CN102322798A - Industrial measuring system based on optical imaging - Google Patents

Abstract

The invention discloses an industrial measuring system based on the optical imaging, which is sequentially provided with a digital image collection module, an image pre-processing module, a characteristic extraction module, an image registering module, a three-dimensional rebuilding module, a dynamic simulation module and a data export module, wherein a digital camera is used for collecting images, the direct rebuilding problem of the non-uniform rational B-spline (NURBS) curves and surfaces can be solved in the deformation angle, and the non-contact measurement on large-scale processing workpieces (such as steel plates for making ships) can be carried out. The auxiliary imaging and positioning equipment such as structured light equipment, transits and the like are not needed, so users can complete the shooting and the complicated operation work through possibly little interactive operation and simplest equipment and environment, the requirement on the environment is reduced to the minimum, and the industrial measuring system is suitable for being used in environment with a certain illumination degree such as indoor and outdoor environment and the like, and has the advantages that the operation is simple, the precision is high, the measurement cost can be reduced, the work efficiency can be improved, and the like. The industrial measuring system belongs to a system with a high automation degree.

Description

Industrial measuring system based on optical imagery

Technical field

The present invention relates to a kind of industrial measuring system, especially a kind of simple to operate, precision is high, can reduce to measure cost, increase work efficiency, and utilizes digital camera large-scale processing work to be carried out the industrial measuring system based on optical imagery of non-cpntact measurement.

Background technology

Commercial measurement is in commercial production and each link of scientific research, is the design of product, simulation, measurement, setting-out, imitated, emulation, production quality control, product motion state, a subject that provides measuring technique to support.Commercial measurement is meant in process industry and machine erector's industry; Body to parts and product carries out accurate three-dimensional coordinate measurement; Measurement contents is main with the physical dimension of product; Also relate to color, temperature, speed and acceleration and other physical quantitys, three-dimensional commercial measurement technology is the element of commercial measurement.

At present, the method and system of large scale three-dimensional coordinate measurement can be realized, following several types can be divided into according to employed main sensors:

1. three coordinate measuring machine system

Three coordinate measuring machine is the traditional common coordinate precise measurement representative equipment that obtains the world wide widespread use at present in manufacturing industry, realizes the precise coordinates measurement through gauge head along the rectilinear motion of guide rail, has become 3D and has detected industry standard equipment.Advantage is that measurement is accurate, efficient is high, versatility good, and shortcoming is to belong to the contact type measurement mode, is difficult for the alignment characteristics point; High, not portable to requirement on measurement environment; Receive the restriction of guide rail movement, generally can only be used for special-purpose measurement environment, can not be applied to make on-the-spot; The measurement range of traditional three coordinate measuring machine is limited, generally is no more than 2 meters.

2. transit industrial measuring system

The transit industrial measuring system is the basis with spatial intersection's principle of triangulation, adopts the combination of a plurality of transits, combines the precise orientation technology, be in the large-scale metrology field application the earliest with maximum a kind of systems.Advantage is that measurement range is bigger, can reach 2m to tens meter; Be optical non-contact measurement, precision is higher, and the coordinate precision in 20 meters scopes can reach 10 μ m/m; Dirigibility is strong, can rationally lay according to the characteristics of testee, satisfies different request for utilizations.Shortcoming is: target is manually sighted in general employing, point-to-point measurement, and working strength is big, and efficiency of measurement is low, automaticity is not high, and measuring accuracy increases with measuring distance and descends; System cost is too high, is not suitable for the in-site measurement of big workload.

3. total powerstation polar coordinate measurement system

Total powerstation polar coordinate measurement system is the polar coordinate measurement system that the high-precision total powerstation of Yi Yitai constitutes, and based on the polar coordinates ratio juris, has electronics angle measurement and electronic range measurement function concurrently.Advantage is: instrument establish the station very convenient and flexible, ranging is far away, in fact the precision in the 100m scope can reach about scholar 0.5mm.Shortcoming is: be applicable to that medium accuracy such as steel frame construction measurement and shipbuilding industry require the product price higher.

4. laser tracking measurement system

Laser tracking measurement system is based on the space polar coordinate measuring principle, and two angles through the coordinate of set point is exported by follower head are based upon the polar coordinate measurement system on laser interference linear measure longimetry and the precise angle Fundamentals of Measurement.Its advantage is quick for having, dynamic, precision is high.Shortcoming is that angle measurement accuracy is lower than the total powerstation, and measurement range is also little than total powerstation, and price is higher.

5. laser scanning measurement system

Utilize laser to adopt non-interferometric method distance measuring method system to be called laser scanning measurement system

Laser tracking measurement system has the high characteristics of distance accuracy; But range finding is relatively range finding, and need remain in the tracing process laser beam can not lose, and range finding needs cooperative target (reverberator) cooperation in addition; Therefore be a kind of measuring system of contact, often bring inconvenience to measurement.

6. articulated type coordinate measuring machine

The articulated type coordinate measuring machine utilizes the principle of space open traverse to realize the three-dimensional coordinate measurement function; It also is a kind of of non-orthonormal system coordinate measuring system; Be a kind of portable instrument with contacts, to the contact of the space diverse location tested point mode of motion of anthropomorphic dummy's arm in fact.Advantage is: gauge head is settled very flexible, does not need the sighting condition of measuring point, and is therefore under the relatively poor situation of some measuring point sighting conditions, very effective.Shortcoming is: because the restriction of joint brachium, its measurement range is limited, and length can arrive 4m.

7. indoor GPS

Indoor GPS is meant and utilizes indoor Laser emission assembling device (base station) ceaselessly outwards to launch the unidirectional infrared laser that has positional information; After receiver receives signal; Therefrom obtain two angle values (being similar to the horizontal angle and the vertical angle of transit) between transmitter and receptacle; Known behind the position and azimuth information of base station, as long as there is plural base station just can calculate the three-dimensional coordinate of receiver through the method for angle intersection.The position of base station and orientation carry out accomplishing after the system oriented through flux of light method, just do not need the known control point, as long as a benchmark is just passable.Advantage: Indoor GPS has very high measuring accuracy, measuring speed and stability, can lay high-precision local space flexibly according to different measurement environment and measure system.Shortcoming: because this system need install receiver in advance on measuring object, therefore, this system is a contact, inconvenience for the measurement of the steel plate of shipyard, and measuring object is certain three-dimensional point.Price is very expensive.

In sum, existing Digital Measuring Technique generally has following shortcoming: the first, and cost is very high, purchases complete measuring equipment price up to up to a million yuans.The second, require harshness to measuring field conditions, for example, the variation meeting of measuring some light of place produces apparent in view influence to the result.The 3rd, measuring accuracy is high to equipment quality or quantity dependence.The 4th, operate strongly professionally, must under professional person's operation, just can obtain ideal results.And general digital measuring system need be installed receiver in advance on measuring object, and this system is a contact, is very inconvenient for the shipyard measurement of the steel plate.

In shipbuilding industry; The hull design of steel plate bending first being processed, setting-out, expansion, number material, cutting have all realized computerize; Thereafter assembling, welding have all realized mechanization and streamline words; Have only steel plate processing and evaluate and test these two links, both contrasted with wooden die and the target component made in advance still by manual.Like this, before making every ship, all need make a large amount of unrepeatable moulds.The method of this hand dipping has following significant disadvantages: the first, and the part dimension of general shipbuilding industry is bigger, and the method for this hand dipping will receive the restriction of place and instrument; The second, the manufacturing and the use of mould need the technical professional, and waste great amount of manpower and work efficiency are low; The 3rd, the not reproducible utilization of the mould after the use causes the waste of resource.

Summary of the invention

The present invention is in order to solve the above-mentioned technical matters of existing in prior technology; Provide a kind of simple to operate, precision is high; Can reduce the measurement cost, increase work efficiency, utilize digital camera large-scale processing work to be carried out the industrial measuring system based on optical imagery of non-cpntact measurement.

Technical solution of the present invention is: a kind of industrial measuring system based on optical imagery is characterized in that: be provided with digital image collection module, image pre-processing module, characteristic extracting module, image registration module, three-dimensional reconstruction module, dynamic simulation module and data successively and derive module.

The present invention utilizes the digital camera images acquired, solves the direct reconstruction problem of nurbs curve curved surface from the angle of distortion, can carry out non-cpntact measurement to large-scale processing work (like ship plate).The present invention can break away from the equipment of auxiliary imagings such as structured light, transit and location; Make the user accomplish the evaluation work of taking with complicated through try one's best few interactive operation and the simplest equipment and environment; Environment requirement is reduced to minimum; Can adapt to and wait environment to use indoor and outdoor with certain illumination, have simple to operate, precision is high, can reduce and measure cost and advantage such as increase work efficiency, and is the very high system of automaticity.

Description of drawings

Fig. 1 is the theory diagram of the embodiment of the invention.

Embodiment

The embodiment of the invention is as shown in Figure 1: be provided with digital image collection module, image pre-processing module, characteristic extracting module, image registration module, three-dimensional reconstruction module, dynamic simulation module and data successively and derive module.

Digital image collection module: utilize digital camera directly under the natural light condition, object under test to be carried out three-dimensional multi-angle and take; Obtain 2 ~ 5 width of cloth digital pictures; It is workable and be easy to carry, and has solved the restriction that measurement environment is caused because of utilization structure light; Support the file layout of the camera photographic images of main flow: BMP, GIF, JPG, PNG, RC2 etc.; Support the file layout of the reverse engineering software of main flow: DXF, IGS, OBJ, STL, WRL etc.;

Image pre-processing module: utilize the simple calibrating plate,, realize the full-automatic calibration and the correction of imaging system according to the camera parameter database of being set up;

Characteristic extracting module: characteristic Design on the realization object under test and the full-automatic feature extraction on the photographic images obtain area-of-interest and key feature;

Image registration module: the gray scale, the texture information that have made full use of image; Realize the image sub-pix high precision zone registration of unique point, gray scale and texture; Make registration accuracy improve greatly, the registration rate reaches more than 90%, and precision reaches 0.01 millimeter and guarantees to accomplish the high accuracy three-dimensional reconstruction;

Three-dimensional reconstruction module: utilize two dimensional image analysis software, regard image as the projection of the three-dimension curved surface that has texture represented by NURBS, will consider together based on the image registration and the three-dimensional reconstruction in zone at different directions.Carry out the space from the angle of curve and surface distortion and rebuild, be converted into the fitting problems of perspective transform lower curve curved surface problem is found the solution at the reference mark of nurbs curve curved surface, utilize the slickness of inner elastomeric energy control curve and surface simultaneously.Reduced initial value for registration point logarithm purpose demand in the different views, can utilize less registration point accomplishing curve reestablishing.Realize the high-precision three-dimensional reconstruction of the nurbs curve and the curved surface of object under test, error control is in 0.01 millimeter; The hommization of camera photographic images and CAD 3D model shows; And parameterized modeling makes that user's interactive operation is more flexible; Be convenient to the engineering staff and in general three-dimensional reverse software such as Catia, 3ds Max, UG, ProE, imageware, polyworks, SolidWorks, operate, the staff can accomplish the work of three-dimensional reconstruction and error evaluation quickly by simple visualized operation;

The dynamic simulation module: utilize three dimensional analysis software, realize human-computer interaction interface efficiently, ability is match nurbs curve and curved surface automatically, and realizes the conversion of grid and nurbs curve and curved surface as required;

Data derive module: realize the nurbs curve of reconstruction and the error evaluation between curved surface data and the cad data are provided the shape difference data and provide tutorial message.

Claims (1)

1. the industrial measuring system based on optical imagery is characterized in that: be provided with digital image collection module, image pre-processing module, characteristic extracting module, image registration module, three-dimensional reconstruction module, dynamic simulation module and data successively and derive module.

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