JP2867247B2 - Upper edge detection method of transparent or translucent wrap film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera for photographing an upper edge of a wrap film by a camera to check whether a transparent or translucent wrap film wound around a bottle body is properly wound. It relates to a method of detecting by processing.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 6-186002 discloses a method for inspecting the appearance of a label affixed to the body of a bottle. In this label appearance inspection method, a camera is arranged on one side with a bottle interposed, and an illuminating device is arranged opposite to the other side, the bottle is illuminated from the opposite side of the camera, the label is imaged as a shadow, and the outline portion of the shadow image is Image processing for emphasizing and extracting only the label is performed, and it is determined whether or not the label has a poor appearance (turning over, tearing, or the like) based on the extracted label outline portion.

[0003]

However, this method is
This is based on the fact that the light from the lighting device is transmitted through the bottle body and shielded from light on the label.In the case of a transparent or translucent wrap film, the light is transmitted in the same way as the bottle body. The difference between the main body and the outline of the wrap film is not apparent on the image, and the outline of the wrap film cannot be detected clearly.

Therefore, when detecting the outline of a transparent or translucent wrap film wound around a bottle body, a reflected light method is better than a transmitted light method. However, even if the reflected light method is adopted, the reflection mainly includes internal reflection of scattered light in which light from the projector 1 is scattered by the wrap film 2 as shown in FIG. There are three types of reflection: the internal reflection of direct light that is transmitted once through the film 2 and the bottle 3 and reflected on the inner surface of the bottle, and the external reflection of direct light that directly reflects the outer surface (glass surface) of the bottle 3 as shown in FIG. Yes, these three types of reflected light are
Light enters. It is important from the viewpoint of ease of image processing to employ a method in which the outline of the upper edge 2a of the wrap film 2 appears as clearly as possible in the image captured by the camera 4 as compared with other images. In this regard, it is necessary to consider the above three types of reflection and to prevent unnecessary reflected light from entering the camera 4 as much as possible. If there is a sculpture on the outer surface of the bottle, the reflection from the sculpture must also be considered.

[0005] Furthermore, since the wrap film is wound in a circular shape and wound around the outer surface of the body, if the directional direction of the camera is vertically inclined toward the upper edge of the wrap film, the upper edge of the wrap film will not move. Is distorted in the camera image and appears as a curved line, and the height and inclination of the upper edge cannot be calculated accurately. Therefore, the direction of the camera should be as horizontal as possible to the upper edge of the wrap film. Is preferred.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a transparent or translucent wrap film with a contour line at the upper edge so that it can be clearly distinguished from other images on a camera image. An object of the present invention is to make it easier to detect the upper edge of a wrap film while minimizing the influence of the curvature of the outer surface of the torso, and to accurately calculate the height and inclination of the wrap film.

[0007]

According to the present invention, there is provided a method of detecting the upper edge of a transparent or translucent wrap film wound around the outer periphery of a bottle by a camera and detecting the upper edge by electrical image processing. As shown in FIG. 4, the camera 4 is moved above the wrap film 2 for a bottle in which the height of the upper edge 2 a of the wrap film 2 is equal to or less than the height of the boundary line between the body 3 a and the shoulder 3 b of the bottle 3. At the same height as the edge 2a, the projector 1 is placed on the same side as the camera 4 with the wrapping film 2.
Is set at a position lower than the height of the upper edge 2a of the wrap film 2 and is projected obliquely upward toward the upper edge 2a of the wrap film 2 so that the illuminated upper edge 2a of the wrap film 2 is reflected by the reflected light. An image is taken by the camera 4.

When the camera 4 and the projector 1 are arranged in relation to the upper edge 2a of the wrap film 2 as shown in FIG. Since the reflected light on the part and the outer surface of the shoulder is directed upward and hardly enters the camera 4, the upper edge 2a can be detected. However, as shown in FIG. 5, when the camera 4 and the projector 1 are arranged in a reverse relationship to that in FIG. 4 and the directional direction of the projector 1 is a depression angle, the reflected light at the vertical portion of the outer surface of the body of the bottle 1 is reflected. However, since the light enters the camera 4 horizontally or slightly downward, it is impossible to detect the upper edge 2a.

Further, as shown in FIG.
In the case of a bottle having an engraved portion 3c on the outer surface of the bottle above the upper edge 2a, the camera 4 is installed at substantially the same height as the upper edge 2a of the wrap film 2, and the projector 1 is It is installed at a position higher than the height of the upper edge 2a of the wrap film 2 on the same side, and the light is projected obliquely downward toward the upper edge 2a of the wrap film 2 so that the light is projected on the wrap film 2 being illuminated. The camera 4 captures an image of the edge 2a using reflected light.

When the camera 4 and the projector 1 are arranged in relation to the upper edge 2a of the wrap film 2 as shown in FIG. Since the reflected light from the portion 3c is directed downward and hardly enters the camera 4, the upper edge 2a can be detected. However, as shown in FIG.
When the directional direction of the projector 1 is an elevation angle, the engraved portion 3 on the outer surface of the body of the bottle 1
Since the reflected light at c enters the camera 4 in a horizontal or slightly downward direction, the upper edge 2a cannot be detected.

Since the bottle body is curved in a circular shape, two projectors are arranged on both sides of one camera as shown in FIG. good.

Since the bottle body is curved in a circular shape, if the directional direction of the camera is vertically inclined toward the upper edge of the wrap film, the upper edge is distorted in the image of the camera and is curved. Appears as. Therefore, after extracting the contour line of the upper edge of the wrap film from the image of the camera, the height of the contour line is determined by the diameter D of the bottle in the contour line and the vertical angle θ with respect to the horizontal of the optical axis of the camera. From the calculation. It is desirable that the direction of the camera be as horizontal as possible as described above, but in the case of a transparent wrap film, the upper edge of the opposite film through the inner surface of the bottle becomes an image depending on the height of the upper edge. In some cases, the vertical angle of the camera's directional direction is not horizontal (θ = 0) but from the bottom to the top (elevation angle) so that the upper edge of the film on the opposite side may not be displayed as an image.

When the upper edge of the wrap film is detected while the bottle is being conveyed on the conveyor as described above, the bottle is not always correctly aligned on the center line of the conveyor, and the bottle position is shifted with respect to the center line of the conveyor. The distance from the camera to the bottle varies, so even if the top edge of the wrap film is the same, if the camera's pointing direction is not horizontal, the height from the camera will be different. Become. Therefore, the amount of shift of the center line of the bottle on the conveyor is calculated from the difference in the time width of the electric signal obtained when the bottle passes through two sets of photoelectric sensors arranged so that the optical axes intersect on the conveyor. Then, the height of the contour line of the upper edge of the wrap film is corrected and calculated from the shift amount.

The inclination of the outline can be calculated from the heights of the extracted left and right ends of the outline of the wrap film.

[0015]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 8 (plan view), a bottle 3 with a transparent or translucent wrap film wound around the body is conveyed vertically on a conveyor 5. On the conveyor 5, first and second two sets of photoelectric sensors 10 and 11 for detecting the conveying speed are arranged at a predetermined interval in the conveying direction, and the light emitting units 10a and 11b are connected to the light emitting units 10a and 11b. The portions 10b and 11b are opposed to each other with the conveyor 5 interposed between each pair such that the optical axis is orthogonal to the conveyor 5.

A first and a second pair of photoelectric sensors 12 for detecting the center of the bottle 3 on the conveyor 5 are provided.
13 is a light emitting unit 12a / 13b and a light receiving unit 12
b · 13b in a diagonal relationship, that is, a point O between the two pairs of photoelectric sensors 10 and 11 on the center line of the conveyor 5 (hereinafter, this point is referred to as a reference point).
Are arranged in a crossing relationship.

The thus arranged photoelectric sensors 10.1
A first camera 14 using a two-dimensional CCD image pickup device is installed on one side of the conveyor 5 downstream of the conveyors 1, 12, and 13 in the transport direction, and a similar second camera 15 is installed on the opposite side further downstream of the conveyor 5. Have been. For each of these cameras 14, 15, two projectors 16, 17 are arranged on both sides when viewed in a plane. The light projectors 16 and 17 are oriented so that their light projection optical axes intersect with the optical axes of the cameras 14 and 15 on the center line of the conveyor 5. FIG. 9 shows this relationship in an enlarged manner. Further downstream, away from the second camera 15,
An elimination device 18 that eliminates a bottle with poor winding of the wrap film 2 is provided.

As described with reference to FIG. 4, in the case of a bottle in which the height of the upper edge 2a of the wrap film 2 is equal to or less than the height of the boundary between the body 3a and the shoulder 3b of the bottle 3. For each of the first camera 14 and the second camera 15, the cameras 14 and 15 are installed at substantially the same height as the height of the upper edge 2 a of the wrap film 2, and the projectors 16 and 17 are
Upper edge 2a of wrap film 2 on the same side as the corresponding camera
And illuminates obliquely upward toward the upper edge 2a of the wrap film 2 and emits light.

As described with reference to FIG. 6, the engraving 3 is formed on the outer surface of the bottle above the upper edge 2a of the wrap film 2.
In the case of a bottle where c exists, the first camera 14 and the second camera 14
For each of the cameras 15, the cameras are installed at a height substantially equal to the height of the upper edge 2 a of the wrap film 2, and the light emitters 16, 17 are positioned on the same side as the corresponding camera so as to be higher than the height of the upper edge 2 a of the wrap film 2. It is installed at a high position and emits light at an obliquely downward angle toward the upper edge 2a of the wrap film 2.

FIG. 10 shows a schematic configuration of the entire inspection apparatus.
Signals from the photoelectric sensors 10, 11, 12, and 13 are input to a timing controller 19, and based on the signals, the timing controller 19 generates a camera controller and an A / D converter 20 for the first camera 14 and a second A camera controller for the camera 15 and the A / D converter 21 are controlled, and an image capture signal and an image processing signal for the first camera 14 and an image capture signal and an image processing for the second camera 15 are provided. Generates a signal to generate an image processing unit 2
Output to 2. Camera controller and A / D converter 2
0.21 triggers the respective projector power supplies 23 and 24 and emits the projectors 16 and 17 for a short predetermined time (flash)
And controls the cameras 14 and 15 to store the captured images in the respective image memories 25 and 2.
6 is stored. The stored image is displayed on the image monitor 27.
・ It is projected on 28.

The image processor 22 receives image data from the image memory and the D / A converter 25 or 26 in response to the input of an image capture signal from the timing controller 19,
This is subjected to image processing by input of an image processing signal from the timing controller 19, and the result (pass / fail result of the wrap film) is notified to the timing controller 19.
When the pass / fail result from the image processing section 22 is bad, the timing controller 19 outputs a rejection signal to the rejection device 18 to reject the bottle from the conveyor 5.

FIG. 11 shows photoelectric sensors 10, 11, 12, and
13 shows the timing from the operation of No. 13 to the operation of eliminating defective bottles. In FIG. 8 and FIG. 8, TAon: time when the photoelectric sensor 10 is shielded from light by the bottle 3 TAoff: time when the photoelectric sensor 10 is shielded from light TBon: time when the photoelectric sensor 11 is shielded from light by the bottle 3 TBoff: photoelectric Assuming that the sensor 11 has become light-transmitting DA = TAoff-TAon TA = TAon + DA / 2 DB = TBoff-TBon TB = TBon + DB / 2 DAB = TB-TA When the center line of the bottle 3 passes the reference point O T
s becomes Ts = TA + DAB / 2.

TCon: Time when the photoelectric sensor 12 is shielded from light by the bottle 3 TCOff: Time when the photoelectric sensor 12 is shielded from light TDon: Time when the photoelectric sensor 13 is shielded from light by the bottle 3 TDoff: Photoelectric sensor 13 LAB: the distance between the photoelectric sensor 10 and the photoelectric sensor 11 DC = TCoff-TCon DD = TDoff-TDon Assuming that DC = TCoff-TCon, the transport speed Vcon of the conveyor 5 is Vcon = LAB / DAB. Further, the deviation amount LCD of the center line of the bottle 3 is expressed as follows: LCD = (DC−DD) / 2 × Vcon / tan (φ)

Further, LcamA: the distance from the reference point O to the first camera 14 LcamB: the distance from the reference point O to the second camera 15 Lrj: the distance from the reference point O to the exclusion device 18, DcamA1 = LcamA / Vcon DcamB1 = LcamB / Vcon. DcamA2 = DcamA3 = system-specific value DcamB2 = DcamB3 = system-specific value

FIGS. 12 to 14 show the flow of the timing control operation as described above by the timing controller 19. In steps S1 to S16 of FIG. 12, the detection of ON / OFF of the photoelectric sensors 10, 11, 12, and 13 and storage of the times are stored, and in steps S17 to S24 of FIG. In steps S25 to S30 in the drawing, an identification number is assigned to each bottle to be inspected and the image processing unit 2
2, the result of the pass / fail judgment is received. In steps S31 to S48 in FIG. 14, signals are output to the camera controller and A / D conversion units 20 and 21, the image processing unit 22, and the exclusion device 18.

FIG. 15 shows the storage of image data in the image memories 25 and 26 and the image processing section 22 for reading and storing the image data.
Shows the general flow of image processing in.

FIGS. 16 and 17 mainly show the inspection operation in the image processing in the image processing section 22. FIG. The image processing is performed by reading image data for each camera and for each bottle stored in the image memories 25 and 26.

FIG. 18 shows a bottle center line detecting operation performed as one of the bottle position detecting operations in step S63 in FIG. 16, and FIG. 19 shows a detecting method thereof. When the bottle 3 is imaged together with the background by the first camera 14 or the second camera 15, as shown in FIG. 19, the portion where the wrap film of the bottle body is wound is the brightest, and then the other portions of the bottle are the brightest. The part is bright and the background part is dark. Therefore, the minimum luminance in the image is searched, and a value α is added to the minimum luminance to obtain a slice level TH. Pixels at or above this level are searched from the left end of the image to the right and from the right end to the left. Then, it is possible to easily detect the left edge and the right edge of the bottle body that change from a dark background portion to a bright one. The X coordinate of the detected left edge is Xl, the X coordinate of the right edge is Xr,
Assuming that the width of the left and right sides of the bottle body is W, X of the center line of the bottle
The coordinates Xc are obtained by the following equation.

Xc = Xl + {W− (Xl + Xr)} / 2

Steps 91 to 99 in FIG.
FIG. 4 shows such a detection and calculation procedure, and the obtained Xc is stored in the memory in step 100.

Referring back to FIG. 16, the upper edge 2a of the wrap film 2 is clarified by performing a known edge enhancement process on the image data in step S66, and then the contour of the upper edge 2a is determined in the next step S67. Is extracted. In the next step S68, after the extracted outlines are recognized by labeling, if there are a plurality of outlines that are recognized labels, mutual recognition is performed based on the x- and y-direction coordinates of both ends of each outline. Are examined, and if the distance is equal to or less than a certain value, the two are combined as the same contour line (interpolation of the divided portion). FIG. 20 shows the processing procedure. Here, the bonding process is performed in the case of a transparent film where the brightness is low and the outline may be cut off and separated, and even in the case of a translucent film, the light reflected or refracted from the glass surface of the bottle may be used. This is because they may be divided by such factors.

Since some of the contours processed in this way are other than those formed by the upper edge 2a of the wrap film 2, only the optimal contour is specified in the next step S69. The identification is performed by extracting the following four feature values and determining the magnitude of the value. (1) Luminance Since the luminance of the upper edge differs depending on the type of the wrap film, the luminance is checked, and labels (contour lines) having extremely different luminances are excluded. (2) Length Since the length of the upper edge of the wrap film is determined by the diameter of the bottle, extremely long or short ones are excluded. (3) Pixel Density When there are many divisions (interpolation) at the time of contour line extraction, it often does not depend on the upper edge of the wrap film.
If the interpolation ratio to the length is large (the pixel density is small), it is excluded. (4) Position (Height) When there are a plurality of labels (contour lines) satisfying the above three conditions, the one with the highest height or the one with the lowest height is selected. FIG. 21 shows the procedure of such a specific process.

After detecting the position (height) of the identified label, that is, the upper edge of the wrap film, on the image in step S71 in FIG. 16, errors are corrected in step S72 due to the inclination of the camera. In this apparatus, in order to obtain the installation information of the cameras 14 and 15 in advance, the following calibration is performed in advance for each camera 14 and 15 using a standard sample bottle on which the wrap film 2 is correctly wound as a standard gauge.

In FIG. 22, the upper edge of the standard wrap film shown on the left side of FIG. 22 is subjected to the same edge emphasis, contour extraction, labeling and label combining, and label specifying processing as described above. It is assumed that each of the 14 and the second camera 15 has been detected as a contour line (gauge) as shown on the right side of FIG. Here, d11: the height of the left end based on the center of the gauge on the first camera 14 side d1r: the height of the right end based on the center of the gauge on the first camera 14 side d21: the gauge on the second camera 15 side D2r: height of the right end with reference to the center of the gauge on the second camera 15 side W1: width in the horizontal direction of the gauge on the first camera 14 side W2: side of the second camera 15 H1: Vertical width of inspection range on first camera 14 side H2: Vertical width of inspection range on second camera 15 side H1c: Gauge center in inspection range on first camera 14 side H2c: Height of the center of the gauge in the inspection range on the second camera 15 side D: Diameter of the gauge r: Radius of the gauge H: Height of the gauge Assuming that: (Mm / pixel), vertical angle (depression angle or elevation angle) Rotation angle (horizontal inclination) to calculate the height from the conveyor 5 to the center of the test range.

Resolution of first camera 14 = D / W1 Resolution of second camera 15 = D / W2 Vertical angle of first camera 14 = tan ^-1 (d11 + d1r) / 2
/ (R−cos θ × r) Vertical angle of the second camera 15 = tan ⁻¹ (d2l + d2r) / 2
/ (R−cos θ × r) rotation angle of first camera 14 = tan ⁻¹ (d11−d1r) / 2
/ (R-cos θ × r) Vertical angle of the second camera 15 = tan ⁻¹ (d21−d2r) / 2
/ (R−cos θ × r) Height of the first camera 14 = H + H1 + / 2−H1c Height of the second camera 15 = H + H2 + / 2−H2c FIG. 23 shows the procedure of such a calibration process.

FIG. 24 shows a step S72 in FIG.
A detailed procedure of the correction processing performed in step (1) will be described. The correction is
There are a case depending on the vertical angle of the camera and a case depending on the rotation angle. Explaining from the former correction, step S1 in FIG.
At 51, the height data of the upper edge of the wrap film is sequentially read from the image memory by one pixel from the center to the left and right, and at step S152, the resolution of the camera detected as described above and the number of pixels from the center are obtained. , The distance L from the center of the pixel is calculated. And
In the next step S153, a correction value Fa is calculated from the distance L, the vertical angle θ of the camera detected as described above, and the diameter D at the upper edge portion of the wrap film, as shown in FIG. The correction value Fa is obtained by the following equation.

Fa = D / 2 × (1-√ [1- (2L /
D) ² ]) × sin (θ) Here, it is shown that the portion from the bracket symbol “[” to the bracket symbol “]” is enclosed by a square root √.

Assuming that the height before correction is H0, the height H1 after correction is H1 = H0 + Fa, and the storage is rewritten to the sum of the values. Such a correction is performed for all pixel data forming the upper edge of the wrap film.

The correction based on the rotation angle of the camera is shown in FIG.
The processing is performed in steps S156 to S160 of step S4. In this case, assuming that the distance from the center of the pixel to the center is L and the rotation angle of the camera is α, the correction value Fb is obtained by the following equation as shown in FIG.

Fb = L × tan (α)

Assuming that the height before correction is H1, the height H2 after correction is H2 = H1 + Fb, and the storage is rewritten to the value obtained by adding H2 = H1 + Fb. Such correction is also performed for all pixel data forming the upper edge of the wrap film.

Next, in step S73 of FIG.
Correction is made based on misalignment of the bottle center line. FIG. 27 shows the processing procedure. The position (X coordinate) of the bottle center line is shown in FIG.
8 and FIG. 19, and before that, the displacement of the bottle 3 on the conveyor 5 is detected by the timing controller 19 based on signals from the two sets of photoelectric sensors 12 and 13 as described above. Since they have been stored in advance, the deviation amount of the bottle center line can be easily obtained from these data. Therefore, step S in FIG.
In step 161, a correction value Fc is obtained from the displacement Ld and the vertical angle θ of the camera by the following equation.

Fc = Ld × tan (θ)

In the next step S162, the height data of the upper edge of the wrap film is read from the image memory one pixel at a time from the left end to the right end.
At 63, the storage is rewritten by adding the correction value Fc.

After performing the above-described correction, the position data of the upper edge of the wrap film is converted into the height from the lower end of the bottle in step S74 in FIG. 16, and stored for each camera and for each bottle identification number. (Step S89,
S90), the processing shown in FIG. 17 is performed as the next inspection.

In the inspection, the magnitude of the inclination of the upper edge of the wrap film is calculated, and after calculating the maximum value and the minimum value of the upper edge of the wrap film, it is determined whether or not the calculated value exceeds the limit value. It is determined whether or not there is any. In this apparatus, since two cameras 14 and 15 are used, it is possible to calculate from an image of one camera or from images of two cameras. The calculation method differs between the two cases.

FIG. 28 shows a calculation method when one camera is used. Here, d1: the height of the left edge of the upper edge of the wrap film with reference to the center of the inspection range d2: the height of the right edge of the upper edge of the wrap film with reference to the center of the inspection range Hmin: the height of the upper edge of the wrap film Hmax: Maximum value of the height of the upper edge of the wrap film L1: Distance from the center of the inspection range to the left end L2: Distance from the center of the inspection range to the right end D: Diameter of the upper end portion of the wrap film to be inspected θ: Assuming that sin ^-1 (L1 / D) or sin ^-1 (L2 / D), the magnitude S of the inclination of the upper edge of the wrap film is given by the following equation.

S = √ [(d1 × D / L1) ² + (d2 × D /
L2 / cos (90-θ)) ² ] Here, it is shown that the portion from the bracket symbol “[” to the bracket symbol “]” is enclosed by a square root √.

The magnitude S of the inclination thus obtained is compared with a limit value, and if it exceeds the limit value, a rejection signal is sent to the rejection device 18 as a defective bottle. In addition, when the minimum value Hmin of the height of the upper edge of the wrap film is less than the limit value and when the maximum value Hmax of the height of the upper edge of the wrap film exceeds the limit value, it is determined that the bottle is defective (step S86 in FIG. 17).
To S90).

FIG. 29 shows a calculation method when two cameras are used. Here, H11: the height of the left edge of the upper edge of the wrap film on the first camera 14 side H1r: the height of the right edge of the upper edge of the wrap film on the first camera 14 side H21: the height of the upper edge of the wrap film on the second camera 15 side Assuming that the height at the left end is H2r: the height at the right end of the upper edge of the wrap film on the second camera 15 side, the magnitude S of the inclination of the upper edge of the wrap film is given by the following equation.

S = {[(H1r−H2l) ² + (H11−H2r) ² ] Here, it is shown that the square brackets “[” to “]” are enclosed by a square root}.

Also, the maximum value Hmax of the upper edge of the wrap film
And the minimum value Hmin is the height H11, H21, H1r, H2r.
And the magnitude S of the inclination are obtained by the following equation.

Hmax = (H11 + H21 + H1r + H2r) / 4 + S / 2 Hmin = (H11 + H21 + H1r + H2r) / 4-S / 2

Then, as in the case of a single camera, the magnitude S of the inclination is compared with the limit value, and if it exceeds the limit value, a rejection signal is sent to the rejection device 18 as a defective bottle. Further, when the minimum value Hmin of the height of the upper edge of the wrap film is less than the limit value, and when the maximum value H of the height of the upper edge of the wrap film is higher.
When max exceeds the limit value, it is regarded as a defective bottle.

[0056]

As described above, according to the present invention, the outline of the upper edge of the transparent or translucent wrap film appears so as to be clearly distinguished from other images on the image of the camera, and furthermore, the bottle cylinder is formed. Since the upper edge of the wrap film is detected without being affected by the curvature of the outer surface as much as possible, it is possible to accurately detect the upper edge and accurately calculate the height, inclination, and the like.

[Brief description of the drawings]

FIG. 1 is an optical relationship diagram showing that, when an upper edge of a wrap film wound around a bottle body is illuminated by a projector and imaged by a camera, reflected light scattered by the wrap film enters the camera. is there.

FIG. 2 is an optical relationship diagram showing that reflected light from the inner surface of the bottle enters the camera.

FIG. 3 is an optical relationship diagram showing that reflected light from the outer surface of the bottle enters the camera.

FIG. 4 is an optical relationship diagram showing the first embodiment of the present invention.

FIG. 5 is an optical relationship diagram when the arrangement relationship between the projector and the camera is reversed from that in FIG. 4;

FIG. 6 is an optical relationship diagram showing a second embodiment of the present invention.

FIG. 7 is an optical relationship diagram when the arrangement relationship between the projector and the camera is reversed from that in FIG. 6;

FIG. 8 is a diagram showing a planar arrangement relationship of an inspection apparatus that performs the method of the present invention.

FIG. 9 is an enlarged view of a planar positional relationship between one camera, two projectors, and a bottle in FIG. 8;

FIG. 10 is a block diagram showing an electrical configuration of the inspection device.

FIG. 11 is a timing chart of the operation of the inspection apparatus.

FIG. 12 is a flowchart of a timing control operation by the timing controller in FIG. 10;

FIG. 13 is a flowchart following FIG. 12;

FIG. 14 is a flowchart following FIG. 13;

FIG. 15 is a flowchart showing an outline of processing by an image processing unit in FIG. 10;

FIG. 16 is a flowchart mainly showing an inspection process in an image processing unit.

FIG. 17 is a flowchart following FIG. 16;

FIG. 18 is a flowchart of a process for detecting the position of the center line of the bottle.

FIG. 19 is an explanatory diagram illustrating a method of detecting the position of the bottle center line.

FIG. 20 is a flowchart of a process of combining the divided outlines at the upper edge of the wrap film.

FIG. 21 is a flowchart of a process for specifying an upper edge of a wrap film.

FIG. 22 is an explanatory diagram of calibration performed in advance for each of two cameras using a standard sample bottle on which a wrap film is correctly wound as a standard gauge.

FIG. 23 is a flowchart of a calibration process.

FIG. 24 is a flowchart of a process for performing error correction based on camera tilt.

FIG. 25 is an explanatory diagram for explaining correction based on the vertical angle of the camera.

FIG. 26 is an explanatory diagram for explaining correction based on the rotation angle of the camera in the left-right direction.

FIG. 27 is a flowchart of a process for performing error correction due to a deviation of a bottle center line.

FIG. 28 is an explanatory diagram illustrating a method of calculating the magnitude of the inclination of the upper edge of the wrap film from an image from one camera.

FIG. 29 is an explanatory diagram illustrating a method of calculating the magnitude of the inclination of the upper edge of the wrap film from images from two cameras.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Floodlight 2 Wrap film 2a Upper edge of wrap film 3 Bottle 3a Bottle trunk 3b Bottle shoulder 3c Bottle sculpture part 4 Camera 5 Conveyor 10.11.12.13 Photoelectric sensor 14.15 Camera 16.17 Floodlight 19 Timing controller 22 Image processing unit

Claims (6)

(57) [Claims] 1. A method for detecting the upper edge of a transparent or translucent wrap film wound around the outer periphery of a bottle by a camera and detecting the upper edge by electrical image processing, comprising: However, for a bottle whose height is equal to or less than the height of the boundary between the body and the shoulder of the bottle, place the camera at approximately the same height as the top edge of the wrap film, and place the projector on the same side of the wrap film as the camera. It is installed at a position lower than the upper edge height, emits light obliquely upward toward the upper edge of the wrap film, and images the upper edge of the illuminated wrap film with reflected light using a camera. Method for detecting the upper edge of a transparent or translucent wrap film. 2. A method in which an upper edge of a transparent or translucent wrap film wound around the outer periphery of a body of a bottle is imaged by a camera and detected by electrical image processing. For a bottle with a sculpture on the outside of the bottle, set the camera at almost the same height as the top edge of the wrap film, and set the projector on the same side as the camera and higher than the top edge of the wrap film. A transparent or translucent wrap film, characterized by projecting light obliquely downward toward the upper edge of the wrap film and projecting the upper edge of the illuminated wrap film with a camera using reflected light. Edge detection method. 3. The method for detecting the upper edge of a transparent or translucent wrap film according to claim 1, wherein two projectors are arranged on both sides of one camera as viewed in a plane. . 4. After extracting the contour of the upper edge of the wrap film from the image of the camera, the height of the contour is determined by the diameter D of the bottle in the contour and the vertical direction with respect to the horizontal of the optical axis of the camera. 4. The method for detecting the upper edge of a transparent or translucent wrap film according to claim 1, wherein a correction operation is performed from the angle θ. 5. The method according to claim 1, wherein the bottles are conveyed on a conveyor, and a difference in a time width of an electric signal obtained when the bottles pass through two sets of photoelectric sensors arranged so that optical axes intersect on the conveyor is represented by the following formula:
The transparent or translucent transparent according to claim 4, wherein a shift amount of a center line of the bottle on the conveyor is calculated, and a height of a contour line of an upper edge of the wrap film is corrected and calculated from the shift amount. Upper edge detection method for wrap film. 6. The upper edge detection of a transparent or translucent wrap film according to claim 4, wherein the inclination of the outline is calculated from the heights of the extracted right and left edges of the upper edge of the wrap film. Method.