JP2000193591A - Quantity-of-light measuring apparatus and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring apparatus good in cost performance, capable of stably measuring the reflected light from an object to be measured not uniform in the shape of its reflecting surface or an uneven granular object to be inspected with a simple constitution. SOLUTION: The quantity-of-light measuring apparatus has a plurality of LEDs 2a-2f illuminating the measuring surface of an object to be measured at a predetermined angle, a light detecting element 4 for detecting light reflected in the direction vertical to the measuring surface and a control part 6 for controlling the current flowing to the LEDs 2a-2f to set the quantity level of the reflected light from the measuring surface to a proper level and measuring the quantity of the reflected light set to the proper level a plurality of times to calculate the average value of the light detection values of the light detection element 4 taken in at every measurment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light quantity measuring device and a light quantity measuring method for measuring reflected light or transmitted light of a measuring object having a non-uniform measuring surface or an irregular granular measuring object. .

[0002]

2. Description of the Related Art As a method for measuring reflected light or transmitted light from an object, Japanese Industrial Standard JIS Z 8722 (standard for measuring the color of reflected and transmitted objects) uses a white lamp as a light source.
Is generally used. As an example, FIG. 5 shows an apparatus for irradiating an object with white light emitted from a white lamp and measuring its reflectance and transmittance. This measuring device is disclosed in Japanese Patent Application Laid-Open No. 1-217241, and the relationship between the angle of the illumination light with respect to the measurement surface and the angle of the reflected light or transmitted light to be received is based on Japanese Industrial Standard JIS Z 87.
The following configuration has the relationship specified in 22.

[0003] Mirrors 103a and 103b are arranged symmetrically between a light source 101 and a measurement object 102, and radiated light from the light source 101 reflected by the mirrors 103a and 103b is applied to the surface of the measurement object 102, respectively. On the other hand, irradiation is performed at an incident angle of about 45 ° from directions opposite to each other.

Light receiving elements 105 and 107 are provided on the front side and the back side of the measurement object 102, respectively. The light receiving element 105 receives light reflected in a direction perpendicular to the surface of the measurement object 102 via the lens 104. The light receiving element 107 receives light transmitted through the lens 106 in a direction perpendicular to the surface of the measurement target 102 via the lens 106. The outputs of these light receiving elements 105 and 107 are both input to a light amount detection circuit 108, and are converted into signals corresponding to the reflectance and transmittance of the measurement object 102 by the light amount detection circuit 108. The output of the light quantity detection circuit 108 is
9, the display of the reflectance and the transmittance of the measurement object 102 is possible.

[0005] In the above-described measuring device, the error of the measured value due to the change over time or the temperature of the light emitting portion is determined by the reflectance (or transmittance).
By performing calibration using a known standard piece, stable measurement can be performed.

By the way, the measuring apparatus having the above-mentioned configuration can obtain a stable measured value for a measuring object having a fixed measuring surface, but the measuring surface has a non-uniform or irregular shape. When a granular object is used as the object to be measured, the amount of reflected light differs depending on the shape of the measurement surface or the state of the granule, and as a result, the measured value varies. In order to reduce the variation range of this measurement value,
Conventionally, a method has been adopted in which measurement is performed a plurality of times and an average thereof is taken.

In addition to the above-described method for reducing the variation range of measured values, light emitted from a white lamp is guided using a plurality of optical fibers, and light having strong directivity that has passed through each optical fiber is used. Japanese Patent Laid-Open Publication No.
It is disclosed in Japanese Patent No. 24411. According to this method, the object to be measured is irradiated with light having strong directivity from multiple directions,
Fluctuations in the amount of reflected light due to the shape of the reflecting surface or the state of the granules are smaller than in the case of irradiation from a certain direction.

[0008]

However, the above-mentioned conventional measuring apparatus and measuring method have the following problems.

[0009] The white lamp used for the light source has a finite life, and it is necessary to replace the lamp when the life expires. This lamp replacement is disadvantageous not only in terms of cost but also in terms of maintenance since it is necessary to adjust the optical system every time the lamp is replaced. in this way,
Conventional devices and methods using a white lamp as a light source have been poor in cost performance.

In a method of performing measurement a plurality of times and averaging the results, and a method of irradiating a measurement object from a plurality of directions with strong directivity using a plurality of optical fibers, a variation range of measured values is limited. Although it can be reduced to some extent, the measured value still varies depending on the surface shape and the sample (granular) shape. Therefore, there has been a strong demand for the development of a technology capable of further reducing the range of variation in measured values.

An object of the present invention is to solve the above-mentioned problems and stably measure reflected light or transmitted light of a measurement object having a nonuniform measurement surface or an irregular granular measurement object with a simple configuration. It is an object of the present invention to provide a light quantity measuring device and a light quantity measuring method which can be performed with good cost performance.

A further object of the present invention is to provide a light quantity measuring device and a light quantity measuring method capable of further reducing the variation range of measured values.

[0013]

In order to achieve the above object, a reflected light amount measuring apparatus according to the present invention comprises a light emitting means comprising at least one light emitting diode for illuminating a measurement surface of a measurement object at a predetermined angle. A light receiving unit that receives light reflected or transmitted in a direction perpendicular to the measurement surface, and controls a current flowing through the light emitting diode to adjust the light amount level from the measurement surface to an appropriate level.
Perform the measurement of the light amount several times with the appropriate level,
Control means for calculating an average value (first average value) of the light receiving values of the light receiving means taken in a plurality of times.

In the above case, the light emitting means includes a plurality of light emitting diodes for illuminating the measurement surface of the measurement object from different directions, and the control means sequentially turns on and / or combines the plurality of light emitting diodes. When the light is turned on, the light amount level from the measurement surface may be set to an appropriate level at which the light receiving unit is not saturated. In this case, a standard test piece having a known reflectance or transmittance is provided, and the control means illuminates the standard test piece at the predetermined angle by sequentially lighting and / or combining the plurality of light emitting diodes. The light emitting diode may be configured to measure a light quantity from the standard test piece at each lighting, and to calibrate an error caused by a temporal change or a temperature change of the light emitting diode based on the measurement result.

Further, when the control means calculates the first average value, the control means excludes the maximum value and the minimum value of the light receiving values of the light receiving means taken in each measurement to obtain the first average value. May be configured.

Further, the light receiving element is constituted by a plurality of photodiodes, and the control means has means for calculating an average value (first average value) of the light reception values of the plurality of photodiodes for each measurement. It may be configured. In this case, when the control means calculates the second average value,
The second average value may be obtained by excluding a maximum value and a minimum value among the light reception values of the plurality of photodiodes.

Further, the color of the light emitted from the light emitting diode constituting the light emitting means may be similar to the color of the object to be measured.

According to the light quantity measuring method of the present invention, a measuring surface of a measuring object is illuminated at a predetermined angle by at least one light emitting diode, and light reflected vertically or transmitted through the measuring surface is received. A light amount measuring method for measuring a light amount from the measurement surface based on the light reception value, wherein a current amount flowing through the light emitting diode is controlled to set a light amount level from the measurement surface to an appropriate level; In this state, the measurement of the amount of light from the measurement surface is performed a plurality of times, and the average value (first average value) of the received light values taken in a plurality of times is obtained.

Further, according to the light quantity measuring method of the present invention, a plurality of light emitting diodes illuminate a measurement surface of a measurement object at a predetermined angle from different directions, and light reflected or transmitted in a direction perpendicular to the measurement surface. A light quantity measuring method for receiving light and measuring the light quantity from the measurement surface based on the received light value, wherein the plurality of light emitting diodes are sequentially turned on and / or combined to light the light quantity from the measurement face. The level is set to an appropriate level, and the amount of light from the measurement surface is measured a plurality of times in the state of the appropriate level, and an average value (first average value) of light reception values for each measurement is obtained. . In this case, using a standard test piece having a known reflectance or transmittance, the plurality of light emitting diodes are sequentially lit or combined and lit to illuminate the standard test piece at the predetermined angle, and the standard test in each lighting is performed. The method may further include measuring an amount of light from one of the pieces, and calibrating an error caused by a temporal change or a temperature change of the light emitting diode based on the measurement result.

In any of the above cases, when obtaining the first average value, the maximum value and the minimum value among the light reception values for each measurement may be excluded.

The reflected light from the measurement surface is received by using a plurality of photodiodes, and the average value (second average value) of the light reception values of the plurality of photodiodes is obtained.
May be obtained. In this case, when obtaining the second average value, the second average value may be obtained after excluding the maximum value and the minimum value from the light receiving values of each photodiode.

Further, a light emitting diode having a light emission color similar to the color of the object to be measured may be used as the light emitting diode for illuminating the measurement surface.

(Operation) In the present invention as described above, since a light emitting diode (LED) having a semi-permanent lifetime is used as a light source, it is disadvantageous in terms of cost and maintenance as described in the above-mentioned problem. It is almost unnecessary to replace the lamp.

When the object to be measured has a non-uniform shape, or when the object to be measured is irregular granules, the amount of light varies greatly depending on the direction of the light illuminating the surface to be measured. However, in the present invention, since the measurement surface of the measurement object is illuminated from different directions by the plurality of light emitting diodes, the fluctuation of the light amount is smaller.

In addition, in the present invention, since the light quantity is measured with the light quantity level from the measurement surface being set to an appropriate level, the light receiving element may be saturated or a sufficient light quantity level may not be obtained. No measurements are taken. Therefore, in the present invention, the average value (first average value) of the received light values obtained by measuring the light amount from the measurement surface a plurality of times.
Is more stable than the conventional method of simply calculating the average value of the received light values obtained by a plurality of measurements.

In the present invention, in the invention in which reflected light or transmitted light from a measurement surface is received by a plurality of photodiodes, reflected light or transmitted light from a certain wide range is received and averaged to obtain an average value (first value). (Average value of 2) can be obtained, and the variation of the average value is smaller than the average value obtained by the conventional device in which one light receiving element receives reflected light or transmitted light. For example, when there is a portion where the reflected light or transmitted light greatly fluctuates on a part of the measurement surface of the measurement object (or when the measurement object is granules and granules having significantly different reflectance or transmittance are mixed therein). In the case of a single light receiving element, a portion where the reflected light or transmitted light greatly fluctuates (or a granule having a significantly different reflectance or transmittance) is greatly affected. On the other hand, when a plurality of light receiving elements are used, reflected light or transmitted light over a relatively wide range is received and averaged.
The influence of a portion where reflected light or transmitted light greatly fluctuates (or granules having significantly different reflectance or transmittance) is reduced.

In the present invention, in which the light emitting diode having a light emission color similar to the color of the object to be measured is used, the ratio of the illumination light absorbed by the object to be measured is reduced.

[0028]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of a light quantity measuring device according to an embodiment of the present invention. This light quantity measuring device includes a control unit 6,
The display unit 7, the operation unit 8, and the optical unit 10 whose positional relationship between the light-emitting unit and the light-receiving unit with respect to the measurement surface is defined by the aforementioned Japanese Industrial Standard JIS Z 8722.

The optical unit 10 is composed of a sample case 1 in which irregular, granular, objects of the same color are accommodated, and a measurement object 12 accommodated in the case via the transparent window 1a of the sample case 1. Two light-emitting means (first and second light-emitting units) for illuminating the formed measurement surface 13 at an incident angle of approximately 45 ° from directions opposite to each other, and light reflected in a direction perpendicular to the measurement surface. Light receiving means for receiving light.

Each of the first and second light emitting portions is constituted by an LED having a semi-permanent light emitting life. In the present embodiment, the first light emitting unit includes a light emitting circuit board 3a on which three LEDs 2a to 2c are mounted, and the second light emitting unit includes
It comprises a light emitting circuit board 3b on which two LEDs 2d to 2f are mounted. These light emitting circuit boards are connected to the control unit 6, and the control unit 6 controls the current supplied to each LED. Here, the LEDs mounted on each light emitting circuit board are pairs of LEDs 2a and 2d, LEDs 2b and 2e, and LEDs 2c and 2f, and are symmetrically arranged with respect to the light receiving axis 14 of the light receiving section. FIG. 2 shows an example of the arrangement of the LEDs 2a to 2c. Note that the number and positional relationship of the LEDs are not particularly limited as long as the measurement surface of the measurement object is constantly irradiated with light.

The light receiving means includes a light receiving circuit board 5 on which one or more light receiving elements 4 such as photodiodes are mounted. The output (light reception value) of the light receiving element 4 of the light receiving circuit board 5 is input to the control unit 6.

The sample case 1 has an openable / closable lid 11 provided with a transparent window 1a as shown in FIG. 3, for example.
It can accommodate a granular measurement object such as rice grains. At the time of measurement, a measurement surface 13 is formed by a measurement target housed in a case near the transparent window 1a.

The control section 6 includes an A / D conversion section for A / D converting the output (analog) of the light receiving element 4 and a statistic for taking in the A / D converted value and performing statistical processing such as averaging of the received light value. A processing unit is provided. In addition, the control unit 6 controls each of the LEDs 2a to
In addition to controlling the current supplied to 2f so as to adjust the amount of light irradiated to the measurement surface to an appropriate level, it also controls the operation mode and the measurement mode, etc., which are set and input by the operation unit 8. The calibration and measurement are performed by executing a prepared program. The measurement mode is a mode for measuring the reflected light of the measurement object. The operation mode includes a calibration mode (usually performed before the start of measurement) in which reflected light from a standard test piece having a known reflectance is measured to calibrate a measurement error due to a temporal change or a temperature change of the light emitting unit. There is a maintenance mode for changing software, a constant table, and the like incorporated in the apparatus.

The display unit 7 displays the measurement result statistically processed by the control unit 6, and further displays the mode selected by the operation unit 8 and its related information.

FIG. 4 is a plan view of the light quantity measuring device. The measurement hole 9 is a portion into which the sample case 1 and the standard test piece are inserted. When calibration is performed, a standard test piece (or a sample case in which the standard test piece is set) is inserted into the measurement hole 9, and when measurement is performed, the sample case 1 containing an object to be measured such as rice grains is inserted into the measurement hole 9. Insert

Next, the operation of the reflected light amount measuring device will be specifically described.

(1) Calibration mode A standard test piece is inserted into the measurement hole 9, and the calibration mode is set and inputted by the operation unit 8. When the calibration mode is set and input on the operation unit 8, the control unit 6 executes a program prepared in advance in accordance with the input and acquires calibration data. The LEDs 2a to 2f are sequentially lit and / or lit in combination by current control, the amount of reflected light from the standard test piece in each lighting is measured, and the reflectance calculated based on the measured light is used as calibration data. In the present embodiment, the LEDs 2a to 2f are all blue. The reflectance refers to the ratio of the amount of light reflected from the unit area to the amount of light applied to the unit area. The sequential lighting and combination lighting performed here are performed in the same manner as the lighting in the measurement mode described later. In the present embodiment, calibration data is acquired in three lighting states. That is, the corresponding LEDs provided symmetrically are paired, and the LEDs are paired first, LED2a and LED2d, LED2b and LED2.
e, the LED 2c and the LED 2f are sequentially turned on, and then the LED (2a, 2b) and the LED (2
d, 2e), LED (2a, 2c) and LED (2d, 2d)
f), the LEDs (2b, 2c) and the LEDs (2e, 2f) are sequentially turned on, and finally, three pairs of LEDs, LED (2
a, 2b, 2c) and the LEDs (2d, 2e, 2f) are turned on simultaneously. The control unit 6 calibrates a measurement error caused by a change in the light emission amount due to a temporal change or a temperature change of each LED in the measurement mode based on the calibration data acquired in this manner.

(2) Measurement Mode The sample case 1 containing the object to be measured is inserted into the measurement hole 9, and the “measurement mode” is set and input by the operation unit 8. When the “measurement mode” is set and input by the operation unit 8, the control unit 6 executes a program prepared in advance according to the input to perform measurement. In this measurement, first, the LEDs 2a to 2f are turned on in the same manner as in the above-described calibration mode, and the amount of light reflected from the measurement surface is set to an appropriate level at which the light receiving element 4 is not saturated in each lighting state. Subsequently, in each lighting state, the measurement of the reflected light is performed a plurality of times, and the output (light reception value) of the light receiving element 4 is captured for each measurement. Then, an average value (first average value) of the light reception values in each lighting state is calculated, and the reflectance of the measurement object is obtained based on the first average value.

The following table shows the first example according to the difference in the number of lit LEDs when the polished rice is used as the object to be measured in the apparatus shown in FIG. Shows the range of variation of the average value. Note that the variation range refers to the maximum value of the difference between the average of the first average values obtained ten times and each first average value.

[0041]

[Table 1]

From the results in the above table, it can be seen that measurement is stabilized by irradiating the measurement surface from different directions using a plurality of LEDs. For this reason, the first average value when three pairs of LEDs with the most stable measurement are turned on is used as the measurement result, and the reflectance of the measurement object is obtained based on this. In some cases, depending on the shape, position, direction, and the like of the inspection target, the number of lighted LEDs may be reduced and the measurement may be stabilized by irradiating the measurement surface from a specific direction. When the irradiation mode of the light that stabilizes the measurement (such as the number of lit LEDs) changes each time the inspection object is changed, the variation range is measured as described above during the measurement,
It is desirable to use the first average value as the measurement result when using the light irradiation mode that minimizes the variation range. These variation ranges are plural times (10 in this embodiment).
Since the maximum value and the minimum value of the received light values are eliminated and the first average value is obtained by using the remaining received light values, the first average value is further reduced, so that the reflection of the measurement object is performed based on the first average value. If the ratio is obtained, the reflectance can be measured more accurately.

Further, when the light receiving element 4 is constituted by one photodiode, if granules having remarkably different reflectivity are mixed in the object to be measured, the measured value increases depending on the position of the granules having different reflectivity. fluctuate. For example, when a sample case in which a plurality of brown rices are mixed in polished rice is accommodated in a sample case and measured with one diode, the light receiving area of the photodiode, that is, the photodiode receives reflected light. If there is brown rice in the area on the measurement surface, the amount of reflected light decreases accordingly, and the received light value fluctuates. Thus, when measuring with one photodiode,
Since the amount of reflected light changes depending on the area ratio between brown rice and white rice in the light receiving region of the photodiode, the received light value varies greatly.

The variation in the light receiving value as described above can be reduced by arranging a plurality of photodiodes as the light receiving element 4. That is, by obtaining the second average value from the light reception values measured using a plurality of photodiodes, the light reception values in a wide range are averaged to a certain extent, and the influence of brown rice can be reduced, and stable Measurement becomes possible. For example, the effect of brown rice when measured using N photodiodes is a factor of 1 / N. Note that the variation range of the second average value is further reduced by eliminating the maximum value and the minimum value among the light receiving values of the plurality of photodiodes for each measurement.

In the present invention, when the second average value is obtained, for example, a second average value is obtained from the light receiving values of a plurality of photodiodes for each measurement, and then a plurality of average values obtained by a plurality of measurements are obtained. By averaging the second average,
It is preferable that the first average value is calculated, and the reflectance of the measurement object is obtained using the first average value.

The following table is based on the difference in the number of photodiodes in the apparatus shown in FIG. 1 when a mixture of brown rice mixed with a plurality of brown rice in a sample case is measured. 9 shows a variation range of the second average value.

[0047]

[Table 2]

From the results in the above table, it can be seen that the measurement is stabilized by providing a plurality of photodiodes.

The measuring apparatus of the present embodiment described above is designed to accommodate a granular object to be measured in a sample case, but is also applicable to an object having a non-uniform reflecting surface. be able to. Again, multiple LEDs
By irradiating the measurement surface from different directions by using, the variation of the received light value can be reduced.
Further, in the case of a measurement object having a non-uniform reflection surface, reflected light may vary over a wide range of the measurement surface.In this case, as described above, the reflected light may be varied using a plurality of photodiodes. By taking the average of 2, stable measurement is possible. Also in this case, the variation range is further reduced by eliminating the maximum value and the minimum value of the light receiving value.

In the measuring apparatus of the present embodiment, if the emission color of the LED is selected according to the color of the object to be measured, that is, the emission color of a color similar to the color of the object to be measured is selected. Thereby, it becomes easy to detect a change in reflected light of the measurement object, and more efficient measurement becomes possible. For example, when measuring reflected light of rice or the like, a blue LED is used, and when measuring reflected light of green beans, a green LED is used.
When measuring the reflected light of red azuki, a red LED is used.

As described above, the apparatus for measuring the reflected light of the object to be measured has been described as one embodiment of the present invention. However, the configuration described here can be applied to the apparatus for measuring the transmitted light of the object to be measured. it can. In this case, light transmitted in a direction perpendicular to the measurement surface of the measurement object is received. For example, by forming the sample case 1 with a transparent case, it is possible to receive transmitted light.

[0052]

As described above, according to the present invention,
Since there is almost no need to replace the lamp, which is disadvantageous in terms of cost and maintenance, a measurement system with good cost performance can be provided.

In the invention in which the measurement surface of the measurement object is illuminated from different directions by the plurality of light emitting diodes, the light quantity from the measurement surface can be stably measured irrespective of the shape and the particle direction of the measurement object.

In the invention in which the light amount is measured with the light amount level from the measurement surface being an appropriate level, the light receiving element may be saturated or the measurement may be performed in a state where a sufficient light amount level cannot be obtained. Because there is no light quantity, the stability of the light quantity measurement can be further increased.

In the invention in which reflected light or transmitted light from a somewhat wide range is received by a plurality of photodiodes and averaged, and the value is used as a measurement result, a portion where the light amount fluctuates greatly (or the reflectance or the transmittance Markedly different granules)
Is less affected, so that more stable light quantity measurement can be performed.

In the invention using a light emitting diode having a light emission color similar to the color of the object to be measured, the ratio of the amount of illumination light absorbed by the object to be measured is reduced. This makes it easier to measure the amount of light.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a light quantity measuring device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of an arrangement of the LEDs shown in FIG.

FIG. 3 is a diagram illustrating an example of a sample case illustrated in FIG. 1;

FIG. 4 is a plan view showing an example of an operation panel surface of the light quantity measuring device of the present invention.

FIG. 5 is a block diagram showing a schematic configuration of a measuring device disclosed in Japanese Patent Application Laid-Open No. 1-217241.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sample case 1a Transparent window 2a-2f Light emitting diode (LED) 3a, 3b Light emitting circuit board 4 Light receiving element 5 Light receiving circuit board 6 Control part 7 Display part 8 Operation part 11 Lid 12 Measurement object 13 Measurement surface 14 Light receiving axis

Claims (14)

[Claims] 1. A light emitting means comprising at least one light emitting diode for illuminating a measurement surface of a measurement object at a predetermined angle, and receiving light reflected or transmitted in a direction perpendicular to the measurement surface. Light receiving means, and controlling the current flowing through the light emitting diode to adjust the light amount level from the measurement surface to an appropriate level, perform the light amount measurement a plurality of times with the appropriate level, and capture the light amount a plurality of times. A light quantity measuring device comprising: a control means for calculating an average value (first average value) of light reception values of the light receiving means. 2. The light amount measuring device according to claim 1, wherein the light emitting unit includes a plurality of light emitting diodes that illuminate a measurement surface of the measurement target from different directions, and the control unit includes the plurality of light emitting diodes. A light quantity measuring device, characterized in that the light emitting diodes are sequentially turned on and / or turned on in combination so that the light quantity level from the measurement surface is at an appropriate level so that the light receiving means is not saturated. 3. The light quantity measuring device according to claim 2, further comprising a standard test piece having a known reflectance or transmittance, wherein the control unit sequentially lights and / or combines the plurality of light emitting diodes. The standard test piece is illuminated at the predetermined angle, the light quantity from the standard test piece at each lighting is measured, and an error associated with the aging or temperature change of the light emitting diode is calibrated based on the measurement result. A light quantity measuring device comprising means. 4. The light quantity measuring device according to claim 1, wherein the control means determines a maximum value and a minimum value among light reception values of the light reception means taken in each measurement when obtaining the first average value. A light amount measuring device characterized in that a first average value is obtained by excluding the light amount. 5. The light quantity measuring device according to claim 1, wherein the light receiving element is constituted by a plurality of photodiodes, and wherein the control means controls an average value of light receiving values of the plurality of photodiodes for each measurement ( A first average value). 6. The light amount measuring device according to claim 5, wherein the control unit excludes a maximum value and a minimum value among light reception values of the plurality of photodiodes when calculating the second average value. 2. A light quantity measuring device for obtaining an average value of 2. 7. The light amount measuring device according to claim 1, wherein a light emitting color of a light emitting diode constituting the light emitting means is a color similar to a color of the object to be measured. 8. A measurement surface of an object to be measured is illuminated at a predetermined angle by at least one light emitting diode, and light reflected or transmitted in a direction perpendicular to the measurement surface is received, and based on the received light value. A light amount measuring method for measuring a light amount from the measurement surface, by controlling a current flowing through the light emitting diode to set an appropriate light amount level from the measurement surface, and setting the measurement surface in the state of the appropriate level. A light amount measuring method characterized in that the light amount is measured a plurality of times, and an average value (first average value) of the received light values taken in a plurality of times is obtained. 9. A plurality of light emitting diodes illuminate a measurement surface of a measurement object at a predetermined angle from different directions, receive light reflected or transmitted in a direction perpendicular to the measurement surface, and receive the received light value. A light amount measuring method for measuring a light amount from the measurement surface based on the light emitting device, wherein the plurality of light emitting diodes are sequentially lit and / or lit in combination to set a light amount level from the measurement surface to an appropriate level. A light quantity measuring method, comprising: measuring the light quantity from the measurement surface a plurality of times at an appropriate level, and obtaining an average value (first average value) of light reception values for each measurement. 10. The light amount measuring method according to claim 9, wherein a plurality of light emitting diodes are sequentially lit or combined and lit using a standard test piece having a known reflectance or transmittance. Illuminate at an angle, measure the amount of light from the standard test piece at each lighting,
A light amount measuring method, further comprising calibrating an error caused by a change over time or a change in temperature of the light emitting diode based on the measurement result. 11. The light amount measuring method according to claim 8, wherein when the first average value is obtained, a maximum value and a minimum value are excluded from light reception values for each measurement. Light intensity measurement method. 12. The light amount measuring method according to claim 8, wherein the reflected light from the measurement surface is received by using a plurality of photodiodes, and an average of light reception values of the plurality of photodiodes is received. A light amount measuring method, further comprising obtaining a value (a second average value). 13. The light amount measuring method according to claim 12, wherein the second average value is obtained by excluding a maximum value and a minimum value among light receiving values of each photodiode when obtaining the second average value. A light quantity measuring method characterized by being obtained. 14. The light quantity measuring method according to claim 8, wherein a light emitting diode having a light emission color similar to the color of the object to be measured is used as the light emitting diode for illuminating the measurement surface. Light intensity measurement method.