JP2007316035A - Method and apparatus for measuring the performance of fluorescent magnetic powder - Google Patents

Abstract

A method for measuring the performance of a fluorescent magnetic powder solution, which makes it possible to more accurately evaluate the performance of the fluorescent magnetic powder solution and to adjust various factors in order to improve the performance of the fluorescent magnetic powder solution. A performance measuring device is provided.
An ultraviolet irradiation means, an imaging means, an image processing means for image processing of an image taken by the imaging means, and an S / N ratio based on the image processed by the image processing means. S / N ratio calculating means 5 for calculating the S / N ratio, and the fluorescent magnetic powder to be measured is sprayed on the test body W provided with the standard rod V, and the S / N ratio is calculated from the captured image. The performance is evaluated by the / N ratio.
[Selection] Figure 1

Description

  The present invention relates to a fluorescent magnetic powder performance measuring method and performance measuring apparatus. More specifically, the present invention relates to a fluorescent magnetic powder solution performance measuring method and a performance measuring apparatus for measuring predetermined numerical values related to performance in order to evaluate the performance of the fluorescent magnetic powder solution used in the fluorescent magnetic particle flaw detection method.

  In the inspection by the fluorescent magnetic particle flaw detection method, the material to be inspected is magnetized to generate a leakage magnetic flux in the buttock, and in that state, the fluorescent magnetic powder liquid is applied to the material to be inspected. The surface wrinkles of the material to be inspected are detected by measuring

  Hereinafter, the problems pointed out regarding the performance of the fluorescent magnetic powder liquid used for the fluorescent magnetic powder flaw detection are listed.

  1) Degradation of wrinkle detection accuracy due to phosphor peeling.

  The fluorescent magnetic powder suspended in the fluorescent magnetic powder liquid is obtained by attaching a phosphor to the surface of the iron powder, and the phosphor is peeled off from the iron powder during use. As a result, only iron powder adheres to the collar portion of the material to be inspected, or the peeled phosphor adheres to a portion other than the collar, thereby reducing the accuracy of wrinkle detection.

  2) Decrease in wrinkle detection accuracy due to contamination of foreign matters such as scale and dust.

  When these problems occur, the amount of the fluorescent magnetic powder adhering to the heel portion decreases, and there is a possibility that the heel is missed or the heel is determined to have a smaller area than the actual size.

  3) Reduction in soot detection accuracy due to a decrease in the amount of effective fluorescent magnetic powder in the liquid.

  In the fluorescent magnetic powder liquid, normal fluorescent magnetic powder, which is an effective component for fluorescent magnetic powder flaw detection, and ineffective components such as a single phosphor and iron powder are mixed. Adsorbed and taken out of the fluorescent magnetic powder. As a result, the concentration of components that are not effective increases, and accurate fluorescent magnetic particle inspection cannot be performed.

  In other words, simply measuring the concentration of the fluorescent magnetic powder liquid cannot sufficiently evaluate the performance of the fluorescent magnetic powder liquid due to the effects of components that are not effective for fluorescent magnetic powder flaw detection such as a single phosphor and iron powder alone. was there.

  For this reason, as described in Patent Document 1 below, for example, a fluorescent magnetic powder is sprayed on an electromagnet, the fluorescent magnetic powder is adsorbed on the electromagnet, and excitation light from an excitation light source is irradiated on the electromagnet. There has been proposed a performance measuring apparatus that measures the fluorescence luminance of magnetic powder with a photoelectric converter and evaluates the performance of the fluorescent magnetic powder liquid based on the ratio between the measured fluorescence luminance and the intensity of excitation light (also the following patent) Reference 2).

  As described above, the performance measuring apparatus according to the proposal measures the luminance value of the fluorescent magnetic powder in the fluorescent magnetic powder liquid using the photoelectric converter, thereby measuring the concentration of the active ingredient in the fluorescent magnetic powder liquid. Based on this, the performance of the fluorescent magnetic powder liquid represented by the concentration of the active ingredient is measured.

However, the properties of the fluorescent magnetic powder liquid, that is, the properties related to the flaw detection accuracy of the fluorescent magnetic powder liquid, according to the study by the applicants, as described later, are not only the concentration of the active ingredient in the liquid, but also various factors. Therefore, the performance measuring apparatus according to the proposal has a problem that the performance of the fluorescent magnetic powder liquid cannot be accurately evaluated.
JP-A-8-94582 JP 59-26897 A

  The present invention has been made in view of the problems of the prior art, and can adjust the various factors to improve the performance of the fluorescent magnetic powder so that the performance of the fluorescent magnetic powder can be more accurately evaluated. It is an object of the present invention to provide a fluorescent magnetic powder performance measuring method and performance measuring apparatus that can be used.

  The fluorescent magnetic powder performance measuring method of the present invention is a fluorescent magnetic powder liquid performance measuring method used in the fluorescent magnetic particle flaw detection method, and a procedure for spraying the fluorescent magnetic powder liquid to be measured on a test specimen provided with a standard rod , Procedure for irradiating a test specimen with a fluorescent magnetic powder solution irradiated with ultraviolet light, imaging a test specimen irradiated with ultraviolet light, scanning the captured image in a perpendicular direction, and creating a luminance distribution of the scanned image And a procedure for calculating the S / N ratio from the obtained luminance distribution, and a procedure for measuring the performance of the fluorescent magnetic powder liquid based on the obtained S / N ratio.

  In the method for measuring the performance of the fluorescent magnetic powder liquid of the present invention, it is preferable that a procedure for measuring the continuity of the luminance distribution in the heel direction is added.

  On the other hand, the fluorescent magnetic powder performance measuring apparatus of the present invention is a fluorescent magnetic powder performance measuring apparatus used in the fluorescent magnetic particle flaw detection method, and includes an ultraviolet irradiation means, an imaging means, and an image captured by the imaging means. An image processing means for performing image processing and an S / N ratio calculating means for calculating an S / N ratio based on an image processed by the image processing means are provided.

  In the apparatus for measuring the performance of a fluorescent magnetic powder according to the present invention, it is preferable to include a connection continuity measuring means for measuring the continuity of the luminance distribution in the heel direction.

  Since this invention is comprised as mentioned above, the outstanding effect that the performance of a fluorescent magnetic powder liquid can be evaluated appropriately is acquired.

  Hereinafter, although the present invention is explained based on an embodiment, referring to an accompanying drawing, the present invention is not limited only to this embodiment.

  In FIG. 1, the schematic of the performance measuring apparatus applied to the performance measuring method of the fluorescent magnetic powder liquid of this invention is shown.

  The performance measuring device U is an ultraviolet light that irradiates ultraviolet rays onto a test material W having a predetermined area (hereinafter referred to as an inspection area) S with a ridge (for example, a sensor having a length of 20 mm and a depth of 0.3 mm) V (Ultraviolet illumination means) 1, a CCD camera (imaging means) 2 for imaging the inspection region S of the test material W irradiated with ultraviolet rays by the ultraviolet light 1, and an optical lens 2 a of the CCD camera 2 are provided in front of An optical filter 3 for transmitting only an ultraviolet ray having a predetermined wavelength (about 500 nm to 600 nm) to be imaged by the CCD camera 2, and an image processing unit (image for performing predetermined image processing on the image captured by the CCD camera 2) Processing means) 4 and the luminance of the skin V corresponding portion of the test material W (hereinafter referred to as S value) and the luminance of the other skin portion (hereinafter referred to as N) for each pixel of the image processed by the image processing unit 4. S / N ratio (S / N ratio calculation means) 5 for calculating the S / N ratio (detection sensitivity difference between the heel and skin (background)), and the fluorescent magnetic powder pattern A connection continuity measuring unit (connection continuity measuring means) 6 that measures the connection continuity of the image, a graphing unit 7 that graphs the luminance of each pixel of the image processed by the image processing unit 4, and an S / N The display unit 8 that displays the calculation result of the ratio calculation unit 5, the measurement result of the connection continuity measurement unit 6, and the graph generated by the graphing unit 7 is provided as a main component.

  Here, the image processing unit 4, the S / N ratio calculation unit 5, the connection continuity measurement unit 6, the graphing unit (graphing unit) 7, and the display unit (display unit) 8 are configured by a computer 10.

  The test material W is made of the same material as the material to be inspected in the fluorescent magnetic particle inspection method, that is, a plate material made of a ferromagnetic material such as steel. Further, a fluorescent magnetic powder for performance measurement is applied to the test material W by a conventional method.

  The CCD camera 2 captures the inspection area S of the test material W to which the fluorescent magnetic powder for performance measurement is applied with a predetermined resolution. For example, the inspection area S is imaged at a resolution of 1024 × 1024 pixels.

  FIG. 2 shows an example of an image of the inspection area S imaged by the CCD camera 2 and subjected to image processing by the image processing unit 4.

  As shown in FIG. 2, each pixel in the inspection region S has an orthogonal coordinate (x, x, x) (X, 1024 pixels) substantially perpendicular to 疵 V and a Y axis (1024 pixels) substantially parallel to 疵 V. The position is indicated by y).

  Further, as shown in FIG. 3, each pixel in the inspection region S is grouped into each line parallel to the X axis, and the luminance of each pixel is shown as a height (Z coordinate) from the XY plane. It is supposed to be.

  FIG. 4 shows a graph in which the luminance value of each pixel is extracted by XZ coordinates by taking out one line in FIG. In FIG. 4, the pixel a is a pixel corresponding to 疵 V.

  Next, a calculation method in which the S / N ratio calculation unit calculates the S / N ratio will be described with reference to FIG.

  As shown in FIG. 5, the S / N ratio calculation unit 5 compares the luminance of each pixel with a predetermined threshold value (hereinafter referred to as wrinkle determination threshold value) SH in each line of the captured image of the inspection region S. A pixel whose luminance is larger than the wrinkle determination threshold SH (pixel D4 in the illustrated example) is extracted as a wrinkle, while a pixel whose luminance is smaller than the wrinkle determination threshold SH (the pixels D1, D2, D3, D5 in the illustrated example, D6, D7, D8) are extracted as skin parts, and the maximum value of luminance in each pixel (D4) of the extracted heel part is set as an S value, while each pixel (D1, D2, D3, D5, The average value of the brightness of D6, D7, D8) is calculated to obtain the N value.

  The S / N ratio calculation unit 5 calculates the S / N ratio using the S value and the N value calculated in this way. The S / N ratio calculated by the S / N ratio calculation unit 5 is displayed on the display unit 7 as a numerical value related to the performance of the fluorescent magnetic powder liquid.

  In addition, the S / N ratio calculation unit 5 repeats the above-described procedure for all lines of the captured image of the inspection region S so that the connection continuity measurement unit 6 can measure the connection continuity of the fluorescent magnetic powder pattern. The S / N ratio is calculated. In this way, the S / N ratio of the entire image in the inspection area S is calculated.

  The connection continuity measuring unit 6 measures the connection continuity of the fluorescent magnetic powder pattern as follows.

  That is, if the field of view of 1024 pixels in the Y direction is 250 mm, the length per pixel is 0.25 mm. Therefore, for example, if the S value exists continuously for 4 lines, that is, 1 mm (0.25 × 4) or more, it is assumed that there is continuity, and conversely if it is less than that, continuity is measured. . In other words, if there is an S value at a predetermined number of lines or more in the Y direction, continuity is measured as having continuity.

  The connection continuity of the fluorescent magnetic powder pattern measured by the connection continuity measuring unit 6 is related to the stability of the adhesion of the fluorescent magnetic powder to the heel (a property related to the luminance variation of the heel), the dispersion action and the permeation action of the magnetic powder liquid. The display unit 8 displays numerical values related to the performance of the fluorescent magnetic powder liquid.

  The graphing unit 7 determines the concentration of active ingredients in the fluorescent magnetic powder liquid (such as iron powder that does not peel off and adheres normally) and other factors that affect the performance of the fluorescent magnetic powder liquid as described later. The luminance value of each line is graphed so that the change in the S / N ratio when adjusting the can be visually recognized.

  As described above, in the embodiment apparatus, the pixels of the captured image of the inspection region S are grouped into lines substantially perpendicular to 疵 V, and each grouped line is scanned and 疵 for each line. The S / N ratio, which is the ratio of the luminance (S value) of the skin part and the luminance (N value) of the skin part, is calculated, and the continuity of the fluorescent magnetic powder pattern is connected based on the S / N ratio calculated for all lines. And the calculated S / N ratio and the measured connection continuity are output as numerical values related to the performance of the fluorescent magnetic powder. This makes it possible to more accurately evaluate the performance of the fluorescent magnetic powder.

  That is, according to the research by the applicants, as described later, the performance of the fluorescent magnetic powder liquid is not only the concentration of the normal fluorescent magnetic powder (active ingredient concentration) from which the phosphor is not peeled, but also other factors such as Although not known, it varies depending on the content of the surfactant. However, it is not possible to know the influence of the surfactant content on the performance of the fluorescent magnetic powder simply by measuring the luminance of the fluorescent magnetic powder as in Patent Document 1.

  In this regard, in the embodiment device, the S / N ratio is calculated as a numerical value for evaluating the performance of the fluorescent magnetic powder liquid, and therefore the influence of the surfactant content and the influence of other factors are included. It becomes possible to accurately evaluate the performance of the fluorescent magnetic powder.

  In addition, by measuring the connection continuity of the fluorescent magnetic powder pattern, it becomes possible to know the stability of the adhesion of the fluorescent magnetic powder to the buttocks, the dispersion and penetration of the magnetic powder, and the performance of the fluorescent magnetic powder. Can be more accurately evaluated.

  6 and 7, when the fluorescent magnetic powder concentration (active ingredient concentration) in the fluorescent magnetic powder liquid is made constant and other factors affecting the performance of the fluorescent magnetic powder liquid, here the content of the surfactant is adjusted. Examples are shown together with comparative examples.

  In FIG. 6, the comparative example shows the S value, N value and S / N ratio when the content (weight percentage) of the surfactant added to the fluorescent magnetic powder liquid is 0.5%. At this time, the S / N ratio was 1.7.

  Example 1 shows the S value, N value, and S / N ratio when the surfactant content is 1.0%, and the S / N ratio was 2.5 at this time. .

  Example 2 shows the S value, N value, and S / N ratio when the surfactant content is 1.5%. At this time, the S / N ratio was 2.8. .

  FIG. 7 shows a diagram corresponding to FIG. 4 of the comparative example, the first embodiment, and the second embodiment.

  From the above results, it is understood that the S / N ratio increases as the content ratio increases in the range of 0 to 1.5% of the surfactant content.

  Therefore, by measuring the S / N ratio as a numerical value related to the performance of the fluorescent magnetic powder, the optimum surfactant content can be known.

  Further, for example, it is possible to know the optimum concentration of the fluorescent magnetic powder by adjusting the content of the surfactant, adjusting the concentration of the fluorescent magnetic powder, and measuring the performance of the fluorescent magnetic powder with the embodiment device.

  The present invention can be applied when evaluating the performance of a fluorescent magnetic powder.

It is the schematic of the performance measuring apparatus of the fluorescent magnetic powder liquid which concerns on one Embodiment of this invention. It is a schematic diagram which shows an example of the captured image of a CCD camera. It is the graph which graphed the brightness | luminance of each pixel of the captured image of FIG. FIG. 4 is a graph obtained by extracting one line from the graph of FIG. 3. FIG. 5 is a reference diagram of a calculation method for calculating the S / N ratio of one line in FIG. 4. It is a graph which shows the Example and the comparative example which measured the performance of the fluorescent magnetic powder liquid with embodiment apparatus. FIG. 7 is a diagram corresponding to FIG. 4 of the example of FIG. 6 and the comparative example, in which (a) shows a comparative example, (b) shows Example 1, and (c) shows Example 2. FIG.

Explanation of symbols

U performance measuring apparatus 1 ultraviolet light 2 CCD camera 4 image processing unit 5 S / N ratio calculation unit 6 connection continuity measurement unit 7 graphing unit 8 display unit 10 computer

Claims (4)

A method for measuring the performance of a fluorescent magnetic powder liquid used in a fluorescent magnetic particle flaw detection method,
A procedure for spraying the fluorescent magnetic powder to be measured on a test specimen provided with a standard rod,
The procedure of irradiating the test body sprayed with the fluorescent magnetic powder liquid with ultraviolet rays,
A procedure for imaging a specimen irradiated with ultraviolet rays;
A procedure for scanning a captured image in a vertical direction;
A procedure for creating a luminance distribution of a scanned image;
A procedure for calculating the S / N ratio from the obtained luminance distribution;
And a procedure for measuring the performance of the fluorescent magnetic powder based on the obtained S / N ratio.   The method for measuring the performance of a fluorescent magnetic powder liquid according to claim 1, further comprising a step of measuring the continuity of the luminance distribution in the eyelid direction. An apparatus for measuring the performance of a fluorescent magnetic powder liquid used in a fluorescent magnetic particle flaw detection method,
Ultraviolet irradiation means, imaging means, image processing means for image processing an image taken by the imaging means, and S / N ratio for calculating an S / N ratio based on the image processed by the image processing means An apparatus for measuring the performance of a fluorescent magnetic powder liquid, comprising: an arithmetic means.   The apparatus for measuring the performance of a fluorescent magnetic powder liquid according to claim 3, further comprising a connection continuity measuring means for measuring the continuity of the luminance distribution in the heel direction.

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