JP2001074639A - Grain size distribution-measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve measuring accuracy and working efficiency by detecting the image pickup state of each image data based on the image data that has been picked up, and at the same time by controlling a driving source based on the detected image pickup state for adjusting the amount of supply of a sample. SOLUTION: In a grain size distribution-measuring device 1, a vibration feeder 2 is driven by power supply from a driving source 3 for conveying a sample S, and the image of the sample S falling from the vibration feeder 2 is picked up by an image pickup device 4. In a controlling device 5, the image of an image pickup device 6 is taken in by an image-take-in device 9, and image data that has been picked up by a computer 10 is processed. The processed result is displayed on an image monitor 11, and at the same time is printed to a printer 12. Then, shading ratio obtained from the image data that has been picked up by the image pickup device 4 is compared with a criterion being set in advance, the amplitude of the vibration feeder 2 is adjusted according to the difference for increasing and decreasing the amount of conveyance, and the amount of conveyance of the sample S being dropped and supplied to an image pickup part is automatically controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particle size distribution measuring apparatus for measuring the particle size distribution of various powder samples in the field of powder industry, and more particularly, to controlling the supply amount of powder samples to an image pickup unit to an appropriate amount. The present invention relates to a particle size distribution measuring device that can be automatically controlled.

[0002]

2. Description of the Related Art Conventionally, as a device for measuring the particle size distribution of various powder samples, a particle size distribution measuring device using an image processing system has been used. This particle size distribution measuring device generally uses a sample conveyed by a conveying device such as a belt conveyor,
Image data is obtained by imaging with a CCD camera (area sensor camera or line sensor camera), and based on the image data, a control device such as a personal computer calculates the number of particles of the sample, the particle size of each particle, and the like. The apparatus is configured to calculate a particle size distribution from the calculation result, display the particle size distribution on an image monitor, and print the particle size distribution on a printer.

[0003] In such a particle size distribution measuring apparatus, a true particle size distribution cannot be obtained due to, for example, overlapping of particles. Therefore, it is necessary to adjust a supply amount of a sample to an imaging unit of a CCD camera. The adjustment of the supply amount is performed by manually adjusting the output of the transfer device, or, when the output of the transfer device is fixed, by adjusting the amount of the sample to be introduced into the transfer device.

[0004]

However, when the supply amount of the sample is manually adjusted by adjusting the output of the transfer device, it is necessary for the operator to adjust the output of the transfer device while visually observing the degree of transfer of the sample. In addition to the sensory element of the operator's judgment, there may be cases where the true particle size distribution of the sample cannot be obtained, for example, the measurement data may vary due to an operator's judgment mistake, etc. Since adjustment work is required, there is a problem that workability of the measurement work is inferior.

In addition, when adjusting the amount of the sample to be introduced into the transfer device, the workability of the measurement work is inferior, for example, it is necessary to control the amount of the sample to be introduced. Depending on the operating condition of the transfer device, this sample
There is a problem that it is not always possible to uniformly supply a predetermined amount to the imaging unit of the D camera, and it is difficult to make the supply amount of the sample to the imaging unit uniform.

The present invention has been made in view of such circumstances, and an object of the invention described in claim 1 is to automatically control a supply amount of a sample to an imaging unit to make the amount uniform. It is an object of the present invention to provide a particle size distribution measuring device capable of improving measurement accuracy and workability and simplifying the configuration.
A second object of the present invention is to provide a particle size distribution measuring device capable of automatically controlling the supply amount of a sample with high accuracy and improving measurement accuracy and workability in addition to the object of the first embodiment. The purpose of the invention described in claim 3 is to provide
In addition to the object of the invention described above, it is another object of the present invention to provide a particle size distribution measuring device capable of further simplifying automatic control of a sample supply amount.

[0007]

In order to achieve the above object, according to the present invention, the particle size distribution of a sample is determined by an image conveyed by a conveying means operated by a driving source and picked up by an image pickup device. In the particle size distribution measuring device to be measured, the imaging state of each image data is detected based on the captured image data, and the driving source is controlled based on the detected imaging state to control the driving source. It is characterized by comprising control means for adjusting the supply amount.

[0008] With this configuration, an image of the sample conveyed by the conveying means operated by the driving source is captured by the image pickup device, and the image data is subjected to, for example, binarization processing by the control means, so that each image is obtained. The imaging state such as the number of particles in the data and the density information is detected. The control means monitors the detected imaging state and compares it with a preset reference state.For example, when the number of detected particles is equal to or less than the reference value, it is determined that the supply amount of the sample has decreased. By controlling the operating state of the drive source of the transfer means, the transfer amount of the sample is increased.

When the number of detected particles exceeds the reference value, it is determined that the supply amount of the sample has increased, and the transport amount by the transport means is reduced. As a result, the supply amount of the sample to the imaging unit of the imaging device is automatically adjusted, an image is captured with a uniform amount of the sample, and the measurement accuracy is improved, and manual adjustment of the supply amount is not required. become,
The workability of the measurement work is improved. Further, since the supply amount is automatically controlled based on the image data required for the particle size distribution measurement, it is not necessary to set a new factor for the automatic control, and the configuration of the measuring apparatus itself is simplified.

[0010] According to a second aspect of the present invention, when the image capturing state of a predetermined number of continuous image data out of the image data captured by the image capturing device becomes a preset image capturing state, the control means controls the drive. Outputting a predetermined control signal to the source. With this configuration, the control unit controls the driving source of the transport unit based on the imaging state of the image data of a predetermined number of continuous frames, so that the driving source is controlled by a single change in the imaging state. Therefore, the supply amount of the sample to the imaging unit is accurately controlled.

Further, the invention according to claim 3 is characterized in that the image pickup state is density information or circularity of image data. With this configuration, since the imaging state is determined based on the gray level information or the circularity of each image data captured by the particle size distribution measuring device, it is not necessary to provide a special determination factor, and the transport unit Automatic control of the drive source is simplified.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. 1 to 3 show an embodiment of a particle size distribution measuring apparatus according to the present invention. FIG. 1 is a schematic configuration diagram, FIG. 2 is a flowchart showing an example of the operation, and FIG. 3 shows an example of an imaging state. FIG.

In FIG. 1, a particle size distribution measuring apparatus 1 includes a vibrating feeder 2 as a transporting means for transporting a sample S in the direction of an arrow by a power supply from a driving source 3, and a sample S falling from the vibrating feeder 2. An image pickup device 4 for picking up an image, and a control device 5 as control means for taking in image data taken by the image pickup device 4, performing various arithmetic processes based on the image data, and outputting the results. And so on.

The drive source 3 of the vibration feeder 2 has an AC power supply 3a and a variable resistor 3b connected to the output side of the AC power supply 3a. By adjusting the resistance value of the variable resistor 3b, The voltage and current (electric power) supplied to the vibration feeder 2 change, and for example, the amplitude of the vibration feeder 2 is varied.

The image pickup device 4 comprises, for example, a monochrome image pickup device 6 (CCD area sensor camera or line sensor camera) and a halogen lamp which is arranged opposite to the image pickup device 6 and connected to an illumination power supply 8. The imaging device 6 captures a grayscale image of the sample S by illumination from the halogen lamp 7.

The control device 5 includes an image capturing device 9 for capturing an image of the image capturing device 6, a computer 10 connected to the image capturing device 9 for performing arithmetic processing on captured image data, Image monitor 11 for displaying the result and printer 12 for printing the result
And an input unit 13 including a keyboard and a mouse.

The computer 10 has a CPU 14 and an R
A still image from the imaging device 6 input from the image capturing device 9 is stored in the ROM 16
The number of particle groups, the area, the particle size, and the volume of each particle R are calculated from the grayscale information in the still image by performing the binarization processing according to the program stored in the. Then, the computer 10 obtains the particle size distribution based on the volume ratio of each still image and the like, calculates the particle size distribution of the sample S from each particle size distribution, and outputs the result to the image monitor 11 or the printer 12.
And controls the driving source 3 by determining the supply amount of the sample S based on the density information of the image data as described later.

Next, an example of the operation of the particle size distribution measuring device 1 will be described with reference to the flowchart of FIG. Note that the flowchart of FIG.
Since the calculation and the like of the particle size distribution in the particle size distribution measuring device 1 are performed by the same method as the conventional method, the description is omitted.

In FIG. 2, when the measurement program for the sample S is started (S100), parameters such as the number of frames a, the criterion b, the upper and lower allowable widths α1, α2, and the number Q of determination end loops are set (S101). . Among these parameters, the number of frames a is the monitoring number of still image data continuously captured by the image capturing device 9, the criterion b is a criterion value for controlling the operation of the vibration feeder 2,
α1 and α2 are a lower limit allowable width and an upper limit allowable width with respect to the determination criterion b, and the determination end loop number Q is a parameter serving as a reference for ending the measurement. These are input by the input unit 13 of the control device 4 and stored in the RAM of the computer 10.
15 and so on.

When the parameters are set in step S101, first, the image pickup device 6 of the image pickup apparatus 4
Is captured by the image capturing device 9 (S102), and this image data is
The PU 14 performs a binarization process (S103). By this binarization processing, the image data is converted into the grayscale information of “1” and “0”, and the grayscale ratio ni of “1” and “0” is calculated (S104).

When the shading ratio ni is calculated, the total shading ratio N of the image data within the frame count i (the number of image data) is calculated, and "1" is added to the frame count i (S105). Next, when the frame count i is “a”
It is determined whether or not the image data of the number of frames set in step S101 is “NO” (S106), ie, if the image data of the frame number a set in step S101 is not captured, the process returns to step S102, and the next image data is It is captured. If "YES" in the determination S106, that is, a continuous image data is taken in and the total density ratio N of each image data is calculated, the continuous frame a
The averaged light-and-shade ratio n based on the image data in is calculated (S107). As the density ratio n, for example, a total value or a deviation value of each density ratio ni of a image data can be substituted.

After the calculation of the contrast ratio n, it is determined whether or not the contrast ratio n is less than a criterion b-α1 (S1).
08). If "YES" in this determination S108,
That is, as shown in state 1 in FIG. 3, when the number of particles R in each image data (frame) is small overall, the count number q corresponding to the determination end loop number Q is set to plus 1 (S109). At the same time, a control signal is output to the driving source 3 of the vibration feeder 2 to adjust the resistance value of the variable resistor 3b to increase the amplitude (that is, the transport speed) of the vibration feeder (S110). Thereby, the vibration feeder 2
The amount of the sample S conveyed at the time increases, and the amount of the sample S dropped and supplied to the imaging unit of the image imaging device 4 increases.

On the other hand, if "NO" in the judgment S108,
It is determined whether the shading ratio n exceeds the criterion b + α2 (S111). If “YES” in the judgment S111, that is, if the number of particles R in each image data is large as a whole as shown in the state 3 in FIG. 3, the control signal is sent to the driving source 3 of the vibration feeder 2. And output
By adjusting the resistance value of the variable resistor 3b, the amplitude (that is, the transport speed) of the vibration feeder 2 is reduced (S112). Thereby, the amount of the sample S conveyed by the vibration feeder 2 decreases, and the amount of the sample S dropped and supplied to the imaging unit of the image imaging device 4 decreases.

If the determination in step S111 is "NO", that is, as shown in state 2 in FIG.
In the case of -α1) to (b + α2), it is determined that the drop supply amount of the sample S is appropriate, and the operation state is maintained without outputting a control signal to the drive source 3 of the vibration feeder 2;
It is determined whether the measurement is completed (S115). When the transport speed is increased in step S110, Q <q
Is determined (S113), and in this determination S111, "N
In the case of “O”, q = 0 (S114) and step S
The process proceeds to 115, and if “YES” in the determination S113, a series of programs ends (S117).

That is, in steps S113 and S114, q is incremented by one for each loop if n <b-α1 is continued, and is initialized to “0” if n <b−α1, and n <b−α.
If α1 continues the Q loop, that is, if the density ratio does not increase even if the transport speed is increased, it is determined that there is no sample S, and the measurement is terminated. The determination of the end of the measurement is not limited to the above example. For example, the determination can be made by manual end by an operator's operation or by automatic end due to elapse of a set time.

If "NO" in the judgment S111, if the transport speed is reduced in the step S112, or if the step S114 is passed, the step S1 is executed.
It is determined whether or not the measurement has been completed by moving to step S15. If the determination in step S115 is "NO", the total density ratio N and the frame count i are set to "0" (S116), and step S116 is performed.
Return to 102. If all the measurements of the sample S have been completed, “YES” is determined in the determination S115, and the series of programs is ended (S117).

In the above flowchart, whether or not n> b + α2 is determined in step S111, step S111 can be omitted. In this case, for example, if the concentration is extremely high, the particles may overlap with each other, so that the data due to the overlap can be discarded, and the measurement data as the image data for the particle size distribution measurement instead of the data of the density ratio is used. Reliability can be improved.

As described above, in the particle size distribution measuring apparatus 1 of the above embodiment, the density ratio n obtained from the image data picked up by the image pick-up device 3 is compared with the preset judgment criterion b, When the ratio n becomes smaller than the criterion b-α1, for example, the control device 5 sends the driving source 3 of the vibration feeder 2
To increase the amplitude of the vibration feeder 2 to increase the transport amount of the sample S, and when the density ratio n exceeds the criterion b + α2, controls the drive source 3 to control the vibration feeder. In order to reduce the transport amount of the sample S by reducing the amplitude of 2, the transport amount of the sample S dropped and supplied to the imaging unit of the image capturing device 4 can be automatically controlled.

As a result, the sample S dropped and supplied to the imaging unit
In the case where the amount of the sample S fluctuates beyond a predetermined value, the amount can be automatically adjusted, and during the measurement period, a uniform amount of the sample S can be supplied to the imaging unit, and the particle size distribution Measurement accuracy can be greatly improved. In particular,
Since the supply amount is controlled based on the continuous image data of the predetermined number of frames a, the control based on the sporadic variation in the supply amount is prevented, and the supply amount of the sample S dropped to the imaging unit is reduced. Can be made more uniform (averaged) during the measurement period, and the sample S can be supplied with higher accuracy.

The above parameters a, b, α1, α
2, a = 50 frames, b = 5%, α1 = 2%, α2
= 1%, and an experiment of particle size distribution measurement was performed. As a result, it was confirmed that the supply amount of the sample S could be made uniform and the above-described respective effects could be obtained.

Further, in the particle size distribution measuring apparatus 1 of the above embodiment, it is not necessary to visually monitor the amount of the sample S dropped and supplied to the image pickup section of the image pickup apparatus 4, and the output of the vibration feeder 2 is not required. Eliminates the need to manually adjust each time, making measurement work easy and quick,
The workability can be improved, for example, the measurement can be automated. Further, a density ratio n of each image data necessarily obtained by the image processing type particle size distribution measuring device 1 is calculated, and the calculated density ratio n and a preset determination criterion b
Since the supply amount of the sample S is determined by comparing with the measurement device 1, it is not necessary to separately set a new factor for the determination, and the automatic control program for the supply amount can be simplified. It is possible to form itself at low cost.

Further, since the state of the sample S in the image pickup section of the image pickup device 6 is automatically monitored, it is not necessary for the operator to constantly monitor the measurement apparatus 1, so that the measurement can be completely unmanned and the measurement work can be performed. It is also possible to obtain an additional operation and effect that the time and man-hour can be reduced.

In the above embodiment, the density ratio n of the image data is used to determine the supply amount of the sample S. However, the present invention is not limited to this.
Alternatively, the circularity or the number of particles can be used. 4 to 6 show an embodiment in which a circularity (a shape index representing a degree of macroscopic flatness) is used, FIG. 4 is a flowchart similar to FIG. 2, and FIGS. 5 and 6 are explanatory diagrams thereof. It is.
Hereinafter, points that are particularly different from the flowchart of FIG. 2 will be described in detail.

As shown in FIG. 4, this flowchart is
In step S202, an image is captured, and in step S203
After the binarization process, the perimeter W1 of the particle R is measured (S
204). This peripheral length W1 corresponds to the image data shown in FIG.
In the case of an elliptical particle R as shown in (a), it is measured as the length around it. When the perimeter W1 is measured,
Next, a circle-equivalent circumference W2 is calculated (S205). The circle-equivalent circumference W2 is obtained by converting the projected area of the imaging particle R shown in FIG. 5A into a perfect circle shown in FIG. 5B. This is done by measuring the perimeter of this perfect circle.

Then, the circularity Ei is calculated from the obtained particle circumference W1 and the circle-equivalent circumference W2 (S206). This circularity Ei is expressed as Ei = W2 / W1 (0 <Ei <
It is calculated in 1). Next, the number ni of particles in the image data is counted (S207). Then, the total circularity f and the total number n of particles are calculated, and “1” is added to the frame count i (S208).

Thereafter, it is determined whether or not the number of frames is a predetermined number a (S209), and the total circularity f of the predetermined number of frames a is determined.
Is calculated, the circularity E in the continuous frame a is calculated.
Is calculated, for example, in the same manner as the above-mentioned shading ratio n (S210). Thereafter, steps S211 to S220 similar to steps 108 to S117 in the flowchart of FIG. 2 are executed based on the calculated circularity E, the determination criterion e, the lower limit allowable width α1, and the upper limit allowable width α2. In this case, the determination of the end of the measurement in steps S216 and S217 is performed when the circularity continues to be high.

When the particles R are agglomerated or overlap, the shape of the imaging particles becomes complicated, and in reality, there are two particles R1 and R2 as shown in FIG. Nevertheless, in image processing, as shown in FIG.
Treated as one particle R. However, since the circularity E changes in accordance with the shape, by monitoring the circularity E, the concentration (supply amount) of the particles R suitable for measuring the particle size distribution can be obtained.

Also in this embodiment, the conveying speed of the vibration feeder 2 can be increased or decreased based on the circularity E of each image data, and the same operation and effect as in the above embodiment can be obtained. When the number of particles is used as a criterion, the same operation and effect can be obtained, and since the counting of the number of particles is relatively easy, the control of the vibration feeder 2 can be further simplified. The effect is also obtained.

In the above embodiment, the case where the upper and lower allowable widths α1 and α2 with respect to the criterion are different has been described. However, the same allowable width can be used.
By setting a plurality of determination criteria, for example, the conveyance speed of the vibration feeder 2 can be controlled by a plurality of step controls such as a low speed, a medium speed, and a high speed. Further, in the above embodiment, the amplitude of the vibration feeder 2 is controlled by changing the resistance value of the variable resistor 3b of the driving source 3 of the vibration feeder 2. For example, the frequency and voltage of the AC power supply 3a are changed. By doing so, it is also possible to control the amount of sample supplied from the vibration feeder 2.

In the above embodiment, the vibration feeder 2 is used as the transfer device. However, an appropriate transfer device such as a belt conveyor may be used.
It is also possible to use a solid-state imaging device other than the CD system, such as a MOS system or a CID system. In addition, the flowcharts and the like in the above embodiments are also examples, and it is needless to say that various changes can be made without departing from the gist of each invention according to the present invention.

[0041]

As described in detail above, according to the first aspect of the present invention, the sample is imaged by the imaging device, the imaging state in the image data is detected by the control means, and the detected imaging is performed. Since the state is compared with a preset reference state and the operation of the driving source of the transport unit is controlled, the amount of the sample supplied to the imaging unit can be made uniform, and the particle size distribution can be measured accurately. And the workability of the measurement work can be improved, and the configuration for control can be simplified.

According to the second aspect of the present invention, in addition to the effect of the first aspect, the control means controls the drive source of the transport means based on the imaging state of the image data of a predetermined number of continuous frames. Since the control is performed, the supply amount of the sample to the imaging unit of the imaging device can be more accurately controlled, such that the drive source is not controlled by a single change in the imaging state.

According to the third aspect of the invention, in addition to the effects of the second aspect, the imaging state is determined based on the density information or circularity of each image data imaged by the particle size distribution measuring device. Therefore, it is not necessary to provide a special determination factor, and it is possible to simplify the automatic control of the driving source of the transporting means.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a particle size distribution measuring device according to the present invention.

FIG. 2 is a flowchart showing an example of the operation.

FIG. 3 is an explanatory diagram showing an example of the imaging state.

FIG. 4 is a flowchart showing another operation.

FIG. 5 is an explanatory view of the same.

FIG. 6 is another explanatory view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Particle-size distribution measuring device 2 Vibration feeder 3 Drive source 3a AC power supply 3b Variable resistor 4 Image pickup device 5 Control device 6 Image pickup device 7 Halogen lamp 9 Image capture device 10 Computer 11 Image monitor 12 Printer 13 Input unit 14 CPU 15 RAM 16 ROM S Sample n Shading ratio E Roundness

Claims (3)

[Claims] 1. A particle size distribution measuring apparatus for measuring a particle size distribution of a sample based on an image conveyed by a conveying means operated by a driving source and picked up by an image pickup device, wherein an image pickup state of each image data is detected based on the picked up image data. A particle size distribution measuring device comprising: a control unit that controls the driving source based on the detected imaging state and adjusts a supply amount of a sample to be imaged by an imaging device by a transport unit. 2. The image processing apparatus according to claim 1, wherein said control means sends a predetermined control signal to a driving source when an image capturing state of a predetermined number of continuous image data among image data captured by the image capturing device becomes a preset image capturing state. 2. The particle size distribution measuring device according to claim 1, wherein the particle size distribution is output. 3. The particle size distribution measuring apparatus according to claim 2, wherein the imaging state is density information or circularity of image data.