CN102116606B - Method and device for measuring axial displacement by taking one-dimensional three-primary-color peak valley as characteristic - Google Patents

Abstract

The invention relates to a method and a device for measuring axial displacement by taking one-dimensional three-primary-color peak valley as characteristic. The device consists of a common computer and a camera of the common computer, a stepping motor and an interface circuit of the stepping motor as well as a camera axial displacement device. The camera is arranged on the camera axial displacement device by taking a high-precision micromovement stepping motor as a core, the stepping motor is connected to an RS232C interface of the computer through the interface circuit of the stepping motor, and the computer is provided with a camera shooting and an axial displacement measuring program according to one-dimensional three-primary-color peak valley data. An optimal viewing area can be automatically analyzed and selected by computing autocorrelation coefficient; the rotation of the stepping motor can be controlled by the RS232C interface of the computer, so as to control the camera to move forwards or backwards; by analyzing and measuring the quantity of peaks and valleys of three primary colors of an image frame along one coordinate axes direction, the position where the peaks and valleys are the most is used as the optimal imaging and focusing position, so as to obtain axial relative displacement. The measuring method is novel and can adapt to environment illumination change to a certain degree, and the measuring speed is higher.

Description

With one dimension three primary colours peak valley is the method and the device of pattern measurement axial displacement

Technical field

The invention belongs to the digital picture field of measuring technique, the camera Measuring Object that particularly uses a computer is along the method and the device thereof of the micro-displacement of its optic axis direction generation.

Background technology

The application for a patent for invention of submitting to recently " is method and the device of pattern measurement along the displacement of optical axis direction with the three primary colours peak valley " has proposed a kind of photosensor arrays of the camera that uses a computer and has surveyed along the method for the micro-displacement of optic axis direction generation, and it has made full use of the information that photosensor arrays reflected of computing machine camera.But, its computing workload is more.

Summary of the invention

It is the method and the device of pattern measurement axial displacement with one dimension three primary colours peak valley that the present invention provides a kind of; It utilizes the computing machine camera; Can take place in the environment of certain variation at illuminating position, Measuring Object is along the micro-displacement vector that optical axis direction took place of camera.

The technical solution adopted for the present invention to solve the technical problems is: computing machine camera of computer configuration that a Daepori is logical; It is on the axial displacement device formed of core by the high-precision micro displacement stepper motor that this camera is installed in one; This stepper motor is connected to the RS232C interface of said computing machine through the stepper motor interface circuit; Said computer configuration has camera to take and according to one dimension three primary colours peak valley DATA REASONING axial displacement program; It is the method for the pattern measurement axial displacement of picture frame that this program has embodied with the three primary colours peak valley, comprising:

Step 1, with the form of bitmap (M * N, M, N ∈ positive integer), take the image of a frame testee, as a reference frame; First locations of pixels with this frame pel array upper left corner is an initial point, is the x direction of principal axis with to the right direction, and vertical downward direction is the y direction of principal axis, and the unit of the coordinate system of getting is the size of a pixel; Choose a zone at the middle section of said pel array, size is m ₀* n ₀, m ₀, n ₀The ∈ positive integer is referred to as view window, and the horizontal direction of the said pel array of its distance and the edge pixel of vertical direction respectively have h and v pixel, promptly have: m ₀+ 2h=M, n ₀+ 2v=N, h, v ∈ positive integer;

Step 2, for the pel array of above-mentioned reference frame; By pixel column, by the edge direction data of pixel column derivation along X-direction and Y direction; And with the binary numeral 001 of 3bit; 010 and 100 wherein positive limit, marginal and the 3rd type of limits of expression respectively, so constituted corresponding said reference frame pel array about X-direction with about two frame edge direction data { reference of Y direction _x(x, y) } and { reference _y(x, y) }, wherein, subscript x or y represent the direction of the coordinate axis on institute edge respectively, all pixels in the change in coordinate axis direction view window that wherein the function subscript is indicated of symbol " { } " expression edge (x, these data are preserved in a set of the edge direction data of y) locating;

Step 3, for above-mentioned two frame edge direction data, calculate the auto correlation matching factor of view window interior pixel array in the said reference frame respectively:

$\mathrm{auto}\_\mathrm{correlatio}{n}_x(a,b)=\underset{y=v+1}{\overset{v+1+n0}{\mathrm{\Σ}}}\underset{x=h+1}{\overset{h+1+m0}{\mathrm{\Σ}}}[{\mathrm{reference}}_x(x,y)\·{\mathrm{reference}}_x(x+a,y+b)]$

$\mathrm{auto}\_\mathrm{correlatio}{n}_y(a,b)=\underset{y=v+1}{\overset{v+1+n0}{\mathrm{\Σ}}}\underset{x=h+1}{\overset{h+1+m0}{\mathrm{\Σ}}}[{\mathrm{reference}}_y(x,y)\·{\mathrm{reference}}_y(x+a,y+b)]$

In the formula, sign of operation is represented binary logic and computing, its operation result or be logical zero or for logical one, the pairing numerical value of value of logical operation function is wherein got in sign of operation " [] " expression; Or be numerical value 0, or be numerical value 1, parametric variable a, the combination of b has determined the scale of associated match operator array; If get 3 * 3 associated match operator arrays: a=-1,0,1, b=-1; 0,1, therefore, each will produce 9 auto correlation coefficient auto_correlation along each change in coordinate axis direction _x(a, b) and auto_correlation _y(a, b);

Step 4, the auto correlation matching factor corresponding according to above-mentioned two frame edge direction data, search for respectively and under present body surface situation and illuminating position, can carry out matching ratio optimal viewing window pel array:

m _x＝m ₀±step，n _x＝n ₀±step，2h＝M-m _x，2v＝N-n _x

And m _y=m ₀± step, n _y=n ₀± step, 2h=M-m _y, 2v=N-n _y,

In the formula, subscript x, y represent respectively its value corresponding along X-direction and Y direction, step is the stepped parameter in the search procedure, the unlike signs of its front is determined by the direction of search; Get in this two class value big person and measure the scale of used view window array: m * n for this;

Step 5, for the pel array of above-mentioned reference frame, according to the data of its redness, green and blue component, derive line by line along the redness of X-direction, green and edge direction data blueness, one has 3 * 1=3 frame edge direction data;

According to the edge direction data of above-mentioned three kinds of primary colours, derive along the limit reflection condition of three kinds of primary colours of X-direction, have 3 * 1=3 frame limit reflection condition; For view window zone wherein, use the number of their pairing peaks of accumulator count, paddy: N respectively _{RX axle peak}And N _{RX axle paddy}, N _{GX axle peak}And N _{GX axle paddy}, N _{BX axle peak}And N _{BX axle paddy}, wherein, N (umber) representes number, R, G, B represent red, green and blue respectively; Add up above-mentioned totalizer count results and preserve it, be expressed as: N (i, j=0, forw=0, back=0), wherein; I=1,2,3...... representes the sequential counting of captured reference frame, also is the counting of measuring, j=0,1; 2,3 ..., the counting of the sampling frame of representing to take in the i time measuring process, variable forw (=0,1; 2 ...) and back (=0,1,2 ...) represent that respectively stepper motor generation clockwise described in the i time measurement rotates and the pairing step-by-step impulse counting of anticlockwise rotation; Before this measures beginning, have: i=1, j=0, forw=0, back=0;

Step 6, measurement beginning: said computing machine is exported forw=1 digital pulse signal to said stepper motor interface circuit through an output control line FORWARD of its RS232C interface; Control this stepper motor clockwise and rotate a step; Then, take j=1 frame sample framing bit figure;

For the pel array of above-mentioned sampling frame, according to the data of its redness, green and blue component, derive line by line along the redness of X-direction, green and edge direction data blueness, have 3 * 1=3 frame edge direction data;

According to the edge direction data of above-mentioned three kinds of primary colours, derive along the limit reflection condition of three kinds of primary colours of X-direction, have 3 * 1=3 frame limit reflection condition; For view window zone wherein, use the number of their pairing peaks of accumulator count, paddy: N respectively _{RX axle peak}And N _{RX axle paddy}, N _{GX axle peak}And N _{GX axle paddy}, N _{BX axle peak}And N _{BX axle paddy}Add up above-mentioned totalizer count results and preserve it, be expressed as: N (i, j=1, forw=1, back=0);

If step 7: N (i, j=1, forw=1, back=0)>=N (i, j=0; Forw=0, back=0), the output control line FORWARD of said computing machine through its RS232C interface export forw (=2,3 ...) individual digital pulse signal is to said stepper motor interface circuit; It is progressive to control the rotation of this stepper motor clockwise, each one step of clockwise rotation all take and analyze respectively take a sample before and after the comparison in the frame in the view window along all peaks of three kinds of primary colours of X-direction and the number sum N of paddy (i, j=forw-1, forw-1, back=0) and N (i; J=forw, forw back=0), preserves it, should have in this process: N (i; J=forw, forw, back=0)>=N (i, j=forw-1, forw-1; Back=0), up to satisfying: N (i, j=forw, forw, back=0)＜N (i; J=forw-1, forw-1, back=0), and at this moment, record (forw) _MAX=forw; Simultaneously; Said computing machine arrives said stepper motor interface circuit through another root output control line BACKWARD digital pulse signal of output (back=1) of its RS232C interface, controls anticlockwise one step of rotation of this stepper motor, at this moment; This measures the preceding initial position of beginning relatively, and the camera of this device promptly is in the best object image-forming focal position in this measurement: FocusP=(forw) _MAX-back=(forw) _MAX-1, its result calculated is more than or equal to 0, and the sense of rotation of representing said stepper motor is clockwise, in the corresponding sampling frame view window of this focal position along all peaks of three kinds of primary colours of X-direction and the number sum of paddy is: N (i, j=(forw) _MAX-1, forw=(forw) _MAX-1, back=0), the tale result of the sampling frame of taking in the measuring process is: j=(forw) _MAX+ back=(forw) _MAX+ 1;

If: N (i, j=1, forw=1, back=0)＜N (i, j=0; Forw=0, back=0), said computing machine is exported back=1 digital pulse signal to said stepper motor interface circuit through an output control line BACKWARD of its RS232C interface, controls the anticlockwise rotation backward of this stepper motor, promptly gets back to the initial position of this measurement; Then, the output control line BACKWARD of said computing machine through its RS232C interface continue output back (=2,3 ...) individual digital pulse signal is to said stepper motor interface circuit, controls the further anticlockwise rotation of this stepper motor; In this process, each one step of anticlockwise rotation all take and analyze respectively take a sample before and after the comparison in the frame view window along all peaks of three kinds of primary colours of X-direction and the number sum N of paddy (i, j=back+1, forw=1, back) and N (i; J=back, forw=1 back=back-1), should have: N (i, j=back+1; Forw=1, back=back)>=N (i, j=back, forw=1; Back=back-1), preserve it, so continue, up to satisfying: N (i; J=back+1, forw=1, back)＜N (i, j=back; Forw=1, back-1), at this moment, record: (back) _MAX=back; Simultaneously; Said computing machine arrives said stepper motor interface circuit through another root output control line FORWARD digital pulse signal of output (forw=2) of its RS232C interface, controls this stepper motor clockwise and rotates a step, at this moment; This measures the preceding initial position of beginning relatively, and the camera of this device promptly is in the best object image-forming focal position in this measurement: FocusP=forw-(back) _MAX=2-(back) _MAX, its result calculated is a negative value, the sense of rotation of representing said stepper motor is anticlockwise, in the corresponding sampling frame view window of this focal position along all peaks of three kinds of primary colours of X-direction and the number sum of paddy is: N (i, j=((back) _MAX-1)+1=(back) _MAX, forw=1, back=(back) _MAXThe tale result of the sampling frame of-1), taking in the measuring process is: j=forw+ (back) _MAX=2+ (back) _MAX

Integrate; This measures the preceding initial position of beginning relatively; The displacement that this optic axis direction of measuring the said camera in object edge that is obtained takes place is: Δ z (i)=forw-back; The value of counter forw and back is count results last in this measuring process in the aforementioned calculation formula, and result of calculation has the symbol of plus or minus, respectively the displacement that taken place of the expression direction of advancing or retreating along optic axis; Corresponding to the sense of rotation of said stepper motor (promptly clockwise or anticlockwise), specifically confirm by the arrangement of the axial displacement device of stepper motor;

Total displacement is: Δ Z ₀(i)=Δ Z ₀(i-1)+Δ z (i)

Wherein, Δ Z ₀(i-1) measure the axial displacement of accumulation before for this;

Step 8, prepare surveying work next time: measure time counter i=i+1, the number sum of getting all peaks of measuring the interior three kinds of primary colours along X-direction of the corresponding object image-forming frame of the best object image-forming focal position view window of confirming for the i time and paddy is as new witness mark value:

N (i, j=0, forw=0, back=0)=N (i, j=(forw) _MAX-1, forw=(forw) _MAX-1, back=0), or N (i, j=0, forw=0, back=0)=N (i, j=((back) _MAX-1)+1=(back) _MAX, forw=1, back=(back) _MAX-1);

Step 9, jump to step 6, continue to measure;

In the actual measurement process,, can obtain direct measurement result through measuring calibration.

Above-mentioned camera is taken and according to the definition of edge direction data described in the step of one dimension three primary colours peak valley DATA REASONING axial displacement program is:

In the pel array, along the X axle or along Y direction, if the light intensity value of a pixel is than the also little error margin value error of second corresponding light intensity value of pixel of its back, if promptly

I (X, Y)＜I (X+2, Y)-error or I (X, Y)＜I (X, Y+2)-error

Then define and have this axial positive limit, an edge between these two pixels; If the light intensity value of a pixel is than the also big error margin value error of second corresponding light intensity value of pixel of its back, if promptly

I (X, Y)＞I (X+2, Y)+error or I (X, Y)＞I (X, Y+2)+error

Then define between these two pixels and to have an edge this is axial marginal; The limit that so obtains is positioned at first locations of pixels after this pixel, also promptly is positioned on that pixel in the centre position of participating in two pixels relatively; If second corresponding light intensity value of pixel of certain light intensity value of a pixel and its back is approaching, its value differs and is no more than an error margin value error, if promptly

I(X+2，Y)-error?≤I(X，Y)≤I(X+2，Y)+error

Or I (X, Y+2)-error≤I (X, Y)≤I (X, Y+2)+error,

Then think not have corresponding " limit " along this direction of principal axis between these two pixels, or be referred to as the 3rd type of limit;

Along some change in coordinate axis direction, all positive limit of corresponding pixel column or pixel column, marginal and the 3rd type of limit form this row maybe should row along the edge direction data of this change in coordinate axis direction; Error margin value in the above-listed formula can be predisposed to a little numerical value, for example: error=10 according to concrete light conditions; There are not the edge direction data in four limits in the pel array and the location of pixels on the angle.

Above-mentioned camera is taken and is comprised according to the method for searching for optimal viewing window pel array described in the step of one dimension three primary colours peak valley DATA REASONING axial displacement program:

For the view window of said pel array and k * k (k ∈ positive integer) associated match operator array (a b), can produce k * k auto correlation matching factor along certain change in coordinate axis direction, by following inequality these auto correlation matching factors relatively:

auto_correlation(a，b)≥auto_correlation(0，0)×similarity

In the formula, similarity has described the similarity degree of the pel array of view window and its contiguous identical scale, for example gets similarity=60%, can be provided with in advance, also can debug and selects according to the quality on light conditions and measured object surface;

If the auto correlation coefficient that satisfies above-mentioned inequality more than k * k * 1/3, need to enlarge each step of scope of view window capable with the step row: make m=m ₀+ step, n=n ₀+ step recomputates the auto correlation coefficient of new view window, and carries out above-mentioned comparison; Up to the no more than k * k of auto correlation matching factor that satisfies above-mentioned inequality * 1/3, at this moment, 2h=M-m; 2v=N-n, wherein, step is a stepped parameter; Initial value is 1, needs the scale of expansion view window just to increase by 1 at every turn; If exceed predetermined scope in the frame, also do not find suitable view window, think that then the quality of this this part reflecting surface of object is inappropriate for the surveying work of this device, and provide the prompting warning;

If satisfy the no more than k * k of auto correlation matching factor of above-mentioned inequality * 1/3; The architectural feature on surface that subject is described is enough meticulous; Value between the neighborhood pixels can be distinguished; Can further attempt dwindling the capable and step row of each step of scope of view window, to reduce amount of calculation: make m=m ₀-step, n=n ₀-step recomputates the auto correlation coefficient of view window, and carries out above-mentioned comparison; The parameter s of going forward one by one tep is each to increase by 1; The number that satisfies the auto correlation coefficient of above-mentioned inequality up to selected view window zone is not less than k * k * 1/3, at this moment, thinks to have searched optimal viewing window pel array.

Above-mentioned camera is taken and according to the definition of edge direction data red, green or blue described in the step of one dimension three primary colours peak valley DATA REASONING axial displacement program is:

Component data according to one of red in the pel array, green or these three kinds of primary colours of blueness; Along the X axle or along Y direction; If certain three primary colours component value of a pixel is than the also little error margin value error of the corresponding three primary colours component value of second pixel of its back, if promptly

I (X, Y) _Red＜I _Red(X+2, Y)-error or I (X, Y) _Red＜I (X, Y+2) _Red-error

I (X, Y) _Green＜I _Green(X+2, Y)-error or I (X, Y) _Green＜I (X, Y+2) _Green-error

I (X, Y) _Blue＜I _Blue(X+2, Y)-error or I (X, Y) _Blue＜I (X, Y+2) _Blue-error

Then define and have a positive limit redness, green or blue between these two pixels; If certain three primary colours component value of a pixel is than the also big error margin value error of the corresponding three primary colours component value of second pixel of its back, if promptly

I (X, Y) _Red＞I _Red(X+2, Y)+error or I (X, Y) _Red＞I (X, Y+2) _Red+ error

I (X, Y) _Green＞I _Green(X+2, Y)+error or I (X, Y) _Green＞I (X, Y+2) _Green+ error

I (X, Y) _Blue＞I _Blue(X+2, Y)+error or I (X, Y) _Blue＞I (X, Y+2) _Blue+ error

Then define and have the marginal of a redness, green or blueness between these two pixels; The limit that so obtains is positioned at first locations of pixels after this pixel, also promptly is positioned on that pixel in the centre position of participating in two pixels relatively; If the corresponding three primary colours component value of second pixel of certain three primary colours component value of a pixel and its back is approaching, its RGB component value differs and is no more than an error margin value error, if promptly

I (X+2, Y) _Red-error≤I (X, Y) _Red≤I (X+2, Y) _Red+ error

Or I (X, Y+2) _Red-error≤I (X, Y) _Red≤I (X, Y+2) _Red+ error;

I (X+2, Y) _Green-error≤I (X, Y) _Green≤I (X+2, Y) _Green+ error

Or I (X, Y+2) _Green-error≤I (X, Y) _Green≤I (X, Y+2) _Green+ error;

I (X+2, Y) _Blue-error≤I (X, Y) _Blue≤I (X+2, Y) _Blue+ error

Or I (X, Y+2) _Blue-error≤I (X, Y) _Blue≤I (X, Y+2) _Blue+ error;

Then think not have this color wavelength corresponding " limit " between these two pixels, or be referred to as the limit of the 3rd type of this color; Along some change in coordinate axis direction; The red edge direction data of this direction are formed on the limit of marginal and the 3rd type of redness of the positive limit of all redness and redness; The green edge direction data of this direction are formed on the limit of marginal and the 3rd type of green of the positive limit of all greens and green, the blue edge direction data of limit this direction of composition of marginal and the 3rd type of blueness of the positive limit of all bluenesss and blueness; Error margin value in the above-mentioned formula can be predisposed to a little numerical value, for example: error=10 according to concrete light conditions; There are not the edge direction data in four limits in the pel array and the location of pixels on the angle.

Above-mentioned camera take and according to described in the step of-Wei three primary colours peak valley DATA REASONING axial displacement program along the limit reflection condition of three kinds of primary colours of X axle and Y direction, it is defined as:

According to redness, green or the blue edge direction data of selected observation row with the pixel of observation row; Along the X axle or along Y direction; If continuous two or more than the positive limit of certain primary colours of two; Or continuous two or more than and then these primary colours marginal after the 3rd type of limit of these primary colours of two, be referred to as the first kind limit reflection condition of these primary colours, promptly think the peak that has these primary colours in this position; If continuous two or marginal more than certain primary colours of two; Or continuous two or more than the and then positive limit of these primary colours after the 3rd type of limit of these primary colours of two; Be referred to as second type of limit reflection condition of these primary colours, promptly think the paddy that has these primary colours in this position; Along the X axle or along Y direction, its all peak of one of three kinds of primary colours and these primary colours of paddy composition diagram picture frame are along the limit reflection condition of this change in coordinate axis direction.

Said camera axial displacement device comprises: said camera is installed on the worktable; This worktable and a long tap turning axle are with the tap socket; This tap turning axle is installed on the big worktable through two bracing frames; And it and these two bracing frames all are the mode sockets with rotating shaft, can rotate at the socket place with bracing frame but displacement does not forward or backward take place; A fixing gear is arranged, the mutual interlock of gear above the rotating shaft of it and stepper motor on the said tap turning axle.Said stepper motor also is installed on the said big worktable, and it is connected to the RS232C interface of computer system through the stepper motor interface circuit.

The optimal viewing zone is analyzed and chosen to the information that the present invention has utilized existing camera to take with the peak and the characteristic of paddy data as the testee picture frame about the pixel three primary colours, through calculating auto correlation coefficient, automatically; Through counting the number of characteristics of image in this viewing area, the degree of judgment object imaging and focusing, and then the micro-displacement that taken place in camera optic axis direction of Measuring Object; " is method and the device of pattern measurement along the displacement of optical axis direction with the three primary colours peak valley " relatively, the advantage of patent of the present invention are that it is half the to analyze the data volume minimizing, has accelerated measuring speed.

Description of drawings

Further specify patent of the present invention below in conjunction with accompanying drawing.

Fig. 1 is computing machine of the present invention and camera measuring system block scheme thereof.

Fig. 2 be of the present invention be the camera axial displacement device block scheme that core is formed by the high-precision micro displacement stepper motor.

Fig. 3 is that optical imagery of the present invention focuses on the process synoptic diagram.

Fig. 4 is that the photoelectric sensor chip carries out the pel array and the view window area schematic thereof that produce after the opto-electronic conversion.

Fig. 5 is the synoptic diagram of a traveling optical signal and digitized signal, edge direction data and limit reflection condition.

Among Fig. 1,1. computing machine camera, 2. optical lens, 3. photoelectric sensor chip; 4.USB interface, 5. computer system, 6.USB interface, 7.CPU; 8.RS232C interface, 9. display card and display, 10. internal memory and hard disk, 11. keyboards and mouse; 12. operating system, 13. webcam driver programs, 14. cameras are taken and according to one dimension three primary colours peak valley DATA REASONING axial displacement program, 15. light fixture.

Among Fig. 2, the worktable of 30. stepper motors and camera, 31. bracing frames; 32. bracing frame, the worktable of 33. cameras (1), 34. tap turning axles; 341. the gear on the tap turning axle (34); 40. stepper motor, the turning axle of 41. stepper motors (40), the gear on the turning axle (41) of 42. stepper motors (40).

Among Fig. 3,90.-96. object (circle hot spot) synoptic diagram that form images in different positions on optical axis, 97. optic axises.

Among Fig. 5,21. 1 traveling optical signals, 22. with the corresponding digitized signal of light signal (21), 23. edge direction data corresponding, the limit reflection condition of 24. corresponding sides directional datas (23) with digitized signal (22).

Embodiment

Patent of the present invention comprises two parts: computing machine shown in Figure 1 and camera measuring system thereof, shown in Figure 2 be the camera axial displacement device that core is formed by the high-precision micro displacement stepper motor.

Go up the webcam driver program (13) of operation the placing in computer system (5), be connected camera (1) with (6) to computing machine (5) through USB interface (4).Then, let camera focal imaging object being measured.

The preferential measurement environment of selecting is indoor.Select the basic demand of measurement environment to be, allow illuminating position that certain variation takes place in measuring process, but the light and shade contrast who does not allow this variation to influence object being measured significantly to be formed images.Select for use light fixture (15) to help enforcement of the present invention.The material of object being measured preferably has more careful surface reflection characteristic, avoids or overcomes smooth reflecting surface material.

As shown in Figure 2, camera (1) is installed on the worktable (33), moves with worktable, and this worktable (33) and a long tap turning axle (34) are with the tap socket.Tap turning axle (34) is installed on the big worktable (30) through bracing frame (31) and (32); And; Tap turning axle (34) all is the mode socket with rotating shaft with bracing frame (31) and (32), and tap turning axle (34) can rotate at the socket place with bracing frame (31) and (32) but displacement does not forward or backward take place.A fixing gear (341) is arranged on the tap turning axle (34); The interlock each other of gear (42) above the rotating shaft (41) of it and stepper motor (40); When the rotating shaft (41) of stepper motor (40) is rotated; Rotation meeting driven gear (341) rotation of gear (42), and then drive tap turning axle (34) rotation, impel camera (1) and worktable (33) thereof to be moved forward or backward together.Stepper motor (40) also is installed on the big worktable (30).

Choose two output signal lines of RS232C interface (8) lining of computer system (5); FORWARD as shown in the figure and BACKWARD; Receive a stepper motor interface circuit (43) with a ground wire GROUND, carry out power amplification at this, then; Be connected to stepper motor (40), control step motor (40) is done clockwise rotation or anticlockwise rotation.

The property relationship of stepper motor (40) is to the measuring accuracy of patent of the present invention, should select that step-wise displacement is meticulous, precision is high, the motor of working stability for use,

The operation camera take and according to-Wei three primary colours peak valley DATA REASONING axial displacement program (14), Displacement Measurement in real time.Concrete steps see that " summary of the invention " describe.

Whether clear the principle of patent measurement optical shaft orientation micrometric displacement of the present invention and method be, as shown in Figure 3 based on optical imagery focusing, and its judgment criterion is: when focusing on clearly, picture frame view window zone has the maximum characteristics of image of number--limit reflection condition.Pel array and view window zone thereof that relevant photoelectric sensor chip carries out producing after the opto-electronic conversion are as shown in Figure 4.The definition of relevant characteristics of image and definite shown in Fig. 5 (edge direction data, edge direction situation).

The described measuring method of patent of the present invention also is applicable to other picture pick-up device.

Claims (6)

1. be the method for pattern measurement axial displacement with one dimension three primary colours peak valley; The displacement that it cooperates a camera, stepper motor and stepper motor interface circuit measurement target thing to take place along the camera optical axis direction through computing machine; It is on the camera axial displacement device formed of core by said stepper motor that this camera is installed in one; This stepper motor is connected to the RS232C interface of said computing machine through said stepper motor interface circuit; It is characterized in that said method comprises the steps: according to the axial displacement of one dimension three primary colours peak valley DATA REASONING

Step 1, the image frame as a reference of taking a frame testee with the form of bitmap M * N, wherein, M, N ∈ positive integer; First locations of pixels with this frame pel array upper left corner is an initial point, is the x direction of principal axis with to the right direction, and vertical downward direction is the y direction of principal axis, and the unit of the coordinate system of getting is the size of a pixel; Choose a zone at the middle section of said pel array, size is m ₀* n ₀, m ₀, n ₀The ∈ positive integer is referred to as view window, and the horizontal direction of the said pel array of its distance and the edge pixel of vertical direction respectively have h and v pixel, promptly have: m ₀+ 2h=M, n ₀+ 2v=N, h, v ∈ positive integer;

Step 2, for the pel array of above-mentioned reference frame; By pixel column, by the edge direction data of pixel column derivation along X-direction and Y direction; And with the binary numeral 001 of 3bit; 010 and 100 wherein positive limit, marginal and the 3rd type of limits of expression respectively, so constituted corresponding said reference frame pel array about X-direction with about two frame edge direction data { reference of Y direction _x(x, y) } and { reference _y(x, y) }, wherein, subscript x or y represent the direction of the coordinate axis on institute edge respectively, all pixels in the change in coordinate axis direction view window that wherein the function subscript is indicated of symbol " { } " expression edge (x, these data are preserved in a set of the edge direction data of y) locating;

Step 3, for above-mentioned two frame edge direction data, calculate the auto correlation matching factor of view window interior pixel array in the said reference frame respectively:

$\mathrm{auto}\_\mathrm{correlati}{\mathrm{on}}_x(a,b)=\underset{y=v+1}{\overset{v+1+n0}{\mathrm{\Σ}}}\underset{x=h+1}{\overset{h+1+m0}{\mathrm{\Σ}}}[\mathrm{referen}{\mathrm{ce}}_x(x,y)\·{\mathrm{reference}}_x(x+a,y+b)]$

$\mathrm{auto}\_\mathrm{correlati}{\mathrm{on}}_y(a,b)=\underset{y=v+1}{\overset{v+1+n0}{\mathrm{\Σ}}}\underset{x=h+1}{\overset{h+1+m0}{\mathrm{\Σ}}}[\mathrm{referen}{\mathrm{ce}}_y(x,y)\·{\mathrm{reference}}_y(x+a,y+b)]$

In the formula, sign of operation is represented binary logic and computing, its operation result or be logical zero or for logical one, the pairing numerical value of value of logical operation function is wherein got in sign of operation " [] " expression; Or be numerical value 0, or be numerical value 1, parametric variable a, the combination of b has determined the scale of associated match operator array; If get 3 * 3 associated match operator arrays: a=-1,0,1, b=-1; 0,1, therefore, each will produce 9 auto correlation coefficient auto_correlation along each change in coordinate axis direction _x(a, b) and auto_correlation _y(a, b);

Step 4, the auto correlation matching factor corresponding according to above-mentioned two frame edge direction data, search for respectively and under present body surface situation and illuminating position, can carry out matching ratio optimal viewing window pel array:

m _x=m ₀± step, n _x=n ₀± step, 2h=M-m _x, 2v=N-n _xAnd m _y=m ₀± step, n _y=n ₀± step, 2h=M-m _y, 2v=N-n _y,

In the formula, subscript x, y represent respectively its value corresponding along X-direction and Y direction, step is the stepped parameter in the search procedure, the unlike signs of its front is determined by the direction of search; Get in this two class value big person and measure the scale of used view window array: m * n for this;

Step 5, for the pel array of above-mentioned reference frame, according to the data of its redness, green and blue component, derive line by line along the redness of X-direction, green and edge direction data blueness, one has 3 * 1=3 frame edge direction data;

According to the edge direction data of above-mentioned three kinds of primary colours, derive along the limit reflection condition of three kinds of primary colours of X-direction, have 3 * 1=3 frame limit reflection condition; For view window zone wherein, use the number of their pairing peaks of accumulator count, paddy: N respectively _{RX axle peak}And N _{RX axle paddy}, N _{GX axle peak}And N _{GX axle paddy}, N _{BX axle peak}And N _{BX axle paddy}, wherein, N representes number, R, G, B represent red, green and blue respectively; Add up above-mentioned totalizer count results and preserve it, be expressed as: N (i, j=0, forw=0, back=0), wherein; I=1,2,3...... representes the sequential counting of captured reference frame, also is the counting of measuring, j=0; 1,2,3 ..., the rotation of stepper motor generation clockwise was counted with the pairing step-by-step impulse of anticlockwise rotation described in the counting of the sampling frame of representing to take in the i time measuring process, variable forw and back were represented respectively to measure for the i time: forw=0; 1,2 ..., back=0,1,2 ...; Before this measures beginning, have: i=1, j=0, forw=0, back=0;

Step 6, measurement beginning: said computing machine is exported forw=1 digital pulse signal to said stepper motor interface circuit through an output control line FORWARD of its RS232C interface; Control this stepper motor clockwise and rotate a step; Then, take j=1 frame sample framing bit figure;

For the pel array of above-mentioned sampling frame, according to the data of its redness, green and blue component, derive line by line along the redness of X-direction, green and edge direction data blueness, have 3 * 1=3 frame edge direction data;

According to the edge direction data of above-mentioned three kinds of primary colours, derive along the limit reflection condition of three kinds of primary colours of X-direction, have 3 * 1=3 frame limit reflection condition; For view window zone wherein, use the number of their pairing peaks of accumulator count, paddy: N respectively _{RX axle peak}And N _{RX axle paddy}, N _{GX axle peak}And N _{GX axle paddy}, N _{BX axle peak}And N _{BX axle paddy}Add up above-mentioned totalizer count results and preserve it, be expressed as: N (i, j=1, forw=1, back=0);

If step 7: N (i, j=1, forw=1, back=0)>=N (i, j=0, forw=0; Back=0), said computing machine is exported forw digital pulse signal to said stepper motor interface circuit through an output control line FORWARD of its RS232C interface, and it is progressive to control this stepper motor clockwise rotation, and forw=2,3 are promptly arranged successively; ..., each one step of clockwise rotation all take and analyze respectively take a sample before and after the comparison in the frame in the view window along all peaks of three kinds of primary colours of X-direction and the number sum N of paddy (i, j=forw-1, forw-1, back=0) and N (i; J=forw, forw back=0), preserves it, should have in this process: N (i; J=forw, forw, back=0)>=N (i, j=forw-1, forw-1; Back=0), up to satisfying: N (i, j=forw, forw, back=0)＜N (i; J=forw-1, back-1, back=0), and at this moment, record (forw) _MAX=forw; Simultaneously, said computing machine arrives said stepper motor interface circuit through digital pulse signal of another root output control line BACKWARD output of its RS232C interface, controls anticlockwise one step of rotation of this stepper motor; Back=1 is promptly arranged; At this moment, this measures the preceding initial position of beginning relatively, and the camera of this device promptly is in the best object image-forming focal position in this measurement: FocusP=(forw) _MAX-back=(forw) _MAX-1; Its result calculated is more than or equal to 0; The sense of rotation of representing said stepper motor in general is clockwise, in the corresponding sampling frame view window of this focal position along all peaks of three kinds of primary colours of X-direction and the number sum of paddy is: N (i, j=(forw) _MAX-1, forw=(forw) _MAX-1, back=0), the tale result of the sampling frame of taking in the measuring process is: j=(forw) _MAX+ back=(forw) _MAX+ 1;

If: N (i, j=1, forw=1, back=0)＜N (i, j=0; Forw=0, back=0), said computing machine is exported back=1 digital pulse signal to said stepper motor interface circuit through an output control line BACKWARD of its RS232C interface, controls the anticlockwise rotation backward of this stepper motor, promptly gets back to the initial position of this measurement; Then, said computing machine continues back digital pulse signal of output to said stepper motor interface circuit through the output control line BACKWARD of its RS232C interface, controls the further anticlockwise rotation of this stepper motor, and back=2,3 are promptly arranged successively; ..., in this process, each one step of anticlockwise rotation all takes and analyzes and respectively takes a sample before and after the comparison in the frame view window along all peaks of three kinds of primary colours of X-direction and number sum N (i, j=back+1, the forw=1 of paddy; Back) and N (forw=1 back=back-1), should have: N (i for i, j=back; J=back+1, forw=1, back=back)>=N (i, j=back, forw=1; Back=back-1), preserve it, so continue, up to satisfying: N (i; J=back+1, forw=1, back)＜N (i, j=back; Forw=1, back-1), at this moment, record: (back) _MAX=back; Simultaneously, said computing machine arrives said stepper motor interface circuit through digital pulse signal of another root output control line FORWARD output of its RS232C interface, controls this stepper motor clockwise and rotates a step; At this moment; Forw=2, this measures the preceding initial position of beginning relatively, and the camera of this device promptly is in the best object image-forming focal position in this measurement: FocusP=forw-(back) _MAX=2-(back) _MAX, its result calculated is a negative value, the sense of rotation of representing said stepper motor is anticlockwise, in the corresponding sampling frame view window of this focal position along all peaks of three kinds of primary colours of X-direction and the number sum of paddy is: N (i, j=((back) _MAX-1)+1=(back) _MAX, forw=1, back=(back) _MAXThe tale result of the sampling frame of-1), taking in the measuring process is: j=forw+ (back) _MAX=2+ (back) _MAX

Integrate, this measures the preceding initial position of beginning relatively, and the displacement that this optic axis direction of measuring the said camera in object edge that is obtained takes place is: Δ z (i)=forw-back,

The value of counter forw and back is count results last in this measuring process in the aforementioned calculation formula; This result has the symbol of plus or minus; The displacement that taken place of the expression direction of advancing or retreating respectively along optic axis; Corresponding to the sense of rotation of said stepper motor clockwise or anticlockwise promptly, specifically confirm by the arrangement of the axial displacement device of stepper motor;

Total displacement is: Δ Z ₀(i)=Δ Z ₀(i-1)+Δ z (i)

Wherein, Δ Z ₀(i-1) measure the axial displacement of accumulation before for this;

Step 8, prepare surveying work next time: measure time counter i=i+1, the number sum of getting all peaks of measuring the interior three kinds of primary colours along X-direction of the corresponding object image-forming frame of the best object image-forming focal position view window of confirming for the i time and paddy is as new witness mark value:

N (i, j=0, forw=0, back=0)=N (i, j=(forw) _MAX-1, forw=(forw) _MAX-1, back=0), or N (i, j=0, forw=0, back=0)=

N(i，j＝((back) _MAX-1)+1＝(back) _MAX，forw＝1，back＝(back) _MAX-1)；

Step 9, jump to step 6, continue to measure.

2. according to claim 1 is the method for pattern measurement axial displacement with one dimension three primary colours peak valley, it is characterized in that the definition of edge direction data described in the said step is:

In the pel array, along the X axle or along Y direction, if the light intensity value of a pixel is than the also little error margin value error of second corresponding light intensity value of pixel of its back, if promptly

I (X, Y)＜I (X+2, Y)-error or I (X, Y)＜I (X, Y+2)-error

Then define and have this axial positive limit, an edge between these two pixels; If the light intensity value of a pixel is than the also big error margin value error of second corresponding light intensity value of pixel of its back, if promptly

I (X, Y)＞I (X+2, Y)+error or I (X, Y)＞I (X, Y+2)+error

Then define between these two pixels and to have an edge this is axial marginal; The limit that so obtains is positioned at first locations of pixels after this pixel, also promptly is positioned on that pixel in the centre position of participating in two pixels relatively; If second corresponding light intensity value of pixel of certain light intensity value of a pixel and its back is approaching, its value differs and is no more than an error margin value error, if promptly

I(X+2，Y)-error≤I(X，Y)≤I(X+2，Y)+error

Or I (X, Y+2)-error≤I (X, Y)≤I (X, Y+2)+error,

Then think not have corresponding " limit " along this direction of principal axis between these two pixels, or be referred to as the 3rd type of limit;

Along some change in coordinate axis direction, all positive limit of corresponding pixel column or pixel column, marginal and the 3rd type of limit form this row maybe should row along the edge direction data of this change in coordinate axis direction; Error margin value in the above-listed formula can be predisposed to a little numerical value according to concrete light conditions; There are not the edge direction data in four limits in the pel array and the location of pixels on the angle.

3. according to claim 1 is the method for pattern measurement axial displacement with one dimension three primary colours peak valley, it is characterized in that, the method for the optimal viewing of search described in said step window pel array comprises:

For the view window of said pel array and k * k associated match operator array (a, b), k ∈ positive integer can produce k * k auto correlation matching factor along certain change in coordinate axis direction, by following inequality these auto correlation matching factors relatively:

auto_correlation(a，b)≥auto_correlation(0，0)×similarity

In the formula, similarity has described the similarity degree of the pel array of view window and its contiguous identical scale, can be provided with in advance, also can debug and selects according to the quality on light conditions and measured object surface;

If the auto correlation coefficient that satisfies above-mentioned inequality more than k * k * 1/3, need to enlarge each step of scope of view window capable with the step row: make m=m ₀+ step, n=n ₀+ step recomputates the auto correlation coefficient of new view window, and carries out above-mentioned comparison; Up to the no more than k * k of auto correlation matching factor that satisfies above-mentioned inequality * 1/3, at this moment, 2h=M-m; 2v=N-n, wherein, step is a stepped parameter; Initial value is 1, needs the scale of expansion view window just to increase by 1 at every turn; If exceed predetermined scope in the frame, also do not find suitable view window, think that then the quality of this this part reflecting surface of object is inappropriate for the surveying work of this device, and provide the prompting warning;

If satisfy the no more than k * k of auto correlation matching factor of above-mentioned inequality * 1/3; The architectural feature on surface that subject is described is enough meticulous; Value between the neighborhood pixels can be distinguished; Further attempt dwindling the capable and step row of each step of scope of view window, to reduce amount of calculation: make m=m ₀-step, n=n ₀-step recomputates the auto correlation coefficient of view window, and carries out above-mentioned comparison; Stepped parameter step is each to increase by 1; The number that satisfies the auto correlation coefficient of above-mentioned inequality up to selected view window zone is not less than k * k * 1/3, at this moment, thinks to have searched optimal viewing window pel array.

4. according to claim 1 is the method for pattern measurement axial displacement with one dimension three primary colours peak valley, it is characterized in that, the definition of red, green or blue edge direction data described in the said measuring process is:

Component data according to one of red in the pel array, green or these three kinds of primary colours of blueness; Along the X axle or along Y direction; If certain three primary colours component value of a pixel is than the also little error margin value error of the corresponding three primary colours component value of second pixel of its back, if promptly:

I (X, Y) _Red＜I _Red(X+2, Y)-error or I (X, Y) _Red＜I (X, Y+2) _Red-error

I (X, Y) _Green＜I _Green(X+2, Y)-error or I (X, Y) _Green＜I (X, Y+2) _Green-error

I (X, Y) _Blue＜I _Blue(X+2, Y)-error or I (X, Y) _Blue＜I (X, Y+2) _Blue-error

Then define and have a positive limit redness, green or blue between these two pixels; If certain three primary colours component value of a pixel is than the also big error margin value error of the corresponding three primary colours component value of second pixel of its back, if promptly: I (X, Y) _Red＞I _Red(X+2, Y)+error or I (X, Y) _Red＞I (X, Y+2) _Red+ error

I (X, Y) _Green＞I _Green(X+2, Y)+error or I (X, Y) _Green＞I (X, Y+2) _Green+ error

I (X, Y) _Blue＞I _Blue(X+2, Y)+error or I (X, Y) _Blue＞I (X, Y+2) _Blue+ error

Then define and have the marginal of a redness, green or blueness between these two pixels; The limit that so obtains is positioned at first locations of pixels after this pixel, also promptly is positioned on that pixel in the centre position of participating in two pixels relatively; If the corresponding three primary colours component value of second pixel of certain three primary colours component value of a pixel and its back is approaching, its RGB component value differs and is no more than an error margin value error, if promptly:

I (X+2, Y) _Red-error≤I (X, Y) _Red≤I (X+2, Y) _Red+ error

Or I (X, Y+2) _Red-error≤I (X, Y) _Red≤I (X, Y+2) _Red+ error;

I (X+2, Y) _Green-error≤I (X, Y) _Green≤I (X+2, Y) _Green+ error

Or I (X, Y+2) _Green-error≤I (X, Y) _Green≤I (X, Y+2) _Green+ error;

I (X+2, Y) _Blue-error≤I (X, Y) _Blue≤I (X+2, Y) _Blue+ error

Or I (X, Y+2) _Blue-error≤I (X, Y) _Blue≤I (X, Y+2) _Blue+ error;

Then think not have this color wavelength corresponding " limit " between these two pixels, or be referred to as the limit of the 3rd type of this color; Along some change in coordinate axis direction; The red edge direction data of this direction are formed on the limit of marginal and the 3rd type of redness of the positive limit of all redness and redness; The green edge direction data of this direction are formed on the limit of marginal and the 3rd type of green of the positive limit of all greens and green, the blue edge direction data of limit this direction of composition of marginal and the 3rd type of blueness of the positive limit of all bluenesss and blueness; Error margin value in the above-mentioned formula can be predisposed to a little numerical value according to concrete light conditions; There are not the edge direction data in four limits in the pel array and the location of pixels on the angle.

5. according to claim 1 is the method for pattern measurement axial displacement with one dimension three primary colours peak valley, it is characterized in that, along the limit reflection condition of three kinds of primary colours of X-direction, it is defined as described in the said measuring process:

Redness, green or blue edge direction data according to the pixel of selected observation row; Along X-direction; If continuous two or more than the positive limit of certain primary colours of two; Or continuous two or more than and then these primary colours marginal after the 3rd type of limit of these primary colours of two, be referred to as the first kind limit reflection condition of these primary colours, promptly think the peak that has these primary colours in this position; If continuous two or marginal more than certain primary colours of two; Or continuous two or more than the and then positive limit of these primary colours after the 3rd type of limit of these primary colours of two; Be referred to as second type of limit reflection condition of these primary colours, promptly think the paddy that has these primary colours in this position; Along X-direction, its all peak of one of three kinds of primary colours and these primary colours of paddy composition diagram picture frame are along the limit reflection condition of this change in coordinate axis direction.

6. according to claim 1 is the method for pattern measurement axial displacement with one dimension three primary colours peak valley, it is characterized in that said camera axial displacement device comprises:

Camera (1) is installed on first worktable (33); First worktable (33) and a long tap turning axle (34) are with the tap socket; Tap turning axle (34) is installed on second worktable (30) through first bracing frame (31) and second bracing frame (32); And; Tap turning axle (34) all is the mode socket with rotating shaft with first bracing frame (31) and second bracing frame (32), and tap turning axle (34) can rotate at the socket place with first bracing frame (31) and second bracing frame (32) but displacement does not forward or backward take place; A fixing gear (341) is arranged, the interlock each other of the gear (42) above the rotating shaft (41) of it and stepper motor (40) on the tap turning axle (34); Stepper motor (40) also is installed on second worktable (30), and it is connected to the RS232C interface of said computing machine through stepper motor interface circuit (43).

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