JP6197542B2 - Appearance inspection apparatus, appearance inspection method, and program - Google Patents

Description

  The present invention relates to an appearance inspection apparatus, an appearance inspection method, and a program for causing a computer to execute the method for inspecting a welding state of a sheet-like material.

  Regarding the welding of sheet-like materials, the end of one or two resin thin films is welded to form a container mainly for the purpose of packaging retort foods and medicines. An example of a method for inspecting whether or not the welded portion is normal is disclosed in Patent Documents 1 and 2. Patent Document 1 proposes a method of accurately detecting an altered or deformed edge by welding a transparent tube along the outer periphery. Patent Document 2 proposes a method in which an inspection position is set with reference to a detected edge, and the quality of a welded state is determined by observing transmitted light or reflected light of a welded portion.

  Patent Document 3 discloses a method that enables the quality of a welded state to be judged visually by using a sheet whose transmittance changes by heating. The method disclosed in Patent Document 3 uses a porous sheet that is usually opaque but has a property of becoming transparent when heated. According to this property, Patent Document 3 proposes to clarify welding conditions that hardly cause defects such as sheet tearing and leakage from a welded part after the sheet is wrapped in a bag shape.

  Here, the quality determination method of the welding state using the property of the sheet | seat disclosed by patent document 3 is demonstrated with reference to figures. Here, a case where two sheets are overlapped and partially heated will be described.

  FIG. 8A is a plan view showing the sheet surface when the welded state is normal, and FIG. 8B is a plan view showing the sheet surface when the welded state is defective.

  As shown in FIG. 8A, when a part of the sheet 6 is heated and the melted part 80 becomes transparent, the light passes through the melted part 80 and is reflected by the background 7. The color becomes visible. Thereby, it turns out that the welding state of the fusion | melting part 80 is favorable. On the other hand, in the case shown in FIG. 8B, the melted part 81 is opaque and the light 7 is insufficiently transmitted, so that the background 7 cannot be seen in the melted part 81. As a result, it can be seen that the welded state of the melted portion 81 is poor.

  In this way, the quality of the welded state can be easily determined by using the properties of the sheets, irradiating the welded portions of the two sheets with light, and observing the welded portions.

  Further, Patent Document 4 discloses a method for inspecting an adhesion state in a process of overlapping and adhering both ends of a cylindrical film. In the method disclosed in Patent Document 4, the brightness of each of the four parts of the film, the film adhesion part, the film overlap, but the non-adhesion part, and the outer ear part is detected, and the detected brightness is detected. Based on the above, the adhesion failure is determined.

Japanese Patent No. 2877291 Japanese Patent No. 2915785 JP-A-10-55795 Japanese Patent No. 5138430

  In the method disclosed in Patent Document 2, an image obtained by photographing a heat seal is inspected in a line shape, the number of pixels below a certain luminous intensity level is counted, and the counted number of pixels is different from a preset number of pixels. There is a problem that it takes time when the inspection area is wide. This will be specifically described below.

  When the method disclosed in Patent Literature 2 is applied to general inspection of a welded portion, it is necessary to increase the resolution of imaging to about several tenths of the size of the weld mark. Therefore, if the weld mark is about 2 mm, the resolution is several tens of μm and the field of view is several tens of mm. Therefore, the contents may be 100 mm square or more, and the time required for photographing is enormous. It will be a thing. As a result, it is difficult to apply the method disclosed in Patent Document 2 in-line, and the method is limited to the purpose of prior evaluation of the welding process and lot fluctuation confirmation.

  The method disclosed in Patent Document 4 relates to the determination of the quality of adhesion, and the problem of adhesion is not directly applicable to the inspection of the welded state, unlike the problem that can occur in welding. For example, in the case of welding, if a gap occurs between the upper side and the lower side of two sheets due to floating, it becomes defective, but in the case of bonding, if there is an adhesive between the two sheets, the gap between the sheets This distance does not matter and is determined to be normal.

  The present invention has been made to solve the above-described problems of the technology, and has a visual inspection apparatus, a visual inspection method, and a method for executing the method on a computer, which make it possible to more easily determine the quality of a welded state. The purpose of this is to provide a program.

In order to achieve the above object, the visual inspection apparatus of the present invention has a plate-like object sandwiched between two sheets having the property of partially transmitting the light irradiated on the surface, and the periphery is welded to pack the bag. It is an appearance inspection device that determines the quality of welding in the process of performing,
Imaging means for imaging in a state of irradiating the welded inspection object with uniform diffused light and converting it into image data;
The first reference luminance, which is the luminance of the sheet surface in an image taken by irradiating the diffused light on the surface of one sheet, and the diffused light in a state where the two sheets are stacked and normally welded Holding means for preliminarily holding a second reference luminance that is the luminance of the sheet surface in an image taken by irradiating
The determination target luminance, which is the luminance of the inspection region in the image captured by the imaging unit, of the inspection target irradiated with the diffused light is compared with the first and second reference luminances, and the determination target luminance and the second When the difference between the reference luminance and the first reference luminance is within a predetermined range, the welding state of the inspection region is determined to be normal, and the difference between the reference luminance and the first reference luminance is within the predetermined range, Determining means for determining that the welded state of the inspection region is defective;
It is the structure which has.

Further, the appearance inspection method of the present invention is a method of welding in the step of sandwiching a plate-like object between two sheets having a property of partially transmitting the light irradiated on the surface, and welding the periphery to pack the bag. An appearance inspection method for determining pass / fail,
The first reference luminance, which is the luminance of the sheet surface in an image photographed by irradiating uniform diffused light on the surface of one sheet, and the diffusion in a state where the two sheets are stacked and normally welded Preparing a second reference luminance which is the luminance of the sheet surface in an image taken by irradiating light,
What is photographed in a state of irradiating the diffused light to the inspection object on which the sheet is stacked and welded, is converted into image data,
The determination target luminance that is the luminance of the inspection region in the image obtained by photographing the inspection target irradiated with the diffused light is compared with the first and second reference luminances, and the determination target luminance and the second reference luminance are If the difference is within a predetermined range, the welding state of the inspection area is determined to be normal, and if the difference between the determination target luminance and the first reference luminance is within the predetermined range, The welding state is determined to be defective.

Furthermore, the program of the present invention determines whether or not the welding is good in the step of sandwiching a plate-like object between two sheets having the property of partially transmitting the light irradiated on the surface, and welding the periphery to form a bag. A program for causing a computer to execute determination processing, wherein the computer
The first reference luminance, which is the luminance of the sheet surface in an image photographed by irradiating uniform diffused light on the surface of one sheet, and the diffusion in a state where the two sheets are stacked and normally welded A procedure for storing a second reference luminance that is a luminance of a sheet surface in an image taken by irradiating light;
A procedure for converting what is photographed in a state of irradiating the diffused light to the inspection object on which the sheets are stacked and welded, and
The determination target luminance that is the luminance of the inspection region in the image obtained by photographing the inspection target irradiated with the diffused light is compared with the first and second reference luminances, and the determination target luminance and the second reference luminance are If the difference is within a predetermined range, the welding state of the inspection area is determined to be normal, and if the difference between the determination target luminance and the first reference luminance is within the predetermined range, The procedure for determining that the welding state is defective is executed.

  According to the present invention, the quality of the welded state can be determined more easily.

It is a figure for demonstrating the principle of the external appearance inspection method of this embodiment. It is a cross-sectional schematic diagram for demonstrating the principle of the external appearance inspection method of this embodiment. It is a block diagram which shows the example of 1 structure of the external appearance inspection apparatus of this embodiment. It is a flowchart which shows the procedure of the external appearance inspection method of this embodiment. It is a figure for demonstrating the specific example of the external appearance inspection method of this embodiment. It is a figure for demonstrating the specific example of the external appearance inspection method of this embodiment. It is a block diagram which shows the example of 1 structure of the external appearance inspection apparatus of one Embodiment of this invention. It is a figure which shows an example of the related method about the quality determination of a welding state.

  The principle of the appearance inspection method of this embodiment will be described. In the present embodiment, the sheet means a sheet-like material such as a resin film.

  In the present embodiment, the sheet to be inspected is a porous thin film, and has a property of partially transmitting the light irradiated on the sheet surface. Due to its nature, the surface brightness when photographing a sheet under diffused light typified by a ceiling light is such that only one sheet is present, two sheets are overlapped, and three or more sheets are present. Different in overlapping state.

  Here, a case where there is only one sheet and a case where there are two sheets will be described. FIG. 1A shows a case where there is only one sheet, and FIGS. 1B and 1C show a case where there are two sheets.

  As shown in FIG. 1B, when two sheets are in contact with each other, that is, when the upper sheet 6a and the lower sheet 6b are in close contact with each other, the light transmitted through the upper sheet 6a is reduced. The part is reflected by the lower sheet 6b and passes through the upper sheet 6a and returns. Therefore, the sheet surface 61 of the upper sheet 6a shown in FIG. 1B looks whitish compared to the sheet surface 60 in the case of “only one sheet” shown in FIG.

  On the other hand, as shown in FIG. 1C, in the state where there is a certain gap between the upper sheet 6a and the lower sheet 6b, the brightness of the sheet surface 62 is as shown in FIG. It becomes equivalent to the brightness of the sheet surface 60. As a case where a gap is formed between the two sheets, for example, a case where the upper sheet 6a is lifted in the welding process is considered.

  The case of FIG. 1B and FIG. 1C will be described in the case where a plate-like object is sandwiched between two sheets. FIG. 2 is a schematic cross-sectional view for explaining the principle of the appearance inspection method of the present embodiment.

  The sheet surface after forming the bag with the plate-like material 9 sandwiched between the two sheets 6 is photographed, and the luminance distribution of the welded portion is measured. When the welded state is normal as shown in FIG. 2A, the luminance of the melted portion 80 becomes equal to the luminance of the sheet surface 61 due to the properties described with reference to FIG. On the other hand, when the welded state is poor as shown in FIG. 2B, the brightness of the melted portion 81 is equivalent to the brightness of the sheet surface 60 when there is only one sheet due to a gap formed between the sheets. .

  The appearance inspection method according to the present embodiment determines the quality of the welded state by using the property that the brightness of the light reflected on the sheet varies depending on the presence or absence of a gap between the sheets after welding.

  Based on the above-described principle, the configuration of an appearance inspection apparatus that determines the quality of the welded state will be described.

  The appearance inspection apparatus according to the present embodiment is provided in an area of a production line, for example, in a process in which one sheet is folded or two sheets are stacked and end surfaces of sheet-like materials are welded to form a bag. The quality of the welded state is determined according to the surface brightness of the welded portion.

  In the present embodiment, it is assumed that a bag-like object in which a plate-like object is sandwiched between two sheets and a plurality of inner portions are welded along the outer periphery of the two sheets to form a bag-like object is to be inspected. .

  FIG. 3 is a block diagram illustrating a configuration example of the appearance inspection apparatus according to the present embodiment.

  As shown in FIG. 3, the appearance inspection apparatus includes a camera 1 that photographs a bag-like object 5 to be inspected, an illumination 2 that irradiates visible light onto an inspection region of the bag-like object 5, and a bag-like object 5 to be inspected. Is provided under illumination and has a stage 3 for positioning, and an information processing device 4 for determining the quality of the welded portion. As the information processing apparatus 4, a general-purpose computer such as a personal computer can be used.

  When the information processing apparatus 4 receives the display unit 46 that outputs the result of the appearance inspection and the image data captured by the camera 1 is input, the image processing unit 4 performs the appearance inspection by predetermined image processing and displays the result. The inspection control unit 14 outputs to 46.

  The camera 1 is a photographing device capable of photographing at a viewing angle of about 200 to 300 mm at a photographing distance of about 100 mm to 300 mm. The camera 1 has a lens (not shown) and an image sensor (not shown). The camera 1 has an ability to take at least one image within a welding time for each bag-like object and transfer a video signal of the taken image to the inspection control unit 14.

  The illumination 2 is an illumination device that can uniformly irradiate the entire surface of the bag 5 to be inspected and has high diffusibility. The illumination 2 is, for example, diffuse illumination or indirect illumination represented by a fluorescent lamp or LED (Light Emitting Diode).

  Next, the configuration of the information processing apparatus 4 will be described in detail.

  The display unit 46 is an output device such as a display device and a printer, and outputs a result of an appearance inspection input from the inspection control unit 14.

  The inspection control unit 14 includes an image input unit 41, an illumination control unit 42, a memory 43, an image processing unit 44, a stage control unit 45, a result processing unit 47, and a CPU (Central Processing Unit) 40 that controls each unit. And have.

  Each time the CPU 40 receives information from the stage controller 45 that the position of the stage 3 has been set in order to photograph the bag-like object 5, the CPU 40 controls the light amount of the illumination 2 by the illumination controller 42 and causes the camera 1 to photograph. Instruct the operation.

  When the bag-like object 5 to be inspected is carried in, the stage control unit 45 supplies the bag-like object 5 to the stage 3 and controls the stage 3 to determine the positional relationship between the end face of the bag-like object 5 and the camera 1. When adjustment is made and the position of the stage 3 is set, the CPU 40 is notified of this.

  The image input unit 41 controls the camera 1 in accordance with an instruction from the CPU 40, converts a video signal input from the camera 1 into image data, and stores the image data in the memory 43. Hereinafter, image data obtained by photographing the bag-like object 5 to be inspected is referred to as inspection image data. The illumination control unit 42 controls the amount of light of the illumination 2 in accordance with an instruction from the CPU 40.

  The memory 43 is, for example, a nonvolatile memory. The memory 43 holds in advance a first reference luminance that is the luminance of the sheet surface and a first allowable range that is an allowable range in an image captured by irradiating the surface of one sheet with the irradiation light of the illumination 2. ing. The memory 43 is a second reference luminance that is the luminance of the sheet surface in an image taken by irradiating the irradiation light of the illumination 2 in a state in which the two sheets are stacked and normally welded, and an allowable range thereof. The second allowable range is held in advance. The memory 43 holds inspection image data sequentially input from the image input unit 41.

  The image processing unit 44 sequentially reads the inspection image data from the memory 43 and executes a predetermined inspection program on each inspection image data. As a result, the image processing unit 44 identifies all the predetermined inspection areas for the inspection image data, stores the recognition results including the luminance values of the inspection areas in the memory 43, and allows the user to visually recognize the recognition results. It is displayed on the display unit 46 in a form that can be performed. Hereinafter, the luminance of the inspection area is referred to as “determination target luminance”.

  The result processing unit 47 reads the determination target luminance information from the memory 43 and compares the determination target luminance with the first and second reference luminances to determine whether the welded state is good or not as follows. When the difference between the determination target luminance and the second reference luminance is within a predetermined range, the result processing unit 47 determines that there is no gap in the welded portion in the inspection region and the welding state is normal. In addition, when the difference between the determination target luminance and the first reference luminance is within a predetermined range, the result processing unit 47 determines that the welded portion in the inspection region has a gap and the welding state is poor. Then, the result processing unit 47 outputs the inspection result including the determination result of the welded state to the display unit 46. In addition, the result processing unit 47 determines whether or not the welded state is good with respect to all the inspection regions determined in advance for each bag-like object 5.

  An example of the welding state pass / fail determination method will be specifically described. The result processing unit 47 compares the determination target luminance with the second reference luminance, and determines that the welding state is normal when the difference between these luminances is within the second allowable range. In addition, the result processing unit 47 has a difference between the determination target luminance and the second reference luminance larger than the second allowable range, and a difference between the determination target luminance and the first reference luminance is within the first allowable range. If there is, the welding state is determined to be defective.

  When an external device (not shown) is connected to the information processing apparatus 4, the result processing unit 47 may transmit the inspection result to the external device and cause the output unit of the external device to output the inspection result.

  In the present embodiment, the case where each of the image input unit 41, the illumination control unit 42, the image processing unit 44, the stage control unit 45, and the result processing unit 47 is configured by a dedicated circuit has been described. The functions of the image input unit 41, the illumination control unit 42, the image processing unit 44, the stage control unit 45, and the result processing unit 47 are executed by the CPU 40 executing processes according to a program stored in the memory 43 in advance. It may be.

  Next, an operation procedure of the appearance inspection method by the appearance inspection apparatus of the present embodiment will be described. FIG. 4 is a flowchart showing the procedure of the appearance inspection method of the present embodiment.

  When the bag-like object 5 to be inspected is supplied to the stage 3 (step S1), the inspection control unit 14 controls the stage 3 to adjust the positional relationship between the end face of the bag-like object 5 and the camera 1, and the camera 1 Then, the illumination 2 is controlled to cause the camera 1 to photograph the appearance of the bag-like object 5 (step S2). The video signal output from the camera 1 is converted into image data via the image input unit 41 and stored in the memory 43 (step S3).

  The inspection control unit 14 measures the edge position or the corner position indicating the outline of the bag-like object 5 from the inspection image data on the memory 43 acquired in step S3 (step S4), and based on the result, the welding state An inspection area on the image to be inspected is set (step S5). Note that the number of inspection regions may be either singular or plural, and the procedure up to the setting is not limited as long as the inspection region setting method has a high correlation with the quality of the welded state.

  The inspection control unit 14 acquires information on the luminance to be determined in the set inspection region from the image data (step S6). Subsequently, the inspection control unit 14 compares the determination target brightness acquired in step S6 with the reference brightness (second reference brightness) in the normal welding state and the reference brightness (first reference brightness) of the sheet alone. Thus, the quality of the welded state of the inspection area is determined (step S7).

  Specifically, when the difference between the determination target luminance and the second reference luminance is within the second allowable range, the inspection control unit 14 determines that the determination target luminance is equivalent to the luminance in the normal welding state, It is determined that the welding state is normal. On the other hand, the inspection control unit 14 determines that the difference between the determination target luminance and the second reference luminance is larger than the second allowable range, and the difference between the determination target luminance and the first reference luminance is the first allowable range. If it is within the range, it is determined that the determination target luminance is equivalent to the surface luminance of the single sheet, and the welding state is determined to be defective. In this case, it is considered that the bag-like object 5 is not normally welded and the upper sheet of the two is lifted.

  Thereafter, the inspection control unit 14 stores the inspection result in step S7 in the memory 43 and transfers it to the display unit 46 (step S8).

  Subsequently, the inspection control unit 14 determines whether or not determination processing for all inspection regions set for the bag-like object 5 on the stage has been completed (step S9). As a result of the determination in step S9, when the determination process has not been completed for all of the set inspection areas, the inspection control unit 14 executes the determination processes in steps S6 to S8 for the next inspection area. On the other hand, as a result of the determination in step S9, when the determination process has been completed for all of the set inspection areas, the inspection control unit 14 discharges the bag-like object 5 on the stage, and returns to the operation in step S1. Then, the processes in steps S2 to S10 are performed on the bag 5 to be inspected next supplied to the stage 3.

  Note that the supply of the inspection target is not limited to the case of supplying only the bag-like material 5, and the plate-like material 9 may be supplied to the stage 3 as a content between the sheets.

  Next, a detailed example of the inspection region setting and luminance information acquisition operation will be described with reference to FIGS.

  FIG. 5 is a diagram showing an example when the sheet is welded normally, and FIG. 6 is a diagram showing an example when the sheet is welded poorly. Each of FIG. 5 and FIG. 6 includes a plan view when the bag-like object 5 is viewed from above, a side view when the bag-like object 5 is viewed from the right side of the figure (right side of the figure), and a melting part. Sectional drawing (lower side of figure) of the position of the line which passes along 80 is shown.

  Note that the bag-like object 5 to be inspected is placed on a sheet 6 with a plate-like object 9, and another sheet 6 is stacked on the plate-like object 9 so as to cover the plate-like object 9. Of the four sides of the sheet, two or three sides that do not intersect are welded.

  In the normal welding state, as shown in FIG. 5, the bag-like object 5 has a higher brightness of the surface portion 61 of the stacked sheet 6 than the brightness of the surface portion 60 of the sheet 6 alone ( = White).

  On the other hand, as shown in FIG. 6, when there is an insufficient melting portion 81 near the lower right corner of the bag-like object 5, the thickness of the plate-like object 9 sandwiched between the two sheets 6, The space between the sheets is empty. In this state, the melting portion 81 has a luminance equivalent to that of the surface portion 60 of the sheet 6 alone.

  Here, an example of a method for obtaining the corner position of the bag-like object 5 in consideration of the case where the sheet 6 is lifted as described with reference to FIG. 6 will be described. The image processing unit 44 detects the edges of the four sides of the bag-like object 5 at a plurality of points, and then linearly approximates each point group obtained as an outline, and determines the intersection of the approximate straight lines of adjacent sides as a corner. To do.

  Next, a modified example related to the setting of the determination target luminance used for the quality determination of the welded portion will be described with reference to FIGS. 5 and 6. Hereinafter, the case where the image processing unit 44 specifies the contour or corner of the sheet 6 as described above will be described.

(Modification 1)
In this modification, the average luminance in a preset area is set as the determination target luminance.
In this modification, the memory 43 has a standard brightness which is a standard brightness of the surface of the sheet when the sheets 6 are overlapped, and a distance from the corner of the sheet to the designed melting part 80 separately from the welded part. The distance information that is the information of the above is held in advance.

  The image processing unit 44 calculates the welding position in the image of the inspection image data from the design distance information to the melting unit 80 with the specified corner as a reference, and uses the calculated welding position as a reference for the two sheets 6. One or more rectangles are specified in a range avoiding the position of the plate-like object 9 sandwiched therebetween. The image processing unit 44 pays attention to the rectangle 53 closest to the entrance of the bag-like object 5 among the specified rectangles, and obtains the average luminance inside the rectangle 53. If the difference between the average luminance and the standard luminance is within a predetermined range, the result processing unit 47 determines that the welding state is normal, and the difference between the average luminance and the luminance of the surface portion 60 of the sheet 6 alone is predetermined. If it is within the range, the welding state is determined to be defective. The setting conditions, size, number, and the like of the rectangle 53 are not limited to those shown in FIGS. 5 and 6 and are not limited.

(Modification 2)
In this modification, the mode value having the maximum luminance distribution frequency in a preset area is set as the determination target luminance.

  When the brightness of the welding mark contained in the rectangle 53 is very small compared to the surface brightness of the bag-like object 5 due to the circumstances of the photographing environment, and it is difficult to compare with the average brightness in the first modification, image processing is performed. The unit 44 obtains a histogram of the luminance inside the rectangle 53, and provides the result processing unit 47 with the luminance of the peak (frequency maximum value) excluding the luminance of the welding mark as the determination target luminance.

  In this modification, the determination is made using the representative luminance inside the rectangle 53, so that the determination accuracy can be expected to be higher than the method using the average value. Also in this modification, the setting conditions, size, number, etc. of the rectangle 53 are not limited.

(Modification 3)
This modification prevents erroneous determination of the quality of the welded state when the brightness in the region around the welded trace is uneven even when the welded state is normal.

  In the case where it is difficult to determine the welding state only with the luminance value of a predetermined location, such as when the luminance around the welding mark is uneven, the image processing unit 44 displays the specified sheet contour or corner. Based on the coordinates of the design center position of the fusion zone 80, a linear or belt-like region 54 separated by a predetermined distance is defined. 5 and 6 show the case of the belt-like region 54, but here, a case where a line is set will be described.

  Then, the image processing unit 44 acquires luminance value variation characteristics with respect to the set line scanning direction. In the case illustrated in FIG. 5, the image processing unit 44 reads the variation characteristic of the luminance value from the inspection image data in the horizontal coordinate range of the drawing. Subsequently, the result processing unit 47 calculates the difference between the read fluctuation characteristics and the fluctuation characteristics of the normal welding state registered in the memory 43 in advance, and if the difference value is equal to or smaller than a predetermined value, the welding state Is determined to be normal.

  If there is uneven brightness around the welding mark, for example, even if the result processing unit 47 determines that the welding state is defective by the method of the first modification or the second modification, the welding state is obtained by executing this modification. Is determined to be normal.

  Next, the effect of the appearance inspection method of this embodiment will be described.

  According to the present embodiment, by utilizing the change in luminance of the sheet surface due to the adhesion between sheets or the presence or absence of a gap, the sheets in the welded part are in close contact without directly looking at the shape and characteristics of the welding marks. It can be determined according to the actual welding state of the product. As a result, the quality of the welded state can be more easily determined without being confused by the welding marks. In addition, inspection can be performed even if the photographing field of view is extended to a range where the entire sheet can be seen. As a result, in-line appearance inspection can be realized.

  In addition, even if the two stacked or folded sheets are welded with normal welding marks on the appearance, if there is a gap due to wrinkles at the time of welding, it can be determined as defective effective. In particular, if the shape of the bag is maintained and the adhesiveness of the sheet of the welded part is maintained, the product with the characteristic that does not need to know about the state of the welded part is not confused by the weld mark, and the difference in the shape of the welded part There is an effect that it is possible to prevent erroneous determination caused by.

  In the method disclosed in Patent Document 4, it is a precondition for detection that the bonded portion is planar. However, the necessity of welding is more important than the robustness of the welded portion, and maintaining the bag state is emphasized. This embodiment is effective in applications where the shape is often point-like.

  In the above-described embodiment, the configuration of the appearance inspection apparatus has been described in detail in order to explain the appearance inspection method of the present invention in an easy-to-understand manner, but the features necessary for the appearance inspection apparatus for executing the appearance inspection method of the present invention are as follows. The configuration will be briefly described.

  FIG. 7 is a block diagram showing a configuration example of an appearance inspection apparatus according to an embodiment of the present invention. As shown in FIG. 7, the appearance inspection apparatus 140 includes an imaging unit 141, a holding unit 142, and a determination unit 143.

  When comparing the appearance inspection apparatus shown in FIG. 7 and the appearance inspection apparatus shown in FIG. 3, the photographing means 141 corresponds to the camera 1 and the image input unit 41, and the holding means 142 corresponds to the memory 43. Means 143 corresponds to the image processing unit 44 and the result processing unit 47. Since each configuration shown in FIG. 7 has been described with reference to FIG. 3, detailed description thereof will be omitted here.

  The present invention can be applied to an apparatus and a method for visually inspecting the quality of a state in which a sheet-like material and a film-like material for the purpose of packaging foods, drugs, and electronic components are heat-welded.

DESCRIPTION OF SYMBOLS 1 Camera 2 Illumination 3 Stage 4 Information processing apparatus 14 Inspection control part 43 Memory 46 Display part 47 Result processing part 140 Appearance inspection apparatus 141 Imaging | photography means 142 Holding means 143 Determination means

Claims (7)

A visual inspection apparatus for determining whether or not welding is performed in a process of sandwiching a plate-like object between two sheets having a property of partially transmitting light irradiated on a surface and welding the periphery to form a bag. ,
Imaging means for imaging in a state of irradiating the welded inspection object with uniform diffused light and converting it into image data;
The first reference luminance, which is the luminance of the sheet surface in an image taken by irradiating the diffused light on the surface of one sheet, and the diffused light in a state where the two sheets are stacked and normally welded Holding means for preliminarily holding a second reference luminance that is the luminance of the sheet surface in an image taken by irradiating
The determination target luminance, which is the luminance of the inspection region in the image captured by the imaging unit, of the inspection target irradiated with the diffused light is compared with the first and second reference luminances, and the determination target luminance and the second When the difference between the reference luminance and the first reference luminance is within a predetermined range, the welding state of the inspection region is determined to be normal, and the difference between the reference luminance and the first reference luminance is within the predetermined range, Determining means for determining that the welded state of the inspection region is defective;
Visual inspection apparatus having The appearance inspection apparatus according to claim 1,
The holding means is
First holding a first allowable range that is an allowable range of the first reference luminance and a second allowable range that is an allowable range of the second reference luminance;
The determination means includes
When the difference between the determination target luminance and the second reference luminance is within the second allowable range, it is determined that the welding state of the inspection region is normal, and the determination target luminance and the second reference luminance are Is larger than the second allowable range, and the difference between the determination target luminance and the first reference luminance is within the first allowable range, it is determined that the welded state of the inspection region is defective. Appearance inspection device. The appearance inspection apparatus according to claim 1 or 2,
The visual inspection apparatus, wherein the determination unit sets the determination target luminance to an average luminance of a region set in advance with reference to a contour or a corner of the sheet. The appearance inspection apparatus according to claim 1 or 2,
The appearance inspection apparatus, wherein the determination unit sets the determination target luminance to a mode value in which a luminance distribution frequency of a region set in advance with reference to a contour or a corner of the sheet is a maximum. The appearance inspection apparatus according to claim 1 or 2,
When the determination unit determines that the welding state of the inspection region is defective, the variation value of the luminance value in a predetermined coordinate range of the region set in advance with reference to the contour or corner of the sheet is set in advance as a normal welding state. An appearance inspection apparatus that calculates a difference from a registered fluctuation characteristic and determines that the welding state is normal if the calculated difference value is equal to or less than a predetermined value. A visual inspection method for determining the quality of welding in a process of sandwiching a plate-like object between two sheets having the property of partially transmitting light irradiated on the surface, and welding the surroundings to form a bag. ,
The first reference luminance, which is the luminance of the sheet surface in an image photographed by irradiating uniform diffused light on the surface of one sheet, and the diffusion in a state where the two sheets are stacked and normally welded Preparing a second reference luminance which is the luminance of the sheet surface in an image taken by irradiating light,
What is photographed in a state of irradiating the diffused light to the inspection object on which the sheet is stacked and welded, is converted into image data,
The determination target luminance that is the luminance of the inspection region in the image obtained by photographing the inspection target irradiated with the diffused light is compared with the first and second reference luminances, and the determination target luminance and the second reference luminance are If the difference is within a predetermined range, the welding state of the inspection area is determined to be normal, and if the difference between the determination target luminance and the first reference luminance is within the predetermined range, An appearance inspection method for determining that the welding state is defective. The computer executes a process for determining whether or not the welding is good in the step of sandwiching a plate-like object between two sheets having the property of partially transmitting the light irradiated on the surface, and welding the periphery to form a bag. A program for
In the computer,
The first reference luminance, which is the luminance of the sheet surface in an image photographed by irradiating uniform diffused light on the surface of one sheet, and the diffusion in a state where the two sheets are stacked and normally welded A procedure for storing a second reference luminance that is a luminance of a sheet surface in an image taken by irradiating light;
A procedure for converting what is photographed in a state of irradiating the diffused light to the inspection object on which the sheets are stacked and welded, and
The determination target luminance that is the luminance of the inspection region in the image obtained by photographing the inspection target irradiated with the diffused light is compared with the first and second reference luminances, and the determination target luminance and the second reference luminance are If the difference is within a predetermined range, the welding state of the inspection area is determined to be normal, and if the difference between the determination target luminance and the first reference luminance is within the predetermined range, A program for executing a procedure for determining that the welding state is defective.

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