CN106778823A - A kind of readings of pointer type meters automatic identifying method - Google Patents
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Abstract
A kind of readings of pointer type meters automatic identifying method proposed by the present invention, belongs to digital image processing field.The method is comprised the following steps：Gather and gauged instrument template, instrument minimax range, unit in Prototype drawing, Prototype drawing, and template gauge pointer current location reading are stored in ATL；Maximum, minimum scale line, the pointer straight line of instrument in Prototype drawing are searched, the home position of the angle of minimax graduation mark, instrument is stored in ATL；Template matches, positive visual angle figure is corrected to by meter diagram to be identified；Using pointer lookup method, the pointer straight line in meter diagram to be identified is searched, calculate meter reading.The method that the method is demarcated using template, the foundation of early stage ATL is simple, and need to only search a minimax graduation mark angle, determine home position and be stored in ATL, later stage need to only recognize the angle of the pointer of each instrument to be identified, reduce the information content of computer identification, and reliability is high.
Description
Technical field
The invention belongs to digital image processing field, specifically a kind of readings of pointer type meters automatic identifying method.
Background technology
Pointer instrument is widely used in the industries such as electric power, oil, and traditional artificial reading efficiency is low, and workload is big, receives
People's subjective factor influences, and in some environments, such as by installation site height factor, it is difficult to carry out artificial reading.Will figure
The automatic identification of meter reading is applied to as treatment technology, efficiency can be improved, mitigate person works' amount, guaranteed personal safety.
The existing readings of pointer type meters automatic identifying method based on image processing techniques is related generally to graduation mark
Search, pointer is searched, scale numeral is recognized, center of circle positioning.Because actual picture is influenceed by factors such as the dirts on light, dial plate
And it is smudgy, cause the information such as tiny graduation mark, numeral recognize less than, cause meter reading automatic identification fail.For
The center of circle positioning of instrument dial, existing by searching meter dial line, fitting circle determines the center of circle, but instrument pictorial information
Amount is big, more difficult in actual picture to determine meter dial line, the especially lookup of tiny graduation mark.
Existing patent CN101620682A, patent name is a kind of readings of pointer type meters method, the side that the patent is used
Method is：The scale inquiry table of different instrument is set up, database is formed；Acquisition instrument image, is input into Instrument image and it is carried out
Pretreatment, to extract effective identification region of instrument dial plate；From effective identification region of instrument dial plate, using pointer and scale
Line stroke feature, extracts the pointer and graduation mark of instrument；According to the pointer and graduation mark that extract, the graduation mark and scale that will be extracted
Corresponding scale inquiry table is matched in lookup table database, carries out reading automatic identification.The data that the method early stage is set up
Storehouse is cumbersome, and workload is very big.
Known technology of the present invention includes：
1) template picture is given, the Instrument image collected during to scene application carries out Slant Rectify, obtains instrument
The front view of table image, to improve the precision of total indicator reading identification, the matching of image key points is realized using existing SIFT algorithms,
And the key point obtained by matching, perspective transformation matrix is tried to achieve, then pair picture similar to Prototype drawing carries out Slant Rectify.
2) the ID numbering identification technologies of instrument.When needing to carry out polylith instrument the identification of reading automated graphics, Jun Xushi
Which block instrument other Instrument image is belonging to.Two-dimension code label can be sticked to every piece of instrument in advance, so the either mould of instrument
Include image in 2 D code in the meter diagram for treating reading of plate figure and collection in worksite, using ripe Quick Response Code identification software
Recognize the Quick Response Code in the image, you can obtain the ID numberings of instrument.
The content of the invention
It is not enough that the purpose of the present invention is directed to prior art, there is provided a kind of readings of pointer type meters automatic identifying method, this
Inventive method can reduce the required information content of computer identification, improve the success rate and accuracy rate of meter reading automatic identification, and
The foundation of early stage ATL is simple.
A kind of readings of pointer type meters automatic identifying method proposed by the present invention, comprises the following steps：
1) collection and gauged instrument Prototype drawing, the instrument Prototype drawing is the positive visual angle figure shot to instrument, by instrument template
Meter reading in instrument minimax range, unit, and instrument Prototype drawing, is stored in ATL in figure, instrument Prototype drawing；
2) maximum, minimum range graduation mark, the pointer straight line of instrument in Prototype drawing are searched, home position is determined, and will most
The angle of big minimum range graduation mark, the home position of instrument dial are stored in ATL；
3) the instrument Prototype drawing in meter diagram to be identified and ATL is carried out into crucial Point matching, obtains perspective transformation matrix
Afterwards, meter diagram to be identified is corrected to positive visual angle figure；
4) using the pointer lookup method of auto-adaptive parameter, the pointer straight line in meter diagram to be identified is searched, calculates instrument
Reading.
The step 2) in minimax range scale line lookup method and home position determination, according to following condition
Judge, 1. minimax range scale line, the relative angular difference of pointer straight line and the proportional relation of relative difference of reading；2. maximum is most
Small-range graduation mark, pointer straight line intersection are in the center of circle；3. the lookup method of straight line is using with auto-adaptive parameter lookup method.
(for the determination of the lookup method and home position of the minimax range scale line of instrument in Prototype drawing, know in whole image
Need to only be carried out once in other method, and by recognition result such as instrument dial home position and the angle of minimax range scale line
Degree is stored in ATL, and the information in ATL need to be only called in the meter reading identification process in later stage.)
In every Prototype drawing the lookup of minimax range scale line and the determination of home position of instrument specifically include with
Lower step：
21) according to the Slope relationship of instrument minimax range scale straight line, find out and meet in instrument Prototype drawing slope pass
The straight line pair of system, has n pairs；
22) according to the angle of every a pair of straight lines, and in Prototype drawing, instrument is read in minimax range, the Prototype drawing of instrument
Number, if it is minimax range scale line to calculate i-th pair straight line, the angle of template pointer is θ i, and i-th pair straight line intersection point
Coordinate (xi,yi), i=0,1 ... n；
23) angle is θ i in searching instrument Prototype drawing, and by coordinate (xi,yi) straight line, if in the presence of such straight
Line, then i-th pair straight line be minimax range scale line, the center of circle is (xi,yi), and by the angle of maximum range graduation mark
θmax, minimum range graduation mark angle, θminAnd central coordinate of circle (xi,yi) be stored in ATL.
The step 4) in auto-adaptive parameter pointer lookup method, search the pointer straight line in meter diagram to be identified, meter
Meter reading is calculated, is specifically included：During identification meter reading, carved according to existing template picture maximum, minimum range in ATL
The angle of line is spent, maximum, minimum range, lookup has been corrected to the pointer in the instrument picture of front view, and calculates its angle, i.e.,
Try to achieve meter reading (information content of required identification is small) as follows：
In formula, θ is the angle of gauge pointer in figure to be identified, θmaxIt is the angle of maximum range graduation mark, θminIt is minimum
The angle of range scale line, SmaxIt is maximum range reading, SminIt is minimum range reading, S is instrument in meter diagram to be identified
Reading.
The angle, θ of maximum range graduation markmax, minimum range graduation mark angle, θmin, maximum range Smax, minimum range
SminThe parameter that the instrument has been stored in ATL is, can be obtained in ATL, only need to recognize gauge pointer straight line simultaneously
Calculate its angle, θ, you can try to achieve meter reading.
The step 2) and step 4) in auto-adaptive parameter pointer lookup method in, specifically include：In image space
Linear equation y=kx+b, is expressed as with polar form：R=xcos β+ysin β.A is turned to by parameter space is discrete
(ri,βi) accumulator element, to pixel (x in imagei, yi), carry out Hough transform, βiTraversal [0, π) in centrifugal pump calculate
Obtain ri, then A (ri,βi) value of accumulator element that represents adds 1；Specific steps include：
(1) point (x in random selection set of characteristic pointsi, yi), if not detecting the point also, the point is carried out
Hough transform；
(2) if there is a certain accumulator A (ri,βi) value be more than or equal to threshold value N1, then correspondence parameter r is exportediAnd βi,
Then accumulator A (r are emptiedi,βi)；
(3) according to the straight line parameter for obtaining, the corresponding straight line l in original image of the point is found outk, and the straight line will be belonged to
Characteristic point all mark for detection；
(4) straight line lkLength Lk, threshold value L1If, Lk≥L1, illustrate that the straight line for detecting meets accumulator parameter, length ginseng
Number threshold value, then record straight line lkIn set M；
(5) if also there is the point for not yet detecting in point set, return to step (1) continues to detect；
(6) pointer straight line is selected in the straight line set M for being detected from step (4), the angle or the center of circle according to straight line are arrived
The distance of straight line, finds out the pointer straight line in set M；If there is no pointer straight line, then change the accumulator threshold of Hough transform
Value parameter or straight length threshold parameter, empty straight line set M；
(7) if accumulator threshold parameter N1, straight length threshold parameter L1In the case of do not find out pointer straight line, as long as tired
Plus device threshold parameter N1Not less than the lower limit N of threshold value2, change accumulator threshold value N1=N1-N0, repeat step (1)-(6), directly
To pointer straight line is found, terminate iteration.Wherein N0It is accumulator threshold steps；If accumulator threshold value N1Less than the lower limit of threshold value
N2, still do not find pointer straight line, then change straight length threshold parameter；If straight length threshold value L1Not less than under threshold value
Limit value L2, change accumulator threshold parameter, L1=L1-L0, repeat step (1)-(6), until finding pointer straight line, terminate to change
Generation, wherein L0It is straight length threshold steps.
Compared with prior art, advantages of the present invention：
(1) using the pointer straight line lookup method of auto-adaptive parameter.Accumulator threshold value, straight length threshold in Hough transform
Value is two important parameters of pointer line judgment.Because every pictures feature is different, different pictures needs to set different
Parameter, can just find out pointer straight line.Auto-adaptive parameter algorithm, can be according to the actual conditions per pictures, adjust automatically accumulator
Threshold value, two important parameter values of straight length threshold value, until finding pointer straight line.
(2) ATL, including template picture, minimax range, the current reading of instrument, unit are set up.Determine Prototype drawing
The home position of piece instrument, the angle of minimax graduation mark are simultaneously stored in ATL, and the process recognizes journey in whole image
Need to only be carried out once in sequence, the information in ATL need to be only called during the Meter recognition in later stage, and the foundation of ATL is simple
It is single.
(3) method demarcated using template, it is maximum when the meter diagram to be identified to being corrected to front view carries out Recognition of Reading
The angle of range scale line, the angle of minimum range graduation mark, maximum range, minimum range be able to can be obtained in ATL
Arrive, it is only necessary to search gauge pointer straight line and angle, it is not necessary to recognize the information such as tiny graduation mark, numeral in picture, significantly
The information content of computer identification is reduced, reliability is improved.
Brief description of the drawings
Fig. 1 is a kind of readings of pointer type meters automatic identifying method flow chart proposed by the present invention.
Specific embodiment
A kind of readings of pointer type meters automatic identifying method proposed by the present invention, with reference to the accompanying drawings and detailed description
The present invention is further elaborated.
A kind of readings of pointer type meters automatic identifying method proposed by the present invention, flow chart is as shown in figure 1, including following step
Suddenly：
Step 1：Its instrument Prototype drawing is gathered and demarcated for each instrument, and the instrument Prototype drawing is that instrument is shot
Positive visual angle figure, meter reading in instrument Prototype drawing, the minimax range of instrument, unit, and instrument Prototype drawing is preserved
In ATL；
Step 2：Minimax range scale line, the pointer straight line of instrument in Prototype drawing are searched, dial center of circle position is determined
Put, and the angle of minimax range scale line, instrument dial home position are stored in ATL；
The determination of the lookup method and home position of minimax range scale line, according to following condition judgment：1. maximum
Minimum range graduation mark, the relative angular difference of pointer straight line and the proportional relation of relative difference of reading；2. minimax range scale
Line, pointer straight line intersection are in the dial center of circle；3. the lookup method of straight line is using the self adaptation lookup method with robustness；
For the lookup and the determination of home position of the minimax range scale line of instrument in Prototype drawing, in whole image
Need to only be carried out once in recognizer, the information in ATL need to be only called during the Meter recognition in later stage, i.e., from ATL
In obtain the angle of instrument home position and minimax range scale line.The minimax range of instrument is carved in every Prototype drawing
The lookup of line and the determination of home position are spent, following steps are specifically included：
21) according to the Slope relationship of instrument minimax range scale straight line, to find out and meet Slope relationship in Prototype drawing
Straight line is to (one group maximum, minimum straight line turn into straight line to)；
The corresponding differential seat angle of slope according to minimax scale straight line is α0, during actual lookup graduation mark, differential seat angle model
It is [α to enclose0-20,α0+ 20], two straight lines of following relationship are met in lookup Prototype drawing：
Two extreme coordinates of straight line are (x in formula1,y1), (x2,y2), the two of straight line extreme coordinates in addition
It is (x3,y3), (x4,y4).Assuming that searching qualified straight line to having n pairs according to the constraint of formula (1)；
22) according to the angle of every a pair of straight lines, and meter reading is sentenced in minimax range, Prototype drawing in Prototype drawing
Disconnected, if i-th pair straight line is minimax range scale line, the angle of template pointer is θ0i, in the present embodiment, the definition of angle with
The center of circle is origin, is 0 ° with the downward longitudinal axis, clockwise for just, angular range is [0 °, 360 °]；The angle, θ of calculation template pointer0i
It is formula (2)：
Wherein, SmaxIt is maximum range, SminIt is minimum range, S0It is gauge pointer reading in the Prototype drawing, from ATL
In obtain；θ1iIt is angle, the θ of minimum range graduation mark in i-th pair graduation mark2iIt is maximum range graduation mark in i-th pair graduation mark
Angle；
The intersecting point coordinate for calculating i-th pair straight line according to formula (2) is (xi,yi), i=0,1 ... n；
23) angle is θ in searching instrument template picture0i, and by coordinate (xi,yi) straight line, if in the presence of such
Straight line, then i-th pair straight line be minimax range scale line, in Prototype drawing the instrument center of circle be (xi,yi), and by maximum range
The angle, θ of graduation markmax, minimum range graduation mark angle, θminAnd central coordinate of circle (xi,yi) be stored in ATL；
Angle is θ during the present embodiment searches instrument template picture0i, and by coordinate (xi,yi) straight line self adaptation
Parametric method look for：
Linear equation y=kx+b in image space, (wherein k is slope and b is y intercept) uses polar form table
It is shown as：R=xcos β+ysin β r >=0,0≤β ＜ π；
The coordinate (x, y) at rectangular coordinate system midpoint, the two of the coordinate position of point parameters are r in correspondence polar coordinate system
With β, r represents length a little to the origin of coordinates, referred to as polar diameter, and β is referred to as the polar angle of this point, i.e., relative to the angle of 0 degree of level
Degree；
In order to find the straightway of these point compositions, many accumulator element A are parameterized into by two of polar coordinate position
(ri,βi).To image midpoint (xi, yi), carry out Hough transform, βiTraversal [0, π) in centrifugal pump be calculated ri, then A
(ri,βi) value of accumulator element that represents adds 1；
According to the actual conditions per pictures, adjust automatically accumulator threshold value, straight length threshold value two in the present embodiment
Important parameter value, until finding minimax scale straight line；Concretely comprise the following steps：
231) point (x in random selection set of characteristic pointsi, yi), if not detecting the point also, the point is carried out
Hough transform；
232) if there is a certain accumulator A (ri,βi) value be more than or equal to accumulator threshold value N1, (initial value can be taken as mesh
50%) that marks straight length pixel value then exports line correspondence parameter riAnd βi, then empty accumulator A (ri,βi)；
233) according to the straight line parameter r for obtainingiAnd βi, found out the corresponding straight line l in original image of the pointk, and will category
It is detection all to be marked in the characteristic point (being determined by known technology) of the straight line；
234) straight line lkLength Lk, length parameter threshold value L1(initial value can be taken as the pixel value of target line length
50%), if Lk≥L1, illustrate that the straight line for detecting meets accumulator parameter, length parameter threshold value L1, then straight line l is recordedk
In set of characteristic points M；
If 235) also there is the point for not yet detecting, return to step 231 in set of characteristic points) continue to detect, otherwise turn
Step 234)；
236) from step 234) pointer straight line is selected in the set of characteristic points M of straight line that detects, according to the angle of straight line
And the center of circle is to the distance of straight line, the straight line that following condition is met in set of characteristic points M is found out：
Wherein, θiIt is straight line liAngle, diIt is the distance in the center of circle to straight line, θ0For differential seat angle threshold value, (and image resolution ratio has
Close, pixel is higher, value is smaller, can be typically 5% by error, be in this example minimax graduation mark differential seat angle 5%), D
For distance threshold (relevant with image resolution ratio, pixel is higher, and value is smaller, for the image of 600*400 pixel resolutions, can
It is set to 10).
If there is no pointer straight line, then (need to change the accumulator threshold parameter or straight length threshold value of Hough transform
Parameter) empty straight line set M；
If 237) accumulator threshold parameter N1Not less than the lower limit N of threshold value2, change accumulator threshold value N1=N1-N0, repeat
Step 231) -236), and until finding pointer straight line pair, terminate iteration, go to step 238)；Wherein N0It is accumulator threshold steps
(relevant with image resolution ratio, pixel is higher, and value is smaller, for the image of 600*400 pixel resolutions, can be set to 5)；
If accumulator threshold value N1Less than the lower limit N of threshold value2, still do not find pointer straight line pair, then change straight length
Threshold parameter；If straight length threshold value L1Not less than the lower limit L of threshold value2, change accumulator threshold parameter, L1=L1-L0, repeat
Step 231) -236), until finding pointer straight line pair, terminate iteration, wherein L0It is straight length threshold steps (and image point
Resolution is relevant, and pixel is higher, and value is smaller, for the image of 600*400 pixel resolutions, can be set to 5), go to step 238)；
If 238) in the case of i-th pair straight line, can find and meet step 233) in require pointer straight line to li, then this pair
Straight line is range scale line, and the instrument center of circle is two straight-line intersection P (x0,y0), minimum, maximum range straight line angle is respectively θmin,
θmax；
X=xi, y=yi
θmin=θ1i,θmax=θ2i
The instrument home position coordinate that will be found out, minimax range scale line angle degree is placed in ATL；
Step 3：Meter diagram to be identified is gathered, meter diagram to be identified is matched with the instrument Prototype drawing in ATL,
The corresponding Prototype drawing of meter diagram to be identified is found out, and meter diagram to be identified is corrected to positive visual angle figure, specifically include following step
Suddenly：
31) identification instrument two-dimensional image code, obtains the corresponding instrument ID values of the image, by the ID values of instrument in ATL
In find the Prototype drawing and meter parameter of the instrument.
32) according to meter diagram to be identified and its Prototype drawing, figure to be identified is corrected to front view：(due to actual photographed
Instrument picture to be identified is not that front view carries out Slant Rectify, it is necessary to treat identification instrument picture.Existing SIFT algorithms realize figure
As the matching of key point, and the key point obtained by matching, perspective transformation matrix is tried to achieve, figure to be identified is corrected to and is faced
Figure.) specifically include following steps (because the algorithm be image recognition in typical conventional algorithm, below describe directly reference
The content in books, without being explained in detail to term again)：
321) metric space extremum extracting
Metric space under different scale is obtained by the convolution of two-dimensional image I (x, y) and Gaussian kernel G (x, y, σ) and represents L
(x,y,σ)；Set up DOG (Difference-of-Gaussian) pyramid of image, 26 fields in DOG metric spaces
Middle detection extreme value, D (x, y, σ) is two differences of adjacent scalogram picture, i.e.,:
In D (x, y, σ)=(G (x, y, k σ)-G (x, y, σ)) × I (x, y)=L (x, y, k σ)-L (x, y, σ) formula:It is two-dimensional Gaussian function, wherein x, y represents the coordinate of picture point, σ represents Gauss
The variance of normal distribution, L (x, y, σ)=G (x, y, σ) × I (x, y) is the definition of metric space；
If if 18 neighborhood points of a point and eight points around and levels are maximums in totally 26 neighborhoods
Or minimum value, then the point is a characteristic point of the image under the yardstick.
322) key point is accurately positioned
Three-dimensional quadratic function is fitted accurately to determine position and the yardstick of key point by characteristic point, while removal is low right
Than the key feature points and unstable skirt response point of degree, to strengthen matching stability, improve noise resisting ability；
323) key point direction distribution
It is each key point assigned direction parameter using the gradient direction distribution characteristic of key point neighborhood territory pixel, makes operator
Possesses rotational invariance.
In formula:M (x, y) is the modulus value of (x, y) place gradient, and modulus value θ (x, y) is the direction of (x, y) place gradient, used by L
Yardstick be each key point each where yardstick.
324) generation SIFT feature vector
Reference axis is rotated into characteristic point direction, to ensure rotational invariance.In actual calculating process, in order to strengthen matching
Robustness, to each key point using 4 × 4 totally 16 seed points describe, so can just be produced for a key point
128 data, that is, ultimately form SIFT feature vector (i.e. feature descriptor) of 128 dimensions.SIFT feature descriptor to illumination, make an uproar
Sound, rotation and yardstick all have good consistency.
325) characteristic matching
After generating the SIFT feature vector of image, using the Euclidean distance of key point characteristic vector in two images as phase
Like sex determination measurement, certain key point in source images (template image) is taken, and find out it with Euclidean distance in image to be matched
Nearest the first two key point, in the two key points, if nearest distance is less than certain ratio divided by secondary near distance
Threshold value, then receive this pair of match points.
326) key point obtained according to matching, seeks perspective transformation matrix M；4 characteristic point positions of matching of Prototype drawing
(p0,q0), (p1,q1), (p2,q2), (p3,q3), 4 characteristic point position (u of matching of corresponding figure to be identified0,v0), u1,
v1), (u2,v2), (u3,v3), there is 3 × 3 perspective transformation matrix M relations between figure to be identified and Prototype drawing：
Wherein, aij(i=1,2,3；J=1,2,3) it is the occurrence of each element in perspective transformation matrix M.
Corresponding relation between 4 characteristic points of Prototype drawing and 4 characteristic points of figure to be identified is represented by：
Wherein i=0,1,2,3, w is parameter.
327) according to the transformation matrix tried to achieve, by each pixel point coordinates of figure to be identified according to above-mentioned transformation relation, obtain
To corresponding coordinate position and pixel value in the case of positive visual angle, figure to be identified is corrected to front view.
Step 4：Using the pointer lookup method of auto-adaptive parameter, the pointer straight line in meter diagram to be identified is searched, calculated
Meter reading；Step 4 with searched in step 2 as image cathetus algorithm is, except that step 2 needs to look for straight line
It is right, i.e., find minimax graduation mark simultaneously, step 4 only needs to look for gauge pointer straight line, thus in step 4 calculating parameter selection
The selection explanation that can refer to parameter in step 2 is carried out.
According to existing template picture in ATL is maximum, minimum range graduation mark angle, maximum, minimum range, only
The pointer being corrected in the instrument picture of front view need to be searched, and calculates pointer straight line angle, you can try to achieve meter reading.It is logical
The pointer straight line crossed during Hough transform searches meter diagram, specifically includes following steps：
41) point (x in random selection image point seti, yi), if not detecting the point also, the point is carried out
Hough is converted；
42) accumulator A (ri,βi) value be Ni, threshold value N1If, Ni≥N1, then correspondence parameter r is exportediAnd βi, then empty
Accumulator A (ri,βi)；
43) according to the straight line parameter for obtaining, the corresponding straight line l in original image of the point is found outk, and the straight line will be belonged to
Characteristic point all mark for detection；
44) straight line lkLength Lk, threshold value L1If, Lk≥L1, illustrate that the straight line for detecting meets accumulator parameter, length ginseng
Number threshold value, then record straight line lkIn set M；
If 45) also there is the point for not yet detecting, return to step 41 in point set) continue to detect；
46) need from step 44) pointer straight line is selected in the straight line set M that detects, according to the distance in the center of circle to straight line,
Meet di≤ D, finds out the pointer straight line in set M.Wherein, diIt is the distance in the center of circle to straight line, D is distance threshold.
If there is no pointer straight line, then need to change the accumulator threshold parameter or straight length threshold value of Hough transform
Parameter, empties straight line set M.
If 47) accumulator threshold parameter N1, straight length threshold parameter L1In the case of do not find out pointer straight line, as long as tired
Plus device threshold parameter N1Not less than the lower limit N of threshold value2, change accumulator threshold value N1=N1-N0, repeat step 41) -46), directly
To pointer straight line is found, terminate iteration.Wherein N0It is accumulator threshold steps；If accumulator threshold value N1Less than the lower limit of threshold value
N2, still do not find pointer straight line, then change straight length threshold parameter；If straight length threshold value L1Not less than under threshold value
Limit value L2, change accumulator threshold parameter, L1=L1-L0, repeat step 41) -46), until finding pointer straight line, terminate to change
Generation, wherein L0It is straight length threshold steps.
48) meter reading S is recognized,
Wherein θ is the angle of gauge pointer in figure to be identified, θmaxIt is the angle of maximum range graduation mark, θminIt is minimum
The angle of journey graduation mark, SmaxIt is maximum range, SminIt is minimum range.
Claims (4)
1. a kind of readings of pointer type meters automatic identifying method, it is characterised in that comprise the following steps：
1) collection and gauged instrument Prototype drawing, the instrument Prototype drawing is the positive visual angle figure to instrument, by instrument Prototype drawing, instrument mould
Gauge pointer current location reading in instrument minimax range, unit, and instrument template, is stored in ATL in plate figure
In；
2) maximum, minimum range graduation mark, the pointer straight line of instrument in Prototype drawing, and the minimax amount that will be calculated are searched
The angle of journey graduation mark, the home position of instrument dial are stored in ATL；
3) the instrument Prototype drawing in meter diagram to be identified and ATL is carried out into crucial Point matching, after obtaining perspective transformation matrix,
Meter diagram to be identified is corrected to positive visual angle figure；
4) using the pointer lookup method of auto-adaptive parameter, the pointer straight line in meter diagram to be identified is searched, calculates meter reading.
2. a kind of readings of pointer type meters automatic identifying method according to claim 1, it is characterised in that：Step 2) in most
The determination of the lookup method and home position of big minimum range graduation mark, according to following condition judgment, 1. minimax range is carved
Degree line, the relative angular difference of pointer straight line and the proportional relation of relative difference of reading；2. minimax range scale line, pointer straight line
Intersect at the center of circle；3. the lookup method of straight line uses auto-adaptive parameter lookup method；The minimax of instrument in every Prototype drawing
The lookup of range scale line and the determination of home position, specifically include following steps：
21) according to the Slope relationship of instrument minimax range scale straight line, to find out and meet Slope relationship in instrument Prototype drawing
Straight line pair, has n pairs；
22) according to the angle of every a pair of straight lines, and meter reading in minimax range, the Prototype drawing of instrument in Prototype drawing,
If it is minimax range scale line to calculate i-th pair straight line, the angle of template pointer is θ i, and the intersection point of i-th pair straight line is sat
Mark (xi,yi), i=0,1 ... n；
23) angle is θ i in searching instrument Prototype drawing, and by coordinate (xi,yi) straight line, if in the presence of such straight line,
I-th pair straight line is minimax range scale line, and the center of circle is (xi,yi), and by the angle, θ of maximum range graduation markmax, it is minimum
The angle, θ of range scale lineminAnd central coordinate of circle (xi,yi) be stored in ATL.
3. a kind of readings of pointer type meters automatic identifying method according to claim 1, it is characterised in that：Step 4) in from
The pointer lookup method of adaptation parameter, searches the pointer straight line in meter diagram to be identified, calculates meter reading, specifically includes：Know
During other meter reading, according to existing template picture maximum, the angle of minimum range graduation mark, maximum, minimum in ATL
Journey, lookup has been corrected to the pointer in the instrument picture of front view, and calculates its angle, that is, try to achieve meter reading as follows：
In formula, θ is the angle of gauge pointer in figure to be identified, θmaxIt is the angle of maximum range graduation mark, θminIt is minimum range
The angle of graduation mark, SmaxIt is maximum range reading, SminIt is minimum range reading, S is the reading of instrument in meter diagram to be identified；
The angle, θ of maximum range graduation markmax, minimum range graduation mark angle, θmin, maximum range Smax, minimum range Smin
It is the parameter that the instrument has been stored in ATL, only need to recognizes gauge pointer straight line and calculate its angle, θ, that is, tries to achieve instrument
Reading.
4. a kind of readings of pointer type meters automatic identifying method according to claim 1, it is characterised in that：Step 2) and step
It is rapid 4) in auto-adaptive parameter pointer lookup method, specifically include：
Linear equation y=kx+b in image space, is expressed as with polar form：R=xcos β+ysin β；Will ginseng
Number space is discrete to turn to A (ri,βi) accumulator element, to pixel (x in imagei, yi), carry out Hough transform, βiTraversal [0,
Centrifugal pump in π) is calculated ri, then A (ri,βi) value of accumulator element that represents adds 1；Specific steps include：
(1) point (x in random selection set of characteristic pointsi, yi), if not detecting the point also, Hough is carried out to the point
Conversion；
(2) if there is a certain accumulator A (ri,βi) value be more than or equal to threshold value N1, then correspondence parameter r is exportediAnd βi, then
Empty accumulator A (ri,βi)；
(3) according to the straight line parameter for obtaining, the corresponding straight line l in original image of the point is found outk, and the spy of the straight line will be belonged to
It is detection to levy a whole mark；
(4) straight line lkLength Lk, threshold value L1If, Lk≥L1, illustrate that the straight line for detecting meets accumulator parameter, length parameter threshold
Value, then record straight line lkIn set M；
(5) if also there is the point for not yet detecting in point set, return to step (1) continues to detect；
(6) pointer straight line is selected in the straight line set M for being detected from step (4), the angle or the center of circle according to straight line to straight line
Distance, find out the pointer straight line in set M；If there is no pointer straight line, then change the accumulator threshold value ginseng of Hough transform
Number or straight length threshold parameter, empty straight line set M；
(7) if accumulator threshold parameter N1, straight length threshold parameter L1In the case of do not find out pointer straight line, then accumulator threshold
Value parameter N1Not less than the lower limit N of threshold value2, change accumulator threshold value N1=N1-N0, repeat step (1)-(6), until finding
Pointer straight line, terminates iteration, wherein N0It is accumulator threshold steps；If accumulator threshold value N1Less than the lower limit N of threshold value2, still
Pointer straight line is not found, then changes straight length threshold parameter；If straight length threshold value L1Not less than the lower limit L of threshold value2,
Change accumulator threshold parameter, L1=L1-L0, iteration, wherein L, until finding pointer straight line, are terminated in repeat step (1)-(6)0
It is straight length threshold steps.
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