflects reflected light and focuses it on one point,
A diffraction grating that separates the light from this integrating sphere, a photodetector that separates the spectral intensity of this diffraction grating into each spectrum and receives the light, and color information is obtained from the intensity of the spectrum that is separated and received by this photodetector. A surface color characteristic measuring device comprising: an output device that calculates and outputs the calculated information along with scanning light position information. 2. The scanning light to the strip-shaped body is at an angle of 45 degrees with respect to this strip-shaped body.
2. The surface color characteristic measuring device according to claim 1, wherein the surface color characteristic measuring device has an incident angle of , and a photodetector detects only diffusely reflected light in a direction perpendicular to the strip. 3. The scanning light to the strip-shaped body is 60° with respect to this strip-shaped body.
2. The surface color characteristic measuring device according to claim 1, wherein the surface color characteristic measuring device has an incident angle of , and the photodetector detects only regularly reflected light.