CN102519965A - Online roadbed compactness detection method based on machine vision - Google Patents

Abstract

The invention discloses an online roadbed compactness detection method based on machine vision and belongs to the field of roadbed compactness detection method. The online roadbed compactness detection method comprises the following steps of: (1) establishing a vision measurement system: a measurement system for one compactness sampling point consists of a CCD ( Charge Coupled Device ) camera, a sampling mark feature point and a mark pile; (2) image processing: the CCD camera collects the image of a compaction site and obtains three crossed shapes of the mark pile through fitting, and the image coordinate of the center of sampling mark feature point and the long axis and short axis parameters of an ellipse are extracted; (3) settlement calculation: the vertical distance between the center of the sampling mark feature point and a selected reference point of the mark pile is obtained through calculation, and the settlement of the compaction operation is obtained; and (4) roadbed compactness calculation: the settlement is substituted into the settlement-compactness mathematical model. The online roadbed compactness detection method takes images as the carrier for detection and information transfer; and as image data is stored in a computer, construction documents can be well saved, and the quality and efficiency of compaction operation are improved.

Description

A kind of Subgrade Compaction online test method based on machine vision

Technical field

The present invention relates to a kind of Subgrade Compaction detection method, more particularly, relate to a kind of Subgrade Compaction online test method based on machine vision.

Background technology

Compactness is meant the ratio of dry density and standard maximum dry density after soil or other road-making material compactings, representes with percent.Compactness is one of key index of detecting of subgrade and pavement construction quality, characterizes the density situation after the on-the-spot compacting, and compactness is high more, and density is big more, and the material monolithic performance is good more.Compactness detects the method that adopts random sampling usually, promptly on the material that rolled, takes a sample, and survey density, static modulus of elasticity reflect compaction quality.The method of normally used random sampling detection compactness has core cutter method, sand replacement method, nucleon compactness appearance method, irritates oil process, water bag method etc. on the engineering.Except that nucleon compactness appearance method, be the destructive test assessment method, and order of accuarcy depends on manual skill level as a result in the said method, be can not continuous sampling assessment method.It is fast that nucleon compactness appearance method has measuring speed, do not destroy advantages such as soil layer construction, can be used for continuous sampling.But this method price is high, and the environment for use condition is harsh, and radiomaterial is harmful in addition, in case the generation problem also can cause environmental pollution.

Begin the beginning of the seventies in last century; The earthwork construction amount is increasing; Adopt traditional compactness detection method to be difficult to satisfy construction demand and guiding construction operation in time; The begin one's study online measuring technique of compactness of more external experts, compactness online detection and control technology is the new direction of modern compaction technology, it is along with the development of hydraulic technique, electron controls technology occurs.Configuration compactness on-line detecting system detects the compaction of compacting material immediately, thereby has improved compacting operation quality and operating efficiency on street roller.The compactness on-line detecting system is undoubtedly the indispensable parts of following intelligent vibroll.

The seventies in 20th century; The begin one's study online detection of compactness of the compacting expert of Sweden; They install a three axis accelerometer on the vibroll vibrating wheels; Hang a micro-wheels after the vibrating wheels and be used for detecting vibration, get off a seismoreceiver to test the vibration of ground again with being embedded in from the transmission of vibrating wheels to micro-wheels.The signal of receiving through each sensor draws, and along with the increase of soil compaction, the signal that the accelerometer on the vibrating wheels collects changes the most obvious.And carry out experimental study, through every all over the in-site measurement digital proof after the compacting be feasible with the vibrating wheels acceleration signal as measuring object.Under the enlightenment of this test, the Geodynamics company of Sweden has developed first compactness meter in the world in 1975-1977, and the compacting meeting that early 1980s holds in Paris enters on the compactness meter first as international subject under discussion.After this, domestic and international many scientific research institutions and famous compacting machinary manufacturer participate in this research work in succession, have obtained certain achievement, have developed some products.Yet domestic and international existing compactness online measuring technique has a common ground, all is that applying vibration wheel acceleration signal carries out mathematical modeling, realizes that compactness is online to obtain.

Machine vision is meant and utilizes computing machine and some utility appliance to realize people's visual performance, thereby realizes being an emerging subject through extraneous things of two dimensional image perception and objective three-dimensional world, is one of interesting forward position research field.Along with the development of machine vision technique, a kind of be used as image occurred to detect and the means of the information of transmission or the new detection method that carrier is used, promptly based on the image detecting technique of machine vision.It is to be the basis with the contemporary optics, melts science and technology such as optoelectronics, computer graphics, information processing, machine vision and is the modern detecting of one.Instrument and equipment based on the image detecting technique of machine vision can be realized intellectuality, digitizing, miniaturization, networking and multifunction; Possess the ability of online detection, real-time analysis, real-time control, obtain extensive concern and application in fields such as military affairs, industry, medical science.

On compacting equipment, adopt the online detection Subgrade Compaction of vision measurement technology; It is a kind of road quality Non-Destructive Testing new technology; Can make the staff in compacting process, detect the compacting situation in real time, the control compaction quality, thus guarantee that subgrade and pavement obtains abundant compacting under minimum number of rolling; Avoid phenomenons such as the not enough or undue compacting of compacting, have obvious social and economic benefit.Increasing measuring point, can also record two operation quality parameters of irregularity degree and overlapping width, is that other are incomparable at the compactness line detecting method.In addition, can also use the image information of acquisition, instruct safe construction.Therefore, utilization combines multi-disciplinary visible sensation method such as mechanics, mechanics, electronics and digital signal processing and obtains the compacting operation mass parameter, has suitable theoretical research and is worth and wide application prospect.

1. the prior art one relevant with the present invention

The technical scheme of prior art one: People's Republic of China's industry standard " highway subgrade road surface on-the-spot test rules " stipulates that (JTJ059-95) Subgrade Compaction can adopt the sand replacement method of digging pit (T0921-95), nucleon appearance method (T0922-95) and core cutter method (T0923-95) to measure.People's Republic of China's standard " vibroll method for testing performance " (GB/T 4478-1995) regulation selects for use core cutter method to measure compactness, the consolidation effect of checking street roller.Following mask body narration core cutter method is measured the compactness step:

(1) compaction test.According to relevant test methods test samples is carried out compaction test with same material, obtain maximum dry density ρ _cAnd optimum moisture content;

(2) clean and change to, take by weighing the cutting ring mass M ₂, be accurate to 0.1g;

(3) sampling spot cleaning is clean, and compacted lift is scalped the surface float and irregular part, reach certain depth, cutting ring is laid after, can meet the requirements of the degree of depth that fetches earth, but must not be with lower floor's disturbance;

(4) the cutting ring mouth down places sampling spot, covers the cutting ring lid, and hammering cutting ring lid makes cutting ring reach sampling depth, notes in the process keeping cutting ring vertically downward;

(5) remove the cutting ring lid, cutting ring and sample are dug out with pick;

(6) with repair native cutter from the limit to the surplus soil in middle cancellation cutting ring two ends, detect till equating with ruler;

(7) clean the cutting ring outer wall, weigh in the balance and take out cutting ring and sample total mass M ₁, be accurate to 0.1g;

(8) in cutting ring, take out sample, get representative sample, measure its water cut w.

(9) the measuring point compactness is calculated:

$\mathrm{\&rho;}=\frac{4\&times;(M_1-M_2)}{\mathrm{\&pi;}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="111215073027.png,111215073031.png"\; state="\{\{state\}\}">d</figure-callout>}}^2\&CenterDot;h}$

${\mathrm{\&rho;}}_d=\frac{\mathrm{\&rho;}}{1+0.01w}$

$K=\frac{{\mathrm{\&rho;}}_d}{{\mathrm{\&rho;}}_c}\&times;100$

In the formula: ρ---sample wet density, g/cm ³

ρ _d---sample dry density, g/cm ³

M ₁---cutting ring and sample add up to weight, g;

M ₂---cutting ring weight, g;

D---cutting ring diameter, cm;

H---cutting ring height, cm;

W---water cut, %;

ρ _c---maximum dry density, g/cm ³

K---measuring point compactness, %.

The shortcoming of prior art one: there is following shortcoming in above-mentioned detection method,

(1) this assay method need destroy soil layer construction, and too much sampling influences the roadbed performance, and the fewer data confidence level of sampled point is lower;

(2) not energy measurement and assessment compaction state in the compacting process can only detect after compacting finishes;

(3) the test findings accuracy depends on operating personnel's skills involved in the labour;

(4) working strength of workers is bigger;

(5) detection speed is slow, can't realize online detection.

The sand replacement method method step of digging pit that " highway subgrade road surface on-the-spot test rules " are mentioned in (JTJ059-95) is similar with above-mentioned core cutter method, also has above-mentioned weak point.Nucleon appearance method can be implemented in line and detects, but this method possibly cause nuclear leakage, and the threat personnel are healthy, can cause environmental pollution.

2. the prior art two relevant with the present invention

Vibroll-soil the mathematical model of the technical scheme of prior art two: Fig. 1 for obtaining based on a series of hypothesis, the paper of writing from Li Xishan etc. " research of vibroll compactness appearance ".Reach a conclusion through Numerical Simulation Analysis, the vibrating wheels acceleration amplitude is with soil stiffness K ₂Increase and become big; On the contrary, the vibrating wheels acceleration amplitude is with soil damping C ₂Increase and diminish.Be fruitful and point out, in actual compacting process, along with the carrying out of compacting, compactness increases gradually, and it is big that the rigidity of soil also becomes gradually, and damping diminishes gradually.In view of the above, be not difficult to draw acceleration amplitude and become big conclusion with the compactness increase, promptly the two has positive correlation.The method that adopts this principle to detect compactness is called the amplitude ratioing technigue.Concrete steps:

(1) arranges acceleration transducer in the vibrating wheels appropriate position, and configure signal acquiring system;

(2) in selected certain bid section of engineering certain limit as test section; Carry out 8-12 time subgrade compaction operation according to relevant rules, and when the 2nd, 6,8 time (carrying out 12 times compactings also should comprise the 10th, 12 time) compacting finishes, adopt the compactness of core cutter method determination test section;

(3) acceleration signal of compacting operation process is analyzed, obtained (carrying out 12 times compactings also should comprise the 10th, 12 time) acceleration signal amplitude the 2nd, 6,8 time;

(4) the compactness data and the acceleration amplitude data that obtain with core cutter method are carried out data fitting, set up the mathematical model that characterizes compactness with acceleration amplitude;

(5) this project subgrade engineering promptly forecasts construction quality with this mathematical model.

The shortcoming of prior art two: at present; The positive correlation of acceleration amplitude and compactness is too controversial; And the applicant organized and implemented repeatedly vibrating compacting test during majoring in the master, finds the carrying out along with compacting, and compactness is increasing gradually; But unusual performance has but appearred in acceleration signal, and parameter differences such as grating that maybe be native, water cut cause.That is to say, along with the difference of laminated material character, such as the sandy soil of northern Shensi, the amplitude of acceleration is not necessarily to increase with compactness to become big, thereby has influenced the compactness meter of developing according to this principle.In addition, this compactness meter in use must be before each project begins the chosen in advance test section, carry out mathematical modeling (some achievement is called demarcation), this has just influenced its broad applicability.

3. the prior art three relevant with the present invention

The technical scheme of prior art three: in compacting operation, the compacting initial stage, vibration frequency was mainly fundamental frequency, can not produce higher hamonic wave because soil is softer; But along with the carrying out of compacting, the soil compaction rate increases, and then can produce higher hamonic wave.Be that higher hamonic wave generation and signal distortion degree and compactness have close getting in touch, in order to disclose the objective law of the two, domestic and international many scholars have gathered sight on the harmonic ratio HVR, i.e. fundamental frequency amplitude and this parameter of secondary harmonic amplitude ratio.Fig. 2 quotes from Deutsche Bundespatent (DE 3308476/AI).Can be reached a conclusion by Fig. 2, harmonic ratio HVR changes along with compacting counting is increased in according to certain rules.The method of carrying out the compactness detection according to this principle is called the harmonic ratio method.Concrete steps are following:

(1) arranges acceleration transducer in the vibrating wheels appropriate position, and configure signal acquiring system;

(2) in selected certain bid section of engineering certain limit as test section; Carry out 8-12 time subgrade compaction operation according to relevant rules, and when the 2nd, 6,8 time (carrying out 12 times compactings also should comprise the 10th, 12 time) compacting finishes, adopt the compactness of core cutter method determination test section;

(3) acceleration signal of compacting operation process is analyzed, obtained (carrying out 12 times compactings also should comprise the 10th, 12 time) acceleration signal harmonic ratio HVR the 2nd, 6,8 time;

(4) the compactness data and the acceleration amplitude data that obtain with core cutter method are carried out data fitting, set up the mathematical model that characterizes compactness with acceleration amplitude;

(5) this project subgrade engineering promptly forecasts construction quality with this mathematical model.

The shortcoming of prior art three: at first; The applicability of this compactness meter in some new debulking methods is still waiting checking; Like the good proposition chaos of China Agricultural University's dragon cloud compact technique, the vibrating wheels acceleration signal all has distribution in wide range, and harmonic components is not fairly obvious.The graceful protecting against shock vibrating compaction method of proposition and the compound debulking methods of impact shock that the poplar people of Chang An University phoenix proposes of waiting of the Liu Xiao of Chang An University, acceleration signal also is to be distributed in the very wide frequency range.

Summary of the invention

1. invent the technical matters that will solve

The invention reside in and overcome deficiency of the prior art; A kind of Subgrade Compaction detection method based on machine vision is proposed; Settle the marker peg of some along the line at construction section; The sign of arranging regular geometry at the road surfaces tested point obtains the highway section high precision image fast as unique point, adopts simple image processing algorithm to obtain the positional information of unique point in the vertical direction; Relatively obtain this compacting settling amount with the position data of measuring gained last time again, bring calculated with mathematical model into and obtain compactness.

2. technical scheme

For achieving the above object, technical scheme provided by the invention is:

A kind of Subgrade Compaction online test method based on machine vision of the present invention the steps include:

(1) set up vision measurement system:

The compactness of a compactness sampled point is measured; Its measuring system is made up of 1 CCD camera, 1 sampling flag sign point and 1 marker peg, when a plurality of compactness sampled points are sampled, and then corresponding increase sampling flag sign point and marker peg quantity; Wherein, Marker peg amounts to and divides three layers, and every layer is " ten " font, is designated as face from left to right respectively ₁, face ₂With face ₃, the angle point of these three faces is labeled as 1,2 successively, 3..., 12;

(2) Flame Image Process:

The CCD camera is gathered the compacting image scene, extracts three layers of image coordinate that amounts to 36 points of marker peg then, and match obtains three " ten " fonts of marker peg; Extract the image coordinate of sampling flag sign dot center and oval major semi-axis and the oval minor semi-axis Pixel Dimensions size parameter after the imaging of circular sampling flag sign point;

(3) settling amount calculates:

Full-size(d) and picture size according to " ten " font full-size(d) and picture size and sampling flag sign point; Calculate sampling flag sign dot center to the vertical range between the selected RP of marker peg; Previous with it vertical range is compared, and obtains the settling amount of this compacting operation;

(4) Subgrade Compaction is calculated:

Settling amount substitution settling amount-compactness mathematical model with step (3) obtains can calculate the new compactness of roadbed.

Further, the marker peg in the step (1) is arranged near the compactness sampled point, this compactness sampled point and marker peg within the visual field of CCD camera, wherein, marker peg be arranged in construction section along the line on, face ₁, face ₂With face ₃Be parallel to each other face ₁Perpendicular with the construction road surface; Compactness sampling flag sign point is the mode through spray paint, at road surfaces compactness sample point spraying circle marker as unique point.

Further, in the imaging model of step (2) Flame Image Process, establish O _c-X _cY _cZ _cBe CCD camera coordinates system, O _cBe CCD camera photocentre, Z _cAxle and CCD camera optical axis coincidence are with world coordinate system (O _w-X _wY _wZ _w) overlap with CCD camera coordinates system, I is the picture plane, and O-XY is image physical coordinates system, and o-uv is the image pixel coordinate system, P _IjBe face _i(i=1,2,3) last j angle point (j=1,2 ..., 12), corresponding picture point is used P _Ij' expression, P ₀Be artificial target's compactness sampling flag sign point, be the measuring point of settling amount, picture point is designated as P ₀'; Set following parameter or geometric condition:

A) P _IjAt O _c-X _cY _cZ _cOn coordinate use

Expression;

B) P _Ij' coordinate on image coordinate system O-XY is with (X ^Ij, Y ^Ij) expression;

C) P _Ij' be that coordinate on the o-uv is with (u at pixel coordinate ^Ij, v ^Ij) expression;

D) focal length of camera is represented with f;

E) pixel is respectively dx and dy at imaging plane X and Y direction size;

F) coordinate of the initial point of coordinate system O-XY on image pixel coordinate system o-uv is (u ₀, v ₀);

G) if line segment p _Ijp _Ij+1In camera coordinates system is vertical direction, so p _Ij+1p _Ij+2Horizontal direction must be in, p might as well be supposed _Ijp _Ij+1Line segment for vertical direction in the camera coordinates system;

Get P _Ij, P _Ij+1And P _Ij+2Three points, in conjunction with imaging model, its imaging process is following:

According to the pinhole imaging system principle, obtain following equality and set up:

$\left\{\begin{array}{c}{X}^{\mathrm{ij}}=f\&CenterDot;({X_c}^{\mathrm{ij}}/{Z_c}^i)\\ Y^{\mathrm{ij}}=f\&CenterDot;({Y_c}^{\mathrm{ij}}/{Z_c}^i)\end{array}\right.---\left(0.1\right)$

$\left\{\begin{array}{c}{u}^{\mathrm{ij}}=X^{\mathrm{ij}}/\mathrm{dx}+u_0\\ v^{\mathrm{ij}}=Y^{\mathrm{ij}}/\mathrm{dy}+v_0\end{array}\right.---\left(0.2\right)$

Note point P _IjWith a P _Ij+1Distance between two points is l ₁, some P _Ij' and some P _Ij+12 pel spacings are from being l ₁', then have:

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="111215073031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1={Y_c}^{\mathrm{ij}}-{Y_c}^{\mathrm{ij}+1}\\ {\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="111215073031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1^{\&prime;}=v^{\mathrm{ij}}-v^{\mathrm{ij}+1}=\frac{f}{\mathrm{dy}}\&CenterDot;\frac{{Y_c}^{\mathrm{ij}}-{Y_c}^{\mathrm{ij}+1}}{{Z_c}^i}\end{array}\right.---\left(0.3\right)$

β is compared in the measurement of definition vertical direction _⊥:

${\mathrm{\&beta;}}_{\&perp;}=\frac{l_1}{{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="111215073031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1^{\&prime;}}=\frac{{Z_c}^i}{f/\mathrm{dy}}---\left(0.4\right)$

β is compared in the measurement that can define horizontal direction equally _-:

${\mathrm{\&beta;}}_{-}=\frac{{Z_c}^i}{f/\mathrm{dx}}---\left(0.5\right)$

Above-mentioned measurement is than being to be used for the physical quantity that the characterization of visual measuring system concerns between given distance testee physical dimension and Pixel Dimensions;

Face ₁There are six to be parallel to X _cThe limit of axle; Be horizontal sides, can obtain the measurement ratio of six horizontal directions after the imaging, Chen Xiangwei points out in its doctorate paper " research of Computer Vision Inspection of Mechanical Part gordian technique "; The imaging of diverse location place obtains to measure ratio in the visual field; Can eliminate the distortion of vision system, therefore, with the mean value of the measurement ratio of six horizontal directions as face ₁The measurement ratio of position horizontal direction is used symbol

Expression, same, can obtain face ₂The measurement ratio of position horizontal direction

Face ₃The measurement ratio of position horizontal direction

Face ₁There are six to be parallel to Y _cThe limit of axle is vertical edge, can obtain the measurement ratio of six vertical directions after the imaging, too with the method for averaging, calculates the that appears ₁The measurement ratio of position vertical direction

In like manner, get face ₂The measurement ratio of position vertical direction

Face ₃Vertical square of position to the measurement ratio

Δ ₁₂And Δ ₁₃Be two process variable, represent the distance between first cross and second cross respectively, and the distance between first cross and the thirty word; C1 representes the variable Δ ₁₂Value; C2 representes the variable Δ ₁₃Value, then have:

$\left\{\begin{array}{c}{{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{-}}^1=\frac{{Z_c}^1}{f/\mathrm{dx}}\\ {{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{-}}^2=\frac{{Z_c}^2}{f/\mathrm{dx}}\\ {{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{-}}^3=\frac{{Z_c}^3}{f/\mathrm{<figure-callout\; id="1"\; label="dx\; Z\; c"\; filenames="111215073031.png"\; state="\{\{state\}\}">dx</figure-callout>}}& \\ {Z_c}^{}{{}_{}}^1={{\mathrm{<figure-callout\; id="2"\; label="Z\; c"\; filenames="111215073027.png,111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^2+{\mathrm{\&Delta;}}_{12}\\ {{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^1={{\mathrm{<figure-callout\; id="2"\; label="Z\; c"\; filenames="111215073027.png,111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^2+{\mathrm{\&Delta;}}_{12}\\ {\mathrm{\&Delta;}}_{12}={\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="111215073031.png"\; state="\{\{state\}\}">C</figure-callout>}}_1\\ {\mathrm{\&Delta;}}_{13}=C_2\end{array}\right.---\left(0.6\right)$

$\left\{\begin{array}{c}{{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{\&perp;}}^1=\frac{{Z_c}^1}{f/\mathrm{dy}}\\ {{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{\&perp;}}^2=\frac{{Z_c}^2}{f/\mathrm{dy}}\\ {{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{\&perp;}}^3=\frac{{Z_c}^3}{f/\mathrm{<figure-callout\; id="1"\; label="dy\; Z\; c"\; filenames="111215073031.png"\; state="\{\{state\}\}">dy</figure-callout>}}& \\ {Z_c}^{}{{}_{}}^1={{\mathrm{<figure-callout\; id="2"\; label="Z\; c"\; filenames="111215073027.png,111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^2+{\mathrm{\&Delta;}}_{12}\\ {{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^1={{\mathrm{<figure-callout\; id="2"\; label="Z\; c"\; filenames="111215073027.png,111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^2+{\mathrm{\&Delta;}}_{12}\\ {\mathrm{\&Delta;}}_{12}={\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="111215073031.png"\; state="\{\{state\}\}">C</figure-callout>}}_1\\ {\mathrm{\&Delta;}}_{13}=C_2\end{array}\right.---\left(0.7\right)$

Find the solution the approximate solution that overdetermined equation group (0.6) can obtain parameter f/dx, find the solution the approximate solution that overdetermined equation group (0.7) can obtain parameter f/dy, circular feature point P ₀Be an ellipse after the imaging, choose the measurement ratio that is parallel to the diameter calculated characteristics point place horizontal direction of imaging plane on the circle

According to formula (0.5) can obtain the sampling coordinate at flag sign point place

Further, in the step (3), the implementation procedure that the settling amount visible sensation method is measured is following: selected P ₁₁Be RP, utilize pixel coordinate and measurement than calculating P ₀Distance between point and RP on the vertical direction, i.e. P ₁₁Point and P ₀Point Yc coordinate difference just can obtain the sedimentation value of measuring point after each compacting;

Set up following system of equations according to formula (0.1) and formula (0.2):

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="11"\; label="v"\; filenames="111215073031.png"\; state="\{\{state\}\}">v</figure-callout>}}^{11}=\frac{{Y_c}^{11}}{{{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^1}\&CenterDot;f/\mathrm{dy}+v_0\\ {\mathrm{<figure-callout\; id="12"\; label="v"\; filenames="111215073017.png,111215073031.png"\; state="\{\{state\}\}">v</figure-callout>}}^{12}=\frac{{Y_c}^{12}}{{{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^1}\&CenterDot;f/\mathrm{dy}+v_0\\ {Y_c}^{12}=f\left({Y_c}^{11}\right)\\ ......\end{array}\right.---\left(0.8\right)$

The group of solving an equation (0.8) can get parameter

(j=1,2 ... 12) and parameter v ₀, substitution formula (0.9) can be to parameter

Find the solution,

$v^0=\frac{{Y_c}^0}{{Z_c}^0}\&CenterDot;f/\mathrm{dy}+v_0---\left(0.9\right)$

So, the sedimentation measuring point, flag sign point P just samples ₀With RP P ₁₁At Y _cThe coordinate difference does on the axle

Be the distance of in the vertical direction between measuring point and RP, roadbed is again through after the compacting, with obtain a new distance value Δ ', after twice compacting, the subgrade settlement amount be Δ '-Δ.

Further; In the step (4), in the compactness measuring process, because water environment, the particle voids of soil change; The dry density and the wet density of soil all change before and after the compacting operation; But the nt wt net weight of shop layer soil satisfies the mass conservation, does not change before and after the compacting operation, promptly has following formula to set up:

h′·s·ρ _d′＝h·s·ρ _d

In the formula:

Shop layer thickness before h---the compacting operation, cm;

ρ _d---dry density before the compacting operation, kg/m ³

H '---through spreading layer thickness, cm after the compacting;

ρ _d'---through layer dry density in shop after the compacting, kg/m ³

S---shop layer thickness area, m ²

Then, can calculate compactness according to following formula:

$K^{\&prime;}=K\&CenterDot;\frac{h}{h-\mathrm{\&Delta;}}---\left(0.10\right)$

In the formula:

Shop layer thickness before h---the compacting operation, cm;

Δ---through the settling amount after the compacting, cm;

The compactness of shop layer before K---the compacting operation;

K '---through the compactness after the compacting;

Shop layer thickness aerial controlled variable when being roadbed; Initial compactness is measured with traditional method, and the settling amount that initial compactness, shop layer thickness and step (3) are calculated is brought formula (0.10) into and can be calculated through the new compactness of roadbed behind compacting operation.

3. beneficial effect

Adopt technical scheme provided by the invention, compare, have following remarkable result with existing known technology:

(1) a kind of Subgrade Compaction online test method of the present invention based on machine vision; Against existing technologies one, the present invention, is stored in the computing machine as detecting and the carrier of the information of transmission with image; Can realize online detection; Avoided the error that manually-operated brought, reduced labour intensity, video information capable of using in addition instructs safe construction;

(2) a kind of Subgrade Compaction online test method of the present invention based on machine vision; Against existing technologies two, the present invention meets people's law of cognition, realizes people's visual performance with computing machine and utility appliance; Thereby realize through the numerical value of shop layer after the two dimensional image perception compacting each time with respect to sedimentation after the compacting last time; The increase of sedimentation means the increase of soil layer compaction rate, has avoided the deficiency of prior art two, does not promptly disclose vibrating compacting mechanism at present as yet fully; People are not comprehensive to the understanding of vibrating wheels acceleration signal, still can not explain the abnormal conditions of acceleration signal;

(3) a kind of Subgrade Compaction online test method of the present invention based on machine vision; Against existing technologies three; Detection limit of the present invention is that shop layer is with respect to compacting sedimentation value last time after the compacting each time, and sedimentation increases and characterizes the soil layer compaction rate and increase not polysemy, so the compact technique that is adopted in detection method and the construction is separate; The subgrade compaction operation that this detection method goes for new method detects, and is applicable to vibroll unlike prior art three;

(4) the present invention detects and the transmission information carrier, can obtain the compactness with the data accurate description, and data storage helps to preserve construction information on calculating;

(5) the present invention has realized the online detection of Subgrade Compaction, thereby has improved compacting operation quality and operating efficiency;

(6) accuracy of detection of the present invention is mainly relevant with the model accuracy of setting up, and need not do special processing to moving with the location of camera;

(7) the present invention suitably increases marker peg quantity, can realize the online detection in long distance construction highway section.

Description of drawings

Vibroll-soil the mathematical model that obtains based on a series of hypothesis in the paper that Fig. 1 writes for prosperous mountain etc.;

Fig. 2 is that disclosed harmonic ratio HVR increases the curve map that changes in the prior art three along with compacting counting;

Fig. 3 is the synoptic diagram of vision testing system of the present invention;

Fig. 4 is a marker peg three-decker synoptic diagram of the present invention;

Fig. 5 is the present invention program's a imaging model.

Label declaration in the synoptic diagram:

The 1-CCD camera; 2-sampling flag sign point; The 3-marker peg.

Embodiment

Below in conjunction with accompanying drawing the present invention is done further description.

As shown in Figure 3, vision measurement system is made up of 1 CCD camera, 1 marker peg and 1 compactness sampling flag sign point, needs to measure a plurality of compactness sampled points, the quantity of corresponding increase marker peg and sampling flag sign number of spots.Marker peg is a three-decker, and every layer is " ten " font, but size is different, as shown in Figure 4.Need three layers of assurances parallel during marker peg is made, marker peg needs to guarantee that the face of " ten " word is vertical with the road surface when installing.Sampling flag sign point is for circular, and size is not done special demands, and the mode of available paint spraying realizes.

Shown in Figure 5 is the mathematical model of this measuring system, wherein O _c-X _cY _cZ _cBe camera coordinates system, O _cBe camera photocentre, Z _cAxle and camera optical axis coincidence are got world coordinate system (O _w-X _wY _wZ _w) overlap with camera coordinates system, I is the picture plane, and O-XY is image physical coordinates system, and o-uv is the image pixel coordinate system, P _IjBe face _i(i=1,2,3) last j angle point (j=1,2 ..., 12), corresponding picture point is used P _Ij' expression, P ₀Be artificial target's unique point, be the measuring point of settling amount, picture point is designated as P ₀'.

Below in conjunction with embodiment the present invention is done further description.

Embodiment

A kind of Subgrade Compaction online test method based on machine vision of present embodiment the steps include:

(1) set up vision measurement system:

The compactness of a compactness sampled point is measured, and its measuring system is made up of 1 CCD camera, 1 sampling flag sign point and 1 marker peg, and wherein, marker peg amounts to and divides three layers, and every layer is " ten " font, is designated as face from left to right respectively ₁, face ₂With face ₃, the angle point of these three faces is labeled as 1,2 successively, 3..., 12;

Marker peg in the step (1) is arranged near the compactness sampled point, this compactness sampled point and marker peg within the visual field of CCD camera, wherein, marker peg be arranged in construction section along the line on, face ₁, face ₂With face ₃Be parallel to each other face ₁Perpendicular with the construction road surface; Compactness sampling flag sign point is the mode through spray paint, at road surfaces compactness sample point spraying circle marker as unique point.

(2) Flame Image Process:

The CCD camera is gathered the compacting image scene, extracts three layers of image coordinate that amounts to 36 points of marker peg then, and match obtains three " ten " fonts of marker peg; Extract the image coordinate of sampling flag sign dot center and oval major semi-axis and the oval minor semi-axis Pixel Dimensions size parameter after the imaging of circular sampling flag sign point;

In the imaging model of step (2) Flame Image Process, establish O _c-X _cY _cZ _cBe CCD camera coordinates system, O _cBe CCD camera photocentre, Z _cAxle and CCD camera optical axis coincidence are with world coordinate system (O _w-X _wY _wZ _w) overlap with CCD camera coordinates system, I is the picture plane, and O-XY is image physical coordinates system, and o-uv is the image pixel coordinate system, P _IjBe face _i(i=1,2,3) last j angle point (j=1,2 ..., 12), corresponding picture point is used P _Ij' expression, P ₀Be artificial target's compactness sampling flag sign point, be the measuring point of settling amount, picture point is designated as P ₀'; Set following parameter or geometric condition:

A) P _IjAt O _c-X _cY _cZ _cOn coordinate use

Expression;

B) P _Ij' coordinate on image coordinate system O-XY is with (X ^Ij, Y ^Ij) expression;

C) P _Ij' be that coordinate on the o-uv is with (u at pixel coordinate ^Ij, v ^Ij) expression;

D) focal length of camera is represented with f;

E) pixel is respectively dx and dy at imaging plane X and Y direction size;

F) coordinate of the initial point of coordinate system O-XY on image pixel coordinate system o-uv is (u ₀, v ₀);

G) if line segment p _Ijp _Ij+1In camera coordinates system is vertical direction, so p _Ij+1p _Ij+2Horizontal direction must be in, p might as well be supposed _Ijp _Ij+1Line segment for vertical direction in the camera coordinates system;

Get P _Ij, P _Ij+1And P _Ij+2Three points, in conjunction with imaging model, its imaging process is following:

According to the pinhole imaging system principle, obtain following equality and set up:

$\left\{\begin{array}{c}{X}^{\mathrm{ij}}=f\&CenterDot;({X_c}^{\mathrm{ij}}/{Z_c}^i)\\ Y^{\mathrm{ij}}=f\&CenterDot;({Y_c}^{\mathrm{ij}}/{Z_c}^i)\end{array}\right.---\left(0.1\right)$

$\left\{\begin{array}{c}{u}^{\mathrm{ij}}=X^{\mathrm{ij}}/\mathrm{dx}+u_0\\ v^{\mathrm{ij}}=Y^{\mathrm{ij}}/\mathrm{dy}+v_0\end{array}\right.---\left(0.2\right)$

Note point P _IjWith a P _Ij+1Distance between two points is l ₁, some P _Ij' and some P _Ij+12 pel spacings are from being l ₁', then have:

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="111215073031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1={Y_c}^{\mathrm{ij}}-{Y_c}^{\mathrm{ij}+1}\\ {\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="111215073031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1^{\&prime;}=v^{\mathrm{ij}}-v^{\mathrm{ij}+1}=\frac{f}{\mathrm{dy}}\&CenterDot;\frac{{Y_c}^{\mathrm{ij}}-{Y_c}^{\mathrm{ij}+1}}{{Z_c}^i}\end{array}\right.---\left(0.3\right)$

β is compared in the measurement of definition vertical direction _⊥:

${\mathrm{\&beta;}}_{\&perp;}=\frac{l_1}{{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="111215073031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1^{\&prime;}}=\frac{{Z_c}^i}{f/\mathrm{dy}}---\left(0.4\right)$

β is compared in the measurement that can define horizontal direction equally _-:

${\mathrm{\&beta;}}_{-}=\frac{{Z_c}^i}{f/\mathrm{dx}}---\left(0.5\right)$

Above-mentioned measurement is than being to be used for the physical quantity that the characterization of visual measuring system concerns between given distance testee physical dimension and Pixel Dimensions;

Face ₁There are six to be parallel to X _cThe limit of axle is horizontal sides, can obtain the measurement ratio of six horizontal directions after the imaging, with the mean value of the measurement ratio of six horizontal directions as face ₁The measurement ratio of position horizontal direction is used symbol

Expression, same, can obtain face ₂The measurement ratio of position horizontal direction

Face ₃The measurement ratio of position horizontal direction

Face ₁There are six to be parallel to Y _cThe limit of axle is vertical edge, can obtain the measurement ratio of six vertical directions after the imaging, too with the method for averaging, calculates the that appears ₁The measurement ratio of position vertical direction

In like manner, get face ₂The measurement ratio of position vertical direction

Face ₃Vertical square of position to the measurement ratio

During Flame Image Process: measure face with vernier caliper ₁, face ₂And face ₃Go up " ten " length on all limits of font, and carry out Flame Image Process and obtain face ₁, face ₂And face ₃Go up that " ten " length in pixels on all limits of font calculates face ₁The measurement ratio of position horizontal direction

Face ₂The measurement ratio of position horizontal direction

Face ₃The measurement ratio of position horizontal direction; Face ₁The measurement ratio of position vertical direction

Face ₂The measurement ratio of position vertical direction

Face ₃Vertical square of position to the measurement ratio

The note Δ ₁₂And Δ ₁₃Be two process variable, represent the distance between first cross and second cross respectively, and the distance between first cross and the thirty word; C1 representes the variable Δ ₁₂Value; C2 representes the variable Δ ₁₃Value, then have:

$\left\{\begin{array}{c}{{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{-}}^1=\frac{{Z_c}^1}{f/\mathrm{dx}}\\ {{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{-}}^2=\frac{{Z_c}^2}{f/\mathrm{dx}}\\ {{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{-}}^3=\frac{{Z_c}^3}{f/\mathrm{<figure-callout\; id="1"\; label="dx\; Z\; c"\; filenames="111215073031.png"\; state="\{\{state\}\}">dx</figure-callout>}}& \\ {Z_c}^{}{{}_{}}^1={{\mathrm{<figure-callout\; id="2"\; label="Z\; c"\; filenames="111215073027.png,111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^2+{\mathrm{\&Delta;}}_{12}\\ {{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^1={{\mathrm{<figure-callout\; id="2"\; label="Z\; c"\; filenames="111215073027.png,111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^2+{\mathrm{\&Delta;}}_{12}\\ {\mathrm{\&Delta;}}_{12}={\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="111215073031.png"\; state="\{\{state\}\}">C</figure-callout>}}_1\\ {\mathrm{\&Delta;}}_{13}=C_2\end{array}\right.---\left(0.6\right)$

$\left\{\begin{array}{c}{{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{\&perp;}}^1=\frac{{Z_c}^1}{f/\mathrm{dy}}\\ {{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{\&perp;}}^2=\frac{{Z_c}^2}{f/\mathrm{dy}}\\ {{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{\&perp;}}^3=\frac{{Z_c}^3}{f/\mathrm{<figure-callout\; id="1"\; label="dy\; Z\; c"\; filenames="111215073031.png"\; state="\{\{state\}\}">dy</figure-callout>}}& \\ {Z_c}^{}{{}_{}}^1={{\mathrm{<figure-callout\; id="2"\; label="Z\; c"\; filenames="111215073027.png,111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^2+{\mathrm{\&Delta;}}_{12}\\ {{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^1={{\mathrm{<figure-callout\; id="2"\; label="Z\; c"\; filenames="111215073027.png,111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^2+{\mathrm{\&Delta;}}_{12}\\ {\mathrm{\&Delta;}}_{12}={\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="111215073031.png"\; state="\{\{state\}\}">C</figure-callout>}}_1\\ {\mathrm{\&Delta;}}_{13}=C_2\end{array}\right.---\left(0.7\right)$

Measure face with vernier caliper ₁, face ₂, face ₃Between distance, in conjunction with the measurement ratio that calculates, find the solution the approximate solution that overdetermined equation group (0.6) can obtain parameter f/dx, find the solution the approximate solution that overdetermined equation group (0.7) can obtain parameter f/dy, the circular feature point P of known diameter ₀Be an ellipse after the imaging, obtain oval major semi-axis image length, minor semi-axis image length and oval heart image coordinate, P through Flame Image Process ₀Diameter and oval major semi-axis ratio be the measurement ratio of unique point place horizontal direction

According to formula (0.5) can obtain the sampling coordinate at flag sign point place

(3) settling amount calculates:

Full-size(d) and picture size according to " ten " font full-size(d) and picture size and sampling flag sign point; Calculate sampling flag sign dot center to the vertical range between the selected RP of marker peg; Previous with it vertical range is compared, and obtains the settling amount of this compacting operation;

In the step (3), the implementation procedure that the settling amount visible sensation method is measured is following: selected P ₁₁Be RP, utilize pixel coordinate and measurement than calculating P ₀Distance between point and RP on the vertical direction, i.e. P ₁₁Point and P ₀Point Yc coordinate difference just can obtain the sedimentation value of measuring point after each compacting;

Set up following system of equations according to formula (0.1) and formula (0.2):

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="11"\; label="v"\; filenames="111215073031.png"\; state="\{\{state\}\}">v</figure-callout>}}^{11}=\frac{{Y_c}^{11}}{{{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^1}\&CenterDot;f/\mathrm{dy}+v_0\\ {\mathrm{<figure-callout\; id="12"\; label="v"\; filenames="111215073017.png,111215073031.png"\; state="\{\{state\}\}">v</figure-callout>}}^{12}=\frac{{Y_c}^{12}}{{{\mathrm{<figure-callout\; id="1"\; label="Z\; c"\; filenames="111215073031.png"\; state="\{\{state\}\}">Z</figure-callout>}}_c}^1}\&CenterDot;f/\mathrm{dy}+v_0\\ {Y_c}^{12}=f\left({Y_c}^{11}\right)\\ ......\end{array}\right.---\left(0.8\right)$

The group of solving an equation (0.8) can get parameter

(j=1,2 ... 12) and parameter v ₀, substitution formula (0.9) can be to parameter

Find the solution,

$v^0=\frac{{Y_c}^0}{{Z_c}^0}\&CenterDot;f/\mathrm{dy}+v_0---\left(0.9\right)$

If selected P ₁₁Be RP, unique point P ₀With P ₁₁At Y _cThe coordinate difference does on the axle Be the distance of in the vertical direction between measuring point and RP.Roadbed is again through after the compacting, and with obtaining a new distance value Delta2, after twice compacting, the subgrade settlement amount is Δ=Delta2-Delta1.

(4) Subgrade Compaction is calculated:

Settling amount substitution settling amount-compactness mathematical model with step (3) obtains can calculate the new compactness of roadbed; In the step (4), calculate compactness according to following formula:

$K^{\&prime;}=K\&CenterDot;\frac{h}{h-\mathrm{\&Delta;}}---\left(0.10\right)$

In the formula:

Shop layer thickness before h---the compacting operation, cm;

Δ---through the settling amount after the compacting, cm;

The compactness of shop layer before K---the compacting operation;

K '---through the compactness after the compacting;

Measure new settlement values; Under shop layer thickness before known this compacting operation and the compactness two parameter conditions; Can calculate the new compactness of roadbed behind this compacting operation according to settling amount-compactness mathematical modulo pattern (0.10), initial compactness is measured with traditional method.

A kind of Subgrade Compaction online test method of the present invention based on machine vision; Be a kind of brand-new, based on machine vision, online Subgrade Compaction detection method; Its unique distinction is: be to detect and transmit information carrier with the image; When obtaining compactness, image data storage helps to preserve construction information on calculating.Separate between detection method and the compact technique, the compacting operation that this method can be applicable to different debulking methods or different compacting equipment detects.

Claims (5)

1. the Subgrade Compaction online test method based on machine vision the steps include:

(1) set up vision measurement system:

The compactness of a compactness sampled point is measured; Its measuring system is made up of 1 CCD camera, 1 sampling flag sign point and 1 marker peg, when a plurality of compactness sampled points are sampled, and then corresponding increase sampling flag sign point and marker peg quantity; Wherein, Marker peg amounts to and divides three layers, and every layer is " ten " font, is designated as face from left to right respectively ₁, face ₂With face ₃, the angle point of these three faces is labeled as 1,2 successively, 3..., 12;

(2) Flame Image Process:

The CCD camera is gathered the compacting image scene, extracts three layers of image coordinate that amounts to 36 points of marker peg then, and match obtains three " ten " fonts of marker peg; Extract the image coordinate of sampling flag sign dot center and oval major semi-axis and the oval minor semi-axis Pixel Dimensions size parameter after the imaging of circular sampling flag sign point;

(3) settling amount calculates:

Full-size(d) and picture size according to " ten " font full-size(d) and picture size and sampling flag sign point; Calculate sampling flag sign dot center to the vertical range between the selected RP of marker peg; Previous with it vertical range is compared, and obtains the settling amount of this compacting operation;

(4) Subgrade Compaction is calculated:

Settling amount substitution settling amount-compactness mathematical model with step (3) obtains can calculate the new compactness of roadbed.

2. a kind of Subgrade Compaction online test method according to claim 1 based on machine vision; It is characterized in that: the marker peg in the step (1) is arranged near the compactness sampled point; This compactness sampled point and marker peg are within the visual field of CCD camera; Wherein, marker peg be arranged in construction section along the line on, face ₁, face ₂With face ₃Be parallel to each other face ₁Perpendicular with the construction road surface; Compactness sampling flag sign point is the mode through spray paint, at road surfaces compactness sample point spraying circle marker as unique point.

3. a kind of Subgrade Compaction online test method based on machine vision according to claim 2 is characterized in that: in the imaging model of step (2) Flame Image Process, establish O _c-X _cY _cZ _cBe CCD camera coordinates system, O _cBe CCD camera photocentre, Z _cAxle and CCD camera optical axis coincidence are with world coordinate system (O _w-X _wY _wZ _w) overlap with CCD camera coordinates system, I is the picture plane, and O-XY is image physical coordinates system, and o-uv is the image pixel coordinate system, P _IjBe face _i(i=1,2,3) last j angle point (j=1,2 ..., 12), corresponding picture point is used P _Ij' expression, P ₀Be artificial target's compactness sampling flag sign point, be the measuring point of settling amount, picture point is designated as P ₀'; Set following parameter or geometric condition:

A) P _IjAt O _c-X _cY _cZ _cOn coordinate use

Expression;

B) P _Ij' coordinate on image coordinate system O-XY is with (X ^Ij, Y ^Ij) expression;

C) P _Ij' be that coordinate on the o-uv is with (u at pixel coordinate ^Ij, v ^Ij) expression;

D) focal length of camera is represented with f;

E) pixel is respectively dx and dy at imaging plane X and Y direction size;

F) coordinate of the initial point of coordinate system O-XY on image pixel coordinate system o-uv is (u ₀, v ₀);

G) if line segment p _Ijp _Ij+1In camera coordinates system is vertical direction, so p _Ij+1p _Ij+2Horizontal direction must be in, p might as well be supposed _Ijp _Ij+1Line segment for vertical direction in the camera coordinates system;

Get P _Ij, P _Ij+1And P _Ij+2Three points, in conjunction with imaging model, its imaging process is following:

According to the pinhole imaging system principle, obtain following equality and set up:

$\left\{\begin{array}{c}{X}^{\mathrm{ij}}=f\&CenterDot;({X_c}^{\mathrm{ij}}/{Z_c}^i)\\ Y^{\mathrm{ij}}=f\&CenterDot;({Y_c}^{\mathrm{ij}}/{Z_c}^i)\end{array}\right.---\left(0.1\right)$

$\left\{\begin{array}{c}{u}^{\mathrm{ij}}=X^{\mathrm{ij}}/\mathrm{dx}+u_0\\ v^{\mathrm{ij}}=Y^{\mathrm{ij}}/\mathrm{dy}+v_0\end{array}\right.---\left(0.2\right)$

Note point P _IjWith a P _Ij+1Distance between two points is l ₁, some P _Ij' and some P _Ij+12 pel spacings are from being l ₁', then have:

$\left\{\begin{array}{c}{l}_1={Y_c}^{\mathrm{ij}}-{Y_c}^{\mathrm{ij}+1}\\ l_1^{\&prime;}=v^{\mathrm{ij}}-v^{\mathrm{ij}+1}=\frac{f}{\mathrm{dy}}\&CenterDot;\frac{{Y_c}^{\mathrm{ij}}-{Y_c}^{\mathrm{ij}+1}}{{Z_c}^i}\end{array}\right.---\left(0.3\right)$

β is compared in the measurement of definition vertical direction _⊥:

${\mathrm{\&beta;}}_{\&perp;}=\frac{l_1}{l_1^{\&prime;}}=\frac{{Z_c}^i}{f/\mathrm{dy}}---\left(0.4\right)$

β is compared in the measurement that can define horizontal direction equally _-:

${\mathrm{\&beta;}}_{-}=\frac{{Z_c}^i}{f/\mathrm{dx}}---(0.1)$

Above-mentioned measurement is than being to be used for the physical quantity that the characterization of visual measuring system concerns between given distance testee physical dimension and Pixel Dimensions;

Face ₁There are six to be parallel to X _cThe limit of axle is horizontal sides, can obtain the measurement ratio of six horizontal directions after the imaging, with the mean value of the measurement ratio of six horizontal directions as face ₁The measurement ratio of position horizontal direction is used symbol

Expression, same, can obtain face ₂The measurement ratio of position horizontal direction

Face ₃The measurement ratio of position horizontal direction

Face ₁There are six to be parallel to Y _cThe limit of axle is vertical edge, can obtain the measurement ratio of six vertical directions after the imaging, too with the method for averaging, calculates the that appears ₁The measurement ratio of position vertical direction

In like manner, get face ₂The measurement ratio of position vertical direction

Face ₃Vertical square of position to the measurement ratio

Δ ₁₂And Δ ₁₃Be two process variable, represent the distance between first cross and second cross respectively, and the distance between first cross and the thirty word; C1 representes the variable Δ ₁₂Value; C2 representes the variable Δ ₁₃Value, then have:

$\left\{\begin{array}{c}{{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{-}}^1=\frac{{Z_c}^1}{f/\mathrm{dx}}\\ {{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{-}}^2=\frac{{Z_c}^2}{f/\mathrm{dx}}\\ {{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{-}}^3=\frac{{Z_c}^3}{f/\mathrm{dx}}\\ {Z_c}^1={Z_c}^2+{\mathrm{\&Delta;}}_{12}\\ {Z_c}^1={Z_c}^2+{\mathrm{\&Delta;}}_{12}\\ {\mathrm{\&Delta;}}_{12}=C_1\\ {\mathrm{\&Delta;}}_{13}=C_2\end{array}\right.---\left(0.6\right)$

$\left\{\begin{array}{c}{{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{\&perp;}}^1=\frac{{Z_c}^1}{f/\mathrm{dy}}\\ {{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{\&perp;}}^2=\frac{{Z_c}^2}{f/\mathrm{dy}}\\ {{\stackrel{\&OverBar;}{\mathrm{\&beta;}}}_{\&perp;}}^3=\frac{{Z_c}^3}{f/\mathrm{dy}}\\ {Z_c}^1={Z_c}^2+{\mathrm{\&Delta;}}_{12}\\ {Z_c}^1={Z_c}^2+{\mathrm{\&Delta;}}_{12}\\ {\mathrm{\&Delta;}}_{12}=C_1\\ {\mathrm{\&Delta;}}_{13}=C_2\end{array}\right.---\left(0.7\right)$

Find the solution the approximate solution that overdetermined equation group (0.6) can obtain parameter f/dx, find the solution the approximate solution that overdetermined equation group (0.7) can obtain parameter f/dy, circular feature point P ₀Be an ellipse after the imaging, choose the measurement ratio that is parallel to the diameter calculated characteristics point place horizontal direction of imaging plane on the circle According to formula (0.5) can obtain the sampling coordinate at flag sign point place

4. a kind of Subgrade Compaction online test method based on machine vision according to claim 3 is characterized in that: in the step (3), the implementation procedure that the settling amount visible sensation method is measured is following: selected P ₁₁Be RP, utilize pixel coordinate and measurement than calculating P ₀Distance between point and RP on the vertical direction, i.e. P ₁₁Point and P ₀Point Yc coordinate difference just can obtain the sedimentation value of measuring point after each compacting;

Set up following system of equations according to formula (0.1) and formula (0.2):

$\left\{\begin{array}{c}{v}^{11}=\frac{{Y_c}^{11}}{{Z_c}^1}\&CenterDot;f/\mathrm{dy}+v_0\\ v^{12}=\frac{{Y_c}^{12}}{{Z_c}^1}\&CenterDot;f/\mathrm{dy}+v_0\\ {Y_c}^{12}=f\left({Y_c}^{11}\right)\\ ......\end{array}\right.---\left(0.8\right)$

The group of solving an equation (0.8) can get parameter

(j=1,2 ... 12) and parameter v ₀, substitution formula (0.9) can be to parameter

Find the solution,

$v^0=\frac{{Y_c}^0}{{Z_c}^0}\&CenterDot;f/\mathrm{dy}+v_0---\left(0.9\right)$

So, the sedimentation measuring point, flag sign point P just samples ₀With RP P ₁₁At Y _cThe coordinate difference does on the axle Be the distance of in the vertical direction between measuring point and RP, roadbed is again through after the compacting, with obtain a new distance value Δ ', after twice compacting, the subgrade settlement amount be Δ '-Δ.

5. a kind of Subgrade Compaction online test method based on machine vision according to claim 4 is characterized in that: in the step (4), calculate compactness according to following formula:

$K^{\&prime;}=K\&CenterDot;\frac{h}{h-\mathrm{\&Delta;}}---\left(0.10\right)$

In the formula:

Shop layer thickness before h---the compacting operation, cm;

Δ---through the settling amount after the compacting, cm;

The compactness of shop layer before K---the compacting operation;

K '---through the compactness after the compacting;

Shop layer thickness aerial controlled variable when being roadbed; Initial compactness is measured with traditional method, and the settling amount that initial compactness, shop layer thickness and step (3) are calculated is brought formula (0.10) into and can be calculated through the new compactness of roadbed behind compacting operation.

Images