CN108335288A - The crater image method for detecting abnormality of view-based access control model clarity and contours extract - Google Patents

The crater image method for detecting abnormality of view-based access control model clarity and contours extract Download PDF

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Publication number
CN108335288A
CN108335288A CN201810047308.XA CN201810047308A CN108335288A CN 108335288 A CN108335288 A CN 108335288A CN 201810047308 A CN201810047308 A CN 201810047308A CN 108335288 A CN108335288 A CN 108335288A
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Prior art keywords
clarity
image
molten bath
profile
intermediate frequency
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韩静
徐林丽
张玉伟
赵壮
柏连发
张毅
王霄雯
张楚昊
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Nanjing University of Science and Technology
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Nanjing University of Science and Technology
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    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00Image analysis
    • G06T7/0002Inspection of images, e.g. flaw detection
    • G06T7/0004Industrial image inspection
    • G06T7/0006Industrial image inspection using a design-rule based approach
    • G06T5/73
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00Image analysis
    • G06T7/10Segmentation; Edge detection
    • G06T7/13Edge detection
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00Image analysis
    • G06T7/10Segmentation; Edge detection
    • G06T7/136Segmentation; Edge detection involving thresholding
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00Image analysis
    • G06T7/10Segmentation; Edge detection
    • G06T7/181Segmentation; Edge detection involving edge growing; involving edge linking
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00Indexing scheme for image analysis or image enhancement
    • G06T2207/10Image acquisition modality
    • G06T2207/10004Still image; Photographic image
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00Indexing scheme for image analysis or image enhancement
    • G06T2207/20Special algorithmic details
    • G06T2207/20024Filtering details
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00Indexing scheme for image analysis or image enhancement
    • G06T2207/30Subject of image; Context of image processing
    • G06T2207/30108Industrial image inspection
    • G06T2207/30152Solder

Abstract

The present invention proposes a kind of variation of the width of the value and profile according to vision definition to differentiate the detection method of the affiliated abnormal class of the crater image;The present invention is from image vision angle, in conjunction with clarity and the computation performance of contours extract, first with clarity operator just classify, is classified again to weldering speed in conjunction with profile width, reduce operation time to a certain extent.And the used double light path visual perception device of the present invention, it is effective to improve vision profile and clarity extraction accuracy.

Description

The crater image method for detecting abnormality of view-based access control model clarity and contours extract
Technical field
The invention belongs to molten bath visual fields, and in particular to the double light path vision sensing equipment and one kind of FPGA module triggering The crater image method for detecting abnormality that clarity and profile collaboration judge.
Background technology
Welding is important one of the processing technology of manufacturing industry, is widely used in material processing and structure manufacture. Skilled welder can be incorporated experience by observation weld pool surface information and prejudge and control to weldquality, with intelligence machine People's welding gradually replaces artificial weldering, and the accurate sensing of weld pool resonance is the important prerequisite of welding process intelligentized control method, needs to build Vertical reliable and stable visual sensing system ensures the crater image information obtained as far as possible comprehensively, accurately.
Molten bath two-dimensional visual sensing mainly carries out image sensing acquisition by vision-sensing method to molten bath, at image Reason and feature extraction analyze the relationship between characteristics of image and welding quality and establish Controlling model.With the continuous depth of research Enter, researcher the characteristics of molten bath in different materials, different welding methods in conjunction with rational visual sensing system is established, in molten bath figure As method for sensing, image processing algorithm, characteristics of image define and extracting method and the control of the welding quality of view-based access control model etc. Achieve greater advance.The accurate sensing of weld pool resonance is the important prerequisite of welding process intelligentized control method, needs to establish and stablize Reliable visual sensing system ensures the crater image information obtained as far as possible comprehensively, accurately.If directly utilizing visual sensing Device absorbs the crater image in welding process, and strong arclight will make the photosensitive primitive of CCD reach light saturation, and weld pool resonance is several It is fallen into oblivion completely by arclight.
To weaken the influence of arclight, this patent using molten bath vision and technological parameter collaborative perception device, for based on Clarity and the vision of contours extract calculate demand, are designed like scheme.Stronger boundary is needed due to calculating molten bath profile Contrast needs band logical height to expose;It calculates weld pool surface vision definition to need to inhibit arc light, needs the low exposure of high pass, therefore this Molten bath light beam is divided into the double light path vision sensing equipment of 850nm high passes and 650nm band logicals using Amici prism by patent.So may be used The weld pool surface information on the molten bath boundary for the high contrast that gets both and the interference of low arc light improves follow-up molten bath contours extract and clear Spend computational accuracy.After obtaining image, influenced to reduce various random noises and pattern distortion, this patent is stretched using intermediate frequency Method again pre-processes image, inhibits useless noise information, improves picture quality, is carried convenient for the calculating and profile of clarity It takes.
Invention content
The present invention is based on the crater image method for detecting abnormality of vision definition and contours extract, include the following steps:
Step 1:Determine the abnormal class that crater image is likely to occur;
Step 2:Design technology parameter collaborative perception FPGA module, according to different visions calculate demand, design specific aim at Image space case;
Step 3:The light path acquisition positive sample design step 2 and all kinds of negative samples;
Step 4:Intermediate frequency stretch processing is carried out to all crater image samples of acquisition and calculates its definition values, according to knot Fruit is distributed, and setting divides all kinds of threshold values organized extremely, determines current parameters exception, voltage parameter is abnormal and protection gas parameter is different Normal clarity range;
Step 5:It is special that normal group of the electrical parameter in step 4 acquired results in the case of consistent with protection gas parameter is subjected to profile The extraction of reference breath carries out data analysis to obtain the classification results of different weldering speed grades, realizes the inspection of molten bath weldering speed exception It surveys.
Further, demand is calculated according to different visions described in step 2, design specific aim is imaged scheme, specific mistake Cheng Wei:It such as calculates molten bath profile and needs stronger boundary contrast, the exposure of band logical height can be used;Calculate weld pool surface optical clarity Degree needs to inhibit arc light, and the low exposure of high pass can be used;Therefore molten bath light beam is divided into two bundles using Amici prism, a branch of use 850nm high passes, a branch of use 650nm band logicals, form double Spectral Visual sensing devices;And ensure that double spectrum samples synchronize.
Further, all crater image samples to acquisition described in step 4 carry out intermediate frequency stretch processing and calculate Its definition values, includes the following steps:
Step 3-1:The pretreatment of intermediate frequency stretching is carried out to the crater image that is obtained, is extracted more important thin in image Save component;
It is as follows that intermediate frequency component stretches formula:
In formula, H (x, y) is the image frequency domain after stretching, and D (x, y) is the frequency domain of original input image, dlIt is stretched for intermediate frequency Initial frequency, dhBe intermediate frequency stretch by frequency, m, n are the exponent number of filter;
Step 3-2:Optional step 3-1 clarity operator calculates the clarity of image;
Step 3-3:Classification results delimited manually, find definition values and play corresponding class relations;
The value for calculating separately above-mentioned clarity operator, manually sets the threshold value of all kinds of abnormal results, show that energy gradient is calculated The clarity evaluation operator result of the differentiation accuracy rate highest of son, energy gradient is as follows:
The image that image row direction is added with the difference of the gray value of neighbor pixel on column direction it is clear Clear angle value, in formula, I (x, y) is gray values of the image I at (x, y), and q (I) is the output result definition values of the function.
Further, positive sample and all kinds of negative samples are acquired under the conditions of double light path described in step 3, specifically include electricity Throat floater, electric voltage exception protect gas exception and weldering speed abnormal.
Further, described in step 5 by electrical parameter in step 4 acquired results with protection gas parameter it is consistent in the case of just Often group carry out contour feature information extraction the specific steps are:
Step 5-1:The ROI in molten bath is arranged;
First, big ROI is set and removes extra background area;Secondly, according to the overall permanence in molten bath, i.e., head brightness compared with High and be easy to be interfered by arc light, half resolidified region brightness of tail portion is relatively low and interferes less, can be classified as ROI1 and ROI2;Root According to the imaging characteristic on head and tail region, small scale gray scale stretching is carried out respectively, and gray scale stretching formula is as follows:
In formula, small scale is stretchedValue it is smaller can remove highlight regions, for large scale stretchValue it is larger, the contrast of tail portion entirety can be enhanced;
Step 5-2:The partitioning pretreatment in molten bath;
Gaussian filtering and opening operation are carried out to weaken the interference of edge arc light to the image that gray scale stretching in ROI1 is crossed, then Low threshold edge detection is carried out with Canny operators and filters out too small edge contour;Since the interference in the regions ROI2 is smaller, gray scale Distribution is relatively uniform, therefore directly carries out Da-Jin algorithm Threshold segmentation to the regions ROI2 and carry out high threshold with Canny operators Edge detection;
Step 5-3:Profile merges and connection;
ROI1 and the ROI2 edge contour detected are merged, and 8 neighborhoods and 16 neighborhoods of image are scanned for, The fracture of profile Small and Medium Sized is connected, the detection of profile endpoint is carried out for the fracture of large scale later, abutting end point is carried out Connection finally obtains the profile of molten bath connection.
Beneficial effects of the present invention are:This patent is from image vision angle, in conjunction with clarity and contours extract Computation performance first with clarity operator just classify, be classified again to weldering speed in conjunction with profile width, to a certain extent Reduce operation time.And the used double light path visual perception device of this patent, effective raising vision profile and clarity carry Take precision.
Description of the drawings
Fig. 1 is synchronous 850 high passes of present invention triggering, 650 band logical images;
Fig. 2 is the classification results of clarity of the present invention;
Fig. 3 is the extraction of molten bath profile of the present invention;
Fig. 4 is the classification of molten bath weldering speed of the present invention.
Specific implementation mode
Refering to fig. 1, steps are as follows for the specific implementation of 2,3,4 this patents:
Step 1, design technology parameter collaborative perception FPGA module builds double light path molten bath visual sensor acquisition molten bath figure Picture;
Step 2, frequency domain is transformed by Fourier transformation to 850 high-pass images acquired, carries out frequency domain details increasing By force, and using Fourier inversion by image time domain is gone back to from frequency domain again, obtains the result figure after intermediate frequency stretches;
Step 3, various clarity operators are selected to evaluate the image after stretching into line definition, and according to experiment sample institute Belong to classification to classify, finds and sort out the best clarity operator of effect;
Step 4, energy gradient operator classification effect is best in step 3, as shown in Fig. 2, energy gradient operator can be by Ar =0 group, too low group of electric current and brownout group these abnormal phenomenon are classified, and are divided according to threshold value is manually set, protection The definition values q of gas exception>5, current anomaly:q<0.6, low-voltage group:0.6<q<2, and electrical parameter and protection gas parameter it is normal Group:2<q<5.And the recognition accuracy of each part mentioned above is respectively to protect gas abnormal:90.0%;Current anomaly:98.44%; Electric voltage exception:91.33%, electrical parameter and protection gas parameter are normal:98.68%.Overall accuracy reaches:95.23%;
Step 5, when carrying out real-time abnormality detection with test image, if the value for clarity q occur is more than 5 or the feelings less than 2 Condition then suspends welding and checks corresponding exception, if definition values 2<q<5, then contours extract is carried out, and further detection is The counties Fou Chu weldering speed abnormal phenomenon;
Step 6, according to the characteristic information in obtained molten bath contours extract molten bath, such as:Pool width, molten bath length, molten bath Afterwards towing angle, molten bath length-width ratio.It can be divided by hard -threshold according to the width information extracted, distinguish same welding procedure And same welding electrical parameters, weldering speed grade under conditions of camera angle is constant.The higher pool width of weldering speed is smaller, molten bath Length is longer, otherwise the lower pool width of weldering speed is bigger, and molten bath length is smaller.By carrying out respectively obtaining difference to data The hard segmentation threshold of weldering speed grade, from th1 to th6.It is 2mm/s that its middle grade a pair, which answers weldering speed, grade and correspond to weldering speed and be 4mm/s, it is 6mm/s that grade three, which corresponds to weldering speed, and it is 8mm/s that grade four, which corresponds to weldering speed, and it is 12mm/s, grade that grade five, which corresponds to weldering speed, Six correspond to the 16mm/s of weldering speed, as shown in Figure 4.

Claims (5)

1. the crater image method for detecting abnormality of view-based access control model clarity and contours extract, which is characterized in that include the following steps:
Step 1:Determine the abnormal class that crater image is likely to occur;
Step 2:Design technology parameter collaborative perception FPGA module calculates demand, design specific aim imaging side according to different visions Case;
Step 3:The light path acquisition positive sample design step 2 and all kinds of negative samples;
Step 4:Intermediate frequency stretch processing is carried out to all crater image samples of acquisition and calculates its definition values, according to result point Cloth, setting divide all kinds of threshold values organized extremely, determine current parameters exception, voltage parameter is abnormal and protects gas abnormal parameters Clarity range;
Step 5:Normal group of the electrical parameter in step 4 acquired results in the case of consistent with protection gas parameter is subjected to contour feature letter The extraction of breath carries out data analysis to obtain the classification results of different weldering speed grades, realizes the detection of molten bath weldering speed exception.
2. molten bath vision according to claim 1 and technological parameter collaborative perception device, which is characterized in that described in step 2 Calculate demand according to different visions, design specific aim is imaged scheme, and detailed process is:It is stronger such as to calculate molten bath profile needs The exposure of band logical height can be used in boundary contrast;It calculates weld pool surface vision definition to need to inhibit arc light, the low exposure of high pass can be used Light;Therefore molten bath light beam is divided into two bundles using Amici prism, it is a branch of to use 850nm high passes, is a branch of using 650nm band logicals, shape Spectral Visual sensing device in pairs;And ensure that double spectrum samples synchronize.
3. the molten bath Outlier Detection Algorithm of view-based access control model clarity according to claim 1, which is characterized in that step 4 institute All crater image samples to acquisition stated carry out intermediate frequency stretch processing and calculate its definition values, include the following steps:
Step 3-1:The pretreatment that intermediate frequency stretching is carried out to the crater image obtained, extracts details more important in image point Amount;
It is as follows that intermediate frequency component stretches formula:
In formula, H (x, y) is the image frequency domain after stretching, and D (x, y) is the frequency domain of original input image, dlThe starting stretched for intermediate frequency Frequency, dhBe intermediate frequency stretch by frequency, m, n are the exponent number of filter;
Step 3-2:Optional step 3-1 clarity operator calculates the clarity of image;
Step 3-3:Classification results delimited manually, find definition values and play corresponding class relations;
The value for calculating separately above-mentioned clarity operator, manually sets the threshold value of all kinds of abnormal results, obtains energy gradient operator Differentiate that accuracy rate highest, the clarity evaluation operator result of energy gradient are as follows:
The clarity for the image that image row direction is added with the difference of the gray value of neighbor pixel on column direction It is worth, in formula, I (x, y) is gray values of the image I at (x, y), and q (I) is the output result definition values of the function.
4. the molten bath Outlier Detection Algorithm according to claim 1 based on clarity and contours extract, which is characterized in that Positive sample and all kinds of negative samples are acquired under the conditions of double light path described in step 3, specifically includes current anomaly, and electric voltage exception is protected It protects gas exception and weldering speed is abnormal.
5. the molten bath Outlier Detection Algorithm according to claim 1 based on clarity and contours extract, which is characterized in that Normal group of the electrical parameter in step 4 acquired results in the case of consistent with protection gas parameter is subjected to contour feature letter described in step 5 The extraction of breath the specific steps are:
Step 5-1:The ROI in molten bath is arranged;
First, big ROI is set and removes extra background area;Secondly, according to the overall permanence in molten bath, i.e., head brightness it is higher and It is easy to be interfered by arc light, half resolidified region brightness of tail portion is relatively low and interferes less, can be classified as ROI1 and ROI2;According to head The imaging characteristic in portion and tail region, carries out small scale gray scale stretching respectively, and gray scale stretching formula is as follows:
In formula, small scale is stretchedValue it is smaller can remove highlight regions, for large scale stretch's It is worth larger, the contrast of tail portion entirety can be enhanced;
Step 5-2:The partitioning pretreatment in molten bath;
Gaussian filtering and opening operation are carried out to weaken the interference of edge arc light to the image that gray scale stretching in ROI1 is crossed, then used Canny operators carry out Low threshold edge detection and filter out too small edge contour;Since the interference in the regions ROI2 is smaller, gray scale point Cloth is relatively uniform, therefore directly carries out Da-Jin algorithm Threshold segmentation to the regions ROI2 and carry out high threshold side with Canny operators Edge detects;
Step 5-3:Profile merges and connection;
ROI1 and the ROI2 edge contour detected are merged, and 8 neighborhoods and 16 neighborhoods of image are scanned for, is connected The fracture of profile Small and Medium Sized later carries out the fracture of large scale the detection of profile endpoint, abutting end point is attached, Finally obtain the profile of molten bath connection.
CN201810047308.XA 2018-01-18 2018-01-18 The crater image method for detecting abnormality of view-based access control model clarity and contours extract Withdrawn CN108335288A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111257348A (en) * 2020-03-27 2020-06-09 河海大学常州校区 LED light guide plate defect detection method based on machine vision
CN111932572A (en) * 2020-10-12 2020-11-13 南京知谱光电科技有限公司 Aluminum alloy molten pool contour extraction method
CN112756783A (en) * 2021-01-06 2021-05-07 广东工业大学 Method for determining welding keyhole offset in laser welding tracking process

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106112318A (en) * 2016-07-13 2016-11-16 桂林航天工业学院 The online welding seam tracking method of a kind of view-based access control model and system
CN107363403A (en) * 2017-09-09 2017-11-21 深圳市华天世纪激光科技有限公司 A kind of laser welding system based on CCD vision monitorings
CN108320280A (en) * 2018-01-16 2018-07-24 南京理工大学 The crater image method for detecting abnormality of view-based access control model clarity and contours extract

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106112318A (en) * 2016-07-13 2016-11-16 桂林航天工业学院 The online welding seam tracking method of a kind of view-based access control model and system
CN107363403A (en) * 2017-09-09 2017-11-21 深圳市华天世纪激光科技有限公司 A kind of laser welding system based on CCD vision monitorings
CN108320280A (en) * 2018-01-16 2018-07-24 南京理工大学 The crater image method for detecting abnormality of view-based access control model clarity and contours extract

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111257348A (en) * 2020-03-27 2020-06-09 河海大学常州校区 LED light guide plate defect detection method based on machine vision
CN111932572A (en) * 2020-10-12 2020-11-13 南京知谱光电科技有限公司 Aluminum alloy molten pool contour extraction method
CN112756783A (en) * 2021-01-06 2021-05-07 广东工业大学 Method for determining welding keyhole offset in laser welding tracking process

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