CN104949983B - The line scan camera imaging method of object thickness change - Google Patents
The line scan camera imaging method of object thickness change Download PDFInfo
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- CN104949983B CN104949983B CN201410120138.5A CN201410120138A CN104949983B CN 104949983 B CN104949983 B CN 104949983B CN 201410120138 A CN201410120138 A CN 201410120138A CN 104949983 B CN104949983 B CN 104949983B
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Abstract
The present invention relates to a kind of Machine Vision Detection and fields of measurement.A kind of line scan camera imaging method of object thickness change, by camera（2）And light source（1）Detecting system imaging optical path is formed with the angle of setting, configuration plane microscope group, light are sent from light source on the reflected light path of object to be imaged light, by imaging surface（3）After reflection, then enter camera imaging after plane microscope group；Plane microscope group includes the first level crossing（4）With the second level crossing（5）, the first level crossing and the second level crossing reflecting surface are relative and parallel, and the first level crossing and the second level crossing are rotated with crossing the length direction rotary shaft at width midpoint respectively, and mutual distance can be adjusted；When object to be imaged apparent height changes, by adjusting the distance between plane microscope group and angle, the constant situation of former imaging source and camera position is maintained, still can be effectively imaged.In the surface detecting system changed greatly present invention can apply to steel slab, copper strips equal thickness.
Description
Technical field
The present invention relates to the line scanning of a kind of Machine Vision Detection and fields of measurement, more particularly to a kind of change of object thickness
Camera imaging method.
Background technology
Machine Vision Detection and e measurement technology based on CCD imagings have detection speed fast, smart using image as detection medium
The advantages that degree is high, examination criteria uniformity is good, is widely used in socialization large-scale production process.Wherein, phase is scanned based on line
The surface quality of strips online measuring technique of machine, the visual image of surface defect is preserved as a result, it is possible to generate textual and quantify
The quality report of change, it has also become the important supplementary means of quality control.
In strip production industry, machine vision Surface Quality Inspection System, which has been similarly obtained, to be widely applied, and is fully demonstrated
The technology adapts to that high speed detection, detection performance be stable, reliably advantage, can replace operator's work in the presence of a harsh environment.
During band steel thick plate Surface testing, the thickness change of sheet material is very big（50-450mm）, the change considerably beyond camera into
The depth of field of picture, surface effectively imaging need image-forming block（Light source 1, camera 2）Integral position changes, to adapt to slab strip height
Change, as shown in Figure 1.The movement of image-forming block will ensure that light path is constant, then need to move integrally the light source 1 of imaging
With camera 2, in application process frequently and micro movement makes system design become complicated, equipment attrition can also reduce system into
As precision.
Through the Searches of Patent Literature, it is more to be related to the patent of line scan camera imaging and camera calibration, but is specific to imaging
The patent that distance change is adjusted to picture is seldom.Chinese patent 200710046375.1 discloses a kind of strip tracking imaging vision inspection
Survey method, this method be it is a kind of strip curling position increase with coil diameter during the method for synchronous adjustment light source and camera imaging,
This method needs mobile camera and light source, and the diameter change for needing monitoring band to roll up, this method are complicated simultaneously.
The content of the invention
It is an object of the invention to provide a kind of line scan camera imaging method of object thickness change, this method is limited
Under conditions of adjusting image-forming block, the image acquisition process to variable height object is realized, can be with by the adjustment of image-forming block
Do not change imaging optical path and imaging resolution is effectively imaged.
In order to realize above-mentioned technical purpose, the present invention adopts the following technical scheme that：
A kind of line scan camera imaging method of object thickness change, detection is formed by camera and light source with the angle set
System imaging light path, configuration plane microscope group, light are sent from light source on the reflected light path of object to be imaged light, by imaging
After the reflection of surface, then enter camera imaging after plane microscope group；The plane microscope group includes the first level crossing and the second level crossing,
First level crossing and the second level crossing reflecting surface are relative and parallel, and the first level crossing and the second level crossing are respectively with width midpoint excessively
Length direction rotary shaft rotate, and the distance between the first level crossing and the second level crossing can be adjusted；
When object to be imaged apparent height changes, by adjusting the distance between plane microscope group and angle, maintain it is former into
As light source and the constant situation of camera position, still can effectively be imaged.
In the detecting system imaging optical path, if：Light source incidence angle isβ, light is through object angle of reflectionα, when being taken
When object thickness changes H ', camera imaging change in optical path length 2l ' can be caused, the position d ' that shifts enters according to given light path
Firing angle and angle of reflection, its calculating formula are：
（1）
In formula：L ' -- camera imaging change in optical path length；
D ' -- position shifts；
β--Light source incidence angle；
α-- light angle of reflection；
H ' -- subject thickness change；
To ensure imaging effect and parameter constant, height change and transverse direction that speculum group comes compensating image position need to be adjusted
Offset；If the second level crossing is fixed closer to camera, the second level crossing widthwise central O points position, the length side of O points was adjusted
To axis rotate, its anglec of rotation isθ, define the anglec of rotationθFor minute surface and the angle of horizontal direction；The position of first level crossing
Put by its width midpoint O ' determination, positioned especially by relative O point height H and lateral shift D, the first level crossing anglec of rotation
Spend and be alsoθ；
（2）
Wherein：（3）
In formula：L ' -- camera imaging change in optical path length；
D ' -- position shifts；
α-- light angle of reflection；
θ—The angle of first, second level crossing minute surface and horizontal direction；
The level crossing width midpoint O ' of H-- the first and the second level crossing width midpoint O vertical heights；
D -- the first level crossing width midpoint O ' and the second level crossing width midpoint O lateral separations；
Wherein：L ', d ' are by formula（1）Obtain, light angle of reflectionαFor, it is known that so as to pass through formula（2）With（3）Calculate
Obtain H,θAnd D.
The second level crossing anglec of rotationθValue：90 °-α>θ>-（90°+α）.
First level crossing and the second level crossing are strip.
The line scan camera imaging method of the present invention is realized to variable height thing under conditions of limited adjustment image-forming block
The image acquisition process of body, by the adjustment of image-forming block, imaging optical path can not be changed and imaging resolution is effectively imaged.From
And overcome when subject image-forming range changes greatly, more than the camera lens depth of field when need accurate adjustment camera and light source position
Deficiency, increase detecting system in image capture module applicability.
The imaging method of the present invention is specifically to propose that a kind of mirror-reflection by rotating and adjusting one group of plane microscope group changes
Become the method for light path, when realizing the change of object to be imaged apparent height, do not change light source position, only by adjusting units of variance
Realize light path it is constant, etc. resolution imaging.
The imaging method of the present invention can be applied in the surface detecting system that steel slab equal thickness changes greatly.Slab table
, it is necessary to consider influence of the strip thickness change to imaging effect while planar defect detecting system needs to consider temperature protection, it is
Ensure the definition of imaging effect and the stability of resolution ratio, it is necessary to adjust the height of image-forming block.The present invention passes through tune
Whole one group of light ray bending device, realizes the adjustment and control to light path, reaches IMAQ critical component（Camera and light
Source）The constant imaging effect for being but adapted to plank thickness change in position.With online based on machine vision strip surface quality
Detection technique popularizes application, and the present invention has extensive market application foreground.
The imaging method of the present invention can be applied in steel slab, the surface detecting system that copper strips equal thickness changes greatly.
Brief description of the drawings
Fig. 1 is image-forming module height with object thickness change schematic diagram；
Fig. 2 is the light path Variable reflectance microscope group schematic diagram of the present invention；
Fig. 3 is the speculum group position relationship schematic diagram of the present invention；
Fig. 4 adjusts speculum group distance and angle schematic diagram when being the image height change of the present invention；
Speculum group distance and angle signal when Fig. 5 is the camera imaging light vertical subject surface of the present invention
Figure.
In figure：1 light source, 2 cameras, 3 imaging surfaces, 4 first level crossings, 5 second level crossings, 11 first level crossing light enter
Penetrate direction and vertical direction angle, 12 first level crossing beam projecting directions and vertical direction angle, 13 first level crossings and the
The normal direction of two level crossings and horizontal direction angle, 14 first level crossings and the second level crossing and vertical direction angle, 15 the
Two level crossing beam projecting directions and vertical direction angle.
Embodiment
The invention will be further described with specific embodiment below in conjunction with the accompanying drawings.
A kind of line scan camera imaging method of object thickness change, inspection is formed by camera 2 and light source 1 with the angle of setting
Examining system imaging optical path, the configuration plane microscope group on the reflected light path of object to be imaged light, light are sent from light source 1, are passed through
After imaging surface 3 reflects, then it is imaged after plane microscope group 4,5 into camera 2；The plane microscope group includes the He of the first level crossing 4
Second level crossing 5, the first level crossing 4 and the reflecting surface of the second level crossing 5 be relative and parallel, the first level crossing 4 and the second level crossing 5
For strip, the first level crossing 4 and the second level crossing 5 are rotated with crossing the length direction rotary shaft at width midpoint respectively, and the
The distance between one level crossing 4 and the second level crossing 5 can be adjusted.It is flat by adjusting when object to be imaged apparent height changes
The distance between face microscope group and angle, the constant situation of former imaging source and camera position is maintained, still can be effectively imaged, joined
See Fig. 4.It is specific as follows：
As shown in figure 3, this group of level crossing is the first level crossing 4 and the second level crossing 5, the first level crossing 4 and the second plane
The reflecting surface of mirror 5 is relative and parallel, and the first level crossing 4 and the second level crossing 5 are strip, width 20-100mm, length according to
Specific to apply to determine, suitable with the imaging suite visual field of camera 2, the first level crossing 4 and the second level crossing 5 can be respectively with mistakes
The length direction rotary shaft at width midpoint is rotated, i.e. rotary shaft is arranged on minute surface length direction, and rotary shaft is turned with width midpoint
Dynamic, the anglec of rotation isθ, define the anglec of rotationθFor minute surface and the angle of horizontal direction, and the first level crossing 4 and the second plane
The distance between mirror 5 can be adjusted, the horizontal range between specially the first level crossing and the second level crossingDAnd vertical distanceH
Regulation.
Camera 2（Imaging sensor）Receive the image formation by rays reflected by plane microscope group 4,5, when object to be imaged thickness becomes
During change, by adjusting the angle and distance of plane microscope group 4,5, realize to body surface image space height change and position skew
Compensation.As shown in Fig. 2 in detecting system imaging optical path, if：Light source incidence angle isβ, light is through object angle of reflectionα, work as quilt
When shooting object thickness change H ', camera imaging change in optical path length 2l ' can be caused, position shifts d ' according to given detection light
Road incidence angle and angle of reflection, its calculating formula are：
（1）
In formula：L ' -- camera imaging change in optical path length；
D ' -- position shifts；
β--Light source incidence angle；
α-- light angle of reflection；
H ' -- subject thickness change；
To ensure imaging effect and parameter constant, it is necessary to by adjusting speculum group come the height change of compensating image position
And transversal displacement.As shown in figure 3, setting the second level crossing 5 closer to camera 2, in position adjustment, the second level crossing 5 is wide
Degree center O points position is fixed, and adjusts the axis rotation of the length direction of O points, and its anglec of rotation isθ, define the anglec of rotationθFor
The angle of minute surface and horizontal direction.The position of first level crossing 4 is high especially by relative O points by its width midpoint O ' determination
H and lateral shift D is spent to position, and the anglec of rotation of the first level crossing 4 is alsoθ, so ensure the first level crossing 4 and the second level crossing
5 is parallel, and the light reflecting surface of the first level crossing 4 is relative with the second level crossing 5.Thus the phase between plane microscope group and light
Position is fixed, and can be calculated.
As shown in Figure 3, the first level crossing light incident direction and vertical direction angle 11, the second level crossing beam projecting side
It is to the angle 15 with vertical direction angleα, level crossing is with horizontal direction angle 13θ, level crossing normal direction with it is vertical
Angular separation 14 isθ, thereby determine that the angle of incidence of light of plane microscope group and reflection angle be angle 14 and angle 15 and, i.e.,α+θ；
First level crossing 4 and the anglec of rotation of the second level crossing 5θValue：90 °-α>θ>-（90°+α）.Further, it is flat that first can be calculated
Catoptric light line exit direction is with vertical direction angle 12α+ 2θ.Thus reflection optical path difference, image space skew and reflection are established
The relational expression of mirror position：
（2）
Wherein：（3）
In formula：L ' -- camera imaging change in optical path length；
D ' -- position shifts；
α-- light angle of reflection；
θ—The angle of first, second level crossing minute surface and horizontal direction；
The level crossing width midpoint O ' of H-- the first and the second level crossing width midpoint O vertical heights；
D -- the first level crossing width midpoint O ' and the second level crossing width midpoint O lateral separations；
Wherein：L ', d ' are by formula（1）Obtain, light angle of reflectionαFor, it is known that so as to pass through formula（2）With（3）Calculate
Obtain H,θAnd D.According to being calculatedH、DWithθPlane microscope group 4,5 is adjusted to determination position, you can be effectively imaged.
Referring to Fig. 4, the widthwise central O points position of the second level crossing 5 is fixed, an anglec of rotationθ, the angle is with body surface
The raising of height and increase, 90 ° as shown in Figure 3-α>θ>-（90°+α）.First level crossing 4 then needs to enter row distance adjustment simultaneously
And angle adjustment, angle change change and become with the second level crossing 5, strict keeping parallelism.Change in location is calculated by above-mentioned
Arrive.As shown in Figure 4, when object thickness by it is thin thickening when, i.e., B is changed to by A, the first level crossing 4 and the second level crossing 5 are apart from change
Greatly, the anglec of rotationθIt is also required to become big.
In particular cases, when camera imaging angleαWhen=0, referring to Fig. 5, the i.e. vertical subject body surface of camera imaging light
During face, during subject thickness change, the relative position height and angle of level crossing are only adjusted.
Although it is to be herein pointed out the widthwise central O points position of the second level crossing 5 is consolidated in the embodiment of this case
It is fixed, adjust its anglec of rotationθ, and then the distance and the anglec of rotation of the first level crossing 4 are adjusted again, this embodiment is relatively easy
With it is preferable.It is other such as：The widthwise central point position of first level crossing 4 is fixed, and adjusts its anglec of rotationθ, and then second is adjusted again
The distance and the anglec of rotation of level crossing 5；And the distance and the anglec of rotation of the first level crossing 4 of adjustment and the second level crossing 5, and
Meet the invention thinking of the present invention.
Presently preferred embodiments of the present invention is these are only, is not intended to limit the protection domain of invention, it is therefore, all at this
Any modification, equivalent substitution and improvements made within the spirit and principle of invention etc., should be included in protection scope of the present invention
Within.
Claims (4)
1. a kind of line scan camera imaging method of object thickness change, it is characterized in that：
Camera and light source are formed into detecting system imaging optical path with the angle set, on the reflected light path of object to be imaged light
Configuration plane microscope group, light are sent from light source, after imaging surface reflects, then enter camera imaging after plane microscope group；Institute
Stating plane microscope group includes the first level crossing and the second level crossing, and the first level crossing and the second level crossing reflecting surface are relative and parallel,
First level crossing and the second level crossing are rotated with crossing the length direction rotary shaft at width midpoint respectively, and the first level crossing and the
The distance between two level crossings can be adjusted；
When object to be imaged apparent height changes, by adjusting the distance between plane microscope group and angle, former imaging is maintained
Source and the constant situation of camera position, still can effectively be imaged.
2. the line scan camera imaging method of object thickness change according to claim 1, it is characterized in that：The detection system
In system imaging optical path, if：Light source incidence angle isβ, light is through object angle of reflectionα, as subject thickness change H ', meeting
Cause camera imaging change in optical path length 2l ', position shifts d ' according to given light path incidence angle and angle of reflection, and it is calculated
Formula is：
（1）
In formula：L ' -- camera imaging change in optical path length；
D ' -- position shifts；
β--Light source incidence angle；
α-- light angle of reflection；
H ' -- subject thickness change；
To ensure imaging effect and parameter constant, height change and lateral shift that speculum group comes compensating image position need to be adjusted
Amount；If the second level crossing is fixed closer to camera, the second level crossing widthwise central O points position, the length direction of O points was adjusted
Axis rotates, and its anglec of rotation isθ, define the anglec of rotationθFor minute surface and the angle of horizontal direction；The position of first level crossing leads to
Its width midpoint O ' determination is crossed, is positioned especially by relative O point height H and lateral shift D, the first level crossing anglec of rotation
Forθ；
（2）
Wherein：（3）
In formula：L ' -- camera imaging change in optical path length；
D ' -- position shifts；
α-- light angle of reflection；
θ—The angle of first, second level crossing minute surface and horizontal direction；
H-- the first level crossing width midpoint O ' and the second level crossing width midpoint O vertical heights；
D -- the first level crossing width midpoint O ' and the second level crossing width midpoint O lateral separations；
Wherein：L ', d ' are by formula（1）Obtain, light angle of reflectionαFor, it is known that so as to pass through formula（2）With（3）It is calculated
H、θAnd D.
3. the line scan camera imaging method of object thickness change according to claim 2, it is characterized in that：Described second is flat
The face mirror anglec of rotationθValue：90 °-α>θ>-（90°+α）.
4. the line scan camera imaging method of object thickness change according to claim 1 or 2, it is characterized in that：Described
One level crossing and the second level crossing are strip.
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| CN107292931A (en) * | 2016-03-30 | 2017-10-24 | 宝山钢铁股份有限公司 | The line scan camera detected for strip surface, which is turned back, is imaged calibration system and method |
| CN106442327B (en) * | 2016-12-08 | 2024-02-20 | 苏州德创测控科技有限公司 | Optical system for detecting object side image information |
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| CN111521618B (en) * | 2020-04-27 | 2023-01-31 | 衢州职业技术学院 | Rapid bearing defect detection device for industrial robot and detection method thereof |
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