CN102062582B - Method for measuring length of continuous-casting steel blank by camera and device thereof - Google Patents

Abstract

The invention relates to a method for measuring length of a continuous-casting steel blank by a camera and a device thereof, belonging to the technical field of metallurgy. In a length measurement system formed by a camera and a computer, and length measurement comprises the following steps: establishing a corresponding relationship table of a steel blank surface average temperature which is acquired by testing and the stop number of the camera in the computer; calculating the average temperature of the steel blank head surface by the computer according to a formula according to input slab thickness, time step, molten steel heat conductivity, molten steel density and molten steel thermal capacity; searching a corresponding image aperture parameter from the relationship table by the computer according to the calculated average temperature of the steel blank head surface, and transmitting the corresponding image aperture parameter to an aperture controller through a communication wire so as to drive an aperture motor and adjust the aperture of the camera; and identifying the position of the continuous-casting steel blank head by the computer through imaging processing according to input camera video data so as to acquire a length measurement result. The method overcomes the defects of unclear imaging of the steel blank caused by uneven heat and cold of the steel blank, reduces interference of external factors, reduces manual intervention degree, and ensures the length measurement accuracy of the continuous-casting steel blank.

Description

Rectangular method and device are surveyed in the continuous casting steel billet shooting

Technical field

The present invention relates to a kind of rectangular method of survey of steel billet, rectangular method and device are surveyed in especially a kind of continuous casting steel billet shooting, belong to metallurgical technology field.

Background technology

In the steel-making continuous casting producing process flow process, the online length detection of continuous casting steel billet and scale cutting are important steps wherein, and the control accuracy of steel billet cutting directly has influence on the lumber recovery of continuous casting steel billet.Traditional conticaster adopts the measuring roller that has scrambler to carry out steel billet linear measure longimetry (being called mechanical type surveys long); Because this length measurement system leans on the friction force between measuring roller and the continuous casting steel billet to drive; Be subject to the influence of factors such as on-the-spot high temperature, steel billet distortion, cause that this measurement mechanism maintenance is big, control accuracy is unstable.

The shooting length measurement system with video camera as detecting element; Send the steel billet image of gathering to computing machine; Utilize image processing techniquess such as curve fitting to carry out smoothing processing; Interference component in the rejection image (steam, sunlight, electric welding light etc.) is accurately discerned the continuous casting steel billet head position to the influence of normal steel billet imaging, accomplishes detect length of billets (referring to Fig. 1).This will, the system that engages of image processing techniques and steel billet cutting, can accomplish continuous casting steel billet cutting control, have non-contact detecting, maintenance little, detect accurately height, control accuracy and characteristics such as stablize, adopted by increasing iron and steel enterprise.

Accuracy of detection is not high, the control accuracy problem of unstable but the detection at positions such as the steel billet lapping defect that existing shooting survey length causes the anomalous event in the steel-making continuous casting casting cycle, sub-cooled also exists.The main cause that causes this situation is that video camera is after debugging finishes; Focal length, aperture just are fixed up, though can satisfy the control requirement of the steel billet length detection precision under the normal condition, under abnormal conditions; The detection of different brightness steel billets; Then need manual intervention,, satisfy the length detection of different brightness steel billets under the specific operation through the mode of computer picture manual adjustments camera aperture.The result certainly will increase operative employee's manipulation strength, and accuracy of detection is unstable.Therefore, managing to make shooting to survey length, can to adapt to the length detection of different brightness steel billets automatically very crucial.

Adopt auto iris video camera effect not ideal enough, main cause is its shooting focus point relative fixed.Induction with an automatic light meter be that whole brightness changes, can receive also that external interference such as track are reflective, steam, the influence of factor such as shine upon, and shooting is surveyed the long steel billet head brightness that only needs accurately to follow the tracks of constantly motion and is changed.

Retrieval finds that related patent U.S. Patent No. is following: 1, application number is that 88105869 Chinese patent discloses a kind of " detect length of billets method and device "; The characteristics of this method are that self light with hot steel billet is signal source; The CCD photosensitive imaging becomes vision signal with light signal; Vision signal is carried out " binaryzation " handle, the signal after handling is carried out mould/number conversion, sample automatically and data processing with microprocessor; The patent No. is that the characteristics that 97102342.5 Chinese patent discloses " method of measuring real space length by camera shooting and optical system correction method and regional master gage thereof " this method are the average real space lengths through a pixel of micrometric measurement; And measure or the adjustment image pickup scope, can measure pattern distortion and reach optical system correction by its correction image distortion as a result.In addition, Jap.P. JP2000266516 discloses surface accurate detection method after a kind of steel billet joint treatment, JP02160153A and discloses through the ladle slide gate in billet camera monitoring, improved and connect the method for watering the binding site tracking accuracy.These all do not relate to shooting and survey the counter-measure that the long steel billet section brightness that cancel closedown etc. causes in to casting process changes.

Summary of the invention

The objective of the invention is to: propose a kind of can be under abnormal conditions, thereby guarantee that according to steel billet head brightness regulation camera aperture parameter the continuous casting steel billet shooting of steel billet length detection precision surveys rectangular method automatically, provide corresponding device thereof simultaneously.

In order to reach above purpose; Continuous casting steel billet shooting of the present invention is surveyed rectangular method in the length measurement system that is made up of video camera and computing machine; The video line of said camera lens and aperture controller is connected with the corresponding interface of computing machine through plug respectively with connection, in order to transmitting video data and communication information; The control output end of said aperture controller connects the controlled end of camera aperture motor; It is following to it is characterized in that surveying long step:

The first step, the foundation test obtains in computing machine steel billet head surface temperature and camera light number of turns mapping table;

Second step, computing machine are according to the slab thickness of importing, time step, molten steel coefficient of heat conductivity molten steel density, molten steel thermal capacitance and initial steel billet central temperature, average surface temperature and intensity of cooling; By following formula, calculate steel billet head surface medial temperature in proper order:

$T_2^{p+1}=T_1^p+\frac{2\mathrm{\Δtk}\left(T_1^p\right)}{{\left(\mathrm{\Δx}\right)}^2\mathrm{\ρc}}(T_2^p-T_1^p)-\mathrm{\Δtq}/\left(\mathrm{\Δx\ρc}\right)$

In the following formula: P---the step-length number is natural number 1,2,3,4...

T ₂ ^P+1---the billet surface medial temperature that time step P+1 is corresponding, degree centigrade;

T ₁ ^p---the steel billet central temperature that time step P is corresponding, degree centigrade;

T ₂ ^p---the billet surface medial temperature that time step P is corresponding, degree centigrade;

Δ t---time step (second);

K---molten steel coefficient of heat conductivity;

Δ x---space step-length (millimeter);

ρ---molten steel density (kg/m ³);

C---molten steel thermal capacitance (kCal/kg ℃);

Q---intensity of cooling (kCal)

Preceding two result of calculations in the above formula are the corresponding steel billet central temperature T of time step P+1 ₁ ^P+1Promptly $T_1^{p+1}=T_1^p+\frac{2\mathrm{\Δ\; Tk}\left(T_1^p\right)}{{\left(\mathrm{\Δ\; x}\right)}^2\mathrm{\ρ\; c}}(T_2^p-T_1^p)$

And the corresponding billet surface medial temperature T of time step P+1 ₂ ^P+1Equal the corresponding steel billet central temperature of time step P+1, deduct Δ t*q/ (Δ x* ρ * c).

The 3rd step, computing machine check in corresponding imaging aperture parameters according to the steel billet head surface medial temperature of calculating by said relation table, and are transferred to the aperture controller through connection, and then drive the aperture motor, regulate camera aperture;

The 4th step, computing machine are according to the camera shooting and video data of importing, and through Flame Image Process, identification continuous casting steel billet head position draws and surveys long result.

Like this; Can be according to casting cycle information; The steel billet head surface medial temperature of calculating is converted into the camera aperture data; Be used for controlling image processing system camera aperture size, make clear all the time, the brightness stability of steel billet image that image processing system is gathered, thereby satisfy the requirement that steel billet length accurately detects under the different operating modes.

Continuous casting steel billet shooting measuring motion of the present invention comprises the length measurement system that is made up of video camera and computing machine; The video line of said camera lens and aperture controller is connected with the corresponding interface of computing machine through plug respectively with connection, in order to transmitting video data and communication information; The control output end of said aperture controller connects the controlled end of camera aperture motor; It is characterized in that said computing machine also is used for:

Set up steel billet head surface temperature and camera light number of turns mapping table that test obtains;

According to slab thickness, time step, molten steel coefficient of heat conductivity, molten steel density, molten steel thermal capacitance and initial steel billet central temperature, average surface temperature and the intensity of cooling of input,, calculate steel billet head surface medial temperature in proper order by following formula:

$T_2^{p+1}=T_1^p+\frac{2\mathrm{\Δtk}\left(T_1^p\right)}{{\left(\mathrm{\Δx}\right)}^2\mathrm{\ρc}}(T_2^p-T_1^p)-\mathrm{\Δtq}/\left(\mathrm{\Δx\ρc}\right)$

(the symbol implication is the same in the formula)

According to the steel billet head surface medial temperature of calculating, check in corresponding imaging aperture parameters by said relation table, and be transferred to the aperture controller, and then drive the aperture motor through connection, regulate camera aperture;

According to the camera shooting and video data of input, through Flame Image Process, identification continuous casting steel billet head position draws and surveys long result.

The present invention has rationally realized the function according to steel billet temperature auto-control camera aperture on the basis of original shooting length measurement system.Because camera aperture is regulated and control according to the billet surface medial temperature; Therefore billet surface medial temperature and camera aperture parameter are mapped; Make video camera regulate f-number according to detecting steel billet head zone temperature conditions all the time; Thereby shielded the interference of abnormal conditions, effectively improved the sharpness of steel billet head imaging, guaranteed the accuracy of detection of steel billet length the continuous casting steel billet local luminance.

In a word, it is unintelligible that the present invention has overcome the steel billet imaging that causes owing to steel billet in the casting process is uneven in temperature, reduced the interference of external factor, reduced the manual intervention degree, guaranteed the linear measure longimetry precision of continuous casting steel billet.Steel billet length is reached when setting Cutting Length, issue the cutting instruction, accomplish steel billet cutting control to cutting machine.

Description of drawings

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

Fig. 1 is shooting length measurement system synoptic diagram (S video camera, P steel billet, Q cutting gun, T Flame Image Process among the figure).

Fig. 2 collects for continuous casting casting segment data of the present invention and divides synoptic diagram.

Fig. 3 is that the device of one embodiment of the invention constitutes synoptic diagram.

Fig. 4 is the circuit theory diagrams of Fig. 3 embodiment.

Fig. 5 is the control procedure process flow diagram of Fig. 3 embodiment.

Embodiment

Embodiment one

The long principle of shooting survey of present embodiment is as shown in Figure 1, and video camera S is fixed in production scene conticaster horizontal segment, and over against steel billet P cutting zone, the image scene of collection has fixing field range, and the steel billet image that camera is taken is linear distribution on length.Each pixel is corresponding to a physical location, and concrete corresponding relation can be definite through demarcating.The steel billet head is positioned at the location of pixels X that P orders and can obtains through Flame Image Process among the figure, and the P point can obtain through measuring to the distance L (steel billet length) of cutting gun, so just set up one group of steel billet location of pixels and steel billet length corresponding relation (X, L).Therefore, just can measure the steel billet length that to cut as long as detect the steel billet head position.

It is as shown in Figure 2 that continuous casting casting segment data is collected division; Finishing whole casting section from crystallizer end opening M to horizontal segment is unit with 0.5 meter; Be divided into the N section; In the casting cycle such as the raw data of slab thickness, time step, molten steel coefficient of heat conductivity molten steel density, molten steel thermal capacitance and different steel grade link, information such as bag and cancel closedown is concentrated the database that is input to each section correspondence in the computing machine in the quick change; So that calculate each section billet surface medial temperature, and main event information such as heat seaming position in each section, wrap fast change place etc. greatly.

Continuous casting steel billet shooting measuring motion such as Fig. 3, shown in Figure 4 of present embodiment; In the length measurement system that video camera S and computer PC constitute; The video line of camera lens X3 and aperture controller X5 is connected with the corresponding interface COM1 of computing machine through plug X1 respectively with connection, in order to transmitting video data and communication information.The control output end of aperture controller connects the controlled end of camera aperture motor M 3.PR1 is the aperture potentiometer among Fig. 4.

Particularly, the camera aperture controller is positioned at the front deck of camera, and it mainly contains two functions: the firstth, with input+24V or+12V converts into+5V, supply with lens control circuit and use; The secondth, receive the steering order of sending by system, convert them to the control voltage that drives each associated mechanisms of camera lens, realize that camera lens becomes the operation of aperture, also accomplish aperture potentiometer PR1 value simultaneously and gather and be transformed to corresponding data output.

The change aperture settings control of video camera realizes through serial communication.Computing machine is through serial port COM1; Be connected with signal ground with RXD, TXD among the video camera plug X1 among the figure; Aperture settings value through X1 interface sending computer arrives camera aperture controller X5, and X5 regulates the camera aperture size according to the aperture settings value controlling and driving motor M 3 that receives.

Because recurrent supercooling in the casting cycle, therefore whole casting section situation uneven in temperature occurs through regular meeting, very easily causes the dark zone of steel billet to detect, and bright part overexposure all can influence the detection control of steel billet length.The scope that zone that steel billet is dark and normal region brightness need be regulated aperture is bigger, needs dynamic adjustments, accurately identification steel billet head position.Present embodiment through in the casting process control system to the tracking of billet surface medial temperature, dynamically adjust brightness of image in the image processing system according to the billet surface medial temperature; The camera aperture regulated value is sent in the image processing system by the temperature computation module; Thereby realize the self-regulating function of camera aperture, to adapt to the variation of field condition.Its concrete control procedure is (referring to Fig. 5) as follows:

Step 1: in computing machine, set up mapping table between steel billet head surface temperature and the camera aperture.Under normal detection position,, adopt manual mode to regulate aperture in video camera, make the clear picture that collects the steel billet of different surfaces medial temperature scope.Set up the corresponding relation of interior billet surface medial temperature of different temperatures scope and camera aperture in this way.

Sequence number	Average surface temperature (finish, ℃)	F-number
			1	700	1
2	780	2
			3	850	3
4	890	5
			5	920	11
6	1000	13
			7	-	22

Step 2: with being that unit is divided into the N section to the strand section (secondary cooling zone) between the horizontal segment with 0.5 meter below the conticaster crystallizer; Every section as the separate unit of collecting main event information in the casting cycle; Slab thickness, time step, molten steel coefficient of heat conductivity molten steel density, molten steel thermal capacitance and initial steel billet central temperature, average surface temperature and intensity of cooling according to input; By following formula, calculate steel billet head surface medial temperature in proper order:

$T_2^{p+1}=T_1^p+\frac{2\mathrm{\Δtk}\left(T_1^p\right)}{{\left(\mathrm{\Δx}\right)}^2\mathrm{\ρc}}(T_2^p-T_1^p)-\mathrm{\Δtq}/\left(\mathrm{\Δx\ρc}\right)$

In the following formula: P---the step-length number is natural number 1,2,3,4...

T ₂ ^P+1---the billet surface medial temperature that time step P+1 is corresponding, degree centigrade;

T ₁ ^p---the steel billet central temperature that time step P is corresponding, degree centigrade;

T ₂ ^p---the billet surface medial temperature that time step P is corresponding, degree centigrade;

Δ t---time step (second);

K---molten steel coefficient of heat conductivity;

Δ X---space step-length (millimeter);

ρ---molten steel density (kg/m ³);

C---molten steel thermal capacitance (kCal/kg ℃);

Q---intensity of cooling (kCal)

In the present embodiment, d=1550 ℃ of middle bag temperature T, pulling rate V=1.0 rice/minute, wide cooling water flow of crystallizer: 3000, import and export water temperature difference: 4.9 ℃, each flow of secondary cooling water: W (11)={ 384,181; 821,333,203,447,253,289,139; 273,134}, two cold-zones: Len (7)={ 0.315,2.27,3.047,3.047; 3.52,6.09,11.711}, steel grade: mild carbon steel, liquidus temperature: 1530, solidus temperature: 1494.

Set or detect and to know: the central temperature T of the up-to-date fragment P=1 that has just cast out ₁ ¹=1550 ℃, average surface temperature T ₂ ¹=1550 ℃, space step degree: Δ X=0.5 rice, time step Δ t=Δ X/V=0.5 minute, intensity of cooling is 1031044kCal.

According to coefficient of heat conductivity, molten steel density, the molten steel thermal capacitance of mild carbon steel, can calculate the billet surface medial temperature T of last fragment P=2 ₂ ²It is 1356.48 ℃.Because

$T_1^{p+1}=T_1^p+\frac{2\mathrm{\Δtk}\left(T_1^p\right)}{{\left(\mathrm{\Δx}\right)}^2\mathrm{\ρc}}(T_2^p-T_1^p)$

Therefore, in this process, try to achieve the steel billet central temperature T of P=2 simultaneously ₁ ²It is 1539.17 ℃.

Then, can be in the hope of the billet surface medial temperature T of previous fragment P=3 again ₂ ³=1360.5 ℃, and this section steel billet central temperature T ₁ ³=1535.00 ℃.

Go down in proper order according to this, P=4,5,6...... calculates when arriving the cutting original position and finishes.

Step 3: whether computer judges steel billet head surface temperature value is higher than 1000 ℃ or be not lower than 700 ℃ (it is 800-1000 ℃ that steel billet leaves the normal surface medial temperature scope that casting zone gets into horizontal zone; Only during cancel closedown; Local meeting sub-cooled; And steel billet mainly is the nature temperature drop at horizontal segment, 5 ℃/minute of temperature drop speed average out to).When being higher than 1000 ℃, output minimum aperture value, when being lower than 700 ℃, the input lens speed.Otherwise computing machine is according to the steel billet head surface medial temperature calculated, by said relation table check in the immediate imaging aperture parameters of steel billet head surface medial temperature as aperture output valve (for example result of calculation is 900, then exports 11).

Step 4: computing machine is transferred to the aperture controller through connection with the aperture output valve, and then drives the aperture motor, regulates camera aperture;

Step 5: after the shooting length measurement system is accomplished aperture settings according to the aperture data that receive through the camera aperture control device; Computing machine gets into shooting and surveys long-range order, according to the camera shooting and video data of input, through Flame Image Process; Identification continuous casting steel billet head position draws and surveys long result.

Step 6: computing machine is according to surveying long result, control cutting machine fixed length cutting steel billet.

Facts have proved that it is unintelligible that present embodiment has overcome the steel billet head imaging that causes owing to steel billet in the casting process is uneven in temperature, reduced the interference of external factor, reduced the manual intervention degree, improved continuous casting steel billet measurement of length precision.

Except that the foregoing description, the present invention can also have other embodiments.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection domain of requirement of the present invention.

Claims (4)

1. rectangular method is surveyed in a continuous casting steel billet shooting; In the length measurement system that constitutes by video camera and computing machine; The video line of camera lens and aperture controller is connected with the corresponding interface of computing machine through plug respectively with connection, in order to transmitting video data and communication information; The control output end of said aperture controller connects the controlled end of camera aperture motor; It is following to it is characterized in that surveying long step:

The first step, the foundation test obtains in computing machine steel billet head surface medial temperature and camera light number of turns mapping table;

Second step, computing machine are according to the slab thickness of importing, time step, molten steel coefficient of heat conductivity, molten steel density, molten steel thermal capacitance and initial steel billet central temperature, average surface temperature and intensity of cooling; By following formula, calculate steel billet head surface medial temperature in proper order:

$T_2^{p+1}=T_1^p+\frac{2\mathrm{\Δtk}\left(T_1^p\right)}{{\left(\mathrm{\Δx}\right)}^2\mathrm{\ρc}}(T_2^p-T_1^p)-\mathrm{\Δtq}/\left(\mathrm{\Δx\ρc}\right)$

In the following formula: P---the step-length number is natural number 1,2,3,4

T ₂ ^P+1---the billet surface medial temperature that time step P+1 is corresponding

T ₁ ^p---the steel billet central temperature that time step P is corresponding

T ₂ ^p---the billet surface medial temperature that time step P is corresponding

Δ t---time step

K---molten steel coefficient of heat conductivity

Δ x---space step-length

ρ---molten steel density

C---molten steel thermal capacitance

Q---intensity of cooling

The 3rd step, computing machine check in corresponding imaging aperture parameters according to the steel billet head surface medial temperature of calculating by said relation table, and are transferred to the aperture controller through connection, and then drive the aperture motor, regulate camera aperture;

The 4th step, computing machine are according to the camera shooting and video data of importing, and through Flame Image Process, identification continuous casting steel billet head position draws and surveys long result.

2. rectangular method is surveyed in shooting according to the said continuous casting steel billet of claim 1, it is characterized in that: said the 3rd step computing machine judges earlier whether steel billet head surface temperature value is higher than 1000 ℃ or be not lower than 700 ℃; When judgement is higher than 1000 ℃, output minimum aperture value; When judgement is lower than 700 ℃, the input lens speed.

3. continuous casting steel billet shooting measuring motion; Comprise the length measurement system that constitutes by video camera and computing machine; The video line of camera lens and aperture controller is connected with the corresponding interface of computing machine through plug respectively with connection, in order to transmitting video data and communication information; The control output end of said aperture controller connects the controlled end of camera aperture motor; It is characterized in that said computing machine also is used for:

Set up steel billet head surface medial temperature and camera light number of turns mapping table that test obtains;

According to slab thickness, time step, molten steel coefficient of heat conductivity, molten steel density, molten steel thermal capacitance and initial steel billet central temperature, average surface temperature and the intensity of cooling of input,, calculate steel billet head surface medial temperature in proper order by following formula:

$T_2^{p+1}=T_1^p+\frac{2\mathrm{\Δtk}\left(T_1^p\right)}{{\left(\mathrm{\Δx}\right)}^2\mathrm{\ρc}}(T_2^p-T_1^p)-\mathrm{\Δtq}/\left(\mathrm{\Δx\ρc}\right)$

In the following formula: P---the step-length number is natural number 1,2,3,4

T ₂ ^P+1---the billet surface medial temperature that time step P+1 is corresponding

T ₁ ^p---the steel billet central temperature that time step P is corresponding

T ₂ ^p---the billet surface medial temperature that time step P is corresponding

Δ t---time step

K---molten steel coefficient of heat conductivity

Δ x---space step-length

ρ---molten steel density

C---molten steel thermal capacitance

Q---intensity of cooling

According to the steel billet head surface medial temperature of calculating, check in corresponding imaging aperture parameters by said relation table, and be transferred to the aperture controller, and then drive the aperture motor through connection, regulate camera aperture;

According to the camera shooting and video data of input, through Flame Image Process, identification continuous casting steel billet head position draws and surveys long result.

4. according to the said continuous casting steel billet shooting of claim 3 measuring motion; It is characterized in that: said camera aperture controller is positioned at the front deck of camera; In order to input voltage is converted into the lens control circuit working voltage; And in order to receive the steering order of sending by system, be converted into the control voltage that drives each associated mechanisms of camera lens simultaneously, and accomplish aperture potentiometer value collection and be transformed to corresponding data output.

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