CN106771320B - A kind of rocket sledge image speed measurement method - Google Patents
A kind of rocket sledge image speed measurement method Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
- G01P3/36—Devices characterised by the use of optical means, e.g. using infrared, visible, or ultraviolet light
- G01P3/38—Devices characterised by the use of optical means, e.g. using infrared, visible, or ultraviolet light using photographic means
Abstract
A kind of rocket sledge image speed measurement method, the operational process of skid body is continuously shot using high speed camera, by the pitching and azimuth information amendment, the calculating of skid body feature point extraction, the speed of service to high speed camera relative orbit after the completion of test, the measurement to the skid body speed of service is completed.This method has rate accuracy height, thinking simple and clear, programs advantage easy to accomplish, improves the tachometric survey precision of key position in Rocket sled test.
Description
Technical field
The present invention relates to a kind of rocket sledge image speed measurement method more particularly to it is a kind of using high-speed camera be continuously shot come
The method for measuring the skid body speed of service, belongs to rocket sledge testing field.
Background technique
Rocket sled test has the ability for generating the integrated conditions such as big overload, high speed, strong vibration and impact, can most force
True simulation guided missile live flying environment.Items of inertial measurement system under the conditions of integrated environment can be examined by test
Energy index and precision verify correctness of the inertial measuring system error model under high dynamic condition, especially in big overload feelings
Under condition, high-order term amplification can determine influence of the inertial measurement system higher order error item to navigation performance, be to realize inertia
The optimal path of measuring system dynamic property verifying.
In inertial measurement system Rocket sled test, mainly filled at present using radar ranging devices, barn door time space measure
Set running position and the speed of measurement skid body.
Radar ranging devices are launched the electromagnetic wave of continuous constant amplitude and received from skid body from radar antenna to rocket sledge to be reflected
Electromagnetic wave signal back obtains the radial direction that skid body skid body is directed toward relative to antenna through processing using the Doppler frequency of measurement
The speed of service of speed and skid body along track.But there are following two disadvantages for radar velocity measurement:
(1) it is suitable for high speed to measure, low speed measurement accuracy is low.It is lower than in the practical application of Rocket sled test in speed
Not outputting measurement value when 10m/s；
(2) the wake flame effect of rocket sledge solid engines keeps the precision of radar surveying lower, in rocket sledge first class engine
With the data actual effect that can cause radar velocity measurement when second level engine ignition.
Barn door time space measure device is carried photoelectric subassembly by sledge and is installed along rocket sledge sliding rail side at interval of certain distance
Several barn doors composition.Photoelectric subassembly is mounted in skid body, is made of laser and laser pickoff, laser pickoff connection
There is processing circuit, realizes and cause the change transitions of luminous flux to be electric impulse signal barn door, and export to data collection system.
Data collection system then records the instantaneous moment of the electric pulse, can find out the fortune of skid body along the distance of track by adjacent barn door
Scanning frequency degree.But it is using the shortcomings that barn door photoelectric subassembly:
(1) laser of the photoelectric subassembly is more sensitive to the light after solid engines igniting, is easy to cause processing circuit
It is in a saturated state, so as to cause photoelectric subassembly operation irregularity；
(2) adjacent shading plate spacing is generally higher than 1 meter, seeks sledge divided by time of measuring interval using adjacent barn door distance
The method of the speed of running body haves the shortcomings that measurement error is relatively large.
As seen through the above analysis, 16km is extended to by 9km as rocket sledge track is subsequent, using multi-stage ignition
Demand is more more and more urgent, and radar velocity measurement and barn door time space measure have not adapted to the requirement of multi-stage ignition section.Therefore, it is necessary to grind
The new speed-measuring method of one kind is studied carefully to make up the defect of above two method.
In Rocket sled test field, existing high speed takes pictures at present, but is served only for observation engine ignition instantaneously multistage skid body point
Normally whether from, equal function monitorings purposes, the invention patent study a kind of realize on the basis of existing high speed takes pictures and test the speed
New method.
Summary of the invention
Technical problem solved by the present invention is having found a kind of rocket sledge image speed measurement method, this method can be accurate
Measure skid body operation speed, solve multi-stage engine separation when radar, barn door is influenced by engine ignition and what is failed asks
Topic, to provide high-precision velocity information.
The technical solution that the present invention solves is:
A kind of rocket sledge image speed measurement method, steps are as follows:
(1) in Rocket sled test, high speed camera is set up by the track at multi-stage engine separating ignition, and camera is set
Filming frequency f, in original photo longitudinal side length number of pixels M0With the number of pixels N of lateral side length0；It is opposite to measure camera
The distance between adjacent fastener L in the geography information and track of track；M0、N0It is positive integer, f, L are positive real number；
(2) during Rocket sled test multi-stage engine separating ignition, K width is continuously shot by high speed camera and is shone
Piece, K are positive integer；It is made of in every photos the mode of bidimensional pixel additional color, position of the pixel in photo
Information is the coordinate value of original photo pixel coordinate system；
(3) in each photos, the coordinate points (m, n) in original photo pixel coordinate system are transformed into original photo
Point (x, y) in center point coordinate system, conversion formula are as follows:
After converted, with (x, y, rx,y,gx,y,bx,y) position of the pixel and colouring information in original photo are described；
Right-handed coordinate system oxy of the original photo center point coordinate system using photo center as origin, ox axis horizontally to the right；
(4) photo is corrected according in the prefiring first photos middle orbit distortion information of multi-stage engine, so that photo
In space length corresponding to each pixel it is equal；
(5) distortionless photo after being corrected according to obtained in step (4), extracts rocket sledge skid body in each photos
Position (I of the fisrt feature point after amendment in photograph pixel point coordinate system om ' n 's,Js) and the fisrt feature point in this position
Pixel valueBehalf photo width number；
(6) the fisrt feature point horizontal direction pixel value J obtained according to step (5)sAnd the parameter in step (1), it asks
Take the velocity series of rocket sledge skid body；
(7) distortionless photo after being corrected according to obtained in step (4) extracts rocket sled skid body in each photos
Other feature point repeats step (5) and (6), obtains the velocity series of the corresponding rocket sledge skid body of each characteristic point, later with the
The corresponding velocity series of one characteristic point are merged, to obtain the overall process velocity series of rocket sledge skid body operation.
The origin of original photo pixel coordinate system omn is in the photo upper left corner, and downward, on axis is towards the right side for om axis；Pixel
Color value is made of red, green and blue difference ratio, with five dimension group (m, n, rm,n,gm,n,bm,n) indicate, wherein (m,
N) position of the pixel in photo is described, the value range of m is from 1 to M0Positive integer, the value range of n is from 1
To N0Positive integer；(rm,n,gm,n,bm,n) describe the colouring information of the pixel in original photo, red rm,n, green gm,n、
Blue bm,nValue range from 0 to 255.
The step (4) corrects photo according in the prefiring first photos middle orbit distortion information of multi-stage engine,
Specifically:
(3.1) it in the photo before correcting process, from left to right successively extracts the coordinate value of each fastener and is numbered,
Equipped with h >=4 fastener, with coordinate value (xp,yp) indicate, wherein p=1,2 ..., h；
(3.2) to the fastener sequence (x in photop,yp), p=1,2 ..., h；Using straight line model yl=klx+bl, with most
Small square law design factor klAnd blValue, specific formula for calculation is as follows:
Wherein,
(3.3) to the fastener sequence (x in photop,yp), p=1,2 ..., h；Calculate the distance l of two neighboring fastenerqWith
Center position coordinates (x0,q,y0,q), q=1,2 ..., h-1；Specific formula for calculation is
(3.4) the secondary distortion model of cut-off trajectoryUsing least square method design factor α and
β, specific formula is as follows:
Wherein
(3.5) according to factor alpha, klAnd blValue, be arranged M1And N1, and original photo is corrected, specific formula is as follows:
(rm',n',gm',n',bm',n')=(rm,n,gm,n,bm,n)
Wherein, array (rm,n,gm,n,bm,n) subscript m, n illustrates the coordinate point of original photo pixel coordinate system
It sets；Array (rm',n',gm',n',bm',n') subscript m ', n ' illustrate amendment after photograph pixel point coordinate system coordinate points position,
After correction photograph pixel point coordinate system om ' n ' be original photo correction after, using the photo upper left corner as origin, om ' axis vertically downward,
The coordinate system of on ' axis horizontally to the right；M1And N1The vertical and horizontal number of pixels of photo, enables m ' and n ' value after respectively correcting
Greater than 0；(x ', y ') indicates the coordinate points of optical center coordinate system ox ' y ' after correction, optical center coordinate system after correction
Ox ' y ' is after original photo is corrected, using photo center as origin, the right-handed coordinate system of ox ' axis horizontally to the right；
(3.6) in revised photo, there is the point not being colored, the photograph pixel after amendment in the region that is stretched
The region that is stretched is repaired in point coordinate system, specifically:
Wherein, (rm″,n″,gm″,n″,bm″,n″) indicating there is no the colouring information of upper color dot after correcting in photo, m " and n " is indicated
The coordinate position of the not upper color dot of photograph pixel point coordinate system after amendment, λ is indicated around the pixel in eight pixels, red
The sum of color, first pixel value of green, blue are greater than 0 number.
The fisrt feature point of rocket sledge skid body photograph pixel point after amendment in each photos of extraction in the step (5)
Position (I in coordinate system om ' n 's,Js) and the fisrt feature point this position pixel valueSpecifically
Are as follows:
(4.1) since the first photos, Z photos are chosen at equal intervals, find these photos photograph pixel after amendment
The skid body characteristic point coordinate (I of point coordinate system om ' n 's,Js)；Pixel value of the fisrt feature point in this position of skid body is extracted simultaneouslyWhereinRepresent coordinate points (Is,Js) red pixel value,Represent coordinate points (Is,Js) green picture
Element value,Represent coordinate points (Is,Js) blue pixel value, behalf picture width number；
The fisrt feature point for finding these photos at equal intervals, reads five dimension groups of these fisrt feature pointsRange where the above five dimensions group determines skid body fisrt feature point colorRed, green and blue domain value ranges are respectively (a1,a4),(a2,a5),(a3,a6), and sled
Body characteristics point coordinate (Is,Js) where range Imin≤Is≤Imax,Jmin≤Js≤Jmax；a1、a2、a3、a4、a5、a6It is positive whole
Number；
(4.2) since the first photos, each secondary photographic intelligence is read, according to Imin≤Is≤Imax,Jmin≤Js≤Jmax
Range internal coordinate point (Is,Js) color dataDetermine the position of characteristic point；IfMeet simultaneouslyWithAnd JsValue be most
When big, then (I is extracteds,Js), and record width number s；IfIt is not able to satisfyOrIn any one, then take Js=Js-1。
The step (6) is according to horizontal direction pixel value JsAnd the parameter in step (1), seek rocket sledge skid body
Velocity series, specific steps are as follows:
(5.1) x is given1(0) and x2(0) initial value 0；
(5.2) instantaneous velocity v in s pair photo is calculated according to the variation of characteristic point position in photos, 1≤s≤K -1, tool
Body formula are as follows:
vs=kfc (Js+1-Js)
C is the corresponding length of single pixel point in formula, and f is the frequency of camera shooting, Js+1And JsRespectively indicate s+1
The horizontal direction coordinate of prizing body characteristic point in photo and s photos, k are that proportionality coefficient k indicates that single pixel point corresponds in fact
The ratio of physical length on component, v are imaged with it for distance in the space of bordersFor instantaneous velocity；
(5.3) by the instantaneous velocity v of the characteristic point of all photossIt is arranged successively to form instantaneous velocity sequence sequentially in time
Column, obtain the velocity series of skid body after being smoothed to instantaneous velocity sequenceWherein, speed
Calculation formula be
Wherein, b0、A1、A2、B1、B2For the parameter of discretization second-order low-pass filter, x1(0) and x2It (0) is discretization two
Two initial parameters of rank low-pass filter.
The step (7) obtains the velocity series of the corresponding rocket sledge skid body of each characteristic point, later with fisrt feature point
Corresponding velocity series are merged, specifically:
(6.1) other characteristic points and fisrt feature point positional relationship, i.e. other characteristic point water are determined according to the first photos
Square to pixel value Js τWith the horizontal direction pixel value J of fisrt feature pointsBetween relationship:
Js τ=Js+ωτ
Wherein ωτIt is the difference of other characteristic points and fisrt feature point horizontal direction pixel value, τ=2,3,4 ..., Js τIt indicates
τ characteristic point horizontal direction pixel value；
(6.2) step (5) are repeated and obtains the velocity series of other characteristic points, it will other described characteristic point velocity series and the
One characteristic point velocity series in chronological sequence sequentially arrange, if synchronization there are multiple speed, takes these synchronization speed
Arithmetic average, thus complete fusion, obtain rocket sledge skid body operation overall process velocity series.
The present invention compared with prior art the advantages of it is as follows:
(1) the skid body speed of service when present invention can be accurately obtained rocket sledge multi-stage engine separating ignition, overcomes thunder
Up to the problem to test the speed, the measurement of barn door photoelectric subassembly is inaccurate, measurement accuracy is higher.
(2) this method can half fully automatic operation, do not need that excessive artificial participation is added, can be realized photo pitching
Skid body feature point extraction, the calculating of skid body speed and noise are eliminated before and after automatic amendment, engine ignition with azimuth deviation information,
Theoretical clear simple, programming is easy.
(3) method that still precise measurement can not be carried out to the skid body speed of service by high speed camera at present, this method
It is a kind of innovation, provides a kind for the treatment of method to analyze and evaluating the design rationality of Rocket sled test.
(4) photo is converted to numerical matrix by the present invention, is changed using numerical relation analysis characteristic point position, whole process
It is scientific and reasonable, rigorous accurate, while more rapidly can accurately read picture data and be analyzed.Photo eigen point is extracted simultaneously
Method, the data volume very little of required access can go out the photo that processing high-volume is continuously shot in very short time analysis
Characteristic point position variation
(5) all there is unsatisfactory place in amendment photo method used at present, need certain working environment, speed
Slowly, low efficiency and expensive.The present invention establishes the actual change that distortion model directly seeks the direction of motion to original photo, has
Its apparent advantage, greatly improves amendment efficiency.
(6) present invention method smooth using pie slice, the not only substantially influence of release rate noise, but also make
Rate curve more rationally, clearly, while being changed using multiple characteristic point analysis rocket sledge skid body speeds, is met and is hidden in environment
The requirement that the harshness external condition such as gear, light variation, multi-stage ignition can also accurately measure.
Detailed description of the invention
Fig. 1 is implementation flow chart of the present invention；
Fig. 2 is rocket sledge track and the fastener position in original photo.
Fig. 3 is fastener sequence straight line model；
Fig. 4 is secondary distortion model schematic diagram；
Fig. 5 is the photo after correction；
Fig. 6 is position of the skid body characteristic point I in photo；
Fig. 7 is position of the skid body characteristic point II in photo；
Fig. 8 is pixel position of the skid body characteristic point I in different photos；
Fig. 9 is pixel position of the skid body characteristic point II in different photos；
Figure 10 is the pixel position of skid body characteristic point I and characteristic point II after being aligned in different photos；
Figure 11 is fused rear pixel position of the skid body characteristic point I in different photos；
Figure 12 is the result of spectrum analysis to velocity noise；
Figure 13 is the calculated value and smooth value of the skid body speed of service.
Specific embodiment
Realization principle of the invention is: being continuously shot the operational process of skid body using high speed camera, leads to after the completion of test
It crosses and the pitching of high speed camera relative orbit and azimuth information amendment, skid body feature point extraction, the speed of service is calculated, complete to sledge
The measurement of running body speed.This method has rate accuracy height, thinking simple and clear, programs advantage easy to accomplish, improves
The tachometric survey precision of key position in Rocket sled test.
A kind of rocket sledge image speed measurement method is given below, it is characterised in that steps are as follows:
(1) high speed camera is set up by the track at Rocket sled test multi-stage engine separating ignition, the bat of camera is set
Take the photograph frequency f, in original photo longitudinal side length number of pixels M0With the number of pixels N of lateral side length0Etc. parameters；Measure camera phase
The distance between adjacent fastener L in geography information and track to track；M0、N0It is positive integer, f, L are positive real number；Such as Fig. 2
Shown, it is fastener in the position of rocket sledge track that label, which is the part of rectangular box, in the rocket sledge track of photo bottom,
Numerical value indicates the pixel distance of two adjacent fasteners in white box.
(2) during Rocket sled test multi-stage engine separating ignition, K width is continuously shot by high speed camera and is shone
Piece；It is made of in every photos the mode of bidimensional pixel additional color, location information of the pixel in photo is original
The coordinate value of photograph pixel point coordinate system；The origin of original photo pixel coordinate system (omn) in the upper left corner, om axis downward, on
Axis is towards the right side；The color value of pixel is made of red, green and blue difference ratio；With five dimension group (m, n, rm,n,gm,n,
bm,n) indicate, wherein (m, n) describes position of the pixel in photo, and the value range of m is from 1 to M0It is just whole
Number, the value range of n are from 1 to N0Positive integer；(rm,n,gm,n,bm,n) describe the color letter of the pixel in original photo
Breath, red rm,n, green gm,n, blue bm,nValue range from 0 to 255.
(3) in each photos, the coordinate points (m, n) in original photo pixel coordinate system are transformed into photo
The heart is origin, the point (x, y) in the right-handed coordinate system oxy (original photo center point coordinate system) of ox axis horizontally to the right, conversion
Formula is as follows:
After converted, with (x, y, rx,y,gx,y,bx,y) describe the position of the pixel and colouring information in original photo；
As shown in Figure 3 by original photo after discoloration is handled, indicia grid graduation mark, original photo center point coordinate system's horizontal axis and vertical
Axis is to intersect heavy black line in figure:
(4) photo is corrected according to the first photos middle orbit distortion information before engine ignition, so that every in photo
Space length corresponding to a pixel is equal；Correct the specific steps of photo are as follows:
A. it from left to right successively extracts the coordinate value of each fastener and is numbered, h (h >=4) a fastener is equipped with, with coordinate
It is worth (xp,yp) indicate, wherein p=1,2 ..., h；As shown in Fig. 2, label is rectangle side in the rocket sledge track of photo bottom
The part of frame is fastener in the position of rocket sledge track, it is marked one by one its coordinate value (xp, yp)；
B. to the fastener sequence (x in photop,yp), p=1,2 ..., h；Using straight line model yl=klx+bl,
With least square method design factor klAnd blValue, specific formula for calculation is as follows:
Wherein,
C. to the fastener sequence (x in photop,yp), p=1,2 ..., h；Calculate the distance l of two neighboring fastenerqThe center and
Position coordinates (x0,q,y0,q), q=1,2 ..., h-1；Specific formula for calculation is
D. the secondary distortion model of cut-off trajectoryUsing least square method design factor α and β, tool
Body formula is as follows:
Wherein
E. according to factor alpha, klAnd blValue, be arranged M1And N1, and correction original photo,
Specific formula is as follows:
(rm',n',gm',n',bm',n')=(rm,n,gm,n,bm,n)
Wherein array (rm,n,gm,n,bm,n), subscript m, n illustrates the coordinate points position of original photo pixel coordinate system；
Array (rm',n',gm',n',bm',n'), subscript m ', n ' illustrates the coordinate points position of photograph pixel point coordinate system after correction, correction
Afterwards photograph pixel point coordinate system (om ' n ') be original photo correction after, using the photo upper left corner as origin, om ' axis vertically downward,
The coordinate system of on ' axis horizontally to the right；M1And N1The vertical and horizontal number of pixels of photo, value should be guaranteed that after respectively correcting
M ' and n ' is greater than 0；(x ', y ') illustrates the coordinate points of optical center coordinate system (ox ' y ') after correction, photo center after correction
Point coordinate system (ox ' y ') is after original photo is corrected, using photo center as origin, the right-handed coordinate system of ox ' axis horizontally to the right.
F. there is the point not being colored in the region being stretched, after correcting in photograph pixel point coordinate system after correction
Photo method for repairing and mending are as follows:
Wherein, (rm″,n″,gm″,n″,bm″,n″) indicating there is no the colouring information of upper color dot after correcting in photo, m " and n " is indicated
The coordinate position of the not upper color dot of photograph pixel point coordinate system after amendment, λ is indicated around the pixel in eight pixels, red
The sum of color, first pixel value of green, blue are greater than 0 number.Pass through revised photo as shown in Figure 5, wherein each pixel
Space actual range representated by point size is equal, and the repair part of photo is the outside black portions of photo；
(5) distortionless photo after being corrected according to obtained in step (4), extracts rocket sledge skid body in each photos
Position (I of the fisrt feature point after amendment in photograph pixel point coordinate system om ' n 's,Js) and the fisrt feature point in this position
Pixel valueBehalf photo width number；As shown in fig. 6, fisrt feature point is in the black middle line portion of rocket sledge
Divide right end；
(6) parameter in horizontal direction pixel value and step (1) obtained according to step (5), seeks the instantaneous of skid body
Speed, specific steps are as follows:
A. x is given1(0) and x2(0) initial value 0；
B. instantaneous velocity v in s pair photo is calculated according to the variation of characteristic point position in photos, 1≤s≤K -1, specifically
Formula are as follows:
vs=kfc (Js+1-Js)
C is the corresponding length of single pixel point in formula, and f is the frequency of camera shooting, Js+1And JsRespectively indicate s+1
The horizontal direction coordinate of prizing body characteristic point in photo and s photos, k are that proportionality coefficient k indicates that single pixel point corresponds in fact
The ratio of physical length on component, v are imaged with it for distance in the space of bordersFor instantaneous velocity；
C. by the instantaneous velocity v of the characteristic point of all photossIt is arranged successively to form instantaneous velocity sequence sequentially in time,
The velocity series of skid body are obtained after being smoothed to instantaneous velocity sequenceWherein, speed's
Calculation formula is
Wherein, b0、A1、A2、B1、B2For the parameter of discretization second-order low-pass filter, x1(0) and x2It (0) is discretization two
Two initial parameters of rank low-pass filter.If Figure 12 is the result of spectrum analysis to velocity noise, it can be seen that noise is main
Frequency range is the high band greater than 10Hz；Therefore, second-order low-pass filter is used to be filtered to eliminate high-frequency noise speed
(7) distortionless photo after being corrected according to obtained in step (4), extracts other spies of skid body in each photos
Point is levied, repeats step (5) and (6), is merged after obtaining speed with the speed obtained using characteristic point I, to obtain skid body
The overall process velocity series of operation.Such as the calculated value and smooth value that Figure 13 is the skid body speed of service, while the clear earth's surface of smooth value
The overall process movement velocity of bright rocket sledge changes.
The implementation method of characteristic point is extracted in the step (5):
(1) since the first photos, Z photos are chosen at equal intervals, find these photos photograph pixel point after correction
The skid body characteristic point coordinate (I of coordinate system (om ' n ')s,Js)；Pixel value of the characteristic point in this position of skid body is extracted simultaneouslyWhereinRepresent coordinate points (Is,Js) red pixel value,Represent coordinate points (Is,Js) green picture
Element value,Represent coordinate points (Is,Js) blue pixel value, behalf picture width number.According to these, photo determines prizing body at equal intervals
Characteristic point colorDomain value range is respectively (a1,a4),(a2,a5),(a3,a6) and prizing body characteristic point
Coordinate (Is,Js) where range Imin≤Is≤Imax,Jmin≤Js≤Jmax。
(2) since the first photos, each secondary photographic intelligence is read, according to Imin≤Is≤Imax,Jmin≤Js≤JmaxModel
Enclose internal coordinate point (Is,Js) color dataDetermine the position of characteristic point；If
Meet simultaneously And JsValue when being maximum, then extract (Is,Js),
And record width number s；IfIt is not able to satisfy
Any one, then take Js=Js-1.If Fig. 8 is characterized pixel position of the point I in each photos, wherein pixel position is
It is taken out with the coordinate in photograph pixel point coordinate system after correction, has rough part mainly due to ambient noise and light in curve
Line influences, and takes Js=Js-1, but have no effect on curve general trend and precision；After being fused such as Figure 11, skid body characteristic point exists
Pixel position in each photos, wherein pixel position is taken out with the coordinate after correction in photograph pixel point coordinate system,
After characteristic point II is by translation, by the characteristic point II pixel position and characteristic point I pixel position in chronological sequence sequence
Arrangement, if synchronization there are multiple pixel positions, takes the arithmetic average of these synchronization pixel positions.
The measurement of the rocket sledge skid body speed of service can be completed by the above method.
Embodiment:
In a Rocket sled test, if filming frequency f=2000 width/second, the corresponding length c=22 μ of single pixel point
M, proportionality coefficient k is=853.65.Fig. 2 is the position of rocket sledge track and fastener in original photo, and by image
Photo processing is no ambient noise by reason, and it is fastener that label, which is the part of rectangular box, in the rocket sledge track of photo bottom
In the position of rocket sledge track, numerical value indicates the pixel distance of two adjacent fasteners in white box.；Fig. 3 is fastener sequence
Vertical straight line model is set up in the point of original photo, coordinate system is using photo center as origin, the right hand of ox axis horizontally to the right
Coordinate system oxy (original photo center point coordinate system), reference axis is indicated with photo intermediate interdigitated heavy black line, and the straight line of foundation is
Y=-0.01057x-101.2；Fig. 4 is that secondary distortion model schematic diagram indicates pixel position and adjacent fastener apart from derivative
Relationship, what empty circles represented in figure is relationship of the known adjacent fastener apart from derivative and pixel position, and black curve is
According to the matched curve that empty circles position is formed, the distortion model of foundation isFig. 5 is correction
Photo afterwards wherein space actual range corresponding to each pixel is equal, and has been repaired in the region being stretched and has been existed
The part for the point not being colored；Fig. 6 is characterized position of the point I in skid body, this characteristic point is intermediate black in rocket sledge skid body
The right end of color linear parts has very big difference with surrounding pixel point color value, is easy to determine that range takes out its coordinate, meets
The operation requirement of characteristic point is read, still, characteristic point I can be blocked in Fig. 7 photo, therefore, and selected characteristic point II, this feature
Point is black triangles tapered top portion shell white centers point in rocket sledge skid body, and Fig. 7 is seen in the position in skid body；Fig. 8 is spy
Pixel position of the point I in each photos is levied, wherein pixel position is with the seat after correction in photograph pixel point coordinate system
Mark takes out, and has rough part mainly due to ambient noise and light influence in curve, but has no effect on curve and totally become
Gesture and precision, Fig. 9 are characterized pixel position of the point II in each photos, and wherein pixel position is with photo picture after correction
Coordinate in vegetarian refreshments coordinate system takes out, and can carry out after passing through translation from the position of the 70th width to the 140th width and characteristic point I
Compare verifying；Figure 10 is the pixel position to characteristic point I and characteristic point II pixel position after being aligned in each photos；
After being fused such as Figure 11, pixel position of the skid body characteristic point in each photos, after wherein pixel position is to correct
Coordinate in photograph pixel point coordinate system takes out, after characteristic point II is by translation, by the characteristic point II pixel position and spy
Sign point I pixel position in chronological sequence sequentially arranges, if synchronization takes these synchronizations there are multiple pixel positions
The arithmetic average of pixel position；Figure 12 is to the result of spectrum analysis of velocity noise, it can be seen that the main frequency range of noise is
High band greater than 10Hz；Therefore, second-order low-pass filter is used to be filtered speed to eliminate high-frequency noise, Figure 13 is sledge
The calculated value and smooth value of running body speed, it can be seen that calculated value has the fluctuation of constant amplitude, keeps stable tendency, while smooth value
It clearly shows that the movement velocity variation tendency of rocket sledge, so far completes rocket sledge image speed measurement overall process.
The present invention is not described in detail content and is known to the skilled person technology.
Claims (6)
1. a kind of rocket sledge image speed measurement method, it is characterised in that steps are as follows:
(1) in Rocket sled test, high speed camera is set up by the track at multi-stage engine separating ignition, the bat of camera is set
Take the photograph frequency f, in original photo longitudinal side length number of pixels M0With the number of pixels N of lateral side length0；Measure camera relative orbit
Geography information and track on the distance between adjacent fastener L；M0、N0It is positive integer, f, L are positive real number；
(2) during Rocket sled test multi-stage engine separating ignition, K photos are continuously shot by high speed camera, K is
Positive integer；It is made of in every photos the mode of bidimensional pixel additional color, location information of the pixel in photo is
The coordinate value of original photo pixel coordinate system；
(3) in each photos, the coordinate points (m, n) in original photo pixel coordinate system are transformed into original photo center
Point (x, y) in point coordinate system, conversion formula are as follows:
After converted, with (x, y, rx,y,gx,y,bx,y) position of the pixel and colouring information in original photo are described；
Right-handed coordinate system oxy of the original photo center point coordinate system using photo center as origin, ox axis horizontally to the right；
(4) photo is corrected according in the prefiring first photos middle orbit distortion information of multi-stage engine, so that every in photo
Space length corresponding to a pixel is equal；
(5) distortionless photo after being corrected according to obtained in step (4), extracts first of rocket sledge skid body in each photos
Position (I of the characteristic point after amendment in photograph pixel point coordinate system om ' n 's,Js) and the fisrt feature point this position pixel
ValueBehalf photo width number；
(6) the fisrt feature point horizontal direction pixel value J obtained according to step (5)sAnd the parameter in step (1), seek fire
The velocity series of arrow sledge skid body；
(7) distortionless photo after being corrected according to obtained in step (4) extracts rocket in each photos and prizes the other of skid body
Characteristic point repeats step (5) and (6), obtains the velocity series of the corresponding rocket sledge skid body of each characteristic point, special with first later
The corresponding velocity series of sign point are merged, to obtain the overall process velocity series of rocket sledge skid body operation.
2. a kind of rocket sledge image speed measurement method according to claim 1, it is characterised in that: original photo pixel coordinate
Be omn origin in the photo upper left corner, downward, on axis is towards the right side for om axis；The color value of pixel is by red, green and blue are different
Ratio is constituted, with five dimension group (m, n, rm,n,gm,n,bm,n) indicate, wherein (m, n) describes position of the pixel in photo
It sets, the value range of m is from 1 to M0Positive integer, the value range of n is from 1 to N0Positive integer；(rm,n,gm,n,bm,n) description
The colouring information of the pixel, red r in original photom,n, green gm,n, blue bm,nValue range from 0 to 255.
3. a kind of rocket sledge image speed measurement method according to claim 1, it is characterised in that: step (4) basis exists
The prefiring first photos middle orbit distortion information of multi-stage engine corrects photo, specifically:
(3.1) it in the photo before correcting process, from left to right successively extracts the coordinate value of each fastener and is numbered, be equipped with
H >=4 fastener, with coordinate value (xp,yp) indicate, wherein p=1,2 ..., h；
(3.2) to the fastener sequence (x in photop,yp), p=1,2 ..., h；Using straight line model yl=klxl+bl, with minimum two
Multiplication design factor klAnd blValue, specific formula for calculation is as follows:
Wherein,
(3.3) to the fastener sequence (x in photop,yp), p=1,2 ..., h；Calculate the distance l of two neighboring fastenerqThe center and
Position coordinates (x0,q,y0,q), q=1,2 ..., h-1；Specific formula for calculation is
(3.4) the secondary distortion model of cut-off trajectoryUsing least square method design factor α and β, tool
Body formula is as follows:
Wherein
(3.5) according to factor alpha, klAnd blValue, be arranged M1And N1, and original photo is corrected, specific formula is as follows:
(rm',n',gm',n',bm',n')=(rm,n,gm,n,bm,n)
Wherein, array (rm,n,gm,n,bm,n) subscript m, n illustrates the coordinate points position of original photo pixel coordinate system；Number
Group (rm',n',gm',n',bm',n') subscript m ', n ' illustrate amendment after photograph pixel point coordinate system coordinate points position, after correction
Photograph pixel point coordinate system om ' n ' be original photo correction after, using the photo upper left corner as origin, om ' axis vertically downward, on ' axis
Coordinate system horizontally to the right；M1And N1The vertical and horizontal number of pixels of photo after respectively correcting enables m ' and n ' value be greater than 0；
(x ', y ') indicates the coordinate points of optical center coordinate system ox ' y ' after correction, and optical center coordinate system ox ' y ' is after correction
After original photo correction, using photo center as origin, the right-handed coordinate system of ox ' axis horizontally to the right；
(3.6) in revised photo, there is the point not being colored in the region that is stretched, photograph pixel point is sat after amendment
The region that is stretched is repaired in mark system, specifically:
Wherein, (rm″,n″,gm″,n″,bm″,n″) indicating there is no the colouring information of upper color dot after correcting in photo, m " and n " indicates repairing
The coordinate position of the not upper color dot of photograph pixel point coordinate system, λ are indicated around the pixel in eight pixels after just, red,
The sum of first pixel value of green, blue is greater than 0 number.
4. a kind of rocket sledge image speed measurement method according to claim 1, it is characterised in that:
The fisrt feature point of rocket sledge skid body photograph pixel point coordinate after amendment in each photos of extraction in the step (5)
It is the position (I in om ' n 's,Js) and the fisrt feature point this position pixel valueSpecifically:
(4.1) since the first photos, Z photos are chosen at equal intervals, are found these photos photograph pixel point after amendment and are sat
The skid body characteristic point coordinate (I of mark system om ' n 's,Js)；Pixel value of the fisrt feature point in this position of skid body is extracted simultaneouslyWhereinRepresent coordinate points (Is,Js) red pixel value,Represent coordinate points (Is,Js) green picture
Element value,Represent coordinate points (Is,Js) blue pixel value, behalf picture width number；
The fisrt feature point for finding these photos at equal intervals, reads five dimension groups of these fisrt feature pointsRange where the above five dimensions group determines skid body fisrt feature point colorRed, green and blue domain value ranges are respectively (a1,a4),(a2,a5),(a3,a6), and sled
Body characteristics point coordinate (Is,Js) where range Imin≤Is≤Imax,Jmin≤Js≤Jmax；a1、a2、a3、a4、a5、a6It is positive whole
Number；
(4.2) since the first photos, each secondary photographic intelligence is read, according to Imin≤Is≤Imax,Jmin≤Js≤JmaxRange
Internal coordinate point (Is,Js) color dataDetermine the position of characteristic point；IfTogether
When meetWithAnd JsValue when being maximum, then extract (Is,Js),
And record width number s；IfIt is not able to satisfyOrIn any one, then take Js=Js-1。
5. a kind of rocket sledge image speed measurement method according to claim 1, it is characterised in that: the step (6) is according to water
Square to pixel value JsAnd the parameter in step (1), seek the velocity series of rocket sledge skid body, specific steps are as follows:
(5.1) x is given1(0) and x2(0) initial value 0；
(5.2) instantaneous velocity v in s pair photo is calculated according to the variation of characteristic point position in photos, 1≤s≤K -1, specific public affairs
Formula are as follows:
vs=kfc (Js+1-Js)
C is the corresponding length of single pixel point in formula, and f is the frequency of camera shooting, Js+1And JsRespectively indicate s+1 photos and
The horizontal direction coordinate of prizing body characteristic point in s photos, k are that proportionality coefficient k indicates that single pixel point corresponds to real space
In distance the ratio of physical length on component, v are imaged with itsFor instantaneous velocity；
(5.3) by the instantaneous velocity v of the characteristic point of all photossIt is arranged successively to form instantaneous velocity sequence sequentially in time, it is right
Instantaneous velocity sequence obtains the velocity series of skid body after being smoothedWherein, speedCalculating
Formula is
Wherein, b0、A1、A2、B1、B2For the parameter of discretization second-order low-pass filter, x1(0) and x2It (0) is discretization step low-pass
Two initial parameters of filter.
6. a kind of rocket sledge image speed measurement method according to claim 1, it is characterised in that: the step (7) obtains often
The velocity series of the corresponding rocket sledge skid body of a characteristic point, velocity series corresponding with fisrt feature point are merged later, tool
Body are as follows:
(6.1) other characteristic points and fisrt feature point positional relationship, i.e. other characteristic point level sides are determined according to the first photos
To pixel value Js τWith the horizontal direction pixel value J of fisrt feature pointsBetween relationship:
Js τ=Js+ωτ
Wherein ωτIt is the difference of other characteristic points and fisrt feature point horizontal direction pixel value, τ=2,3,4 ..., Js τIndicate τ
Characteristic point horizontal direction pixel value；
(6.2) step (5) are repeated and obtains the velocity series of other characteristic points, it will other described characteristic point velocity series and the first spy
Sign spot speed degree series in chronological sequence sequentially arrange, if synchronization there are multiple speed, takes the calculation of these synchronization speed
Number average value, thus completes fusion, obtains the overall process velocity series of rocket sledge skid body operation.
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