JPH01263526A - Method of calibrating photometric scale in continuous measurement of reflected light and apparatus therefor - Google Patents

Abstract

PURPOSE:To improve the precision in measurement by a method wherein a reflected light from a regular standard white face is sensed, a reflectivity is measured therefrom, this measured reflectivity is compared with a known reflectivity, and a photometric scale is calibrated on the basis of the comparison. CONSTITUTION:A moving stage 4 being positioned at a measuring position, illuminating lights from two projections 6 are applied onto the surface of a substrate 2 to be conveyed. Next, a reflected light from the substance 2 is sensed by a photosensor 7, and this light is led to an arithmetic unit through a photoelectric converter and an A/D converter, a reflectivity etc. are thereby computed, and calculated data are stored in a memory. For calibration of a photometric scale, the moving shape 4 is positioned at a calibrating position, while a moving stage 10 for setting is moved by turning, so that the illuminating lights from the two projectors 6 are applied onto a regular standard white 9. A reflected light from the white face 9 is sensed by the photosensor 7, and this light is led to the arithmetic unit through photoelectric converter and the A/D converter, a reflectivity is thereby computed, the calculated reflectivity is inputted to a comparative operator, the reflectivities of the white face 9 and the substance 2 are compared with each other, and the photometric scale is calibrated on the basis of the comparison.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for calibrating a light intensity scale in continuous measurement of reflected light to determine the optical characteristics of the surface of a transported object.

[Conventional technology]

Traditionally, films, sheets, paper, cloth, etc. that are continuously conveyed
Illumination light is projected onto the surface of an object to be conveyed, such as a plastic plate or painted plate, at a required angle (for example, 45"), and the reflected light is received at the required reception angle to the reflection spot of the object to determine the reflectance. To calibrate the light intensity scale when continuously measuring optical properties such as Receive light and measure reflectance,
A method is used to 100% calibrate the light intensity scale by comparing this measured reflectance with a known reference reflectance given to this white surface.

[Problem to be solved by the invention]

However, the conventional method described above has a problem in that measurement errors occur due to fluctuations in the light source during continuous measurement, dust in the measurement atmosphere, or temperature changes in the measurement atmosphere.

Therefore, in the present invention, the measurement conditions and the calibration conditions are the same,
It is an object of the present invention to provide a method and apparatus for calibrating a light intensity scale in continuous measurement of reflected light, which can improve the accuracy of n1 determination.

[Means to solve the problem]

In order to solve the above-mentioned problems, a first invention projects illumination light onto the surface of an object to be transported at a required angle, receives the reflected light at a required reception angle with respect to the reflection spot of the object, and determines its optical characteristics. When continuously measuring A commonly used standard white surface with a known reflectance is placed at the position where the reflectance is known, and the reflectance is measured by receiving the reflected light from the commonly used standard white surface, and this measured reflectance is compared with the known reflectance. This is a method of calibrating the luminosity scale.

A second aspect of the present invention is to project illumination light onto the surface of an object to be transported at a predetermined angle, and to continuously measure the optical characteristics of the reflected light by receiving the reflected light at a required acceptance angle with respect to the reflected spot of the object to be transported. A commonly used standard white surface with a known reflectance is placed on the same plane as the surface of the transported object on the side of the transported object. Move parallel to the surface of the conveyed object to position the light receiving spot above the commonly used standard white surface, and measure the reflectance by receiving the reflected light from the commonly used standard white surface. This method calibrates the luminosity scale by comparing the reflectance of

A third aspect of the invention is to project illumination light onto the surface of an object to be conveyed at a required angle, receive the reflected light at a required acceptance angle with respect to a reflected spot of the object, and continuously measure the optical characteristics of the illumination light. A commonly used standard white surface with a known reflectance is placed on the side of the intermediate position between the light projecting spot, the reflected light receiving spot, and the reflected spot of the conveyed object, with the distance between the above intermediate position and the reflective spot. Installed perpendicularly to the surface of the object to be transported or at a required angle, and at the intermediate position 45" relative to the surface of the object to be transported.
Alternatively, move a mirror or prism tilted at the required angle at required intervals and place it facing a commonly used standard white surface, and measure the reflectance by receiving the reflected light from the commonly used standard white surface. This method calibrates the luminous intensity scale by comparing the reflectance with a known reflectance.

A fourth invention is an apparatus used for carrying out the method of the first invention, which includes a moving table that is provided to be able to move forward and backward almost perpendicularly to the surface of the object to be transported, and a device that is attached to the moving table and that is attached to the surface of the object to be transported. a projector that emits illumination light at a required angle;
A light receiver that receives reflected light from the surface of the transported object, and a mounting moving table that moves by placing a commonly used standard white surface with a known reflectance on the intersection of the optical axes of the light emitter and light receiver in the retracted position. and a comparator for calibrating the luminous intensity scale by comparing the reflectance of a commonly used standard white surface received and measured by the light receiver with a known reflectance.

A fifth invention is an apparatus used for carrying out the method of the second invention, which includes a commonly used standard white surface with a known reflectance installed on the side of the object to be transported on the same plane as the surface thereof; A movable platform that is movable from above the surface to above the object to be transported in parallel with the surface thereof; a light projector that is attached to the moving platform and projects illumination light onto the surface of the object to be transported; and the object to be transported. A light receiver is installed on the moving table and positioned above the reflective spot on the surface to receive the reflected light from the surface of the transported object. It consists of a comparison calculator that compares and calculates the reflectance and calibrates the luminous intensity scale.

A sixth invention is an apparatus used for carrying out the method of the third invention, which includes a mounting base installed above an object to be transported, and a device attached to the mounting base to project illumination light at a required angle onto the surface of the transported object. A light projector that emits light, a light receiver that is mounted on a mounting base and located above the reflective spot on the surface of the transported object and receives the reflected light from the surface of the transported object, and a position intermediate between the light projector, the receiver, and the reflective spot. A commonly used standard white surface with a known reflectance and placed at a distance between this intermediate position and the reflection spot and perpendicular to the surface of the transported object or at a required angle, and a mirror or prism that is tilted by 45'' or a required angle, is moved to the intermediate position every required time, and is placed opposite the commonly used standard white surface; and the reflection of the commonly used standard white surface that is received by a light receiver and measured. It consists of a comparator that calibrates the luminous intensity scale by comparing the reflectance with the known reflectance.

[For production]

According to each of the above means, the conditions for measuring the reflected light from the surface of the transported object are the same as the conditions for calibrating the luminous intensity scale by measuring the reflected light from the commonly used standard white surface.

The movement of the commonly used standard white surface in the apparatus of the fourth invention is a rotational movement about an axis perpendicular to the surface of the object to be transported, a linear reciprocating movement parallel to the surface of the object to be transported, or other movements.

Further, the movement of the movable table in the apparatus of the fifth invention is a linear reciprocating movement parallel to the surface of the object to be transported and perpendicular to the transport direction, a turning movement about an axis perpendicular to the surface of the object to be transported, or other movement.

Furthermore, when the calibration time interval becomes large and the light source fluctuates rapidly, it is desirable to add a method and arrangement for monitoring the light source fluctuations using another commonly used standard white surface.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are a front view and a side view of the luminous intensity scale calibration device of the first embodiment.

In the figure, reference numeral 1 denotes a substrate, which is provided above the transported object 2 by a frame (not shown). Two guide rods 3 are installed on the substrate 1 perpendicularly to the surface of the transported object 2.
A movable table 4 slidably fitted to the guide rod 3 is provided so as to be movable forward and backward relative to the surface of the conveyed object 2 by means of an air cylinder 5. Two projectors 6 that project illumination light from a light source (not shown) onto the surface of the transported object at an angle of 45 degrees are attached to the movable table 4, and the intersection of the optical axes of both projectors 6 is at tJS1. As shown in FIGS. 2 and 2, the moving table 4 is provided so as to coincide with the surface of the transported object 2 at an advanced position (measurement position) close to the transported object 2. As shown in FIG. Further, a light receiver 7 for receiving reflected light from the surface of the transported object is attached to the movable table 4 so as to be positioned on a perpendicular line to the reflection spot 8 on the surface of the transported object.

On the other hand, at the lower end of the one guide rod 3, as shown in FIG. On the intersection, a mounting table 10 on which a commonly used standard white surface 9 for calibration with a known reflectance is mounted and moves is attached so as to be pivotable about one of the guide rods 3 . The mounting and moving table 10 has a converting member 11 which has a bendable middle part, one end of which is swingably attached to the mounting and moving table 10, and the other end of which is swingably attached to the moving table 4. , the linear movement of the moving table 4 is converted into a turning movement of the mounting moving table 10, and as the moving table 4 retreats (increases in the figure), it is provided so as to be able to turn about 1/4 turn on the intersection of the optical axes. ing.

Continuous measurement of reflected light in the light intensity scale calibration device having the above configuration is carried out by placing the movable table 4 at the measurement position and directing the illumination light from both projectors 6 to the object to be transported, as shown in FIGS. 1 and 2. The reflected light from the conveyed object 2 is received by the light receiver 7, and is guided to a computing unit (none of which is shown) through a photoelectric converter and an A/D converter, where it is reflected. Optical characteristic values such as ratio are calculated and the calculated data is stored in a memory (not shown).

In addition, to calibrate the light intensity scale, as shown in FIG. Light is projected onto a white surface 9, and the reflected light from the commonly used standard white surface 9 is received by a light receiver 7, which is then sent to a photoelectric converter and an A/
The light is guided through a D converter to a calculator to calculate the reflectance, and the calculated reflectance is input to a comparator and compared with the known reflectance of the commonly used standard white surface 9 to calibrate the light intensity scale.

FIG. 4 and FIG. 5 are a front view and a plan view of the luminous intensity scale calibration device of the second embodiment.

In the figure, reference numeral 12 denotes an opposing substrate, which is provided above a frame (not shown) so as to be spaced apart in a direction perpendicular to the conveyance direction of the conveyed object 2. There are two rods 13 on the board 12.
is installed parallel to the surface of the transported object 2 and perpendicular to the transport direction, and the moving table 14, which is slidably fitted to the guide rod 13, is connected to a commonly used standard for calibration by an air cylinder 15, as will be described later. It is provided so as to be able to move forward and backward from above one side of the transported object 2 on which the white surface is placed above the transported object 2. Two projectors IB that project illumination light from a light source (not shown) onto the surface of the transported object at an angle of 45" are attached to the moving table 14. The intersection of the optical axes of both projectors 1B is It is provided so as to coincide with the surface of the conveyed object.

Further, a light receiver 17 for receiving reflected light from the surface of the object to be transported is attached to the moving table 14 so as to be located on a perpendicular line to the reflection spot 18 on the surface of the object to be transported. and,
On one side of the object to be transported 2, a commonly used standard white surface 19 for calibration with a known reflectance is positioned on the same plane as the surface of the object to be transported 2 via a bracket 20 attached to one of the substrates 12. It is installed.

Continuous measurement of reflected light and calibration of the luminous intensity scale in the luminous intensity scale calibration device having the above configuration are carried out by moving the moving table 14 so that the light receiver 17 moves toward the object to be transported as shown in FIGS. 4 and 5.
This is carried out in the same manner as in the first embodiment at the forward position (a-regular position) located above and at the retracted position (calibration position) located above the commonly used standard white surface 19.

FIG. 6 and FIG. 7 are a front view and a side view of the luminous intensity scale calibration device of the third embodiment.

Reference numeral 21 in the figure is a mounting base, and a frame (not shown) is used to hold the objects to be transported.
It is located above the . Two projectors 22 that project illumination light from a light source (not shown) onto the surface of the transported object at an angle of 45" are attached to the mounting base 21. Both projectors 22
The intersection of the optical axes of is arranged to coincide with the surface of the transported object. Further, a light receiver 23 for receiving reflected light from the surface of the object to be transported is attached to the mounting base 21 so as to be located above the reflection spot 24 on the surface of the object to be transported.

A commonly used standard white surface 25 for calibration with a known reflectance is attached to the mounting base 21 via the bracket 2B on the side of the intermediate position between the emitter 22 and the receiver 23 and the reflective spot 24, and and the distance between the reflective spot 24 (
(half distance between emitter and receiver and reflection spot)
and is provided perpendicularly to the surface of the transported object 2.

On the other hand, two guide rods 27 are installed on the mounting base 21 in parallel with the surface of the object 2 to be transported and in the same direction as the transport direction. A movable base 28 slidably fitted to the guide rod 27 is provided so as to be movable upwardly and retractably above the reflection spot 24 by an air cylinder 29.
At 8, a mirror or prism 3o facing the standard white surface 25 and tilted 45'' with respect to the surface of the conveyed object 2 is moved through a bracket 3I to move forward and backward with respect to the intermediate position. installed.

Continuous measurement of reflected light and calibration of the luminous intensity scale in the luminous intensity scale calibration device configured as described above are carried out by moving the movable table 28 to a retracted position (measurement position) and an intermediate forward position (calibration position) in the same manner as in the first and second embodiments.

Therefore, according to the luminous intensity scale calibration apparatus of the first to third embodiments, the measurement conditions of the reflected light and the luminous intensity scale calibration conditions are the same, and fluctuations in the light source, dust in the measurement atmosphere, or temperature changes in the measurement atmosphere are No measurement error occurs regardless of the

FIG. 8 is a schematic diagram of a luminous intensity scale calibration device according to a fourth embodiment.

In the figure, 32 is a light projector that projects illumination light from a light source 33 onto the surface of the transported object 2 at 45@, and 34 is a light receiver located above the reflection spot 35 on the surface of the transported object. The light projector 32 and the light receiver 34 are configured to receive reflected light from the surface of an object, and are provided so as to be able to move back and forth a required distance perpendicularly to the surface of the object 2 to be transported.

36 is a commonly used standard white surface for calibration with a known reflectance, and when the emitter 32 and receiver 34 are moved back from the forward position (measurement position) shown in FIG. 8 to the retracted position (calibration position) shown in FIG. It is then moved so that it is located on the intersection of their optical axes.

Reference numeral 37 is a projector for projecting the illumination light from the light source 33 onto the standard white surface 38 for reference at 45 @; 39 is located on the perpendicular line of the reflection spot 40 of the standard white surface 38; This is a light receiver that receives reflected light from the white surface 38.

Reference numeral 41 denotes a photoelectric converter consisting of an interference filter 41a, a photodiode array 41b, etc., which receives reflected light from the surface of the conveyed object received by the light receiver 34 or from the commonly used standard white surface 3B for calibration, or a reference light received by the light receiver 39. The reflected light from the commonly used standard white surface 38 is photoelectrically converted.

42 is a half mirror 143 is a receiver 34 and a half mirror
One shutter 42 is interposed in the optical path, and 44 is the other shutter interposed in the optical path of the reference light receiver 39 and the half mirror 42.

Continuous measurement of reflected light in the light intensity scale calibration device configured as described above is carried out as shown in FIG. At the same time, one shutter 43 is opened and the other shutter 44 is closed.

The reflected light from the transported object 2 received by the light receiver 34 is photoelectrically converted by the photoelectric converter 41, and then inputted to a computing unit (both not shown) via an A/D converter to calculate reflectance, etc. Optical characteristic values are calculated and the data is stored in memory (not shown).

Then, one shutter 43 is closed and the other shutter 44 is opened. The reflected light from the commonly used standard white surface 38 for reference received by the light receiver 39 is transmitted to the photoelectric converter 4
After being photoelectrically converted by 1, the data is inputted to a computing unit via an A/D converter, the reflectance is computed, and the computed data is stored in a memory.

During the continuous measurement, it is desirable to close both shutters 43 and 44 to calculate the dark current value and correct the optical characteristic value of the object 2 to be transported and the reflectance of the commonly used standard white surface 38 for reference.

On the other hand, in order to calibrate the light intensity scale, as shown in FIG.
And while setting the regularly used standard white surface 36 for calibration,
Open one shutter 43 and open the other shutter 4
Close 4. The reflected light from the commonly used standard white surface 36 for calibration, which is received by the light receiver 34, is transmitted to the photoelectric converter 41.
After being subjected to photoelectric conversion, the data is inputted to an arithmetic unit via an A/D converter, the reflectance is calculated, and the calculated data is stored in a memory.

Then, one shutter 43 is closed and the other shutter 44 is opened. The reflected light from the commonly used standard white surface 38 for reference received by the light receiver 39 is transmitted to the photoelectric converter 4
After being photoelectrically converted by 1, the data is inputted to a computing unit via an A/D converter, the reflectance is computed, and the computed data is stored in a memory.

Then, the measured reflectance of the commonly used standard white surface 36 for calibration, the known reflectance, and the reflectance of the commonly used standard white surface 38 for reference during measurement and calibration are input into a comparison calculator (not shown). calibrate the light intensity scale.

During the above calibration measurement, it is desirable to close both shutters 43, 44, calculate the dark current value, and correct the reflectance of the commonly used standard white surface 36, 88 for calibration and reference, as in the case of continuous measurement.

Therefore, according to the light intensity scale calibration device of the fourth embodiment, when the calibration time interval becomes large and the light source fluctuates sharply, the light source fluctuation can be monitored, and the measurement conditions of reflected light and the light scale can be adjusted. Calibration conditions are even more the same.
Therefore, measurement accuracy can be further improved.

In the light intensity scale calibration device of the first embodiment, the movable table 10 is rotated, but is not limited to this and may be moved back and forth in a straight line.

Furthermore, the movable tables 14 and 28 of the second and third embodiments are not limited to linearly reciprocating movement, but may also be configured to rotate around an axis perpendicular to the surface of the transported object.

Furthermore, the emitter 32 and the receiver 34 of the fourth embodiment and the commonly used standard white surface 36 for calibration are not limited to the case where both are moved.
may be provided on one side of the object to be transported, and only the light projector 32 and light receiver 34 may be moved, or a mirror may be used as in the third embodiment.

Furthermore, in order to prevent dust from adhering to the commonly used standard white surface for calibration in each example, air was blown to keep the commonly used standard white surface clean, thereby improving the -layer side constant accuracy. will improve.

〔Effect of the invention〕

As described above, according to the present invention, the conditions for measuring the reflected light from the surface of the transported object are the same as the conditions for calibrating the luminous intensity scale by measuring the reflected light from a commonly used standard white surface. Regardless of dust in the measurement atmosphere or temperature changes in the measurement atmosphere, measurement errors do not occur, and measurement accuracy can be improved.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show an embodiment of the present invention, and FIGS. 1, 2, and 3 are a front view, a side view, and an operation explanatory diagram of the luminous intensity scale calibration device of the first embodiment, 4 and 5 are a front view and a plan view of a light intensity scale calibration device of the second embodiment, and FIGS. 6 and 7 are a front view and a side view of a light intensity scale calibration device of the third embodiment, FIGS. 8 and 9 are schematic configuration diagrams of a luminous intensity scale calibrating device according to a fourth embodiment and explanatory diagrams of the functions of the main parts thereof. 2... Object to be transported 4... Moving table 6...
Emitter 7...Receiver 8...Reflection spot 9...Commonly used standard white surface lO...Moving table 14...Moving table 16...Emitter
17...Receiver 18...Reflection spot
19... Commonly used standard white surface 21... Mounting base
22... Emitter 23... Light receiver
24...Reflective spot 25...Usual standard white surface Application Person Murakami Color Technology Research Institute Figure 1 Figure 2 Figure 3 82 t
Figure 6 Figure 7 Z':) 24 j (J JI Z Figure 8

Claims (6)

[Claims] (1) When illuminating light is projected onto the surface of the transported object at a required angle, and the reflected light is received at the required acceptance angle with respect to the reflected spot of the transported object to continuously measure its optical characteristics, the illumination light is The light emitting spot and the receiving spot of the reflected light are separated by a required distance above or below the surface of the transported object at each required time, and the reflectance is known at a position separated from the reflected spot of the transported object by this moving distance. Position a standard white surface and measure the reflectance by receiving the reflected light from the commonly used standard white surface.
A method for calibrating a light intensity scale in continuous measurement of reflected light, comprising calibrating the light intensity scale by comparing the measured reflectance with a known reflectance. (2) When illumination light is projected onto the surface of the transported object at a required angle, and the reflected light is received at the required reception angle with respect to the reflected spot of the transported object, and its optical characteristics are continuously measured, A commonly used standard white surface with a known reflectance is placed on the same plane as the surface of the transported object, and the illumination light emitting spot and reflected light receiving spot are set on the side of the transported object. The light receiving spot is positioned above the commonly used standard white surface by moving parallel to the surface of the commonly used standard white surface, and the reflectance is measured by receiving the reflected light from the commonly used standard white surface. A method for calibrating a light intensity scale in continuous measurement of reflected light, the method comprising calibrating the light intensity scale by comparing rates. (3) When illuminating light is projected onto the surface of the transported object at a required angle, and the reflected light is received at the required reception angle with respect to the reflected spot of the transported object to continuously measure its optical characteristics, the illumination light is A commonly used standard white surface with a known reflectance is placed on the side of the intermediate position between the light emitting spot, the receiving spot of the reflected light, and the reflective spot of the conveyed object, with the distance between the above intermediate position and the reflective spot being conveyed. A mirror or prism is installed perpendicularly to the surface of the object or at a required angle, and is tilted at 45 degrees or at a required angle to the surface of the object to be transported at the intermediate position, and is moved every required time to create a commonly used standard white surface. , and measures the reflectance by receiving reflected light from a commonly used standard white surface, and calibrates the light intensity scale by comparing the measured reflectance with a known reflectance. A method for calibrating the light intensity scale in continuous measurements of light. (4) A movable stage that is movable back and forth almost perpendicularly to the surface of the transported object; a light projector that is attached to the mobile stage and projects illumination light at a required angle onto the surface of the transported object; A light receiver is installed on the moving table above the reflective spot on the surface of the transported object and receives the reflected light from the surface of the transported object, and a reflector is placed on the intersection of the optical axes of the emitter and the receiver in the retracted position. a mounting table on which a commonly used standard white surface with a known value is placed and moved; the reflectance of the commonly used standard white surface received and measured by the light receiver; and the known reflectance given to this white surface. A device for calibrating a light intensity scale in continuous measurement of reflected light, comprising: a comparator for calibrating the light intensity scale by comparing and calculating the light intensity scale. (5) A commonly used standard white surface with a known reflectance installed on the side of the object to be transported on the same plane as the surface, and a direction parallel to the surface from above the commonly used standard white surface to above the transported object. A movable base that can move forward and backward, a floodlight that is attached to the movable base and emits illumination light onto the surface of the transported object, and a floodlight that is installed on the movable base and is located above the reflective spot on the surface of the transported object. A light receiver that receives the reflected light from the surface of the transported object, and a comparison calculation that calibrates the light intensity scale by comparing the reflectance of a commonly used standard white surface that is received and measured by the light receiver with the known reflectance. A calibration device for a light intensity scale in continuous measurement of reflected light, characterized by comprising: (6) A mount installed above the object to be transported, a floodlight that is attached to the mount and projects illumination light at a required angle onto the surface of the object to be transported, and a reflection spot above the surface of the object to be transported. A light receiver is attached to the mount and receives the reflected light from the surface of the transported object, and a distance between this intermediate position and the reflection spot is located on the side of the intermediate position between the emitter and receiver and the reflection spot. A commonly used standard white surface with a known reflectance is installed perpendicular to the surface of the transported object or at a required angle, and a standard white surface is tilted at 45° or at a required angle relative to the surface of the transported object and placed at the intermediate position. A light intensity scale is calculated by comparing the reflectance of a mirror or prism that is moved every required time and placed opposite the standard white surface, and the known reflectance of the standard white surface that is received and measured by a light receiver. A calibrating device for a light intensity scale in continuous measurement of reflected light, comprising a comparator for calibrating.