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Method for forming of image of sea vessel contour according to radar surveillances

Method for forming of image of sea vessel contour according to radar surveillances
IPC classes for russian patent Method for forming of image of sea vessel contour according to radar surveillances (RU 2308055):
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FIELD: control of motion of sea vessels for provision of safety of sea traffic.

SUBSTANCE: a matrix is formed that contains echo-signals from the target and from the surface sea waves, whose columns serve as radar observation rules corresponding to the angular positions of the radar antenna, a bipolar matrix of wavelet-spectra is obtained, the elements of the like polarity that don't contain wavelet spectra of the echo-signals from the sea vessel hull are excluded from the matrix of the wavelet-spectra, the value of the binomization threshold is determined, binomization of the matrix of the wavelet-spectra is accomplished, the vessel image is separated by processing of the binomized matrix of the wavelet-spectra by a morphological filter.

EFFECT: the image of the contour of the sea vessel is formed according to two-dimensional (angle-distance) radar surveillances at a complete suppression of the interference component from the disturbed sea surface.

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The invention relates to the field of motion control of marine vessels (hereinafter referred to courts), and is intended to form the image of the outline of a ship on radar observations with the aim of broadening the information base management systems, vessel traffic) in the interests of ensuring the safety of Maritime traffic.

One of the objectives of the VTS, in conditions of high traffic flows is ensuring traffic safety in places of a congestion of vessels in the Straits, on the fairways and ways of approach of vessels to ports. The main conditions for safe movement are: the prevention of an excessive convergence of vessels up to some critical value that defines the security zone around the vessel and referred to as "ship domain, as well as having current information about the intentions of each vessel.

Traditionally ship domain is the area around the vessel specified radius, the shape and dimensions of which do not take into account the geometry of the actual size and the current ship's course. While the ship's course is determined by assessing the velocity vector on radar observations during several revolutions of the antenna, which indicates the delay information about the direction and nature of the motion of the ship.

In conditions of high traffic intensity in places where the ship is essential for monitoring the actual convergence of the courts (the shortest distance between the nearest points of hull) plays information about the geometric characteristics (length and width of the vessel) and the orientation of buildings ships in the current time.

In VTS similar information can be obtained during the administration of courts by drawing a profile of the hull of each vessel in the horizontal plane (hereinafter - the contour of the vessel) to a two-dimensional (angle-distance) radar observations derived from radar observations during one revolution of the antenna, which provides VTS information about the length, width and rate (angular position of the longitudinal axis of the path of each vessel, respectively, of the actual approach of vessels in real time.

In General, radar observations generated during one revolution of the antenna at the system output selection of moving targets (MTI) radar station (including analog-to-digital Converter - ADC)represent the matrix of the echo signals, the columns of which are formed from radar lines of observations. Radar range of observations for each angular position of the antenna is a sequence of discrete samples of the echo signal at the ADC output. The matrix of the echo signals is generated for each vessel (hereinafter - ship), which is the location of the VTS.

The matrix of the echo signals contains two main components: the echo signals from the hull and from the surface of the sea, which determine the structural basis for the formation of the image of the contour of the vessel.

Echoes from the surface of the sea, which are the obstacles that exclude the possibility of directly obtaining from the matrix of the echo signals information about the length, width and course of the vessel. This requires special methods of forming the image of the contour of the vessel on radar observations.

Discuss first used further definition of the coherent field, binominal and morphological image processing.

A connected region is a compact set of pixels, each pixel of which has at least one neighbor that belongs to this set. Pixel - picture element, in this case the matrix element.

Binominal transformation matrix with elements of arbitrary values in a matrix of binary values (the elements of the matrix contain 1 or 0) using the specified threshold.

Morphological processing biometerology matrix using two-dimensional morphological filter exception of a connected region biometerology matrix whose size is smaller than the two-dimensional matrix of morphological filter.

A known method of extraction of object boundaries grayscale images [1] using Sobel filters, Previte, Roberts, Canny, by means of which form the image of the contour of the target two-dimensional (angle-distance) radar observations by convolution matrix on which ludeni with mask (two-dimensional matrix) of these filters.

A two-dimensional matrix filter has a Central element. Procedure convolution (filtering) is performed by sequentially moving the matrix of the filter so that its Central element in turn is aligned with all the elements of the matrix of the echo signals. In each of these provisions is the summation element-by-element multiplication of the matrix elements of the filter matrix elements of the echo signals which coincide with the elements of the matrix filter. If the resulting sum exceeds a predetermined threshold value, then the element of the output matrix (the matrix of the image contour goals resulting from convolution matrix of the echo signals with matrix filter), the coordinates (row number, column number) coincide with the coordinates of the Central element of the mask is set to 1, otherwise 0.

The main disadvantage of this method is that the image of the contour of a vessel distorted noise from disturbing the surface of the sea. This is explained by the fact that the radar echo signals in addition to the echo signals from the ship's hull also contain echoes from the rough sea surface, which in this case are treated as interference. Applying Sobel filters, Previte, Roberts, Canny reduces the noise level by summing up why cementnogo multiplication of matrix elements of the filter matrix elements of the echo signals, which coincide with the elements of the matrix filter, but not completely eliminates interference from a rough sea surface on the image of the contour of the vessel. Thus, the method does not contain procedures, eliminating the above mentioned disadvantages.

Thus, the method of extraction of object boundaries halftone images may not be used to form the image of the outline of a ship in full suppression of the noise components from the rough sea surface.

The known method [2], path selection on radar image based on wavelet transform, which from a matrix containing echoes from the rough sea surface and the echo signals from a radar target, the columns of which are radar rulers of observations, corresponding to angular positions of the radar antenna, get the image path of a radar target by forming a bipolar matrix of wavelet spectra of columns of the matrix of the echo signals.

Consider the method uses the property of wavelets, according to which they have both temporal and frequency localization, i.e. using wavelets can be distinguished local spatial heterogeneity of signal (loop target), using the frequency properties of a wavelet as f is of ltr with adjustable parameters. This method is implemented in discrete form (as the observations after the ADC are discrete) continuous wavelet transform in the form of a high-frequency filter, which is scalable procedure of differentiation (separation circuit purpose), implemented by the convolution of columns (lines) of the matrix of the echo signals with the psi-function of a wavelet for a given scale (j) of the wavelet.

The psi-function of a wavelet is a vector, the sum of whose elements are zero, because the elements of the first half of the vector are positive values, and elements of the second negative. During convolution with elements of radar range of the observation vector of the psi-function sequentially moves along a line so that the initial element of the vector in turn is aligned with the line. In each of these provisions of the vector of the psi-function of its elements are multiplied with the elements of line, but the result of the multiplication are added up. The result of the sum is assigned to the element of the resulting line (the line obtained as a result of this wavelet transform), whose coordinates match the coordinates of the first vector element of the psi-function.

Thus, during successive movements of the psi-function along the line for each position of the psi-function of the mouth of the selected value of the difference between two adjacent samples of the line (coincident with the first and second halves of the vector elements of the psi-function) the size of which increases with j.

The result indicated a convolution of the psi-function of a wavelet with the echo signals from the body of radar targets are the wavelet spectra in the form of unipolar pulses, the position of which each line corresponds to the position of the echo signals reflected from the element body of radar targets, then multiple output lines forms the matrix of wavelet spectra, which referred to unipolar pulses form the external contour of the housing of the radar target.

The result of the convolution of the psi-function of a wavelet with the echo-signals from the surface of the sea is the wavelet spectrum interference in the form of a random bipolar pulses.

Thus, in General, the matrix of wavelet spectra of the echo signals, representing the sum of the wavelet spectra of the echo signals from the body of radar targets and surface commotion is bipolar matrix of wavelet spectra.

With the growth of the parameter j increases the sizes mentioned previously adjacent samples, i.e. increases averaging effect on the interfering component, the variance of the wavelet spectrum which as a consequence, with increasing j is reduced. At the same time the amplitude of the wavelet spectra of the echo signals from the body of radar targets with growth parameter j increases. Choosing the optimal value j, achieve better extraction of the contour of the housing of the radar target. To reduce interference to the wavelet spectra adaptive threshold is applied.

The main disadvantage of this method is that the image of the contour of a vessel distorted noise from disturbing the surface of the sea.

This disadvantage is due to the fact that during the convolution of the psi-function of a wavelet with columns (lines) of the matrix echo averaging effect of the wavelet on the random component of the noise is expressed only in reducing the variance of the noise components and does not eliminate it completely. Adaptive threshold limits of the elements of the wavelet spectra is focused on maintaining only a given level of false alarms and does not allow to completely suppress the interfering component.

While following the above method prototype of the bipolar matrix of wavelet spectra of the echo signals do not exclude elements of the same polarity that does not contain the wavelet spectra of the echo signals from the ship's hull, do not set the threshold value of binominal, in which the sizes of connected sets minorityowned elements of the wavelet spectra of the echo signals from surface disturbances smaller than a two-dimensional matrix of morphological filter, do not binomial matrix of wavelet spectra of the echo signals using the plant threshold binominal, providing the exception of elements of the wavelet spectra of the echo signals from the rough sea surface, using the morphological filter by morphological processing formed biometerology matrix of wavelet spectra do not receive the wavelet spectra of the echo signals in the form of unipolar pulses, the position of which on each radar range observation corresponds to the position of the echo signals from the reflecting element of the hull and which form the outer contour of the hull of a vessel.

Thus, the path selection on radar image based on the wavelet transform cannot be used to form the image of the outline of a ship in full suppression of the noise components from the rough sea surface.

Therefore, there remains the unresolved issue of drawing a contour of a vessel on a two-dimensional (angle-distance) radar observations in the complete suppression of the noise components from the rough sea surface.

There is a method of path selection on radar image based on wavelet preobrazovaniya, according to its technical nature, functionality and achieved technical result is the closest to the claimed invention a method is formirovaniya image of the outline of a ship on radar observations and considered further as the prototype method.

The basis of the invention is to provide a method of forming an image of the outline of a ship on radar observations in the complete suppression of the noise components from the rough sea surface. This takes into account that the main information elements, which provides the contour of the vessel, are length, width and rate (spatial orientation of the longitudinal axis of symmetry of the contour of the vessel) vessel.

The problem is solved in that in the method of forming the image of the outline of a ship on radar observations, which form a matrix containing the echo signals from the hull of the marine vessel and from the surface of the sea, the columns of which are radar rulers observations for each angular position of the antenna, which is a sequence of discrete samples of the echo signals, for each i-th line where i=1,2,...,q - line, receive bipolar matrix of wavelet spectra of the echo signals using the continuous wavelet transform of the columns of the matrix of the echo signals, advanced bipolar matrix the wavelet spectra of the echo signals exclude elements of the same polarity that does not contain the wavelet spectra of the echo signals from the ship's hull, set the threshold value of binominal, in which the sizes of connected sets minimizer the bathrooms of the elements of the wavelet spectra of the echo signals from surface disturbances smaller than a two-dimensional matrix of morphological filter, perform binomial matrix of wavelet spectra of the echo signal with the threshold set binominal providing the exception of elements of the wavelet spectra of the echo signals from the rough sea surface, using the morphological filter by morphological processing formed biometerology matrix of wavelet spectra have the wavelet spectra of the echo signals in the form of unipolar pulses, the position of which on each radar range observation corresponds to the position of the echo signals from the reflecting element of the hull and which form the outer contour of the hull of a vessel.

The inventive method of forming a contour of a vessel on radar observations of the total essential signs for him and for his method of the prototype are:

- formation of a matrix that contains the echo signals from the hull of the marine vessel and from the surface of the sea, the columns of which are radar rulers observations for each angular position of the antenna, which is a sequence of discrete samples of the echo signals, for each i-th line where i=1,2,...,q - number line;

- getting bipolar matrix of wavelet spectra of the echo signals using the continuous wavelet transform of the columns of the matrix of the echo signals.

Comparative EN is Liz essential features of the claimed method and the method of the prototype shows first, unlike the prototype method has the following salient features:

- exclusion from bipolar matrix of wavelet spectra of the echo signal elements of the same polarity that does not contain the wavelet spectra of the echo signals from the ship's hull;

- determining the value of the threshold binominal, in which the sizes of connected sets minorityowned elements of the wavelet spectra of the echo signals from surface disturbances smaller than a two-dimensional matrix of morphological filter;

- execution of binominal matrix of wavelet spectra of the echo signal with the threshold set binominal providing the exception of elements of the wavelet spectra of the echo signals from disturbing the surface of the sea,

obtaining, using the specified morphological filter (by morphological processing formed biometerology matrix) wavelet spectra of the echo signals in the form of unipolar pulses, the position of which on each radar range observation corresponds to the position of the echo signals from the reflecting element of the hull and which form the outer contour of the hull of a vessel.

The set of features that ensure the achievement of the technical result:

- formation of a matrix that contains the echo signals from the hull of the marine vessel and surface commotion is orya, columns which are radar rulers observations for each angular position of the antenna, which is a sequence of discrete samples of the echo signals, for each i-th line where i=1,2,...,q - number line;

- getting bipolar matrix of wavelet spectra of the echo signals using the continuous wavelet transform of the columns of the matrix echoes;

- exclusion from bipolar matrix of wavelet spectra of the echo signal elements of the same polarity that does not contain the wavelet spectra of the echo signals from the ship's hull;

- determining the value of the threshold binominal, in which the sizes of connected sets minorityowned elements of the wavelet spectra of the echo signals from surface disturbances smaller than a two-dimensional matrix of morphological filter;

- execution of binominal matrix of wavelet spectra of the echo signal with the threshold set binominal providing the exception of elements of the wavelet spectra of the echo signals from disturbing the surface of the sea,

obtaining, using the specified morphological filter (by morphological processing formed biometerology matrix) wavelet spectra of the echo signals in the form of unipolar pulses, the position of which on each radar range observation corresponds to the position of the echo signals reflect from the element of the hull and which form the outer contour of the hull of a vessel.

The technical result from the use of the inventive method of forming the image of the outline of a ship on radar observations is to obtain information about the geometric dimensions and the angular position of the longitudinal axis of the contour of the vessel under full suppression of the noise components from the rough sea surface on the image of the contour of a vessel.

This combination of well-known and distinctive essential features sufficient and necessary to achieve the claimed technical result.

Based on the above we can conclude that the set of essential features of the claimed invention has a causal relationship with achievable technical result, i.e. due to the essential features of the invention it has become possible to solve the problem.

Therefore, the claimed invention is new, involves an inventive step, i.e. it is not obvious from the prior art and suitable for industrial applications.

The essence of the claimed method of forming the image of the contour of a vessel on radar observations, illustrated by drawings:

figure 1. The appearance of the matrix echoes;

- 2. The appearance of a binary matrix of wavelet spectra of the echo signals from the ship's hull after processing m is ufologicheskiy filter.

- 3. The outline of a ship.

The claimed method of forming the image of the outline of a ship on radar observations is implemented by the step 1 of forming a matrix that contains the echo signals from the hull of the marine vessel and from the surface of the sea (figure 1), the columns of which are radar rulers observations for each angular position of the antenna, which is a sequence of discrete samples of the echo signals, for each i-th line where i=1,2,...,q - number line; operation 2 receive bipolar matrix of wavelet spectra of the echo signals using the continuous wavelet transform of the columns of the matrix of the echo signals; operation 3 exceptions bipolar matrix of wavelet spectra of the echo signal elements of the same polarity that does not contain the wavelet spectra of the echo signals from the ship's hull; a step 4 set the threshold binominal, in which the sizes of connected sets minorityowned elements of the wavelet spectra of the echo signals from surface disturbances smaller than a two-dimensional matrix of morphological filter; operation 5 run binominal matrix of wavelet spectra of the echo signal with the threshold set binominal providing the exception of elements of the wavelet spectra of the echo signals from disturbing the surface of the sea; operation 6 floor is to be placed with specified morphological filter (by morphological processing formed biometerology matrix) wavelet spectra of the echo signals in the form of unipolar pulses (figure 2), the position on which each radar range observation corresponds to the position of the echo signals from the reflecting element of the hull and which form the outer contour of the hull of the marine vessel (figure 3).

The implementation of the inventive method of forming the image of the outline of a ship on radar observations is as follows.

In accordance with the regulations for the safe navigation of vessels minimum distance between vessels may not be less than their ship domain, i.e. between the courts always have guaranteed the distance, not employed by the courts. While MTI performs "target lock" so that the check mark from the target (ship) is always in the center of the two-dimensional sample (angle-distance) radar observations. The sample selected by the ADC and corresponding to a certain angular position of the antenna in this case is part of a radar range of observations (next - line).

Therefore, the matrix of the echo signals (operation 1)obtained during one revolution of the radar antenna, contains in the Central part of the elements whose values are equal to the sum of the echo signals from the ship's hull and the surface of the sea, the rest of the elements of the matrix contains only the echoes from the surface of the sea.

The rulers are suitable which x each angular position of the antenna, is a matrix of echoes

where Z0(k, i) - matrix of the echo signals from the hull of the ship; ε(k, i) - matrix of the echo signals (noise) from disturbing the surface of the sea;- the sequence number of the reference ADC on the ruler; n is the maximum number of ADC counts on the ruler; i=1,2,...,q - line, q - selected number of lines in the matrix Z.

For each i-th line is formed wavelet transform using the discrete form of the continuous wavelet transform [3]

where ψ0basic psi-function of the wavelet; j is the scale parameter;- coordinate position of the psi-function on the line; h is the number of vector elements of the psi-function ψ0.

The continuous wavelet transform provides a scalable procedure for the differentiation implemented by convolution column of the matrix Z (rulers) and the psi-function ψ0in the course of which set the value of the difference between two adjacent samples, the size of which increases with j, and the weight factors of the elements of the samples in the bundle are determined by the psi-function ψ0. With the growth of the parameter j increases the sizes of adjacent samples, i.e. increases averaging effect on the interfering component, the value of dispersively spectrum which as a consequence, with increasing j is reduced. At the same time the amplitude of the wavelet spectra of the echo signals from the ship's hull with the growth parameter j increases. That said, the envelope of the wavelet spectrum of the echo signals from the ship's hull is characterized by a change from zero to saturation (max) and again to zero, the more the parameter j, the wider the region of saturation. The saturation region of (given ψ0and j) is a measure of the uncertainty of the coordinates in the radar line of the wavelet spectrum of the echo signal from the hull.

The result of the convolution (2) of the psi-function ψ0the columns of the matrix Z0(k, i) are the wavelet spectra of the echo signals from the ship's hull in the form of negative pulses with amplitude Ucand a width equal to the saturation region, whose position in each i-th line corresponds to (including measures of uncertainty) the position of the leading edge of the rectangular pulse echo signal irradiated from the radar of the ship's hull. In the future many pulses Ucdefines the geometry of the contour of the vessel.

The result of the convolution (2) of the psi-function ψ0the columns of the matrix ε(k,i) of the echo signals from the rough sea surface is the wavelet spectrum interference in the form of a bipolar matrix elements Withi(b, j), the value of which increases with the amplitude of the echo signals from the rough sea surface and decreases as Sazanovich, with increasing scale parameter j.

Further, the vectors of wavelet spectrum (2) for the selected j are grouped in bipolar matrix Withj(b,i); i=1,2,...,q;(operation 2).

Due to the fact that positive values of the matrix elements Withj(b, i) does not carry the information about the contour of the vessel (pulses Uchave a negative polarity and are omegawiki components of the wavelet spectrum, then subsequently treated with a matrix Withj(b,i)-in which positive elements (noise components) of the matrix Withj(b,i) are replaced by zero values (operation 3).

This trick is one of the distinctive elements of the method of forming the image of the outline of a ship on the basis of reducing the connectivity of the elements of the matrix of wavelet spectra. Its essence lies in the fact that after the exclusion of the positive elements of the matrix Cj(bi) destroys the coherence of the bipolar elements of the wavelet spectrum interference, as the positive elements of ECM components are replaced with zero values - zero elements destroy the connectivity of the wavelet spectra of the interference.

At the same time in all lines of negative pulses Uccarrying the information about the geometry of the hull, preserved and their connectivity is not broken.

A specific value scale j for a given psi-function È 0is selected as the maximum ratio of quantities of pulse amplitudes Ucto the dispersion of the wavelet spectrum of the interference.

Further, for brevity matrix of wavelet spectra indicatedwhere abs(.- the operator absolute value.

From the matrix of wavelet spectra is selected that part of itthat contains only the wavelet spectra of the interference. As the observations (1) is formed in such a way that the echo signals from the ship's hull are located in the Central part of the matrix Z (k,i), respectively, it is possible to select the part of the matrix of wavelet spectra, which obviously does not contain the wavelet spectra of the echo signals from the ship's hull.

Note that the statistical characteristics of the surface of the sea is determined by the intensity of wind influence and characteristics of waters that do not change within the local region, forming radar observations recorded in the matrix of the echo signals. Therefore, the selected matrix has a statistical representation of the wavelet spectrum interference for the whole matrix With the wavelet spectra of the echo signals.

Another distinctive element of the method of forming the image of the contour of the marine vessel based on the reduction of connectivity elements jamming of componentiality With is the determination of the threshold of binominal p (operation 4), adaptive to the level of the wavelet spectrum interference to the type of the psi-function ψ0the value of the scale j and the two-dimensional size of the morphological filter. Since the statistical characteristics of the wavelet spectrum interference matrixrepresentative in relation to the entire matrix of wavelet spectra, the establishment of a threshold R for the matrixtrue also with respect to the matrix of wavelet spectra interference With.

The decrease in connectivity by applying a threshold of p is due to the fact that some non-zero component of disturbances matrixremaining after the operation 3, receives a zero value in the process of binominal matrixlevel R. this procedure is denoted by the operator In

where,,the matrix element.

The procedure for setting the threshold value of binominal, in which the sizes of connected sets minorityowned elements of the wavelet spectra of the echo signals from surface disturbances smaller than a two-dimensional matrix of morphological filter (operation 4), includes morphological processing binary matricially-spectrum interference using two-dimensional morphological filter (morphological filter [4]).

This procedure will denote the operator M

Because the amplitude of the wavelet spectrum of the noise is random (due to the random nature of the echo signals from the excited surface), the values of the elements of the matrixwhen the selected dimensions c×c two-dimensional matrix of morphological filter depend on the size of the threshold R. the larger the threshold R, the smaller the coherence of sets minorityowned elements of the wavelet spectra of the interference and, consequently, smaller values of the matrix elementsand, conversely, the smaller the threshold R, the greater the connectivity sets minorityowned elements of the wavelet spectra of the noise and, accordingly, the greater values of the matrix elements.

The optimal threshold value p is determined in the course of solving optimization problems

wherethe target function of the optimization problem;- the elements of the matrix. Under optimal threshold value equal to R*the sizes of connected sets minorityowned elements of the wavelet spectra of the echo signals from surface disturbances less p is Smurov two-dimensional matrix of morphological filter, that provides a complete elimination of the elements of the wavelet spectrum interference from the matrix.

Further, during the operation 5 is similar to rule (3) is binominal matrix of wavelet spectra using the obtained optimal threshold binominal R*.

Due to substantiated earlier the representativeness of the statistical characteristics of the wavelet spectra of the interference matricesand With the sizes of connected sets of elements of the wavelet spectra of the interference biometerology matrix With will also be smaller than the two-dimensional morphological filter that will ensure the complete suppression of the interference matrix With the result of morphological processing elements of its wavelet spectrum. While many elements of a matrix WithIn(R*) ={C(R*)}containing component Uwiththe wavelet transform of the echo signals from the ship's hull, in contrast to the wavelet spectrum interference, maintain connectivity. Therefore, in the course of morphological processing (operation 6)performed a morphological filter is a matrix

the elements which form the image of the contour of a vessel.

Thus, the image formation path of a ship running at full suppression of the echo noise components from the surface is chastnogo rough seas.

Currently, the device implementing the claimed method, is in the stage of prototyping. Layout made with regard to coastal radar-round overview of the VTS Center Vladivostok.

Characteristics of the radar and the ship:

- the beam width of the antenna - 0,39°;

- the sampling frequency of the ADC of the echo signal at the output of the VMD radar - 75 MHz (linear interval of sampling observations 2 m);

- dimensions of the vessel: length is 160 m, width - 28 m;

- the ship's course - 45°;

- the distance of the vessel is 1000 m;

the angular step of the antenna between two adjacent radar line - of 0.03°.

We form the matrix layout of the echo signals (1) as the sum of principal components: the echo signals from the ship's hull (Z0and reflection from the surface of the sea (ε).

The distribution of the probability density of the effective area of the radar cross section (RCS) of these reflectors is described [5]:

exponential law for the EPR (S0) echo signals from the ship's hull.

where- the average value of the ESR of the hull in the angular sector of the antenna directional diagram;

- Fabulous.com distribution for EPR (Sε.) the surface of the sea

where c'=1/b' - pairs of the Tr form, G - the median value of the distribution, defined by the intensity of emotion.

Select model parameters=1,0, c'=0,57, G=0.8 and, whereaslet's form [5] in the specified proportions matrix of the echo signals from the ship's hull and the surface of the sea (figure 1). As follows from figure 1, the echo signals from the ship's hull is significantly distorted by the high level of interference from disturbing the surface of the sea.

Generate the matrix of wavelet spectra at a given scale j=3, maximizing the relationship of the amplitude of the pulses Ucto the dispersion of the wavelet spectrum interference, and the psi-function ψ0wavelet Daubechies 'db1' [3], having a maximum linear resolution, which allows to minimize the previously mentioned region of saturation, which is a measure of the uncertainty of the coordinates of the contour of the vessel.

Select morphological filter bwmorph, type='majority' [4] with the dimensions of the two-dimensional filter c×=3×3 and the parameter f=5 with maximum resolution that also achieves high precision imaging path of the vessel.

The result of simulation of the solution of optimization problem (5) on the matrixformed from the initial fragments of lines of the matrix S, which obviously contain only the wavelet spectrum of the s interference, set for this model situation, the optimal value of the threshold binominal R*=0,335.

Applying a threshold of p*binominal matrix of wavelet spectra of the entire matrix is followed by performing morphological processing by the selected filter allows you to completely suppress the background noise and at the same time to form a binary matrix WithBM(figure 2). MatrixBMis the figure formed from a single element in a horizontal plane to form the contour of the vessel (figure 3).

As a matrix WithBMis the figure formed from a single element, the specified shape in the horizontal plane has both external and internal boundaries, the distance between kotorii is equal to the width of the previously mentioned areas of saturation (pulse width Uc) and the corresponding measure of uncertainty, which is given ψ0and j for a given model of the situation does not exceed 4 m

Near to the radar part of the hull is a continuous reflecting surface ship, the image of the contour of the horizontal plane represented by continuous curves 1 and 2. The distant part of the hull is in the area of radar shadow, so when prototyping provides that the sources of formation of the Ho-signals in this case are separate irradiated radar reflectors, simulating the bulwarks and guard rails deck, located on the top edge of the far side. This explains the fragmentary outline of the distant ship (curves 3 and 4).

No fragments of the contour of the back of the hull aft of the vessel mimics the on-screen action aft superstructures, the circuit 5 which merges with the image of the contour 2 in the aft part of the ship.

It should be noted that the presence of internal and external borders of the figure formed by individual elements of the matrix C does not distort the shape of the contour of the vessel and does not introduce errors in the determination of the size and course of the vessel. So, curves 1 and 3 or 2 and 4, taken in pairs, form the image of the contour of the vessel, allowing to determine the size and direction of the vessel. While this uncertainty has an impact only on the determination of the exact distance to the vessel, the sensing error which in this model situation does not exceed 2 meters (half a measure of uncertainty), which is 0.2% (the distance from the vessel in this case is equal to 1000 m).

The image of the contour of the vessel has a stepped appearance, due to the discrete nature of the formation of lines of observations by the ADC.

Further reduction of the step angle of the radar antenna and increase the sampling frequency of the ADC allows to increase the number of elements in the matrix of the echo signals and thereby reduce the size of the steps and to bring the formed image of the contour of the vessel to the true profile of its body in a horizontal plane.

The modeling confirms the possibility of drawing a contour of the vessel and determine on the basis of size (length 160 m, width - 28 m) and the rate To the vessel coincides with the longitudinal axis of symmetry of the circuit 6, which in this case is 45° relative to the direction to the North. The background noise from the rough sea surface on the image of the contour of the vessel completely suppressed.

Thus, the obtained results confirm the achievement of the technical result from the use of the inventive method of forming the image of the outline of a ship on radar observations, which consists in obtaining information about the geometric dimensions and the angular position of the longitudinal axis of the contour of the vessel under full suppression of the noise components from the rough sea surface on the image of the contour of a vessel.

Sources of information

1. Rudakov P.I., Safonov I. Processing of signals and images. MATLAB 5.x/ pod obshch. Red. Vgotin. M: DIALOG-MIFI. 2000. 416 S. - EQUIVALENT.

2. Yang Li, Yuan Xin. An Edge Detector Based On Wavelet Transform For SAR Image.// Trans. Nanjing Univ. Aeron. and Astron. 2001. Vol.8, No. 1. P.75-80 PROTOTYPE.

3. Deacons VP Wavelets. From theory to practice. M: SALTY-R, 2002. 448 S.

4. Deacons VP MATLAB. Processing of signals and images. Special guide. SPb.: Peter. 2002. 608 S.

5. Dorozhko V.M., Simulation model of radiologic the district of the echo signal. // Far Eastern mathematical journal, 2000, vol. 2,1. P.98-113.

The method of forming the image of the outline of a ship on radar observations, namely, that form a matrix containing the echo signals from the hull of the marine vessel and from the surface of the sea, the columns of which are radar rulers observations for each angular position of the antenna, which is a sequence of discrete samples of the echo signals, for each i-th line where i=1,2,...,q - line, receive bipolar matrix of wavelet spectra of the echo signals using the continuous wavelet transform of the columns of the matrix of the echo signals, characterized in that the bipolar matrix of wavelet spectra of the echoes exclude elements of the same polarity that does not contain the wavelet spectra of the echo signals from the ship's hull, set the threshold value of binominal, in which the sizes of connected sets minorityowned elements of the wavelet spectra of the echo signals from surface disturbances smaller than a two-dimensional matrix of morphological filter, perform binomial matrix of wavelet spectra of the echo signal with the threshold set binominal providing the exception of elements of the wavelet spectra of the echo signals from the rough sea surface, using the specified morfologica the who filter through morphological processing formed biometerology matrix of wavelet spectra have the wavelet spectra of the echo signals in the form of unipolar pulses, the position on which each radar range observation corresponds to the position of the echo signals from the reflecting element of the hull and which form the outer contour of the hull of a vessel.

 

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