KR20130050420A - A measurement equipment and method for shape measure of curved spring - Google Patents

Abstract

PURPOSE: A curved spring inspection device and an inspection method are provided to improve workability and reliability of inspecting the curved spring. CONSTITUTION: A curved spring inspection device comprises a flat plate type backlight(110), a fixed camera(120), a movable camera(120), 3-axis transporting units(141, 143), and an inspection controller(150). The backlight provides a space where the curved spring is plated and emits lights. The fixed camera is arranged perpendicularly in the upper part of the backlight and photographs the whole images of the curved spring placed on the backlight. The movable camera magnify-photographs partial images of the curved spring. The 3-axis transporting units transport the movable camera in an X-axis, a Y-axis, and a Z-axis. The inspection controller moves the movable camera by controlling the 3-axis transporting units based on the images photographed by the fixed camera and the movable camera and determines the existence of the faulty curved spring by analyzing the images photographed by the movable camera.

Description

A measurement equipment and method for shape measure of curved spring}

The present invention relates to the inspection method and inspection method of the curved spring, and in particular, the inspection work of the curved spring, which is used as a shock absorber, such as a torque converter, which is an automatic transmission and a power transmission part of the engine, automatically by a non-contact method using a vision system. The present invention relates to a curved spring inspection device and inspection method for inspecting.

In general, a shock absorber is used for an automatic transmission of an automobile and a torque converter, which is a power transmission part of an engine, and a curved spring having a circular curved structure is used as a main part of the shock absorber.

The curved spring has the advantage of miniaturization, simplification and performance improvement of components compared to the existing straight spring, and in order to properly implement the required performance, it must be accurately manufactured to have a bent shape with the planned radius in the design stage.

Therefore, the inspection work must be carried out to check whether the fabricated curved spring is made of a structure bent correctly to the intended radius of the designer. However, due to the structural characteristics of the curved spring, there is no proper inspection device. to be.

However, the conventional inspection method is a manual method using a measuring jig of a round shape, the measurement operation is not easy, of course, accurate measurement is difficult, there is a problem that the measurement reliability is low due to the severe deviation depending on the measurer.

The present invention has been made in consideration of the above problems, and an object of the present invention is to automatically inspect the failure of the curved spring using a vision system in performing the inspection operation of the curved spring, through this curve It is to provide a curved spring inspection device and inspection method that can improve the workability and reliability of the inspection work of the type spring.

Curved spring inspection apparatus of the present invention to achieve the object as described above and to perform the problem for eliminating the conventional drawbacks provides a space in which the curved spring is placed, the backlight of the flat structure to emit light; A fixed camera arranged to be positioned at a vertical upper portion of the backlight to capture the entire image of the curved spring placed on the backlight; A mobile camera arranged to be positioned at a vertical upper portion of the backlight to enlarge and photograph a local image of a curved spring placed on the backlight; A three-axis transfer unit which transfers the mobile camera in X, Y, and Z axis directions; And an inspection controller for controlling a three-axis transfer unit based on the images photographed by the fixed camera and the mobile camera to move the mobile camera, and analyzing the image taken by the mobile camera to determine whether the curved spring is defective. Characterized in that configured.

At this time, the backlight is preferably composed of a red LED.

Meanwhile, the curved spring inspection method of the present invention photographs the entire image of the curved spring placed on the backlight using a fixed camera, and the inspection controller detects the coordinates of the zero-volume pitch point of the curved spring from the captured image. Step S100; The moving camera is moved to the zero-volume pitch point detected in step S100 to take a local image of the zero-volume, the zero-volume pitch point and the left angle detected from the photographed image, and the reference outer radius of the curved spring input in advance. Setting a virtual center point by using a step (S200); Analyzing the virtual center point set in the step S200 and the image taken by the mobile camera to detect the next number of pitch points, and then repeats the process of detecting the next number of turns pitch point using the detected next number of pitch points and the virtual center point 0 Detecting each number of winding pitch points other than the number of turns (S300); Deriving an equation of a circle using the number of turns pitch points detected in the step S300 and deriving an outer radius center point of the curved spring using the derived circle equation (S400); Move the camera to each number of pitch points detected in the previous step. Move the camera and retake each number of pitch points. Re-detect the pitch point of each number of windings using the re-photographed number of images and the outer radius center point detected in the previous step. Step (S500); Deriving an equation of a circle using a pitch point of each number of turns redetected in the step S500, and again deriving an outer radius center point of the curved spring using the derived circle equation (S600); Check whether the outer radius center point derived in step S600 and the outer radius center point immediately derived are within a preset error range, and if the two outer radius center points are within the error range, the distance between the final outer radius center point and each winding pitch point Calculating and comparing the calculated distance between the reference outer radius of the corresponding curved spring input in advance to determine whether the curved spring is defective (S700); And if the two outer radius center points are not within the error range in step S700, repeating steps S500 to S700 (S800).

According to the present invention having the characteristics as described above, by taking an image of the curved spring placed on the backlight, and by analyzing the photographed image to determine whether the curved spring is defective, work on the inspection operation of the curved spring This has the effect of improving performance and reliability.

1 is a front view showing the structure of a curved spring inspection apparatus according to the present invention,
2 is a plan view showing the structure of a curved spring inspection apparatus according to the present invention,
3 is a block diagram showing a connection structure between an inspection controller and another device according to the present invention;
4 is a flowchart showing a process sequence of the inspection method according to the present invention;
5 is an exemplary view illustrating a process of detecting a zero-volume pitch point by using an image acquired by a fixed camera.
6 is an image of volume 0 pitch point photographed by a mobile camera;
7 is an exemplary view illustrating a process of detecting a seat angle;
8 is an exemplary view illustrating a process of detecting a pitch point by analyzing a rotated image;
9 is an image taken by the mobile camera moving to one pitch point;
10 is an exemplary view showing a redetection principle of each number of winding pitch points;
11 is an image showing the outer radius measurement and the measurement of the distance and the angle between the center and the end of the number of turns and the acceptance determination through the display device.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 is a front view showing the structure of the curved spring inspection apparatus according to the present invention, Figure 2 is a plan view showing the structure of the curved spring inspection apparatus according to the present invention.

The curved spring inspection apparatus according to the present invention includes a backlight 110, a fixed camera 120, a mobile camera 130, three-axis transfer units 141, 142, 143, and an inspection controller 150.

The backlight 110 provides a space in which the curved spring to be measured is placed and emits light of the placed curved spring to provide an environment in which the curved spring can be photographed more clearly. Meanwhile, the backlight 110 is a light emitting panel having a flat panel structure. Since the backlight 110 is a well-known technique used in a computer monitor or a TV, a detailed description of the structure of the backlight 110 will be omitted.

However, in the case of the backlight 110 according to the present invention, it is preferable to configure the backlight 110 by using a red LED for accurately acquiring data on the shape of the curved spring using the cameras 120 and 130.

The fixed camera 120 is spaced apart from the backlight 110 at a vertical upper portion of the backlight 110 to capture the entire image of the curved spring placed on the backlight 110.

The mobile camera 130 is disposed to be spaced apart from the backlight 110 in a vertical upper portion of the backlight 110, and moves under the control of the inspection controller 150 to capture a local image of the curved spring.

The fixed camera 120 and the mobile camera 130 may be configured as a black and white camera.

The three-axis transfer unit (141, 142, 143) moves the mobile camera 130 under the control of the inspection controller 150, the X-axis transfer unit 141, the Y-axis transfer unit 142 and Z-axis transfer unit ( 143) is configured to freely move the mobile camera 130 in the X / Y / Z axis direction. Each axis transfer unit (141, 142, 143) is provided with a feed motor (M), and an encoder (E) for detecting the rotational speed of the feed motor (M), the inspection controller 150 accurately recognizes the position of the mobile camera 130, Is configured to control, the X-axis transfer unit 141 extends in the horizontal direction of the backlight 110, the Y-axis transfer unit 142 extends in the longitudinal direction of the backlight 110, Z-axis transfer unit 143 is disposed in a structure extending in the vertical direction from the backlight 110. Since the three-axis transfer unit (141, 142, 143) is a well-known technique that is used in various industries, a more detailed description thereof will be omitted.

3 is a block diagram showing a connection structure between an inspection controller and another device according to the present invention.

The inspection controller 150 moves the mobile camera 130 by controlling the three-axis transfer unit 141, 142, 143 based on the images captured by the fixed camera 120 and the mobile camera 130, and the mobile camera 130. By analyzing the image photographed by using the number of turns pitch point and the outer radius of the curved spring to determine whether the corresponding curved spring is defective.

The inspection controller 150 is connected to the fixed camera 120 and the mobile camera 130 through the image interface to control the fixed camera 120 and the mobile camera 130, and transmits images captured by the two cameras. Receiving, the backlight 110 is connected to the lighting controller to control the backlight 110 according to the progress of the inspection operation, the transfer motor (M) of each axis transfer unit constituting the three-axis transfer unit (141, 142, 143) and The encoder E is connected to the motor control interface to control the motor, and the test result made by the test controller 150 is displayed on the display device.

It will be described how to check whether the curved spring is defective using the curved spring inspection device configured as described above. Unless otherwise specified in the following description, "the number of turns" refers to the number of turns positioned at the center of the image as a photographing standard of the mobile camera, and "next turns" means the number of turns after the number of turns is detected. As a result, the "next volume" is changed to "the number of volumes" as the inspection step progresses, and a new "next volume" is displayed again.

In addition, the above-mentioned pitch point means one point located in the outermost part of each turn, and the definition of such a pitch point is the same also in the following description.

Figure 4 shows a flow chart showing the process sequence of the inspection method according to the present invention.

Curved spring inspection method of the present invention implemented using the inspection device configured as described above is photographing the entire image of the curved spring placed on the backlight 110 using the fixed camera 120, the inspection controller 150 Detecting coordinates of the zero pitch point of the curved spring from the captured image (S100); The moving camera 130 is moved to the zero pitch point detected in step S100 to take a local image of the zero volume, and the zero volume pitch and the left angle and the curved spring input previously detected from the photographed image. Setting a virtual center point using a reference outer radius (S200); Analyzing the virtual center point set in step S200 and the image photographed by the mobile camera 130 to detect the next number of pitch points, and detecting the next number of pitch points using the detected next number of pitch points and the virtual center point. Iteratively detecting each number of pitch points other than 0 (S300); Deriving an equation of a circle using the number of turns pitch points detected in the step S300 and deriving an outer radius center point of the curved spring using the derived circle equation (S400); Move the camera 130 to each of the number of winding pitch points detected in the previous step and retake each number of winding pitch points, and use the re-photographed number of winding images and the outer radius center point detected in the previous step to determine the pitch of each number of turns. Re-detecting (S500); Deriving an equation of a circle using a pitch point of each number of turns redetected in the step S500, and again deriving an outer radius center point of the curved spring using the derived circle equation (S600); Check whether the outer radius center point derived in step S600 and the outer radius center point immediately derived are within a preset error range, and if the two outer radius center points are within the error range, the distance between the final outer radius center point and each winding pitch point Calculating and comparing the calculated distance between the reference outer radius of the corresponding curved spring input in advance to determine whether the curved spring is defective (S700); And when the two outer radius center points are not within the error range in step S700, repeating steps S500 to S700 (S800).

5 illustrates an example of a process of detecting a zero-volume pitch point by using an image acquired by a fixed camera.

When the curved spring to be measured is placed on the backlight 110 and the inspection apparatus is executed, the moving camera 130 moves to the origin position, and the operator inspects in advance the ideal reference outer radius of the curved spring to be inspected. Will be entered into the device. Meanwhile, the inspection controller 150 determines whether the curved spring is defective by comparing the reference outer radius input in advance with the outer radius calculated through the inspection operation.

The step S100 is a step of detecting a zero-pitch pitch point of the curved spring placed on the backlight 110.

Since no means are provided for aligning the position of the curved spring on the backlight 110, the attitude and position of the curved spring lying on the backlight 110 are different each time. Therefore, the entire image of the curved spring placed on the backlight 110 is photographed using the fixed camera 120, and the zero-pixel pitch point is detected by analyzing the image photographed by the fixed camera 120.

More specifically, the black and white image information photographed by the fixed camera 120 may represent a pixel as a value of contrast (brightness), and in the case of 8 bits, the pixel may be represented using a contrast value in a range of 0 to 255. Can be represented. That is, 255 is the pixel having the brightest color (white) and 0 is the pixel having the darkest color (black). Therefore, since the curved spring in the image captured by the camera is represented by pixels having dark colors, the black color of the image captured by the fixed camera 120 is filtered to make the black and white distinction more apparent, and then the dark color in the image is filtered. The zero pitch point is detected by finding the pixel to have.

In the case of FIG. 5, a method of detecting the zero pitch point by analyzing the contrast value of each pixel from the bottom of the image to the left to the right of the image is illustrated. The first detected pixel recognition value (value smaller than the contrast value of the backlight 110) is detected as the zero pitch value.

On the other hand, if the center position of the fixed camera 120 is set to match the center positions of the three-axis transfer unit (141, 142, 143) and the mobile camera 130, the actual detection position of the curved spring is as follows [Equation 1] and [Vertical 2] ] Can be determined.

Pixel width size of fixed camera 120: Fix_Image_Width (X-axis)

Pixel height size of fixed camera 120: Fix_Image_Height (Y-axis)

Unit of measurement of the fixed camera 120: Fix_image_Unit

Actual center X position of fixed camera 120: Fix_Camera_Center_X

Actual center Y position of fixed camera 120: Fix_Camera_Center_Y

Measurement product detection of fixed camera 120 X position: Fix_Image_Edge_X

Measurement product detection of fixed camera 120 Y position: Fix_Image_Edge_Y

Actual X position of the measured product:

Real_X = Fix_Camera_Center_X- (Fix_Image_Width × 0.5-Fix_Image_Edge_X) × Fix_image_Unit ------- [Equation 1]

Actual Y position of the measured product:

Real_Y = Fix_Camera_Center_Y- (Fix_Image_Height × 0.5-Fix_Image_Edge_Y) × Fix_image_Unit ------- [Equation 2]

The inspection controller 150 controls the three-axis transfer units 141, 142, and 143 using the coordinates of the zero pitch point of the actual curved spring calculated by the above equation to move the mobile camera 130 to the zero pitch point. It becomes possible.

6 illustrates an image of volume 0 pitch point photographed by a mobile camera.

The step S200 is a step of setting the left face angle and the virtual center point of the detected curved spring. In step S200, the inspection controller 150 controls the three-axis transfer units 141, 142, and 143 using the coordinates of the zero-pitch point detected in step S100, so that the center of the mobile camera 130 is located on the vertical upper portion of the zero-pitch point. The mobile camera 130 is moved to be positioned, the local image including the zero volume is photographed using the mobile camera 130 which has been moved, and the inclination (left angle) of the left side is obtained from the captured image, and the left angle The virtual center point is set using the volume 0 pitch point and the reference outer radius input in advance.

Typically, an ideal curved spring is formed such that the seating surface coincides with the normal through the zero volume pitch point. Therefore, after detecting the coordinates of volume 0 pitch point, detecting the inclination angle (left angle) of the left surface, and using the coordinates of the volume 0 pitch angle, the surface angle and the reference outer radius input in advance, the virtual center point of the curved spring Can be calculated.

7 is an exemplary view illustrating a process of detecting a seat angle.

7 is an image obtained by dividing the actual obtained image by the product recognition setting value, and the image is filtered in black and white. Since the end of the initial volume 0 (the volume 0 pitch point) is located at the center of the transfer camera, the volume 0 pitch is displayed in the lower right area. By analyzing the pixel information in the same manner as the detection of the point, a plurality of detection points located on the left surface can be obtained.

By applying the detected plurality of detection points to Equations 3 to 8 below, the coordinates of the left angle and the virtual center point can be obtained.

Pixel Width Size of Move Camera 130: Move_Image_Width (X-axis)

Pixel width of the moving camera 130: Move_Image_Height (Y-axis)

Measurement unit of the moving camera 130: Move_Image_Unit

Moving unit X axis Current position: X_Unit_Cureent_Post

Moving unit Y axis Current position: Y_Unit_Crrrent_Post

Detection X position of moving camera 130: Move_Image_Edge_X

Detection Y position of moving camera 130: Move_Image_Edge_Y

Actual X position of the detection point:

Real_X = X_Unit_Cureent_Post- (Move_Image_Width × 0.5-Move_Image_Edge_X) × Move_Image_Unit ------- [Equation 3]

Actual Y position of the detection point:

Real_Y = Y_Unit_Crrrent_Post- (Move_Image_Height × 0.5-Move_Image_Edge_Y) × Move_Image_Unit ------- [Equation 4]

Applying the least squares method to the coordinates of the detected n detection points, the optimal left-handed linear equation y = ax + b passing through the n coordinates can be obtained as follows.

Detected actual Real_X coordinate position: x1, x2, x3 ..... xn

Actual Real_Y coordinate position detected: y1, y2, y2 ..... yn

-------- [수식5]

-------- [Equation 5]

Left angle (Start_Angle) is

Start_Angle = tan ^-1 (a) ------- [Equation 6]

.

The virtual center point can be obtained using the following Equations 7 and 8 by using the coordinates of the seat surface angle, the zero pitch point, and the reference outer radius input in advance.

Volume 0 end coordinate X: Start_Post_X

Volume 0 end coordinates Y: Start_Post_Y

Base outer radius of curved spring: Base_Out_R

Outer Radius Center Coordinate X:

Out_R_Center_X = Base_Out_R × cos (Start_Angle) + Start_Post_X ------- [Equation 7]

Outer radius center coordinate Y:

Out_R_Center_Y = Base_Out_R × sin (Start_Angle) + Start_Post_Y ------- [Equation 8]

The step S300 is a step of detecting a pitch point for each number of turns of the curved spring.

The step S300 may include rotating the image photographed through the step S200 such that the first centerline is parallel to the Y axis (S310); The inspection controller 150 analyzes the image rotated through the previous step and recognizes the peak point whose Y-axis coordinates increase and then decreases again as the inflection point, detects this inflection point as the next number of turns pitch point, and detects the detected pitch point. Converting to coordinates (S320); Photographing another local image by moving the moving camera 130 to actual coordinates of the pitch point detected in step S320 (S330); Rotating the image photographed in step S340 so that a next winding centerline having a pitch point to be detected is placed in parallel with the Y axis (S340); And repeating steps S320 to S340 until detecting a pitch point for each number of turns of the curved spring (S350).

The step S310 is a step of rotating the image so that the next winding centerline lies parallel to the Y axis for easy detection of the next winding number pitch point.

In step S310, the next winding center line is positioned to be Y-axis parallel by rotating the image using the left angle detected in step S200.

More specifically, in step S310, the image rotation angle is obtained by using Equation 9 below using the left angle, and the center of the first volume, which is next to volume 0, is rotated with the Y axis by rotating the image photographed in step S200 to the image rotation angle. It will be placed in parallel.

Rotation angle = 90-Left angle ------- [Equation 9]

8 illustrates an example of a process of detecting a pitch point by analyzing a rotated image.

In step S320, the inflection point in the image is detected by analyzing the rotated image in step S310, and the detected inflection point is detected as the next number of peaks.

On the other hand, the rotation of the image is made around the corresponding number of pitch points, the winding pitch point is located in the center of the image. Therefore, as shown in FIG. 8, the contrast value of each pixel is analyzed from the center of the image to the right from the top to the bottom of the image to derive a plurality of detection points. In this case, the inflection point is detected, and when two or more inflection points are detected, the inflection point closest to the pitch point of the number of turns is selected and detected as the next number of turns pitch point.

Meanwhile, in order to move the moving camera 130 to the detected next number of pitch points, actual coordinates of the next number of pitch points are required, and the actual coordinates of the pitch points are obtained through Equations 10 and 11 below. Can be.

Detection angle: Rotate_Angle

Rotation angle: 90-Rotate_Angle

Pitch end coordinates detected in the rotated image X: FindEdgePoint_X

Pitch end coordinate detected in the rotated image Y: FindEdgePoint_Y

Pitch end coordinates of the image reduced to the original image X: Move_Image_Edge_X (= coordinate of the moving camera of Equation 3)

Pitch end coordinates of the image reduced to the original image Y: Move_Image_Edge_Y (= coordinate of moving camera of Equation 4)

Move_Image_Edge_X = Move_Image_Width × 0.5 + (FindEdgePoint_X-Move_Image_Width × 0.5) × cos (Rotate_Angle-90.0) + (FindEdgePoint_Y-Move_Image_Height × 0.5) × sin (Rotate_Angle-90.0) ------- [Equation 10]

Move_Image_Edge_Y = Move_Image_Height × 0.5 + (FindEdgePoint_X-Move_Image_Width × 0.5) × sin (Rotate_Angle-90.0) + (FindEdgePoint_Y-Move_Image_Height × 0.5) × cos (Rotate_Angle-90.0) ------- [Equation 11]

9 shows an image captured by a mobile camera by moving to one pitch point.

In step S330, the moving camera 130 is moved to the next number of turns pitch point detected in step S320, and a local image is photographed.

The step S340 is to rotate the image taken in step S330 so that the next winding centerline having the pitch point to be detected is placed in parallel with the Y axis. The step S340 may include calculating a tilt angle of the pitch number of the number of turns and the pitch angle of the number of turns from the virtual center point located at the center of the photographed image (S341); And rotating the image using the inclination angle such that the next winding center line is parallel to the Y axis (S342).

Meanwhile, in step S341, the rotation angle of the image is calculated by using the corresponding number of pitch points and the virtual center line calculated in step S200, and more specifically, it can be obtained by using Equation 12 below.

n Volume Pitch End Detection Position: Circle_Edge_n (an, bn)

Outer radius center coordinates: Out_R_Center (Cx, Cy)

Rotation angle: Rotate_Angle = tan ^-1 ((an-Cx) / (bn-Cy) ------- [Equation 12]

In the step S342 by rotating the image by using the inclination angle (rotation angle) of the number of winding pitch point calculated in step S341 to position the next winding centerline parallel to the Y axis.

The step S350 is to detect the next number of pitch points through the analysis of the image rotated through the previous step (step S320), the step of moving the moving camera 130 to the next number of turns pitch point detected (S330 step), The rotation of the image for detecting the next number of turns pitch point (step S340) is repeated until the pitch point for each number of turns of the curved spring is detected. On the other hand, since the inflection point is not detected because there is no next number in the photographed image, if the inflection point is not detected through the analysis of the image, it is recognized as the last number and the process of detecting the pitch point is terminated.

The step S400 is a step of deriving an equation of a circle using coordinates of all pitch points detected as each number of pitch points, and calculating an outer radius center point of the curved spring using the derived circle equation.

Using the number of turns pitch point detected through the step S300 and the following [Equation 13] to [Equation 17], it is possible to derive the equation of the optimal circle passing through each number of turns pitch point and the outer radius center point of the curved spring have.

Pitch end detection position: CEn CE ₁ (a ₁ , b ₁ ), CE ₂ (a ₂ , b ₂ ), ... CE _1n (a _n , b _n )

The center of the _{circle: Center Center_X = (a 1 +} a 2 ···· + a n) / n ------- [ Equation 13]

Center_Y = (b ₁ + b ₂ ... + b _n ) / n ------- [Vertical 14]

Distance from center to pitch end: l _k

------- [수식15]

------- [Equation 15]

------- [수식16]Radius: R

------- [Equation 16]

------- [수식17]Equation

------- [Equation 17]

Step S500 redetects the pitch point of each number of turns using the previously derived outer radius center point, derives an equation of a circle using the pitch point of each number of turns again, and curves using the derived equation of the circle. The new radial center point of the outer spring is derived.

The step S500 may include photographing a local image for each number of turns by sequentially moving the moving camera 130 from the last detected number 0 pitch point to the number of each pitch number detected last (S510). When the image of the number of turns is taken through the step S510, the inspection controller 150 calculates an inclination angle with respect to the number of turns pitch point by using the last number of turns detected and the outer radius center point calculated last. Rotating the image of the number of turns so that the centerline of the number of turns is parallel to the Y axis using the calculated tilt angle (S520); The inspection controller 150 analyzes the image rotated through the previous step, selects a pixel having the largest Y-axis coordinate value among the plurality of detection points detected in the image, redetects it to the corresponding number of pitch points, and redetects Converting the pitch point into actual coordinates (S530); Comparing coordinates of the corresponding number of winding pitch points detected in the step S530 with coordinates of the corresponding number of winding pitch points last detected (S540); If the coordinates of the two pitch points are the same in step S540, moving the moving camera 130 to the next number of pitch points to take a local image for the next number of turns (S550); If the coordinates for the two pitch points are not the same in step S540, by moving the moving camera 130 to the actual coordinates for the pitch point re-detected in step S530 to retake the image for the number of times, the previous detection Recomputation of the inclination angle for the number of turns pitch point using the corresponding number of turns pitch point and the outer radius center point calculated by the previous operation, and the center line of the number of turns is parallel to the Y axis using the recomputed inclination angle. After rotating the re-photographed image to be placed, the steps S530 to S550 are repeated, but are repeated until the two coordinates for the pitch point are the same (S560).

In the step S510, the mobile camera 130 is sequentially transferred to the number 0 pitch point and each number pitch point detected in steps S100 and S300 during the initial execution of the step S500. When the step S500 is executed again, the last step is performed. The moving camera 130 is moved by using the zero-volume pitch point and each number-pitch point detected in order to take an image of each number of images.

The step S520 is executed when an image of each number is taken in the process of capturing the image through the step S510 to rotate the image for redetection of the corresponding number of pitch points.

In the step S520, the rotation angle of the image is derived by calculating the inclination angle of the number of turns pitch points using the last detected number of turns pitch points and the outermost radial center point derived last. By rotating the image of the number of turns using an angle, the number of turns centerline is positioned to be parallel to the Y axis.

On the other hand, the derivation of the image rotation angle as described above may be derived by the same method as in [Equation 12].

Fig. 10 shows an exemplary view showing the re-detection principle of each turn pitch point.

Step S530 is a step of re-detecting the corresponding number of pitch points from the image rotated through the previous step, and converting the re-detected pitch point to the actual coordinates.

In step S530, as shown in FIG. 10, the corresponding left pitch part and the right part are set as the inspection area based on the center part of the image in consideration of the fact that the corresponding number of pitch points is always located in the center of the image.

On the other hand, the detection of the number of turns pitch point analyzes the pixel information from the top to the bottom of the inspection area to detect a plurality of detection points, wherein the detection point having the largest Y-axis coordinate value among the plurality of detection points corresponding to the number of turns pitch The point is detected. The detected number of turns pitch points is converted into actual coordinates in the same manner as in [Formula 10] and [Formula 11].

In step S540, the corresponding number of turns pitch point detected in step S530 and the corresponding number of turns pitch point detected last are identified.

In step S550, if it is determined that the two pitch points coincide with step S540, the process returns to step S510 to move and photograph the moving camera 130 to the next turn.

In step S560, when it is determined in step S540 that the two pitch points do not coincide with each other, the detection of the corresponding pitch point is performed.

In the step S560, the moving camera 130 is photographed by moving the moving camera 130 again to the actual coordinates of the corresponding number of winding pitch points detected last, and the corresponding number of winding pitch points is detected again in the same manner as the steps S520 and S530, and again. Check whether the detected number of turns pitch points coincide with the last number of turns pitch point detected, and if the two pitch points match, the process returns to step S510 to redetect the next number of turns pitch point, and the two pitch points coincide. Otherwise, steps S530 to S550 are repeated until the two coordinates of the corresponding number of pitch points coincide.

The step S600 is to derive the circle equation and the outer radius center point by using the number of turns pitch point detected through the step S500 and [Equation 13] to [Equation 17].

In step S700, the newly-derived outer radius center point and the immediately-derived outer radius center point in step S600 are checked to be within a preset error range, and if the two center points are within the error range, it is determined that an accurate center position is calculated. The distance between the center of the outer radius and the number of turns pitch point is calculated, and it is determined whether the curved spring is defective by comparing the calculated distance and the reference outer radius of the corresponding curved spring previously input. Meanwhile, the error range is input by the operator in advance to the inspection device.

For reference, FIG. 11 illustrates an image of measuring the outer radius, measuring the distance and angle between the center and the end of the number of turns, and showing the summation determination through the display device.

In step S800, if it is confirmed in step S700 that the two outer radius center points are not within the error range, steps S500 to S700 are repeated to more accurately detect the outer radius center point.

As described above, according to the present invention, the image of the curved spring is photographed by the fixed camera 120 and the mobile camera 130, and it is determined whether the curved spring is defective by analyzing the same. There is an advantage that can determine whether or not.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims and their equivalents. Of course, such modifications are within the scope of the claims.

Description of the Related Art
110: backlight 120: fixed camera
(130): mobile camera (141): X axis transfer unit
(142): Y-axis transfer unit (143): Z-axis transfer unit
150: inspection controller

Claims (6)

A backlight 110 providing a space in which the curved spring is placed and emitting light;
A fixed camera 120 disposed to be positioned at a vertical upper portion of the backlight 110 to capture an entire image of a curved spring placed on the backlight 110;
A mobile camera 130 arranged to be positioned at a vertical upper portion of the backlight 110 to enlarge and photograph a local image of a curved spring placed on the backlight 110;
3-axis transfer units (141, 142, 143) for transferring the mobile camera 130 in the X-axis, Y-axis and Z-axis directions; And
The mobile camera 130 is moved by controlling the three-axis transfer units 141, 142, and 143 based on the images captured by the fixed camera 120 and the mobile camera 130, and the image captured by the mobile camera 130 is moved. Curved spring inspection device, characterized in that consisting of the inspection controller 150 to determine whether the failure of the curved spring by analyzing. The method of claim 1,
The backlight 110 is a curved spring inspection device, characterized in that consisting of a red LED. Photographing the entire image of the curved spring placed on the backlight 110 using the fixed camera 120, and the inspection controller 150 detecting coordinates of the zero-volume pitch point of the curved spring from the captured image. (S100);
The moving camera 130 is moved to the zero pitch point detected in step S100 to take a local image of the zero volume, and the zero volume pitch and the left angle and the curved spring input previously detected from the photographed image. Setting a virtual center point using a reference outer radius (S200);
Analyzing the virtual center point set in step S200 and the image photographed by the mobile camera 130 to detect the next number of pitch points, and detecting the next number of pitch points using the detected next number of pitch points and the virtual center point. Iteratively detecting each number of pitch points other than 0 (S300);
Deriving an equation of a circle using the number of turns pitch points detected in the step S300 and deriving an outer radius center point of the curved spring using the derived circle equation (S400);
Move the camera 130 to each of the number of winding pitch points detected in the previous step and retake each number of winding pitch points, and use the re-photographed number of winding images and the outer radius center point detected in the previous step to determine the pitch of each number of turns. Re-detecting (S500);
Deriving an equation of a circle using a pitch point of each number of turns redetected in the step S500, and again deriving an outer radius center point of the curved spring using the derived circle equation (S600);
Check whether the outer radius center point derived in step S600 and the outer radius center point immediately derived are within a preset error range, and if the two outer radius center points are within the error range, the distance between the final outer radius center point and each winding pitch point Calculating and comparing the calculated distance between the reference outer radius of the corresponding curved spring input in advance to determine whether the curved spring is defective (S700); And
If the two outer radius center point in the step S700 is not within the error range, the step of repeating the steps S500 to S700 (S800), characterized in that the curved spring inspection method. The method of claim 3, wherein the step S300,
Rotating the image taken through the step S200 step 1 so that the center line is placed parallel to the Y axis (S310);
The inspection controller 150 analyzes the image rotated through the previous step and recognizes the peak point whose Y-axis coordinates increase and then decreases again as the inflection point, detects this inflection point as the next number of turns pitch point, and detects the detected pitch point. Converting to coordinates (S320);
Photographing another local image by moving the moving camera 130 to actual coordinates of the pitch point detected in step S320 (S330);
Rotating the image photographed in step S340 so that a next winding centerline having a pitch point to be detected is placed in parallel with the Y axis (S340); And
Step S320 to step S340 is characterized in that for repeating the step of detecting the pitch point for each number of turns of the curved spring (S350) characterized in that it consists of. The method of claim 4, wherein the step S340,
Calculating a tilt angle of the pitch number of the number of turns located at the center of the photographed image and the pitch number of the number of turns from the virtual center point (S341); And
And a step (S342) of rotating the image using the inclination angle so that the next winding center line is parallel to the Y axis. The method of claim 3, wherein the step S500,
Step S510 of photographing a local image for each number of turns by sequentially moving the moving camera 130 from the last detected number 0 pitch point to each number of pitch number detected last (S510);
When the image of the number of turns is taken through the step S510, the inspection controller 150 calculates an inclination angle with respect to the number of turns pitch point by using the last number of turns detected and the outer radius center point calculated last. Rotating the image of the number of turns so that the centerline of the number of turns is parallel to the Y axis using the calculated tilt angle (S520);
The inspection controller 150 analyzes the image rotated through the previous step, selects a pixel having the largest Y-axis coordinate value among the plurality of detection points detected in the image, redetects it to the corresponding number of pitch points, and redetects Converting the pitch point into actual coordinates (S530);
Checking whether the corresponding number of winding pitch points detected in the step S530 and the corresponding number of winding pitch points last detected coincide (S540);
If the two pitch points coincide in step S540, the process returns to step S510 to move the moving camera 130 to the next turn pitch point so that a local image of the next turn is taken (S550);
If the two pitch points do not match in step S540, the moving camera 130 is moved to the actual coordinates of the pitch point redetected in step S530 to retake an image of the number of times, and the number of the last number of detected turns Using the pitch point and the outermost radius center computed last, recomputation of the inclination angle with respect to the number of turns pitch point, and using the recomputed inclination angle, retaken so that the centerline of the number of turns is parallel to the Y axis. After rotating the image, repeating steps S530 to S550, repeating until the two coordinates for the pitch point is the same (S560), characterized in that the curved spring inspection method.

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