JP2017181382A - Different crystal inspection device and inspection method of unidirectional coagulation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a different crystal inspection device and an inspection method of a unidirectional coagulation capable of detecting a fine different crystal section.SOLUTION: A different crystal inspection device of a unidirectional coagulation includes: an illumination section 3 for irradiating an inspection object area 102 of the unidirectional coagulation with light; an imaging section 2 for imaging the inspection object area 102; and a different crystal specification section 51 for configuring such that a rotation angle φ of a direction D of radiation about the inspection object area 102 is changed when the direction D of radiation of the light is projected onto a second plane orthogonal to a first plane including the inspection object area 102, the illumination section 3, and an imaging section 2, and specifying a different crystal section in the inspection object area 102 based on a plurality of image data whose rotation angle φ obtained by the imaging section 2 is different.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a unidirectionally solidified foreign crystal inspection apparatus and inspection method, and is useful when applied to detection of a different crystal part in a unidirectionally solidified casting.

  From the standpoint of improving efficiency, gas turbines and aircraft engines are becoming increasingly hot. Along with this, unidirectional solidified castings have been proposed as materials for turbine blades that can withstand high temperatures. In this type of unidirectionally solidified casting, casting distortion due to mold restraint may occur during solidification cooling after casting, and a different crystal part (recrystallized part) may occur. The different crystal part in the unidirectionally solidified casting has a low strength and causes cracking, which may cause a decrease in the fatigue strength of the turbine blade. Therefore, various inspection methods that can detect different crystal parts in the unidirectional solidified material have been proposed.

  Patent Document 1 discloses a method of detecting a different crystal region of a single crystal material using a difference in propagation speed of ultrasonic waves according to a crystal orientation. Specifically, an ultrasonic wave is incident from the surface of an object to be inspected made of a single crystal material, and a reflected wave from the back surface is detected. Then, at two or more locations, the time from the incidence of ultrasonic waves to the detection of the back surface reflected wave is measured. Based on the time difference at two or more locations thus obtained, the presence of a different crystal region is detected.

JP 2009-300371 A

  However, although the method described in Patent Document 1 can detect the presence of a somewhat large different crystal region, there is a problem that it is difficult to detect a fine different crystal part.

  The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a unidirectionally solidified foreign crystal inspection apparatus and inspection method capable of detecting fine different crystal parts.

  Japanese Patent Application No. 2015-0669905 (filed on March 30, 2015, hereinafter simply referred to as a prior application), which is a prior invention by the applicant of the present application, exists as a different crystal inspection apparatus that achieves the above object. This utilizes the phenomenon that when a predetermined region to be inspected of the unidirectional solidified material is irradiated with light, the reflection direction of light differs between a sound crystal part and a different crystal part.

  FIG. 1 is a schematic diagram conceptually showing the structure of a different crystal inspection apparatus according to a prior application for detecting a different crystal portion of a unidirectional solidified material using the above phenomenon. As shown in the figure, the different crystal inspection apparatus 1 basically includes an imaging unit 2 for imaging the inspection target region 102 and an illumination unit 3 for irradiating the inspection target region 102 with light. Yes. Here, the illuminating unit 3 rotates around the imaging direction C (perpendicular to the inspection target surface in the figure) that is the optical axis of the imaging unit 2 in the same posture, and captures an image of the inspection target region 102 at each rotational position.

More specifically, the imaging unit 2 captures a plurality of pieces of image data by imaging the inspection target region 102 of the unidirectional solidified product 100. As shown in FIG. region 102, orthogonal (in this case, perpendicular to the imaging direction C) to the first plane M which includes the imaging unit 2 and the illuminator 3 definitive when projected irradiation direction D ₁ of the light to the second plane N to, inspection areas 102 Is obtained by sequentially changing the rotation angle φ of the irradiation direction (hereinafter referred to as the projection irradiation direction) D ₁ ′. That is, for example, when projected irradiation direction D ₁ of the illumination unit 3 before irradiation direction changed to the second plane N, projection illumination direction D _{1 'is} defined. Further, 'when projected irradiation direction D ₂ of the second plane N, projection illumination direction D _2' illumination unit 3 after irradiation direction change is defined. As described above, the rotation angle φ of the illumination unit 3 is an angle between the projection irradiation direction D ₁ ′ before the irradiation direction change and the projection irradiation direction D ₂ ′ after the irradiation direction change on the second plane N. . Upon rotation of the illumination unit 3, so that a value rotation angle φ is greater than 0 degrees to change the irradiation direction D ₁ of the illumination unit 3 into the irradiation direction D _2.

  FIG. 3A shows an image of the surrounding portion 103 by the imaging unit 2 in a state where the illumination portion 3 irradiates the surrounding portion (surrounding base material portion portion which is a healthy portion) 103 in the inspection target region 102. The state at the time of acquiring data is shown. FIG. 3B illustrates a case where image data of the different crystal part 104 is acquired by the imaging unit 2 in a state where the illumination unit 3 irradiates light to the different crystal part (defective part) 104 in the inspection target region 102. Shows the state. 3A and 3B, the positional relationship between the imaging unit 2 and the illumination unit 3 with respect to the inspection target region 102 is the same.

  As shown in FIGS. 3A and 3B, the light irradiated by the illumination unit 3 is reflected by the crystal plane of the inspection target region 102. At this time, specular reflection with respect to the irradiation direction D of the illumination unit 3 is performed. In the (regular reflection) direction D ′, the amount of light is the largest. For example, in the example shown in FIG. 3A, since the imaging unit 2 is not located in the specular reflection direction D ′ reflected by the crystal plane of the surrounding part 103, in this case, the image data acquired by the imaging unit 2 Among them, the luminance of the peripheral portion (peripheral base material portion) 103 becomes small, and the region becomes dark. On the other hand, in the example shown in FIG. 3B, since the imaging unit 2 is located in the specular reflection direction D ′ reflected by the crystal plane of the different crystal unit 104, in this case, the image data acquired by the imaging unit 2 Among them, the brightness of the different crystal part 104 becomes high, and the region becomes bright.

  As described above, although the positional relationship between the imaging unit 2 and the illumination unit 3 with respect to the inspection target region 102 is the same, the luminance is different between the peripheral portion 103 and the different crystal portion 104. It is presumed that the crystal orientation is different between the peripheral portion 103 and the peripheral portion 103.

Therefore, as described above, by configuring so as to specify the different crystal part in the inspection target region 102 based on a plurality of image data having different rotation angles φ in the projection irradiation directions D ₁ ′ and D ₂ ′, Even different crystal parts can be detected with high accuracy.

That is, of the image data acquired by the imaging unit 2, if different crystal part is formed in a particular pixel, the luminance signal in the pixel, as shown in FIG. 4 (a), a maximum at theta _1. Luminance signal of peripheral portions is sound crystal unit with respect to this, as shown in FIG. 4 (b), a maximum at theta _2. Therefore, if a luminance signal for determination as shown in FIG. 4C is created by subtracting the other from one, for example, the different crystal part is specified based on the difference Δ between the maximum luminance and the minimum luminance in the luminance signal. can do. That is, when the difference Δ exceeds a predetermined threshold, it is determined that the different crystal portion is included in the pixel. As a result, even a fine different crystal can be detected with high accuracy.

  The detection principle of the prior application as described above is based on the premise that the crystal structure of the different crystal part is one type. That is, as shown in FIG. 3, one crystal orientation of the different crystal part 104 is formed with respect to the crystal face of the peripheral part 103 which is a healthy crystal part (in FIG. 3, with respect to the crystal face of the peripheral part 103, This is effective when the different crystal portion 104 is formed with a phase difference of 180 °.

  However, the crystal of the unidirectional solidified material, which is a material forming the turbine blades, is a cubic crystal. As shown in FIG. 5A, not only the crystal plane is unidirectional, but also FIG. ), The crystal plane is formed in two directions, or the crystal plane is formed in three directions as shown in FIG. Therefore, in the case shown in FIGS. 5B and 5C, the light incident on each surface is reflected as shown by the dotted line in the drawing as shown by the solid line in the drawing. Therefore, although it is a prior application having various features as compared with the prior art, there is still room for improvement in terms of detection accuracy. That is, in the case of a cubic crystal, it is necessary to consider the case where the crystal plane is two or three planes.

  The present invention solves the problems remaining in the prior application, and further enables detection of a different crystal part of a unidirectional solidified product with high accuracy, and is characterized by the following points.

1) A unidirectional solidified foreign crystal inspection device,
An illuminating unit for irradiating light to the inspection target region of the unidirectional solidified product,
An imaging unit for imaging the inspection target region;
When the irradiation direction of the light is projected onto a second plane orthogonal to the first plane including the inspection target region, the illumination unit, and the imaging unit, the rotation angle φ of the irradiation direction around the inspection target region An irradiation direction changing unit configured to change
A different crystal specifying unit for specifying a different crystal part in the inspection target region based on a plurality of image data with different rotation angles φ obtained by the imaging unit, and
The different crystal specifying unit obtains first to nth harmonic components by performing a fast Fourier transform on each pixel using the plurality of image data, and the first to nth harmonic components. Are each separated into an amplitude component and a phase component to determine a vector specified by the amplitude component and the phase component of the first to n-th harmonic components, and further, the first to n-th harmonics In each of the components, the different crystal part is specified based on the difference in the vector between a specific pixel and a peripheral pixel.

2) The different crystal specifying unit performs the calculation of the vector difference by specifying a filter size that defines a central part where the specific pixel exists and a peripheral part surrounding the central part.

3) The different crystal specifying unit calculates the difference between the vectors based on a luminance that is a mean square of the amplitude and the phase.

4) The different crystal specifying portion is determined to be the different crystal portion when any one of the vector differences based on the first to nth harmonic components exceeds a predetermined threshold. about.

5) The irradiation direction changing unit
A first annular track portion that is provided so as to surround the region to be inspected of the unidirectional solidified product and forms a track for rotating the illumination unit around the region to be inspected in the second plane. Including
The illumination unit is configured to be movable around the inspection target region along the first annular track portion so that the rotation angle φ changes.

6) A plurality of the illumination units are arranged so as to surround the imaging unit, and each of the illumination units can be turned on independently of each other,
The irradiation direction changing unit is configured to change the rotation angle φ by switching a lighting unit to be lit among a plurality of the lighting units.

7) The irradiation direction changing unit is provided so as to surround the imaging unit, includes a second annular track unit fixed to the imaging unit, and the illumination unit changes the rotation angle φ. It is configured to be movable around the imaging unit along the second annular track portion.

8) further comprising a dome illumination device in which a plurality of the illumination units are arranged along a hemispherical surface;
The illumination units of each of the dome illumination devices can be lit independently of each other,
The irradiation direction changing unit is configured to change the rotation angle φ by switching a lighting unit to be lit among a plurality of the lighting units arranged along the hemisphere.

9) The imaging unit is configured to be movable in the first plane or the second plane.

10) It further includes a robot arm to which the illumination unit and the imaging unit are attached.

11) The irradiation direction changing unit
In addition to the rotation angle φ, the tilt angle θ of the irradiation direction around the inspection target region in the first plane is changed,
The different crystal specifying part is configured to specify the different crystal part based on a plurality of pieces of image data having different inclination angles θ and rotation angles φ obtained by the imaging unit.

12) A method for examining different crystals of a unidirectional solidified product,
A light irradiating step of irradiating light through the illuminating unit to the inspection target region of the unidirectional solidified product;
An imaging step of capturing the inspection target area with an imaging unit and collecting image data of the inspection target area;
When the irradiation direction of the light is projected onto a second plane orthogonal to the first plane including the inspection target region, the illumination unit, and the imaging unit, the rotation angle φ of the irradiation direction around the inspection target region An irradiation direction changing step for changing
A different crystal specifying step for specifying a different crystal part in the inspection target region based on a plurality of image data having different rotation angles φ obtained by the imaging step, and
In the different crystal specifying step, first to n-th harmonic components are obtained by performing fast Fourier transform on each pixel using the plurality of image data, and the first to n-th harmonic components are obtained. Are each separated into an amplitude component and a phase component to determine a vector specified by the amplitude component and the phase component of the first to n-th harmonic components, and further, the first to n-th harmonics In each of the components, the different crystal part is specified based on the difference in the vector between a specific pixel and a peripheral pixel.

13) In the different crystal specifying step, the vector difference is calculated by specifying a filter size that defines a central portion where the specific pixel exists and a peripheral portion surrounding the central portion.

14) In the different crystal specifying step, the difference between the vectors is calculated based on a luminance that is a mean square of the amplitude and the phase.

15) In the different crystal specifying part, when any one of the vector differences based on the first to n-th harmonic components exceeds a predetermined threshold value, it is determined as the different crystal part. about.

  According to the present invention, by specifying a different crystal part in the region to be inspected based on a plurality of image data having different rotation angles φ obtained by the imaging unit, even a fine different crystal part has high accuracy. Can be detected. Moreover, since the image data is subjected to fast Fourier transform for each pixel to obtain the first to nth harmonic components, it is possible to appropriately detect different crystal parts in each crystal plane even when it has a plurality of crystal planes. Can do.

It is a schematic diagram which shows the structure of the different crystal inspection apparatus which detects the different crystal part of a unidirectional solidified material. It is explanatory drawing shown about the example of a change of the irradiation direction of an irradiation part. It is a schematic diagram for demonstrating the principle which a brightness | luminance difference produces between a different crystal part (different crystal part) and a peripheral part with an irradiation direction. It is a figure which shows a luminance signal, (a) is a waveform diagram in a different crystal part, (b) is a waveform diagram in a healthy part, (c) is a waveform figure at the time of taking the difference of both. It is a schematic diagram which shows notionally the light which injects into three types of each crystal plane, and the light reflected by each crystal plane. It is a perspective view which shows the structure of the different crystal inspection apparatus which concerns on 1st Embodiment of this invention. It is a flowchart which shows the process sequence of the different crystal specific | specification part in each embodiment of this invention. It is a wave form diagram which shows the waveform of the 1st-3rd harmonic obtained as a result of the process of a different crystal specific part. It is a schematic diagram which shows the vector which combined the phase and amplitude obtained by a fast Fourier transform. It is a figure which shows the aspect at the time of processing of image data, (a) is a schematic diagram which shows several image data notionally, (b) is a schematic diagram which extracts and shows the filter. It is a perspective view which shows the structure of the different crystal inspection apparatus which concerns on 2nd Embodiment of this invention. It is a perspective view which shows the structure of the different crystal inspection apparatus which concerns on 3rd Embodiment of this invention. It is a perspective view which shows the structure of the different crystal inspection apparatus which concerns on 4th Embodiment of this invention. It is a figure which shows the foreign material detection apparatus provided with a robot arm, (a) is a schematic block diagram of the state which put the unidirectional solidification wing vertically, (b) is a schematic block diagram of the state which put the unidirectional solidification wing horizontally. It is a flowchart which shows the procedure of the different-crystal test | inspection method of the unidirectional solidified material of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that each embodiment described below is merely an example, and there is no intention of excluding various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the following embodiments can be implemented with various modifications without departing from the spirit thereof, and can be selected as necessary or can be appropriately combined.
In FIG. 1 and each of the following figures, the same parts are denoted by the same reference numerals, and redundant description is omitted.

<First Embodiment>
FIG. 6 is a perspective view showing the configuration of the different crystal inspection apparatus according to the first embodiment of the present invention. As shown in the figure, a unidirectional solidified foreign crystal inspection device (hereinafter referred to as a different crystal inspection device) 1 according to the present embodiment includes a different crystal portion existing on the surface layer of the unidirectional solidified material 100. It is a device for detection. The unidirectional solidified material 100 is a product obtained by solidifying molten metal in a certain direction under a unidirectional temperature gradient, and is used for products requiring heat resistance such as gas turbines and aircraft engines. Is a unidirectional casting. Further, the different crystal part is a region having a partially different crystal orientation in the unidirectional solidified product 100.

  As illustrated in FIG. 6, the different crystal inspection apparatus 1 includes an imaging unit 2 for imaging the inspection target region 102, an illumination unit 3 for irradiating the inspection target region 102 with light, and an irradiation direction of the illumination unit 3. An irradiation direction changing unit 4 for changing D and an image processing apparatus 5 including a different crystal specifying unit 51 for specifying a different crystal part based on image data acquired by the imaging unit 2 are provided.

  The imaging unit 2 is configured to capture a plurality of image data by capturing an image of the inspection target region 102 in the unidirectional solidified material 100. The image data acquired by the imaging unit 2 is sent to the image processing device 5. In the illustrated example, the imaging unit 2 has an imaging direction C along the vertical direction in order to capture an image of the unidirectional solidified material 100 located immediately below. The illumination unit 3 is configured to irradiate the inspection target region 102 of the unidirectional solidified material 100 with light. The illumination unit 3 may include, for example, an LED irradiator or a halogen irradiator.

  The irradiation direction changing unit 4 is configured to change the irradiation direction D of the illumination unit 3 with respect to the inspection target region 102. Specifically, as described above with reference to FIG. 2, the light irradiation direction D <b> 1 is projected onto the second plane N that is orthogonal to the first plane M including the inspection target region 102, the imaging unit 2, and the illumination unit 3. The rotation direction φ of the irradiation direction around the inspection target region 102, that is, the projection irradiation direction D1 ′ is changed. For example, when the irradiation direction D1 of the illumination unit 3 before changing the irradiation direction is projected onto the second plane N, the projection irradiation direction D1 'is obtained. Further, when the irradiation direction D2 of the illumination unit 3 'after changing the irradiation direction is projected onto the second plane N, the projection irradiation direction D2' is obtained. In the second plane N, the irradiation direction changing unit 4 has a rotation angle φ that is an angle between the projection irradiation direction D1 ′ before changing the irradiation direction and the projection irradiation direction D2 ′ after changing the irradiation direction exceeding 0 degree. The irradiation direction D of the light irradiated from the illumination unit 3 is changed so as to be a value.

  Further, as shown in FIG. 2, the irradiation direction changing unit 4 is configured to change the inclination angle θ of the irradiation direction D <b> 1 around the inspection target region 102 in the first plane M in addition to the rotation angle φ. You may do it. Here, the inclination angle θ is an angle of the irradiation direction D1 with respect to the second plane N.

  The irradiation direction changing unit 4 in the present embodiment has a first annular track portion 41 that forms a track for the illumination unit 3 to rotate. The first annular track portion 41 is disposed so as to surround the inspection target region 102 of the unidirectional solidified product 100, and an illumination unit around the inspection target region 102 in the second plane N (see FIG. 2). 3 forms a trajectory for turning. Further, the illumination unit 3 is configured to be movable around the inspection target region 102 along the first annular track portion 41 so that the rotation angle φ changes.

  More specifically, the first annular track portion 41 includes an inner ring 41a and an outer ring 41b configured to be rotatable relative to the inner ring 41a. The inner ring 41a is fixed to the outer peripheral surface of the disk-like mounting table 10 on which the unidirectional solidified product 100 is mounted. The outer ring 41b is disposed on the outer peripheral side of the inner ring 41a. An annular member 42 is attached to the outer peripheral side of the outer ring 41b, and a column part 43 for supporting the illumination unit 3 is fixed to the outer ring 41b via the annular member 42. And the outer ring | wheel 41b, the annular member 42, the illumination part 3, and the support | pillar part 43 can be rotated by the drive mechanism which is not shown in figure. At this time, the inner ring 41A, the mounting table 10, and the unidirectional solidified material 100 are stationary. The imaging unit 2 is supported by the column unit 21. Since the support column 21 is attached to a stationary part, the imaging unit 2 is kept stationary regardless of the rotation of the illumination unit 3.

  Moreover, the different crystal inspection apparatus 1 may further include a control device 12 including an illumination control unit 13 and an imaging control unit 14. The illumination control unit 13 controls the lighting of the illumination unit 3 and adjusts the rotation of the illumination unit 3 by controlling a driving mechanism (not shown). The imaging control unit 14 controls the imaging timing in the imaging unit 2 so as to be synchronized with the rotation of the illumination unit 3 and the lighting of the illumination.

  According to such a configuration, the rotation angle φ in the irradiation direction (see FIG. 2) can be freely adjusted by moving the illumination unit 3 around the inspection target region 102 along the first annular track portion 41. . Thus, it is possible to detect the different crystal part with high accuracy.

  The image processing apparatus 5 includes a different crystal specifying unit 51 for specifying a different crystal part. The different crystal specifying unit 51 of the present embodiment is based on a plurality of image data obtained by the imaging unit 2 having different rotation angles φ (for example, 12 sheets collected at every 30 ° rotation angle φ). The different crystal part in 102 is specified. At this time, image data is subjected to fast Fourier transform (hereinafter abbreviated as FFT) for each pixel. As a result, not only the first harmonic component of each pixel but also the second harmonic component and the third harmonic component are detected. Therefore, the reflected light components from the three types of crystal planes shown in FIG. 5 can be detected. Since the crystal structure of the unidirectionally solidified casting that is the inspection object in the present embodiment is a cubic crystal, all the reflected light is detected if the harmonics from the first order to the third order are detected. Become.

  FIG. 7 is a flowchart showing the processing procedure of the different crystal specifying unit in each embodiment of the present invention. The process in the different crystal specific | specification part 51 is demonstrated based on the same figure.

1) A plurality of pieces of image data are acquired by changing the irradiation direction of the illumination light (see ST1). This image data is data obtained by imaging the surface of the unidirectional solidified product 100 in the inspection target region 102 (see FIG. 6) acquired by changing the rotation angle φ by 30 °, for example, and making one rotation (360 °). is there.

2) Perform FFT on each pixel using a plurality of image data (see ST2). As a result, a luminance signal as schematically shown in FIG. 8 is obtained for each pixel. 8A shows the first harmonic, FIG. 8B shows the second harmonic, and FIG. 8C shows the third harmonic. In the image data acquired by the imaging unit 2 (see FIG. 6), the first to third harmonics shown in FIGS. 8A to 8C are mixed. Therefore, by extracting each by FFT, it is possible to obtain information on all reflected light shown in FIG. Since the waveforms of the first to third harmonics shown in FIGS. 8A to 8C are normalized, they have almost the same luminance level, but actually the second harmonic level. Is smaller than the first harmonic, and the luminance of the third harmonic is even smaller.

3) In each pixel, an amplitude component and a phase component are separated to obtain a predetermined vector (see ST3). This is executed for all pixels of all image data. As shown in FIG. 9, the vector thus obtained represents the magnitude by the amplitude component and the direction by the phase component. In the present embodiment, a predetermined comparison process or the like is performed using the vector.

4) A filter size is defined which is the size of the central region 121 (see FIG. 10B) of the filter (120 in FIG. 10B) and the peripheral region 122 (see FIG. 10B) (see ST4). . That is, the number of pixels included in the central region 121 is defined. Thereby, the resolution can be defined. Note that when the central region 121 includes a plurality of pixels, the pixels are averaged and used as a vector.

5) The luminance is compared with the peripheral portion for each harmonic (see ST6). The luminance in this case is a value obtained by squaring the amplitude forming each vector and the phase (see ST5). Here, in the prior application, the predetermined comparison processing is simply performed based on only the luminance. However, the accuracy of the comparison processing can be improved by using the vector as in the present application. That is, when only luminance is used as a reference, the difference in luminance between the peripheral region 122 and the central region 121 is small, but the phase difference may be large. When the phase difference is large, the difference in luminance only is below the threshold value. This is because it may be a different crystal part.

6) As a result of the comparison in ST5, if the difference in vector brightness between the two exceeds the threshold value, it is determined that a different crystal part exists and the location is specified (see ST6). Such a position can be easily identified by referring to the position of the corresponding pixel in the screen data. Here, various values can be considered as the threshold value. That is, although there is no special limitation, a unique threshold value is set corresponding to each of the first to nth harmonics, and when any of the threshold values exceeds the threshold value, a method of determining a different crystal part Alternatively, a method of adding numerical values related to the first to nth harmonics and determining that the added crystal exceeds a threshold value is a different crystal part.

7) As a result of the comparison in ST5, when the difference in vector brightness is equal to or less than the threshold value, it is determined that there is no different crystal part (see ST7).

  FIG. 10A is a schematic diagram conceptually showing a plurality of image data processed by the image processing apparatus 5, and FIG. 10B is a schematic diagram showing an extracted filter. As shown in FIG. 10, the different crystal specifying unit 51 stores a plurality of pieces of image data 108 obtained at each rotation angle φ (see FIG. 2), and the average of the surrounding region 122 (including 122 A and 122 B). The luminance is calculated, and the average luminance is used as the reference luminance. The luminance in this case is obtained by squaring the phase and amplitude in the vector having the phase and amplitude as components as described above.

  In the measurement of luminance, first, the image data 108 is scanned using a filter 120 having a predetermined filter size. Then, the brightness of the center area 121 of the filter 120 is measured, and this is used as the brightness of the position of interest in the image data 108. In addition, the luminance of the surrounding region 122 (including 122A and 122B) of the central region 121 is measured, and the average luminance in the surrounding portion is calculated using the measured plurality of luminances.

  As shown in FIG. 10, the different crystal specifying unit 51 calculates an average luminance for an area composed of a target position (target position) 120 and its surroundings (including 122 A and 122 B) in the image data 108, and calculates the average brightness. The luminance may be configured to be used as the reference luminance. For example, in measuring the luminance, first, the image data 108 is scanned using the filter 120 having a predetermined filter size. Then, the brightness of the center area 121 of the filter 120 is measured, and this is used as the brightness of the position of interest in the image data 108. In addition, the brightness of the surrounding area 122 (including 122A and 122B) of the center area 121 is measured, and the average brightness in the surrounding area is calculated using the brightness in the center area 122 and the plurality of brightness in the surrounding area 122.

  In these embodiments, the luminance of the surrounding region 122 may be measured for at least some of the regions 122A or 122B among the plurality of regions 122A and 122B partitioned in a grid pattern. For example, when the regions 122A and the regions 122B are alternately arranged, the luminance of the surrounding region 122 may be measured for the region 122A or the region 122B. According to these configurations, it is possible to appropriately obtain the reference luminance indicating the average luminance in the periphery of the position of interest.

In some embodiments described above, the different crystal identification unit 51 may be configured to perform a low-pass filter process on at least a part of the image data 108 to calculate the reference luminance. In this case, it is possible to appropriately acquire the reference luminance indicating the average luminance in the peripheral portion of the position of interest by simple processing using a low-pass filter.

  The configuration and function of the image processing apparatus 5 as described above are the same in the second to fifth embodiments described below.

Second Embodiment
FIG. 11 is a perspective view showing the configuration of the different crystal inspection apparatus 1 according to the second embodiment. As shown in FIG. 11, the different crystal inspection apparatus 1 according to this embodiment includes a plurality of illumination units 3. The plurality of illumination units 3 are arranged so as to surround the imaging unit 2, and each illumination unit 3 can be turned on independently of each other. The irradiation direction changing unit 4 changes the rotation angle φ (see FIG. 2) in the irradiation direction by switching the lighting unit 3 that is turned on among the plurality of lighting units 3.

  Here, the plurality of illumination units 3 are attached to an annular support unit 44 disposed so as to surround the imaging unit 2. The annular support portion 44 may be attached to the column portion 21 for supporting the imaging unit 2. A plurality of illumination parts 3 are arranged on the annular support part 44 at a predetermined interval. The bottom surfaces of the plurality of illumination units 3 may be substantially the same height as the bottom surface of the imaging unit 2.

  Moreover, the different crystal inspection apparatus 1 according to the present embodiment includes a control device 12 including an illumination control unit 13 and an imaging control unit 14. The illumination control unit 13 is configured to control lighting. In this configuration example, the illumination control unit 13 plays the role of the irradiation direction changing unit 4. That is, the illumination control unit 13 switches the illumination unit 3 to be turned on among the plurality of illumination units 3, and changes the rotation angle φ (see FIG. 2) in the irradiation direction. For example, the irradiation direction changing unit 4 (lighting control unit 13) controls each lighting unit 3 so that the lighting units 3 are sequentially turned on in the direction of arrow E in the drawing. The imaging control unit 14 controls the imaging timing in the imaging unit 2 so as to be synchronized with the lighting of the illumination by the illumination control unit 13.

  According to such a configuration, the rotation direction φ (see FIG. 2) in the irradiation direction D is switched by switching the illumination unit 3 that is turned on among the plurality of illumination units 3 by the irradiation direction changing unit 4 (illumination control unit 13). Can be adjusted freely. As a result, it is possible to detect the different crystal part with high accuracy. In addition, since the lighting unit 3 that is turned on is switched instead of moving the lighting unit 3, the rotation angle φ in the irradiation direction D can be quickly changed. As a result, the time required to acquire image data for a plurality of rotation angles φ can be reduced, and inspection of different crystal parts can be performed efficiently.

<Third Embodiment>
FIG. 12 is a perspective view showing a configuration of a different crystal inspection apparatus 1 obtained by modifying the second embodiment shown in FIG. In the present embodiment, the same components as those in FIG. 11 are denoted by the same reference numerals, and the description thereof is omitted. As illustrated in FIG. 12, the irradiation direction changing unit 4 includes a second annular track portion 45 that is provided so as to surround the imaging unit 2 and is fixed to the imaging unit 2. The illumination unit 3 is configured to be movable around the imaging unit 2 along the second annular track unit 45 so that the rotation angle φ (see FIG. 2) in the irradiation direction D changes.

  According to such a configuration, the rotation angle φ in the irradiation direction D can be freely adjusted by moving the illumination unit 3 around the imaging unit 2 along the second annular track portion 45. As a result, it is possible to detect the different crystal part with high accuracy.

<Fourth embodiment>
FIG. 13 is a perspective view showing a configuration of a different crystal inspection apparatus 1 according to the fourth embodiment of the present invention. As shown in the figure, the different crystal inspection apparatus 1 in this embodiment has a dome illumination apparatus 15 in which a plurality of illumination units 3 are arranged along a hemispherical surface. Each illumination unit 3 of the dome illumination device 15 is configured to be able to light independently of each other. Each illumination unit 3 may be, for example, a small spot illumination. The irradiation direction changing unit 4 changes the rotation angle φ by switching the lighting unit 3 to be lit among the plurality of lighting units 3 arranged along the hemispherical surface. Here, the hemispherical surface not only represents a hemispherical surface in a strict sense, but also includes a surface having a generally hemispherical shape.

  Further, the different crystal inspection apparatus 1 includes a control device 12 including an illumination control unit 13 and an imaging control unit 14. The illumination control unit 13 controls lighting of each illumination unit 3. In the present embodiment, the illumination control unit 13 plays the role of the irradiation direction changing unit 4. That is, the illumination control unit 13 switches the illumination unit 3 to be turned on among the plurality of illumination units 3, and the rotation angle φ in the irradiation direction (see FIG. 2) changes. The imaging control unit 14 is configured to control the imaging timing in the imaging unit 2 so as to be synchronized with the lighting of the illumination by the illumination control unit 13.

  According to this configuration, the irradiation direction changing unit 4 (illumination control unit 13) can freely adjust the rotation angle φ in the irradiation direction by switching the lighting unit 3 to be lit among the plurality of lighting units 3. it can. As a result, it is possible to detect the different crystal part with high accuracy. In addition, since the lighting unit 3 that is turned on is switched instead of moving the lighting unit 3, the rotation angle φ in the irradiation direction (see FIG. 2) can be quickly changed. As a result, the time required to acquire image data for a plurality of rotation angles φ can be reduced, and inspection of different crystal parts can be performed efficiently. Furthermore, by using the dome illumination device 15, more illumination units 3 can be provided. For example, an illumination unit row formed by a plurality of illumination units 3 arranged along a circumferential line intersecting with the hemispherical second plane N (see FIG. 2) of the dome illumination device 15 is represented by the second plane N. A plurality of rows can be provided along the direction perpendicular to the. In this case, it is possible to freely adjust not only the rotation angle φ but also the inclination angle θ (see FIG. 2) of the light irradiation direction by switching the illumination unit 3 to be lit among the plurality of illumination units 3. Become.

<Fifth Embodiment>
In the first to fourth embodiments, the following configuration may be further provided. In the following description, the same parts as those in the first to fourth embodiments are denoted by the same reference numerals, and overlapping descriptions are omitted.

  The imaging unit 2 is formed to be movable in the first plane M or the second plane N. Depending on the crystal orientation of the different crystal part, the positional relationship between the imaging unit 2 and the inspection target region 102 suitable for detecting the different crystal part can be changed. In this regard, according to the above configuration, since the imaging unit 2 can move in the first plane M or the second plane N, the inspection of the different crystal part is performed while changing the positional relationship between the imaging unit 2 and the inspection target region 102. It can be performed. As a result, the robustness of the inspection of the different crystal part is improved.

  Further, the irradiation direction changing unit 4 is configured to change the inclination angle θ (see FIG. 2) of the irradiation direction D1 around the inspection target region 102 in the first plane M in addition to the rotation angle φ. Also good. For example, the inclination angle θ is an angle of the irradiation direction D1 with respect to the second plane N. In this case, the different crystal specifying unit 51 is configured to specify the different crystal part based on a plurality of pieces of image data having different inclination angles θ and rotation angles φ obtained by the imaging unit 2.

  As shown in FIGS. 14A and 14B, the different crystal inspection apparatus 1 includes a robot arm 17 to which the illumination unit 3 and the imaging unit 2 are attached. 14 (a) and 14 (b) are schematic configuration diagrams of the different crystal inspection apparatus 1 having the robot arm 17, and FIG. 14 (a) shows the unidirectional solidified blade 100 to be inspected. FIG. 14B shows the state of the different crystal inspection apparatus 1 when the unidirectional solidified blade 100 is in the horizontal position.

  In the present embodiment, a unidirectional solidified blade (turbine cast blade) is illustrated as the unidirectional solidified product 100. The unidirectional solidified blade 100 is placed on a pedestal 61 installed on a swivel base 60. In FIG. 14A, the unidirectional solidified blade 100 is placed on the gantry 61 in a vertically placed state, and in FIG. 14B, the unidirectional solidified blade is placed on the pedestal 61 in a horizontally placed state. Is placed. The posture of the unidirectional solidified blade 100 is appropriately set according to the inspection target region 102. A mechanism including the illumination unit 3 and the imaging unit 2 as shown in the first to fourth embodiments is attached to the tip of the robot arm 17. Here, the robot arm 17 has a plurality of joints, and the postures of the imaging unit 2 and the illumination unit 3 can be adjusted.

  According to such a configuration, it is possible to efficiently inspect different crystal parts at various locations in the unidirectional solidified product (unidirectional solidified blade) 100 by operating the robot arm 17.

  As mentioned above, although the different-crystal test | inspection apparatus based on this invention was demonstrated with the 1st-5th embodiment, it is as follows when the requirements which this apparatus should have are put together. The distance from the imaging unit 2 and the illuminating unit 3 to the one-sided coagulum 100 that is the inspection object is constant, and either the imaging axis direction of the imaging unit 2, the optical axis direction of the illuminating unit 3, or the rotation angle φ changes. It only has to be a structure. The different crystal inspection apparatuses according to the first to fifth embodiments all satisfy such a condition.

<Sixth Embodiment>
The present embodiment is a method for examining a different crystal of a unidirectional solidified product. In the different crystal inspection method according to the present embodiment, as shown in the flowchart of FIG. 15, the etching process ST11, the light irradiation step ST12, the imaging step ST13, the irradiation direction changing step ST14, and the different crystal specifying step ST15 are performed. I have.

  In the etching process ST11, an etching process is performed on the surface of the unidirectional solidified material. Since the surface layer of the unidirectional solidified material is normally in an amorphous state, the surface layer is removed by etching to expose the crystal part.

  In the light irradiation step ST12, light is irradiated to the inspection target region of the unidirectional solidified product. The specific mode of light irradiation to the inspection target area is as described above.

  The imaging step ST13 images the inspection target region in the unidirectional solidified product.

  The irradiation direction changing step ST14 is a rotation angle of the irradiation direction around the inspection target area when the irradiation direction of light is projected onto a second plane orthogonal to the first plane including the inspection target area, the illumination unit, and the imaging unit. Change φ.

  The different crystal specifying step ST15 is based on a plurality of image data having different rotation angles φ obtained by the imaging step ST13 (for example, 12 sheets collected every rotation of the rotation angle φ by 30 °) in the inspection target region. This is a processing step for specifying a different crystal part, and includes an image processing step ST151, a determination step ST152, a position specifying step ST153, and a notification step ST154 without a different crystal part. In the image processing step ST151, FFT is performed for each pixel using a plurality of pieces of image data, and each pixel is decomposed into an amplitude component and a phase component, and expressed in a direction defined by the phase and a size defined by the amplitude. Create a vector for each pixel. This is obtained for each of the three types of harmonics of primary, secondary, and tertiary.

In the determination step ST153, the luminance based on the vector is obtained for each of the first to third harmonics, the luminance is compared with the luminance of the peripheral portion, and whether or not the difference between both exceeds a predetermined threshold value. judge. As a result, if it exceeds, the process proceeds to the position specifying step ST153. In position specifying step ST153, the position where the different crystal part is formed is specified based on the position of the corresponding pixel in the screen data. The luminance referred to here is a value obtained as the mean square of the amplitude and phase, which are vector components.
On the other hand, as a result of the determination process in determination step ST153, if there is no different crystal part, the fact that there is no different crystal part is notified by means such as a display device or a printout.

  According to such a different crystal inspection method, the first to third harmonics are generated for each pixel by FFT based on a plurality of collected image data. And the component of the reflected light in the case of the three surfaces can also be reflected in the analysis result. As a result, the different crystal part in the inspection target region can be specified with high accuracy.

  As the unidirectional solidified product to be inspected in the different crystal inspection method according to the sixth embodiment, a turbine casting blade of a gas turbine or an aircraft engine is suitable. In a turbine casting blade of a gas turbine or an aircraft engine, casting distortion due to mold restraint may occur during solidification cooling after casting, and a different crystal part may be generated. Since the different crystal part is a different crystal part having a crystal orientation different from that of the base material, the different crystal part of the turbine casting blade of the gas turbine or the aircraft engine is accurately obtained by the different crystal inspection method according to the sixth embodiment. This is because it can be detected.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the first to third harmonics are obtained because the inspection target is a cubic crystal having three types of crystal orientation planes. When this becomes a hexagonal crystal, the order of the harmonics may be increased as necessary. That is, the harmonic order is also selected according to the number of crystal orientation planes.

DESCRIPTION OF SYMBOLS 1 Different crystal inspection apparatus 2 Imaging part 3 Illumination part 4 Irradiation direction change part 5 Image processing apparatus 10 Mounting stand 12 Control apparatus 13 Illumination control part 14 Imaging control part 15 Dome illumination apparatus 17 Robot arm 41 1st cyclic | annular track part 45 2nd Annular orbital part 51 Different crystal specifying part 100 Unidirectional solidified substance 102 Inspection object area 103 Peripheral part 104 Different crystal part 108 Image data 120 Filter M First plane N Second plane θ Inclination angle φ Rotation angle

Claims (15)

A unidirectional solidified foreign crystal inspection device,
An illuminating unit for irradiating light to the inspection target region of the unidirectional solidified product,
An imaging unit for imaging the inspection target region;
When the irradiation direction of the light is projected onto a second plane orthogonal to the first plane including the inspection target region, the illumination unit, and the imaging unit, the rotation angle φ of the irradiation direction around the inspection target region An irradiation direction changing unit configured to change
A different crystal specifying unit for specifying a different crystal part in the inspection target region based on a plurality of image data with different rotation angles φ obtained by the imaging unit, and
The different crystal specifying unit obtains first to nth harmonic components by performing a fast Fourier transform on each pixel using the plurality of image data, and the first to nth harmonic components. Are each separated into an amplitude component and a phase component to determine a vector specified by the amplitude component and the phase component of the first to n-th harmonic components, and further, the first to n-th harmonics In each component, the different crystal inspection of the unidirectional solidified product is characterized in that the different crystal portion is specified based on the difference in the vector between a specific pixel and a peripheral pixel. apparatus.   The difference crystal specifying unit performs the calculation of the vector difference by defining a filter size that defines a central part where the specific pixel exists and a peripheral part surrounding the central part. 2. The unidirectionally solidified foreign crystal inspection apparatus according to 1.   3. The unidirectional solidified product according to claim 1, wherein the different crystal specifying unit calculates a difference between the vectors based on a luminance that is a mean square of the amplitude and the phase. Crystal inspection device.   The different crystal specifying part is determined to be the different crystal part when any one of the vector differences based on the first to nth harmonic components exceeds a predetermined threshold. The unidirectionally solidified foreign crystal inspection apparatus according to any one of claims 1 to 3, wherein the unidirectional solidified foreign crystal inspection apparatus is provided. The irradiation direction changing unit is
A first annular track portion that is provided so as to surround the region to be inspected of the unidirectional solidified product and forms a track for rotating the illumination unit around the region to be inspected in the second plane. Including
The said illumination part is comprised so that the circumference | surroundings of the said test | inspection area | region can be moved along the said 1st cyclic | annular track | orbit part so that the said rotation angle (phi) may change. 5. The unidirectional solidified foreign crystal inspection apparatus according to any one of claims 4 to 4. A plurality of the illumination units are arranged so as to surround the imaging unit, and each of the illumination units can be lit independently of each other,
The said irradiation direction change part is comprised so that the said rotation angle (phi) may be changed by switching the illumination part lighted among the said some illumination parts, The any one of Claims 1-4 characterized by the above-mentioned. The unidirectional solidified foreign crystal inspection apparatus according to one item.   The irradiation direction changing unit is provided so as to surround the imaging unit, includes a second annular track unit fixed to the imaging unit, and the illumination unit changes the rotation angle φ so that the rotation angle φ changes. The unidirectionally solidified heterocrystal inspection apparatus according to any one of claims 1 to 4, wherein the unidirectional solidified foreign crystal inspection device is configured to be movable around the imaging unit along a two-annular track portion. A dome illumination device in which a plurality of the illumination units are arranged along a hemispherical surface;
The illumination units of each of the dome illumination devices can be lit independently of each other,
The irradiation direction changing unit is configured to change the rotation angle φ by switching a lighting unit to be lit among a plurality of the lighting units arranged along the hemisphere. The unidirectional solidified foreign crystal inspection apparatus according to any one of claims 1 to 4.   The unidirectional solidified heterocrystal according to any one of claims 1 to 8, wherein the imaging unit is configured to be movable in the first plane or the second plane. Inspection device.   The unidirectional solidified foreign crystal inspection apparatus according to any one of claims 1 to 9, further comprising a robot arm to which the illumination unit and the imaging unit are attached. The irradiation direction changing unit is
In addition to the rotation angle φ, the tilt angle θ of the irradiation direction around the inspection target region in the first plane is changed,
The said different crystal specific part is comprised so that the said different crystal part may be specified based on several image data from which the said inclination angle (theta) and the said rotation angle (phi) obtained by the said imaging part differ. The unidirectional solidified foreign crystal inspection apparatus according to any one of claims 1 to 10. A method for examining different crystals of a unidirectional solidified product,
A light irradiating step of irradiating light through the illuminating unit to the inspection target region of the unidirectional solidified product;
An imaging step of capturing the inspection target area with an imaging unit and collecting image data of the inspection target area;
When the irradiation direction of the light is projected onto a second plane orthogonal to the first plane including the inspection target region, the illumination unit, and the imaging unit, the rotation angle φ of the irradiation direction around the inspection target region An irradiation direction changing step for changing
A different crystal specifying step for specifying a different crystal part in the inspection target region based on a plurality of image data having different rotation angles φ obtained by the imaging step, and
In the different crystal specifying step, first to n-th harmonic components are obtained by performing fast Fourier transform on each pixel using the plurality of image data, and the first to n-th harmonic components are obtained. Are each separated into an amplitude component and a phase component to determine a vector specified by the amplitude component and the phase component of the first to n-th harmonic components, and further, the first to n-th harmonics A method for examining a different crystal of a unidirectional solidified product, wherein the different crystal part is specified based on a difference between the vector between a specific pixel and a peripheral pixel in each component.   The calculation of the vector difference is performed by defining a filter size that defines a central portion where the specific pixel exists and a peripheral portion surrounding the specific pixel in the different crystal specifying step. 12. A method for inspecting a different crystal of a unidirectional solidified product according to item 12.   The unidirectional solidified product difference according to claim 12 or 13, wherein, in the different crystal specifying step, the difference between the vectors is calculated based on a luminance that is a mean square of the amplitude and the phase. Crystal inspection method.   In the different crystal specifying part, when any one of the vector differences based on the first to nth harmonic components exceeds a predetermined threshold, it is determined that the different crystal part is the different crystal part. The unidirectionally solidified heterocrystal inspection device according to any one of claims 12 to 14, wherein

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