CN110332924B - Dilution instrument space vision positioning deviation correction method based on double linear array CCD - Google Patents

Dilution instrument space vision positioning deviation correction method based on double linear array CCD Download PDF

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CN110332924B
CN110332924B CN201910764374.3A CN201910764374A CN110332924B CN 110332924 B CN110332924 B CN 110332924B CN 201910764374 A CN201910764374 A CN 201910764374A CN 110332924 B CN110332924 B CN 110332924B
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CN110332924A (en
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张贵阳
李东博
方乃文
魏荣婕
李慧子
迟木子
王山
王宽
于春洋
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Harbin Bojue Technology Co Ltd
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    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
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Abstract

The invention relates to a dilution instrument space vision positioning deviation correction method based on a double-linear-array CCD. Aiming at the problems existing in the current diluter, in order to improve the liquid preparation accuracy and efficiency of the diluter, enhance the stability and yield of the product in practical use, and reduce or even eliminate instrument damage and accidents caused by positioning errors, the invention adopts a double-linear array CCD measurement mode to position sample bottles on a diluter platform. The rapidity effect achieved by the invention is embodied in that the positioning system provides the global spatial distribution of the sample bottles, and the execution unit can accelerate to directly reach the position of the task bottle instead of the traditional detection and uniform-speed forward.

Description

Dilution instrument space vision positioning deviation correction method based on double linear array CCD
Technical Field
The invention relates to the technical field of dilution instrument space vision positioning, in particular to a dilution instrument space vision positioning deviation correction method based on a double-linear-array CCD.
Background
The liquid medicine diluter has higher precision than the traditional manual liquid preparation, and avoids the repetitive work of operators. In the working process of the dilution instrument, a needle head on the injection pump needs to be accurately aligned to a sample bottle on the table body, if a system has large positioning deviation or even positioning error, the needle head can pierce the position of a non-target sample bottle, and the conditions of needle head bending, sample bottle damage or even driving motor rotation blockage, table body damage and the like are caused.
The needle positioning method of the injection pump of the dilution instrument used at present mainly comprises two methods, the first method is to adopt a position type sensor, such as a grating ruler, an encoder, an angle instrument and the like, and determine the current position by recording the stroke of a driving motor or a movement mechanism. The limitation of this method is that the sample bottles must be placed at specific positions and sequenced in turn, if only one or a few of the sample bottles need to be dispensed according to a specific requirement, the diluter system needs to reset parameters, which results in interruption of operation, and the system operation process is not flexible while the batch dispensing efficiency is affected. The second method is an image sensor based position location method. The method has the disadvantages that because the image has the influence of distortion and environmental noise, the pixel deviation of image positioning can be converted into the actual physical distance deviation, thereby seriously influencing the positioning precision; in addition, in order to ensure the imaging quality of the visual sensor, a limited scanning area needs to be limited, so that the global distribution condition of the sample bottles cannot be estimated, and therefore, a moving device where the probe is located can only continuously scan forwards at a constant speed until a task bottle appears, so that the moving device cannot run forwards at a high speed, and the liquid distribution efficiency cannot be effectively improved. The method is characterized in that a visual three-dimensional positioning technology is not adopted in the existing dilution instrument through searching the existing databases such as documents and patents, and the visual three-dimensional positioning technology is introduced into the product of the inventor to acquire the space position coordinates of the sample bottle. However, in the test process, the positioning accuracy of the sample bottle has certain deviation due to the influences of imaging quality, optical structure deviation, sensor spatial distribution and the like, and the positioning deviation of the dilution instrument is corrected by considering the correlation effect of the generalized deviation effect instead of adopting a certain deviation influence factor which is traditionally single and faces fixed parameters, so that the positioning accuracy in the operation process of the dilution instrument is improved.
Disclosure of Invention
The invention provides a dilution instrument space vision positioning deviation correction method based on a double-linear array CCD, which aims to improve the accuracy and efficiency of dilution instrument liquid preparation, enhance the stability and yield of the product in practical use, and reduce or even eliminate the problems of instrument damage and accidents caused by positioning errors, and provides the following technical scheme:
a dilution instrument space vision positioning deviation correction method based on a double linear array CCD comprises the following steps:
the method comprises the following steps: determining included angle lambda between optical axis and optical center connecting line of double-linear-array CCDlAnd λrThe influence on the visual positioning accuracy of the system is set, space points p and p (x, y and z) are set, and the included angle lambda of the connecting line of the optical axis and the optical center of the twin-line array CCD is determinedlAnd λrThe positioning deviation caused by the change, the double-line array CCD comprises a line array CCD1 and a line array CCD 2;
step two: determining the relation between the angle between the double-linear-array CCDs and the positioning deviation, constructing a vector synthesis function, and solving the partial derivative of the influence factors in the constructed vector synthesis function to obtain a partial derivative value;
step three: determining the relation between the distance between the double-linear-array CCDs and the positioning precision, and determining the relation between the distance between the double-linear-array CCDs and the positioning precision according to the space point p;
step four: and (4) carrying out coordinate correction on the visual positioning of the double-linear array CCD, and determining the corrected space three-dimensional coordinate of the sample bottle.
Preferably, the first step is specifically:
the first step is as follows: the spatial distribution of the linear CCD1 and the linear CCD2 determines the central axis of projection and the optical center o of the linear CCD1lAnd optical center o of linear CCD2rSetting a space point p, wherein the three-dimensional space coordinate of the space point p is p (x, y, z);
the second step is that: setting the projection of a space point p through the linear array CCD1 and the CCD2Direction resolved horizontal azimuth angle gammalAnd gammarAre all equal to the horizontal azimuth gamma of the projection direction;
the third step: according to gammalAnd gammarDetermining the angle theta of the vertical planes of the linear CCD1 and the CCD2lAnd thetarAccording to thetalAnd thetarDetermining the included angle lambda between the optical axes and the optical center of the twin-line array CCD1 and the CCD2lAnd λrVariation-induced positioning deviation, which is expressed by the following equation:
Figure BDA0002171454500000021
Figure BDA0002171454500000022
wherein the content of the first and second substances,
Figure BDA0002171454500000023
and
Figure BDA0002171454500000024
the positioning deviation, χ, of the CCD1 and the CCD2, respectivelyl,χrThe acting angles of the CCD1 and the CCD2 are the sum;
the fourth step: selecting the maximum value of the positioning deviation of the CCD1 and the CCD2 as a deviation value in the stereoscopic vision positioning process, and expressing the deviation value in the stereoscopic vision positioning process by the following formula:
Figure BDA0002171454500000025
wherein, DeltaλThe offset value in the stereoscopic vision positioning process.
Preferably, the second step is specifically:
the first step is as follows: determining the relation between the angle between the double-linear-array CCD and the positioning deviation, and decomposing the horizontal azimuth angle gamma through the projection direction of the space point p passing through the linear-array CCD1 and the linear-array CCD2lAnd gammar；
The second step is that: constructing a vector synthesis function, and solving the partial derivatives of the influence factors in the vector synthesis function to obtain partial derivatives;
the third step: horizontal azimuth angle gammalAnd gammarAnd if the deviation belongs to the correlation direction of the linear array CCD1 and the linear array CCD2, synthesizing and calculating the deviation value to obtain a horizontal deviation, and expressing the horizontal deviation by the following formula:
Figure BDA0002171454500000031
Figure BDA0002171454500000032
Figure BDA0002171454500000033
wherein, DeltaγIs horizontal deviation, f is focal length, xi is distance between the measured object and linear array CCD, γl，ΥrHorizontal deviation dominance factors of line CCD1 and CCD2, respectively.
Preferably, the third step is specifically:
the first step is as follows: determining the relation between the distance between the linear array CCD1 and the linear array CCD2 and the positioning accuracy, and enabling the horizontal azimuth angle gamma to be gamma when the space point p is at the intersection point of the linear array CCD1 and the image plane main shaft of the linear array CCD2lAnd gammarAre all equal to zero, λl＝λr＝λ，θl＝θr＝0，fl＝fr＝0，fl,frThe focal lengths of the linear CCD1 and the linear CCD2, respectively;
the second step is that: calculating the spatial coordinates of the spatial point p, which is expressed by the following formula:
Figure BDA0002171454500000034
Figure BDA0002171454500000035
Figure BDA0002171454500000036
wherein, Xl，XrThe horizontal pixel coordinates of the linear array CCD1 and the CCD2 respectively;
the third step: order to
Figure BDA0002171454500000041
Figure BDA0002171454500000042
Is the distance between line CCD1 and line CCD 2; simplified expressions (7) and (8), the simplified expressions (7) and (8) being represented by the following formulae:
Figure BDA0002171454500000043
Figure BDA0002171454500000044
the fourth step: order to
Figure BDA0002171454500000045
Calculating the resultant quantity of the distance between the linear CCD1 and the linear CCD2 to the positioning sheet difference, and expressing the positioning deviation resultant quantity by the following formula:
Figure BDA0002171454500000046
wherein, DeltaDisPositioning deviation composite quantity, namely delta X, delta Y and delta Z respectively represent the deviation between the positioning value and the true value of the space point p in the X, Y and Z directions;
preferably, the fourth step is specifically:
the first step is as follows: fixing the linear array CCD1 and the linear array CCD2, setting up a measuring coordinate system, and setting a reference coordinate P1(x1,z1)，P2(x2,z2) Ideal pixel coordinate u11And u21With offset actual pixel coordinates u'11And u'21Recording the deviation of the central pixel extraction as delta epsilon;
the second step is that: obtaining optical centers O 'of the linear array CCD1 and the linear array CCD2 by a visual positioning left calculation method'1、O′2By the projection direction
Figure BDA0002171454500000047
And linear array CCD scans the plane to obtain u1l，u2lRespectively is
Figure BDA0002171454500000048
And
Figure BDA0002171454500000049
then u'1lAnd u'2lRespectively is
Figure BDA00021714545000000410
And
Figure BDA00021714545000000411
then pass through u1lP′1Direction and u2lP′2Direction in turn
Figure BDA00021714545000000412
The third step: the coordinates of the image points of the space points p respectively scanned by the twin-line CCD array are ulAnd urAccording to the analysis of factors influencing the positioning precision, the real scanning position of P is known to be u'lAnd u'rDeriving u from geometric constraintslAnd urIn turn is
Figure BDA00021714545000000413
And
Figure BDA0002171454500000051
the fourth step: determining the overall positioning deviation Delta of a twin-line CCD arrayComU 'then'rIs that
Figure BDA0002171454500000052
Then O'l、O′rIs at a distance of
Figure BDA0002171454500000053
Calculating equivalent distance of double linear array CCD caused by position visual angle
Figure BDA0002171454500000054
The equivalent distance of the double-linear array CCD caused by the position visual angle is expressed by the following formula
Figure BDA0002171454500000055
Figure BDA0002171454500000056
The fifth step: giving out the corrected three-dimensional coordinate of the space point p by combining the stereoscopic vision positioning
Figure BDA0002171454500000057
The corrected three-dimensional coordinates are represented by:
Figure BDA0002171454500000058
wherein the content of the first and second substances,
Figure BDA0002171454500000059
respectively a three-dimensional coordinate point of the corrected space point p;
substituting equation (13) into equation (14), the corrected three-dimensional coordinates are represented by the following equation:
Figure BDA00021714545000000510
the invention has the following beneficial effects:
the method can realize the high-precision positioning of the linear array CCD with common performance on the spatial position distribution of all the sample bottles on the dilution instrument platform body, and then transmits the sample bottle position distribution information to the motion control unit of the dilution instrument, so that the system can accurately, quickly and flexibly complete the corresponding dilution task. The rapidity effect achieved by the invention is embodied in that the positioning system provides global spatial distribution of the sample bottles, and the execution unit can accelerate to directly reach the position of the task bottle instead of the traditional detection and uniform-speed forward; the flexibility effect achieved by the invention is embodied in that through the reconstructed sample bottle space three-dimensional coordinates, an operator can directly place the sample bottle at any position on the system table body instead of some limited serial numbers and fixed positions. In general, the linear array CCD with the lowest performance is selected, the positioning deviation is reduced through the optimization of the spatial position distribution of the linear array CCD, the three-dimensional positioning precision of the system is improved, the overall development cost of the dilution instrument system is further reduced, and the method has good universality and expandability.
Drawings
FIG. 1 is a diagram of a diluter and an attached twin-line CCD array;
FIG. 2 is a two-line array CCD spatial position distribution and imaging model;
FIG. 3 is λl,λrThe law of action of the angle on the deviation;
FIG. 4 is γl,γrThe law of action of the angle on the deviation;
FIG. 5 is a drawing showing
Figure BDA0002171454500000061
The law of action on the deviation;
FIG. 6 is a diagram showing the influence of attitude angle on the deviation under a certain linear array CCD spacing;
FIG. 7 is a schematic view of a visual alignment offset correction;
FIG. 8 is a distribution of peak correlation for feature matching;
FIG. 9 is a graph of the effect of sample vial registration in a dilutor system;
FIG. 10 is a reconstructed map of the spatial location coordinates of the sample vial of the dilutor.
Detailed Description
The present invention will be described in detail with reference to specific examples.
The first embodiment is as follows:
according to the flow chart shown in fig. 1, the invention provides a dilution instrument space vision positioning deviation correction method based on a double linear array CCD, which comprises the following steps:
the method comprises the following steps: determining included angle lambda between optical axis and optical center connecting line of double-linear-array CCDlAnd λrThe influence on the visual positioning accuracy of the system is set, space points p and p (x, y and z) are set, and the included angle lambda of the connecting line of the optical axis and the optical center of the twin-line array CCD is determinedlAnd λrThe positioning deviation caused by the change, the double-line array CCD comprises a line array CCD1 and a line array CCD 2;
step two: determining the relation between the angle between the double-linear-array CCDs and the positioning deviation, constructing a vector synthesis function, and solving the partial derivative of the influence factors in the constructed vector synthesis function to obtain a partial derivative value;
step three: determining the relation between the distance between the double-linear-array CCDs and the positioning precision, and determining the relation between the distance between the double-linear-array CCDs and the positioning precision according to the space point p;
step four: and (4) carrying out coordinate correction on the visual positioning of the double-linear array CCD, and determining the corrected space three-dimensional coordinate of the sample bottle.
Step 1: discussion determination of included angle lambda between linear array CCD optical axis and optical center connecting linel,λrInfluence on the visual positioning accuracy of the system and give quantitative description relational expressions. The spatial distribution of the line CCD1 and the line CCD2 determines the central projection axis and the central projection axis olorBy the angle of (a), thus λl,λrThe change in (b) affects the variation in the deviation. Let γ be for classification discussion herel＝γrThe total spatial deviation Δ in the y, x, y, z directions is at the same time dependent on the angular position θ with respect to the vertical planel,θrIs changed by a change ofl,λrThe variation-induced positioning deviation can be expressed as:
Figure BDA0002171454500000071
Figure BDA0002171454500000072
the horizontal azimuth angle gamma of the space point P is resolved through the projection directions of the two linear array CCDsl,γr
Middle X typel＝γl+λl，χr＝γr+λrThe maximum value can be taken as a deviation value in the stereoscopic vision positioning process:
Figure BDA0002171454500000073
step 2: and analyzing the relation between the angle between the double-linear-array CCDs and the positioning deviation. The horizontal azimuth angle gamma of the space point P is resolved through the projection directions of the two linear array CCDsl,γrThe magnitude of (c) also affects the variance of the deviation. By solving the deviation of each influence factor in the constructed vector synthesis function, and because the horizontal azimuth belongs to the correlation direction of the twin-line array CCD, the deviation can be synthesized as follows:
Figure BDA0002171454500000074
wherein
Figure BDA0002171454500000075
Figure BDA0002171454500000076
And step 3: and analyzing the relation between the distance between the double-linear-array CCDs and the positioning precision. The distance between the linear array CCDs has great influence on the positioning accuracy, and for the convenience of analysis, a space point p (x, y, z) is assumed to be at the intersection point of the main axes of the two CCD image planes, so that lambda is setl＝λr＝λ，γl＝γr＝0，θl＝θr＝0，fl＝f r0. Since the effect of CCD distance on deviation is reflected in the horizontal plane direction, there are
Figure BDA0002171454500000081
Then, from the coordinates of the spatial point p, one can find:
Figure BDA0002171454500000082
Figure BDA0002171454500000083
step 31: order to
Figure BDA0002171454500000084
The formulae (5) and (6) can be further simplified to
Figure BDA0002171454500000085
Figure BDA0002171454500000086
Step 32: note the book
Figure BDA0002171454500000087
The effect of the twin line CCD spacing on the skew can then be quantified as:
Figure BDA0002171454500000088
and 4, step 4: and according to the analysis, performing coordinate correction on the visual positioning based on the linear array CCD.
Step 41: after the linear array CCD is fixed, a measuring coordinate system is set, wherein P is1(x1,z1)，P2(x2,z2) Is the reference point coordinate, u11，u21Is an ideal pixel coordinate, u'11，u′21Is the actual pixel coordinate with the deviation, noting that the deviation of the center point pixel extraction is Δ ε.
Step 42: linear array CCD optical center O 'can be obtained through visual positioning coordinate calculation principle'1、O′2Coordinates; by throwingShadow direction
Figure BDA0002171454500000089
And linear array CCD scans the plane to obtain u1l，u2lRespectively is
Figure BDA00021714545000000810
And
Figure BDA00021714545000000811
then u'1lAnd u'2lRespectively is
Figure BDA00021714545000000812
And
Figure BDA00021714545000000813
then pass through u1lP′1Direction and u2lP′2Direction in turn
Figure BDA0002171454500000091
Step 43: setting P as the central coordinate of some sample bottle on the platform and the coordinate of the image point scanned by the double-linear array CCD as ulAnd urFrom the analysis of the factors affecting the positioning accuracy, the actual scanning position of P is u'lAnd u'r. Also, u is derived from geometric constraintslAnd urIn turn is
Figure BDA0002171454500000092
And
Figure BDA0002171454500000093
step 44: positioning deviation delta of linear array CCD (Charge coupled device) overallComU 'then'rIs that
Figure BDA0002171454500000094
Then O'l、O′rIs at a distance of
Figure BDA0002171454500000095
The equivalent distance of the double linear array CCD caused by the position visual angle
Figure BDA0002171454500000096
Is that
Figure BDA0002171454500000097
Step 45: the three-dimensional coordinate of the sample bottle space is given by combining the three-dimensional visual positioning principle
Figure BDA0002171454500000098
The correction formula of (1):
Figure BDA0002171454500000099
step 45: the three-dimensional coordinate of the sample bottle space is given by combining the three-dimensional visual positioning principle
Figure BDA00021714545000000910
The correction formula of (1):
Figure BDA00021714545000000911
the invention realizes the high-precision positioning function of the linear array CCD with common performance by comprehensively analyzing the factors influencing the visual positioning error, searching the association influence rule and optimizing the spatial position adjustment. The method comprises the steps of firstly analyzing the influence of linear array CCD space position distribution on the accuracy of visual positioning, establishing an optimal vector function relational expression by considering the correlation action rule among deviation influence factors, searching the total deviation change rule under the simultaneous action of all the factors through Taylor series expansion, and determining the space pose distribution among the linear array CCDs through the rule to enable the linear array CCDs to reach an optimal positioning structure state.
The second embodiment is as follows:
step 1: stereo visionThe two linear CCD space distribution and imaging model in the sensory localization are shown in figure 2, Ol-XlYlAnd Or-XrYrRespectively, the scanning imaging surface coordinate systems of the linear CCD1 and the linear CCD 2; olAnd orThe distance between the optical centers can be regarded as the physical distance of the linear array CCD; f. ofl,frRespectively the focal lengths of the two linear array CCDs; the vertical distance between the sample bottle and the two-linear array CCD is xi; according to the principle of pinhole imaging, the center point P (x, y, z) of the sample cap is along the optical axis OlolAnd OrorThe projection coordinates on the image planes of the linear array CCD1 and the linear array CCD2 are p respectivelyl(Ul,Vl)，pr(Ur,Vr). And enabling the system measurement coordinate system to coincide with the left linear array CCD coordinate system. O islolAnd OrorLine o connecting the optical centerlorThe included angle between them is marked as (α)l,αr) (ii) a And decomposing the P point through the projection of the two linear array CCDs: horizontal azimuth angle gammal,γrAnd a vertical azimuth angle thetal,θr. If P' is the projected point of P along the horizontal direction, then pass through Δ olorP' may establish the following geometric relationship:
Figure BDA0002171454500000101
Figure BDA0002171454500000102
step 11: in the same way at Δ PP' olIn (b), one can obtain:
Figure BDA0002171454500000103
by the triangulation principle, the spatial coordinates of point P can be solved:
Figure BDA0002171454500000104
in the formula, tan gammal＝Xl/fl，tanγr＝Xr/fr，tanθl＝Y1·cosγl/fl，tanθr＝Y2·cosγr/fr
Step 2: by analyzing all spatial position distribution factors which can influence positioning deviation in a diluter vision positioning system, and in addition, the parameters interact and are mutually associated, the following vector synthesis function is constructed:
p(x,y,z)＝CF(Ul,Ur,Vl,Vr,λl,λr,γl,γr,Ξ) (15)
by solving the partial derivatives of the variables in the three directions of x, y and z, expanding the Taylor series and taking the first order, the direction deviations are respectively expressed as:
Figure BDA0002171454500000111
according to the deviation distribution and multi-deviation synthesis principle, the total deviation of the visual positioning of the sample bottle is the sum of the measurement deviations of the space coordinates in the x, y and z directions:
Figure BDA0002171454500000112
in which i is the parameter U in the synthesis functionl,Ur,Vl,Vr,λl,λr,γl,γrXi j are three different component directions.
And step 3: let gamma bel＝γrThe total spatial deviation Δ in the y, x, y, z directions is at the same time dependent on the angular position θ with respect to the vertical planel,θrIs changed by unfolding the partial derivative according to the formula (16) and then carrying the partial derivative into the formula (14), lambdal,λrThe variation-induced positioning deviation can be expressed as:
Figure BDA0002171454500000113
Figure BDA0002171454500000114
middle X typel＝γl+λl，χr＝γr+λr。
Step 31 is due to two included angles λl,λrThe accuracy of the internal parameters and pose parameters of the left linear array CCD and the right linear array CCD are respectively influenced, the rotation and translation conversion under different coordinate systems is a non-deviation transfer process, and then the maximum value can be taken as a deviation value in the visual positioning process:
Figure BDA0002171454500000121
step 32: by plotting equations (18) - (19) using MATLAB, we can more intuitively see the angle λ as shown in FIG. 3l,λrAnd (4) influence rule on deviation.
And 4, step 4: influence factor gamma is influenced by the formula (15)l,γrPerforming partial derivation:
Figure BDA0002171454500000122
Figure BDA0002171454500000123
wherein the content of the first and second substances,
Figure BDA0002171454500000124
step 41: because the horizontal azimuth belongs to the correlation direction of the twin-line array CCD, the deviation is synthesized to obtain:
Figure BDA0002171454500000125
wherein
Figure BDA0002171454500000126
Figure BDA0002171454500000127
Step 42: by plotting equation (23) by MATLAB, we can more intuitively see the angle γ as shown in FIG. 4l,γrAnd (4) influence rule on deviation.
And 5: let λ be the intersection of the principal axes of the two CCD image planes at the assumed spatial point p (x, y, z)l＝λr＝λ，γl＝γr＝0，θl＝θr＝0，fl＝f r0. Since the effect of the CCD distance on the deviation is reflected in the horizontal plane direction, the value in the y-direction is 0, i.e.
Figure BDA0002171454500000128
Then, from the coordinates of the spatial point p, one can find:
Figure BDA0002171454500000131
Figure BDA0002171454500000132
step 51: order to
Figure BDA0002171454500000133
The formulae (24) and (25) can be further simplified to
Figure BDA0002171454500000134
Step 52: note the book
Figure BDA0002171454500000135
The effect of the twin line CCD spacing on the skew can then be quantified as:
Figure BDA0002171454500000136
step 53: by plotting equation (27) through MATLAB, as shown in FIG. 5, we can more intuitively see that
Figure BDA0002171454500000137
And (4) influence rule on deviation.
Step 6: the influence of the spatial position distribution of the double-linear-array CCD on the positioning deviation is obtained, and the method comprises the following three parts: deltaλ，Δγ，ΔDisThe variation of the deviation of the three parts is correlated, in order to obtain the final total deviation, a vector synthesis function CF (U) is determined according to the deviation distribution in FIG. 6 by controlling the ratio ξ of the CCD spacing to the measured depth distance to be constant and then drawing the variation rule of the total deviation along with the influencing factors by MATLAB, as shown in FIG. 6l,Ur,Vl,Vr,λl,λr,γl,γrXi) of the influencing parameter.
The following is to correct the original space point coordinate solving formula, as shown in fig. 7, to set the X and Z directions of the measurement coordinate system O-XYZ and the O of the left linear array CCD coordinate systemlZlr，OlZlThe directions coincide. The optical center position of the left and right linear array CCD can be recorded as Ol(0,0,0)，
Figure BDA0002171454500000138
CCD scanning image plane FlAnd FrAre all located on Z ═ f.
And 7: if P isw(xw,yw,zw) The corresponding image coordinate is (x)l,yl) And (x)r,yr) Then, according to the principle of stereo vision localization, it can obtain:
Figure BDA0002171454500000141
step 71: fixing the space position of linear array CCD, and setting P in the coordinate system diagram1(x1,z1)，P2(x2,z2) Is the reference point coordinate, u1l，u2lIs an ideal pixel coordinate, u'1l，u′2lIs the actual pixel coordinate with the deviation, noting that the deviation of the center point pixel extraction is Δ ε. Linear array CCD optical center O 'can be obtained through visual positioning coordinate calculation principle'1、O′2Coordinates; by projection direction
Figure BDA0002171454500000142
And linear array CCD scans the plane to obtain u1l，u2lRespectively is
Figure BDA0002171454500000143
And
Figure BDA0002171454500000144
then u'1lAnd u'2lRespectively is
Figure BDA0002171454500000145
And
Figure BDA0002171454500000146
then pass through u1lP′1Direction and u2lP′2Direction in turn
Figure BDA0002171454500000147
Step 72: setting P as the central coordinate of some sample bottle on the platform and the coordinate of the image point scanned by the double-linear array CCD as ulAnd urFrom the analysis of the factors affecting the positioning accuracy, the actual scanning position of P is u'lAnd u'r. Also, u is derived from geometric constraintslAnd urIn turn is
Figure BDA0002171454500000148
And
Figure BDA0002171454500000149
the positioning deviation Delta of the linear array CCD is obtainedComU 'then'rIs that
Figure BDA00021714545000001410
Then O'l、O′rIs at a distance of
Figure BDA00021714545000001411
The equivalent distance of the double linear array CCD caused by the position visual angle
Figure BDA00021714545000001412
Is that
Figure BDA00021714545000001413
Corrected space three-dimensional coordinate of sample bottle
Figure BDA00021714545000001414
Can be expressed as:
Figure BDA0002171454500000151
the results of the performance tests are as follows: in FIG. 3, γ is setl＝γr＝5°，θl＝θrAt 30 °, it can be seen that (λ)l,λr)[30 60]Time, deviation ΔλThe whole value is small and can be stabilized below 1 mm. If λ of two CCDs is maintainedl,λrThe angles are all equal, then the deviation ΔλWill tend to be smaller because the entire plane of deviation is distributed concavely, and therefore the optimum position parameter λ is selectedl＝λ r30 ° is set. From FIG. 4, λ is setl＝λr＝40°，θl＝θ r30 deg. in (gamma)l,γr)[40 40]Then, the deviation Δ can be seenγIn a distribution pattern with four corners larger and a middle area smaller when the gamma is largerl,γrOver 20 deg., deviation deltaγWill increase rapidly; when gamma isl,γrAll around 0 DEG, deviation DeltaγAt a minimum, this is also consistent with experimental experience: the smaller the field of view, theThe higher the resolution, the higher the positioning accuracy is consistent. In fig. 5, the set condition is λl＝λr＝60°，γl＝γrThe distance between the measured object and the linear CCD is kept constant at 20 degrees, and the delta is increased along with the increase of the distance between the CCDs, namely ξ is increasedDisDecreases rapidly, when ξ e (1,2), the deviation deltaDisThe variation tends to be stable, when ξ > 2, deltaDisIt becomes rapidly larger, so if ξ is not in the (1,2) range, it is necessary to adjust the spatial position distribution memorability of the twin-line array CCD to reduce the deviation deltaDis。
In summary, based on the coupling effect of the parameter influencing the deviation shown in FIG. 6, a set of optimal parameter values, λ, can be selectedl＝λr＝30°，γl＝γr＝5°，Ξ＝7500mm，
Figure BDA0002171454500000152
The image subpixel extraction accuracy Δ ∈ was 0.01pixel, and the positions of 10 vials on the dilution instrument platform were visually positioned, and the obtained positioning deviations are shown in table 1.
TABLE 1 optimized positioning result of double linear array CCD space position distribution
Figure BDA0002171454500000153
Figure BDA0002171454500000161
In this embodiment, we select a low performance linear array CCD with a resolution of 685 pixels and a pixel size dx＝dyThe focal length can be adjusted within 20-35mm under the condition of 8 um. By adopting the device, high positioning accuracy is obtained, the corrected positioning accuracy can be controlled within the range of 0.01mm, a high-performance CCD (charge coupled device) with high manufacturing cost is not required, and the device cost is greatly reduced.
In addition, by optimizing the spatial position distribution of the linear array CCD, a basic matrix between the CCDs can be obtained more accurately, so that the characteristic matching operation peak is obvious, and the point characteristic matching precision of different CCD imaging is improved according to the characteristic matching correlation peak distribution condition shown in FIG. 8. And then extracting the characteristics of the sample bottle on the dilution instrument platform, and performing three-dimensional registration to obtain a registration effect diagram of the sample bottle of the dilution instrument system shown in fig. 9, wherein the matching accuracy is 100%. And finally, the high-precision reconstruction of the space position of the sample bottle can be completed, the effect is shown in fig. 10, so that the sample bottle does not need to be placed according to a certain rule, the visual positioning system can directly realize the positioning of the sample bottle, and the flexibility of the system is enhanced.
The above description is only a preferred embodiment of the dilution instrument spatial visual positioning deviation correction method based on the twin-line CCD, and the protection scope of the dilution instrument spatial visual positioning deviation correction method based on the twin-line CCD is not limited to the above embodiments, and all technical solutions belonging to the idea belong to the protection scope of the present invention. It should be noted that modifications and variations which do not depart from the gist of the invention will be those skilled in the art to which the invention pertains and which are intended to be within the scope of the invention.

Claims (4)

1. A dilution instrument space vision positioning deviation correction method based on a double linear array CCD is characterized by comprising the following steps: the method comprises the following steps:
the method comprises the following steps: determining included angle lambda between optical axis and optical center connecting line of double-linear-array CCDlAnd λrThe influence on the visual positioning accuracy of the system is set, space points p and p (x, y and z) are set, and the included angle lambda of the connecting line of the optical axis and the optical center of the twin-line array CCD is determinedlAnd λrThe positioning deviation caused by the change, the double-line array CCD comprises a line array CCD1 and a line array CCD 2;
step two: determining the relationship between the angle and the positioning deviation between the double-linear-array CCDs, constructing a vector synthesis function, solving the partial derivatives of the influence factors in the constructed vector synthesis function, and respectively representing the directional deviation as follows by solving the partial derivatives of the variables in the three directions of x, y and z, expanding the Taylor series and taking the first-order series:
Figure FDA0002381864990000011
obtaining a partial derivative value;
step three: determining the relation between the distance between the double-linear-array CCDs and the positioning precision, and determining the relation between the distance between the double-linear-array CCDs and the positioning precision according to the space point p;
the third step is specifically as follows:
the first step is as follows: determining the relation between the distance between the linear array CCD1 and the linear array CCD2 and the positioning accuracy, and enabling the horizontal azimuth angle gamma to be gamma when the space point p is at the intersection point of the linear array CCD1 and the image plane main shaft of the linear array CCD2lAnd gammarAre all equal to zero, λl＝λr＝λ，
Figure FDA0002381864990000013
fl＝fr＝0，fl,frThe focal lengths of the linear CCD1 and the linear CCD2, respectively;
the second step is that: calculating the spatial coordinates of the spatial point p, which is expressed by the following formula:
Figure FDA0002381864990000012
Figure FDA0002381864990000021
Figure FDA0002381864990000022
wherein, Xl，XrThe horizontal pixel coordinates of the linear array CCD1 and the CCD2 respectively;
the third step: order to
Figure FDA0002381864990000027
Figure FDA0002381864990000028
Is the distance between line CCD1 and line CCD 2; simplified expressions (7) and (8) are represented by the following formulasFormulae (7) and (8):
Figure FDA0002381864990000023
Figure FDA0002381864990000024
the fourth step: order to
Figure FDA0002381864990000025
Calculating the resultant quantity of the distance between the linear CCD1 and the linear CCD2 to the positioning sheet difference, and expressing the positioning deviation resultant quantity by the following formula:
Figure FDA0002381864990000026
wherein, DeltaDisPositioning deviation composite quantity, namely delta X, delta Y and delta Z respectively represent the deviation between the positioning value and the true value of the space point p in the X, Y and Z directions;
step four: and (4) carrying out coordinate correction on the visual positioning of the double-linear array CCD, and determining the corrected space three-dimensional coordinate of the sample bottle.
2. The method for correcting the spatial visual positioning deviation of the dilution instrument based on the double-linear-array CCD as claimed in claim 1, wherein: the first step is specifically as follows:
the first step is as follows: the spatial distribution of the linear CCD1 and the linear CCD2 determines the central axis of projection and the optical center o of the linear CCD1lAnd optical center o of linear CCD2rSetting a space point p, wherein the three-dimensional space coordinate of the space point p is p (x, y, z);
the second step is that: setting a horizontal azimuth angle gamma resolved by a space point p through the projection directions of the linear array CCD1 and the CCD2lAnd gammarAre all equal to the horizontal azimuth gamma of the projection direction;
the third step: according to gammalAnd gammarDetermining the angle theta of the vertical planes of the linear CCD1 and the CCD2lAnd thetarAccording to thetalAnd thetarDetermining the included angle lambda between the optical axes and the optical center of the twin-line array CCD1 and the CCD2lAnd λrVariation-induced positioning deviation, which is expressed by the following equation:
Figure FDA0002381864990000031
Figure FDA0002381864990000032
wherein the content of the first and second substances,
Figure FDA0002381864990000033
and
Figure FDA0002381864990000034
the positioning deviation, χ, of the CCD1 and the CCD2, respectivelyl,χrThe acting angles of the CCD1 and the CCD2 are the sum;
the fourth step: selecting the maximum value of the positioning deviation of the CCD1 and the CCD2 as a deviation value in the stereoscopic vision positioning process, and expressing the deviation value in the stereoscopic vision positioning process by the following formula:
Figure FDA0002381864990000035
wherein, DeltaλThe offset value in the stereoscopic vision positioning process.
3. The method for correcting the spatial visual positioning deviation of the dilution instrument based on the double-linear-array CCD as claimed in claim 1, wherein: the second step is specifically as follows:
the first step is as follows: determining the relation between the angle between the double-linear-array CCD and the positioning deviation, and decomposing the horizontal azimuth angle gamma through the projection direction of the space point p passing through the linear-array CCD1 and the linear-array CCD2lAnd gammar；
The second step is that: constructing a vector synthesis function, and solving the partial derivatives of the influence factors in the vector synthesis function to obtain partial derivatives;
the third step: horizontal azimuth angle gammalAnd gammarAnd if the deviation belongs to the correlation direction of the linear array CCD1 and the linear array CCD2, synthesizing and calculating the deviation value to obtain a horizontal deviation, and expressing the horizontal deviation by the following formula:
Figure FDA0002381864990000036
Figure FDA0002381864990000037
Figure FDA0002381864990000038
wherein, DeltaγIs horizontal deviation, f is focal length, xi is distance between the measured object and linear array CCD, γl，ΥrHorizontal deviation dominance factors of line CCD1 and CCD2, respectively.
4. The method for correcting the spatial visual positioning deviation of the dilution instrument based on the double-linear-array CCD as claimed in claim 1, wherein: the fourth step is specifically as follows:
the first step is as follows: fixing the linear array CCD1 and the linear array CCD2, setting up a measuring coordinate system, and setting a reference coordinate P1(x1,z1)，P2(x2,z2) Ideal pixel coordinate u11And u21With offset actual pixel coordinates u'11And u'21Recording the deviation of the central pixel extraction as delta epsilon;
the second step is that: obtaining optical centers O 'of the linear array CCD1 and the linear array CCD2 by a visual positioning left calculation method'1、O′2By the projection direction
Figure FDA0002381864990000041
And linear array CCD scans the plane to obtain u1l，u2lRespectively is
Figure FDA0002381864990000042
And
Figure FDA0002381864990000043
then u'1lAnd u'2lRespectively is
Figure FDA0002381864990000044
And
Figure FDA0002381864990000045
then pass through u1lP′1Direction and u2lP′2Direction in turn
Figure FDA0002381864990000046
The third step: the coordinates of the image points of the space points p respectively scanned by the twin-line CCD array are ulAnd urAccording to the analysis of factors influencing the positioning precision, the real scanning position of P is known to be u'lAnd u'rDeriving u from geometric constraintslAnd urIn turn is
Figure FDA0002381864990000047
And
Figure FDA0002381864990000048
the fourth step: determining the overall positioning deviation Delta of a twin-line CCD arrayComU 'then'rIs that
Figure FDA0002381864990000049
Then Ol′、OrAt a distance of
Figure FDA00023818649900000410
Calculating equivalent distance of double linear array CCD caused by position visual angle
Figure FDA00023818649900000413
The equivalent distance of the double-linear array CCD caused by the position visual angle is expressed by the following formula
Figure FDA00023818649900000414
Figure FDA00023818649900000411
The fifth step: giving out the corrected three-dimensional coordinate of the space point p by combining the stereoscopic vision positioning
Figure FDA00023818649900000412
The corrected three-dimensional coordinates are represented by:
Figure FDA0002381864990000051
wherein the content of the first and second substances,
Figure FDA0002381864990000052
respectively a three-dimensional coordinate point of the corrected space point p;
substituting equation (13) into equation (14), the corrected three-dimensional coordinates are represented by the following equation:
Figure FDA0002381864990000053
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