CN102914479A - Automatic Brinell hardness testing method - Google Patents
Automatic Brinell hardness testing method Download PDFInfo
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- CN102914479A CN102914479A CN2012102892184A CN201210289218A CN102914479A CN 102914479 A CN102914479 A CN 102914479A CN 2012102892184 A CN2012102892184 A CN 2012102892184A CN 201210289218 A CN201210289218 A CN 201210289218A CN 102914479 A CN102914479 A CN 102914479A
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- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000007542 hardness measurement Methods 0.000 title abstract description 3
- 238000012360 testing method Methods 0.000 claims abstract description 32
- 238000007373 indentation Methods 0.000 claims abstract description 25
- 238000004364 calculation method Methods 0.000 claims description 4
- 238000005070 sampling Methods 0.000 claims description 4
- 230000014759 maintenance of location Effects 0.000 claims description 2
- 238000009304 pastoral farming Methods 0.000 claims description 2
- 238000001514 detection method Methods 0.000 abstract description 5
- 238000005516 engineering process Methods 0.000 abstract description 4
- 238000005259 measurement Methods 0.000 abstract description 3
- 230000007547 defect Effects 0.000 abstract 1
- 230000003287 optical effect Effects 0.000 abstract 1
- 230000003746 surface roughness Effects 0.000 description 4
- 238000003556 assay Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010191 image analysis Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 230000035772 mutation Effects 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
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Abstract
本发明的优点包括：1.利用计算机图像识别代替了人工检测法，可快速、准确地测定布氏硬度，克服了现有技术中需人工干预、主观性强、检测精度低、对待测试件表面质量要求高等缺陷；2.采用内部光学系统获取压痕图像，具有成本低、图像质量高和便于携带操作的优点；3.利用图像处理技术科学地描述压痕形状特征，能够客观地反映压痕边缘的细微变化，并利用压痕边缘曲率变化，剔除由表面质量差造成的噪声边缘，提高了硬度测定的精确度；4.根据本发明的方法编制的计算机图像测定系统，具有好的扩展能力，对各类试件表面质量的适应度高，具有自动化程度高、操作快速、简便的特点。
The advantages of the present invention include: 1. Using computer image recognition to replace the manual detection method can quickly and accurately measure the Brinell hardness, which overcomes the need for manual intervention in the prior art, strong subjectivity, low detection accuracy, and the surface of the test piece. Defects with high quality requirements; 2. The internal optical system is used to obtain the indentation image, which has the advantages of low cost, high image quality and easy to carry operation; 3. The use of image processing technology to scientifically describe the shape characteristics of the indentation can objectively reflect the indentation The subtle changes of the edge, and the use of the indentation edge curvature change, eliminates the noise edge caused by the poor surface quality, and improves the accuracy of hardness measurement; 4. The computer image measurement system compiled according to the method of the present invention has good expansion ability , has high adaptability to the surface quality of various test pieces, and has the characteristics of high degree of automation, fast and simple operation.
Description
Technical field
The present invention relates to a kind of Brinell hardness automatic measuring method, belong to the computer image processing technology field.A kind of method of utilizing image processing techniques to carry out the Brinell hardness quick automatic determining specifically.
Background technology
The ultimate principle that Brinell hardness is measured: a standard hardness spherical indenter is imposed certain pressure, is pressed into the testee surface, shed load after testee with a residual circular impression, determine the hardness number of material according to the size of impression.The size of hardness number press head diameter, load and impression diameter is calculated according to formula and is got.Wherein, impression diameter is used microscope artificial observation reading usually, or after using digital camera to obtain indentation image, manually chooses the impression frontier point and calculate impression diameter.They mainly depend on eye-observation, require the tester to possess certain working experience and professional skill, determination efficiency is lower, and cause easily personal error, and the result who causes the different operating and measure between the person is different.
At present, Brinell hardness impression diameter quick automatic determining method is being sought in this area.A kind of scheme is to utilize the CCD camera to obtain indentation image, utilization image processing techniques realization automatically accurately measuring the impression size.But because measured test specimen surface texturisation is different, institute gathers and often has more noise contribution in the indentation image, has reduced the degree of accuracy of accuracy and the specimen hardness measurement of indentation edge extraction.
In order to guarantee the accurate measurement of impression diameter, require the test specimen surface to answer flat-satin in the national standard (GB/T231.1-2009), and do not have oxide skin and extraneous dirt etc., and recommendation form surface roughness parameter Ra is not more than 1.6 μ m.Therefore, need by mechanical means (upper grinding machine) or manual method measured surface to be carried out cutting down, make the measured surface roughness of sample reach inspection side slat spare.The surface roughness value is lower after the finishing, and when gathering indentation image, its image quality is better, indentation image edge clear (such as Fig. 2).But effects on surface carries out cutting down, has both consisted of additional operation link, also makes to measure the cost rising.
Summary of the invention
In order more accurately to measure material hardness, the invention provides a kind of scheme, wherein, utilize computer image processing technology, in conjunction with the impression shape facility, obtain quickly and accurately the shape information of impression, scientifically describe the slight change of impression shape, thereby the testing staff is freed from the heavy duplication of labour.
The variety of issue that exists in order to overcome present detection method the object of the present invention is to provide a kind of machine vision technique that utilizes to realize fast, accurately assay method of Brinell hardness.In the present invention, at first utilize image processing techniques to extract indentation edge, extracted the impression shape facility, then by describing the slight change of impression shape, reject pseudo-edge, keep the impression true edge, final by calculating the impression diameter size, realize the Accurate Measurement of Brinell hardness.
According to an aspect of the present invention, provide a kind of Brinell hardness automatic measuring method, it is characterized in that comprising:
Gather the image of the impression on the test specimen;
Extract the edge of the described image of described impression;
Reject the pseudo-edge in the described edge;
Generation impression circle;
The hardness of calculation testing piece.
Description of drawings
Fig. 1 is Image Acquisition according to an embodiment of the invention and treating apparatus connection diagram;
Fig. 2 has shown the image through a smooth surface impression behind the cutting down;
Fig. 3 is indentation image and edge extracting after the general industry polishing according to an embodiment of the invention;
Fig. 4 is rust face indentation image according to an embodiment of the invention and edge extracting.
Embodiment
According to one embodiment of present invention, provide a kind of Brinell hardness automatic method for measuring, it has fast, accurately, stable, need not the advantage such as manual intervention fully, to overcome the deficiencies in the prior art.
To achieve these goals, Brinell hardness automatic measuring method according to an embodiment of the invention comprises:
-collection test specimen indentation image
Use sclerometer that the sintered carbide ball of certain diameter is applied test force Specimen surface, after the regulation retention time, the removal test force, impression appears in the test specimen surface.As shown in Figure 1, (portable) Brinell hardness analyzer 1 vertically is positioned over the surface of test specimen 2, gathers indentation image information on the test specimen surface with portable Brinell hardness analyzer 1, and input computing machine 3.
-extraction indentation edge
Common industrial sanding apparatus is processed test surfaces, and the surface roughness value is higher, and the indentation image marginal portion is fuzzy such as Fig. 3 (a) and Fig. 4 (a).And through after the image analysis processing, obtain corresponding indentation edge shown in Fig. 3 (b) and Fig. 4 (b).
The pseudo-edge of-rejecting impression
Because the test specimen surface quality is not high, causes the indentation edge noise spot more, has the part pseudo-edge, does not namely belong to the edge of true impression.After needing to reject pseudo-edge, justify match with true edge.
, the indentation edge each point is asked for curvature, and asks the curvature changing value so that rounded edge produces the characteristics of sudden change for noise spot, the reacting condition of curvature the situation of change of outline line, the curvature of circle contour changes comparatively smooth, changing value is less than predetermined value (such as 0.3).And there is part in noise spot, has the curvature mutation phenomenon.Therefore, in according to one embodiment of present invention, judge and the rejecting pseudo-edge by following steps:
A. the point (such as upper left point) on the impression profile (as counterclockwise), is followed the tracks of the impression profile as starting point in a direction, carries out the sampling of interval predetermined number (such as 10) pixel,
B. calculate the curvature k of certain some p of impression profile.Computation process is as follows:
k=θ
2-θ
1
Wherein, (x
p, y
p) be the coordinate of some p; Upper left as starting point with outline line, by counterclockwise outline line being followed the tracks of, interval i (such as i=10) pixel obtains two neighbouring sample point (x of current point
P-i,y
P-i), (x
P+i, y
P+i); θ
j(j=1,2) are the grazing angle of corresponding sampled point;
C. add up the curvature changing value continuously less than the sampled point of predetermined changing value (such as 0.3),
D. judge whether accumulative total surpasses a predetermined accumulative total numerical value (such as 10), belongs to arc section if "Yes" is then judged related pixel, belongs to pseudo-edge if "No" is then judged related pixel.
E. reject pseudo-edge.
-generation impression circle
After rejecting pseudo-edge, keep one section or multi-section circular arc on the impression profile, arc section is carried out match, thereby obtain the impression fitting circle, such as Fig. 3 .c and Fig. 4 .c.
-calculating test specimen hardness
Can calculate the hardness of test specimen according to impression match diameter of a circle and correlation parameter, computing method as shown in Equation (1).
According to the actual result of the Brinell hardness assay method of this embodiment, the hardness number precision reaches 0.01HBW, and impression diameter is to 0.0001mm resolution, and measures impression and show that the result only needs less than 1 second.
Advantage of the present invention comprises:
1. utilize computer picture recognition to replace the manual detection method, can measure Brinell hardness quick, objective, exactly, overcome in the prior art scheme need manual intervention, subjectivity is strong, accuracy of detection is low, treat the test block surface quality requires high defective;
2. the present invention adopts internal optics system acquisition indentation image, has that cost is low, picture quality is high and the advantage such as the operation that is easy to carry;
3. utilize image processing techniques scientifically to describe the impression shape facility, can reflect objectively the slight change of indentation edge, and utilize indentation edge curvature to change, reject by the poor noise edge that causes of surface quality, finally improve the degree of accuracy of Determination of Hardness;
4. measure system according to the computer picture of the method for the invention establishment, also have preferably extended capability.Fitness to all kinds of test specimen surface quality is high, has automaticity height, quick, the easy characteristics of operation.
Claims (10)
1. Brinell hardness automatic measuring method is characterized in that comprising:
Gather the image of the impression on the test specimen (2);
Extract the edge of the described image of described impression;
Reject the pseudo-edge in the described edge;
Generation impression circle;
The hardness of calculation testing piece (2).
2. according to claim 1 method, the step that it is characterized in that gathering the image of the impression on the test specimen (2) comprises:
Brinell hardness analyzer (1) is vertically placed the surface of test specimen (2),
With the lip-deep indentation image information of Brinell hardness analyzer (1) collection test specimen (2), and with indentation image input information computing machine (3).
3. according to claim 2 method, the step at edge that it is characterized in that extracting the described image of described impression comprises:
Industrial grinding process is carried out on surface to test specimen (2).
4. according to claim 3 method is characterized in that the step of rejecting the pseudo-edge in the described edge comprises:
A. a point on the impression profile is followed the tracks of the impression profile as starting point in a direction, carries out the sampling of the pixel of interval predetermined number;
B. calculate the curvature of the sampling pixel points of impression profile;
C. add up the curvature changing value continuously less than the sampled point of predetermined curvature changing value;
D. judge whether accumulative total surpasses a predetermined accumulative total numerical value, belongs to arc section if "Yes" is then judged related pixel, belongs to pseudo-edge if "No" is then judged related pixel;
E. reject pseudo-edge.
5. according to claim 4 method is characterized in that the step of described generation impression circle comprises:
The arc section of rejecting the impression profile that keeps behind the pseudo-edge carries out match, thereby obtains the impression fitting circle.
6. according to claim 5 method is characterized in that the step of calculation testing piece (2) hardness comprises:
According to the load value of described impression match diameter of a circle and input, calculate the hardness of test specimen.
7. according to claim 4 method is characterized in that:
Described predetermined curvature changing value is 0.3,
Described predetermined accumulative total numerical value is 10.
8. method one of according to claim 1-7 is characterized in that further comprising:
Apply test force by the sintered carbide ball to certain diameter and described sintered carbide ball is pressed into the surface of described test specimen (2) with sclerometer, and after the retention time that keeps being scheduled to,
The removal test force,
Thereby the surface at test specimen (2) forms described impression.
9. according to claim 8 method is characterized in that:
Described Brinell hardness analyzer (1) is portable Brinell hardness analyzer.
10. according to claim 6 method is characterized in that:
The step of the curvature of the sampling pixel points of described calculating impression profile comprises;
Get
k=θ
2-θ
1
Wherein, k is described curvature, (x
p, y
p) be the coordinate of some p; Upper left as starting point with outline line, by counterclockwise outline line being followed the tracks of, an i pixel in interval obtains two neighbouring sample point (x of current point
P-i, y
P-i), (x
P+i, y
P+i); θ
j(j=1,2) are the grazing angle of corresponding sampled point;
The step that described load value according to described impression match diameter of a circle and input calculates the hardness of test specimen is undertaken by following formula:
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| CN2012102892184A CN102914479A (en) | 2012-08-14 | 2012-08-14 | Automatic Brinell hardness testing method |
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| CN2012102892184A CN102914479A (en) | 2012-08-14 | 2012-08-14 | Automatic Brinell hardness testing method |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103364293A (en) * | 2013-07-19 | 2013-10-23 | 徐州豪立电子有限公司 | Portable material Brinell hardness measurement instrument and control method thereof |
| CN104964890A (en) * | 2015-05-14 | 2015-10-07 | 东莞市中旺精密仪器有限公司 | One-piece terminal application-based hardness detection method |
| CN107796718A (en) * | 2017-10-13 | 2018-03-13 | 郑显锋 | Brineling system and method |
| CN112014252A (en) * | 2020-09-02 | 2020-12-01 | 徐州工程学院 | Brinell hardness field measuring device for small-diameter pipe |
| CN112945704A (en) * | 2021-03-16 | 2021-06-11 | 八都机械锻造(苏州)有限公司 | Brinell hardness online detection system for intelligent factory |
| CN113052787A (en) * | 2019-12-27 | 2021-06-29 | 中核北方核燃料元件有限公司 | Automatic identification device and method for riser of ball blank |
Citations (1)
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| CN101377457A (en) * | 2007-08-30 | 2009-03-04 | 上海电气集团上海电机厂有限公司 | Method for measuring brinell hardness |
-
2012
- 2012-08-14 CN CN2012102892184A patent/CN102914479A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101377457A (en) * | 2007-08-30 | 2009-03-04 | 上海电气集团上海电机厂有限公司 | Method for measuring brinell hardness |
Non-Patent Citations (2)
| Title |
|---|
| 敖勤等: "布氏硬度图像自动测量及其Matlab实现", 《北京信息科技大学学报》 * |
| 荀一等: "基于轮廓曲率的树上苹果自动识别", 《江苏大学学报(自然科学版)》 * |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103364293A (en) * | 2013-07-19 | 2013-10-23 | 徐州豪立电子有限公司 | Portable material Brinell hardness measurement instrument and control method thereof |
| CN104964890A (en) * | 2015-05-14 | 2015-10-07 | 东莞市中旺精密仪器有限公司 | One-piece terminal application-based hardness detection method |
| CN104964890B (en) * | 2015-05-14 | 2018-06-05 | 东莞市中旺精密仪器有限公司 | Hardness detection method based on integral type terminal applies |
| CN107796718A (en) * | 2017-10-13 | 2018-03-13 | 郑显锋 | Brineling system and method |
| CN113052787A (en) * | 2019-12-27 | 2021-06-29 | 中核北方核燃料元件有限公司 | Automatic identification device and method for riser of ball blank |
| CN112014252A (en) * | 2020-09-02 | 2020-12-01 | 徐州工程学院 | Brinell hardness field measuring device for small-diameter pipe |
| CN112014252B (en) * | 2020-09-02 | 2023-03-14 | 徐州工程学院 | Brinell hardness field measuring device for small-diameter pipe |
| CN112945704A (en) * | 2021-03-16 | 2021-06-11 | 八都机械锻造(苏州)有限公司 | Brinell hardness online detection system for intelligent factory |
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Application publication date: 20130206 |