JPH0438517B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a two-dimensional laser processing method with computer numerical control (CNC) and its laser processing system, and in particular to image processing of figures and objects indicating a processing line and image processing. This paper relates to a laser processing method and its laser processing system for automatically creating computer numerical control (CNC) operating programs.

Conventional technology Conventionally, computer numerical control (CNC)
The attached laser processing machine has been widely used, especially in the field of cutting thin metals and non-metals. Laser processing machines related to such conventional technology require the creation of computer numerical control (CNC) operating programs, so operators who are capable of creating computer numerical control (CNC) operating programs are required to It was necessary to create an operating program for each.

Problems that the invention attempts to solve However, computer numerical control (CNC)
When creating an operation program, it is necessary to calculate the coordinates of the shape to be laser-processed in advance, so when creating an operation program that processes complex or irregular shapes,
Complex calculations must be performed across all machining lines to calculate figure coordinates. Therefore, a lot of manpower and time were required in the setup stage before starting laser processing.

In addition, laser processing for mass production of a single type is profitable even if it requires a lot of manpower and time at the setup stage, but in a flexible manufacturing system (FMS) for high-mix low-volume production, the setup If a large amount of manpower and time were required at each stage, not only would it be unprofitable, but the Flexible Manufacturing System (FMS) itself would not be viable.

The present invention was made against the background of the above-mentioned circumstances, and uses an imaging means to non-contactly read a figure representing a processing line or an actual object in a laser processing machine equipped with computer numerical control (CNC), and perform image processing. The purpose of the present invention is to provide a laser processing system that realizes a laser processing method that converts into a computer numerical control (CNC) operating program.

Means for Solving the Problems The present invention solves the above-mentioned problems by providing a laser processing method using a visual aid, in which step A...photographs a two-dimensional figure and object representing the processing line; Obtain the original gray value image, B step...process the original gray value image to obtain a threshold processed image with enhanced contrast, C step... obtain the threshold processed image A mode to extract the outline of the image Select one of the following three selection modes: (a) a mode for extracting the skeleton lines of the image, (c) a mode for extracting the outline and skeleton lines of the image, and set the extraction of each processing line. According to the processing line extraction mode, each processing line is extracted as coordinate data by the coordinates added from left to right and from top to bottom in the threshold-processed image, and E step...extracted as coordinate data. The processed processing lines are smoothly arranged and filed, F step...The coordinate array of each processed processing line that has been filed is converted into coordinate vector data, and G step...The coordinate arrangement of each processing line that has been converted into coordinate vector data is The start and end points of machining are set for the H step...The optimum machining path is set so that the coordinate vector of each machining line is machined from the inside to the outside based on the start and end points of machining. I step...Converts the coordinate vector data of each processing line set as above into a computer numerical control (CNC) operating program, and inputs it to the computer numerical control (CNC) control device to start processing on the laser beam machine. The problem can be solved by a visually assisted laser processing method consisting of steps of controlling the path and performing laser processing.

In a preferred embodiment of the present invention, in step C, when contour line extraction is set, the inside of the contour line is filled with a predetermined gray value different from the minimum gray value of the threshold-processed image, and the skeleton line extraction setting is When doing so, it is convenient to maintain the minimum gray value as is.

Similarly, the present invention solves the problem by providing an apparatus for laser processing using a visual aid means, which uses an imaging means for taking a two-dimensional image of a figure and object indicating a processing line, and a microcomputer. It consists of an image processing means that performs processing, a computer numerical control (CNC) control device, and a laser processing machine, and the image processing means is equipped with an image display device and an operation keyboard, and converts analog images into digital images. a digital image generation circuit for temporarily storing the digital image; a display logic circuit for displaying the digital image on the image display device; It consists of an image vector coordinate conversion circuit that converts into vector data, a program that performs imaging, a program that thresholds the two-dimensional image obtained by the imaging means, and selects and extracts contour lines and skeleton lines as processing lines. The present invention is solved by a visually assisted laser machining method characterized by comprising a program for converting coordinate data into coordinate vector data, and a program for setting a start point and an end point of machining.

In a preferred embodiment of the present invention, the imaging means is advantageously a solid-state camera using a charge-coupled device (CCD) as a solid-state imaging device.

Function: The visually assisted laser processing method according to the present invention employs image processing methods such as the above-mentioned A to I steps in its image processing. Obtain it as a two-dimensional image using an imaging means,
It is almost automatically converted into a computer numerical control (CNC) operating program while performing the necessary processing.
The laser processing machine is controlled via a computer numerical control (CNC) control device to perform the necessary laser processing. Therefore, the complicated and time-consuming procedure of calculating figure coordinates can be omitted.
A flexible production system (FMS) that can complete a two-dimensional laser processing machine operating program in an extremely short period of time, allowing you to perform many types of processing in small quantities.
It can also be fully accommodated.

Note that when the contour line is set to be extracted in the C step, by filling the contour line with different gray values, it can be easily identified when the coordinate data is extracted for each machining line in the next step.

In addition, in the laser processing device according to the present invention, in an image processing means centered on a microcomputer, an imaging means such as a CCD solid-state camera with little image distortion is activated by a program for imaging, and the processed figure or An object representing a processed figure is imaged and converted into a digital image signal by a digital image generation circuit, and an original gray value image is displayed on an image display device. This original gray value image is converted into a threshold-processed image with enhanced contrast using a threshold-processing program, and is displayed on an image display device. Next, while viewing this threshold-processed image on an image display device, settings for extracting processing lines are made using a program that selects and extracts contour lines and skeleton lines as processing lines. According to this processing line extraction setting, processing lines are extracted as coordinate data using coordinates added in order from left to right and from top to bottom of the threshold-processed image. The machining lines taken out as coordinate data are arranged smoothly without breaks or intersections, and only each machining line represented by this coordinate data is filed and stored in an external storage device attached to a microcomputer. The coordinate data of each filed processing line is converted into coordinate vector data by a vectorization program. The start and end points of machining are set while viewing the image display device according to a program for setting the start and end points of machining for each machining line represented by this coordinate vector data. Next, the optimal machining path for each machining line is set according to a program that sets the optimal machining path so that the machining line processes from the inside to the outside.

The program that converts the coordinate vector data of the machining line obtained through the above image processing into a computer numerical control (CNC) operation program was once converted into a computer numerical control (CNC) operation program, and the computer numerical control (CNC) ) to control the operation of the laser processing machine and execute the necessary laser processing.

Embodiments Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 is a flowchart showing a visually assisted laser processing method according to the present invention, and FIG.
FIG. 3 is an explanatory diagram showing an example of a figure representing a processing line; FIG. 4 is an explanatory diagram showing a primitive gray value image; FIG. 5 is an explanatory diagram showing the distribution moments of gray values, FIG. 6 is an explanatory diagram showing a threshold-processed image, FIG. 7 is an explanatory diagram showing a machining line image from which machining lines are extracted, and FIG. The figure is an explanatory diagram showing a curve approximation processed image, and FIG.
FIG. 3 is an explanatory diagram showing a machining line image in which a machining start point, an end point, and an optimal machining path are set.

1 and 3 to 9, a visually assisted laser processing method according to the present invention will be explained.

In step A, the imaging execution program photographs a figure or object representing a processing line, such as the logo shown in FIG. 3, and converts it into a digital image, creating the two-dimensional original gray value image P shown in FIG.
Get 1. However, this original gray value image P1 generally has many intermediate gray values (referred to as threshold values in the present invention), as shown by the hatched area in FIG. Therefore, it is necessary to enhance the contrast and convert the image into an image with sharp outlines.

This image conversion is performed in the B step.

However, when general image conversion is performed, the image is deformed and the processing line cannot be faithfully restored, so the optimum threshold value t is determined using a program that calculates the optimum threshold value t. This optimal threshold is then combined with the maximum threshold (e.g., white) and the minimum threshold (e.g.,
It is necessary to perform threshold processing to sort the images into black and black.

The method for calculating the optimal threshold value t will be explained based on FIG. In the relationship between the gray value of 255 and the number of pixels shown on the Y axis, a distribution with moments as shown is obtained. In the figure, a portion T with a high density close to 0 indicates an image, and a portion S with a low density near 255 indicates the background of the image. Therefore,
If we calculate the optimal threshold value t at the intermediate position between T and S and perform threshold processing, the moment of the gray value distribution will be the same before and after the threshold processing, so as shown in Figure 6. A threshold-processed image P2 that faithfully restores the original image can be obtained.

In addition, in the present invention, a known method is employed in which a gray value located at an intermediate position of moments in which gray values are distributed is selected as a specific threshold value t and processed so that the moments of the gray value distribution before and after threshold processing are the same. Moment Preservation Thresholding Technology (Moment-P-
Since the threshold processing is performed by adopting the reserving Thresholding method (a method created by Tsinghua University in Taiwan) in the program for calculating the optimal threshold t,
The detailed calculation method will not be explained.

Next, in step C, the processing line extraction setting program extracts the image outline and skeleton lines from the threshold-processed image P2: One of the three modes is set, and the extraction setting of this processing line is determined depending on the content of the laser processing. In addition, the skeletal line of Modei is used to mean the line that represents the middle between the contours, and when it comes to the character part (mtc) inside the image, it looks just like the skeleton of a fish, so it is not a skeletal line. I'm calling.

Now, when setting the processing line to be extracted, when extracting the contour line (MODOR or C), convert the gray value inside the contour line extracted using the Contour-Filling method of known image processing technology. It can be seen that the contour line is extracted as a light density thing with an intermediate gray value.
When extracting the skeleton line, modei or u are extracted as is and the gray value is not changed. If you want to extract partial contour lines and partial skeleton lines (mode),
Set the contour area using a cursor, mouse, etc. and extract the processing line using the contour line. If the specified area of the contour line is not set, the machining line is automatically extracted using the skeleton line. Therefore, although not shown, to explain using FIG. 6, in this mode, the central character part p20 from which the outline has been extracted is filled with a pale gray value, and the skeleton is If the outer circle portion p21 from which the line is extracted maintains its original dark gray value, it can be clearly distinguished, which is convenient in selecting and setting the machining line and in the next processing.

In the D step, each machining line is extracted as coordinate data based on the x and y coordinates added in order from left to right and top to bottom of the screen, but it is difficult to determine whether it will be processed as a contour line or a skeleton line. are automatically distinguished by the gray value of that part. Contour tracking is a known technique for contour lines.
Using the tracing method, extract the pixels that make up the contour line as coordinate data. Regarding the skeleton line, the pixels forming the skeleton line are extracted as coordinate data using a thinning method, which is a known technique. FIG. 7 shows a machining line image P3 obtained by selecting the above mode and extracting the contour line for the character portion 20 and the skeleton line for the circle portion 21 in FIG. 6 as machining lines. Therefore, in the figure, p30 indicates the processing line for the character portion, and p31 indicates the processing line for the circle portion.

In the E step, up to the previous step, the entire image including the background has been processed, but each processing line is In addition to correcting the coordinate data of the machining lines so that they are arranged in the smoothest manner, from now on, image processing can be performed based only on the coordinate data that shows the smoothest arrangement of contour lines and skeleton lines.
Unnecessary data is deleted by filing each coordinate data.

In the F step, characteristic points p40 and p4 representing the characteristics of the curve are determined by a known curve approximation method for each coordinate data representing the smoothest filed arrangement.
1 respectively, and the selected feature points p40-
A curve approximation image P3 is obtained by converting p40, p41-p41 into a coordinate vector representing each machining line by a vector connecting them. In this way, each machining line, which used to be represented by a large number of bits, is replaced with a coordinate vector from feature point to feature point, making it possible to compress the amount of information and also can be easily converted into .

Note that the feature points p selected for each processing line
The coarse density of 40-p40 and p41-p41 is determined by the precision of processing. In other words, as shown in the figure, if very precision is not required, the feature point p
40-p41 and p40-p41 are taken at coarse intervals, and if precision machining is required, feature points p40-p40 and p41-p41 are taken at fine intervals.

Now, conventional laser processing systems have the disadvantage that in laser processing, for example, laser cutting, the start and end points of the cut are larger than the intermediate cutting width. The setting had a great influence on the quality of the cutting process, especially in laser cutting.

Therefore, in the G step, the feature point p
40-p41 has a primitive start point (that is, a primitive end point) in the coordinate order, so the primitive start point (original end point) of machining is automatically displayed for each machining line. In other words, regarding Figure 8, regarding the internal character part, the feature point p40 at the top left of the figure
is the primitive starting point (primitive starting point) of xy coordinates, and for the outer circle part, the feature point p41 on the right side of the center of the figure is the primitive starting point (primitive ending point) of xy coordinates.
It is.

Next, by operating a cursor or the like, start points (end points) K and L for each machining line are set at arbitrary points near the respective original start points (original end points). In the figure, the start point (end point) K, L is set at a point extending in the x-axis or y-axis direction from the primitive start point (original end point), but the start point (end point) K, It is also possible to set L. 8th
The figure shows a case where there are only two machining lines, but even if there are three or more machining lines, a start point (end point) is set for each machining line (not shown).

In step H, an optimum machining path is set based on the set start point (end point) so that machining progresses from the inside to the outside of the machining figure for each machining line.

In particular, in laser processing, since it is necessary to fix a thin plate-shaped workpiece on a processing table, processing must start from the innermost part of the processing figure and work sequentially outward. Therefore, for machining figures that have xy coordinates ordered from left to right and top to bottom, that is, from outside to inside, start points (end points) are set in reverse order from the end of the xy coordinates. By doing so, the arrangement is replaced from the inside to the outside, and the optimal machining path is set by replacing the machining path from clockwise to counterclockwise. To explain this with reference to Figure 9, the starting point (ending point)
For K and L, start machining from the later starting point (end point) K in terms of x and y coordinates, and
L comes after that. Processing route of each processing line
The optimum machining path is set so that the machining progresses in the opposite direction to the order of the xy coordinates and the machining is performed counterclockwise as shown by the arrow.

In step I, the coordinate vector data of each machining line set as described above is converted into a computer numerical control (CNC) operating program. It is desirable that this operating program takes into consideration the machining speed, and is input to a computer numerical control (CNC) control device to control the operation of the laser processing machine and execute laser processing of the set processing pattern using visual aids. .

Finally, if there is a next task, the process returns to step A and starts image processing using visual aids, and if there is no next task, the task is finished.

Hereinafter, an apparatus for visually assisted laser processing according to the present invention will be described.

In FIGS. 2, 3 to 9, an apparatus for visually assisted laser processing according to the present invention is an imaging means for photographing a figure representing a processing line and an object P to obtain a two-dimensional image of P. 1, and computer numerical control (CNC) necessary for image processing the two-dimensional image input from the imaging means 1 and laser processing.
an image processing means 2 mainly composed of a microcomputer in order to obtain an operating program; a CNC control device 3 into which a computer numerical control (CNC) operating program from the image processing means 2 is input;
It is comprised of a laser processing machine 4 that performs laser processing whose operation is controlled by a CNC control device 3 based on a computer numerical control (CNC) operating program.

The imaging means 1 employs a solid-state (CCD) camera using a charge-coupled device (CCD) as a solid-state imaging device. The reason why a solid-state (CCD) camera is adopted in the present invention is that a solid-state (CCD) camera is small and lightweight, and can provide images with less distortion. There is no problem even if other imaging means are used.

The image processing means 2 includes a computer 20 equipped with various processing programs necessary for the image processing of the present invention, and an image processing panel 21 that can be commercially available.
Image display device 25 generally called a display
and an image vector conversion circuit 26 that converts processing lines represented by coordinate data of pixels and gray values of each pixel into coordinate vector data representing each processing line.
and an operation keyboard 2 for making necessary mode settings and specifying with a cursor while looking at the image display device 25.
It consists of 7.

Therefore, the computer 20, which is equipped with the processing programs necessary to carry out each step of A to I as software, uses the digital image generation circuit 2.
2, an image temporary storage circuit 23, and a display logic circuit 24 are connected to a standard image processing panel 21, which converts the analog image signal obtained by the imaging means 1 using a solid-state (CCD) camera into a digital signal. The image generating circuit 22 converts the image into a digital image signal and stores it in the image temporary storage circuit 23, and displays the image on the image display device 25 via the display logic circuit 24. At this time, as shown in FIG. 4, what is displayed on the image display device 25 is a monotone atomic gray value image P1 having atomic gray values.

At this time, imaging is performed using a program (for example, selection and execution of the presence or absence of an image, the size of the image, the brightness of the image, etc.) for performing A-step imaging, which is provided in the computer 20A.

Next, the atomic gray value image P1 is transferred to the computer 20.
In addition to analyzing the distribution moment of the gray value using a program that performs B step threshold processing provided in The processed image P2 is stored in the image temporary storage circuit 23 and displayed on the image display device 25.

While looking at the threshold processing image P2, the take-out motor settings for the C and D step machining lines provided in the computer 20 are made based on the necessity of laser machining, and the contour line is set for each machining using the program that takes out the machining lines. Decide whether to extract the contour line or the skeleton line, and only for those that extract the contour line.
Converts the gray values in contour lines so that they can be distinguished from skeletal lines whose gray values are not converted. Note that in a color display, it is possible and desirable to display the inside of the outline in a different color.

The machining lines of the D step are extracted for each machining line from left to right and from top to bottom of the screen according to the xy coordinates, thereby obtaining the machining line image P3 shown in FIG. Note that the xy coordinates referred to in the present invention are, for example, as shown in FIG. 7, with the lower side of the display screen of the image display device 25 being the x axis and the left side being the y axis.

Regarding this machining line image P3, the coordinate data for displaying each machining line is arranged in the smoothest manner using a program provided in the computer 20 that smoothly arranges and files only the machining lines of the E step. Coordinate data for displaying each processing line is stored in an external storage device (not shown) such as a hard disk or floppy disk attached to the computer 20, and is also stored in the temporary image storage circuit 23.
The data of the entire image including the processing lines that was temporarily saved will be deleted. Note that filing to the external storage device and erasing the machining line image from the temporary storage circuit 23 is performed for each machining line.
For example, in FIG. 7, the circle portion p31 is first fired from the outside in the order of xy coordinates, and at the same time, the image data of this circle portion p31 is erased from the image temporary storage circuit 23. Next, the inner character portion p30 is filed and deleted from the image data temporary storage circuit 23 of this character portion p30.

The work of vectorizing the coordinate data of each machining line in the F step is carried out by a program provided in the microcomputer 20 that vectorizes the coordinate data of each machining line, and the feature points p40 and p41 are extracted using the curve approximation method described above. , each feature point p4
0-p40 and p41-p41 are connected by vectors. This not only greatly reduces the amount of information to be processed, but also allows it to be converted into an operating program for the laser processing machine 4.

The G step is performed by a program provided in the microcomputer 20 that sets a machining start point (end point) for the coordinate array of each machining line converted into coordinate vector data.

The program: 1. Displays the primitive start point (end point) using xy coordinates for each machining line; 2. Displays the machining start point (end point) for the primitive start point (end point) of each machining line. This is done in the following steps:

The H step is performed using a program provided in the microcomputer 20 to set the optimum machining path.

The I step uses a program provided in the microcomputer 20 to convert vector coordinate data that has undergone necessary processing into a computer numerical control (CNC) operating program, and a CNC signal conversion circuit 26 to convert the vector coordinate data to computer numerical control. (CNC) operation program,
For example, through a standard information transfer interface such as RS-232, the information is input to the CNC control device 3 to control the operation of the laser processing machine 4 and execute predetermined laser processing.

Effects of the Invention The visually assisted laser processing method and device according to the present invention include an imaging means and an image processing means.
Since the figures and objects representing the processing line can be directly converted into computer numerical control operating programs, the setup effort and time can be significantly reduced, and the system can be used in flexible production systems that perform high-mix, low-volume production.

In addition, the visually assisted laser processing method and apparatus according to the present invention use a CCD solid-state camera with low image distortion, and use a moment preservation threshold processing method in threshold processing, so that the original image can be faithfully reproduced. It is possible to provide a machining line that can be reproduced in detail, and when taking out the machining line, it is possible to automatically determine whether to take out according to the contour line or the skeleton line, so that reliable laser processing can be performed.

Furthermore, the laser processing apparatus according to the present invention is extremely practical because it is a combination of easily available and low-cost microcomputers, image processing devices, and the like.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing a laser processing method using visual aids according to the present invention, Fig. 2 is an overall configuration diagram showing an apparatus for laser processing using visual aids according to the present invention, and Fig. 3 is a diagram showing a processing line. An explanatory diagram showing an example, Fig. 4 is an explanatory diagram showing an ambiguous original gray value image, Fig. 5 is an explanatory diagram showing the gray value distribution moment, and Fig. 6 is an explanatory diagram showing a threshold-processed image. , Fig. 7 is an explanatory diagram showing the extracted machining line, Fig. 8 is an explanatory diagram showing the machining line subjected to curve approximation processing, and Fig. 9 is an explanatory diagram showing the machining line where the machining start point (end point) and optimum machining path are set. FIG. 2 is an explanatory diagram showing a processing line. (Main symbols in the drawing), 1...imaging means, 2...
...Image processing means, 3...CNC control device, 4...
Laser processing machine, 20...microcomputer,
21... Image processing panel, 22... Digital image generation circuit, 23... Image temporary storage circuit, 24...
... Display logic circuit, 25 ... Image display device, 26 ... Image vector coordinate conversion circuit, 27
...Operation keyboard, A to I...Each step related to the present invention, K, L...Start point (end point) of the processing line, S...Gray value distribution moment of the background part, T...Gray value of the image part Value distribution moment.

Claims (1)

[Scope of Claims] 1. A laser processing method using visual aid means, in which step A...photographs a two-dimensional figure and object representing a processing line to obtain a primitive gray value image, and step B...primitive gray value image. The value image is threshold-processed to obtain a threshold-processed image with enhanced contrast, and the C step...threshold-processed image is processed. Select one of the following three selection modes: a mode for extracting contour lines and skeleton lines, and set the extraction for each machining line; The processed image is defined by xy coordinates added from left to right and from top to bottom.
Each machining line is taken out as coordinate data, E step...each machining line taken out as coordinate data is arranged smoothly and filed, F step...each machining line filed as coordinate data is converted into coordinate vector data, G step ...Set the start point and end point of machining for the coordinate array of each machining line converted into coordinate vector data, and H step...set the coordinate vector of each machining line from the inside based on the start point and end point of machining. The optimum machining path is set to machine the outside, and the I step...The coordinate vector data of each machining line set as above is converted into a computer numerical control (CNC) operating program, and the computer numerical control (CNC) ) A visually assisted laser processing method comprising the steps of controlling the processing path of a laser processing machine by inputting the information to a control device of 1.) and executing laser processing. 2 The C step fills the inside of the contour with a predetermined gray value different from the minimum gray value of the threshold-processed image when the contour line extraction setting is made, and fills the inside of the contour line with a predetermined gray value different from the minimum gray value of the threshold-processed image, and when the skeleton line extraction setting is made, the inside of the contour line is filled with a predetermined gray value different from the minimum gray value of the threshold-processed image. Claim 1 characterized in that it is formed so as to maintain as it is.
Laser processing method with visual aids described. 3. A device for laser processing using visual aid means, comprising: an imaging means for taking two-dimensional images of figures and objects indicating a processing line; and an image processing means for performing image processing using a microcomputer; It is composed of a computer numerical control (CNC) control device and a laser processing machine, and the image processing means is equipped with an image display device and an operation keyboard, and a digital image generation circuit that converts an analog image into a digital image.
An image temporary storage circuit that temporarily stores digital images, a display logic circuit that displays them on a digital image display device, and an image vector coordinate conversion circuit that converts coordinate data of a processing line that has undergone necessary processing into coordinate vector data. A program that performs image capture, a program that performs threshold processing on the two-dimensional image obtained by the imaging means, a program that selects and extracts contour lines and skeleton lines as processing lines, and converts coordinate data into vector coordinate data. A program to set the start and end points of machining, a program to set the optimal machining path, and a program to convert vector coordinate data that has completed the necessary processing into a computer numerical control (CNC) operating program. A device for laser processing with visual aid, characterized by comprising: 4. The apparatus for visually assisted laser processing according to claim 3, wherein the imaging means is a solid-state camera using a charge-coupled device (CCD) as a solid-state imaging device.