JP4618502B2 - Fluorescence flaw detector and fluorescent flaw detection method - Google Patents

Description

  The present invention is capable of inspecting the entire surface of a subject (inspection object) having a complicated shape by preventing the generation of blind spots, detecting fine scratches with a high S / N ratio, and detecting the detected scratches. The present invention relates to a fluorescence flaw detection apparatus and a fluorescence flaw detection method for detecting the size of the object and the position on the subject.

  As a nondestructive inspection method for metal materials and ceramics, a fluorescence penetrant test is known. In the fluorescence penetrant flaw detection test, the fine scratches (or wrinkles) present on the surface of the specimen are infiltrated with the fluorescent agent using the capillary phenomenon, and the fluorescent agent is irradiated with near ultraviolet rays to observe the fluorescent agent. Inspects for defects such as scratches with the naked eye.

Further, as a nondestructive inspection method similar to this, a fluorescent magnetic particle flaw detection test is known. The fluorescent magnetic particle flaw detection test magnetizes a ferromagnetic specimen, applies the fluorescent magnetic powder to the surface, irradiates the fluorescent magnetic powder adsorbed on the scratched part such as a crack, and emits the fluorescent magnetic powder by emitting near-ultraviolet rays. And inspecting the wounds etc. with the naked eye.
Hereinafter, both the fluorescent penetrant test and the fluorescent magnetic particle test are collectively referred to as a “fluorescent test”.

The above-described fluorescent flaw detection test generally includes the steps of (1) penetration treatment, (2) cleaning treatment, (3) development treatment, and (4) inspection. However, since the inspection process is a visual inspection with the naked eye, there is a problem that it is easily influenced by experience and takes time and effort. Therefore, means for extracting defects using image processing has been proposed in the fluorescence flaw detection test (for example, Patent Documents 1 to 4).
Further, Patent Document 5 is disclosed as means for continuously performing permeation processing, cleaning processing, and development processing other than the inspection process.

  The method of Patent Document 1 includes the steps of selecting at least one target specimen, pre-treating the specimen using an indicator that enables the display of surface defects based on the selected analysis method, Exposing the target specimen under appropriate illumination suitable for the selected indicator; processing the image to remove artifacts to determine detection sensitivity and background noise caused by the selected analytical method; Determining effective parameters, and determining parameter values that maximize detection sensitivity and minimize background noise for each effective parameter.

  The method of Patent Document 2 uses the apparatus shown in FIG. 6 to attach fluorescent magnetic powder to the surface of a magnetized steel piece, and irradiate the fluorescent magnetic powder with excitation light to image the emitted fluorescence to detect flaws. In this method, a plurality of luminance reference values that differ depending on the type of eyelids and a threshold value for limiting the range of the feature amount used for the type of discrimination are set in advance, and the imaging signal is determined based on each criterion value. A plurality of binarized images are created, a predetermined feature amount is calculated from the binarized image, a predetermined calculation is performed based on the feature amount and the preset threshold value, and this calculation is performed. Based on the result, the species is discriminated.

  The apparatus of Patent Document 3 includes an irradiating unit that irradiates ultraviolet rays onto the surface of a material to be inspected to which fluorescent magnetic powder is attached, an imaging apparatus that images the surface and outputs an image signal, and the signal strength of the image signal is damaged. In the fluorescent magnetic powder type automatic flaw detection apparatus having a scratch judgment means for judging the presence or absence of a scratch on the surface by comparing judgment thresholds, the ultraviolet light incident conditions and the fluorescent magnetic powder emitted from each surface portion of the inspection object A storage means for storing different scratch determination thresholds for each part of the surface that is determined in advance so that the presence or absence of a scratch can be determined under substantially the same condition regardless of the difference in the incidence condition of light on the imaging device; The judging means judges the presence or absence of a flaw by comparing the flaw judgment threshold with the signal intensity of the image signal of the corresponding part.

  As shown in the schematic diagram of FIG. 7, the apparatus of Patent Document 4 includes magnetizers 51 and 52 that magnetize a surface layer portion of a steel material 53, an injection nozzle 55 that sprays magnetic powder liquid on the surface of the steel material, and a steel material to be inspected. In a surface wrinkle automatic inspection apparatus constituted by a black light 57 that illuminates a surface, an ITV camera 58 that images a surface to be inspected, and an image processing device 59 that performs image processing on an output signal of the ITV camera to determine the presence or absence of wrinkles A light source 63 that irradiates visible light intermittently on the surface to be inspected of the steel 53, and a control device 64 that synchronizes the light emission of the light source and the image capture timing of the ITV camera, and is illuminated with a black light 57. The surface flaws are inspected from the image when the light is applied and the image when the illumination of the light source unit 63 is added.

  As shown in the schematic diagram of FIG. 8, the apparatus of Patent Document 5 includes a horizontal circulation chain conveyor 62 that suspends a plurality of workpieces 61 at a constant pitch P and intermittently circulates horizontally, and a lower part of the horizontal circulation chain conveyor. And a plurality of processing devices 64 for performing predetermined processing on the workpiece, and an elevating device 66 for moving the processing device up and down, stopping the operation of each processing device and lowering each processing device. The horizontal circulation chain conveyor is moved by a constant pitch P, the horizontal circulation chain conveyor is stopped, and each processing apparatus is raised to perform each processing.

Japanese Patent No. 3095958, “Method and apparatus for automatically characterizing, optimizing and inspecting analysis method by penetrant flaw detection” Japanese Patent No. 3440569, “Magnetic particle flaw detection method and apparatus” Japanese Patent Application Laid-Open No. 06-201656, “Fluorescent Magnetic Powder Automatic Flaw Detector” Japanese Patent Laid-Open No. 10-282063, “Surface Flaw Automatic Inspection Device” Japanese Patent Application Laid-Open No. 2003-98110, “Continuous Penetration Flaw Detector”

  For example, when a turbine blade or a compressor blade for an aircraft is used as a subject, the inspection area is, for example, a maximum of about 100 mm × 100 mm, and the scratch to be inspected is, for example, about 0.25 mm or more in the longitudinal direction. Note that the inspection area and the size of the flaw are merely examples, and a flaw larger than or smaller than that may be targeted.

  In a fluorescent flaw detection test, when such an object is visually inspected with the naked eye, conventionally, an inspection time of about 2 minutes or more is required for each object even in the above-described inspection process alone. Therefore, the inspection efficiency is low, and there is a problem that it is impossible to inspect all the products in accordance with mass production.

Further, when trying to automate this inspection process using image processing, since fluorescence emitted from the surface of the subject is weak, it is necessary to take an image while removing visible light other than fluorescence as much as possible. That is, imaging is performed by irradiating the subject with ultraviolet light in a dark room where no external light enters. In such an environment where visible light is removed, the fluorescent part can be clearly imaged, but it is difficult to image the shape of the subject clearly. For this reason, it is difficult to determine where a defective portion such as a flaw that emits fluorescence is located on the subject.
In addition, if illumination using visible light is used to simultaneously photograph the shape of the subject, there is a problem that it is difficult or impossible to detect fine scratches.

  Furthermore, when the subject is transported to the examination region using an automatic transport device or the like, the fluorescent agent may adhere to other than the subject. In such a case, fluorescence in a region other than the subject (background portion or non-inspection region) is detected on the photographed image, and the S / N ratio is lowered, making it difficult to detect fine scratches.

  Further, when the subject has a complicated shape such as a turbine blade, a defect may be overlooked due to the generation of blind spots. In addition, the subject having such a complicated shape has a problem that the exact dimension of the defect cannot be measured.

  The present invention has been developed to solve the above-described problems. That is, the object of the present invention is to allow the entire surface of a subject (inspection object) having a complicated shape to be inspected in a short time while preventing the generation of blind spots. ) And a fluorescence flaw detector capable of easily detecting a fine flaw of a subject with a high S / N ratio without being influenced by the fluorescence from the light source, and easily identifying the detected flaw size and position on the subject. It is to provide a flaw detection method.

According to the present invention, a swiveling device capable of holding a subject having a fluorescent agent or fluorescent magnetic powder permeated or adsorbed on a surface at a predetermined examination position and capable of swiveling around a predetermined axis;
A darkroom apparatus that surrounds the subject at the examination position and maintains the inside under low illuminance capable of photographing fine fluorescence;
A black light that irradiates the subject at the inspection position with near ultraviolet rays for fluorescence testing;
A white strobe for irradiating the subject at the examination position with visible light;
A long-pass filter that cuts off the near-ultraviolet light and passes fluorescence and visible light;
A plurality of imaging cameras for imaging the subject at the examination position through the long pass filter while shifting the time from a plurality of positions, and acquiring a fluorescence still image at the time of near ultraviolet irradiation and a visible still image at the time of visible light irradiation,
An image processing device for displaying a plurality of superimposed images by superimposing the plurality of fluorescent still images and a plurality of visible still images ,
The image processing device identifies an examination region of a subject from a plurality of visible still images by three-dimensional position measurement,
A fluorescence flaw detector is provided, wherein the fluorescent still image is subjected to high-intensity region extraction processing using morphology processing to identify a fluorescent portion and calculate the position and size of the fluorescent portion .

  According to a preferred embodiment of the present invention, the image processing device specifies an examination region of a subject from a plurality of visible still images by three-dimensional position measurement, and erases an image other than the examination region from the plurality of fluorescent still images. To do.

Further, according to the present invention, a stationary step of allowing a subject having permeated or adsorbed a fluorescent agent or fluorescent magnetic powder to a surface to be placed at a predetermined examination position;
Irradiating near-ultraviolet rays for fluorescent flaw detection to a subject at an examination position in a dark room, photographing each subject from a plurality of positions through a long pass filter, and obtaining a plurality of fluorescence still images, and
Shifting the step and time, irradiating the subject at the examination position with visible light, photographing each subject through a long pass filter from the plurality of positions, and obtaining a plurality of visible still images,
An image processing step of displaying a plurality of superimposed images by superimposing the plurality of fluorescent still images and a plurality of visible still images respectively by image processing;
A turning step for turning the subject around a predetermined axis ,
Identify the examination area of the subject from multiple visible still images by measuring the three-dimensional position,
A fluorescence flaw detection method is provided, wherein the fluorescent still image is subjected to high-intensity region extraction processing using morphology processing to identify a fluorescent portion and calculate the position and size of the fluorescent portion .

  According to a preferred embodiment of the present invention, an examination region of a subject is specified from a plurality of visible still images by three-dimensional position measurement, and images other than the examination region are erased from the plurality of fluorescent still images.

  According to the apparatus and method of the present invention described above, a subject is swung at a predetermined examination position, a plurality of fluorescent still images and a plurality of visible still images are photographed from a plurality of positions at different times in a dark room, Fluorescent still images and multiple visible still images are superimposed on each other by image processing to display multiple superimposed images, so that the entire surface of the subject can be easily detected in a short time by repeating swiveling, imaging, and image display Can be inspected.

  Moreover, even if the subject (inspection object) has a complicated shape, the entire surface is inspected by turning, so that the generation of blind spots can be prevented, and the entire inspection object can be inspected.

  Also, in the darkroom, the subject swung at the examination position is irradiated with near ultraviolet rays for fluorescent flaw detection, and the subject is photographed through a long-pass filter to obtain a fluorescence still image. Can be easily detected with a high S / N ratio.

  Furthermore, by specifying the examination region of the subject from the plurality of visible still images and erasing the image other than the examination region from the plurality of fluorescent still images, the region from the region other than the subject (background portion or non-examination region) Since it is possible to eliminate the influence of fluorescence, fine scratches on the subject can be easily detected with a higher S / N ratio.

  Further, the fluorescent still image is subjected to high-intensity region extraction processing centered on morphology processing to identify the fluorescent portion, and the position and size of the fluorescent portion are calculated. Easy to identify.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

FIG. 1 is a schematic diagram of moving blades (A) and vanes (B) that are subjects, and in this example, the moving blades and vanes of an aircraft compressor are shown.
Aircraft compressors use about 10 types of moving blades and vanes, each having a different size and shape. In addition, the places requiring the fluorescent flaw detection are usually the back side and the ventral side of the tip of the wing, but are not limited to this, and other parts may be inspected.
The subject of the present invention is not limited to the aircraft parts as described above, and can be any subject such as an automobile part that requires a fluorescent flaw detection test.

  Hereinafter, a case where the inspection area of the subject 1 of the present invention is about 100 mm × 100 mm at the maximum and a wound having a longitudinal direction of about 0.25 mm or more is to be inspected will be described. In addition, this inspection area | region and the magnitude | size of a damage | wound are illustrations, It can apply similarly to the area | region beyond it, or a wound below it.

  FIG. 2 is an overall configuration diagram of a fluorescence flaw detector according to the present invention. As shown in this figure, the fluorescence flaw detector 10 of the present invention includes a swivel device 11, a transport device 12, a darkroom device 14, a black light 16, a white strobe 18, a long pass filter 20, a photographing camera 22, and an image processing device 24. .

  The subject 1 is in a state in which the permeation process, the cleaning process, and the development process described above are performed in the previous process (not shown), and the fluorescent agent or the fluorescent magnetic powder is permeated or adsorbed on the surface. The fluorescent agent is a fluorescent agent for fluorescent penetrant testing, and the fluorescent magnetic powder is fluorescent magnetic powder for fluorescent magnetic particle testing. Therefore, the present invention can be applied to the fluorescence penetration test and the fluorescent magnetic particle test.

The swivel device 11 is a device that holds a part of the subject 1 having a fluorescent agent or fluorescent magnetic powder permeated or adsorbed on the surface thereof and is capable of swiveling around a predetermined axis. For example, when the subject 1 is a moving blade of a turbine or a compressor and the inspection region is a blade portion, it is preferable to hold the fixed portion of the moving blade that is not the inspection region and turn around the vertical axis Z. The turning device 11 can numerically control the turning angle, and outputs the turning position.
Note that this configuration is not essential, and it may be swiveled around a horizontal axis or other axes, and may be arbitrarily turned without performing numerical control (for example, 180 degrees, 90 degrees, 60 degrees, 30 degrees, etc.) It may be configured to set and stop.

The transport device 12 is, for example, a belt conveyor or a roller conveyor, and loads and unloads the subject 1 in which the fluorescent agent is permeated to the surface to a predetermined inspection position while being held by the turning device 11. The transport device 12 includes a position detection sensor 13 that detects a predetermined examination position, and temporarily stops the subject 1 at the examination position. The pause time is a time required for turning and photographing described later.
In the present invention, the transport device 12 is not essential, and the subject 1 may be moved to a predetermined examination position by hand and allowed to stand.

Since the fluorescent light 4 does not emit so strong light, a certain amount of exposure time (for example, 1/30 second or more) is required for photographing. When the exposure time is 1/30 seconds and the resolution is 0.10 mm / pixel, the conveyance or turning speed is 3.0 mm / second or less, that is, to stop the blurring of the image of the subject 1 within 1 pixel. It needs to be in a state (0.10 mm / pixel ÷ 1/30 seconds).
Therefore, in order to capture two high-accuracy still images, for example, it is preferable to stop completely for about 0.5 seconds. However, complete stop is not essential, and movement may be performed at a low speed (for example, several mm / s) as long as a highly accurate still image can be taken.
Further, the exposure time may be shortened by means such as increasing the sensitivity of the CCD, increasing the fluorescence intensity, or increasing the target scratch, and the conveyance or turning may be performed continuously.

The inspection position is located on, for example, a belt conveyor or a roller conveyor, and has an image photographing area of about 1 m square, and this area can be darkened.
In addition, as a result of the fluorescence flaw inspection according to the present invention, the subject 1 determined to have a defect candidate is preferably transported to another line (not shown) and subjected to a more detailed inspection such as a visual inspection. .

The dark room device 14 surrounds the subject 1 at the examination position, and maintains the inside under a low illuminance at which fine fluorescence can be imaged. The dark room device 14 may be a flexible dark curtain covered with a light shielding cloth or a rigid dark box surrounded by a light shielding plate.
In addition, a slit, an opening / closing door, and the like are provided so that the subject 1 can be carried into and out of the dark room apparatus 14, and the interior is maintained at a low illuminance that allows photographing inside the photographing camera 22. The low illuminance that can be photographed should be as dark as possible so that the weak fluorescence 4 can be detected.

The black light 16 irradiates the subject 1 stopped at the inspection position with near ultraviolet rays 2 for fluorescent flaw detection. The black light 16 is an ultraviolet irradiation device that emits near ultraviolet rays 2 having a wavelength of 315 to 400 nm.
The black light 16 preferably radiates near ultraviolet rays 2 continuously, but may radiate only during photographing. In this example, two are provided on the left and right to prevent the shadow of the subject 1, but one or three or more lamps may be used.
In addition, when the exposure time is shortened and the conveyance or turning is continuously performed, it is preferable to set the irradiation time to an extremely short time (1/1000 second or less) as in the case of a normal stroboscope. .

  When near ultraviolet rays 2 are emitted to the fluorescent agent, fluorescence 4 is emitted. The wavelength of the fluorescence 4 varies depending on the characteristics of the fluorescent agent and external conditions (such as cleaning solution conditions and changes with time), but the peak is between 500 and 550 nm.

The white strobe 18 irradiates the subject 1 stopped at the examination position with the visible light 3. The white stroboscope 18 is a stroboscope for normal photography and preferably has an irradiation time of an extremely short time (1/1000 second or less).
In this example, two white strobes 18 are provided on the left and right sides in order to prevent the shadow of the subject 1, but one or three or more may be used.

The long pass filter 20 is an optical filter that cuts near ultraviolet rays 2 having a wavelength of about 450 to 500 nm or less and passes fluorescence 4 and visible light 3.
In a normal fluorescence inspection test, a bandpass filter that transmits only a specific wavelength is used as an ultraviolet filter. However, in the present invention, it is necessary to capture an image (visible still image) that allows the external shape of a component to be determined when using strobe illumination. Therefore, in the present invention, the fluorescent region is clearly photographed using an optical filter that does not allow the reflected light of the black light 16 to pass.

At least one photographing camera 22 is used. In this example, two photographing cameras 22 are used with an interval in a direction perpendicular to the axis (horizontal direction in this example) across the turning axis (vertical axis in this example) of the turning device 11. Each photographing camera 22 photographs the subject 1 stopped at the examination position through the long pass filter 20 from the same position, strobe ON and strobe OFF, while shifting the time, and the fluorescence still image 5 at the time of near-ultraviolet irradiation. And a visible still image 6 at the time of visible light irradiation are acquired. Therefore, a plurality of fluorescent still images 5 and a plurality of visible still images 6 corresponding to the strobe OFF and the strobe ON captured from a plurality of positions are acquired.
In this example, two imaging cameras 22 are provided on one side of the transfer device 12, but four or more imaging cameras 22 are provided on both sides of the transfer device 12 so that both surfaces of the subject 1 are inspected simultaneously. It may be.
Further, the subject 1 may be photographed with two cameras at a time from three or more sides.

The field of view of each imaging camera 22 is set to about 100 mm on a side according to the examination area of the subject 1. In addition, it is necessary to extract a very small fluorescent region having a length of 0.25 mm with respect to a viewing angle of 100 mm.
For example, in order to obtain 0.10 mm / pixel at the position of the observation object, the number of effective pixels of the CCD needs to be 1000 × 1000 pixels or more (100 mm ÷ 0.1 mm / pixel = 1000 pixels).

  For this reason, a digital video camera having a CCD effective pixel number of 1000 × 1000 pixels or more is used instead of an analog video camera that outputs video signals (480 horizontal signal lines).

  In order to capture an image with a clear fluorescent region, it is desirable that the aperture is reduced to increase the depth of field and the exposure time is increased to receive the fluorescence longer. However, in an actual inspection line, photographing time = exposure time is limited in consideration of the transport system. Therefore, it is preferable to use a camera and a lens that can change the aperture and the exposure time so that the aperture and the exposure time can be adjusted according to the operating conditions.

  When the lens has a viewing angle of 100 mm and the camera is separated from the component by 300 mm or more so that the shadow of the camera itself is not reflected, the focal length of the lens may be 20 mm or more. Therefore, it is preferable to use a lens having a focal length of about 20 mm to 50 mm.

The image processing device 24 displays a plurality of superimposed images 7 by superimposing a plurality of fluorescent still images 5 and a plurality of visible still images 6. The image processing device 24 may be a computer including a central processing unit (CPU), a storage device 25, an input / output device (for example, a keyboard, an image display device 26), and a communication control device 27.
The image processing device 24 three-dimensionally specifies the examination region of the subject 1 from the plurality of visible still images 6 by three-dimensional position measurement, and erases images other than the examination regions from the plurality of fluorescent still images 6.
Further, this image processing device 24 identifies the fluorescent part by extracting the fluorescent still image 5 with a high luminance area centered on the morphology process, and calculates the position and size of the fluorescent part by measuring the three-dimensional position of the fluorescent part. It is supposed to be.
Note that the present invention is not limited to the above-described three-dimensional position measurement method by stereo viewing using a plurality of still images, and other three-dimensional position measurement methods may be used. For example, the object shape of the examination area stored in advance may be rotated as a template image, and the examination area on the visible still image 8 that is similar to the template image may be specified by pattern matching.

  FIG. 3 is an overall flow diagram of the fluorescence flaw detection method according to the present invention. As shown in this figure, the fluorescence flaw detection method of the present invention has a stationary step S1, a fluorescent still image photographing step S2, a visible still image photographing step S3, an image processing step S4, a turning step S5, and an evaluation step S6.

  In the stationary step S1, the subject 1 in which a fluorescent agent or fluorescent magnetic powder has permeated or adsorbed on the surface is left at a predetermined examination position.

In the fluorescence still image photographing step S2, the subject 1 stopped at the examination position is irradiated with near ultraviolet rays 2 for fluorescent flaw detection in the dark room, and the subject 1 is photographed from a plurality of positions through the long pass filter 20, respectively. A fluorescent still image 5 is acquired.
During this step, the white strobe 18 remains off (extinguishes).

In the visible still image capturing step S3, the time is shifted from that of the fluorescent still image capturing step S2, the visible light 3 is irradiated to the subject 1 stopped at the examination position, and the long pass filter is applied from the same plurality of positions as in the fluorescent still image capturing step S2. The subject 1 is photographed through 20 to obtain a plurality of visible still images 6.
During this step, the black light 16 may remain on (turned on) or may be turned off (off).

  In the image processing step S4, a plurality of superimposed images 7 are displayed by superimposing a plurality of fluorescent still images 5 and a plurality of visible still images 6 by image processing.

  The image processing step S4 includes steps of a high brightness area extraction process S41, a three-dimensional position measurement S42, an inspection area specification S43, a superimposed image display S44, an image erasing S45 other than the inspection area, and a fluorescent part size calculation S46. Have.

In the high luminance region extraction processing S41, as shown in FIG. 4, read grayscale original image (A) showing the relationship between the position and brightness, by now morphology processing, the maximum value filter and minimum value filter (B) ( C) is created, the difference (D ) between the original image (A) and the maximum value filter (C ) is obtained, and the bright portion compared to the surroundings, that is, the fluorescent portion 4a of the fluorescent still image 5 is specified.

In the three-dimensional position measurement S42, the examination region of the subject 1 is specified by the three-dimensional position measurement from the plurality of visible still images 6 (S43).
That is, when the same point (for example, both ends of the blade tip) of the subject 1 is displayed on the plurality of visible still images 6 photographed from a plurality of positions, the positions of the plurality of photographing cameras 22 and the positions on the image are used. The three-dimensional position of the position can be calculated. Further, the subject 1 is held by the swivel device 11, and the surface position of the subject 1 is limited to the peripheral position of the swivel device 11. Therefore, by specifying the peripheral position of the swivel device 11 as the inspection area, it is possible to erase an image at a position outside the swivel device 11.

  Next, the plurality of fluorescent still images 5 and the plurality of visible still images 6 are overlapped by image processing to display a plurality of superimposed images 7 (S44), and images other than the examination region are erased from the fluorescent still images 5 (S44). S45). Note that the superimposed image display S44 may be performed after step S45.

  Further, the position and size of the fluorescent portion 4a are calculated by measuring the three-dimensional position of the fluorescent portion 4a (S46).

In the turning step S5, the subject is turned around a predetermined axis.
For this turning, it is preferable to arbitrarily set a turning angle (for example, 180 degrees, 90 degrees, 60 degrees, 30 degrees, etc.) by numerical control or other means (such as a limit switch) so that a blind spot does not occur. .

  After this turning, the above-described steps S1 to S4 are repeated, and the entire surface of the inspection object is inspected so that no blind spot is formed. All the inspection results are stored in the storage device, and after the entire surface is inspected, the process proceeds to evaluation step S6. This number of repetitions is preferably performed at least twice (when the turning angle is 180 degrees).

In the evaluation step S6, the size of the plurality of superimposed images 7 and fluorescent portions obtained in the image processing step S4 is displayed and printed out, and compared with a predetermined threshold value to determine whether or not the subject 1 is acceptable. .
Note that this image display may be performed by separately displaying superimposed images of images taken from different positions or by sequentially rotating a plurality of superimposed images.
As a result of this fluorescence inspection, the object determined to have a defect candidate is transported to another line (not shown) and subjected to a more detailed inspection such as a visual inspection.

FIG. 5 is a schematic diagram of the fluorescence flaw detection method according to the present invention.
As shown in this figure, in the method of the present invention, a swiveling device 11 (turntable, a rotating mechanism of an arm during hanging transportation, etc.) for turning a subject 1 around a predetermined axis Z (for example, a vertical axis). ) To reduce the blind spot by shooting while turning. Further, the position and size of the fluorescent part are calculated by three-dimensional position measurement using a plurality of cameras 22.

  Therefore, the generation of blind spots can be prevented, and the entire inspection object can be inspected. Moreover, the actual dimension of the defect can be accurately measured, and the inspection accuracy is improved.

  In addition, this invention is not limited to embodiment mentioned above, Of course, it can change variously in the range which does not deviate from the summary of this invention.

It is a schematic diagram of the moving blade and vane which are subjects. 1 is an overall configuration diagram of a fluorescence flaw detector according to the present invention. It is a whole flowchart of the fluorescence flaw detection method by this invention. It is explanatory drawing of the morphology process in this invention. It is a schematic diagram of the fluorescence inspection method by this invention. It is a schematic diagram of the apparatus of patent document 2. FIG. It is a schematic diagram of the apparatus of patent document 4. FIG. 11 is a schematic diagram of an apparatus disclosed in Patent Document 5.

Explanation of symbols

1 subject (test object), 2 near UV, 3 visible light,
4 fluorescence, 4a fluorescence part, 5 fluorescence still image,
6 visible still images, 7 superimposed images,
DESCRIPTION OF SYMBOLS 10 Fluorescence flaw detector, 11 Turning apparatus, 12 Conveyance apparatus, 13 Position detection sensor,
14 Darkroom device (dark curtain, dark box), 16 black light, 18 white strobe,
20 long pass filter, 22 camera,
24 image processing device (computer), 25 storage device,
26 image display device, 27 communication control device

Claims (4)

A swiveling device capable of holding a specimen having a fluorescent agent or fluorescent magnetic powder permeated or adsorbed on the surface at a predetermined examination position and capable of swiveling around a predetermined axis;
A darkroom apparatus that surrounds the subject at the examination position and maintains the inside under low illuminance capable of photographing fine fluorescence;
A black light that irradiates the subject at the inspection position with near ultraviolet rays for fluorescence testing;
A white strobe for irradiating the subject at the examination position with visible light;
A long-pass filter that cuts off the near-ultraviolet light and passes fluorescence and visible light;
A plurality of imaging cameras for imaging the subject at the examination position through the long pass filter while shifting the time from a plurality of positions, and acquiring a fluorescence still image at the time of near ultraviolet irradiation and a visible still image at the time of visible light irradiation,
An image processing device for displaying a plurality of superimposed images by superimposing the plurality of fluorescent still images and a plurality of visible still images ,
The image processing device identifies an examination region of a subject from a plurality of visible still images by three-dimensional position measurement,
A fluorescent flaw detection apparatus characterized in that a high-intensity area extraction process using morphology processing is performed on the fluorescent still image to identify a fluorescent part and calculate a position and a size of the fluorescent part .   The image processing apparatus identifies an examination region of a subject from a plurality of visible still images by three-dimensional position measurement, and erases an image other than the examination region from the plurality of fluorescent still images. The fluorescent flaw detector described in 1. A stationary step in which a subject infiltrated or adsorbed with a fluorescent agent or fluorescent magnetic powder is placed at a predetermined examination position; and
Irradiating near-ultraviolet rays for fluorescent flaw detection to a subject at an examination position in a dark room, photographing each subject from a plurality of positions through a long pass filter, and obtaining a plurality of fluorescence still images, and
Shifting the step and time, irradiating the subject at the examination position with visible light, photographing each subject through a long pass filter from the plurality of positions, and obtaining a plurality of visible still images,
An image processing step of displaying a plurality of superimposed images by superimposing the plurality of fluorescent still images and a plurality of visible still images respectively by image processing;
A turning step for turning the subject around a predetermined axis ,
Identify the examination area of the subject from multiple visible still images by measuring the three-dimensional position,
A fluorescence flaw detection method characterized in that a high-luminance region extraction process using morphology processing is performed on the fluorescent still image, a fluorescent part is specified, and a position and a size of the fluorescent part are calculated . The fluorescent flaw detection method according to claim 3 , wherein an inspection region of a subject is specified from a plurality of visible still images by three-dimensional position measurement, and images other than the inspection region are erased from the plurality of fluorescent still images. .

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