A method for constructing one-dimensional range image features of a ship target

Abstract

The application provides a one-dimensional range image feature construction method of a ship target, and specifically comprises the following steps: step 1: analyzing one-dimensional range image echo data; step 1.1: reading the one-dimensional range image echo, and completing calibration constant correction according to external calibration information to display ship target region signals; step 1.2: performing signal transformation on the ship target region signals, that is, converting the time domain into the frequency domain to describe the transform domain features of the ship target; step 2: extracting the statistical quantity features of the ship target; step 3: extracting the angle features of the target; and step 4: extracting the time features of the target, including amplitude normalization processing, translation compensation and time alignment, target motion time sorting and time variation features. The method combines amplitude and phase information and the construction of the statistical quantity features, angle features and time features of the one-dimensional range image of the ship target to generate a complete representation of the characteristics of the ship target, and has great significance for ship target recognition.

Description

Technical Field

[0001] This invention relates to the field of electronic information technology and radar technology, and in particular to a method for constructing one-dimensional range profile features of ship targets. Background Technology

[0002] One-dimensional range profiles are widely used in radar automatic target identification. The basis for target identification is the in-depth analysis of the collected target data to construct a comprehensive and complete set of target features. As a very important type of maritime target, ship targets are of great significance for identifying them by extracting their feature information using radar one-dimensional range profiles.

[0003] Typically, processing of one-dimensional range profiles only utilizes the amplitude information of the echoes, while the extraction of information such as the echo phase is still lacking. A one-dimensional range profile that combines amplitude and phase information provides a complete representation of the target's characteristics. For specific targets such as ships, it is necessary not only to perform statistical analysis on characteristics such as amplitude and phase, but also to extract their variation characteristics with angle and time, thereby constructing a complete target characteristic database. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a method for constructing one-dimensional range profile features of ship targets, overcoming the shortcomings of existing one-dimensional range profile feature extraction methods, which fail to acquire features perfectly and cannot comprehensively characterize the target's properties.

[0005] This invention provides a method for constructing a one-dimensional range profile feature of a ship target, specifically including:

[0006] Step 1: Analyze the one-dimensional range image echo data;

[0007] Step 1.1: Read the one-dimensional range image echo, and complete the calibration constant correction according to the external calibration information to display the ship target area signal;

[0008] Step 1.2: Perform signal transformation on the ship target area signal, that is, describe the transform domain characteristics of the ship target through time-domain and frequency-domain transformation;

[0009] Step 2: Extract statistical features of ship targets; including one-dimensional range profile peak value, peak width, mean, variance, and range fluctuation features.

[0010] Step 3: Extract the angular features of the target and construct the angular change feature quantity of the ship target, including amplitude normalization processing, translation compensation, azimuth attitude angle sorting, and angular change features;

[0011] Step 4: Extract the target's temporal features, including amplitude normalization, translation compensation and time alignment, target motion time sorting, and time change features.

[0012] Furthermore, in step 2:

[0013] Step 2.1: Construction of peak value and peak width characteristic statistics;

[0014] Wherein: the peak value refers to the local maximum point in the range direction. The amplitude of each range unit in the range direction is compared with the two units to its left and right. The maximum amplitude is the peak value. The peak width is calculated by the difference between the start and end positions of the peak.

[0015] Step 2.2: Construct the mean peak width of the one-dimensional range image of the ship's target region from the ship's echo sequence. shd ) and peak width variance (Var shd );

[0016]

[0017]

[0018] Where x i Where is the crest width and N is the number of crests;

[0019] Step 2.3: Construct distance image undulation features;

[0020] Among them: the difference in the distribution of scattering centers will cause the range cell echo to fluctuate to varying degrees; let the range image in the m-th azimuth domain of the target be {x}. cml |l=1,2,…,L}, the corresponding average distance image μ cm =[μ cm (1)…μ cm (N)] T variance image in Let μ cm The support region is [n cm0 The weighted vector of the distance image within the angular domain [ncm] is obtained as follows: within the support region, the weight is taken as the reciprocal of the standard deviation of the corresponding distance cell; outside the support region, the weight is set to zero.

[0021]

[0022] The distance-weighted fluctuation feature is defined as:

[0023] v cmL =x cmL w cmL

[0024] The range image fluctuation feature obtained by the above formula includes both the absolute amplitude of the sample and reflects the fluctuation of the range cell echo as the target attitude changes.

[0025] Furthermore, in step 3:

[0026] Step 3.1: Extract one-dimensional range signals according to angles, and perform amplitude normalization on the one-dimensional range image signals of the ship target. That is, amplitude normalization normalizes each one-dimensional range image using its maximum amplitude; as shown in the following formula:

[0027]

[0028] Step 3.2: Perform translation compensation based on the ship target's speed and time, ensuring that the target displayed in the one-dimensional range image remains centered as the angle changes;

[0029] Step 3.3: Use the range image matching method to estimate the target attitude angle. Divide the attitude range to be estimated into N regions according to the required attitude accuracy. Pre-store the target range image templates for each region. Match the real-time obtained range images with the templates. Obtain the attitude angle estimate according to a certain discriminant function. Sort the attitude angles according to their size to obtain the azimuth attitude angle sorting features.

[0030] Step 3.4: Construct the characteristic quantities of ship target angle change according to the ship target angle change law.

[0031] Furthermore, in step 4:

[0032] Step 4.1: Extract the one-dimensional range image signal of the ship target according to time, and perform amplitude normalization on the one-dimensional range image signal of the ship target. That is, amplitude normalization is performed on each one-dimensional range image using its maximum amplitude; as shown in the following formula:

[0033]

[0034] Step 4.2: Perform translation compensation on the range image based on the time-averaged zero-phase representation method to achieve time alignment;

[0035] Step 4.3: Sort the targets according to their motion duration to construct target motion time features;

[0036] Step 4.4: Construct the characteristics of ship target changes over time based on the time changes of the ship target. The beneficial effects of this invention are:

[0037] (1) For one-dimensional range image radar data of ship targets, extract multiple features such as target statistical features, time and angle change features, etc., to achieve a comprehensive description of ship targets and provide effective input for target identification.

[0038] (2) This invention proposes to generate a complete characterization of ship target characteristics by analyzing one-dimensional range image echo data, combining amplitude and phase information with the construction of statistical features, angle features and time features of one-dimensional range image of ship target, which is of great significance for ship target identification. Attached Figure Description

[0039] Figure 1 This is a flowchart of a method for constructing one-dimensional range profile features of a ship target according to an embodiment of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0041] like Figure 1 As shown, this embodiment provides a method for constructing a one-dimensional range profile feature of a ship target, specifically including:

[0042] Step 1: Analyze the one-dimensional range image echo data. The specific steps are as follows:

[0043] Step 1.1: Read the one-dimensional range image echo, and complete the calibration constant correction according to the external calibration information to display the ship target area signal.

[0044] Step 1.2: Perform signal transformation on the ship target area signal, that is, describe the transform domain characteristics of the ship target through time-domain and frequency-domain transformation.

[0045] Step 2: Extract statistical features of ship targets. The specific steps are as follows:

[0046] Step 2.1: Construction of peak value and peak width characteristic statistics. The peak value refers to the local maximum point in the range direction. By comparing the amplitude of each range cell with its two left and right cells in turn, the maximum amplitude is found to be the peak value. The peak width is calculated by the difference between the start and end positions of the peak.

[0047] Step 2.2: Construct the mean peak width of the one-dimensional range image of the ship's target region from the ship's echo sequence. shd ) and peak width variance (Var shd ).

[0048]

[0049]

[0050] Where x i denoted as , where is the crest width and N is the number of crests.

[0051] Step 2.3: Constructing Range Image Fluctuation Features. Differences in the distribution of scattering centers will cause varying degrees of fluctuation in the range cell echoes. Let the range image in the m-th azimuth domain of the target be {x}. cml |l=1,2,…,L}, the corresponding average distance image μ cm =[μ cm (1)…μ cm (N)]T, variance image in Let μ cm The support region is [n cm0 ,n cm The weighted vector of the distance image within the angular domain is obtained as follows: within the support region, the weight is taken as the reciprocal of the standard deviation of the corresponding distance cell; outside the support region, the weight is set to zero.

[0052]

[0053] The distance-weighted fluctuation feature is defined as:

[0054] v cmL =x cmL w cmL

[0055] The range image fluctuation feature obtained by the above formula includes both the absolute amplitude of the sample and reflects the fluctuation of the range cell echo as the target attitude changes.

[0056] Step 3: Extract the angular features of the target. The specific steps are as follows:

[0057] Step 3.1: Extract one-dimensional range signals according to angles, and perform amplitude normalization on the one-dimensional range image signals of the ship target. That is, amplitude normalization normalizes each one-dimensional range image using its maximum amplitude. As shown in the following formula:

[0058]

[0059] Step 3.2: Perform translation compensation based on the ship target's speed and time, ensuring that the target displayed in the one-dimensional range image remains centered as the angle changes.

[0060] Step 3.3: Use the range image matching method to estimate the target attitude angle. Divide the attitude range to be estimated into N regions according to the required attitude accuracy. Pre-store the target range image templates for each region. Match the real-time obtained range images with the templates. Obtain the attitude angle estimate by a certain discriminant function. Sort the attitude angles according to their size to obtain the azimuth attitude angle sorting features.

[0061] Step 3.4: Construct the characteristic quantities of ship target angle change according to the ship target angle change law.

[0062] Step 4: Extract the temporal features of the target. The specific steps are as follows:

[0063] Step 4.1: Extract the one-dimensional range image signal of the ship target according to time, and perform amplitude normalization on the one-dimensional range image signal of the ship target. That is, amplitude normalization normalizes each one-dimensional range image using its maximum amplitude. As shown in the following formula:

[0064]

[0065] Step 4.2: Perform translation compensation on the range image based on the time-averaged zero-phase representation method to achieve time alignment.

[0066] Step 4.3: Sort the targets according to their motion duration to construct target motion time features.

[0067] Step 4.4: Construct the characteristics of ship targets changing over time based on the time changes of the ship targets.

[0068] Furthermore, unless otherwise specified or required to occur in sequence, the order of the above steps is not limited to those listed above and can be varied or rearranged according to the desired design. For example, the order of steps 2, 3, and 4 in the above embodiments can be changed, and each step in steps 2, 3, and 4 can be performed sequentially or in parallel.

[0069] The embodiments of the present invention have now been described in detail with reference to the accompanying drawings. Based on the above description, those skilled in the art should have a clear understanding of the method for constructing one-dimensional range profile features of ship targets according to the present invention.

[0070] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure. Although this application has been disclosed in detail with reference to the accompanying drawings, it should be understood that these descriptions are merely exemplary and not intended to limit the application of this application. The scope of protection of this application is defined by the appended claims and may include various variations, modifications, and equivalent solutions made to the invention without departing from the scope and spirit of this application.

Claims

1. A method for constructing a one-dimensional range profile feature of a ship target, specifically including: Step 1: Analyze the one-dimensional range image echo data; Step 1.1: Read the one-dimensional range image echo, and complete the calibration constant correction according to the external calibration information to display the ship target area signal; Step 1.2: Perform signal transformation on the ship target area signal, that is, describe the transform domain characteristics of the ship target through time-domain and frequency-domain transformation; Step 2: Extract statistical features of ship targets; This includes one-dimensional distance image peak value, peak width, mean, variance, and distance fluctuation characteristics; Step 2.1: Construction of peak value and peak width characteristic statistics; Wherein: the peak value refers to the local maximum point in the range direction. The amplitude of each range unit in the range direction is compared with the two units to its left and right. The maximum amplitude is the peak value. The peak width is calculated by the difference between the start and end positions of the peak. Step 2.2: Construct the mean value of the peak width of the one-dimensional range image of the ship's target region from the ship echo sequence. shd and peak width variance Var shd ; ； ； in The width of the wave crest. The number of peaks; Step 2.3: Construct distance image undulation features; Among them: the difference in the distribution of scattering centers will cause the range cell echo to fluctuate to varying degrees; let the range image in the m-th azimuth domain of the target be . The corresponding average distance image T variance image T ,in 2 ;set up The support area is The weighted vector of the distance image within the angular domain is obtained as follows: within the support region, the weight is taken as the reciprocal of the standard deviation of the corresponding distance cell; outside the support region, the weight is set to zero. ； The distance-weighted fluctuation feature is defined as: ； The range image fluctuation feature obtained by the above formula includes both the absolute amplitude of the sample and reflects the fluctuation of the range cell echo as the target attitude changes; Step 3: Extract the angular features of the target and construct the angular change feature quantity of the ship target, including amplitude normalization processing, translation compensation, azimuth attitude angle sorting, and angular change features; Step 4: Extract the target's temporal features, including amplitude normalization, translation compensation and time alignment, target motion time sorting, and time change features.

2. The method for constructing one-dimensional range profile features of ship targets according to claim 1, characterized in that: In step 3: Step 3.1: Extract one-dimensional range signals according to angles, and normalize the amplitude of the one-dimensional range image signals of the ship target. That is, the amplitude normalization normalizes each one-dimensional range image using its maximum amplitude. As shown in the following formula: ； Step 3.2: Perform translation compensation based on the ship target's speed and time, ensuring that the target displayed in the one-dimensional range image remains centered as the angle changes; Step 3.3: Use the range image matching method to estimate the target attitude angle. Divide the attitude range to be estimated into M regions according to the required attitude accuracy. Pre-store the target range image templates for each region. Match the real-time obtained range images with the templates. Obtain the attitude angle estimate according to a certain discriminant function. Sort the attitude angles according to their size to obtain the azimuth attitude angle sorting features. Step 3.4: Construct the characteristic quantities of ship target angle change according to the ship target angle change law.

3. The method for constructing one-dimensional range profile features of ship targets according to claim 1, characterized in that: In step 4: Step 4.1: Extract the one-dimensional range image signal of the ship target according to time, and perform amplitude normalization on the one-dimensional range image signal of the ship target. That is, the amplitude normalization normalizes each one-dimensional range image using its maximum amplitude. As shown in the following formula: ； Step 4.2: Perform translation compensation on the range image based on the time-averaged zero-phase representation method to achieve time alignment; Step 4.3: Sort the targets according to their motion duration to construct target motion time features; Step 4.4: Construct the characteristics of ship targets changing over time based on the time changes of the ship targets.

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