CN104567714A - Portable non-contact roundness measurement instrument - Google Patents

Abstract

The invention provides a portable non-contact roundness measurement instrument. According to the portable non-contact roundness measurement instrument, an end surface image of a tested steel tube is collected by a CCD (charge coupled device), and the roundness is tested with a DSP (digital signal processor) image processing algorithm. The instrument has lower cost, is simple and convenient to operate and is suitable for non-contact field high-precision roundness measurement.

Description

Portable noncontact roundness measuring instrument

Technical field:

The present invention relates to a kind of noncontact roundness measuring device, specifically a kind of portable noncontact roundness measuring instrument.

Background technology:

In steel pipe's production and use procedure, need to carry out roundness measurement.Current most of factory adopts slide calliper rule manual measurement, is difficult to maximal value and the minimum value of finding diameter accurately.Patent 201120256720.6 discloses a kind of roundness measurement instrument of steel pipe, surveys steel pipe displacement with worktable rotating grating chi, and the method needs to rotate one week around steel pipe mechanical, and Long-Time Service can effect of attrition measuring accuracy.Patent 201120049924.2 discloses a kind of UOE pipe end ovality and diameter measuring device, and this device adopts leading screw driving laser displacement sensor steel pipe circular section, because mechanical scanning motion can cause measuring error.

Summary of the invention:

The object of the invention is to provide a kind of portable noncontact roundness measuring instrument for the deficiencies in the prior art.This instrument adopts CCD and monolithic DSP microprocessor to carry out non-cpntact measurement, and measuring accuracy is high, easy and simple to handle, is easy to carry.

Technical scheme of the present invention:

A kind of portable noncontact roundness measuring instrument, on its housing laser tube is housed, side is embedded with liquid crystal display, opposite side fixation of C CD, enclosure has DSP image processor, and laser incides on tested Steel pipe end surface and forms luminous point, and DSP image processor calculates tested steel pipe roundness size.

Laser tube sends many distributing line laser, and incide end face and form luminous point, CCD gathers tested steel pipe dot pattern picture, and DSP image processor processes image, calculates the circularity of tested steel pipe.

DSP image processor can adopt TMS320DM642 chip, utilizes grey scale centre of gravity algorithm to calculate spot center coordinate, then calculates circularity size.

The measurement result of this instrument is also transferred in data-carrier store or database by wired or wireless mode.

The invention has the beneficial effects as follows: compared with the prior art, the present invention is a kind of portable non-contact measuring device based on CCD and DSP, adopts common image processing program, and algorithm is simple, and measuring accuracy is high, easy and simple to handle, easy to carry, and cost is very limited.

Accompanying drawing illustrates:

Fig. 1 is structural representation of the present invention.

Mark in figure: 1 laser tube, 2CCD, 3DSP image processor, 4 liquid crystal displays, 5 shells, 6 tested steel pipes.

Embodiment:

As shown in Figure 1, portable noncontact roundness measuring instrument.Comprise 1 laser tube, 2CCD, 3DSP image processor,

4 liquid crystal displays, 5 shells, 6 tested steel pipes.

Described laser tube 1 sends many distributing line laser, is fixed on shell 5.

Described DSP image processor 3 can adopt the DSP embedded based on TMS320DM642 chip, and measurement result is presented on small size liquid crystal display 4, is convenient to measurement mechanism instrumentation.Measurement result is also transferred in data-carrier store or database by the serial communication interface of DSP in a wired or wireless fashion, can be recorded in U disk file as connect serial ports USB module, connecing serial ports SD module can be recorded in SD card file, connect serial ports wireless module can with server database wireless connections, also can be connected on the net by the network interface of DSP.

Laser tube 1 sends the light of 650nm wavelength, incides on tested Steel pipe end surface and forms luminous point, and CCD2 gathers dot pattern picture, and DSP image processor 3 calculates tested steel pipe 6 circularity size.Measuring principle is as follows:

As shown in Figure 1, the position calculation of luminous point on image adopts grey scale centre of gravity formula:

$x_c=\frac{{\mathrm{\Σ}}_{i_0}^{i_f}{\mathrm{\Σ}}_{j_0}^{j_f}j(T-f_{\mathrm{ij}})}{{\mathrm{\Σ}}_{i_0}^{i_f}{\mathrm{\Σ}}_{j_0}^{j_f}(T-f_{\mathrm{ij}})}$

$y_c=\frac{{\mathrm{\Σ}}_{i_0}^{i_f}{\mathrm{\Σ}}_{j_0}^{j_f}i(T-f_{\mathrm{ij}})}{{\mathrm{\Σ}}_{i_0}^{i_f}{\mathrm{\Σ}}_{j_0}^{j_f}(T-f_{\mathrm{ij}})}$

In formula T be dot pattern as gray threshold, f is the gray-scale value of each pixel, x and y is luminous point gray scale centre coordinate.

Steel pipe roundness is calculated through curve by fixed each luminous point coordinate.

Grey scale centre of gravity arithmetic accuracy is 0.02 pixel, and as corresponding 0.1 millimeter of pixel every in image processing system, this device luminous point co-ordinate measurement accuracy is 0.002 millimeter.

Claims (3)

1. a portable noncontact roundness measuring instrument, it is characterized in that: shell (5) is equipped with laser tube (1), side is embedded with liquid crystal display (4), opposite side fixation of C CD(2), there is DSP image processor (3) shell (5) inside, laser incides on tested steel pipe (6) end face and forms luminous point, and DSP image processor (3) calculates tested steel pipe (6) circularity size.

2. the portable noncontact roundness measuring instrument of one according to claim 1, is characterized in that: measurement result is also transferred in data-carrier store or database by wired or wireless mode.

3. the portable noncontact roundness measuring instrument of one according to claim 1, is characterized in that: laser tube sends many distributing line laser, incides end face and forms luminous point.