JP5132403B2 - Apparatus, method, and program for measuring shape of spiral spring - Google Patents

Description

  The present invention relates to a technique for measuring the shape of an object using image processing. In particular, the present invention relates to a technique for measuring the shape of a spiral spring using image processing. The spiral spring here means a spring that spirally extends from the inner hook to the outer hook when viewed in plan.

  Patent Document 1 discloses a technique for measuring the shape of an object using image processing. In this technique, a pre-registered measurement target region is extracted from a captured image obtained by photographing an object that is a measurement target, and the dimensions of each part of the object are measured using the extracted measurement target region image. When extracting the measurement target area, the measurement target area of the reference image obtained by photographing the reference object is used to correct the measurement target area by pattern matching.

Japanese Patent Laid-Open No. 11-334244

The technique of Patent Document 1 can also be applied to shape measurement of a spiral spring. In measuring the shape of the spiral spring, it is mainly necessary to measure the position and shape of the inner hook and the outer hook. Therefore, when using the technique of Patent Document 1, it is necessary to register the above-described measurement target region in accordance with the positions of the inner hook and the outer hook.
However, in the case of a spiral spring, its shape changes variously according to characteristics such as a required spring constant. Therefore, in order to use the technique of Patent Document 1, it is necessary to individually set the measurement target areas according to the shape of the spiral spring. Further, in the case of a spiral spring, even if the same type of spiral spring is used, for example, the positions of the outer hooks and the like are relatively likely to vary, and individual differences are likely to occur in their shapes. For this reason, there are cases where images of the inner hook and the outer hook cannot be extracted in the measurement target region set in advance.
In view of the above problems, the present invention provides a technique capable of correctly specifying the positions of the inner hook and the outer hook from a captured image of a spiral spring.

  The present invention is embodied in a shape measuring device that measures the shape of a spiral spring that spirally extends from an inner hook to an outer hook, and includes an image input unit that inputs a photographed image of the spiral spring; Image conversion means for creating a polar coordinate image obtained by converting the photographed image into polar coordinates, and using the polar coordinate image, an inner hook position where an inner hook is photographed and / or an outer hook in the photographed image is photographed. A hook position specifying means for specifying the outer hook position in the captured image is provided.

In this shape measuring apparatus, polar coordinate conversion is performed on a captured image of a spiral spring to create a polar coordinate image. In the polar coordinate image, along the radial axis, the inner hook, the wire winding portion, and the outer hook are separated from each other. As a result, the positions of the inner hook and the outer hook can be accurately specified. The inner hook and outer hook positions specified on the polar coordinate image can be converted into the inner hook and outer hook positions in the photographed image by performing inverse conversion to orthogonal coordinates.
According to this shape measuring apparatus, the positions of the inner hook and the outer hook can be correctly specified from the captured image of the spiral spring, and the shape measurement of the spiral spring can be performed correctly.

In the above-described shape measuring apparatus, the hook position specifying means creates an r-direction histogram in which each pixel value of the polar coordinate image is added for each position in the radial axis direction, and using the r-direction histogram, the inner hook position and / or the outer hook position is generated. It is preferable to specify the hook position.
When the r-direction histogram as described above is used, the inner hook position and the outer hook position can be accurately and easily specified.

In the shape measuring apparatus according to the present invention, the inner hook region and / or the outer hook in which the inner hook is photographed in the photographed image is photographed using the inner hook position and / or the outer hook position. It is preferable to further include hook area specifying means for specifying the outer hook area.
According to this device, the shooting area of the inner hook and the outer hook is extracted from the captured image of the spiral spring, and the shape of the inner hook and the outer hook, or the entire shape of the spiral spring based on the inner hook and the outer hook is accurately measured. can do.

The hook area specifying means includes an r-direction histogram obtained by adding each pixel value of the polar coordinate image for each position in the radial axis direction, and a θ-direction histogram obtained by adding each pixel value of the polar coordinate image for each position in the angle axis direction. It is preferable that the inner hook region and / or the outer hook region is specified using the r-direction histogram and the θ-direction histogram.
By using the r-direction histogram and the θ-direction histogram as described above, the inner hook region and the outer hook region can be specified accurately and easily.

Preferably, the hook area specifying means specifies the boundary position in the radial direction of the outer hook area using the r-direction histogram, and specifies the boundary position in the circumferential direction of the outer hook area using the θ-direction histogram. .
According to this method, the outer hook region can be specified accurately and easily.

The above hook area specifying means sequentially extracts lines parallel to the radial axis passing through the inner hook of the polar coordinate image, and adds each pixel value on the extracted line for each position in the radial axis direction. It is preferable that the inner hook region is specified using the accumulated histogram.
By using the cumulative histogram as described above, for example, even when the inner hook overlaps the origin of the polar coordinate conversion, the inner hook region can be specified accurately.

The image conversion means described above preferably calculates the center of gravity of the spiral spring image captured in the captured image and performs polar coordinate conversion around the center of gravity.
According to this method, the positions of the inner hook and the outer hook can be correctly specified regardless of the position of the spiral spring photographed in the photographed image.

The shape measuring apparatus of the present invention preferably includes a first winding direction discriminating unit that discriminates the winding direction of the spiral spring photographed in the photographed image. The first winding direction discriminating means preferably discriminates the winding direction of the spiral spring using the cumulative histogram described above.
The shape of the cumulative histogram described above changes symmetrically according to the winding direction of the spiral spring photographed in the photographed image. Therefore, by using this feature of the cumulative histogram, it is possible to determine the winding direction of the spiral spring photographed in the photographed image. By discriminating the winding direction of the spiral spring, it is possible to prevent the positions of the inner hook and the outer hook from being specified incorrectly.

The shape measuring apparatus of the present invention preferably includes a second winding direction discriminating unit that discriminates the winding direction of the spiral spring photographed in the photographed image. The second winding direction determining means preferably determines the winding direction of the spiral spring by dividing the photographed image by a straight line along the inner hook and comparing the two divided areas.
At the base end portion of the inner hook, the strand of the spiral spring is bent in one direction depending on the winding direction. Therefore, when the captured image is divided by a straight line along the inner hook, the base end portion of the inner hook exists in one region, and the base end portion of the inner hook does not exist in the other region. Therefore, the winding direction of the spiral spring photographed in the photographed image can be determined by comparing the pixel values of the two divided regions. By discriminating the winding direction of the spiral spring, it is possible to prevent the positions of the inner hook and the outer hook from being specified incorrectly.

The present invention is also embodied in a shape measuring method for measuring the shape of a spiral spring. This shape measuring method includes an image input process for inputting a captured image obtained by photographing a spiral spring to a computer, an image conversion process for creating a polar coordinate image obtained by converting the captured image into a polar coordinate, and an inner hook using the polar coordinate image. A hook position specifying process is performed for specifying in the captured image the inner hook position where the image is photographed and / or the outer hook position where the outer hook in the photographed image is photographed. In this hook position specifying process, an r-direction histogram is created by adding each pixel value of the polar coordinate image for each position in the radial axis direction, and the inner hook position and / or the outer hook position is specified using the r-direction histogram. .
Also by this method, the positions of the inner hook and the outer hook can be correctly specified from the captured image of the spiral spring, and the shape of the spiral spring can be correctly measured.

The present invention is further embodied in a program for measuring the shape of a spiral spring. This program uses an image input process for inputting a captured image obtained by photographing a spiral spring to a computer, an image conversion process for creating a polar coordinate image obtained by converting the captured image into a polar coordinate, and an inner hook using the polar coordinate image. A hook position specifying process is performed to specify in the photographed image the inner hook position that has been photographed and / or the outer hook position in which the outer hook in the photographed image has been photographed. In this hook position specifying process, an r-direction histogram is created by adding each pixel value of the polar coordinate image for each position in the radial axis direction, and the inner hook position and / or the outer hook position is specified using the r-direction histogram. .
With this program, the position of the inner hook and the outer hook can be correctly specified from the captured image of the spiral spring using a computer, and the shape of the spiral spring can be correctly measured.

  According to the present invention, it is possible to correctly specify the position where the inner hook and the outer hook are photographed from the image obtained by photographing the spiral spring, and to correctly measure the shape of the spiral spring.

Preferred embodiments for carrying out the present invention will be listed.
(Mode 1) The shape measuring apparatus can classify the spiral spring into a first type and a second type using an r-direction histogram. Here, the first type means that the inner hook does not overlap the center of gravity of the spiral spring, and the second type means that the inner hook overlaps the center of gravity of the spiral spring.
(Mode 2) The shape measuring apparatus can extract the feature points of the inner hook or the outer hook from the captured image of the spiral spring by the following procedures (1) to (4).
(1) The contour line of the image of the inner hook or the outer hook is extracted from the inner hook region or the outer hook region specified in the captured image of the spiral spring.
(2) Create an outline coordinate series that represents the extracted outline by coordinate point groups, and extract a plurality of partial outline series from the outline coordinate series.
(3) A similarity or distance measure is calculated for the extracted partial outline series.
(4) A feature point is specified on the contour line of the inner hook or the outer hook using the calculated similarity or distance scale.
(Embodiment 3) The shape measuring apparatus can identify the inner contour line series and the outer contour line series from the contour coordinate series of the inner hook or the outer hook, using the feature points calculated in the second aspect.
(Form 4) The shape measuring apparatus can circularly approximate at least a part of the inner contour line series and the outer contour line series specified in the third form.
(Mode 5) The shape measuring apparatus is configured using a computer. The computer is configured to execute each process by its hardware and stored software (program).
(Mode 6) The shape measuring apparatus includes a camera that captures a spiral spring and creates image data thereof.
(Mode 7) The shape measuring apparatus can binarize the captured image.

Embodiments embodying the present invention will be described with reference to the drawings. FIG. 1 shows a shape measuring apparatus 10 of this embodiment. The shape measuring device 10 is a device that measures the dimensions of each part of the spiral spring 30.
As shown in FIG. 1, the shape measuring apparatus 10 includes a stage 12, an illuminator 14 disposed on the stage 12, a CCD camera 16 fixed to the stage 12, and a communication line 18 connected to the CCD camera 16. And a display 20 connected to the computer 22.
The illuminator 14 is a surface light source, and a spiral spring 30 is placed on the light emitting surface thereof. The CCD camera 16 is disposed on the illuminator 14 and photographs the spiral spring 30 placed on the illuminator 14. That is, the spiral spring 30 is illuminated from below by the illuminator 14, and the transmitted light (shadow of the spiral spring 30) of the illuminator 14 is photographed by the CCD camera 16. The illuminator 14 is not limited to transmitted illumination as in the present embodiment, and may illuminate the spiral spring 30 from above. In this case, it is preferable to use a plurality of illuminators or ring-type illuminators so that the spiral spring 30 is illuminated uniformly from the entire circumferential direction.
Image data captured by the CCD camera 16 is input to the computer 22 via the communication line 18. The computer 22 stores a program for executing a shape measurement process described later. The computer 22 processes image data of a photographed image photographed by the CCD camera 16 and calculates the dimensions of each part of the spiral spring 30. The computer 22 displays the calculated dimensions of each part of the spiral spring 30 on the display 20.

  FIG. 2 is a flowchart showing a flow of measuring the shape of the spiral spring 30 by the shape measuring apparatus 10. FIG. 3 is a flowchart showing the flow of the hook area specifying process in step S14 shown in the flowchart of FIG. The shape measuring apparatus 10 measures the dimensional values of each part of the spiral spring 30 through the processes and processes shown in FIGS. 2 and 3. FIG. 4 shows locations where the shape measuring apparatus 10 measures dimensions. As shown in FIG. 4, the shape measuring apparatus 10 includes (1) an inner diameter Din of the spiral spring, (2) a free angle θf, (3) a hook radius HR, (4) an outer hook length Loh, and (5) an inner hook. Measure nine dimensions: length Lih, (6) outer hook radius of curvature Roh, (7) inner hook radius of curvature Rih, (8) outer hook angle θmt, and (9) distance Dtip from inner hook tip. Can do. The flow of measuring the shape of the spiral spring 30 by the shape measuring device 10 will be described below with reference to the flowcharts shown in FIGS.

First, in step S <b> 12 of FIG. 2, the spiral spring 30 is photographed by the CCD camera 16. 5 and 6 illustrate captured images 100 of two types of spiral springs 30. FIG. Here, when photographing the spiral spring 30, the spiral spring 30 is arranged so as to be clockwise when viewed from above. Moreover, it arrange | positions so that the inner hook 32 may face upwards. An image 100 taken by the CCD camera 16 is input to the computer 22.
Both of the two types of spiral springs 30 shown in FIGS. 5 and 6 extend from the inner hook 32 to the outer hook 34 in a spiral shape. However, these two types of spiral springs 30 have a significant difference in the shape of the inner hook 32. That is, the spiral spring 30 shown in FIG. 5 does not have its inner hook 32 overlapped with the center of gravity G of the spiral spring 30, but the spiral spring 30 shown in FIG. 6 has its inner hook 32 overlapped with the center of gravity G of the spiral spring 30. Yes. In this specification, the spiral spring 30 illustrated in FIG. 5 is referred to as a first type, and the spiral spring 30 illustrated in FIG. 6 is referred to as a second type. The shape measuring apparatus 10 can measure the shapes of the spiral springs 30 of both the first type and the second type. As will be described in detail later, the shape measuring apparatus 10 determines whether the spiral spring 30 to be measured is the first type or the second type, and executes different processes for each type for some processes. In addition, when there is no description in particular distinguished, a common process shall be performed by 1st type and 2nd type.
The photographed image 100 is a gray scale image having a gray scale value GS (x, y) for each pixel (x, y). Here, various processes for removing noise may be performed on the captured image 100 as necessary.

Next, in step S14 of FIG. 2, the inner hook area where the inner hook 32 is photographed and the outer hook area where the outer hook 34 is photographed are identified from the photographed image 100 photographed in step S12. . The inner / outer hook specifying process will be described with reference to the flowchart shown in FIG. The processing from step S14 to step S38 is executed by the computer 22.
First, in step S112 in FIG. 3, a polar coordinate image is created from the captured image 100 obtained in step S12. FIG. 7A shows a polar coordinate image of the first type spiral spring 30 (see FIG. 5). FIG. 8A shows a polar coordinate image of the second type spiral spring 30 (see FIG. 6). A polar coordinate image can be created by obtaining the center of gravity G (cx, cy) of the image of the spiral spring 30 as a temporary center and then using the following conversion formula. Note that Polar (θ, R) indicates a gray scale value in the polar coordinate image.

  Next, in step S114, an r-direction histogram Hr (r) is created using the polar coordinate image created in step S112. The r-direction histogram Hr (r) is an average obtained by adding the gray scale values Polar (θ, R) of the polar coordinate image in the θ-axis direction. FIG. 7B shows an r-direction histogram of the first type spiral spring 30 (see FIG. 5). FIG. 8B shows an r-direction histogram of the second type spiral spring 30 (see FIG. 6). The r-direction histogram value Hr (r) is calculated by the following equation. Note that THe in the following equation is a threshold value for removing noise.

  Next, in step S116, the inner hook shape 32 is identified. That is, it is determined whether the spiral spring 30 to be measured is the first type or the second type. For this process, the r-direction histogram created in step S114 is used. As is clear from comparison between FIG. 7B and FIG. 8B, the center of gravity G is not located on the inner hook 32 in the first type spiral spring 30 (see FIG. 5). The value near the θ-axis (r = 0) becomes small. On the other hand, in the second type spiral spring 30, since the center of gravity G is located on the inner hook 32 (see FIG. 6), the value is large in the vicinity of the θ axis (r = 0) in the r-direction histogram. Therefore, in the process of step S116, attention is paid to the r-direction histogram value Hr (r) up to 0 ≦ r ≦ 15. When the minimum r-direction histogram value Hr (r) in the range is equal to or smaller than a predetermined determination value, the first type is determined, and the minimum r-direction histogram value Hr (r) in the range exceeds the determination value. Sometimes it is determined as the second type.

Next, in step S118, the positions (coordinates) of the inner hook 32 and the outer hook 34 are detected. In this process, an r-direction histogram is used. In this processing, different processing is executed for each type of spiral spring 30 as in the following (1) and (2).
(1) For the first type (outer hook position)
As shown in FIG. 7A, the polar coordinate (θout, Rout) farthest from the center of gravity G in the polar coordinate image of the spiral spring 30 is detected as the position of the outer hook 34 in the polar coordinate image. The polar coordinates (θout, Rout) of the outer hook 34 are specified as follows. First, the target coordinate r is sequentially subtracted from the maximum value (right end of the polar coordinate image), and the r coordinate when the r-direction histogram value Hr (r) exceeds a predetermined threshold value TH (not shown) is determined as an outer hook. The r coordinate Rout of 34 is assumed. Next, paying attention to one line of r = Rout in the polar coordinate image, the θ coordinate on which the gray scale value Polar (θ, Rout) is minimum is set as the θ coordinate θout of the outer hook 34. The calculated polar coordinates (θout, Rout) of the outer hook 34 are converted into orthogonal coordinates (xout, yout) of the outer hook 34.

(Inner hook position)
As shown in FIG. 7A, the polar coordinate (θin, Rin) closest to the center of gravity G in the polar coordinate image of the spiral spring 30 is detected as the position of the position of the inner hook 32 in the polar coordinate image. The polar coordinates (θin, Rin) of the inner hook 32 are specified as follows. First, the attention coordinate r is sequentially added from r = 0 (the left end of the polar coordinate image), and the r coordinate rthc when the r-direction histogram value Hr (r) exceeds a predetermined threshold value THc is specified. Next, the attention coordinate r is sequentially subtracted from r = rthc, and the r coordinate rc0 at which the r-direction histogram value Hr (r) becomes zero is specified. The r coordinate Rin of the inner hook 32 is specified as Rin = rc0 + 1 as the previous r coordinate where the r-direction histogram value Hr (r) becomes zero. Next, paying attention to one line of r = Rin in the polar coordinate image, the θ coordinate at which the gray scale value Polar (θ, Rin) is minimum on the line is set as the θ coordinate θin of the inner hook 32. The calculated polar coordinates (θin, Rin) of the inner hook 32 are converted into orthogonal coordinates (xin, yin) of the inner hook 32.

(2) For the second type (outer hook position)
As shown in FIG. 8A, the polar coordinate (θout, Rout) farthest from the center of gravity G in the polar coordinate image of the spiral spring 30 is detected as the position of the outer hook 34 in the polar coordinate image. The polar coordinates (θout, Rout) and the orthogonal coordinates (xout, yout) of the outer hook 34 are specified in the same manner as in the first type.
(Inner hook position)
As shown in FIG. 8A, in the polar coordinate image of the spiral spring 30, the polar coordinates (θin, Rin) of the constricted portion of the polar coordinate image are detected as positions in the polar coordinate image of the inner hook 32. First, the attention coordinate r is sequentially subtracted from r = Rout, and the r coordinate when the r-direction histogram value Hr (r) exceeds a predetermined threshold value THd is specified as the provisional outer diameter Rd of the spiral spring 30. To do. Next, paying attention to the r-direction histogram value Hr (r) in the range of 15 ≦ r <Rd, the minimum value hm of the r-direction histogram value Hr (r) and the r coordinate Rm that gives the minimum value hm are temporarily It is specified as the r coordinate of the hook. FIG. 9 shows an enlarged r direction histogram in the vicinity of the r coordinate Rm. As shown in FIG. 9, the r coordinate is then added in order from r = Rm to r = Rm + Δ starting from the temporary inner hook coordinate Rm, and the r coordinate whose r-direction histogram value Hr (r) exceeds hm + δ. Specify rb. Further, the r coordinate is subtracted sequentially from r = Rm to r = Rm−Δ, and the r coordinate ra in which the r-direction histogram value Hr (r) exceeds hm + δ is specified. Then, the median value (ra + rb) / 2 of the r coordinate ra and the r coordinate rb is set as the r coordinate Rin of the inner hook 32. As for the θ coordinate θin of the inner hook 32, the θ coordinate at which the gray scale value Polar (θ, Rin) is minimum is set as the θ coordinate θin of the inner hook 32, as in the first type. The calculated polar coordinates (θin, Rin) of the inner hook 32 are converted into orthogonal coordinates (xin, yin) of the inner hook 32.

Next, in steps S120 and S122 in FIG. 3, the outer hook area 104 shown in FIG. 10 is specified. The outer hook region 104 is a region where the outer hook 34 is photographed in the photographed image 100 of the spiral spring 30. The shape measuring apparatus 10 of the present embodiment identifies the outer hook region 104 from the captured image 100 of the spiral spring 30 by the process described below. Note that the processes in steps S120 and S122 are the same regardless of the type of the spiral spring 30.
First, in step S120, the boundary radius Rcut of the outer hook region 104 shown in FIG. 10 is specified. This boundary radius Rcut determines the boundary inside the outer hook region 104 in the radial direction. The boundary radius Rcut is specified as follows. As shown in FIGS. 11A and 11B, the target coordinate r is sequentially subtracted from the maximum value (right end of the polar coordinate image), and the r-direction histogram value Hr (r) is set to a predetermined threshold value THr / 2. The r coordinate when exceeding is set as the r coordinate Rcut of the outer hook 34.

  Next, in step S122, a boundary upper limit angle θe and a boundary lower limit angle θs that are boundaries in the circumferential direction of the outer hook region 104 shown in FIG. 10 are specified. These boundary upper limit angle θe and boundary lower limit angle θs determine the boundary in the circumferential direction of the outer hook region 104. The boundary upper limit angle θe and the boundary lower limit angle θs are specified as follows. First, a θ-direction histogram Ho (θ) is created for a range in which the r coordinate of the polar coordinate image shown in FIG. 11A is larger than the boundary radius Rcut. FIG. 12 shows a θ-direction histogram Ho (θ). The θ-direction histogram Ho (θ) is obtained by adding the gray scale value Polar (θ, r) along the r-axis for each θ coordinate. The θ direction histogram Ho (θ) is calculated by the following equation. Note that THo in the following equation is a threshold value for removing noise.

In the θ direction histogram Ho (θ) shown in FIG. 12, the attention coordinate θ is increased from θin, which is the θ coordinate of the inner hook 32 specified in step S118, to θin + θ1 (θ1: predetermined angle value), The θ coordinate θoe at which the histogram Ho (θ) is zero is specified (Ho (θoe) = 0). Further, the attention coordinate θ is subtracted from θin to θin−θ1, and the θ coordinate θos at which the θ direction histogram Ho (θ) becomes zero is specified (Ho (θos) = 0). The boundary upper limit angle θe and the boundary lower limit angle θs of the outer hook region 104 give a margin width θ2 (θ2 <θ1) to the θ coordinates θoe and θos specified here, the boundary upper limit angle θe = θoe + θ2, and the boundary lower limit angle θs = θos. It is defined as -θ2.
As described above, the boundary radius Rcut, the boundary upper limit angle θe, and the boundary lower limit angle θs that define the outer hook region 104 are determined, and the outer hook region 104 is specified. With these boundary values Rcut, θe, and θs, an outer hook image 114 that shows only the outer hook 34 as shown in FIG. 13 can be obtained from the captured image 100 of the spiral spring 30.

  Next, in step S124 of FIG. 3, the inner hook area 102 shown in FIG. 14 is specified. The inner hook region 102 is a region where the inner hook 32 is photographed in the photographed image 100 of the spiral spring 30. The shape measuring apparatus 10 of the present embodiment identifies the inner hook region 102 from the captured image 100 of the spiral spring 30 by the process described below. Note that part of the processing of step S124 differs depending on the type of the spiral spring 30.

(1) First Type As shown in FIG. 15, the inner hook area 102 is a rectangular area on the polar coordinate image. Therefore, by determining the boundary line r = rc in the r-axis (radial axis) direction and the boundary lines θ = θis and θ = θie in the θ-axis (angle axis) direction shown in FIG. The hook area 102 can be specified.
The determination of the boundary lines r = rc, θ = θis, θ = θie is based on the θ coordinate θin of the inner hook 32 calculated in step S118, and the angle range θin ≦ θ ≦ θin + k (k = 0, 1, 2, ..)) Is used as a cumulative histogram Hin (r, k) obtained by accumulating the gray scale value Polar (θ, r) for each r coordinate. The cumulative histogram Hin (r, k) can be calculated by the following equation.

FIGS. 16A and 16B illustrate the cumulative histogram Hin (r, k). FIG. 16A shows a cumulative histogram Hin (r, 0) for k = 0. Hin (r, 0) is equal to Polar (θin, r). FIG. 16B shows a cumulative histogram Hin (r, k). Thus, a plurality of peaks appear in the cumulative histogram Hin (r, k) according to the number of turns of the spiral spring 30. Of these, the peak at the left end indicates the inner hook 32, and the peak next to it indicates a strand outside the inner hook 32. Therefore, when the right end point of the peak indicating the inner hook 32 is ak and the left end point of the peak indicating one outer strand is bk, the radial boundary line r = rc of the inner hook region 102 is expressed as ak <rc <Bk can be specified. The interval between the points ak and bk becomes narrower as the number of accumulated lines k increases. Therefore, the boundary line r = rc can be specified more accurately as the number of accumulated lines k is increased. However, if the number of lines k is increased too much, ak = bk or ak> bk, and the boundary line r = rc cannot be specified. Therefore, the number k of accumulated lines is increased in a range where ak <bk, and the radial boundary line r = rc of the inner hook region 102 is specified as rc = (ak + bk) / 2.

The creation of the cumulative histogram Hin (r, k) and the specification of the radial boundary line r = rc are performed for each of the positive and negative directions of the θ coordinate with reference to the θ coordinate θin of the inner hook 32. That is, a temporary boundary line r = rc1 = (ak + bk) / 2 is searched for the range up to k = 0 °, 1 °, 2 °,..., Θ3 (predetermined angle value), and The θ coordinate θin + θ3 is set as the boundary upper limit angle θie = θin + Δp of the inner hook region 102 (Δp = k). Further, for the range up to k = 0 °, −1 °, −2 °,..., −θ3, a temporary boundary line r = rc2 = (ak + bk) / 2 is searched, and the θ coordinate θin + k at that time is searched. Is the boundary lower limit angle θis = θin−Δm of the inner hook region 102. Then, the larger one of the two calculated temporary boundary lines r = rc1 and rc2 is selected as the true boundary line r = rc.
As described above, the boundary radius rc, the boundary upper limit angle θie, and the boundary lower limit angle θis that define the inner hook region 102 are determined for the first type spiral spring, and the inner hook region 102 is specified. With these boundary values rc, θie, and θis, an inner hook image 112 showing only the inner hook 32 as shown in FIG. 17 can be obtained from the captured image 100 of the spiral spring 30.

  Here, it is possible to determine the winding direction of the spiral spring 30 using the temporary boundary lines r = rc1 and rc2 calculated above. The winding direction of the spiral spring 30 is not specific to the spiral spring 30 but means the direction in which the spiral spring 30 is placed on the illuminator 14. The shape measuring apparatus 10 according to the present embodiment uses the two calculated temporary boundary lines r = rc1 and rc2, and determines that it is right-handed if rc1> rc2, and determines left-handed if rc1 <rc2. It is assumed that the shape measuring device 10 is placed in a right-handed direction when photographing the spiral spring 30. For this reason, when it is determined that the left-handed winding is performed at this stage, the fact is displayed on the display 20 to notify the operator. Note that the captured image 100 may be reversed left and right without notifying the operator, and the processing from step S112 may be performed again.

(2) Case of Second Type Next, processing for specifying the inner hook region 102 for the second type spiral spring 30 will be described. In the second type spiral spring 30, the inner hook 32 is located on the center of gravity G, so the inner hook region 102 does not have a fan shape as in the first type. Therefore, in the second type spiral spring 30, after obtaining the boundary radius rc as in the first type, the r coordinate Rin of the inner hook 32 and the gravity center G of the spiral spring: (cx, cy) are used. A range that satisfies the following formula is specified as the inner hook region 102.

  With the above processing, the processing from step S112 to step S124 shown in FIG. 3 is completed, and identification of the inner hook region 102 and the outer hook region 104 is completed from the captured image 100 of the spiral spring 30. That is, the specification of the hook area in step S14 shown in FIG. 2 is completed.

  Next, in step S <b> 16 of FIG. 2, preprocessing for the captured image 100 is performed prior to processing for calculating various dimensions. Specifically, binarization processing is performed on the captured image 100 to obtain a binarized image of the spiral spring 30. Also, binarization processing is performed on the inner hook image 112 (see FIG. 17) and the outer hook image 114 (see FIG. 13), and binarized inner hook image 112 and outer hook image 114 are obtained. In the following processing, the gray scale image and binarized image of the spiral spring 30, the gray scale image and binarized image of the inner hook, and the gray scale image and binarized image of the outer hook are used.

  Next, in step S18 of FIG. 2, the calculation process of the reference line x = α · y + β shown in FIGS. 18A and 18B is performed. This reference line is a straight line extending substantially along the center along the inner hook. First, as shown in FIG. 18A, a sobel filter in the x direction is applied to the grayscale image of the inner hook to detect a lateral edge. Next, two straight lines x = α1 · y + β1 and x = α2 · y + β2 extending along both sides of the inner hook 32 are detected by straight line detection by Hough transform. Then, an average straight line of these two straight lines x = α1 · y + β1, x = α2 · y + β2 is calculated as a reference line x = α · y + β. That is, α = (α1 + α2) / 2, β = (β1 + β2) / 2. After calculating the reference line x = α · y + β, as shown in FIG. 18B, the tip Ptip: (xtip, ytip) of the inner hook is obtained. A tip Ptip: (xtip, ytip) of the inner hook is a point where the y coordinate is changed downward along the reference line x = α · y + β in the binarized image of the inner hook and first becomes a black pixel.

Here, by specifying the reference line x = α · y + β, the winding direction of the spiral spring 30 can be determined by the processing described below. The winding direction of the spiral spring 30 is not specific to the spiral spring 30 but means the direction in which the spiral spring 30 is placed on the illuminator 14.
In FIG. 18 (b), the spiral spring 30 is right-handed, and the inner hook is connected to the left. In this case, when the total value of the pixel values is compared for the left and right regions with the reference line x = α · y + β as a boundary, the total value is larger in the left region. Therefore, the winding direction of the spiral spring 30 can be determined by comparing the total pixel values of the left and right regions with the reference line x = α · y + β as a boundary. In addition, when calculating the total value of the pixel values in the left and right regions, if weighting is performed to increase the pixel values of pixels that are far from the reference line x = α · y + β, Since there is a significant difference in the sum of the pixel values between them, the winding direction of the spiral spring 30 can be more correctly determined.

  Next, in step S20 of FIG. 2, a process of calculating the distance Dtip from the inner hook tip is executed. As shown in FIG. 19, the distance Dtip from the inner hook tip means the distance from the inner hook tip Ptip to the innermost strand. In this process, a binarized image of the inner hook is used, and a point that first becomes a black pixel is traced upward on the reference line x = α · y + β starting from a point one point above the tip Ptip of the inner hook. Is detected. Then, the distance between the point immediately before the detected point and the tip Ptip of the inner hook is calculated as the distance Dtip from the tip of the inner hook.

Next, in step S22 of FIG. 2, a process of calculating the inner hook length Lih is executed. In this processing, the binarized image of the inner hook, the reference line x = α · y + β, and the inner hook tip Ptip: (xtip, ytip) are used. The process of step S22 will be described below with reference to FIG.
First, a straight line y = a · x + b passing through the inner hook tip Ptip and orthogonal to the reference line x = α · y + β is obtained. Further, a straight line y = a · x + b + Na obtained by moving the straight line y = a · x + b downward (Y-axis positive direction) by Na (Na: predetermined integer) point is obtained. Next, while moving the straight line y = a · x + b + Na downward one point at a time, a straight line y = a · x + b + Na + n in which no black pixel exists on the straight line is specified. Next, the straight line y = a · x + b + Na + n−1 immediately before the straight line y = a · x + b + Na + n is set as an inner hook tangent y = as · x + bs. Next, an intersection (xcr, ycr) between the inner hook tangent y = as · x + bs and the reference line x = α · y + β is obtained. Then, the distance between the intersection (xcr, ycr) and the inner hook tip Ptip is obtained, and the distance is defined as the inner hook length Lih.

Next, in step S24 of FIG. 2, a process for calculating the center position is executed. In this processing, the calculated center position is a position indicating the center of the spiral spring, and is used as a reference in the subsequent processing. In this process, the reference line x = α · y + β, the inner hook tangent y = as · x + bs, the intersection (xcr, ycr) between the inner hook tangent and the reference line, and the distance dist from the lower end of the inner hook to the center are used. Here, the distance dist from the lower end of the inner hook to the center is a value input by the operator.
The calculation of the center position is performed according to the following procedure. First, a straight line y = as · x + bs−dist obtained by translating the inner hook tangent line y = as · x + bs upward by a distance dist is obtained. Next, an intersection point between the straight line y = as · x + bs−dist and the reference line x = α · y + β is obtained, and the intersection point is set as a center position Pc: (cx, cy).

Next, in step S26 of FIG. 2, a process for calculating the inner diameter Din is executed. In this processing, the captured image 100 of the spiral spring 30, the reference line x = α · y + β, and the center position Pc: (cx, cy) are used. The process of step S26 will be described below with reference to FIG.
First, an inner diameter straight line y = a · x + bc passing through the center position Pc: (cx, cy) and perpendicular to the reference line x = α · y + β is obtained. Next, the density of the pixels on the inner diameter straight line y = a · x + bc is confirmed while subtracting the x coordinate sequentially from the center position Pc: (cx, cy), and immediately before changing from a white pixel to a black pixel. The point p1 is detected. Similarly, the density of the pixel on the inner diameter straight line y = a · x + bc is checked while adding the x coordinate in order from the center position Pc: (cx, cy), and changes from white to black. The front point p2 is detected. Then, the detected distance between the points p1 and p2 is calculated as the inner diameter Din of the spiral spring 30.

Next, in step S28 of FIG. 2, a process of calculating the curvature radius Rin of the inner hook and the curvature radius Roh of the outer hook is executed. In this process, the binarized image of the inner hook, the binarized image of the outer hook, the coordinates of the inner hook region, and the coordinates of the outer hook region are used. The curvature radius Rin of the inner hook and the curvature radius Roh of the outer hook are calculated by the same procedure. Therefore, only the calculation procedure of the curvature radius Roh of the outer hook will be described here, and the description of the calculation procedure of the curvature radius Rin of the inner hook will be omitted. Further, there is no change in processing according to the type of the spiral spring 30.
First, using the binarized image of the outer hook and the coordinates of the outer hook region, only the outer hook region is cut out from the binarized image of the outer hook. Next, the center of gravity Gm of the outer hook is obtained from the cut image of the outer hook region. Next, contour tracking is performed on the cut image of the outer hook region, and a contour coordinate series Pi (i = 0, 1,... N−1) is acquired as shown in FIG. At this time, the noise on the contour line may be removed as necessary. Next, a distance series di between the center of gravity Gm and the contour coordinate series Pi is obtained. FIG. 23 illustrates the distance series di. Here, the start end d0 and the end dn-1 of the distance series are continuous and have a relationship of dn = d0.
After obtaining the distance series di, correlation values r (k) represented by the following formulas are obtained for k = 0, 1, 2,. The correlation value r (k) is used to specify boundary points pb and pd between the inner contour line and the outer contour line of the outer hook.

The above-described correlation value r (k) outputs 1 which is the maximum value when the distance series di is symmetric with respect to the attention point (k, dk). The points pb and pd on the contour line of the outer hook shown in FIG. 22 are points located at the boundary between the inner contour line and the outer contour line of the outer hook. The inner and outer contour lines of the outer hook have a relatively approximate shape. Therefore, the correlation value r (k) described above takes a value close to 1 at the points pb and pd located at these boundaries. In other words, the boundary position between the inner contour line and the outer contour line of the outer hook can be identified by identifying the point on the contour line where the correlation value r (k) is maximized.
Note that the correlation value r (k) shown in Equation 6 above can be replaced with another index that represents the similarity or distance (dissimilarity) between contour lines. For example, the boundary position between the inner contour line and the outer contour line may be specified using a correlation coefficient, Euclidean distance, city block distance, and the like instead of Equation 6.

FIG. 24 shows an example of the calculated correlation value r (k). As shown in FIG. 24, in the correlation value r (k), there are four points that are maximum values. These four points correspond to the four points P1, P2, P3, and P4 shown in FIG. Therefore, by calculating the correlation value r (k), four points including the boundary point between the inner contour line and the outer contour line can be specified.
Next, the four specified points are arranged in the order of contour tracking, and the distance between two points for each of an odd-ordered pair (here, point P1 and point P3) and an even-numbered pair (here, point P2 and point P4). Is calculated. Then, the pair with the larger calculated distance (here, the point P2 and the point P4) is specified as a boundary point between the inner contour line and the outer contour line.
Next, which of the first contour coordinate series P1-P3 from the boundary point P1 to the specular point P3 and the second contour coordinate series P2-P4 from the boundary point P2 to the boundary point P4, which is the inner contour line? It is determined whether it is. Therefore, for each of the first contour coordinate series P1-P3 and the second contour coordinate series P2-P4, the minimum value of the distance between the contour coordinate series and the center of gravity Gm is obtained, and the contour coordinate having the smaller minimum distance is obtained. The series is determined to be an inner contour line (P2-P4 here). As a result, as shown in FIG. 25, a contour line series having only inner contour lines can be obtained.

  Next, the maximum angle point in the inner contour line sequence is specified using the inner contour line sequence of only the inner contour line. The maximum angle point is a point at which the direction of the inner contour line changes most, and is a point indicating a bent portion of the outer hook. First, as shown in FIG. 25, both end Nb points (Nb: default integer) of the inner contour line series are deleted for the purpose of preventing erroneous detection. Next, an average vector m (k) and an average vector p (k) represented by the following formula are calculated. Correlation values r (k) are obtained for k = 0, 1, 2,.

  The average vector m (k) described above generally indicates the direction in which the contour line series from the point of interest (xtk, ytk) to Nc points before (Nc: a predetermined integer) faces. On the other hand, the average vector p (k) generally indicates the direction in which the contour line series from the point of interest (xtk, ytk) to the back of the Nc point faces. When the directions of these two average vectors m (k) and p (k) are the most different, the point of interest (xtk, ytk) can be obtained as the maximum angle point. In this embodiment, the cosine cos θk is obtained for the angle θk formed by the average vectors m (k) and p (k), and the point of interest (xtk, ytk) at which 1-cos θk is maximum is set as the maximum angle point Pmax (FIG. 26). As shown in FIG. 27, after obtaining the maximum angle point Pmax, Nd points (Nd: a predetermined integer) before and after that are cut out, and a contour coordinate series corresponding to the bent portion of the outer hook is extracted.

  Next, using the contour line sequence extracted above (see FIG. 27), a circle inscribed in the contour line sequence at the maximum angle point Pmax is calculated by Hough transform. Thereby, as shown in FIG. 28, the center Pco: (xco, yco) of the circle inscribed in the outer hook and its radius Roh, that is, the outer hook curvature radius Roh can be calculated.

Next, in step S30 in FIG. 2, a process of calculating the free angle θf is executed. In this process, the binarized image of the outer hook, the reference line x = α · y + β, the center position (coordinates) Pc: (xc, yc), and the center Pco of the outer hook curvature radius Roh are used. The process of step S30 will be described below with reference to FIG.
First, a distance Rout between the center coordinate Pc: (xc, yc) and the center Pco of the outer hook curvature radius Roh is calculated. Next, a circle having the center coordinate Pc: (xc, yc) as the center and the radius as the distance Rout is created. Next, a point closest to the center Pco of the outer hook curvature radius Roh is obtained as an inner contact Pbo of the outer hook: (xb, yb) in a coordinate group in which the created binarized image and the binarized image of the outer hook overlap. Next, a straight line y = af · x + bf passing through the center position Pc: (xc, yc) and the inner contact Pbo: (xb, yb) of the outer hook is obtained as a free angle straight line. Then, an angle formed by the free angle line y = af · x + bf and the reference line x = α · y + β is obtained as the free angle θf.

  Next, in step S32 of FIG. 2, a process of calculating the hook radius HR is executed. In this process, the center coordinates Pc: (xc, yc) and the inner contact Pbo: (xb, yb) of the outer hook are used. As shown in FIG. 30, in this process, the distance between the center coordinate Pc: (xc, yc) and the inner contact Pbo: (xb, yb) of the outer hook is calculated as the hook radius HR.

Next, in step S34 of FIG. 2, a process of calculating the outer hook length Loh is executed. In this process, the binarized image of the outer hook and the center position (coordinates) Pc: (xc, yc) are used. The process of step S34 will be described with reference to FIGS.
First, contour tracking is performed on the binarized image of the outer hook, and a contour coordinate series Pi (i = 0, 1,... N−1) as shown in FIG. 31 is acquired. At this time, the noise on the contour line may be removed as necessary. Next, an average vector angle series cos θk represented by the following equation is obtained for k = 0, 1, 2,. This average vector angle series cos θk is used to specify the corners Q1 and Q2 of the outer hook tip.

  The average vector angle series cos θk described above uses a contour coordinate series of Ne points before and after the point of interest (xk, yk) (Ne: default integer), and the point of interest (xk, yk) is the corners Q1 to Q1 of the outer hook. In the case corresponding to Q4, a value close to zero is output. Therefore, the corners Q1 to Q4 of the four outer hooks shown in FIG. 31 can be specified by obtaining the average vector angle series cos θ and obtaining four points when it takes the minimum value. Then, by selecting the two points farthest from the center position Pc among the four specified corners Q1 to Q4, the corners Q1 and Q2 at the front end of the outer hook can be specified.

  Next, a process for approximating the contour coordinate series between the corners Q1 and Q2 of the outer hook tip to a straight line is performed. For the linear approximation, for example, the least square method can be used, but the least square method is susceptible to local noise. Therefore, in this embodiment, a linear expression A · y + B · x = 1 is obtained by the following equation. The straight line A · y + B · x = 1 is referred to as the outer hook tip straight line.

Next, the outer hook tip straight line A · y + B · x = 1 is translated to a position in contact with the outer contour line of the outer hook to obtain the outer hook length Loh. Here, the direction in which the outer hook tip straight line A · y + B · x = 1 is translated is determined by the following equation. Here, (x _{(m + 1) / 2} , y _{(m + 1) / 2} ) is an intermediate point between corners Q1 and Q2 of the outer hook tip, and is an outer hook tip point.

For example, when the outer hook tip straight line A · y + B · x = 1 is moved in the −x direction by the above relational expression, for example, if it touches the outer contour line of the outer hook at the time of moving k points, The straight line of A · y + B · x = 1−B · k. The distance between the hook line end point (x _{(m + 1) / 2} , y _{(m + 1) / 2} ) and the straight line A.y + B.x = 1-B.k is calculated as the outer hook length Loh. Is done.

Next, in step S36 of FIG. 2, a process of calculating the outer hook angle θmt is executed. In this process, the binarized image of the outer hook, the free angle straight line af · x + bf, the corners Q1 and Q2 of the outer hook tip, and the outer hook curvature radius Roh are used. The process of step S36 will be described with reference to FIGS.
First, contour tracking is performed on the binarized image of the outer hook, and a contour coordinate series is acquired as in the previous step S34 (see FIG. 31). Next, as shown in FIG. 33, a corner coordinate series of Nf points (Nf: a predetermined integer) is acquired with the corners Q1 and Q2 of the outer hook tip as starting points. What starts at one corner Q1 is a contour coordinate series along the outer contour line, and what starts at the other corner Q1 is a contour coordinate series along the inner contour line. Next, as shown in FIG. 34, a shift straight line y = af · x + (yco + af · xco) obtained by translating the free angle straight line y = af · x + bf to the center Pco: (xco, yco) of the outer hook curvature radius Roh. Get. Next, as shown in FIG. 33, an intermediate coordinate series Pm located in the middle of the two sets of contour coordinate series for Nf points is obtained. Here, the calculation of the intermediate coordinate series Pm is terminated at a position where the distance from the shift straight line is less than 1. Next, the intermediate coordinate series Pm is applied to a linear expression of the least square method, and an approximate straight line y = Am · x + Bm shown in FIG. 34 is obtained. Then, the angle formed by the free angle line y = af · x + bf and the approximate line y = Am · x + Bm is calculated as the outer hook angle θmt.

  Next, in step S38 of FIG. 2, the dimensions of the respective parts calculated so far are displayed on the display 20. Display 20 includes (1) spiral spring inner diameter Din, (2) free angle θf, (3) hook radius HR, (4) outer hook length Loh, (5) inner hook length Lih, (6) outer The hook curvature radius Roh, (7) inner hook curvature radius Rih, (8) outer hook angle θmt, and (9) distance Dtip from the inner hook tip are displayed. Thus, the shape measuring process of the spiral spring 30 by the shape measuring apparatus 10 is completed.

  The shape measuring apparatus 10 of the present embodiment is not limited to the spiral spring 30 having a specific shape, and can similarly measure the shapes of the spiral springs 30 having various shapes. In particular, the shape measuring device 10 identifies the inner hook 32 and the outer hook 34 from the captured image 100 of the spiral spring 30 regardless of the shape of the spiral spring 30, and performs dimension measurement based on the inner hook 32 and the outer hook 34. Can be done accurately.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
In addition, the technical elements described in the present specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The figure which shows the structure of a shape measuring apparatus. The flowchart which shows the flow of a shape measurement by a shape measuring apparatus. The flowchart which shows the flow of the process which pinpoints a hook area | region. The figure which shows the location where a shape measuring apparatus measures a dimension. The figure which shows the picked-up image of a spiral spring (1st type). The figure which shows the picked-up image of a spiral spring (2nd type). FIG. 7A shows a polar coordinate image and FIG. 7B shows an r-direction histogram for the first type spiral spring. FIG. 8A shows a polar coordinate image and FIG. 8B shows an r-direction histogram for the second type spiral spring. The figure which expands and shows a part of FIG.8 (b). The figure which shows an outer hook area | region. The figure explaining boundary radius Rcut of an outside hook field. The figure which shows (theta) direction histogram. The figure which shows an outer hook image. The figure which shows an inner hook area | region. The figure which shows an inner hook area | region in a polar coordinate image. The figure explaining a cumulative histogram. The figure which shows an inner hook image. The figure explaining the calculation process of a reference line. The figure explaining the calculation process of distance Dtip from an inner hook front-end | tip. The figure explaining calculation processing of inner hook length Lih. The figure explaining the calculation process of the internal diameter Din. The figure explaining the outline coordinate series and distance series of an outer hook image. The graph which shows an example of distance series di. The graph which shows an example of correlation value r (k). The figure which shows the coordinate series of the inner side outline of an outer hook. The figure which shows the angle | corner which the average vector used for calculation of a maximum angle point forms. The figure which shows the outline coordinate series of the bending part of an outer hook. The figure which shows the circle | round | yen inscribed to an outer hook, and its radius (outer hook curvature radius) Roh. The figure explaining calculation processing of free angle thetaf. The figure explaining the calculation process of hook radius HR. The figure explaining the process which pinpoints corner | angular part Q1, Q2 of an outer hook front-end | tip. The figure explaining calculation processing of outer hook length Loh. The figure which shows the origin outline coordinate series which makes corner | angular part Q1, Q2 of an outer hook front-end | tip start. The figure explaining calculation processing of outside hook angle thetamt.

Explanation of symbols

10: shape measuring device 12: stage 14: illuminator 16: CCD camera 18: communication line 20: display 22: computer 30: spiral spring 32: spiral hook inner hook 34: spiral spring outer hook

Claims (10)

It is a shape measuring device that measures the shape of a spiral spring that extends spirally from the inner hook to the outer hook,
An image input means for inputting a photographed image of the spiral spring;
Image conversion means for creating a polar coordinate image obtained by converting the captured image into polar coordinates;
Hook position specifying means for specifying an inner hook position where the inner hook in the photographed image is photographed and / or an outer hook position where the outer hook is photographed using the polar coordinate image;
Equipped with a,
The hook position specifying means creates an r-direction histogram in which each pixel value of the polar coordinate image is added for each position in the radial axis direction, and specifies the inner hook position and / or the outer hook position using the r-direction histogram. shape measuring device you wherein a. Using the inner hook position and / or the outer hook position, the hook area specification for specifying the inner hook area in which the inner hook is photographed in the photographed image and / or the outer hook area in which the outer hook is photographed. The shape measuring apparatus according to claim 1, further comprising means. The hook area specifying means includes an r-direction histogram obtained by adding each pixel value of the polar coordinate image for each position in the radial axis direction, and a θ-direction histogram obtained by adding each pixel value of the polar coordinate image for each position in the angle axis direction. The shape measuring apparatus according to claim 2 , wherein the shape measuring device is created and the inner hook region and / or the outer hook region is specified using the r-direction histogram and the θ-direction histogram. The hook area specifying means specifies a radial boundary position of the outer hook area using the r-direction histogram, and specifies a boundary position of the outer hook area in the angle axis direction using the θ-direction histogram. The shape measuring apparatus according to claim 3 . The hook region specifying means sequentially extracts lines parallel to the radial axis of the polar coordinate image, creates a cumulative histogram in which each pixel value on the extracted line is added for each position in the radial axis direction, and the cumulative histogram shape measuring apparatus according to claim 3 or 4, wherein the identifying the said hook region using a histogram. The image converting means, said calculating the centroid of the image of the spiral spring taken in the captured image, according to any one of claims 1 to 5, characterized in that the polar coordinate conversion around its center of gravity Shape measuring device. A line that is parallel to the radial axis of the polar coordinate image is sequentially extracted, and a cumulative histogram is created in which each pixel value on the extracted line is added for each position in the radial axis direction. The shape measuring device according to any one of claims 1 to 6 , further comprising first winding direction discriminating means for discriminating a winding direction of the first winding direction. 2. The apparatus according to claim 1, further comprising second winding direction determining means for determining the winding direction of the spiral spring by dividing the photographed image by a straight line along the inner hook and comparing the two divided areas. The shape measuring apparatus according to any one of 1 to 7 . It is a shape measuring method for measuring the shape of a spiral spring that extends in a spiral shape from an inner hook to an outer hook.
Image input processing for inputting a captured image of the spiral spring;
Image conversion processing for creating a polar coordinate image obtained by polar conversion of the captured image;
Using the polar coordinate image, the hook position specifying process for specifying the inner hook position where the inner hook is photographed and / or the outer hook position where the outer hook in the photographed image is photographed in the photographed image. When,
Was executed,
In the hook position specifying process, an r-direction histogram is created by adding each pixel value of the polar coordinate image for each position in the radial axis direction, and the inner hook position and / or the outer hook position is specified using the r-direction histogram. shape measuring how to characterized in that. It is a program for measuring the shape of a spiral spring that spirally extends from an inner hook to an outer hook.
Image input processing for inputting a captured image of the spiral spring;
Image conversion processing for creating a polar coordinate image obtained by polar conversion of the captured image;
Using the polar coordinate image, the hook position specifying process for specifying the inner hook position where the inner hook is photographed and / or the outer hook position where the outer hook in the photographed image is photographed in the photographed image. When,
Was executed,
In the hook position specifying process, an r-direction histogram is created by adding each pixel value of the polar coordinate image for each position in the radial axis direction, and the inner hook position and / or the outer hook position is specified using the r-direction histogram. program that is characterized in that.