JP3805899B2 - Information recording method and apparatus for sheet metal products - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a method and an apparatus for recording information on a plate-shaped metal product, particularly suitable for application when directly marking information on a plate-shaped metal product having an effective part and an ineffective part.
[0002]
[Prior art]
For plate-shaped metal products, effective parts that are the original functional parts of the product, such as shadow masks and aperture grills used in color television CRTs, and lead frames used in the manufacture of semiconductors, and their peripheral parts. Some have both ineffective parts.
[0003]
For such a plate-shaped metal product, information on the product such as a product number is marked on the ineffective portion, and the information is automatically read and used in a later process.
[0004]
Thus, when marking information on the plate-shaped metal product, the position is generally specified in advance at the product design stage.
[0005]
[Problems to be solved by the invention]
However, since the surface state of the plate-shaped metal product is not always constant, there is a problem that the position specified at the time of product design is not optimal as the marking position for the marking method employed. There is.
[0006]
The present invention has been made to solve the above-described conventional problems. When information is directly marked on a plate-shaped metal product, it can be marked under optimum conditions for each product, so that the marked information is read reliably. It is an object of the present invention to provide a method and apparatus for recording information on a sheet metal product.
[0007]
[Means for Solving the Problems]
The present invention relates to a method for recording information on a plate-shaped metal product in which information is directly marked on an ineffective portion of the plate-shaped metal product having an effective portion and an ineffective portion. The binarized image is binarized using a predetermined threshold value, a binarized image in which noise having pixel values exceeding the threshold value is extracted is created, and based on the noise present in the ineffective portion of the binarized image The problem is solved by determining the marking position on the plate-shaped metal product.
[0008]
The present invention is also an information recording apparatus for a plate-shaped metal product that directly marks information on a non-effective portion of a plate-shaped metal product having an effective portion and an ineffective portion. A mounting table to be mounted, an image input means for inputting an image of the plate-shaped metal product on the mounting table, a means for generating a binarized image from the image input by the image input means, and the generated binary The non-effective portion of the digitized image is divided into windows of a predetermined size, and a noise area is calculated for each window, and the marking position on the sheet metal product is determined based on the calculated noise area. By comprising means for selecting a window, means for calculating a marking position on the sheet metal product from the position on the image of the selected window, and means for marking predetermined information at the calculated marking position As well as the above It is obtained by solving the problem.
[0009]
In other words, an image input means such as an area sensor or a line sensor is used to input an image of a plate-shaped metal product, and by binarizing the image data, a binarized image in which fine irregularities are extracted as noise is created. Since the marking position is determined based on the noise of the ineffective portion, the input image data is processed to avoid the effective portion of the product by image recognition, and the marking contents are easy to mark. It is possible to automatically select the marking position by making it possible to select a position where it is easy to recognize and to automatically recognize the position.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0011]
FIG. 1 is an explanatory diagram showing a schematic configuration of an information recording apparatus according to the first embodiment of the present invention.
[0012]
In the information recording apparatus of the present embodiment, a shadow mask (plate-shaped metal product) SM having an effective portion and an ineffective portion is placed at a reference position, and an X direction indicated by an arrow by a servo motor (moving means) (not shown). An X stage (mounting table) 10 that can be controlled to move at a constant speed, a line sensor camera (image input means) 12 that inputs an image from the shadow mask SM, and a shadow mask when the camera 12 inputs an image. An illumination device 14 that illuminates the surface of the SM and an image processing device 16 that processes image data input by the line sensor camera 12 are provided.
[0013]
The image processing device 16 divides a binarized image from the image input by the line sensor camera 12 and a non-valid portion of the generated binarized image into windows of a predetermined size, Means for calculating the noise area for each window; means for selecting a window corresponding to the marking position on the shadow mask SM based on the calculated noise area; and a shadow from the position of the selected window on the image. And a means for calculating a marking position on the mask SM.
[0014]
That is, although not shown, the position coordinate system of the X stage 10 (position coordinate system of the sheet metal product) is associated with the image coordinate system of the input image, and from the image coordinates of the selected window, The position coordinates of the marking position on the shadow mask SM are calculated.
[0015]
Further, in this information recording apparatus, a product information database 18 storing unique data for each product type, such as valid portion position data, used when the image processing apparatus 16 performs image processing, and the image processing apparatus 16 includes a controller 20 to which the marking position data calculated in 16 is input, and a marking device 22 for marking the position on the corresponding product based on the marking position data input by the controller 20.
[0016]
The image processing device 16 includes means for masking a range corresponding to the effective portion of the shadow mask SM in the image input by the line sensor camera 12 using data regarding the effective portion input from the database 18. is doing.
[0017]
In the present embodiment, each operation is executed as follows.
[0018]
First, the shadow mask SM is placed at a predetermined reference position on the X stage 10, and when the operation is started, the shadow mask SM moves from the shadow mask SM that moves at a constant speed in the direction of the arrow as the X stage 10 moves. In synchronization with the distance, for example, an image over the entire shadow mask SM is input to the image processing device 16 by the line sensor camera 12 that is scanned every 1 ms. The image data input in this way is sequentially stored in a frame memory in the image processing device 16.
[0019]
In the image processing device 16, image processing described in detail below is executed on the image data of the entire shadow mask SM read from the frame memory according to the flowchart shown in FIG. 2.
[0020]
However, in the first embodiment, a case where a two-dimensional code is directly marked by a laser marker (marking device) 22 at an appropriate position of an ineffective portion corresponding to the peripheral portion of the shadow mask SM is taken up.
[0021]
Therefore, the characteristics of marking two-dimensional information (characters, figures, two-dimensional codes, etc.) on a plate-shaped metal product such as a shadow mask will be described in advance by taking the case of laser marking a two-dimensional code as an example.
[0022]
A two-dimensional code that is directly laser-marked on the surface of a plate-shaped metal product is captured as an image by a CCD camera included in a two-dimensional code reader (not shown), converted into a binary image, and information is then obtained from the image by a decoder. Is automatically read out. In order to stably recognize such a two-dimensional code by a CCD camera, it is necessary to minimize noise as much as possible, so it is important to increase the S / N.
[0023]
However, since the plate-shaped metal product is rolled in the refining process, fine irregularities due to the rolling roller may occur on the surface. FIG. 3 is a plan view conceptually showing an enlarged state of the surface of the plate-like product having such irregularities and a cross-sectional view at the position AA ′. This plan view corresponds to a binarized image processed so that the flat portion is white.
[0024]
When a two-dimensional code is laser-marked on the surface of a plate-shaped metal product with such irregularities, even if the illumination conditions are optimized and the CCD camera captures the two-dimensional code as an image, the irregularities are noisy. The code may not be recognized from the image data input as a source. FIG. 4 conceptually shows an example of an input image obtained by such a CCD camera, in which scattered black portions are noise N, and a broken line C represents a two-dimensional code.
[0025]
Since the two-dimensional information marked on the plate-shaped metal product has the characteristics as described above, in the present embodiment, the image processing device 16 first smoothes the image data read from the frame memory. Process. This is a process for removing noise or the like that has entered an image due to optical or mechanical reasons to obtain more accurate image data, and a general processing method can be adopted.
[0026]
The effective portion in the image is masked using the effective portion position data related to the shadow mask SM input from the product information database 18 with respect to the image smoothed in step 1 (step 2). This will be described using a binarized image created by the following processing shown in FIG. 5. A large number of pores are formed by etching inside the ineffective portion Sa indicated by the black peripheral portion. This is a process for replacing the pixel value of the pixel located in the effective portion Sb, which is an area, with a constant pixel value equal to or higher than the threshold used for binarization so that the binarized image becomes white.
[0027]
Next, the image data masked in step 2 as described above is binarized to create a binarized image as shown in FIG. 5 (step 3). This image is a monochrome image by comparing the pixel values of all the pixels of the mask image with a predetermined threshold value and replacing pixels above the threshold value with 1 (white) and pixels below the threshold value with 0 (black). It is equivalent to creating. That is, it is shown in the reverse relation to the case of FIG.
[0028]
In FIG. 5, black in the ineffective portion Sa indicates that the surface is flat, and white is noise N that becomes an obstacle when inputting the image of the two-dimensional code, which is caused by unevenness existing on the surface. .
[0029]
As the binarization threshold value to be performed here, as described above, a binary image created in order to input a two-dimensional code into an image by a two-dimensional code reader (not shown) and decode the two-dimensional code from the image is used. It is desirable to use a threshold value used when creating the code and approach the conditions at the time of reading the code. In this case, it is desirable that the input conditions of the image by the line sensor camera 12 such as the specifications of the light source of the illumination device 14 shown in FIG. 1 be as close as possible to the image input system of the two-dimensional code reader.
[0030]
Next, as shown in FIG. 6, the ineffective portion Sa is indicated by a white frame, and a plurality of rectangles are overlapped thereon, and the ineffective portion is divided into rectangular windows W of a predetermined size (step 4). The total area of the noise N is obtained for each window W (step 5), and the window having the smallest obtained noise area is obtained and selected as the marking position. FIG. 7 shows an enlarged view of the presence of a plurality of noises in the rectangular ineffective portion thus divided into windows.
[0031]
By accurately associating the position and size of the window W with the marking position and size on the actual shadow mask SM, the noise component at the marking position can be faithfully reproduced, which causes noise at the marking position. Even when there is unevenness, it can be taken into account when decoding the two-dimensional code, so that the information reading accuracy can be improved.
[0032]
Here, when the ineffective portion Sa is divided into windows, the ineffective portion Sa is shifted by one window. However, if there is a time margin in the processing, for example, it may be shifted by half a window. By doing so, it is possible to further increase the marking position options.
[0033]
When the window having the smallest noise total area is selected in step 6, the position coordinates on the shadow mask corresponding to the window are obtained. As described above, the position coordinates on the shadow mask SM are previously associated with the coordinates on the X stage 10 where the shadow mask SM is placed at the reference position and the coordinates on the image input by the line sensor camera 12. Therefore, it can be easily calculated.
[0034]
When the position coordinates of the marking position on the shadow mask SM are determined by the calculation in this way, the coordinate data is output from the image processing device 16 to the controller 20, and the laser marker 22 is based on the input coordinate data. Is controlled, a two-dimensional code is marked on the shadow mask SM corresponding to the same coordinate.
[0035]
As described above in detail, according to the present embodiment, since the two-dimensional code can be laser-marked on the flatst surface in the ineffective portion Sa, writing of information is facilitated and written information Can be easily read by a two-dimensional code reader (not shown).
[0036]
Next, a second embodiment according to the present invention will be described.
[0037]
In the present embodiment, a laser marker or an ink jet device is used as the marking device 22 provided in the information recording apparatus shown in FIG. 1, and the barcode (one-dimensional information) is marked on the shadow mask SM. It is substantially the same as one embodiment.
[0038]
First, the characteristics of the barcode that marks the plate-shaped metal product will be described. In general, a barcode reader used to read information from a barcode usually irradiates the barcode with a light emitting unit using a semiconductor laser or an LED as a light source, and scattered light that is irregularly reflected by a white bar at that time. The code is read based on the received light amount data formed from the non-reflection of the black bar.
[0039]
FIG. 8A schematically shows the black and white bar code, and the normal read data (received light amount data) obtained for this bar code can be shown as in FIG. Since the difference in the amount of received light between black and white is clear, it can be reliably recognized.
[0040]
However, when the product is a plate-like metal and its surface is close to a mirror surface state, it is theoretically difficult to optically read a bar code written directly on the metal surface with an inkjet device or a laser marker.
[0041]
That is, FIG. 9 conceptually shows a state in which the barcode B printed on the surface of the shadow mask SM is read by the barcode reader 30 and used. Since the light projecting unit that irradiates the light and the light receiving unit composed of a CCD or the like are not in a relation of receiving regular reflection, in the case of a mirror surface, the light is not condensed on the light receiving unit. For this reason, when the metal surface is in a mirror state, all incident light (laser light) is specularly reflected, so that the light receiving unit recognizes the reflection from the mirror surface as black, and FIG. As shown in FIG. 5, the contrast of the black and white bar cannot be obtained and the recognition is impossible.
[0042]
Therefore, when marking a barcode directly on a shadow mask (plate-shaped metal product), the surface should be easily diffusely reflected. Therefore, contrary to the first embodiment, it is preferable that there is more noise. become.
[0043]
Therefore, in this embodiment, when the barcode is marked on the shadow mask SM by the information recording apparatus shown in FIG. 1, the image processing apparatus 16 performs window selection according to the flowchart of FIG.
[0044]
That is, from step 1 to step 5, the noise area for each window is obtained by the same processing as the flowchart of the first embodiment shown in FIG. 2, but in step 6, the window having the largest noise area is obtained. The position on the shadow mask SM corresponding to this is selected as a marking position, and the barcode B is marked there.
[0045]
According to this embodiment, the barcode B can be automatically marked on the ineffective portion that is most easily read by the barcode reader 30.
[0046]
Although the present invention has been specifically described above, the present invention is not limited to that shown in the above embodiment, and various modifications can be made without departing from the scope of the invention.
[0047]
For example, in the above-described embodiment, the shadow mask SM is moved on the X stage. However, the shadow mask SM may be moved on a conveyor. The line sensor camera 12 may be moved at a constant speed, not limited to moving the shadow mask.
[0048]
Further, an image of a stationary shadow mask may be input by an area sensor instead of a line sensor camera. The two-dimensional information is not limited to the two-dimensional code, and may be a character or a figure.
[0049]
【The invention's effect】
As described above, according to the present invention, it is possible to mark information on a plate-shaped metal product at a position where it is easy to read information after marking.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a schematic configuration of an information recording apparatus according to a first embodiment of the present invention. FIG. 2 is a flowchart showing image processing logic according to the first embodiment. FIG. 4 is an explanatory diagram showing the characteristics of a two-dimensional code. FIG. 5 is an explanatory diagram showing a binary image of a shadow mask with an effective portion masked. FIG. 6 is an explanatory diagram showing window division of an ineffective portion. FIG. 7 is an explanatory view showing noise in an ineffective portion divided into windows. FIG. 8 is an explanatory view showing features of a bar code. FIG. 9 is another explanatory view showing features of the bar code. The flowchart which shows the logic of the image processing of embodiment.
DESCRIPTION OF SYMBOLS 10 ... X stage 12 ... Line sensor camera 14 ... Illuminating device 16 ... Image processing device 18 ... Product information database 20 ... Controller 22 ... Marking device 30 ... Barcode reader SM ... Shadow mask Sa ... Ineffective part Sb ... Effective part B ... barcode

Claims (8)

It is an information recording method on a sheet metal product that directly marks information on an ineffective part of a sheet metal product having an effective part and an ineffective part,
An image of a plate-shaped metal product is input, the input image is binarized using a predetermined threshold value, and a binarized image from which noise consisting of pixel values exceeding the threshold value is extracted is generated. A method for recording information on a plate-shaped metal product, wherein a marking position on the plate-shaped metal product is determined based on noise existing in an ineffective portion of the plate-shaped metal product. In claim 1,
The ineffective portion of the binarized image is divided into windows of a predetermined size, an area of noise is calculated for each window, a window is selected based on the area, and the marking is determined from the position of the selected window. A method for recording information on a sheet metal product, wherein the position is determined. In claim 2,
When marking two-dimensional information on a plate-shaped metal product, the marking position is determined from the position of the window having the smallest noise area. In claim 2,
When marking one-dimensional information on a plate-shaped metal product, the marking position is determined from the position of the window having the largest noise area. In claim 2,
Associating the position coordinate system of the sheet metal product with the image coordinate system of the input image, calculating the position coordinates of the marking position on the sheet metal product from the image coordinates of the selected window,
A method for recording information on a plate-shaped metal product, characterized in that marking means is moved to the calculated position coordinates of a marking position, and information is marked at the marking position. An information recording device for a sheet metal product that directly marks information on an ineffective part of a sheet metal product having an effective part and an ineffective part,
A mounting table for mounting the plate-shaped metal product at the reference position, an image input unit for inputting an image of the plate-shaped metal product on the mounting table, and a binarized image from the image input by the image input unit Means, a non-effective portion of the generated binarized image is divided into windows of a predetermined size, a noise area is calculated for each window, and the plate-like metal is calculated based on the calculated noise area A means for selecting a window corresponding to a marking position on the product, a means for calculating a marking position on the sheet metal product from a position on the image of the selected window, and marking predetermined information on the calculated marking position An information recording device for a plate-like metal product, comprising: In claim 6,
In the case where the image input means is a line sensor camera, an apparatus for recording information on a plate metal product, comprising means for moving the line sensor camera or the plate metal product at a constant speed. In claim 6,
A product information database in which data relating to the effective portion of the plate-shaped metal product is stored;
A plate metal product comprising means for masking a range corresponding to an effective portion of the plate metal product in the image input by the image input means using the same data input from the database. Information recording device.

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