JPH0312524A - Method for visualizing emission intensity distribution - Google Patents

Abstract

PURPOSE:To improve the working efficiency and accuracy of measurement by calculating the emission intensity distribution of the measuring section satisfying the relation of specific equation from the predetermined contribution rate of emitted light and the resulted projection data from respective measuring directions by using a successive approximation calculation method. CONSTITUTION:A projection data collecting part is rotated by rotating mechanism. The projection data P(s, theta) from the respective measuring directions of the measuring section are obtd. in the projection data collecting part in this way. The emission intensity distribution I(x, y) of the measuring section satisfying the relation of the equation (where s: the position on an image sensor, theta: the rotating angle of the rotating mechanism indicating the measuring direction, x, y: the coordinate position on the measuring section) is calculated from the contribution rate W(s, x, y) of the emitted light predetermined according to the respective positions in the measuring section and the respective measuring directions and the resulted projection data from the respective measuring directions by using the successive approximation calculation method, by which the above-mentioned distribution is reconstituted to the two-dimensional emission intensity distribution video within the measuring section of a specimen.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is directed to the two-dimensional emission intensity distribution in one engineered cross section of a light source in combustion phenomena, various types of discharge tubes, light emission phenomena such as plasma, etc. This article relates to a method of measuring and imaging luminescence intensity distribution.

(Prior Art) In the design and development of various discharge tubes, and in the development of various technologies that utilize combustion phenomena, plasma, etc., the spatial luminescence distribution inside the light source, that is, the luminescence intensity distribution in each arbitrary cross section, is measured using a CRT display device, for example. It is desired that the images be visualized using .

Conventionally, as a method to accurately measure the emission intensity distribution at each arbitrary cross section inside the light source, a method is used in which a probe is inserted into each measurement target position inside the object such as a light source and directly measured.9 Spectroscopic analysis method, laser beam Alternatively, methods have been adopted in which combustion phenomena and plasma distribution are measured from scattering of electromagnetic waves and wavelength shifts using microwaves.

However, if the probe is directly inserted into the subject, the emission intensity distribution to be measured itself will be disturbed, making it impossible to obtain an accurate emission intensity distribution. In addition, in the spectroscopic analysis method, the obtained emission intensity distribution at each position is a value obtained by integrating components in the depth direction, and a correct emission intensity distribution cannot be obtained. Furthermore, if the method uses laser light or microwaves, the six values obtained are for each point, and it is necessary to carry out a large number of measurements to obtain the spatial distribution of emission intensity. It was difficult to adopt this method as a method for measuring distribution.

In order to eliminate these inconveniences, for example, the CT (computed tomography) method, which has made rapid progress in the field of clinical medicine in recent years, has been applied to visualize the luminescence intensity (ti), and then optical ECT ( There is a 1-symmetry CT (radial CT) method.

FIG. 7 is a diagram showing the principle of the future ECT method. 1 is the center position of a measurement section in the subject, and this measurement section has an emission intensity of I (x, y) with center position 1 as the center 0 of the xy coordinates. And this coordinate (x, y
) A single light-receiving element 2 is provided, which is a collimator that moves in a direction inclined by θ with respect to the axis. Then, since only the light from the light emitting sources existing on a straight line enters the single light receiving element 2, the light emission intensity distribution I(x,
The line integral value along the straight line of y) is determined as 7]1+J.

Therefore, projection data P (s, θ) from the θ direction can be obtained by mechanically scanning the single light receiving element 2 in a direction inclined by the angle θ. Note that S is θ
It is the position of the direction.

By measuring such projection data P (s, θ) from each direction around the Jl constant cross section of the object while changing θ, and applying the known CT The two-dimensional luminescence intensity distribution 1 (x, y) within a cross section can be visualized without contact or penetration. .

However, even if the optical ECT method shown in FIG. 7 is used, projection data P from each direction is obtained by changing θ.
To obtain (s, θ), the rotation angle (tilt angle) θ
It is necessary to fix the single light receiving element 2 and mechanically scan it in the S direction to measure the emission intensity at each position S. Therefore, the projection data P (s, θ
), it requires a lot of time and effort, and it requires a lot of time and effort to obtain the two-dimensional emission intensity distribution in each cross section of the object.
When performing the work of measuring the spatial distribution of luminescence intensity of the entire subject, there is a problem in that work efficiency is significantly reduced.

(Problem to be Solved by the Invention) As described above, according to the conventional imaging method of luminescence intensity distribution, since a single light receiving element is used, it is difficult to measure the luminescence intensity at each position in each direction. First, it is necessary to sequentially mechanically scan this single light-receiving element. Therefore, a large amount of time is required to determine the spatial luminescence intensity distribution of the entire subject as Δllj, and there is a problem in that the work efficiency for determining ΔIIJ is reduced.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, according to the imaging method of the luminescence intensity distribution of the present invention, an arbitrarily set measurement cross section of the light emitted from the object is provided. A projection data collection unit that measures a one-dimensional luminescence intensity distribution with an image sensor through a lens and double slit and outputs it as projection data, and a projection data collection unit that is placed in the same plane as the measurement cross section of the object. By rotating the projection data collection section with the rotation mechanism, the projection data collection section obtains projection data P (s, θ) from each measurement direction of the measurement cross section, and tpj From the light emission contribution rate W (s, x, y) predetermined according to the position within the constant cross-section cross section and the measurement direction and the projection data from each measurement direction obtained, the IIp1 constant cross section that satisfies the relationship of the following formula is obtained. The luminescence intensity distribution 1 (x, y) is calculated using a successive approximation calculation method and reconstructed into a two-dimensional luminescence intensity distribution image within the measurement cross section of the subject.

P (s, θ) −j'J' I (x, y) W (s, x, y) dx
dy However, S: position on the image sensor.

θ:: Rotation angle of the rotation mechanism indicating a fixed direction.

X,)': Coordinate position on the measurement surface (effect) The principle of obtaining a two-dimensional light intensity distribution in an arbitrary measurement cross section of the object using the method of this invention will be explained using FIGS. 2 to 5. explain.

The projection data collection unit and rotation mechanism are configured as shown in FIG. 2, for example. That is, a rotation mechanism 4 is disposed so as to surround the subject 3, and a projection data collection section 5 is mounted on the rotation mechanism 4. Each slit 7a forms a.

7b, lens 8. This configuration includes an image sensor 9. Therefore, only the light emitted from the arbitrarily set measurement cross section 10 shown by diagonal lines of the subject 3 is emitted from the slit 7a.
Lens 8. It is input to the image sensor 9 via the slit 7b. Therefore, the emission intensity distribution 1 (x, y) within the measurement cross section 10 is projected onto the image sensor 9 at the rotation angle θ, and the projection data P (s , θ
) is measured as

However, since the I7 lens 8 is used, as shown in FIG. Emission intensity will also be measured.

Therefore, it is not possible to obtain the two-dimensional emission intensity distribution 1 (x, y) of the xy locus plane within the relevant measurement section 10 using the conventional OCT reconstruction method shown in FIG.

Therefore, in the present invention, the concept of shift ratio is used. This contribution rate refers to the measurement cross section 10 as shown in FIG. 4(a).
It is shown by the projection data obtained at each position S on the image sensor 9 when it is assumed that the 111th light source exists only at one point [coordinates (, x, y)] 11 within.

That is, the contribution rate can be expressed as W(s, x, y). Therefore, as shown in FIG. 4(b), the point [
If there is a light source with an emission intensity distribution 1 (x, y) H at the coordinates (x, y)] 11, the projection data from that light source will be 1 (x, y)W (s, x, y) Therefore, the projection data P(srθ) as a whole is P (s, θ) = fJ' I (x, y) W (s, x, y)
dxdy...(1) Therefore, from this equation (1), M1 definite 1fIi
Emission intensity distribution within 10! (x, y), but since the contribution rate W(s, x, y) is shi r t, -VgrianL as shown in Figure 4(a), it can be easily calculated using a simple mathematical method. It is difficult to solve by processing.

Therefore, as shown in FIG. 5, the projection data P (s, θ) obtained by actual measurement and the estimated emission intensity distribution value 1
The final emission intensity distribution L (x
, y).

That is, first, the measurement cross section 10 of the object 3 is displayed on the computer.
An initial estimated emission intensity distribution value 1t(x, y) of the emission intensity distribution 1 (x, y) is created. Then, this initial emission intensity estimated distribution value Ii (x, y) and the contribution rate W (s,
x, y) and performs double integral calculation using equation (1) to obtain calculated projection data Pi(s, θ). Then, the obtained projection data Pi (S, θ) is compared with the actually determined projection data P (sr θ), and the error [P (s, θ) − Pi (s, θ) ] The six values forming the estimated quantity are defined as the contribution rate W(s, x, y)
Additively correct by adding weights. This correction is applied to projection data P (s
, θ), the reconstructed emission intensity distribution of the first iterative correction is obtained.

Then, using the corrected reconstructed emission intensity distribution as the estimated emission intensity distribution value 1i (x, y), calculational projection data Pi (s, θ) is obtained again using equation (1). Then, the error with the measured projection data [P(s, θ)−Pi
(s, θ)].

By repeatedly performing such calculations until the error falls within a predetermined range, the final emission intensity distribution I in the measurement cross section 10
(x, y) is obtained. Obtained luminescence intensity distribution! (
x, y) are displayed as a luminescence intensity distribution image on, for example, a CRT display device.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a method of visualizing a luminescence intensity distribution according to an embodiment, and the same parts as in FIG. 2 are given the same reference numerals. For example, a rotary table 4a having an inner diameter of 140.0 mm and serving as a rotating mechanism is disposed so as to surround the subject 3, which is made of a fluorescent lamp with a diameter of 31 mm and not coated with fluorescent paint. This rotary table 4a is rotated around the subject 3 by a stepping motor 4C via a belt 4b. A projection data collection unit 5 is mounted on this rotary table 4a.

This projection data collection unit 5 includes each slit 7a, 7b+lens 8. which forms a double slit on the support base 6. This configuration includes an image sensor 9.

The slit direction of each slit 7a, 7b is set within a plane perpendicular to the axis of the subject 3. Further, the lens 8 is a cylindrical lens with an arcuate cross section of H, and has, for example, a diameter of 28.5 mm and a focal length of 19.05 m. It is located at a distance of 108.5 mm from the central axis of the subject 3 made of the fluorescent lamp. In the embodiment, the image sensor 9 includes a large number of 2/3-inch C
It is composed of a line sensor in which CD elements are arranged linearly, and the distance between this image sensor 9 and the center position of the lens 8 is 28.5111. The focal point of the lens system is set approximately at the center of all assertions 10 of the subject 3.

Note that a filter is inserted between the lens 8 and the image sensor 9. By doing so, it is also possible to select the wavelength of light incident on the image sensor 9.

Therefore, only the light emitted from the 1° measurement cross section shown by diagonal lines of the subject 3 is transmitted through the slit 7a and the lens 8. It is input to the image sensor 9 via the slit 7b.

Therefore, the emission intensity distribution 1 (
x, y) are projected onto the image sensor 9 at the rotation angle θ and are measured as projection data P (s, θ) as a function of the rotation angle θ and the position S on the image sensor 9.

The video signal output from the image sensor 9 is a black and white 25
After being once imported into the frame memory 12 at 6 gradations, the projection data P (
s, θ) to the computer 13. Note that the value of the measured projection data P (s, θ) can also be directly monitored by the operator using the monitor device 14.

Computer 13 is one 1 from Frameri 12
When the projection data P (s, θ) in a fixed direction is taken in, it is transferred to the stepping motor 4 via the I10 boat 15.
C is driven to rotate the rotary table 4a and move the data collection unit 5 to the next measurement direction (rotation angle θ). Then, similar projection data P (s.

θ) measurement.

In addition, according to the method of the embodiment, the rotation angle θ of the movement in − times is
was set to 66, and a total of 60 projection data P (s, θ) were obtained from the n1 fixed direction of -circumference 60, and the time required for the measurement was about 25 seconds.

Then, each of the obtained 60 projection data P(sr
θ) using the above-mentioned successive approximation calculation method, 3
The emission intensity distribution P (x, y) of a 32×32 matrix of 21 square meters square is visualized.

The results are then displayed on the CRT display device 16.

FIG. 6 is a light emission intensity distribution characteristic diagram of each Ml constant section at each axial position every 15III1 of the fluorescent lamp 3a as the subject 3 obtained by the example method shown in FIG. The measurement wavelengths were set to 44010 and 5 using the filters described above.
There are two types: 40n1Il.

From these emission intensity distribution characteristics, we can see that strong light emission occurs unevenly near the lower electrode, that the area about 15 mm away from the electrode corresponds to a Faraday dark area and the emission intensity is small, and that the area that is more than 30+++ meters away does not emit light. It can be confirmed that the strength is a stable pillar of sunlight. It can also be understood that the state of light emission differs depending on the wavelength.

The above results are in good agreement with the characteristic light emitting behavior of general fluorescent lamps, and it has been demonstrated that this imaging method can ensure sufficient measurement accuracy for practical use.

[Effects of the Invention] As explained above, according to the method for imaging the luminescence intensity distribution of the present invention, projection data of the luminescence intensity at each position in the cross-sectional direction of the object in each measurement direction can be obtained using one image sensor. The emission intensity distribution in the measurement cross section is calculated by a sequential calculation method using the projection data obtained by instantaneous measurement and the contribution ratio.

Therefore, it is not necessary to measure the emission intensity at each position in the cross-sectional direction of the object by mechanical scanning using a single light-receiving element, so that the efficiency of measurement work can be greatly improved.

Also, of course, without contacting and invading the subject,
Since the emission intensity distribution characteristics at the pressure lFr1Ij of the object can be visualized, measurement accuracy can be improved and it can be effectively applied to the elucidation of various luminescence phenomena and the design and development of discharge tubes.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a method of visualizing a luminescence intensity distribution according to an embodiment of the present invention, FIG. 2 is a perspective view for explaining the invention in detail, and FIGS. 3 and 4 are diagrams showing the invention. FIG. 5 is a flowchart showing the process of imaging the emission intensity distribution of the present invention, and FIG.
The figure is a diagram of the emission intensity distribution of a fluorescent lamp determined using the method of the embodiment, and FIG. 7 is a schematic diagram showing the conventional method of determining n1. 3... Subject, 4... Rotating mechanism, 4a... Rotating table, 4C... Stepping motor, 5... Projection data collection unit, 7a, 7b... Slit, 8... Lens ,
9... Image sensor, 10... Measurement section, 12.
・・Frame memory, 13・・Computer, 16・
...CRT display device.

Claims (1)

[Claims] Projection data in which a one-dimensional emission intensity distribution of light emitted from a subject at an arbitrarily set measurement cross section is measured by an image sensor through a lens and a double slit and output as projection data. The projection data collection unit includes a collection unit and a rotation mechanism that rotationally moves the projection data collection unit in the same plane as the measurement cross section of the object, and the projection data collection is performed by rotating the projection data collection unit with the rotation mechanism. Projection data P(s, . A method for imaging a luminescence intensity distribution, the method comprising reconstructing a two-dimensional luminescence intensity distribution image within a measurement cross section of a subject. P(s, θ) =∫∫I(x,y)W(s,x,y)dxdyHowever, s
: position on the image sensor, θ: rotation angle of the rotation mechanism indicating the measurement direction, x, y: coordinate position on the measurement cross section