JP2002131015A - Position measuring apparatus of three-dimensional particle and speed measuring apparatus thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure position and speed of three-dimensional particle in an measured area in a three-dimensional way by using single imaging means. SOLUTION: In a position measuring apparatus of three-dimensional particle, He-Ne laser 1 and Ar-ion laser 2 are used to change continuously the intensity of the laser 1, 2 in the z-axial direction by ND filters 8, 9 respectively. The laser 1, 2 are synthesized by a miller 10 and a beam-splitter 11 to radiate into a measured area 12. In the area 12, a CCD camera 13 is arranged in the direction. Scattered light from a micro particle responds to an output level ratio of two colors, so that a position in the direction is obtained based on the ratio and a three-dimensional coordinate is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device for three-dimensionally measuring the position and velocity of particles in a measurement area.

[0002]

2. Description of the Related Art Conventionally, in order to measure the three-dimensional position and velocity of fine particles, a plurality of CCD cameras are three-dimensionally arranged and images of a measurement area are measured from different angles. And devices for measuring speed are used.

[0003] Such a conventional measuring apparatus requires a complicated optical system, and requires image processing for converting output images from a plurality of CCD cameras into a three-dimensional image.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a measuring apparatus which measures the position and velocity of a fine particle in a measuring area three-dimensionally using one image pickup device.

[0005]

According to the first aspect of the present invention, there is provided a three-dimensional particle position measuring apparatus for measuring a three-dimensional position of a measurement area represented by coordinates on x, y, and z axes perpendicular to each other. And a first and second light source for emitting light of different first and second colors, and a light intensity distribution different from each other along the z-axis. Light intensity adjusting means for adjusting the ratio so as to monotonously change,
Optical means for superimposing light from the first and second light sources passing through the light intensity adjusting means and emitting light synthesized in the y-axis and z-axis directions in the x-axis direction toward the measurement region;
An imaging unit that is directed to the measurement region from an arbitrary direction that does not coincide with the x-axis and y-axis directions, and captures a two-dimensional image of x-axis and y-axis coordinates from the measurement region; Z-axis position calculation means for obtaining position information in the z-axis direction of particles in the measurement area based on the output level of the pixel and the output ratio of the first and second colors of each pixel;
A three-dimensional position output for outputting a three-dimensional coordinate position of the particle in the measurement area based on the position information in the z-axis direction obtained by the z-axis position calculating means and the position information in the x and y directions obtained by the imaging means; And means.

According to a second aspect of the present invention, in the three-dimensional particle position measuring apparatus according to the first aspect, the light intensity adjusting means includes:
N having different intensity distributions continuously in the z-axis direction
It is a D filter.

According to a third aspect of the present invention, in the three-dimensional particle position measuring apparatus according to the second aspect, the ND filter includes
Dyes respectively corresponding to the first and second colors of the first and second light sources are inserted into a triangular prism-shaped case whose thickness changes in the axial direction.

According to a fourth aspect of the present invention, in the three-dimensional particle position measuring device according to the first aspect, the imaging means is oriented in the z-axis direction and takes a two-dimensional image of x and y coordinates. It is assumed that.

According to a fifth aspect of the present invention, there is provided a method for measuring the number of particles in a measurement area represented by coordinates on x, y, and z axes perpendicular to each other.
A three-dimensional particle velocity measuring device for measuring a three-dimensional velocity,
First and second light emitting first and second colors different from each other
A second light source, and light intensity adjusting means for adjusting the light of the first and second light sources to have different light intensity distributions along the z-axis and to change the ratio monotonically; Optical means for superimposing light from the first and second light sources passing through the light intensity adjusting means and emitting light synthesized in the y-axis and z-axis directions in the x-axis direction toward the measurement region; It is directed to the measurement region from an arbitrary direction that does not coincide with the x-axis and y-axis directions.
Imaging means for imaging a two-dimensional image, z of particles in a measurement area based on an output level of each pixel obtained from the imaging means, and an output ratio of the first and second colors of each pixel.
A z-axis position calculator for obtaining position information in the axial direction; and a position in the measurement area based on position information in the z-axis direction obtained from the z-axis position calculator and position information in the x and y directions obtained from the imaging unit. A three-dimensional position output unit for outputting the three-dimensional coordinate position of the particle, and the same particle based on the time-series data of the three-dimensional position information obtained from the three-dimensional position output unit. 3 based on changes in
Velocity measuring means for measuring a three-dimensional particle velocity.

According to a sixth aspect of the present invention, in the three-dimensional particle velocity measuring apparatus of the fifth aspect, the light intensity adjusting means comprises:
N having different intensity distributions continuously in the z-axis direction
It is a D filter.

According to a seventh aspect of the present invention, in the three-dimensional particle velocity measuring apparatus according to the sixth aspect, the ND filter includes
Dyes respectively corresponding to the first and second colors of the first and second light sources are inserted into a triangular prism-shaped case whose thickness changes in the axial direction.

According to an eighth aspect of the present invention, in the three-dimensional particle velocity measuring apparatus of the fifth aspect, the imaging means is oriented in the z-axis direction and takes a two-dimensional image of x, y coordinates. It is assumed that.

[0013]

FIG. 1 is a block diagram showing an entire configuration of an optical system of a particle position measuring apparatus according to a first embodiment of the present invention. In the figure, a helium neon laser (He-Ne laser) 1 is a first light source that emits 633 nm red light. Argon ion laser (Ar ⁺
Laser) 2 is 488 nm (blue) and 514 nm (green)
A second light source that emits the two colors of light. The green emission light among the emission light from the argon ion laser 2 is cut by the color filter 3, and only the blue light is output.
In order to make the intensity of the output light of the helium neon laser 1 and that of the argon ion laser 2 equal, the light intensity of the argon ion laser 2 is adjusted in advance. The emission direction (rightward direction on the paper) of these laser light sources is defined as the x-axis direction, the direction perpendicular to the paper surface is defined as the y-axis direction, and the downward direction on the paper surface is defined as the z-axis direction. As shown, slits 4 and 5, collimating lenses 6 and 7, and continuous ND filters 8 and 9 are provided on the emission side of the laser light source, respectively. Collimating lenses 6 and 7
Have the same diameter, for example, 50 mm in diameter. The ND filters 8 and 9 adjust the light of the first and second light sources so as to have different light intensity distributions continuously along the z-axis and to change the ratio when superimposed monotonously. It constitutes strength adjusting means. The ND filters 8 and 9 are formed, for example, by arranging two glass plates at a fixed angle so that the cross section becomes an acute triangular prism shape, and making the inside thereof a space, which is filled with water containing a dye. Can be configured. The ND filter 8 is filled with dye water colored red corresponding to the color of the light source, and the ND filter 9 is filled with dye water colored blue. As shown, the ND filters 8 and 9 are symmetrically arranged along the z-axis direction so that the light attenuation rates are different. As shown in the figure, the mirror 10 is arranged on the optical axis on the side of the argon ion laser 2 at an angle of 45 ° from the optical axis (x-axis), and the light is reflected toward the beam splitter 11. The beam splitter 11 is a beam splitter in which a separation surface is disposed at an angle of 45 ° along an optical axis that transmits light from the helium neon laser 1, and combines the light in the y-axis and z-axis directions perpendicular to each other to form a light source It is light. The emission side of the beam splitter 11 is a measurement area 12. Here, the mirror 10 and the beam splitter 11 superimpose the light from the two light sources and make y
The light combined in the x-axis and z-axis directions is directed toward the measurement region 12 by x
Optical means for emitting light in the axial direction is configured.

Now, a two-dimensional CCD toward the measurement area 12
The camera 13 is arranged so that an image in the xy directions can be obtained. The CCD camera 13 is a video camera for obtaining a normal color image.
It is preferable to use a CCD camera including a CD. FIG.
As shown in FIG.
14 is connected, and the image is temporarily stored in the VTR 14. Then, the image signal reproduced by the VTR 14 is transferred to the image capture board 15.
Is input to the personal computer 16 via. The personal computer 16 has a display unit 17 and an input unit 18.
Is connected. The personal computer 16 separates a continuous image signal obtained from the image capturing board 15 into two primary colors of R and B for each screen as described later and converts it into coordinates in the z-axis direction based on the ratio. It is. Note C
The CD camera 13 can be arranged at an angle from the z-axis, but it is necessary that the CD camera 13 does not coincide with the x-axis or the y-axis.

Next, the operation principle of this embodiment will be described. FIG. 3 is a graph showing the relationship between the light intensity of red (R) and blue (B) emitted from the beam splitter 11 to the measurement region 12 and the position on the z-axis. 3 as mentioned above
The optical system of the three-dimensional position measuring device
Axis, the direction perpendicular to the paper surface is the y-axis, and the downward direction to the paper surface is z.
With respect to the axis, as shown in FIG. 3, the red light increases as the value in the z-axis direction increases. Conversely, the level of blue intensity decreases as the value increases in the z-axis direction.

The intensity distribution at an arbitrary point in the measurement area 12 based on the light emitted from the helium neon laser 1 is represented by I
_R = I _R (x, y, z), and argon ion laser 2
The intensity distribution of an arbitrary point of the measurement region based on the light emitted from the _{I B = I B (x,} y, z) When they become known values. Assuming that the intensity ratio η at the same position is I _R / I _B ,
The intensity ratio η is a value determined by the position on the z-axis regardless of the coordinates of x and y. The scattered light from the particles in the measurement area also maintains this intensity ratio. Accordingly, two components of red and blue are extracted from the scattered light, and the intensities thereof are denoted by Γ _R ,
When gamma _B, its value I _R, corresponds to I _B, the ratio gamma _R / gamma _B is equal to eta. Therefore, the position of the particle in the z direction can be detected from this value.

Next, the processing in the personal computer 16 will be described with reference to the flowchart of FIG.
When the operation is started, first, image data is taken from the CCD camera 13 in step S1. As described above, a two-dimensional image in the x and y directions is obtained from the CCD camera 13. This is temporarily recorded on the VTR 14, read out sequentially, and divided into three colors of R, G, and B. Next, in step S4, except for data whose luminance value is equal to or less than a predetermined threshold,
The following processing is performed on particles from which a signal having a predetermined luminance value or more is obtained. Here, since the helium neon laser 1 and the argon ion laser 2 are used as the light sources, the ratio η (x, x, x) is calculated for each coordinate by using only two color image data of red (R) and blue (B). y) is calculated (step S3). η (x, y) = I R (x, y) / I B (x, y)

Since the intensity ratio is a monovalent function in the z-axis direction as shown in FIG. 4, the coordinates of the z-axis can be calculated from the intensity ratio. Actually, particles to be used are attached to a glass plate or the like in advance, installed on a parallel moving table, and moved in the z-axis direction. Then, from the ratio of the two-color images obtained at that time and the value of the z-axis on the translation table at that time,
Prepare a calibration curve. In this way, it is possible to calculate the accurate z coordinate by compensating the color of the fine particles. This calibration is preferably performed in advance at a plurality of coordinate points on the x-axis and the y-axis. Then, the output ratio thus obtained is converted into a z-axis (step S4). And step S
At 5, a three-dimensional display is performed. Next, speed information conversion processing is performed in a routine S6. The three-dimensional speed information data thus obtained is displayed on the display unit 17 in step S7. Then, the process returns to step S1, where the next image is fetched, and the same process is repeated.

The speed information conversion processing of the routine S6 is performed, for example, by Shigeru Nishio, Workshop of the Visualization Information Society, June 1998, 9
Month and January 1999 text, "Here is a different PIV
Principles ", P15-P18, JSME Transactions, Vol. 55, No. 509, P107-P114, Toshio Kobayashi, etc.
As shown in "Development of a real-time digital image measurement system for a two-dimensional flow field", it can be performed by using a well-known particle tracking method or a correlation method. In the particle tracking method, the movement of particles on a visualized image is sequentially tracked, and the flow velocity is obtained from the movement amount. In the particle tracking method, after acquiring an image, a particle image is recognized, particle numbering (labeling), particle tracking, and velocity vector calculation are performed to obtain velocity information. In the particle tracking method, for example, a four-time tracking method is widely known.
A combination in which the position change of the particle at four times is closest to a straight line is selected as a correct moving route using a series of images. In this method, since only the position information of the particles is used, as the time advances, the particle candidates of the movement destination are narrowed down, and finally, the movement path of the particles is determined. In the correlation method, a region where an image substantially equal to the region of interest can be obtained is determined using the correlation coefficient, and particles can be tracked by determining a corresponding particle from this region.

As described above, according to the present embodiment, three-dimensional particle positions can be measured using one two-dimensional CCD camera. Also, speed information can be detected based on this position data, and the configuration of the optical system can be extremely simplified. Here, the personal computer 16
In steps S2 to S4, position information of particles in the measurement area in the z-axis direction is obtained based on the output level of each pixel obtained from the imaging unit and the output ratio of the first and second colors of each pixel. The z-axis position calculation means is configured, and in step S5, a three-dimensional position in the measurement area is determined based on the position information in the z-axis direction obtained by the z-axis position calculation means and the position information in the x and y directions obtained by the imaging means. The function of the three-dimensional position output means for determining and outputting the coordinate position is achieved. The routine S6 constitutes velocity measuring means for tracking the same particle based on the time series data obtained from the three-dimensional position output means and measuring the velocity of the particle. FIG. 6 and FIG. 7 are diagrams showing an example of the velocity vectors of the particles thus obtained as viewed from different directions.

In this embodiment, a helium neon laser and an argon ion laser are used, but the argon ion laser is 488 nm (blue) and 514 nm.
In order to emit two colors of (green), this is decomposed by a color filter and used as a light source of two colors, thereby omitting the helium neon laser, and using only an argon ion laser as the first and second light sources. be able to. Also in this case, the ND filter uses dye water corresponding to each color, and uses two colors of blue (B) and green (G) among the outputs of the CCD camera 13. In this way, three-dimensional position information can be obtained by emitting light with two-dimensional coordinates having different intensity distributions in the z-axis direction with the same configuration as in FIGS.

[0022]

As described above in detail, according to the first to fourth aspects of the present invention, three-dimensional position information of particles can be obtained by using an imaging means for imaging a two-dimensional image.
Further, according to the invention of claims 5 to 8, three-dimensional velocity information can be obtained based on the three-dimensional coordinate data, and in any case, an excellent effect that the configuration of the optical system can be extremely simplified. can get.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an optical system portion of a three-dimensional particle position and particle velocity measuring device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a signal processing system according to the present embodiment.

FIG. 3 is a graph showing a change in relative light intensity with respect to the z-axis in the present embodiment.

FIG. 4 is a graph showing a change in intensity ratio with respect to the z-axis in the present embodiment.

FIG. 5 is a flowchart showing the operation of the present embodiment.

FIG. 6 is a graph (part 1) showing an example of a three-dimensional velocity measurement result obtained by the three-dimensional particle velocity measuring device of the present embodiment.

FIG. 7 is a graph (part 2) showing an example of a three-dimensional velocity measurement result obtained by the three-dimensional particle velocity measuring device of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Helium neon laser 2 Argon ion laser 3 Color filter 4,5 Slit 6,7 Collimating lens 8,9 ND filter 10 Mirror 11 Beam splitter 12 Measurement area 13 CCD camera 14 VTR 15 Image capture board 16 Personal computer 17 Display part 18 Input section

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaaki Kawabashi 5-11-11 Suzuya, Yono-shi, Saitama (72) Inventor Yukinari Sato 2-1 Shimizu, Suita-shi, Osaka F-term in Nippon Kanomax Co., Ltd. Reference) 2F065 AA04 BB15 FF42 GG05 HH01 JJ03 JJ26 LL21 LL22 LL28 LL46 MM02 QQ23 QQ26 5L096 AA02 AA09 BA08 CA04 CA17 CA18 FA15 FA39 FA69 HA05

Claims (8)

[Claims] 1. A three-dimensional particle position measuring device for measuring a three-dimensional position of a measurement area represented by coordinates on x, y, and z axes perpendicular to each other, wherein the first and second colors are different from each other. First, which emits light of
A second light source, and light intensity adjusting means for adjusting the light of the first and second light sources so as to have different light intensity distributions along the z-axis and to change the ratio monotonically; Optical means for superimposing light from the first and second light sources passing through the light intensity adjusting means and emitting light synthesized in the y-axis and z-axis directions in the x-axis direction toward the measurement region; An imaging unit that is directed to the measurement region from an arbitrary direction that does not match the x-axis and y-axis directions and captures a two-dimensional image of x-axis and y-axis coordinates from the measurement region; Z-axis position calculating means for obtaining position information of particles in the measurement region in the z-axis direction based on an output level of a pixel and an output ratio of the first and second colors of each pixel; The position information in the z-axis direction obtained by the calculation means and the imaging means It is x, based on the position information in the y-direction, 3, characterized in that it has a, a three-dimensional position output means for outputting the three-dimensional coordinate position of the particle in the measurement region
Dimensional particle position measurement device. 2. The three-dimensional particle position measuring apparatus according to claim 1, wherein said light intensity adjusting means is an ND filter having different intensity distributions continuously in the z-axis direction. 3. The ND filter in which dyes respectively corresponding to the first and second colors of the first and second light sources are inserted in a triangular prism-shaped case whose thickness changes in the z-axis direction. The three-dimensional particle position measuring device according to claim 2, wherein: 4. The imaging means is directed in a z-axis direction,
2. The three-dimensional particle position measuring device according to claim 1, wherein the three-dimensional particle position measuring device captures a two-dimensional image of x and y coordinates. 5. A three-dimensional particle velocity measuring device for measuring a three-dimensional velocity of a particle in a measurement area represented by coordinates on x, y, and z axes perpendicular to each other, comprising: The first one that emits light of two colors
A second light source, and light intensity adjusting means for adjusting the light of the first and second light sources so as to have different light intensity distributions along the z-axis and to change the ratio monotonically; Optical means for superimposing light from the first and second light sources passing through the light intensity adjusting means and emitting light synthesized in the y-axis and z-axis directions in the x-axis direction toward the measurement region; An imaging unit that is directed to the measurement region from an arbitrary direction that does not match the x-axis and y-axis directions and captures a two-dimensional image of x-axis and y-axis coordinates from the measurement region; Z-axis position calculating means for obtaining position information of particles in the measurement region in the z-axis direction based on an output level of a pixel and an output ratio of the first and second colors of each pixel; The position information in the z-axis direction obtained by the calculation means and the imaging means Three-dimensional position output means for outputting a three-dimensional coordinate position of the particle in the measurement area based on the obtained position information in the x and y directions, and time-series data of the three-dimensional position information obtained from the three-dimensional position output means. A three-dimensional particle velocity measuring device, comprising: a velocity measuring unit that traces the same particles based on the position of the traced particles based on a change in the position of the traced particles. 6. The three-dimensional particle velocity measuring apparatus according to claim 5, wherein said light intensity adjusting means is an ND filter having different intensity distributions continuously in the z-axis direction. 7. The ND filter in which dyes respectively corresponding to the first and second colors of the first and second light sources are inserted into a triangular prism-shaped case whose thickness changes in the z-axis direction. The three-dimensional particle velocity measuring device according to claim 6, wherein 8. The imaging means is oriented in a z-axis direction,
6. The three-dimensional particle velocity measuring apparatus according to claim 5, wherein the three-dimensional particle velocity measuring apparatus captures a two-dimensional image of x and y coordinates.