JPS63130292A - Image measuring instrument - Google Patents

Abstract

PURPOSE:To improve the resolving power in X-axis and Y-axis directions and to simplify constitution by determining the central point coordinate of the refference circle mark on an object to be measured by line sensors disposed to an X-Y cruciform shape. CONSTITUTION:The coordinate at the central point P of a reference hole A are determined by determining the coordinates at the respective central points E, F of segments ab, cd if the detection segment in the X-axis direction of the reference hold A of a work W is the chord of ab, and the detection segment in the Y-axis direction is cd. On the other hand, the coordinates of the reference point G which is the crossed point of the line sensor 3 in the X-axis direction and the line sensor 5 in the Y-axis direction are preset as the origin coordinates. The difference between the coordinates at the central point P of the reference hole A and the coordinates at the reference point G is determined. This calculated value of the difference is an offset quantity as an error if work clamping position. The offset quantity is further converted to a number of pulses and said pulses are outputted to an NC console 9. The converted number of the pulses is outputted from an INC interface 25 to the NC console 9. The high resolving power is thus obtd. in the case of using the line sensors 3, 5.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to an image measuring device.

(Prior art) For example, in combined processing using a punching machine with NG and a laser processing machine with NC, the workpiece is re-clamped with a clamper after punching and before starting laser processing.
The workpiece is clamped at a clamping position convenient for laser processing.

However, when re-clamping the workpiece in this manner, it is inevitable that the clamping position of the workpiece will deviate slightly from the normal position. Therefore, the offset amount is automatically calculated to determine how far the new lamp position deviates from the regular clamp position, and the obtained offset amount is fed back to the NCH position on the processing machine side. And NG of the processing machine
The table device needs to correct the position coordinates of the workpiece based on the given offset Ω so that processing can be performed at the correct position.

However, conventionally, there is generally no known device that automatically calculates the offset amount of the lamp position and feeds it back for correcting the clamp position of the workpiece.

Therefore, a reference circle such as a reference hole or mark is provided on the workpiece to be measured, and an area sensor is mounted on the COD camera as an imaging means to detect the reference circle on the workpiece clamped by the clamper. Transport the image. Then, the center point coordinates (X+, Y+) of the reference circle are calculated from this image signal, and the camera center point coordinates (Xo
, Yo ), and the difference (Xo −X+ , Y
o −Y+). A conceivable image measuring device is such that this difference is converted into a pulse number and given to the NC console on the processing machine side as the offset amount of the workpiece, and the clamping position of the workpiece is automatically corrected on the processing machine side.

(Problem to be Solved by the Invention) However, in the case of an image measuring device that uses an area sensor in the COD camera of the imaging means to determine the coordinates of the center point of the reference circle of the object to be measured, the area sensor is Due to yield issues, it is common to divide the area into approximately 512 x 480 pixels, and when using non-interlaced scanning, it is even coarser and splits into 2 pixels.
It will be divided into 56x240. Therefore, the field of view of the camera was changed to 5 m.
If it is x5mm, it is about 0.02mm per pixel.
This is the minimum detectable size.

Therefore, when such a camera with a built-in CCD area sensor is used, there is a problem that detection on the micron order is not possible within the currently required field of view.

This invention was made in view of these considerations, and uses line lenses arranged in an XY cross pattern as an imaging means, making it possible to accurately calculate the coordinates of the center point of the reference circle on the object to be measured. The purpose of this invention is to provide an image measuring device that can be used in various ways.

[Structure of the invention]

(Means for Solving the Problems) The image measuring device of the present invention includes an imaging means equipped with line sensors arranged in an XY cross pattern, and a binarization means for performing binarization processing on an image signal of the imaging means. Then, from the binarized data of the image signal of the reference mark on the object to be measured, move the reference mark in the X-axis direction and Y
The apparatus includes calculation means for determining the coordinates of the midpoint of each chord cut in the axial direction and using these X and Y coordinate values as the coordinates of the center point of the reference mark.

(Function) In the image measuring device of the present invention, the line sensors arranged in the XY cross of the imaging means respectively scan the reference circles on the object to be measured in the X-axis direction and the Y-axis direction. The coordinates of the center point of the reference circle can be calculated from the binarized signal obtained by binarizing the filling signal of the line sensor.

(Embodiment) FIG. 1 shows a block diagram of an embodiment of the present invention, and FIG. 2 shows the system configuration.

As shown in FIG. 2, the workpiece W has been punched and is clamped at a predetermined position by a clamper (not shown) for laser processing.

The CCD camera 1 as an imaging means has built-in line sensors 3 and 5 arranged in an XY cross pattern as shown in FIG. Performs scanning in the Y-axis direction. Each of the line sensors 3 and 5 is normally one with 2048 pixels, but it is also possible to use one with 4096 pixels if necessary. Furthermore, if necessary, the 2048-pixel line sensor can be divided into 2-pixel units and 4-pixel units for use.

The image processing device 7 includes a line sensor 3 of the CCD camera 1,
The image signal from No. 5 is binarized, and the center point coordinates (Xl.

Y+), and the coordinates of the camera center as the origin (Xo
, Yo) and the difference (Xo −X+).

The offset amount of the clamp of the workpiece is calculated from Yo −Y+ ). Further, the image processing device 7 converts the obtained offset value into a pulse number and outputs it to the NC console 9.

A terminal 11 is connected to this image processing device 7. This terminal 11 is not necessary in normal use, but is used when it is necessary to refer to the internal memory of the image processing device 7 for test runs or the like.

The NC console 9 is for controlling the entire laser cutting process, for example.

The circuit configuration of this embodiment will be explained based on the block diagram shown in FIG. 1. The image processing device 7 has a CPU 13 as arithmetic means for controlling the entire device, and RAM 15, ROM 17. It includes a binarization circuit 19 as a binarization means, an image capture control circuit 21, a communication interface 23, an NC interface 25, and an image carrier interface 27.

The RAM 15 is used to store binary data of image pickup signals, and is also used as a buffer for various communications.

, ROM 17 stores a control program.

The binarization circuit 19 is for converting the imaging signal into binarized data.

The image capture control circuit 21 has an image transfer interface 27
This is a circuit that commands the start and stop of the

The communication interface 23 is in charge of coordination when connecting with the terminal 11.

The NC interface 25 is an interface with the NG console 9.

The imaging interface 21 receives the R image signal, the X axis,
This is for transmitting a Y-axis switching signal and an image scanning clock pulse.

The terminal 11 is used to view or change the contents of the ROM 17, or to forcibly issue commands to the image processing device 7.

The operation of the image J1 measuring device having the above configuration will be described next.

4 and 5, in response to a command from the image capture control circuit 21 of the image processing device 7, a start signal is sent to the CCO camera 1 via the imaging interface 27, and the COD camera 1 The axial direction line sensor 3 and the Y-axis direction line sensor 5 detect the workpiece W in the X-axis direction and Y-axis direction.
Begin axial scanning.

This imaging is controlled by the image capture control circuit 21. First, the image signal from the line sensor 3 in the X-axis direction is captured into the binarization circuit 19, converted to binarized data, and then
M15 (step 31.32>).

Subsequently, the image signal from the line sensor 5 in the Y-axis direction is
It is taken into the digitization circuit 19, converted to binarized data, and R
It is taken into AM15 (steps 33 and 34>).

From the binarized data imported into the RAM 15 in this way, 119 data in the X-axis direction and Y-axis direction of the Jut hole A of the workpiece W are extracted, and the coordinates of the center point P (Xl.

Y+) is calculated by the following procedure.

In other words, as shown in FIG.
The detected line segment in the axial direction is ab, and the detected line segment in the Y-axis direction is cd.
Suppose that the string is Then, by finding the coordinates of the midpoints E and F of these line segments ab and cd, respectively, the coordinates (X+, Y+) of the center point P of the reference hole A can be found.

On the other hand, the coordinates (Xo, Yo
) are set in advance as origin coordinates.

Therefore, the coordinates of the center point P to this reference hole (×1°Y+
) and the coordinates (Xo, Yo) of the reference point G (Xo
−X+ , Yo −Yr ). This count value is the offset as an error in the clamp position of the workpiece (step 35).

The offset term thus obtained is further converted into a pulse number and output to the NG console 9 (step 36).

This pulse number conversion value is as follows.

In other words, if the converted value of the number of pulses per pixel is α, then X-axis direction: (Xo -X+)Xα Y-axis direction: (Yo Y+)Xα And this pulse number converted value is
is output to the NO console 9 (steps 37 and 38>).

Here, the number of pixels of each line sensor 3, 5 is 2048
When the decoy field of view is 5 mm, the resolution is 5+nm÷2048': 0.0025 mm.

Therefore, in the case of the COD camera 1 using the line sensors 3 and 5, a resolution that is approximately one order of magnitude higher can be obtained than in the case of using an area sensor.

Further, when performing image processing using an area sensor, the memory capacity required to store image pixel data is 64 pixels in the case of 256×256 division, and 256 pixels in the case of 512×512 division.

However, in the case of this embodiment, since a line sensor is used, even if one divided into 2048 is used,
Only 2048 pixels are required in each of the axial direction and the Y-axis direction, which is the number of pixel divisions at most. Therefore, the software i for calculating the offset maximum is
・Both hardware and hardware can be significantly simplified.

In this embodiment, line sensors 3 and 5 having 2048 pixels are used, but the number of pixel divisions of the line sensors is not particularly limited. Therefore, it is also possible to use the currently available 4096 pixel image.

Also, for the 2048 pixel line sensor, 1
Not only can you use it in units of pixel, but you can also use it in units of 2 pixels,
It can also be used in units of 4 pixels. When used in units of 2 or 4 pixels like this, the field of view is 5 m.
In the case of rrl, the accuracy is 0, OO5mm, and 0, respectively.
, 01 mm. Therefore, it is possible to easily set the accuracy according to the purpose of detection.

Roughly speaking, in the above embodiment, the reference hole A was specially provided on the workpiece W to serve as a reference, but this reference hole was not made special.
1 with punching! ? The offset distance may be calculated from the difference between the regular center point coordinates and the actual center point coordinates at the time of clamping, using a machined hole. Alternatively, a circle mark may simply be attached and this may be used as a reference circle mark.

〔Effect of the invention〕

Since the present invention has the above configuration, the coordinates of the center point of the reference circle of the object to be measured can be automatically calculated. Moreover, since the coordinates of the center point of the MQ circle mark on the object to be measured are determined using the inner sensor arranged in the XY cross, the
The axial resolution can be improved, and at the same time, the memory capacity required to store image pixel data can be significantly reduced, and the configuration can be simplified.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a system configuration diagram of the above embodiment, Fig. 3 is a layout diagram of a line sensor of a CCD camera in the above embodiment, and Fig. 4 is a diagram of the above embodiment. FIG. 5 is an explanatory diagram illustrating the operation of introducing the offset stiffness in the above embodiment. 1... CCD camera 3.5... Line sensor 1 Noah... Image processing 1! I! Device 9...NC console 13...CPU 1...Binarization circuit agent Patent attorney Yasuo Miyoshi Figure 2 Hatake 3A Figure 4 Figure 5

Claims (1)

[Claims] An imaging means equipped with line sensors arranged in an XY cross pattern, a binarization means for binarizing the imaging signal of the imaging means, and a binarization data of the imaging signal of the reference mark on the object to be measured. Calculating means for determining the coordinates of the midpoint of each chord that cuts the reference mark in the X-axis direction and the Y-axis direction, and determining these X-coordinate values and Y-coordinate values as the coordinates of the center point of the reference mark. Image measurement device.