CN103615987A - Method for measuring distance between central electrode and ground electrode of spark plug based on edge sub-pixel technology - Google Patents
Method for measuring distance between central electrode and ground electrode of spark plug based on edge sub-pixel technology Download PDFInfo
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- CN103615987A CN103615987A CN201310682738.6A CN201310682738A CN103615987A CN 103615987 A CN103615987 A CN 103615987A CN 201310682738 A CN201310682738 A CN 201310682738A CN 103615987 A CN103615987 A CN 103615987A
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Abstract
The invention belongs to the measuring filed of precise instruments and specifically discloses a method for measuring distance between a central electrode and a ground electrode of a spark plug based on an edge sub-pixel technology. The method comprises the following steps of determining the position of the spark plug by adopting an integer pixel edge extracting technology and an edge sub-pixel positioning technology; then, calibrating a region of interest for measuring according to a matching posture; and finally, measuring clearance size of the spark plug by an grey outline of the spark plug obtained by adopting one-dimension extraction. The method disclosed by the invention can be applied to measuring field of precise components.
Description
Technical field
The invention belongs to exact instrument fields of measurement, relate to the distance measurement method between a kind of central electrode and ground electrode.Be particularly related to a kind of position that adopts edge sub-pixel technology to determine spark plug, realize the measurement of spark plug gap size.
Background technology
Modern spark plug applications is more and more extensive, and it is mainly used on the engines such as automobile, motorcycle.The size of spark clearance value has impact to a certain degree to the serviceability of engine.If electrode gap value is too little, the arcing time early and electric spark too little, make the burning of combination gas perfect not.If electrode gap value is too large, the arcing time more late and the electric spark duration is too short, even without electric spark, produce, a little less than lacking fire or spark while causing high engine speeds running, be unfavorable for the performance of high engine speeds, acceleration.So the distance between central electrode and side or ground electrode must in certain scope, guarantee spark plug can be for specific engine type.
Edge sub-pixel technology
Therefore, adopt edge sub-pixel technology, design the distance measurement method between a kind of central electrode and ground electrode, can improve the range measurement accuracy between central electrode and ground electrode, and the measurement of the precision apparatus of other applications is had and well instructs reference, there is certain using value.
Summary of the invention
Technical matters to be solved by this invention is, designs a kind of central electrode based on edge sub-pixel technology and the distance measurement method between ground electrode, is particularly useful for the requirement of the range observation accuracy between central electrode and ground electrode.
The technical solution adopted in the present invention is: adopt whole pixel edge extractive technique and edge sub-pixel location technology to determine the position of spark plug.Then according to the attitude of coupling, to calibrating for the area-of-interest of measuring; Finally adopt one dimension edge extracting to obtain its gray level skeleton to complete the measurement to spark plug gap size.The present invention can be applicable in the fields of measurement of precision component.
The object of the invention is to adopt edge sub-pixel technology to realize the range observation between central electrode and ground electrode, and can complete the functions such as data management statistics.
Accompanying drawing explanation
Accompanying drawing 1 is: battery surface curve Wave Decomposition figure
Accompanying drawing 2 is: battery surface defect
Embodiment
Below in conjunction with accompanying drawing, the present invention is described in further detail.
Detailed process is as follows:
1, spark plug image registration
Due to the impact of noise in each sensor imaging process, the position of target in different images there are differences, as translation, rotation, ratio variation etc.In problem, adopt affined transformation to realize the conversion of image, utilize boundary-related computing to set up affine Transform Model, self-adaptation is tried to achieve the registration parameter of image, automatically realizes translation, the Rotation and Zoom of image.
First to needing the initial value of two width Image estimation registrations of registration, set up the coordinate corresponding relation of two point sets.Calculate two image boundary cross-correlation matrixs, find out maximal correlation horizontal level and upright position.An approximate range can be first determined in choosing of the comparative example factor and the anglec of rotation, then sets certain interval and makes step factor, is principle to the maximum carries out iterative search with cross-correlation coefficient, and self-adaptation obtains optimum value.Obtained after optimal scale factors and the anglec of rotation, then original horizontal position and upright position have been searched for by pixel along two orthogonal directionss of image by maximal correlation principle, to obtain optimum level position and upright position.Determined after registration parameter, just can carry out translation, Rotation and Zoom to visible images.
2, determine spark-plug location
Adopt least-squares linear regression linear edge sub-pixel positioning method to determine spark-plug location.In spark plug range observation, object edge is seen as to desirable straight line.First adopt Gauss's Laplace function (Laplacian of Gaus-sian), also be LOG operator, carry out convolution algorithm with original image, by trying to achieve zero cross point, obtain whole pixel edge point, image border is navigated to whole Pixel-level precision, and then edge point directly carries out least-squares linear regression and obtains sub-pixel edge location.Take 100 point estimation least-squares linear regression to estimate straight line coefficient.
In online testing process, use shape on image, to look for spark plug:
Spark plug pose according to finding, creates measuring rectangle.Because the direction of spark plug in all images is roughly the same, during model creation, only consider ± 30 ° of scopes.
First the pose of coupling is carried out to two-dimensional rigid conversion, model is overlapped with the spark plug in image.Then, the relative position that utilizes the transfer pair obtaining to measure rectangular centre converts, and finally makes the direction of rectangle and the direction of spark plug consistent.
By calculating the local extremum of gray-scale value profile first order derivative, obtain one dimension border.
3, spark plug gap is determined
The size of spark plug gap is namely by the distance between the parallel lines of two marginal points.
The invention has the advantages that, adopt edge sub-pixel technology to determine the position of spark plug, improved the precision of spark plug gap dimensional measurement.
Claims (2)
1. the central electrode based on edge sub-pixel technology and the distance measurement method between ground electrode, is characterized in that, adopts whole pixel edge extractive technique and edge sub-pixel location technology to determine the position of spark plug.Then according to the attitude of coupling, to calibrating for the area-of-interest of measuring; Finally adopt one dimension edge extracting to obtain its gray level skeleton to complete the measurement to spark plug gap size.The present invention can be applicable in the fields of measurement of precision component.The realization of described whole detection method.
2. according to a kind of central electrode based on edge sub-pixel technology and the distance measurement method between ground electrode described in right 1, be further characterized in that the estimation of the registration parameter of image; Described method can complete the measurement of spark plug gap size, and can complete the functions such as data management statistics.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201310682738.6A CN103615987A (en) | 2013-12-09 | 2013-12-09 | Method for measuring distance between central electrode and ground electrode of spark plug based on edge sub-pixel technology |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201310682738.6A CN103615987A (en) | 2013-12-09 | 2013-12-09 | Method for measuring distance between central electrode and ground electrode of spark plug based on edge sub-pixel technology |
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| CN103615987A true CN103615987A (en) | 2014-03-05 |
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| CN201310682738.6A Pending CN103615987A (en) | 2013-12-09 | 2013-12-09 | Method for measuring distance between central electrode and ground electrode of spark plug based on edge sub-pixel technology |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110044285A (en) * | 2017-01-03 | 2019-07-23 | 东莞理工学院 | A kind of vision testing machine for the spark plug that can be welded |
| US10615577B2 (en) * | 2018-07-11 | 2020-04-07 | Ngk Spark Plug Co., Ltd. | Method for manufacturing spark plug |
| CN111336940A (en) * | 2020-04-22 | 2020-06-26 | 福清市鸿远科技有限公司 | Electrode gap measuring and adjusting device for spark plug |
-
2013
- 2013-12-09 CN CN201310682738.6A patent/CN103615987A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110044285A (en) * | 2017-01-03 | 2019-07-23 | 东莞理工学院 | A kind of vision testing machine for the spark plug that can be welded |
| CN110068281A (en) * | 2017-01-03 | 2019-07-30 | 东莞理工学院 | A kind of material fetching mechanism for spark plug vision-based detection |
| US10615577B2 (en) * | 2018-07-11 | 2020-04-07 | Ngk Spark Plug Co., Ltd. | Method for manufacturing spark plug |
| CN111336940A (en) * | 2020-04-22 | 2020-06-26 | 福清市鸿远科技有限公司 | Electrode gap measuring and adjusting device for spark plug |
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Application publication date: 20140305 |