阅读说明：本技术 一种管材测量标定方法 (Pipe measuring and calibrating method ) 是由 郑展鹏 罗锡阳 罗盛华 于 2019-09-12 设计创作，主要内容包括：本发明一实施例提供一种管材测量标定方法,其特征在于,包括：获取第一管材穿过光电开关时的第一管材端面的图像；其中,所述第一管材端面的图像由相机拍摄得到；获取第一管材穿过光电开关时激光头到所述第一管材端面的距离；其中,所述激光头到所述第一管材端面的距离为标定距离D；所述激光头到所述第一管材端面的距离D由激光测距仪测量得到；根据图像处理算法计算得到所述第一管材端面图像中的直径I；根据所述第一管材实际的直径与所述第一管材端面图像中的直径I,计算得到管材的标定转换系数E。本发明实施例能够得到标定转换系数,从而能够完成管材测量的标定,进而便于日后能够升级为自动获取管材的直径。(An embodiment of the present invention provides a pipe measurement calibration method, including: acquiring an image of the end face of the first pipe when the first pipe passes through the photoelectric switch; the image of the end face of the first pipe is shot by a camera; acquiring the distance from a laser head to the end face of a first pipe when the first pipe passes through a photoelectric switch; the distance from the laser head to the end face of the first pipe is a calibration distance D; the distance D from the laser head to the end face of the first pipe is measured by a laser distance meter; calculating according to an image processing algorithm to obtain the diameter I in the first pipe end face image; and calculating to obtain a calibration conversion coefficient E of the pipe according to the actual diameter of the first pipe and the diameter I in the end face image of the first pipe. The embodiment of the invention can obtain the calibration conversion coefficient, thereby completing the calibration of the pipe measurement, and further facilitating the future upgrading to automatically acquiring the diameter of the pipe.)

1. A pipe measurement calibration method is characterized by comprising the following steps:

acquiring an image of the end face of the first pipe when the first pipe passes through the photoelectric switch; the image of the end face of the first pipe is shot by a camera;

acquiring the distance from a laser head to the end face of a first pipe when the first pipe passes through a photoelectric switch; the distance from the laser head to the end face of the first pipe is a calibration distance D; the distance D from the laser head to the end face of the first pipe is measured by a laser distance meter;

calculating to obtain the diameter I in the image of the end face of the first pipe according to an image processing algorithm;

and calculating to obtain a calibration conversion coefficient E of the pipe according to the actual diameter of the first pipe and the diameter I in the image of the end face of the first pipe.

2. The pipe measurement calibration method according to claim 1, wherein the conversion coefficient E is determined by the following formula:

E＝I/R

wherein E is a calibration conversion coefficient, I is the diameter of the end face of the first pipe in the image, and R is the actual diameter of the first pipe.

3. A method for obtaining the diameter of the pipe according to the pipe measurement calibration method of claim 2, which comprises:

acquiring an image of the end face of the second pipe when the second pipe passes through the photoelectric switch;

obtaining the distance D2 between the laser head and the end face of the second pipe when the second pipe passes through the photoelectric switch;

calculating the diameter I2 of the image of the end face of the second pipe according to an image processing algorithm;

calculating to obtain a conversion coefficient E2 according to the calibration conversion coefficient E, the calibration distance D and the distance D2 from the laser head to the end face of the second pipe;

and calculating the actual diameter of the second pipe according to the diameter I2 of the image of the end face of the second pipe and a conversion coefficient E2.

4. The method for obtaining the diameter of the pipe according to claim 3, wherein the conversion coefficient E2 is determined by the following formula:

E2＝E/D*D2

wherein E is a calibration conversion coefficient, D2 is the distance from the laser head to the end face of the second pipe, and D is a calibration distance.

5. The method of claim 4, wherein the actual diameter of the second pipe is determined by the following equation:

R2＝I2/E2

where I2 is the diameter of the end face of the second tube in the image and E2 is the transformation factor of the second tube.

6. The method of claim 3, further comprising:

judging whether the actual diameter of the second pipe is the same as the preset diameter or in a set error range;

and if the first pipe material is different or exceeds the set error range, judging that the quality of the second pipe material is not qualified.

Technical Field

The invention belongs to the field of pipe measurement, and particularly relates to a pipe measurement calibration method.

Background

With the development of science and technology, the assembly line is widely applied to product production, particularly to plastic pipe production, wherein an extruder is used for completing initial injection molding of plastic pipes, and plastic particles form the plastic pipes through an extrusion process. However, the plastic pipe is affected by temperature, traction speed and extrusion speed in the extrusion process, and the wall thickness of the pipe is uneven, so that the diameter of the pipe becomes an important judgment basis for the quality of the pipe.

The inventor finds in practice that no method or device for detecting the diameter of the pipe has been presented on the market so far, which could lead to the outflow of defective products.

Disclosure of Invention

The invention aims to provide a pipe measurement calibration method, which can obtain a calibration conversion coefficient so as to finish the calibration of pipe measurement.

The invention also aims to provide a method for acquiring the diameter of the pipe according to the pipe measurement calibration method, which can automatically acquire the diameter of the pipe.

The embodiment of the invention provides a pipe measurement calibration method, which comprises the following steps: acquiring an image of the end face of the first pipe when the first pipe passes through the photoelectric switch; the image of the end face of the first pipe is shot by a camera;

acquiring the distance from a laser head to the end face of a first pipe when the first pipe passes through a photoelectric switch; the distance from the laser head to the end face of the first pipe is a calibration distance D; the distance D from the laser head to the end face of the first pipe is measured by a laser distance meter;

calculating to obtain the diameter I in the image of the end face of the first pipe according to an image processing algorithm;

and calculating to obtain a calibration conversion coefficient E of the pipe according to the actual diameter of the first pipe and the diameter I in the image of the end face of the first pipe.

Further, the conversion coefficient E is determined by the following formula:

E＝I/R

wherein E is a calibration conversion coefficient, I is the diameter of the end face of the first pipe in the image, and R is the actual diameter of the first pipe.

Compared with the related art, the embodiment of the invention can obtain the calibration conversion coefficient, thereby completing the calibration of the pipe measurement, and further facilitating the future upgrading to the automatic acquisition of the diameter of the pipe.

The embodiment of the invention also provides a method for obtaining the diameter of the pipe according to the pipe measurement calibration method, which comprises the following steps:

acquiring an image of the end face of the second pipe when the second pipe passes through the photoelectric switch;

obtaining the distance D2 between the laser head and the end face of the second pipe when the second pipe passes through the photoelectric switch;

calculating the diameter I2 of the image of the end face of the second pipe according to an image processing algorithm;

calculating to obtain a conversion coefficient E2 according to the calibration conversion coefficient E, the calibration distance D and the distance D2 from the laser head to the end face of the second pipe;

and calculating the actual diameter of the second pipe according to the diameter I2 of the image of the end face of the second pipe and a conversion coefficient E2.

Further, the conversion coefficient E2 is determined by the following formula:

E2＝E/D*D2

wherein E is a calibration conversion coefficient, D2 is the distance from the laser head to the end face of the second pipe, and D is a calibration distance.

Further, the actual diameter of the second tubing is determined by the following equation:

R2＝I2/E2

where I2 is the diameter of the end face of the second tube in the image and E2 is the transformation factor of the second tube.

Further, the method for obtaining the diameter of the pipe further comprises the following steps:

judging whether the actual diameter of the second pipe is the same as the preset diameter or in a set error range;

and if the first pipe material is different or exceeds the set error range, judging that the quality of the second pipe material is not qualified.

Compared with the related art, the embodiment of the invention can replace manual work to obtain the diameter of the pipe, and the actual size of the diameter of the pipe can be known when the pipe is produced, so that the diameter of the pipe can be known to meet the actual requirement.

Drawings

FIG. 1 is a flow chart of a method for calibrating a pipe measurement according to an embodiment of the present invention;

FIG. 2 is a flow chart of a method for obtaining a diameter of a pipe according to a pipe measurement calibration method provided by an embodiment of the invention;

FIG. 3 is a flow chart of a method for obtaining a pipe diameter according to a pipe measurement calibration method according to another preferred embodiment of the present invention.

Detailed Description

Referring to fig. 1, an embodiment of the present invention provides a pipe measurement calibration method, including:

s100, acquiring an image of the end face of the first pipe when the first pipe passes through the photoelectric switch; the image of the end face of the first pipe is shot by a camera;

s101, obtaining the distance from a laser head to the end face of a first pipe when the first pipe penetrates through a photoelectric switch; the distance from the laser head to the end face of the first pipe is a calibration distance D; the distance D from the laser head to the end face of the first pipe is measured by a laser distance meter;

s102, calculating according to an image processing algorithm to obtain the diameter I in the image of the end face of the first pipe;

s103, calculating to obtain a calibration conversion coefficient E of the pipe according to the actual diameter of the first pipe and the diameter I in the image of the end face of the first pipe.

Wherein the conversion coefficient E is determined by the following formula:

E＝I/R

wherein E is a calibration conversion coefficient, I is the diameter of the end face of the first pipe in the image, and R is the actual diameter of the first pipe.

In embodiments of the present invention, it is understood that the diameter of the first tube end face is the diameter of the first tube.

The embodiment of the invention can obtain the calibration conversion coefficient, thereby completing the calibration of the pipe measurement, and further facilitating the future upgrading to automatically acquiring the diameter of the pipe.

The embodiment of the invention provides a method for obtaining the diameter of the pipe according to the pipe measurement calibration method on the basis of the embodiment, which comprises the following steps:

s201, acquiring an image of the end face of the second pipe when the second pipe passes through the photoelectric switch;

s202, obtaining the distance D2 from the laser head to the end face of the second pipe when the second pipe passes through the photoelectric switch;

s203, calculating the diameter I2 of the image of the end face of the second pipe according to an image processing algorithm;

s204, calculating according to the calibration conversion coefficient E, the calibration distance D and the distance D2 from the laser head to the end face of the second pipe to obtain a conversion coefficient E2;

s205, calculating the actual diameter of the second pipe according to the diameter I2 of the image of the end face of the second pipe and a conversion coefficient E2.

Wherein the conversion coefficient E2 is determined by the following formula:

E2＝E/D*D2

wherein E is a calibration conversion coefficient, D2 is the distance from the laser head to the end face of the second pipe, and D is a calibration distance.

The actual diameter of the second tubing is determined by the following equation:

R2＝I2/E2

where I2 is the diameter of the end face of the second tube in the image and E2 is the transformation factor of the second tube.

In embodiments of the present invention, it is understood that the diameter of the second tubing end face is the diameter of the second tubing.

The embodiment of the invention can replace manual work to obtain the diameter of the pipe, and the actual size of the diameter of the pipe can be known when the pipe is produced, so that the diameter of the pipe can be known to meet the actual requirement.

In one preferred embodiment, the method for obtaining the diameter of the pipe further comprises:

s206, judging whether the actual diameter of the second pipe is the same as the preset diameter or in a set error range;

and S207, if the second pipe is different or exceeds a set error range, judging that the quality of the second pipe is not qualified.

According to the embodiment of the invention, whether the quality of the pipe is qualified or not can be judged according to the preset rule, so that the unqualified products can be reduced from being released to the market.

Referring to fig. 3, an embodiment of the present invention provides a pipe measurement calibration apparatus, which is used for obtaining necessary parameters of the calibration method and the pipe diameter method, and includes: the device comprises a pipe extrusion production line, a photoelectric switch, a camera light source, a camera and a laser range finder; the pipe extrusion production line is provided with a channel for carrying a pipe, the photoelectric switch is positioned on the pipe extrusion production line, the camera light source, the camera and the laser range finder are arranged at the tail end of the pipe extrusion production line, and the laser range finder is positioned below the camera; wherein the camera light source, the camera and the laser range finder are all aligned with the channel.

The laser range finder is arranged at a position 5cm below the camera and is aligned to the end face of the pipe under the condition of ensuring that the imaging of the camera is not influenced.

It will be appreciated that after extrusion the pipe is separated from the line to the rear end of the extrusion line by a length set according to the production requirements.

When necessary parameters of the calibration method and the method for acquiring the diameter of the pipe are acquired, the pipe is slowly moved to pass through a power-off switch, and then a camera triggers photographing imaging to acquire an image of the end face of the pipe; the laser distance measuring instrument is also triggered by the power-off switch, so that the distance D from the current laser head to the end face of the pipe is obtained.

In the embodiment of the invention, when the pipe passes through the photoelectric switch, the image of the end face of the pipe and the distance D from the laser head to the end face of the pipe can be automatically acquired, so that the diameter of the pipe can be automatically acquired by upgrading the method in the future.

In one preferred embodiment, the pipe measurement calibration apparatus further includes: an image processor.

The diameter R of the pipe just used is manually measured, and a conversion coefficient E between the diameter I in the image and the actual diameter R of the pipe is calculated by an image processing algorithm, wherein E is I/R.

After obtaining E and D, the production line calibration is completed, the production line can perform normal production after the calibration is completed, then each time when a pipe passes through the power-off switch, we can obtain the distance D2 from the current pipe to the end face of the pipe, the diameter I2 of the current pipe in the image, and the known value E, firstly, we calculate the conversion coefficient of the current position to be E2 according to E2\ D2 — E \ D, and since E2 is also equal to I2/R2, the diameter (size) of the current pipe can be directly obtained through R2 — I2/E2.

According to the embodiment of the invention, the calibration of pipe measurement can be completed, and the diameter of the pipe can be automatically obtained after the pipe calibration is completed.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the appended claims.