CN101865721A - New method for automatically measuring weight of propeller blades - Google Patents
New method for automatically measuring weight of propeller blades Download PDFInfo
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- CN101865721A CN101865721A CN201010106005A CN201010106005A CN101865721A CN 101865721 A CN101865721 A CN 101865721A CN 201010106005 A CN201010106005 A CN 201010106005A CN 201010106005 A CN201010106005 A CN 201010106005A CN 101865721 A CN101865721 A CN 101865721A
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- weight
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Abstract
The invention provides a new method for automatically measuring the weight of propeller blades, which takes an image as a basis to carry out non-contact automatic measurement of the weight of the propeller blades. The method comprises the following steps: firstly collecting the image of the propeller blades by adopting equipment such as a computer, a projector, a camera and the like; acquiring the coordinate of a two-dimensional image coordinate system of all projective points of the blades by taking a digital image processing technology as a basis; calculating the coordinate of a three-dimensional real-world coordinate system of all the projective points of the blades by adopting a camera calibration model; and finally calculating the weight of the propeller blades by the computer.
Description
Technical field:
The invention belongs to screw propeller and measure association area, particularly a kind of contactless new method for automatically measuring of the weight of propeller blades based on image.
Technical background:
Screw propeller is one of Ship Propeling most important equipment, because screw propeller is suspended on outside the stern tube shaft pipe, the effect of screw propeller weight certainly will advance the effect important influence to it.Workmanship in order to ensure screw propeller, country's technical supervision department has carried out standard to the weight of all size screw propeller, the quality of each screw propeller factory in order to guarantee that screw propeller is produced needs the weight of propeller blade is carried out repeatedly measurement in screw propeller manufacturing process.By the measurement of weight of propeller blades, can provide foundation for the accurate adjustment that the blade processing capacity is carried out in the technical requirement of satisfying Design of Propeller.Therefore the convenient weight of measuring propeller blade is exactly made quality for the control screw propeller and is had great importance.
Because the bulky of large-scale spiral oar, the method for can not application directly weighing is carried out the measurement of weight.At present, weight of propeller blades generally is to measure each point coordinate of blade by measuring machine to calculate the propeller blade volume, calculates weight then.These coordinate measuring machines are the coordinates that obtain the blade measurement point by the mode that measuring staff and gauge head directly contact propeller blade, need to determine one by one the position measured when therefore measuring, and the coordinate measuring machine that has also needs the manual record measurement data.In measuring process, existing coordinate measuring machine needs pointwise to determine the position of each cross section and measurement point, and the hard work that causes thus usually causes artificial measurement mistake.In addition, gauge head need contact the metal surface of blade when existing coordinate measuring machine was measured, and the wearing and tearing that long-term use causes also can cause measuring error.Therefore, the existing coordinate measuring machine of above-mentioned factor affecting carries out the accurate measurement of propeller blade.In addition, existing coordinate measuring machine utilizes rotary axis, beam type transverse arm and travelling carriage to support and mobile measuring staff gauge head carries out the measurement of screw propeller different cross section, it is this because the cross arm structure nonlinear deformation that factors such as deadweight cause also influences the further raising of measuring accuracy.
The present invention is the automatic new measurement method of relevant weight of propeller blades.The weight of propeller blades new method of measuring that the present invention proposes is to utilize image to carry out the contactless and digitized measurement of propeller blade.The measuring method of utilizing the present invention to propose can be carried out the measurement of weight of propeller blades quickly and easily.Because what the present invention proposed is non-contact digital measuring method, different with the principle of existing screw propeller weight measurement, therefore can solve the deficiency of existing screw propeller measuring method.Based on the weight of propeller blades new method of measuring that the present invention proposes, can carry out the automatic measurement of weight of propeller blades.Therefore, the present invention will make quality new effective detection means will be provided for guaranteeing screw propeller.
Summary of the invention:
The objective of the invention is with the image is the contactless all automatic measurement that weight of propeller blades is carried out on the basis.When utilizing this method to carry out the measurement of weight of propeller blades, do not need the gauge head contact screw propeller metal surface of measuring equipment, belong to contactless full-automatic measuring method.
In order to reach above-mentioned target, the technical solution used in the present invention is: utilize digital projector that the projection dot matrix that computing machine generates automatically is incident upon screw propeller to be measured surface, utilize ccd video camera to obtain the image of propeller blade, blade image is carried out digitized processing, obtain the two dimensional image coordinate system pixel coordinate of all subpoints, utilize through the camera model of demarcating and carry out the mapping that all subpoint two-dimensional pixel coordinates of blade to three-dimensional real-world coordinates are, obtain the three-dimensional coordinate that all subpoints in three-dimensional real-world coordinates are according to the binocular vision Theoretical Calculation, make up the three-dimensional coordinate model of blade, and utilize the weight of COMPUTER CALCULATION propeller blade.
The present invention includes several steps such as the structure that computing machine generates and collection, all subpoint two dimensional image coordinate system pixel coordinates of blade image obtain, the three-dimensional real-world coordinates of all subpoints are coordinate Calculation, propeller blade three-dimensional coordinate model of projection dot matrix and blade Weight Calculation.The concrete steps that the present invention includes are as follows:
1) collection of generation of the computing machine of projection dot matrix and blade image
Generate dot matrix according to blade shape by computer programming, utilize projector that dot matrix is incident upon propeller blade to be measured surface, utilize 2 ccd video cameras to set up the binocular vision image capturing system, adopt suitable illumination in case of necessity, collection comprises the blade blade face of subpoint and each 2 width of cloth of picture rich in detail of blade back respectively.
2) subpoint two dimensional image coordinate system pixel coordinate obtains
At the blade blade face that collects and the image of blade back, carry out the digitized processing of image, obtain the two dimensional image coordinate system pixel coordinate of all subpoints with this.
3) the three-dimensional real-world coordinates of subpoint is a coordinate Calculation
According to the transformation relation between video camera imaging model, camera coordinate system and the three-dimensional real-world coordinates system, set up the projection matrix of reflection propeller blade all subpoint pixel coordinates of surface and three-dimensional real-world coordinates relation, setting up based on the three-dimensional real-world coordinates of all subpoints of pixel coordinate by the demarcation of projection matrix is the Coordinate Calculation model.The three-dimensional real-world coordinates of utilizing the binocular vision principle to calculate all subpoints is a coordinate.
4) structure of propeller blade three-dimensional coordinate model
Three-dimensional real-world coordinates based on blade blade face and blade back surface projection's point is a coordinate, three-dimensional coordinate to blade back surface projection's point carries out conversion, make the three-dimensional coordinate of itself and propeller blade blade face subpoint form relative position relation one to one, make up the three-dimensional coordinate model of propeller blade.
5) calculating of weight of propeller blades
Based on the propeller blade three-dimensional coordinate model that makes up, obtain the weight of propeller blade by utilizing the volume and weight of COMPUTER CALCULATION blade unit cube, finally adding up.
Advantage of the present invention: the present invention is to be the contactless automatic measurement that weight of propeller blades is carried out on the basis with the image, so the present invention has contactless and advantage digitized measurement.The present invention does not need directly to contact the metal surface of blade, does not have defectives such as gauge head wearing and tearing.This method can realize the automatic measurement of weight of propeller blades easily, and therefore, the present invention can be for the shortening screw propeller process-cycle, reducing production costs provides effective measurement means.
Description of drawings:
Accompanying drawing 1 is the step of weight of propeller blades new method for automatically measuring;
Accompanying drawing 2 is weight of propeller blades automatic measurement system structural drawing;
Accompanying drawing 3 is video camera imaging model synoptic diagram;
Accompanying drawing 4 is that weight of propeller blades calculates synoptic diagram.
Embodiment:
Below in conjunction with accompanying drawing, the automatic new measurement method of the weight of propeller blades based on image method that the present invention proposes is described, its know-why and specific implementation method are as follows:
Fig. 1 is the key step of weight of propeller blades method for automatic measurement, this method is measured with the method for image, at first generate the projection dot matrix and be incident upon screw propeller surface and images acquired by computer programming, obtain the two dimensional image coordinate system pixel coordinate of all subpoints of blade blade face and blade back surface then, and be coordinate according to the three-dimensional real-world coordinates of all subpoints of binocular vision Theoretical Calculation, make up the three-dimensional coordinate model of propeller blade based on this and calculate blade weight.The present invention just can realize the automatic measurement of weight of propeller blades according to this step.
Fig. 2 is the system architecture synoptic diagram that weight of propeller blades is measured automatically.By digital projector the dot matrix that computing machine generates automatically is incident upon the propeller blade surface, utilizes two video camera L and R images acquired.In the camera coordinates system, the X-axis of video camera L and R overlaps, and Y-axis and Z axle are parallel to each other respectively, Z-direction is the camera light direction of principal axis, L is consistent with change in coordinate axis direction in the R coordinate system, and the XOY face is parallel to the plane of delineation, simultaneously initial point (photocentre) side-play amount of video camera L and R is fixed.This has just guaranteed the consistance of the Z-direction coordinate of propeller blade tested point in two camera coordinates systems and the determinacy of measuring system.
Fig. 3 is a video camera imaging model synoptic diagram, and comprising three-dimensional real-world coordinates in this model is O
wX
wY
wZ
w, camera coordinate system O
cX
cY
cZ
c, image coordinate system O
0UV (unit is a pixel), image physical coordinates are O
1XY (unit is a millimeter).The imaging process of blade is exactly the transfer process between above four coordinate systems.Among the present invention,, realize that two dimensional image coordinate system coordinate is a Coordinate Calculation to three-dimensional real-world coordinates according to the depth information of all subpoints of binocular imaging Theoretical Calculation.
(U V) is two dimensional image coordinate system pixel coordinate to note; (X is a coordinate for the image physical coordinates Y); (X
c, Y
c, Z
c) be two dimensional image coordinate system pixel coordinate; (X
w, Y
w, Z
w) for real-world coordinates is a three-dimensional coordinate, the calculated relationship between each coordinate system is as follows:
1) two dimensional image coordinate system pixel coordinate and image physical coordinates are the coordinate Calculation relation
Wherein, (U
0, V
0) for the image physical coordinates be XO
1The coordinate round dot of Y, dx, dy are respectively on the image planes each pixel along the physical size of X-axis and Y direction.
2) physical coordinates of note subpoint in the image of the left and right sides is that coordinate is respectively (X
L, Y
L) and (X
R, Y
R), according to the binocular camera imaging theory, camera coordinate system coordinate and image physical coordinates are that the relation of coordinate is as follows:
f/Z
c＝X
L/X
c
f/Z
c＝X
R/(X
c-b)
f/Z
c＝Y
L/Y
c＝Y
R/Y
c
Thus, can calculate the depth information of this subpoint:
Z
c＝fb/|X
L-X
R| (2)
Wherein, f is used focus of camera in the measuring system of the present invention, and b is the distance of left and right cameras photocentre.
3) three-dimensional real-world coordinates is coordinate and camera coordinate system coordinate Calculation relation
Wherein, R is the rotation matrix of 3*3, and T is the translation matrix of 3*1,0=(0,0,0)
T
Therefore, image coordinate system two-dimensional pixel coordinate and real-world coordinates are that calculated relationship between the three-dimensional coordinate is as follows:
Among the present invention, at first set the camera calibration template, based on the imaging model of video camera, be the corresponding relation of coordinate according to the pixel coordinate and the three-dimensional real-world coordinates of calibration point, find the solution the inside and outside parameter (being rotation matrix R and translation matrix T) of video camera and calculate the distortion factor of camera lens.Application image coordinate system two-dimensional pixel coordinate and real-world coordinates are the calculated relationship between the three-dimensional coordinate then, and the three-dimensional real-world coordinates of calculating all subpoints is a coordinate.
Fig. 4 is that weight of propeller blades calculates principle schematic, in the measuring method of the present invention, the weight of propeller blades Calculation Method is described below: propeller blade blade face and all subpoint two dimensional image pixel coordinates of blade back that obtain with Digital Image Processing at first, and the image physical coordinates that calculates all subpoints according to formula (1) is a coordinate; Calculate the depth information of all subpoints then according to formula (2), and the three-dimensional real-world coordinates of calculating all subpoints according to formula (3) based on this is a coordinate; Last three-dimensional coordinate based on subpoint, the measurement point of choosing the next-door neighbour successively constitutes square (square T as shown in FIG.), volume by all squares of COMPUTER CALCULATION also adds up successively, according to the weight of the density calculation screw propeller entire blade of screw propeller material.
Claims (4)
1. the new method for automatically measuring of weight of propeller blades is characterized in that with the image being the non-contact measurement that weight of propeller blades is carried out on the basis, may further comprise the steps:
The computing machine generation of projection dot matrix and the collection of blade image;
All subpoint two dimensional image coordinate system pixel coordinates obtain;
The three-dimensional real-world coordinates of all subpoints is a coordinate Calculation;
The structure of propeller blade digital model;
The calculating of weight of propeller blades.
2. the new method for automatically measuring of weight of propeller blades according to claim 1, it is characterized in that: the calculating of all subpoint two dimensional image coordinate system pixel coordinates of described propeller blade, generate the projection dot matrix by computing machine and be incident upon the propeller blade surface, utilize ccd video camera to gather the image of propeller blade to be measured, appliance computer Digital Image Processing algorithm extracts the two dimensional image coordinate system pixel coordinate of all subpoints of propeller blade.
3. the new method for automatically measuring of weight of propeller blades according to claim 1, it is characterized in that: the three-dimensional real-world coordinates of described all subpoints of propeller blade is in the process of coordinate Calculation, comprises that the demarcation of the ccd video camera of gathering the propeller blade image, the rectification of distortion of camera model, three-dimensional real-world coordinates are Coordinate Calculation.
4. the new method for automatically measuring of weight of propeller blades according to claim 1, it is characterized in that: the calculating of described weight of propeller blades is based on all the subpoint three-dimensional coordinates of propeller blade that calculate, by the calculating of computer realization weight of propeller blades.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010106005A CN101865721A (en) | 2010-02-05 | 2010-02-05 | New method for automatically measuring weight of propeller blades |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010106005A CN101865721A (en) | 2010-02-05 | 2010-02-05 | New method for automatically measuring weight of propeller blades |
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| CN101865721A true CN101865721A (en) | 2010-10-20 |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102087133A (en) * | 2010-12-22 | 2011-06-08 | 重庆理工大学 | Method and device for measuring volume of bomb chamber |
| WO2011120202A1 (en) * | 2010-04-01 | 2011-10-06 | 南京太阳升科技有限公司 | New method for propeller digital detection |
| CN102954830A (en) * | 2011-08-31 | 2013-03-06 | 深圳富泰宏精密工业有限公司 | Electronic weighing method and system |
| CN108225503A (en) * | 2018-01-15 | 2018-06-29 | 贵州大学 | Electronic scale based on ccd image sensor |
| CN109211388A (en) * | 2018-08-30 | 2019-01-15 | 哈尔滨飞机工业集团有限责任公司 | A kind of weighing technique of composite material blade weight and its meausring apparatus |
| CN109827646A (en) * | 2018-12-21 | 2019-05-31 | 太原重工股份有限公司 | Weighing method and weighing device for powder material |
| CN114414011A (en) * | 2021-12-14 | 2022-04-29 | 湖南中联重科新材料科技有限公司 | Control method and device for metering screw, controller and metering screw |
-
2010
- 2010-02-05 CN CN201010106005A patent/CN101865721A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011120202A1 (en) * | 2010-04-01 | 2011-10-06 | 南京太阳升科技有限公司 | New method for propeller digital detection |
| CN102087133A (en) * | 2010-12-22 | 2011-06-08 | 重庆理工大学 | Method and device for measuring volume of bomb chamber |
| CN102087133B (en) * | 2010-12-22 | 2012-06-27 | 重庆理工大学 | Method and device for measuring volume of bomb chamber |
| CN102954830A (en) * | 2011-08-31 | 2013-03-06 | 深圳富泰宏精密工业有限公司 | Electronic weighing method and system |
| CN108225503A (en) * | 2018-01-15 | 2018-06-29 | 贵州大学 | Electronic scale based on ccd image sensor |
| CN109211388A (en) * | 2018-08-30 | 2019-01-15 | 哈尔滨飞机工业集团有限责任公司 | A kind of weighing technique of composite material blade weight and its meausring apparatus |
| CN109827646A (en) * | 2018-12-21 | 2019-05-31 | 太原重工股份有限公司 | Weighing method and weighing device for powder material |
| CN114414011A (en) * | 2021-12-14 | 2022-04-29 | 湖南中联重科新材料科技有限公司 | Control method and device for metering screw, controller and metering screw |
| CN114414011B (en) * | 2021-12-14 | 2024-04-12 | 中联重科新材料科技有限公司 | Control method and device for metering screw, controller and metering screw |
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Application publication date: 20101020 |