KR20090049720A - Method of the auto calibration for the laser vision system using x-y stage - Google Patents

Abstract

The present invention relates to a laser vision system (LVS) calibration automation method, and in particular, a calibration matrix can be derived using a calibration jig mounted on an XY stage driven according to a given command. The present invention relates to a method of automating an LCD calibration using an XY stage.

The present invention includes the steps of mounting an LVS including a laser light source unit and a camera module in front of a calibration jig installed in an X-Y stage; Inputting a calibration path designated to the X-Y stage; Moving the X-Y stage in the X direction or the Y direction according to the input path; When the stop signal is applied to the X-Y stage, extracting an image of a calibration jig by the LS on an arbitrary coordinate (x, y) of the stopped X-Y stage and detecting a singularity point; And storing the image, the singular point, and the arbitrary coordinates (x, y) as data, and deriving a calibration matrix based on the stored data. Characterized in that.

According to the present invention, it is possible to calibrate the high precision elves in a short time, and to process the position coordinates in the space and the position on the image with stable data, thereby improving the technical efficiency of working process using elves There is.

X-Y Stage, LVS, Calibration Jig, Calibration Matrix

Description

Ｘ―ＹMethod of the auto calibration for the laser vision system using X-Y stage}

The present invention relates to a laser vision system (LVS) calibration automation method, and more particularly, to derive a calibration matrix using a calibration jig mounted on an XY stage driven according to a given command. It is related with the automatic calibration of the LV using the XY stage.

Due to the advanced development of industrial technology and many improvements in the working environment, the phenomenon of avoiding the work under the harsh environment such as welding was widespread. For this reason, various automation equipments using robots have emerged for various tasks in harsh environments on behalf of workers.

In particular, welding in the shipbuilding field is largely the case that a large welding object is bent or a step is formed, it is necessary to take a lot of time and manpower to accurately detect such welding position to weld.

Recently, as part of efforts to solve this problem, welding automation using LVS (Laser Vision System) has emerged. ELV is a device including a laser light source (for example, a laser diode) for scanning light and a camera module for acquiring an image, and is an apparatus capable of image processing using the principle of optical triangular.

In order to measure an accurate welding position using the elves, it is essential that a pre elevation calibration process is preceded.

The LV calibration process finds a relationship of where arbitrary points in the actual three-dimensional space are located on the LV video image.

For precise calibration, it is necessary to know exactly the points in the three-dimensional space, and it is better to perform the calibration by collecting information about as many positions as possible.

FIG. 1 is a photograph showing a conventional calibration jig used in an LCD calibration. FIG. 1A is a photograph of a conventional calibration jig viewed from the upper right, and FIG. 1B is a photograph of a conventional calibration jig viewed from the front. Referring to (a) and (b) of FIG. 1, the conventional calibration jig includes a lower reference block 10 having a corresponding groove for each unit length (eg, 10 mm), and a corresponding groove of the lower reference block 10. It consists of an upper jig block 20 having a corresponding protrusion that can be fitted.

Conventional elevance calibration is the operator manually moves the upper jig block 20 by one section by hand, and after fitting the upper jig block 20 to the lower reference block 10, the elegance calibration Was performed.

By the way, the conventional calibration of the conventional LV took a lot of time, there was a problem of position constraints and deterioration of precision according to the corresponding groove unit length (eg 10 mm) section of the lower reference block 10, the operator manually Due to the mounting and mounting of the upper jig block 20, there was a problem that various errors can occur.

Accordingly, there is a need for an automated LCD calibration method that can measure within a short time and has high precision.

The present invention devised to solve the above problems is to provide a method for automation automation calibration that can measure within a short time, high precision, and stable data processing is a technical problem.

According to the spirit of the present invention for achieving the above technical problem, a) an LVS including a laser light source unit and a camera module is mounted in front of a calibration jig installed in an XY stage. ; b) inputting a calibration path designated to the X-Y stage; c) moving the X-Y stage in the X direction or the Y direction according to the input path; d) extracting an image of the calibration jig by the LS on the arbitrary coordinates (x, y) of the stopped X-Y stage and detecting a singularity when the stop signal is applied to the X-Y stage; e) storing the image, the singular point and the arbitrary coordinates (x, y) as data in step d); And f) deriving a calibration matrix from the data stored in step e). The calibration calibration method may be provided using an X-Y stage.

In a preferred embodiment, steps c), d) and e) may be repeatedly performed to store the data in an amount necessary for deriving the calibration matrix in step f).

The steps c), d), e) and f) may be automatically performed according to a commanded command when the calibration path is input in the b).

According to the present invention, it is possible to calibrate the high precision elves in a short time, and to process the position coordinates in the space and the position on the image with stable data, thereby improving the technical efficiency of working process using elves There is.

In order to fully understand the present invention, the advantages of the present invention, and the objects achieved by the present invention, reference should be made to the accompanying drawings in which preferred embodiments of the present invention are illustrated.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

2 is a flow chart showing an embodiment of an automatic calibration method using the XY stage according to the present invention, Figure 3 is an elbow in front of the calibration jig installed in the XY stage in the embodiment shown in FIG. It is a picture shown to explain the installation of the V.

2 to 3 will be described in accordance with a preferred embodiment according to the spirit of the present invention.

Referring to FIG. 2, an LVS including a laser light source unit and a camera module is mounted in front of a calibration jig installed in an X-Y stage (S200). In the step S200, a calibration block having a V block shape is mounted and fixed on the XY stage, which is a stage that can be driven in two axes ('X axis' in the horizontal direction and 'Y axis' in the vertical direction), and the front of the calibration jig is mounted. Install the laser light source and camera module in the At this time, the XY stage is a motor drive device that can move in the X-axis direction (horizontal direction), Y-axis direction (vertical direction) according to the commanded signal, such XY stage is a device well known to those skilled in the art, a motor having a conventional configuration , An encoder, a driving ball screw, a moving table, and the like. At this time, it is preferable to use a high-performance encoder for more accurate LCD calibration. In this embodiment, an encoder having a performance of 2000 steps / mm is used.

Referring to FIG. 3, a V-shaped block-shaped calibration jig is mounted and fixed on an X-Y stage, and a laser light source unit and a camera module are installed in front of the calibration jig. As a result, an image in which the light scanned by the laser light source unit is reflected on the calibration jig can be acquired by the camera module. Since the arrangement position of the laser light source unit and the camera module is well known to those skilled in the art, the description thereof is omitted.

Thereafter, a calibration path designated to the X-Y stage is input (S210).

The X-Y stage is moved in the X-axis direction or the Y-axis direction along the path input in the previous step (S210) (S220). The drive control of this X-Y stage can be explained by the conventional motor control method.

Thereafter, when a stop signal is applied to the X-Y stage, an image of a calibration jig is extracted on an arbitrary coordinate (x, y) of the X-Y stage on which the LV is stopped (S230). In the step S230, an image and a singularity (where the singularity is a 'laser pattern shape') for the calibration jig are obtained by using elves on the coordinates (x, y) on an arbitrary position where the XY stage is stopped. . In a preferred embodiment, the LV and the XY stage are synchronized with each other to move to the position where the XY stage is input, and at the same time, the image and the singularity of the calibration jig mounted on the XY stage are automatically displayed on the LV. Can be detected.

The image extracted in the previous step (S230), the detected singularity and the arbitrary coordinates (x, y) are stored as data (S240). In this step (S240), the image extracted in the previous step (S230), the detected singular point and the arbitrary coordinates (x, y) at the time of extracting the image after the data processing, it is possible to achieve a more stable data management. At this time, if the stored data is insufficient to derive a calibration matrix value, which is the purpose of the LV calibration, the above-described previous steps (S220, S230) and this step (S240) is satisfied until it can be satisfied. It is preferred to be repeated.

Thereafter, a calibration matrix is derived from the stored data (S250). In this step (S250), the 'calibration matrix' is a coordinate transformation-related matrix that can determine how any position on the two-dimensional image acquired in the elves is transformed in the three-dimensional space on the actual work. It is a purpose. As a preferred embodiment, the above-described steps (S220, S230, S240, S250) is preferably performed automatically through the command command in the step (S210) of inputting the calibration path to the X-Y stage.

Although the present invention has been described with reference to the embodiments shown in the accompanying drawings, it is merely an example, and those skilled in the art will understand that various modifications or equivalent other embodiments are possible therefrom. will be.

Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

FIG. 1 is a photograph showing a calibration jig used in a conventional LCD calibration.

Figure 2 is a flow diagram illustrating an embodiment of an automated LCD calibration using the X-Y stage in accordance with the present invention.

FIG. 3 is a photograph for explaining a state in which the elves are mounted in front of the calibration jig installed in the X-Y stage in the embodiment shown in FIG. 2.

Claims (3)

a) mounting an LVS including a laser light source unit and a camera module in front of a calibration jig installed in an X-Y stage; b) inputting a calibration path designated to the X-Y stage; c) moving the X-Y stage in the X direction or the Y direction according to the input path; d) extracting an image of the calibration jig by the LS on the arbitrary coordinates (x, y) of the stopped X-Y stage and detecting a singularity when the stop signal is applied to the X-Y stage; e) storing the image, the singular point and the arbitrary coordinates (x, y) as data in step d); And f) deriving a calibration matrix from the data stored in step e). How to automate calibration of LV using X-Y stage. The method of claim 1, Characterized in that the steps c), d) and e) are repeatedly performed to store the amount of data necessary for deriving the calibration matrix in step f). How to automate calibration of LV using X-Y stage. The method of claim 1, Step c), step d), step e) and step f), When the calibration path is input in the step b), characterized in that automatically proceeds in accordance with the command command, How to automate calibration of LV using X-Y stage.

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