JPH02227785A - Recognizing method for circular or rhombic mark - Google Patents

Abstract

PURPOSE:To identify a circular or rhombic mark by obtaining the XY coordinates of both end points of a mark in the X direction and obtaining the center of the mark after discriminating the quantity of the input mark data. CONSTITUTION:The white and black picture element numbers l1 and l2 set on an axis AA' are counted for a picture memory inputted via a camera. The coordinates x1 is defined when the axis AA' is moved to the right and the number l2 changes to 1 or more from 0, and the center of a black picture element is defined as y1=l1+l2/2 on the axis AA'. Then the center position of a black picture element is defined as y2=l'1+l'2/2 on the axis AA' and at positions of the value x2 obtained by subtracting 1 from the coordinates where the number l2 changes to 0 from 1 or more after the axis AA' is moved more the right. Thus the coordinates of both end points are decided for a mark in the X direction. An error is decided and processed when the difference between the pitch L between both ends and the set value L' exceeds a prescribed range. In such a constitution, the distance (pitch) between both end points is equal to the diameter of a circle or the diagonal angle of a rhomb even with a circle or a tilted rhomb. Thus a defect is decided if the pitch of the mark data on the camera input is larger than the original difference. As a result, a wrong center position is never calculated nor recognized.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is an electronic component mounting machine that recognizes marks on a printed circuit board and detects their positional deviations in order to place a child component onto a printed circuit board with high precision. This paper relates to a method for recognizing circle or diamond marks that improves the mark recognition rate by correcting the marks.

[Conventional technology]

FIG. 5 shows the relationship between the circle mark on the printed circuit board and the electronic components. For machines equipped with electronic components, check the relative position of the circle mark and electronic components.
X/ and Y/ are set as constant data, and the circle mark on the printed circuit board is recognized to recognize the variation X and Y of the printed circuit board, and the electronic component mounting position is corrected accordingly to ensure accurate mounting. Recognition of the circle mark is performed using memory information (shown in FIG. 6) of a black and white image inputted by a camera.

The conventional method for recognizing circle marks is as shown in Figure 6.
This is done by counting the number of background white pixels (bright) and black pixels (dark) of the circle mark recognition 5 stored in the image memory Φ. For example, if the number of white pixels on AA' is 41 and the number of black pixels is l, the center of the circle mark in the Y direction is calculated from the left end of the reference and is 1□+12/2.

In this way, the center of the zero yen mark on the printed board is recognized, the deviation of the printed board is corrected, and electronic components are mounted with high precision.

In addition, related devices of this type include [LS described in Senna Technology J May 1987 issue, pages 90-93]
There are I mounters, etc.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, when the data input from the camera is missing and the object is in a deformed state as shown in FIG. 7, the central position is incorrectly calculated. Also, as shown in Figure 8, there is a large deviation of the board,
In the case of a diamond mark, there was also a problem in which the center alignment was calculated incorrectly.

An object of the present invention is to provide a recognition method that can recognize the center of a mark even in the above-mentioned cases.

[Means to solve the problem]

The above object is achieved by employing a method of searching both end points of a mark in the X direction and determining its X-Y coordinates.

[Effect]

Even if it is a circle or a complicated diamond, the distance (pitch) between both end points
is equal to the diameter of a circle or the diagonal length of a rhombus, so if the pitch between the end points of the mark data input from the camera is significantly different from the original pitch, you can tell that the mark data is defective. There is no calculation or recognition of incorrect center position [Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

If the image memory input by the camera 2 is as shown in Fig. 1, then the numbers of white pixels (bright) and black pixels (dark) on the AA' axis are 11 and 112, respectively, as shown in the flowchart of Fig. 2. , move the AA' axis to the right until the number of black pixels is O.
The coordinate in the X direction that has changed from 1 or more, x1, or A at that time
The center alignment of the black pixel on the A thin axis is yl(-111+#2/2
). Furthermore, by moving the AA' axis to the right, the axis obtained by subtracting 1 from the coordinate in the X direction where the number of black pixels changed from 1 or more to 0 is x, and the axis of the center of the black pixel on the AA' thin axis at the x position is the axis ,V
2 (=l, '±12'/2). This means that the X and Y coordinates of both end points in the X direction of the mark have been found. If the difference exceeds an arbitrary range (±ΔL), it is treated as a data error. If the input mark data is deformed as shown in FIGS. 8 and 4, it is treated as a data error at this point, which has the effect of almost eliminating poor mounting accuracy due to erroneous recognition.

Mark data is normal (1,/-ΔL≦L≦L′+ΔL)
In this case, since the midpoint between the two end points is perpendicular to the center of the mark, the deviation of the printed circuit board is determined, and the mounting data is corrected based on this to accurately mount the electronic component.

〔Effect of the invention〕

According to the present invention, whether the mark is circular or diamond-shaped, it is possible to determine whether the input mark data is acceptable or not, and the center of the mark can be correctly recognized, so that electronic components can be mounted correctly.

[Brief explanation of the drawing]

FIGS. 1, 8, and 4 are diagrams showing the arrangement of one mark image in memory according to an embodiment of the present invention, and FIG. 2 is a flowchart of mark center recognition according to the present invention. FIG. 5 is a layout diagram showing the relationship between marks on the printed circuit board and electronic components. FIG. 6, FIG. 7, and FIG. 8 are layout diagrams of conventional mark images in memory. ■...Printed circuit board 2...Electronic components 8...
- Board mark 4...Familiarity memory 5...Mark image 6...Bright/dark (black and white) V-bell 7...Setting mark shape.

Claims (1)

[Claims] 1. In the method of determining the center alignment of a circle or diamond mark on a printed circuit board input from a camera,
A method for recognizing a circle or diamond mark, characterized by determining the XY coordinates of both end points in a direction, determining whether input mark data is acceptable or not, and then determining the center of the mark.