CN100483283C - Two-dimensional positioning device based on machine vision - Google Patents

Abstract

The invention provides a 2D locator based on machine vision, comprising: digital camera fixed on machine tool, and processor connected with the digital camera; it selects geometric characteristics on workpiece as located object characteristics, the digital camera obtains digital image of the located object characteristic and transmits the digital image to the processor, the processor adopts image template matching algorithm to recognize the located object characteristics on the workpiece and calculates coordinates of the object location characteristics in visual field of the camera by edge detection algorithm and obtains coordinates of workpiece in the machine tool. And the invention is used in digital controlled machine and can implement automatic cutter alignment to replace the course of artificial cutter alignment.

Description

A kind of two-dimensional positioning device based on machine vision

Technical field

The present invention relates to computer numerical control technology, particularly a kind of two-dimensional positioning device based on machine vision.

Background technology

Machine vision adopts computer image processing technology, the geometric configuration of identifying object, and according to the geomery and the position coordinates of the proportionate relationship calculating object of the geometric properties of object and pixel.Numerically-controlled machine adds need determine the position of workpiece in lathe coordinate system man-hour, and present method is artificial tool setting, and this method efficient is low, bigger to technical level of operators and job morale dependence.

Summary of the invention

The object of the present invention is to provide a kind of two-dimensional positioning device, to overcome the deficiency of artificial tool setting mode based on machine vision.

Realize that technical scheme of the present invention is as follows: a kind of two-dimensional positioning device based on machine vision comprises the digital camera that is fixed on the lathe, the processor that links to each other with digital camera; Geometric properties on the selected workpiece is made the anchored object feature, described digital camera obtains the digital image information of this anchored object feature and is sent to processor, anchored object feature on the template matching algorithm identification workpiece of processor adopting image, adopt edge detection method to calculate the coordinate of described anchored object feature in viewing field of camera, obtain the coordinate of workpiece in lathe by coordinate transform.

As shown in Figure 1.Location geometric properties on the camera alignment pieces, these geometric properties can be circle, circular arc, right-angle side etc., the digital picture sending processor that photographs.Processor can be PC (PersonalComputer, personal computer) or IPC (Industrial Personal Computer, industrial personal computer) or embedded system.The physical dimension and the position coordinates of process software identification, calculating object, and be converted into the coordinate figure of workpiece coordinate system initial point in lathe coordinate system and give machine tool controller.

The coordinate transform mode as shown in Figure 2.Process software mates the digital picture and the geometric properties template of storage in advance, with the identification anchored object; According to the scale attributes and the edge detection algorithm of digital picture, try to achieve the phasor coordinate of location geometric properties in the visual field , the phasor coordinate of camera in lathe coordinate system

Read from the current coordinate of numerically-controlled machine by processor, then location geometric properties coordinate vector is on the workpiece:

$\stackrel{\→}{A}=\stackrel{\→}{C}+\stackrel{\→}{B}$

Can determine the position of workpiece in lathe coordinate system thus.

The present invention compared with prior art has following advantage:

(1) improved the location efficiency of numerically-controlled machine.

When employing was located based on the two-dimensional positioning device of machine vision, work efficiency greatly improved.

(2) bearing accuracy is not subjected to interference from human factor.

Based on the two-dimensional positioning device location good reproducibility of machine vision, position fixing process is finished by computing machine, and the mood when not being subjected to human factor such as operating personnel's technical merit and work is disturbed.

Description of drawings

Fig. 1 is the structured flowchart of apparatus of the present invention;

Fig. 2 is the coordinate transform synoptic diagram.

Embodiment

As shown in Figure 1, camera lens and camera connect firmly on numerically-controlled machine, and camera links by communication interface and processor.Anchored object feature on the workpiece is selected in advance, generally selects circle, right-angle side etc. for use, and its digital photo is pre-stored in the processor as template.To anchored object feature top, take pictures, and read digital photo by the processor instruction camera by the precalculated position mobile camera for lathe.Control program in the processor mates digital photo and template, identifies the anchored object feature in the digital photo, adopts edge detection method then, calculates the coordinate of this feature in digital photo.Anchored object feature shown in Figure 2 is a circle, and edge detection method can calculate the central coordinate of circle of this circle in digital photo, according to pixel and proportionate relationship in kind, can extrapolate the coordinate of this center of circle in viewing field of camera again.Viewing field of camera true origin shown in Figure 2 is defined in its upper left corner, and central coordinate of circle with vector representation is

Camera and lathe connect firmly, and the coordinate of the viewing field of camera upper left corner (initial point) in lathe coordinate system can read from the current location of digital control system, establish reading and are

Then the coordinate of this center of circle in the numerically-controlled machine coordinate system is:

$\stackrel{\→}{A}=\stackrel{\→}{C}+\stackrel{\→}{B}$

With this coordinate Be converted into the initial point of workpiece coordinate system, be sent to digital control system, can finish the automatic tool preset process.

Claims (2)

1, a kind of two-dimensional positioning device based on machine vision is characterized in that comprising the digital camera that is fixed on the lathe, the processor that links to each other with digital camera; Geometric properties on the selected workpiece is made the anchored object feature, described digital camera obtains the digital image information of this anchored object feature and is sent to processor, the template matching algorithm of processor adopting image compares digital picture that measures and the digital photo that is stored in the anchored object feature of processor in advance, thereby the anchored object feature on the identification workpiece, adopt edge detection algorithm to calculate the coordinate of described anchored object feature in viewing field of camera, obtain the coordinate of workpiece in lathe by the coordinate and the coordinate stack of camera in lathe coordinate system of the anchored object feature on the workpiece in viewing field of camera.

2, device according to claim 1 is characterized in that: the geometric properties of limit, hole or the arc profile of selection processing object is used for the identification of machine vision and asks for the coordinate position of workpiece at lathe as the anchored object feature.

Images