JP2014030496A - Method for detecting button direction, device for detecting button direction, and device for feeding button - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a button direction (an angle around an axis perpendicular to a front and back surface) from a front surface image of the button with high accuracy and with high efficiency.SOLUTION: Upon the calculation of a relative angle of a detection-objective button to a normal button direction by an image-processing device, if detecting a normal button direction on the basis of a front surface image of a sample button which indicates the normal button direction, specifying the arrangement of a button hole and the rotation symmetry of a logo and obtaining logo characteristics, specifying a position of the button hole from the front surface image of the detection-objective button, calculating a button hole deviation angle to a normal button direction, and specifying which is the highest in degree of correlation when comparing with logo characteristics respectively as for an image in which a position of the button hole of the detection-objective button is made to agree with the normal button direction by rotating by an amount of button hole deviation angle and an image further rotated from there by an amount of relative angle of a rotationally asymmetrical mutual direction, an angle θb which is obtained by adding a rotational angle θm to a button hole deviation angle concerning that is output as a button direction of the detection-objective button.

Description

  The present invention relates to a button direction detection method and a button direction detection device for detecting a button direction defined by an angle about an axis perpendicular to the front and back surfaces of a button sewn on a sewing product.

In the sewing field, as described in Patent Document 1, for example, a button supply device including a transport mechanism that supplies a button to a button sewing machine that sews a button to a sewing product is known.
Furthermore, Patent Documents 2, 3, and 4 describe a technique in which a button, a camera, illumination, an image processing device, and the like are attached to a button supply device, and button front / back discrimination and hole position detection are performed by image processing.
Further, in fields other than sewing, a technique for detecting characters and labels arranged in a ring shape on a circular object and detecting the direction of the circular object from its arrangement by image recognition has been proposed in many fields.
For example, in the “dot recognition character recognition method for optical discs” in Patent Document 5 and the “identification symbol recognition method for optical discs” in Patent Literature 6, characters placed on the optical disk are detected, The “can lid manufacturing apparatus” in Document 7 detects the direction of the can from the position of the symbol printed on the can lid.

Japanese Patent No. 2659439 JP 2010-78562 A JP 2010-104569 A JP 2010-131178 A Japanese Patent No. 3249314 Japanese Patent No. 3258828 Japanese Patent No. 3844228

However, the conventional button supply device has a function to distinguish the front and back of the button and a function to supply so that the needle entry position at the time of sewing matches the button hole position. There was no function to supply according to the sewing direction. Therefore, when it is desired to align the sewing direction of the button with the logo, the sewing machine operator directly determines the button direction visually and sets it at the sewing position without using the button supply device.
For this reason, there is a need for a button supply device equipped with a camera and an image processing device to detect the button direction simultaneously with front / back discrimination and hole position detection.
Button logos can be arranged in various forms. Some logos exist on a part of the circumference (FIGS. 22 (a) (b) (c)), while others exist on the whole circumference (FIG. 22). (d) (e) (f)). Also, the same logo is in a rotationally symmetric arrangement (Fig. 22 (c) (d)), there is no symmetry (Fig. 22 (a) (b) (e)), Some of them have asymmetrical arrangements (FIG. 22 (f)). The symmetry and direction of the buttons are determined not only by the logo layout but also by the combination with the hole layout.
That is, in button sewing, a plurality of button holes through which the sewing needle moves up and down is lowered with respect to the sewing product at a predetermined angle, and the direction of the logo or pattern on the button is set to a predetermined angle. , Etc. are required, but the recognition technology for the letters and labels arranged in a ring shape in a circular shape other than the sewing mentioned above considers the positional relationship between the button hole and the logo or the symmetry of the logo. Direction detection processing cannot be performed.

  Accordingly, the present invention relates to a button direction detection method and a button direction detection device for detecting a button direction defined by an angle about an axis perpendicular to the front and back surfaces of a button sewn on a sewing product, and a positional relationship between a button hole and a logo. Alternatively, in consideration of the symmetry of the logo, the object is to detect the button direction from the surface image of the button with high accuracy and high efficiency.

The invention according to claim 1 is a button direction detection method for detecting a button direction defined by an angle about an axis perpendicular to the front and back surfaces of a button sewn on a sewing product.
When the image processing apparatus calculates the relative angle of the detection target button as the target of the button direction detection with respect to the normal button direction as the button direction of the detection target button,
(1) Obtain a surface image of a sample button that has a button hole and a logo and is provided to teach the normal button direction;
(2) Based on the surface image of the sample button, the normal button direction is detected, the button hole arrangement in the normal button direction, and the rotational symmetry of the logo when rotated around the axis while maintaining the button hole arrangement In addition to specifying the gender, get the logo features in the normal button direction,
(3) Obtain a surface image of the detection target button,
(4) Identify the position of the button hole of the detection target button from the surface image of the detection target button,
(5) Calculate the button hole deviation angle with respect to the button hole in the normal button direction of the button hole of the detection target button,
(6) When the rotational symmetry is omnidirectional mutual rotational symmetry (for example, FIG. 22 (d)), the surface image of the detection target button is rotated by the button hole shift angle to determine the position of the button hole of the detection target button. For the image in which the position of the button hole in the normal button direction is matched, the degree of correlation when calculating the degree of correlation when compared with the logo feature and exceeding a predetermined threshold value, the button hole deviation angle is determined. Output as direction,
(7) When the rotational symmetry has a non-rotational symmetry mutual orientation, the surface image of the detection target button is rotated by the button hole misalignment angle, and the position of the button hole of the detection target button is determined as a regular button. Image aligned with the position of the buttonhole in the direction, and relative rotationally symmetric relative angles (for example, 90 °, 180 °, 270 ° in FIG. 22A, 90 ° in FIG. 22C) ) For each of the images rotated by an amount corresponding to the logo feature, the degree of correlation when compared with the logo feature is calculated. An angle obtained by adding a rotation angle from a state of being rotated by a minute amount to the button hole deviation angle is output as a button direction of the detection target button.

The invention according to claim 2 is the button direction detection method according to claim 1,
The surface image of the sample button is divided into divided areas divided into the same number of angle ranges as the number of button holes around the button center, and based on the degree of correlation when different divided areas are compared with each other, the button center is set as the center of rotation. The rotational symmetry of the logo of (2) is specified by discriminating the rotational symmetry.

The invention according to claim 3 is the button direction detection method according to claim 2,
The edge image is extracted by differentiating the surface image of the sample button along the circumferential direction around the center of the button, the diameter section where the edge amount is maximum is specified, and the divided area is limited to the diameter section. And calculating the degree of correlation.

The invention according to claim 4 is the button direction detection method according to claim 2 or claim 3, wherein
The degree of correlation is calculated by performing a polar coordinate conversion on the divided areas and comparing the divided areas.

The invention according to claim 5 is the button direction detection method according to claim 1,
The edge image is extracted by differentiating the surface image of the sample button along the circumferential direction around the center of the button, the diameter section in which the edge amount is maximum is specified, and the above (2) It is characterized by acquiring the logo feature of.

A sixth aspect of the present invention provides the button direction detecting method according to the fifth aspect,
The logo feature is memorized by converting polar coordinates around the center of the button,
In (6) and (7), the degree of correlation is calculated after performing polar coordinate conversion on an image region to be compared with the logo feature of the surface image of the detection target button.

The invention according to claim 7 is the button direction detection method according to claim 1,
The acquisition of the surface image of the sample button of (1) is performed by illuminating the surface of the sample button with a predetermined illumination and capturing it with a camera,
The surface image of the detection target button in (3) is acquired by illuminating the surface of the detection target button with the predetermined illumination and capturing the image with the camera.

The invention according to claim 8 is the button direction detection method according to claim 1,
Based on the surface image of the sample button, the button hole of the sample button and the button outer diameter are detected. Based on the surface image of the detection target button, the button hole of the detection target button and the button outer diameter are detected. When the button outer diameter is different from the button hole of the detection target button and the button outer diameter, information indicating an abnormality is output and button direction detection is interrupted.

The invention according to claim 9 is the button direction detection method according to claim 1,
When the predetermined threshold value is not exceeded in (6) and when no one exceeding the predetermined threshold value is specified in (7), information indicating an abnormality is output and the button direction is output. The detection is interrupted.

The invention according to claim 10 is a button direction detection device for executing the button direction detection method according to claim 1,
An illumination device, a camera, and an image processing device;
The image processing apparatus includes:
The surface image of the sample button illuminated by the illumination device and imaged by the camera is input, and the above (2) is executed.
(4) to (7) are executed by inputting a surface image of a detection target button illuminated by the illumination device and imaged by the camera.

Invention of Claim 11 is a button supply apparatus provided with the button direction detection apparatus of Claim 10, and the conveyance mechanism which conveys a button to a predetermined supply position,
The button direction detection device may be configured to detect a button direction of a button conveyed by the conveyance mechanism.

The invention according to claim 12 is the button supply device according to claim 11,
The image processing device detects the button hole and button outer diameter of the sample button based on the surface image of the sample button, detects the button hole and button outer diameter of the detection target button based on the surface image of the detection target button, When the button hole and button outer diameter of the sample button are different from the button hole and button outer diameter of the detection target button, the detection target button is excluded from the transport path to the predetermined supply position of the transport mechanism. It has a mechanism.

The invention according to claim 13 is the button supply device according to claim 11,
When the predetermined threshold value is not exceeded in (6), and when one that exceeds the predetermined threshold value is not specified in (7), the button to be detected is moved to the transport mechanism. It has a mechanism for excluding from the transport path to a predetermined supply position.

  According to the first aspect of the present invention, when calculating the relative angle of the detection target button as the button direction detection target with respect to the normal button direction as the button direction of the detection target button, the surface of the imaged sample button Based on the image, the normal button direction is detected, the button hole arrangement in the normal button direction and the rotational symmetry of the logo when rotated around the axis while maintaining the button hole arrangement are specified, and After acquiring the logo characteristics in the button direction, based on the surface image of the button to be detected that was captured later, first calculate the button hole misalignment angle by the relativity of the button holes, and rotate as necessary according to the contents of the rotational symmetry By comparing with the logo feature while rotating only the corner, the button direction of the detection target button can be detected with high accuracy and high efficiency. Therefore, it is possible to sew the buttonhole and the logo or pattern on the button at a predetermined angle with respect to the sewing product.

  According to the second aspect of the present invention, the image is divided into divided regions divided into the same number of angle ranges as the number of button holes with the button center as the center, and different divided regions are compared with each other. Thus, rotational symmetry can be reliably determined.

  According to the invention described in claim 3, since the diameter section where the edge amount is maximum due to the presence of the logo is specified and the divided area for determining the rotational symmetry is limited to the diameter section, the logo is occupied. The degree of rotation becomes high, and rotational symmetry can be determined efficiently and accurately in image processing.

  According to the fourth aspect of the present invention, since the divided area for determining the rotational symmetry is subjected to polar coordinate conversion, the calculation becomes easy.

  According to the invention described in claim 5, since the diameter section where the edge amount is maximum due to the presence of the logo is specified and the logo feature is acquired from the image of the diameter section, the degree of logo occupancy is increased and the efficiency is improved. The button direction can be detected with high accuracy.

  According to the sixth aspect of the present invention, since the logo feature and the image to be compared with this are subjected to polar coordinate conversion, the calculation becomes easy.

  According to the invention described in claim 7 or 10, the imaging conditions of the surface image of the sample button and the surface image of the detection target button can be made constant, and the detection error due to the difference in imaging conditions can be reduced.

  According to the invention described in claim 8, the button direction detection is interrupted by detecting the abnormality due to the difference in the button outer shape represented by the button hole and the outer diameter, and the logo of the detection target button is compared. The useless processing can be avoided, the abnormality can be notified if necessary, and the button can be excluded so that the button is not supplied to the predetermined supply position as in the invention described in claim 12.

  According to the ninth aspect of the present invention, when a certain degree of identity reliability cannot be obtained by comparing logos, the button direction detection is interrupted and detected as an abnormality, and the button direction of the detection target button is calculated. And wasteful processing such as output can be avoided, an abnormality is notified if necessary, or the button is excluded so that the button is not supplied to a predetermined supply position as in the invention of claim 13. Can do.

  According to the eleventh aspect of the present invention, it is possible to detect the button direction of the button conveyed by the conveyance mechanism of the button supply device, and to configure the control means such as correcting the button direction based on the detected button direction. can do.

1 is a configuration block diagram of a button direction detection device according to an embodiment of the present invention. It is a top view of the button supply apparatus concerning one embodiment of the present invention. It is the front view (a) and partial front view (b) of the button supply apparatus which concern on one Embodiment of this invention. It is a flowchart which shows the procedure of the teaching process in one Embodiment of this invention. It is a button image schematic diagram showing an example in which a button and a background have high contrast. It is a button image schematic diagram for demonstrating the external shape detection of the button in one Embodiment of this invention. It is a buttonhole part image schematic diagram for demonstrating the detection of the buttonhole in one Embodiment of this invention. It is a figure which shows the direction of the scanning line changed for buttonhole search in one Embodiment of this invention. FIG. 5 is a schematic diagram of a button hole image for explaining detection of a button hole in an embodiment of the present invention, where (a) shows a two-hole button, (b) shows a three-hole button, (c ) Indicates a four-hole button. (a) is a hole arrangement | positioning figure which shows the hole arrangement | positioning pattern which the sewing machine with a button in one Embodiment of this invention can sew, (b) is a hole arrangement | positioning figure of the sample button imaged by teaching process. In one Embodiment of this invention, it is the schematic diagram (a) of the surface image of the imaged button, and the schematic diagram (b) of the image which carried out the polar coordinate conversion of this. In one embodiment of the present invention, an example of an image obtained by polar-coordinate conversion of a surface image of a captured button (a), an image (b) obtained by extracting edge components in the horizontal direction (circumferential direction before polar coordinate conversion), and radial direction It is an edge amount distribution diagram (c) with respect to the position. In one Embodiment of this invention, it is a schematic diagram which shows that a polar coordinate conversion image is limited to a logo presence diameter area, and is divided | segmented into the number of button holes, (a) is a thing of a two-hole button, (b) Shows a three-hole button and (c) shows a four-hole button. FIG. 14 is a schematic diagram showing that a logo feature extraction target area is specified for the example of FIG. It is a flowchart which shows the procedure of the button direction detection process in one Embodiment of this invention. In one embodiment of the present invention, (a) is a schematic diagram of a button hole showing an example of a hole arrangement pattern registered based on the teaching of a sample button, and (b) is a provisional coordinate axis that matches the button surface to be detected and the button hole. (C) is a schematic diagram obtained by polar-coordinate conversion of the logo existing diameter section of (b). FIG. 5 is schematic button surface diagrams (a), (b), (c), and (d) showing candidates for temporary coordinate axes in an embodiment of the present invention. In one embodiment of the present invention, (a) is a schematic diagram of an example of a button surface arranged in a normal button direction, (b) is a schematic diagram depicting a detection target button surface and a provisional coordinate axis aligned with the button hole. Fig. (C1) is a diagram in which (a) is rotated according to the coordinates of (b), and (c1) is a diagram in which (c1) is rotated 90 degrees clockwise (c2), (c3), (c4) . It is a polar coordinate conversion image schematic diagram for explaining the logo angle search in one embodiment of the present invention, (a) is based on the detection target button, (b) ~ (e) of the comparison verification based on the sample button This is a template for shifting by 90 degrees in order from (b). In the polar coordinate conversion image schematic diagram for explaining the logo angle search in one embodiment of the present invention, the logo is a 180-degree rotationally symmetric four-hole button, (a) is based on the detection target button , (B) and (c) are templates for comparison and collation based on the sample buttons, and (c) which is shifted by 90 degrees from (b). In one embodiment of the present invention, (a) is a schematic diagram of an example of a button surface arranged in a normal button direction, and (b) illustrates an angle θb indicating the button direction of the detection target button with respect to the normal button direction. It is a schematic diagram. It is the surface schematic diagram of the four-hole button by which the logo was formed in the outer peripheral surface part of a button hole.

An embodiment of the present invention will be described below with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention.
In this embodiment, a button supply device equipped with a transport mechanism for transporting a button to a button sewing machine is equipped with a button direction detection device.

(Outline of the button direction detection device)
FIG. 1 shows the configuration of the button direction detection device of the present embodiment. In FIG. 1, 1 is a camera, 2 is an illumination device, 3 is an image processing device, and the image processing device 3 includes a CPU 3-1, a memory 3-2, a communication port 3-3, and the like.
A command can be transmitted to and received from a control unit (not shown) of the button supply device via the communication port 3-3, and the button direction detection device instructs the front / back discrimination request from the control unit of the button supply device via the communication port 3-3. Or the button direction detection device returns the button direction detection result to the control unit of the button supply device via the communication port 3-3.
The camera 1 and the illumination device 2 are connected to the image processing device 3, and the CPU 3-1 determines an instruction received from the button supply device, issues an imaging instruction to the camera 1, and controls the lighting time of the illumination device 2. An image captured by the camera 1 is stored in the memory 3-2.
In addition, the CPU 3-1 executes a process described later based on the captured image.

(Outline of the button supply device)
2 and 3 show a button supply device in which the camera 1 and the illumination device 2 of the button direction detection device are installed. The mechanism described below is only an example. 2 and 3, reference numeral 13 denotes a cylindrical button supply unit. The button B accommodated in the bottom surface 13 a is lifted along a spiral passage 13 b formed on the inner wall surface by a predetermined slight vibration, and a carry-out port is provided. It can discharge sequentially from 13c. The button supply unit 13 has a button front / back discrimination function.
When the operation type bar 101 is installed at the carry-out port 13c, and it is determined that the passing button is on the back side, the control unit of the button supply device closes the carry-out port 13c with the bar 101 and presses the button. Drop on the bottom surface 13a.
On the other hand, if the determination result is that the upper surface is the front, the control unit of the button supply device arranges the bar 101 so as to guide to the carry-out port 13c, and discharges the button from the carry-out port 13c.

The button discharged from the carry-out port 13 c is received by the button holding portion 14 a of the button rotation conveyance mechanism 14, moved by the button rotation conveyance mechanism 14, and received by the button holding portion 21 a of the next button rotation conveyance mechanism 21. The button rotation conveyance mechanism 21 is disposed on the top of the locking pin 28 a at the tip of the swivel arm 28. A camera 1 and a lighting device 2 are installed above the camera 1 and the lighting device 2.
When a button is supplied to the upper portion of the locking pin 28a, the control unit of the button supply device makes an image pickup request to the image processing device 3. The image processing device 3 issues an imaging request to the camera 1, lights up the illumination device 2 in accordance with the imaging timing, captures a button image, detects an angle with respect to the normal button direction from this image, and sends it to the control unit of the button supply device. Send the result. The control unit of the button supply device rotates the locking pin 28a to the button hole position by the motor 61 below the locking pin 28a and inserts it into the button hole. Then, the button is held in the normal button direction while holding the button. Rotate the button so that it is positioned. The button is transferred to the button holding mechanism 12b by the turning arm 28 and is set at a sewing position (not shown).

(Details of button direction detection)
Next, the details of the processing of the button direction detection method and the button direction detection device using an image will be described.
The button direction is detected by the teaching processing in which the image processing device 3 learns the normal button direction and the like so that the buttons are aligned in the normal button direction in the process of being transported to the button sewing machine by the transport mechanism of the button supply device. This is performed by executing button direction detection processing for detecting the button direction of the button. The button imaged in the teaching process is a sample button selected from a specific button having a buttonhole and a logo, and the imaging surface is the surface of the sample button. By completing the teaching process, the button direction of a specific button can be detected.

(Teaching process)
First, the teaching process will be described. A flowchart of the teaching process is shown in FIG.
In step S401, the CPU 3-1 of the image forming apparatus 3 causes the camera 1 to capture an image of the surface of the sample button while illuminating the surface of the sample button on the illumination device 2. The button direction of the sample button at this time is set to be supplied to the sewing button at the normal button direction at the time of sewing. For example, in the case of the button supply device of FIG. 3, the state where the button is set in the button holding mechanism 12b in the normal button direction at the time of sewing is held by the turning arm 28 with the locking pin 28a and rotated to the lower part of the camera 1 as it is. Thus, the button direction of the sample button at the imaging position of the camera 1 becomes a normal button direction in order to realize a correct button direction at the time of sewing. However, since there is an arrangement error, it is corrected by image processing as will be described later.
In imaging, in order to increase the contrast between the button and the background as shown in FIG. 5, for example, in the button supply device of FIG. It is preferable to switch the color to black or white depending on the color.

Next, in step S402, the CPU 3-1 calculates the button outer diameter size L.
The separation density of the background and the button is obtained by a known threshold value acquisition means such as a discriminant analysis method. If the background density is lower than the separation density as shown in FIG. If the background density is higher than the separation density as shown in (b), a density lower than the separation density is scanned from the upper, lower, left, and right image ends.
As shown in FIG. 6, the upper end Y0, the lower end Y1, the left end X0, and the right end X1 of the button are searched, and the average of the upper and lower end distance YL and the left and right end distance XL is set as the button outer diameter size L.

  Next, in step S403, the CPU 3-1 calculates the temporary center position of the button. The CPU 3-1 uses the midpoint position (cx, cy) of each of the left and right ends and the upper and lower ends of the button calculated in step S 402 as the temporary center of the button.

Next, in step S404, the CPU 3-1 detects the number of button holes and the arrangement pattern. First, the CPU 3-1 searches for a background (button hole) on a scanning line at an arbitrary radial position outward from the button center (cx, cy).
When the button hole is found, as shown in FIG. 7, the edge positions Ep0 and Ep1 with the button hole are detected on the scanning line Ln0, and another scan that passes through the midpoint Mp and is orthogonal to the preceding scanning line Ln0. Search on the line Ln1 to detect the edge positions Ep2 and Ep3 of the button holes. The button center position Hc and hole diameter Hs are calculated using the detected four edge points Ep0, Ep1, Ep2, and Ep3.
If no hole is found by scanning from the center, +90 degrees, -90 degrees, +45 degrees, -45 degrees, +22.5 degrees, -22.5 degrees with respect to the first scanning line Ln0 as shown in FIG. , +67.5 degrees, -67.5 degrees and sequentially change the scanning direction.
If the first buttonhole (first buttonhole) is detected, the second buttonhole search uses the scan line as the line connecting the center of the first buttonhole and the center of the button (cx, cy), and the center of the button Search from (cx, cy) to the opposite side of the first buttonhole.
If not found, a search is made in a direction having a relative angle of ± 120 degrees with respect to the center direction of the first button hole from the button center (cx, cy), and the second and third button holes are searched. As a result, when the second and third button holes can be detected, it is determined that the button has three holes as shown in FIG. 9A, and all the button holes have been detected.
If the second button hole can be detected diagonally to the first button hole, the third and fourth buttons are searched at the ± 90 degree position of the first button hole. If the third and fourth button holes can be detected, it is determined that the button has four holes as shown in FIG. 9B, and if the third and fourth button holes cannot be detected, two buttons as shown in FIG. 9C. It is determined that the button is a hole button, and all the button holes have been detected.

Next, in step S405, the CPU 3-1 calculates the button center and the inclination angle α for correcting the normal button direction. The button center is the average value of the button hole position coordinates detected in step S404 in the plane coordinates having (cx, cy) as the origin.
The image processing apparatus 3 stores in advance hole arrangement patterns that can be sewn by the button sewing machine as shown in FIG. 10 (a), and the number and positions of these hole arrangement patterns and the button holes detected in step S404. Collation is performed to identify the hole arrangement pattern having the same number of button holes and the closest arrangement angle, and the inclination angle α of the hole arrangement detected in step S404 with respect to the identified hole arrangement pattern (see, for example, FIG. 10B). calculate.
When a sample button is set in the button clamping mechanism 12b, an arrangement error may occur. When the button direction of the sample button including the arrangement error is treated as a normal button direction as it is, it is supplied by the button supply device. When the button direction of the button is detected and rotated so as to be arranged in the normal button direction, the same arrangement as the sample button is reproduced and the same arrangement error occurs. By calculating the tilt angle α and performing pre-cancellation based on the tilt angle α, the button direction can be detected and corrected with high accuracy.

Next, in step S406, the CPU 3-1 converts the surface image of the sample button into polar coordinates. As shown in FIG. 11A, the range from the button center to the button radius (L / 2) is converted over 360 degrees. The base point of the angle is a position advanced by the inclination angle α obtained in step S405. Thereby, the pre-cancellation based on the inclination angle α described above is completed. The obtained polar coordinate conversion image is shown in FIG.
In the polar coordinate conversion image, the horizontal axis is the distance from the center, and the vertical axis is the angle. However, from the following processing efficiency, the horizontal axis is the angle (θ) and the vertical axis is the center as shown in FIG. Distance (R) from
The conversion from the original image of the XY coordinate system as shown in FIG. 11A to the polar image (θR coordinate system image) as shown in FIG. The conversion to the original image of the system can be performed by Equation 2.

  Next, in step S407, the CPU 3-1 identifies a diameter section where the logo exists. As shown in FIG. 12 (a), button edge irregularities and marble patterns may appear. Therefore, differentiation is performed in the range of 0 ≦ R ≦ L / 2 along the horizontal direction of the polar coordinate conversion image (that is, the circumferential direction on the original image) so that the logo position can be easily detected accurately, as shown in FIG. As shown, only the edge component in the horizontal direction is extracted. Next, as shown in FIG. 12 (c), the sum of the R values of the edge components is obtained. In the section where the logo is present, the edge amount is increased as compared with the section where the logo is not present. Therefore, the diameter section where the sum of the edges is maximum (indicated by r in FIG. 12C) can be specified as the diameter section where the logo is present. .

Next, in step S408, the CPU 3-1 determines the rotational symmetry of the logo. First, it is limited to the logo existing diameter section on the polar coordinate conversion image, and is divided into divided areas divided into the same number of angle ranges as the number of button holes around the button center.
If it is a two-hole button, it is divided into divided areas A1 and A2 divided into two every 180 degrees as shown in FIG. 13A, and if it is a three-hole button, it is 120 as shown in FIG. 13B. If the button is divided into three divided areas A3, A4, and A5 divided every three degrees, and a four-hole button is used, the divided areas A6, A7, A8, and A9 divided into four divided every 90 degrees as shown in FIG. Divide.
Based on the degree of correlation when different divided areas are compared with each other, the rotational symmetry about the button center is determined. Whether the correlation level is high or low is determined using a correlation determination threshold value stored in the image processing apparatus 3. For example, in the case of two holes, if the correlation between the two divided areas A1 and A2 is high, the logo can be rotated 180 degrees and the direction can be determined by only the button hole. If the correlation between the two divided areas A1 and A2 is low, It turns out that it is an asymmetric button whose direction cannot be determined only by the button hole position.
Similarly, the three-hole button also has a high correlation between the two divided regions selected from the three divided regions A3, A4, and A5 (all three combinations of A3-A4, A3-A5, and A4-A5). If it is a correlation, it becomes a 120-degree rotational symmetry in which the direction can be determined only by a button hole, and if the correlation is low, it becomes an asymmetric button.
In the case of a four-hole button, if the correlation between the two divided areas selected from the four divided areas A6, A7, A8, and A9 is all combinations (six combinations), it is 90 degree rotationally symmetric and only the buttonhole position If only the correlation between the two divided areas A6 and A8 and the correlation between the divided areas A7 and A9 are high, the direction cannot be detected by the buttonhole alone. If the control is half, and the correlation is other than this, it can be seen that the logo is asymmetric.
Here, the correlation calculation method uses normalized correlation calculation between image data, edge component extraction, and edge feature correlation calculation. The correlation determination threshold value is an empirical value obtained in past experiments and verifications of the same process using the correlation calculation method.
As described above, it is possible to specify the rotational symmetry of the logo when rotated around the axis while maintaining the arrangement of the button holes.

Next, in step S409, the CPU 3-1 extracts a logo feature. The logo feature extraction target area may be the divided area itself in step S408, but if the logo is local, it is efficient to extract only a part in accordance with that. For example, it is good also as one area | region straddling the some division area of step S408 like area | region M0, M1 shown in FIG.
The logo feature is extracted from the set logo feature extraction target region, which differs depending on the correlation calculation method in step S408 or step S1408 (described later). For example, in the case of normalized correlation calculation between image data, the image data in the target area becomes the logo feature data, and if the edge feature of the logo is extracted and correlated with the edge feature, it exists in the target region The edge position and edge information (gradient vector strength, direction, etc.) to be used as the logo feature data.

  Next, in step S410, the CPU 3-1 registers button data. The button data to be registered include the button outer diameter detected in step S402, the number of button holes detected in step S404, the button hole arrangement pattern searched in step S405, the button hole diameter detected in step S404, and step S404. From the hole position calculated in step S407, the logo existing diameter detected in step S407 (MR in FIG. 14) and the logo diameter range (MRw in FIG. 14), and the rotational symmetry of the logo specified in step S408 (asymmetric, 180 degrees). Point symmetry, 120 degree point symmetry, 90 degree point symmetry), number of logo features extracted in step S409, angle of logo feature extraction area (M0θ, M1θ in FIG. 14) and angle range (M0θw, M1θw in FIG. 14) The logo feature data obtained from each extraction area. These data are stored in the memory 3-2 of the image processing apparatus 3, and the teaching process is terminated.

(Button direction detection process)
Next, the button direction detection process will be described. A flowchart of the button direction detection process is shown in FIG.
Steps S1401 to S1404 of the button direction detection process are the same as steps S401 to S404 of the teaching process.
In step S1401, as described above, the image processing device 3 controls the camera 1 and the illumination device 2 in response to an imaging request from the control unit of the button supply device when the button is supplied to the upper portion of the locking pin 28a. Button image. Thereby, CPU3-1 acquires the surface image of a detection target button.

Next, in step S1405, the CPU 3-1 performs a defect inspection of the outer diameter size of the detection target button and the button hole arrangement.
If the detected outer diameter size, number of button holes, button hole diameter size, and button hole interval are different from those of the sample button registered in step S410, information indicating abnormality is sent to the control unit of the button supply device. Output (S1411) and interrupt the button direction detection process.
Here, it is assumed that the inspection threshold value of each dimension and position is registered in advance and stored in the image processing apparatus 3 from the viewpoint of physical restrictions of the button supply device and the sewing machine and the finished quality of the sewing product.

Next, in step S1406, the CPU 3-1 sets the temporary coordinates of the button hole.
The CPU 3-1 calculates the button hole center from the detected button hole position average, and sets a coordinate axis so that the button hole coordinates at the time of sewing (for example, FIG. 16A) are the same as the button hole coordinates ( (B)). As shown in FIGS. 17 (a), (b), (c), and (d), there are a plurality of candidates for the orientation of the coordinate axes. However, since this process is established regardless of which is selected, the rotation angle from the button hole arrangement pattern is here. Is selected (FIG. 17 (a), FIG. 16 (b)). This rotation angle is the button hole deviation angle θx. The button hole deviation angle θx is a button hole deviation angle with respect to a button hole (indicated by the button hole arrangement pattern) in the normal button direction of the button hole of the detection target button. The CPU 3-1 calculates the button hole deviation angle θx and stores it in the memory 3-2.

Next, in step S1407, the CPU 3-1 extracts a logo existing diameter section of the captured image and performs polar coordinate conversion (FIG. 16 (c)). The identification of the logo existing diameter section and the polar coordinate conversion are performed in the same manner as the teaching process.
Next, in step S1408, the CPU 3-1 performs a logo angle search.
Since the positional relationship between the button hole and the logo is known by the teaching process (for example, FIG. 18 (a)), the candidate position of the logo can be specified from the position of the button hole (FIG. 18 (b)) (FIG. 18 (c1) ˜ (c4)). FIG. 18B shows the surface of the detection target button and the temporary coordinate axis. 18 (b) and FIG. 18 (c1) to (c4), the correct answer is shown in FIG. 18 (c3), and the setting of the temporary coordinate axis in FIG. 18 (b) is the normal button direction. It can be seen that the one is 180 degrees different.
However, the CPU 3-1 performs this search on the polar coordinate conversion image generated in step S1407 (FIG. 19). This is because the search with the original image requires a process of rotating the template according to the hole position, but the template does not need to be rotated during the search on the polar coordinate conversion image. Using the logo feature data acquired and stored in the teaching process as a template, first, the correlation is calculated from the angle at which the logo feature is extracted. This corresponds to calculating the degree of correlation between the detection target button in FIG. 19A and the first template in FIG. 19B. The first template in FIG. 19 (b) corresponds to the candidate 0 degree in FIG. 18 (c1). When a plurality of logo features are registered, a correlation calculation is not performed for each logo feature, but a template data in which a plurality of logo feature data is integrated is generated and a correlation degree is calculated.
Next, the template is shifted in accordance with the number of holes, and the correlation is calculated as the second, third,... Template ((c) → (d) → (e) in FIG. 19, ( c2) → (c3) → (c4)). When shifting the template, the horizontal direction of the polar coordinate conversion image may exceed 360 degrees, but if a template exceeding 360 degrees is arranged from 0 degrees or a polar coordinate conversion image exceeding 360 degrees is created. good.

In the case of non-rotation symmetry, if it is a 2-hole button, it is shifted 180 degrees for a total of 2 times, if it is a 3-hole button, it is shifted 120 degrees for a total of 3 times, and if it is a 4-hole button, it is shifted 90 degrees for a total of 4 times The search is (in the case of FIG. 19).
Further, in the case of omnidirectional mutual rotational symmetry, it is possible to specify that the button hole deviation angle θx is the button direction.
Even if none of the above is true, the number of button direction candidates may be half as compared with the case of non-rotation symmetry. For example, even if it is a four-hole button, if it is known that the logo is a 180-degree rotationally symmetric logo, the angle can be calculated by performing the collation twice as shown in FIG.

Therefore, in step S1409, the CPU 3-1 performs angle calculation and different logo determination as follows.
When the rotational symmetry of the logo when rotating around the axis while maintaining the button hole arrangement is omnidirectional mutual rotational symmetry, in other words, when the button holes are all rotationally symmetric at every matching angle (2 The 180-degree rotational symmetry of the three-hole button, the 120-degree rotational symmetry of the three-hole button, and the 90-degree rotational symmetry logo of the four-hole button) are processed as follows.
The CPU 3-1 rotates the surface image of the detection target button by the button hole deviation angle θx to match the position of the button hole of the detection target button with the position of the button hole in the normal button direction (FIG. 16B). For (c)), calculate the degree of correlation when compared with the logo feature. Using the correlation determination threshold value in step S408 of the teaching process, it is determined whether the calculated degree of correlation exceeds the threshold value.
If the threshold value is exceeded, the logo identity with the sample button is secured, so the CPU 3-1 outputs the button hole deviation angle θx as the button direction of the detection target button (S1410).

When the rotational symmetry has non-rotational symmetry, such as non-rotational symmetry or 180-degree rotational symmetry with a 4-hole button, the following processing is performed.
The CPU 3-1 rotates the surface image of the detection target button by the button hole deviation angle θx to match the position of the button hole of the detection target button with the position of the button hole in the normal button direction (FIG. 16B). (c)), and further rotated by a relative angle of non-rotationally symmetric mutual orientation (for example, 90 °, 180 °, 270 ° in FIG. 22A, 90 ° in FIG. 22C). For each of the images, the degree of correlation is calculated when compared with the logo feature. At this time, the CPU 3-1 determines whether the calculated degree of correlation exceeds the threshold value using the correlation determination threshold value in step S <b> 408 of the teaching process.
If the CPU 3-1 identifies one that exceeds the threshold value, the CPU 3-1 sets the angle θb obtained by adding the rotation angle θm from the state rotated by the button hole deviation angle θx to the button hole deviation angle θx. The button direction of the detection target button is output (see FIG. 21).

  As described above, the angle with respect to the normal button direction is detected from the image captured by the image processing apparatus 3. As described above, this button direction is transmitted to the control unit of the button supply device, and the control unit of the button supply device rotates the locking pin 28a to the button hole position by the motor 61 below the locking pin 28a. After being inserted into the hole, the button is rotated so that the button is arranged in the normal button direction while holding the button. The button is transferred to the button holding mechanism 12b by the turning arm 28 and is set at a sewing position (not shown).

On the other hand, only the correlation degree less than the threshold value can be obtained, or there can be a plurality of angles at which the correlation degree exceeding the threshold value is obtained.
If the CPU 3-1 does not exceed the threshold, and if one that exceeds the threshold is not specified as one, it corresponds to the case where the logo is different, etc., so the angle is not calculated and an abnormality is indicated. Information is output (S1411), and button direction detection is interrupted.

  The button supply device is configured with an exclusion mechanism (not shown) that excludes the button from the conveyance path to the sewing position of the conveyance mechanism. For example, it can be realized by a mechanism for reversing the turning arm 28 and turning the locking pin 28a downward, a mechanism for blowing air to the button, or a combination thereof. The control unit of the button supply device that has received the information indicating abnormality in step S1411 controls the exclusion mechanism to exclude the detection target button from the conveyance path to the sewing position.

According to the above embodiment, the following effects can be obtained.
(1) Since the button direction and button logo can be detected with high accuracy and high efficiency, the button direction is corrected by the button direction control function of the button supply device. It can be automatically fed to the sewing position in line with the normal button direction.
(2) Since it is now possible to detect buttons that are misaligned in the button hole or logo, or have an abnormality in the outer diameter or hole, the button supply device eliminates the abnormal button, so that the abnormal button Supply to the sewing position can be avoided.

1 Camera 2 Illumination Device 3 Image Processing Device 3-1 CPU
3-2 Memory 3-3 Communication port 12b Holding mechanism 13 Button supply unit 13a Bottom surface 13b Passage 13c Unloading port 14 Button rotation conveyance mechanism 14a Button holding unit 21 Button rotation conveyance mechanism 21a Button holding unit 28 Swivel arm 28a Locking pin B Button Ba Button hole α Inclination angle θb Button direction angle θm Rotation angle for logo alignment θx Button hole deviation angle

Claims (13)

In a button direction detection method for detecting a button direction defined by an angle around an axis perpendicular to the front and back surfaces of a button sewn on a sewing product,
When the image processing apparatus calculates the relative angle of the detection target button as the target of the button direction detection with respect to the normal button direction as the button direction of the detection target button,
(1) Obtain a surface image of a sample button that has a button hole and a logo and is provided to teach the normal button direction;
(2) Based on the surface image of the sample button, the normal button direction is detected, the button hole arrangement in the normal button direction, and the rotational symmetry of the logo when rotated around the axis while maintaining the button hole arrangement In addition to specifying the gender, get the logo features in the normal button direction,
(3) Obtain a surface image of the detection target button,
(4) Identify the position of the button hole of the detection target button from the surface image of the detection target button,
(5) Calculate the button hole deviation angle with respect to the button hole in the normal button direction of the button hole of the detection target button,
(6) When the rotational symmetry is omnidirectional mutual rotational symmetry, the surface image of the detection target button is rotated by the button hole deviation angle, and the position of the button hole of the detection target button is the button hole in the normal button direction. For the image matched with the position of the logo, if the degree of correlation when compared with the logo feature is calculated and exceeds a predetermined threshold, the button hole deviation angle is output as the button direction of the detection target button,
(7) When the rotational symmetry has a non-rotational symmetry mutual orientation, the surface image of the detection target button is rotated by the button hole misalignment angle, and the position of the button hole of the detection target button is determined as a regular button. Calculate the degree of correlation when comparing the image with the logo feature for the image matched to the position of the buttonhole in the direction and the image rotated by the relative angle of the non-rotationally symmetric mutual orientation. If one that exceeds a predetermined threshold value is specified, the button angle of the detection target button is determined by adding the rotation angle from the state rotated by the button hole deviation angle to the button hole deviation angle. A method for detecting a button direction, wherein the direction is output as a direction.   The surface image of the sample button is divided into divided areas divided into the same number of angle ranges as the number of button holes around the button center, and based on the degree of correlation when different divided areas are compared with each other, the button center is set as the center of rotation. The button direction detection method according to claim 1, wherein the rotational symmetry of the logo of (2) is specified by determining the rotational symmetry.   The edge image is extracted by differentiating the surface image of the sample button along the circumferential direction around the center of the button, the diameter section where the edge amount is maximum is specified, and the divided area is limited to the diameter section. The button direction detection method according to claim 2, wherein the degree of correlation is calculated.   4. The button direction detection method according to claim 2, wherein the correlation degree is calculated by performing a polar coordinate conversion on the divided areas and comparing the divided areas.   The edge image is extracted by differentiating the surface image of the sample button along the circumferential direction around the center of the button, the diameter section in which the edge amount is maximum is specified, and the above (2) The button direction detection method according to claim 1, further comprising: obtaining a logo feature of the button. The logo feature is memorized by converting polar coordinates around the center of the button,
6. The button direction detection method according to claim 5, wherein, in (6) and (7), the degree of correlation is calculated after performing polar coordinate conversion on an image region to be compared with the logo feature of the surface image of the detection target button. . The acquisition of the surface image of the sample button of (1) is performed by illuminating the surface of the sample button with a predetermined illumination and capturing it with a camera,
2. The button direction according to claim 1, wherein the surface image of the detection target button in (3) is obtained by illuminating the surface of the detection target button with the predetermined illumination and imaging with the camera. Detection method.   Based on the surface image of the sample button, the button hole of the sample button and the button outer diameter are detected. Based on the surface image of the detection target button, the button hole of the detection target button and the button outer diameter are detected. 2. The button direction according to claim 1, wherein when the button outer diameter is different from the button hole of the detection target button and the button outer diameter, information indicating an abnormality is output to interrupt button direction detection. Detection method.   When the predetermined threshold value is not exceeded in (6) and when no one exceeding the predetermined threshold value is specified in (7), information indicating an abnormality is output and the button direction is output. The button direction detection method according to claim 1, wherein the detection is interrupted. A button direction detection device for executing the button direction detection method according to claim 1,
An illumination device, a camera, and an image processing device;
The image processing apparatus includes:
The surface image of the sample button illuminated by the illumination device and imaged by the camera is input, and the above (2) is executed.
A button direction detection device, wherein a surface image of a detection target button illuminated by the illumination device and imaged by the camera is input, and (4) to (7) are executed. A button supply device comprising: the button direction detection device according to claim 10; and a transport mechanism that transports the button to a predetermined supply position.
A button supply device that causes the button direction detection device to detect a button direction of a button conveyed by the conveyance mechanism.   The image processing device detects the button hole and button outer diameter of the sample button based on the surface image of the sample button, detects the button hole and button outer diameter of the detection target button based on the surface image of the detection target button, When the button hole and button outer diameter of the sample button are different from the button hole and button outer diameter of the detection target button, the detection target button is excluded from the transport path to the predetermined supply position of the transport mechanism. It has a mechanism, The button supply apparatus of Claim 11 characterized by the above-mentioned.   When the predetermined threshold value is not exceeded in (6), and when one that exceeds the predetermined threshold value is not specified in (7), the button to be detected is moved to the transport mechanism. The button supply apparatus according to claim 11, further comprising a mechanism for excluding from a conveyance path to a predetermined supply position.