Hardness testing machine and computer-readable storage medium

Abstract

The present invention provides a hardness testing machine and a program capable of simplifying the setting of a test position. The hardness testing machine (1) includes: an image acquisition unit (control unit (100)) that acquires an image (surface image) of the surface of a specimen (S) captured by a photographing unit (photographing unit (10)); a determination unit (control unit (100)) that determines an unsuitable region (NR) within the image that is not suitable for a hardness test according to given conditions based on the image of the surface of the specimen (S); and a test position setting unit (control unit (100)) that sets a test position in a region other than the unsuitable region (NR) determined by the determination unit.

Description

Technical Field

[0001] The present invention relates to a hardness testing machine and a computer-readable storage medium. Background Art

[0002] Conventionally, a hardness testing machine is known that measures the hardness of a specimen based on the size of an indentation formed by pressing a indenter against the specimen (workpiece) with a given test force. In such a hardness testing machine, for example, a hardness testing machine has been proposed that can avoid the position where an indentation was formed in a previous test and automatically set a position suitable for a retest when retesting a specimen that has undergone a previous test (for example, refer to Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2012-78307 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] However, in the hardness testing machine disclosed in Patent Document 1 above, at the time of the initial test, the user needs to visually confirm and set the test position so that the position where a foreign object is located does not overlap with the test position. In the case where the position where the foreign object is located overlaps with the test position, the test position must be reset based on user operation, and thus there is a problem of taking time and effort.

[0008] The present invention has been made in view of such problems, and an object thereof is to provide a hardness testing machine and a program that can simplify the setting of the test position.

[0009] Means for Solving the Problems

[0010] The invention according to Technical Solution 1 is achieved to achieve the above object, and is a hardness testing machine that forms an indentation by applying a given test force to the surface of a specimen using an indenter and measures the size of the indentation, thereby measuring the hardness of the specimen. The hardness testing machine is characterized by comprising:

[0011] an image acquisition unit that acquires an image of the surface of the specimen captured by a photographing unit;

[0012] a determination unit that determines an unsuitable area in the image that is not suitable for a hardness test according to given conditions based on the image of the surface of the specimen; and

[0013] a test position setting unit that sets a test position in an area other than the unsuitable area determined by the determination unit.

[0014] The invention according to Technical Solution 2 is characterized in that, in the hardness tester according to Technical Solution 1,

[0015] the hardness tester is provided with a specifying unit that specifies one or more test positions in the specimen based on an image of the surface of the specimen obtained by the image acquisition unit.

[0016] The test position setting unit sets the test positions specified by the specifying unit, and when the test position is included in the unsuitable area, corrects the test position to a position not included in the unsuitable area.

[0017] The invention according to Technical Solution 3 is characterized in that, in the hardness tester according to Technical Solution 2,

[0018] When the specifying unit specifies a test pattern related to the arrangement of the test positions based on a user operation, the specifying unit specifies the multiple test positions based on the test pattern.

[0019] The test position setting unit targets the test positions included in the unsuitable area among the test positions specified by the specifying unit, and corrects the test position to a position not included in the unsuitable area.

[0020] The invention according to Technical Solution 4 is characterized in that, in the hardness tester according to Technical Solution 2 or 3,

[0021] When the test position setting unit corrects the test position included in the unsuitable area to a position not included in the unsuitable area, it corrects it to a position where the distance from a given point, line or plane on the specimen to the test position is the same distance as the original.

[0022] The invention according to Technical Solution 5 is characterized in that, in the hardness tester according to Technical Solution 2,

[0023] When the specifying unit specifies a test pattern related to the arrangement of the test positions based on a user operation, the specifying unit specifies the multiple test positions based on the test pattern.

[0024] When at least any one of the test positions specified by the specifying unit is included in the unsuitable area, the test position setting unit corrects each of the test positions to a position not included in the unsuitable area and capable of maintaining the test pattern.

[0025] The invention according to Technical Solution 6 is characterized in that, in the hardness tester according to any one of Technical Solutions 1 to 5,

[0026] The hardness testing machine is equipped with a binarization unit that binarizes the image of the surface of the specimen obtained by the image acquisition unit based on a given threshold value.

[0027] The determination unit determines, based on the image data binarized by the binarization unit, the area that is below the given threshold value as the unsuitable area.

[0028] The invention according to Technical Solution 7 is a computer-readable storage medium storing a program, and the program causes a computer of the hardness testing machine to function as an image acquisition unit, a determination unit, and a test position setting unit. The hardness testing machine forms an indentation by applying a given test force to the surface of the specimen using an indenter, and measures the size of the indentation to determine the hardness of the specimen.

[0029] The image acquisition unit acquires an image of the surface of the specimen captured by the imaging unit.

[0030] The determination unit determines, based on the image of the surface of the specimen, an unsuitable area in the image that is not suitable for the hardness test according to given conditions.

[0031] The test position setting unit sets a test position in an area other than the unsuitable area determined by the determination unit.

[0032] Advantages of the Invention

[0033] According to the present invention, the setting of the test position can be made simple. Description of the Drawings

[0034] Figure 1 is a side view showing the overall structure of the hardness testing machine according to the present invention.

[0035] Figure 2 is a side view showing the overall structure of the hardness testing machine according to the present invention.

[0036] Figure 3 is a block diagram showing the control structure of the hardness testing machine according to the present invention.

[0037] Figure 4 is a flowchart showing the operation of the hardness testing machine according to the present invention.

[0038] Figure 5 In (a), it is a diagram showing a state where each initially set test position is superimposed on the surface image of the specimen and displayed, and in (b), it is a diagram showing a state where each corrected test position is superimposed on the surface image of the specimen and displayed.

[0039] Figure 6 is a diagram showing a state where each test position is corrected in the manual correction mode. Detailed implementation mode

[0040] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0041] [1. Description of the structure]

[0042] As Figures 1 to 3 shown, the hardness testing machine 1 according to this embodiment is configured to include: a testing machine main body 2 on which each component is arranged; a load arm 3 rotatably supported by the testing machine main body 2; an arm actuator 4 that applies an acting force (test force) to the load arm 3 to make the load arm 3 work; a turntable 8 of the testing machine main body 2 rotatably provided below the load arm 3; a indenter shaft 6 mounted on the turntable 8 and having an indenter 5 at its front end; an objective lens 7 mounted on the turntable 8; a specimen stage 9 disposed opposite to the turntable 8 and on which a specimen S is placed; a photographing unit 10 that photographs the indentation formed on the specimen S on the specimen stage 9; an operation unit 15 for inputting the test force and the assumed hardness of the specimen S; a display unit 16 for displaying an image of the surface of the specimen S and the indentation formed on the surface of the specimen S; and a control unit 100. In addition, in the hardness testing machine 1, the control unit 100 controls the operations of each part.

[0043] The load arm 3 is configured to include an arm main body 31 and a rotation shaft 32 that pivotally supports one end portion 31a of the arm main body 31 on the testing machine main body 2.

[0044] The other end side of the arm main body 31 branches into two branches, a first other end portion 31b and a second other end portion 31c. The first other end portion 31b is formed in a flexible leaf spring shape.

[0045] On the lower surface side of the arm main body 31, a load shaft 33 elastically supported by a coil spring 33a is provided between the lower surface of the arm main body 31 and the testing machine main body 2.

[0046] In addition, the arm main body 31 is provided with an arm displacement detection unit 34 that detects the opening amount between the first other end portion 31b and the second other end portion 31c when the load arm 3 (arm main body 31) works.

[0047] Regarding the arm main body 31, one end portion 31a thereof is pivotally supported on the testing machine main body 2 by the rotation shaft 32, and an arm actuator 4 is connected to the first other end portion 31b, and the arm actuator 4 generates an acting force as a test force for making the load arm 3 work. And the arm main body 31 rotates about the rotation shaft 32 as the arm actuator 4 operates. As the arm main body 31 rotates downward, the load shaft 33 is pressed downward and moves. Then, the load shaft 33 transmits the drive and operation of the arm main body 31 (load arm 3) to the indenter shaft 6 (refer to Figure 1 ).

[0048] The arm displacement detection unit 34 is configured to include a scale ruler with scales engraved at a given interval and a linear encoder that optically reads the scales of the scale ruler. The arm displacement detection unit 34 detects the opening amount (spring displacement amount) between the first other end portion 31b and the second other end portion 31c when the indenter 5 is pressed into the specimen S via the indenter shaft 6 or the like, and outputs an arm displacement signal based on the detected opening amount to the control unit 100. In addition, this opening amount corresponds to the pressing force (test force) for pressing the indenter 5 into the specimen S or the load applied to the specimen S.

[0049] The arm actuator 4 is configured to include: a servo motor 41; a ball screw 43; a timing belt 42 that is installed between the motor shaft 41a of the servo motor 41 and the screw shaft 43a of the ball screw 43; and a fixed jig 44 that is held by the ball screw 43. In addition, the arm actuator 4 is fixed to the first other end portion 31b of the arm main body 31 by the leaf spring 44a of the fixed jig 44, and is thus connected to the load arm 3.

[0050] The servo motor 41 is driven based on a drive control signal input from the control unit 100. The motor shaft 41a of the servo motor 41 rotates by the drive of the servo motor 41. The driving force of the motor shaft 41a is transmitted to the screw shaft 43a of the ball screw 43 via the timing belt 42, causing the ball screw 43 to rotate. The fixed jig 44 moves up and down by the rotational drive of the ball screw 43.

[0051] In this way, the arm actuator 4 moves the fixed jig 44 up and down based on the drive of the servo motor 41, and transmits this drive (driving force) to the first other end portion 31b of the arm main body 31 connected to the fixed jig 44, causing the arm main body 31 (load arm 3) to rotate. In addition, the leaf spring 44a flexes when the arm actuator 4 moves the load arm 3.

[0052] The specimen stage 9 is configured to include: a specimen stage 91 on which the specimen S is placed; an electric stage 92 provided on the lower surface of the specimen stage 91; and a stage lifting unit 93 provided on the lower surface of the electric stage 92.

[0053] The electric stage 92 is driven by a drive mechanism unit (not shown), and can move in a direction (horizontal direction) perpendicular to the indenter shaft 6. The drive mechanism unit is driven according to a control signal output from the control unit 100.

[0054] The stage lifting unit 93 has a threaded portion 93a, and by rotating the threaded portion 93a, the specimen stage 91 can be moved up and down relative to the testing machine main body 2.

[0055] The turntable 8 is configured to include a turntable main body 81 and a rotating shaft 82 that rotatably supports the turntable main body 81 on the testing machine main body 2.

[0056] The turntable main body 81 is provided with an indenter shaft 6, an objective lens 7, and an indenter shaft displacement detection unit 20 that detects the displacement amount of the indenter shaft 6. In addition, the indenter shaft 6 is disposed on the turntable main body 81 via an indenter shaft holding unit 61.

[0057] The turntable main body 81 can switch the configurations of the indenter shaft 6 and the objective lens 7 by rotating about the rotation axis 82.

[0058] The indenter shaft holding unit 61 is configured to include a longitudinal holding member 61a and leaf springs 61b, 61b that extend laterally from the longitudinal holding member 61a. The indenter shaft 6 is elastically supported by the leaf springs 61b, 61b of the indenter shaft holding unit 61 and is disposed perpendicularly to the placement surface of the specimen S on the specimen stage 91, particularly the surface (upper surface) of the specimen placed on the specimen stage 91.

[0059] An indenter 5 is provided at the lower end of the indenter shaft 6 in a replaceable manner. For example, in the case of performing a Vickers hardness test, a square pyramid indenter for Vickers (opposite angle: 136 ± 0.5°) is used as the indenter 5. In the present embodiment, a square pyramid indenter for Vickers is used as the indenter 5.

[0060] As Figure 1 shown, by rotating the turntable 8 (turntable main body 81), the hardness tester 1 switches the indenter shaft 6 to a configuration corresponding to the load shaft 33, and can transmit the force of the action of moving the load shaft 33 downward as the load arm 3 rotates to the indenter shaft 6. Thus, the hardness tester 1 can press the indenter 5 against the specimen S and press it in.

[0061] The objective lens 7 is a lens unit of the microscope unit 11 attached to the photographing unit 10. As Figure 2 shown, by rotating the turntable 8 (turntable main body 81), the hardness tester 1 switches the objective lens 7 to a configuration corresponding to the photographing unit 10, and can perform photographing of the specimen S by the photographing unit 10.

[0062] The indenter shaft displacement detection unit 20 is configured to include a scale engraved with given intervals and a linear encoder that optically reads the scale of the scale. The indenter shaft displacement detection unit 20 detects the displacement amount (i.e., the penetration amount of the indenter 5 pressing into the specimen S, the depth of the indentation) that the indenter shaft 6 moves when forming an indentation on the specimen S, and outputs an indenter shaft displacement signal based on the detected displacement amount to the control unit 100.

[0063] The photographing unit (photographing element) 10 is configured to include a microscope unit 11, a CCD (Charge Coupled Device) camera 10a mounted on the microscope unit 11, and an illumination device (not shown) that irradiates the observation position of the specimen S, and photographs the indentation formed on the surface of the specimen S. Then, the photographing unit 10 (CCD camera 10a) outputs the photographed image of the indentation to the control unit 100.

[0064] The operation unit 15 includes an indicating device such as a keyboard and a mouse, and accepts the input operation of an operator (operator) during the hardness test. For example, the operation unit 15 accepts the input operations of the test force and the assumed hardness of the specimen S estimated by the operator. Further, when the operation unit 15 accepts a given input operation performed by the operator, it generates a given operation signal corresponding to the input operation and outputs it to the control unit 100.

[0065] The display unit 16 is constituted by a display device such as an LCD (Liquid Crystal Display), for example. The display unit 16 displays the set conditions of the hardness test input in the operation unit 15, the results of the hardness test, and the image of the surface of the specimen S or the indentation formed on the surface of the specimen S photographed by the CCD camera 10a.

[0066] As Figure 3 shown, the control unit (image acquisition unit, determination unit, test position setting unit, designation unit, binarization unit) 100 is configured to include a CPU, a RAM, a ROM, etc., and has a function of performing operation control for implementing a given hardness test by executing a given program stored in the ROM. In addition to the given program, the ROM stores, for example, a plurality of test patterns related to the arrangement of test positions used in the multi-point measurement process described later.

[0067] For example, the control unit 100 compares the arm displacement signal input from the arm displacement detection unit 34 with the preset set arm displacement data. Further, the control unit 100 outputs a drive control signal for controlling the drive of the arm actuator 4 (servo motor 41) to the servo motor 41 in order to rotate the load arm 3 so that the indenter 5 acts on the specimen S with a given test force (load).

[0068] In addition, the control unit 100 controls the electric stage 92 to move the specimen stage 9 (specimen stage 91) in the horizontal direction, thereby realizing the test positioning function of determining the position where the indentation is formed on the specimen S.

[0069] In addition, the control unit 100 controls the stage lifting unit 93 to move the sample stage 9 (sample stage 91) in the vertical direction, changing the relative distance between the sample stage 91 and the objective lens 7, thereby realizing the autofocus function of focusing on the surface of the sample S placed on the sample stage 91.

[0070] In addition, the control unit 100 performs given image processing on the image of the indentation input from the imaging unit 10 for analysis, automatically measures the size (dimension) of the indentation, and detects the distance between given feature points. In addition, the control unit 100 calculates the hardness of the sample S based on the detected distance between given feature points of the indentation. That is, the control unit 100 measures the hardness of the sample S according to the size of the indentation (the distance between given feature points) formed by pressing the indenter 5 into the sample S, and calculates the hardness of the sample S based on, for example, the Vickers hardness test.

[0071] [2. Description of the operation]

[0072] Next, with reference to Figure 4 the flowchart of, the multi-point measurement process performed by the hardness tester 1 of the present embodiment will be described.

[0073] As Figure 4 shown, first, the control unit 100 acquires the surface image of the sample S captured by the CCD camera 10a (step S1).

[0074] Next, the control unit 100 determines whether an operation of specifying the test pattern desired by the user has been performed via the operation unit 15 (step S2).

[0075] In the case where it is determined in step S2 that the operation of specifying the test pattern desired by the user has not been performed (step S2: No), the control unit 100 repeatedly performs the determination process of step S2 until the operation of specifying the test pattern desired by the user is performed. On the other hand, in the case where it is determined in step S2 that the operation of specifying the test pattern desired by the user has been performed (step S2: Yes), the control unit 100 sets the test positions based on the specified test pattern (step S3).

[0076] For example, as Figure 5 shown in (a) of, in the surface image IM1 of the sample S, in the case where a test pattern of performing five-point measurement at a given interval in the direction orthogonal to the end face E (the right direction in the figure) starting from a point at a given distance from the end face E of the sample S is specified as the test pattern, the control unit 100 sets the respective test positions P1, P2,..., P5 of the above five points based on this test pattern.

[0077] Next, the control unit 100 determines an unsuitable region NR (e.g., a region containing foreign substances such as graphite) that is unsuitable for the hardness test from the surface image of the specimen S obtained in step S1 (step S4). Specifically, the control unit 100 binarizes the surface image of the specimen S obtained in step S1 based on a given threshold. Then, based on the binarized image data, the control unit 100 determines the region that becomes below the above-mentioned given threshold as the unsuitable region NR (refer to Figure 5 ).

[0078] Next, the control unit 100 determines, for each test position set in step S3, whether there is a test position included in the unsuitable region NR determined in step S4 (step S5).

[0079] When it is determined in step S5 that there is a test position included in the unsuitable region NR (step S5: Yes), the control unit 100 corrects the test position included in the unsuitable region NR (step S6). For example, as shown in (a) of Figure 5 , when the test position P4 is included in the unsuitable region NR, the control unit 100 corrects it to a position that has the same distance from the end face E of the specimen S to the test position P4 and is not included in the unsuitable region NR (e.g., the test position P6 (refer to Figure 5 (b))). Then, the control unit 100 proceeds with the process to step S7.

[0080] In addition, when it is determined in step S5 that there is no test position included in the unsuitable region NR (step S5: No), the control unit 100 skips step S6 and proceeds with the process to step S7.

[0081] Next, the control unit 100 forms indentations in sequence at each test position set in step S3 (wherein, for the test positions determined to be included in the unsuitable region NR, they are the corrected test positions) by controlling the load arm 3, the electric stage 92, etc. (step S7). For example, as shown in (b) of Figure 5 , when the settings of each test position P1, P2, P3, P6, P5 are made, for example, indentations are formed in sequence from the test position P1 to the test positions P2, P3, P6, P5.

[0082] Next, the control unit 100 obtains the surface image of the specimen S after the indentations are formed, which is captured by the CCD camera 10a (step S8).

[0083] Next, the control unit 100 calculates the hardness value of the specimen S after indentation formation based on the surface image of the specimen S obtained in step S8 (step S9). Specifically, the control unit 100 analyzes the surface image of the specimen S, measures the diagonal length of the indentation formed on the surface of the specimen S, and calculates the hardness value of the specimen S based on the measured diagonal length. Then, the control unit 100 ends the multi-point measurement process.

[0084] As described above, the hardness testing machine 1 according to the present embodiment includes: an image acquisition unit (control unit 100) that acquires an image (surface image) of the surface of the specimen S captured by the imaging unit (imaging unit 10); a determination unit (control unit 100) that determines an unsuitable area NR in the image that is not suitable for the hardness test according to given conditions based on the image of the surface of the specimen S; and a test position setting unit (control unit 100) that sets a test position in an area other than the unsuitable area NR determined by the determination unit.

[0085] Therefore, according to the hardness testing machine 1 according to the present embodiment, when setting the test position, it is possible to save the time and effort for the user to visually confirm whether the position of the foreign object overlaps with the test position, so that the setting of the test position can be simplified.

[0086] In addition, the hardness testing machine 1 of the present embodiment includes a specifying unit (control unit 100) that specifies one or more test positions in the specimen S based on the surface image of the specimen S acquired by the image acquisition unit. The test position setting unit sets the test positions specified by the specifying unit, and when the test position is included in the unsuitable area, corrects the test position to a position not included in the unsuitable area NR.

[0087] Therefore, according to the hardness testing machine 1 according to the present embodiment, when the test position set once is included in the unsuitable area NR, it is possible to save the time and effort for the user to reset the test position to a position not included in the unsuitable area NR, so that the setting of the test position can be simplified.

[0088] In addition, according to the hardness testing machine 1 according to the present embodiment, when a test pattern related to the arrangement of test positions is specified based on a user operation, a plurality of test positions are specified based on the test pattern, and the test positions included in the unsuitable area NR among the specified test positions are used as targets, and the test positions are corrected to positions not included in the unsuitable area NR. Therefore, for example, when there are test positions included in the unsuitable area NR during multi-point measurement under a test pattern desired by the user, the test positions can be appropriately corrected, so that the multi-point measurement can be smoothly performed.

[0089] In addition, according to the hardness testing machine 1 according to the present embodiment, when the test position included in the unsuitable area NR is corrected to a position not included in the unsuitable area NR, it is corrected to a position where the distance from the reference surface E of the specimen S to the test position is the same, so that measurement at a sub-optimal position can be performed.

[0090] In addition, the hardness testing machine 1 according to the present embodiment includes a binarization unit (control unit 100) that binarizes the image of the surface of the specimen S obtained by the image acquisition unit based on a given threshold, and the determination unit determines the area that becomes below the given threshold as the unsuitable area NR based on the image data binarized by the binarization unit. Therefore, the determination of the unsuitable area NR can be easily performed.

[0091] As described above, the embodiments according to the present invention have been specifically described, but the present invention is not limited to the above embodiments and can be modified within the scope without departing from the gist thereof.

[0092] For example, in the above embodiment, as shown in (a) of Figure 5 and (b) of Figure 5 , taking the test position P4 included in the unsuitable area NR among the test positions P1 to P5 set by the control unit 100 as an example, the test position P4 is corrected to a position P6 not included in the unsuitable area NR, but it is not limited thereto. For example, when the test position P4 among the test positions P1 to P5 is included in the unsuitable area NR as described above, the test positions P1 to P5 may also be corrected to positions that are not included in the unsuitable area NR and can maintain the initially specified test pattern.

[0093] In addition, in the above-described embodiment, since the test positions are set based on a sample pattern obtained by starting from a point at a given distance from the end face E of the sample S and performing five-point measurement in a direction orthogonal to the end face E, when correcting a test position included in the unsuitable region NR to a position not included in the unsuitable region NR, with the end face E of the sample S as a reference, it is corrected to a position where the distance from this reference to the test position is the same. However, for example, in the case of the shaft portion of a gear, when setting a plurality of test positions based on the axis, when correcting a test position included in the unsuitable region NR to a position not included in the unsuitable region NR, it is corrected to a position where, with the axis of the gear as a reference, the distance from this reference to the test position is the same. In addition, for the tooth portion of a gear, when setting a plurality of test positions based on the axis, when correcting a test position included in the unsuitable region NR to a position not included in the unsuitable region NR, in this tooth portion, it is corrected to a position where, with the axis of the gear as a reference, the distance from this reference to the test position is the same. In addition, for example, in the case of setting a plurality of test positions based on the welded portion (boundary line) when two base materials are welded, when correcting a test position included in the unsuitable region NR to a position not included in the unsuitable region NR, it is corrected to a position where, with this welded portion (boundary line) as a reference, the distance from this reference to the test position is the same.

[0094] In addition, in the above-described embodiment, the test positions P1 to P5 are temporarily set based on a test pattern specified by a user's operation, and the test position P4 included in the unsuitable region NR is automatically corrected to the test position P6. However, for example, in the case of automatically setting the test positions without going through the user's operation, the test positions can also be set from the beginning in a region not included in the unsuitable region NR.

[0095] In addition, in the above-described embodiment, the unsuitable region NR is determined by binarizing the image of the surface of the sample S based on a given threshold. However, as long as the unsuitable region NR containing foreign substances such as graphite can be determined, the above determination method is not limited. For example, a template image obtained by photographing a region containing foreign substances can be stored in advance, and the unsuitable region NR can be determined by performing a matching process between the surface image of the sample S to be measured and the template image.

[0096] In addition, in the above-described embodiment, in the multi-point measurement process (refer to Figure 4)When it is determined that there is a test position included in the unsuitable area NR, the control unit 100 automatically corrects the test position. However, in this case, it can also be configured such that the user can manually correct the test position. Specifically, when it is determined that there is a test position included in the unsuitable area NR, the control unit 100 notifies, for example, via the display unit 16 the meaning that there is a test position included in the unsuitable area NR. Thereafter, when a transfer instruction to the manual correction mode in which the test position can be manually corrected is input via the operation unit 15, as Figure 6 shown, the control unit 100 overlaps a grid (raster) L on the surface image IM2 of the specimen S and displays it on the display unit 16. Then, by inputting via the operation unit 15 the specification of the intersection point of the above grid L, the test position P can be corrected to the intersection point where the specification is made. In addition, it can also be configured such that after the control unit 100 automatically corrects the test position, the correction of the test position in the above manual correction mode can be performed. In addition, for example, when the specimen S is a cylindrical workpiece, concentric circles are overlapped instead of the grid L and displayed on the display unit 16. Then, it can also be configured such that by inputting via the operation unit 15 the specification of the intersection point between the above concentric circle and the normal line at the angle desired by the user, the test position can be corrected to the intersection point where the specification is made.

[0097] In addition, in the above embodiment, as the hardness tester 1, a Vickers hardness tester in which the planar shape of the indenter 5 is formed as a rectangle is illustrated as an example, but it is not limited thereto. That is, as long as it is a hardness tester that applies a given test force to the surface of the specimen S through the indenter 5 to form an indentation and measures the size of the indentation, thereby determining the hardness of the specimen S, it can be any hardness tester. For example, it can also be a Knoop hardness tester having an indenter based on a diamond square hammer and having the planar shape of the indenter formed as a rectangle in the same manner as the Vickers hardness tester, or a Brinell hardness tester having the shape of the indenter formed as a sphere.

[0098] In addition, each mode shown in the present application can also be grasped as a method, a program, etc. Regarding the category of the method or program, the “unit” shown in the category of the device is appropriately replaced with, for example, “process” or “step”. In addition, the order of the processes or steps is not limited to the order directly shown in the present application, and the order can be changed, or a part of the processes can be aggregated or a part can be executed at any time.

[0099] In addition, regarding the detailed structure of each device constituting the hardness tester and the detailed operation of each device, it can also be appropriately changed within the scope not departing from the gist of the present invention.

[0100] Symbol description

[0101] 1 Hardness tester

[0102] 2 Testing machine main body

[0103] 3 Load arm

[0104] 4 Arm actuator

[0105] 5 Indenter

[0106] 6 Indenter shaft

[0107] 7 Objective lens

[0108] 8 Turntable

[0109] 9 Specimen stage

[0110] 10 Photographing unit (photographing element)

[0111] 15 Operation unit

[0112] 16 Display unit

[0113] 20 Indenter shaft displacement detection unit

[0114] 100 Control unit (image acquisition unit, determination unit, test position setting unit, designation unit, binarization unit)

[0115] S Specimen

Claims

1. A hardness testing machine that forms an indentation by applying a given test force to the surface of a specimen using an indenter and measures the size of the indentation to determine the hardness of the specimen, wherein the hardness testing machine is characterized by comprising: an image acquisition unit that acquires an image of the surface of the specimen captured by a photographing unit; a determination unit that determines an unsuitable area within the image that is not suitable for the hardness test according to given conditions based on the image of the surface of the specimen; and a test position setting unit that sets a test position in an area other than the unsuitable area determined by the determination unit, the hardness testing machine has a manual correction mode in which a user manually corrects the test position via an operation unit, the hardness testing machine has a control unit that, in the case of the manual correction mode, overlays grids or concentric circles on the image of the surface of the specimen and displays the same on a display unit, the test position setting unit, in the case of the manual correction mode, sets the test position as the test position designated by the operation unit.

2. The hardness testing machine according to claim 1, wherein the hardness testing machine has a designation unit that designates one or more test positions in the specimen based on the image of the surface of the specimen acquired by the image acquisition unit, the test position setting unit sets the test positions designated by the designation unit, and in the case where a test position is included in the unsuitable area, corrects the test position to a position not included in the unsuitable area.

3. The hardness testing machine according to claim 2, wherein when the designation unit designates a test pattern related to the arrangement of the test positions based on a user operation, the designation unit designates the plurality of test positions based on the test pattern, the test position setting unit targets the test positions included in the unsuitable area among the test positions designated by the designation unit and corrects the test position to a position not included in the unsuitable area.

4. The hardness testing machine according to claim 2 or 3, wherein when the test position setting unit corrects a test position included in the unsuitable area to a position not included in the unsuitable area, it corrects the position to a position at the same distance from a given point, line, or plane on the specimen as the distance from the reference to the test position.

5. The hardness testing machine according to claim 2, wherein when the designation unit designates a test pattern related to the arrangement of the test positions based on a user operation, the designation unit designates the plurality of test positions based on the test pattern, when at least any one of the test positions designated by the designation unit is included in the unsuitable area, the test position setting unit corrects each of the test positions to a position not included in the unsuitable area and capable of maintaining the test pattern.

6. The hardness testing machine according to any one of claims 1 to 3, wherein The hardness testing machine is equipped with a binarization unit that binarizes an image of the surface of the specimen obtained by the image acquisition unit based on a given threshold value. The determination unit determines, based on the image data binarized by the binarization unit, the area that is below the given threshold value as the unsuitable area.

7. A computer-readable storage medium, characterized in that, This storage medium stores a program. The program causes a computer of the hardness testing machine to function as an image acquisition unit, a determination unit, and a test position setting unit. The hardness testing machine forms an indentation by applying a given test force to the surface of the specimen using an indenter and measures the size of the indentation, thereby measuring the hardness of the specimen. The image acquisition unit acquires an image of the surface of the specimen captured by the imaging unit. The determination unit determines, based on the image of the surface of the specimen, an unsuitable area within the image that is not suitable for the hardness test according to given conditions. The test position setting unit sets a test position in an area other than the unsuitable area determined by the determination unit. The program includes a manual correction mode in which the user manually corrects the test position via the operation unit. The program causes the computer of the hardness testing machine to function as a control unit. In the case of the manual correction mode, the control unit overlays grids or concentric circles on the image of the surface of the specimen and displays it on the display unit. In the case of the manual correction mode, the test position setting unit sets the test position as the test position specified by the operation unit.

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