Low, slow and small target locking and identifying method based on second type superlattice infrared detector

Abstract

The present application relates to the technical field of target locking identification, and particularly relates to a low, slow and small target locking identification method based on a two-class superlattice infrared detector. After a suspected target in a space domain is acquired, the suspected target is detected by using an infrared detector to acquire an infrared frame sequence of the suspected target in each detection period of a detection process; then, a radiation change frequency of the suspected target in each detection period is analyzed and acquired; further, the radiation change frequency and the position change of the suspected target are analyzed to acquire a bird confidence parameter, and then whether the suspected target is a low, slow and small target is judged and locked. After the suspected target is preliminarily identified, infrared detection is performed, then based on the infrared radiation and the position change characteristics of the suspected target in the infrared detection process, the possibility of the suspected target being a bird is evaluated, and finally whether the suspected target is a low, slow and small target is accurately determined, the misjudgment rate is reduced, and the locking identification effect on the low, slow and small target is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of target locking identification, and particularly relates to a low, slow and small target locking identification method based on a two-type superlattice infrared detector. BACKGROUND

[0002] The two-type superlattice infrared detector is an infrared detector based on two-type superlattice materials, and has high-sensitivity infrared radiation detection capability; the low, slow and small target usually refers to a low-altitude, low-speed, weak-signal and small-size artificial flight target, such as a drone, a spacecraft and the like, and in the air defense field, the low, slow and small artificial flight target will pose a threat to military air defense and national security, so it is crucial to accurately lock and identify the target.

[0003] Since the low, slow and small target can generate thermal radiation, in some air defense fields, the target is usually preliminarily detected and warned at a long distance by a radar, and then identified and locked by the two-type superlattice infrared detector. However, in the air defense field, there may also be bird flight targets, and the birds also generate thermal radiation, and in the flight process, the birds may also be mislocked and identified by the two-type superlattice infrared detector, thereby reducing the locking and identification effect of the low, slow and small target. SUMMARY

[0004] In order to solve the technical problem of poor locking and identification effect of the low, slow and small target, the purpose of the present application is to provide a low, slow and small target locking identification method based on a two-type superlattice infrared detector, and the technical solution is as follows:

[0005] The low, slow and small target locking identification method based on the two-type superlattice infrared detector comprises the following steps:

[0006] After a suspected target in a space domain is acquired, the suspected target is detected by using an infrared detector, and the pose of the infrared detector is unchanged in the detection process; in each detection period of the detection process, an infrared frame sequence of the suspected target is acquired, and the lengths of all detection periods are the same;

[0007] According to the infrared radiation change of the suspected target in each infrared frame sequence, a radiation change frequency of the suspected target in each detection period is acquired; according to the difference between the radiation change frequencies of the suspected target between all adjacent detection periods and the position difference between the infrared frame sequences corresponding to all adjacent detection periods, a bird confidence parameter is acquired;

[0008] Whether the suspected target is a low, slow and small target is judged according to the bird confidence parameter, and the suspected target is locked and observed.

[0009] Further, the method for acquiring the radiation change frequency comprises the following steps:

[0010] In each frame of each infrared frame sequence, the radiation intensity of the suspected target is obtained according to the infrared radiation values of all pixel points in the local range corresponding to the suspected target;

[0011] According to the change of the radiation intensity of the suspected target in each infrared frame sequence, the radiation change period value of the suspected target in the corresponding detection period is obtained, and the reciprocal of the radiation change period value is taken as the radiation change frequency in the corresponding detection period.

[0012] Further, the method for obtaining the radiation change period value comprises:

[0013] In each detection period, different period values are set, any period value is taken as a target period value, the corresponding infrared frame sequence is divided into different sub-sequences of equal length by using the target period value, the irregular change parameter under the target period value is obtained according to the change difference of the radiation intensity of the suspected target between different sub-sequences, and the period value corresponding to the smallest irregular change parameter in all period values is taken as the radiation change period value.

[0014] Further, the method for setting the period value comprises:

[0015] In each detection period, half of the total number of frames in the infrared frame sequence is taken as the right end point of the interval of the period value, a constant 2 is taken as the left end point of the interval of the period value, and all integers in the interval of the period value are taken as the period value.

[0016] Further, the method for obtaining the irregular change parameter comprises:

[0017] In each sub-sequence, the sum of the radiation intensity of the suspected target in all frames is taken as a radiation reference value, and the variance of the radiation reference values of all sub-sequences is taken as the irregular change parameter.

[0018] Further, the method for obtaining the bird confidence parameter comprises:

[0019] According to the radiation change frequency of the suspected target in each detection period and the change amount of the radiation change frequency relative to the radiation change frequency of the adjacent previous detection period, the wing beating parameter of the suspected target in each detection period is obtained.

[0020] According to the geometric center coordinates of the suspected target in all frames of the infrared frame sequence, the position coordinates of the suspected target in each detection period are obtained, and according to the vertical coordinate change amount of the position coordinates of the suspected target in each detection period relative to the position coordinates of the adjacent previous detection period, the takeoff parameter of the suspected target in each detection period is obtained.

[0021] According to the same sign property of the wing-flapping parameter and the ascending parameter, a bird confidence sub-parameter of the suspected target in each detection period is obtained; and the bird confidence sub-parameters of the suspected target in all detection periods are integrated to obtain a bird confidence parameter of the suspected target.

[0022] Further, the method for obtaining the bird confidence sub-parameter comprises:

[0023] The wing-flapping parameter is taken as a numerator, the ascending parameter is taken as a denominator, and a positive correlation mapping of a fractional ratio is taken as the bird confidence sub-parameter; when the ascending parameter is equal to 0, the bird confidence sub-parameter is 0.

[0024] Further, the method for screening the low, slow and small target comprises:

[0025] The bird confidence parameter is normalized, and when a normalized value is greater than a preset threshold value, the corresponding suspected target is determined to be a bird, otherwise, the corresponding suspected target is determined to be a low, slow and small target.

[0026] Further, the method for obtaining the suspected target comprises:

[0027] Radar echo signals in a space domain are obtained by using a radar, and a Doppler frequency shift of the radar echo signals is obtained; when the Doppler frequency shift is greater than a preset frequency shift threshold value, it is determined that a suspected target appears in a direction of the radar echo signals.

[0028] Further, a length of the detection period is 1 second.

[0029] The present application has the following beneficial effects:

[0030] After acquiring the suspected target in the airspace, the suspected target is detected by the infrared detector, and then in each detection period of the detection process, the infrared frame sequence of the suspected target is acquired, so as to provide a data analysis basis for subsequent analysis of the bird confidence parameter of the suspected target; then according to the infrared radiation change of the suspected target in each infrared frame sequence, the radiation change frequency of the suspected target in each detection period is acquired, to help evaluate whether the suspected target has the wing beating feature of the bird; further, according to the difference of the radiation change frequency of the suspected target between all adjacent detection periods and the position difference between the infrared frame sequences corresponding to all adjacent detection periods, whether the suspected target has the feature of accelerated wing beating frequency when rising is analyzed, so as to evaluate the bird confidence parameter; finally, whether the suspected target is a low, slow and small target is judged according to the bird confidence parameter and locked for observation, so as to reduce the possibility of interference and misjudgment caused by the bird. The present application preliminarily identifies the suspected target, then continuously monitors the suspected target by the infrared detector, evaluates the possibility of the suspected target being a bird based on the infrared radiation change feature of the suspected target in the detection process, finally accurately determines whether the suspected target is a low, slow and small target, so as to reduce the misjudgment rate and improve the locking and identification effect of the low, slow and small target. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, and the advantages thereof, below, a brief introduction will be given to the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0032] Figure 1 A flow chart of a low, slow and small target locking and identification method based on a two-type superlattice infrared detector provided by an embodiment of the present application;

[0033] Figure 2 A flow chart of a radiation change frequency acquisition method provided by an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to further explain the technical means and effects taken by the present application to achieve the predetermined invention purpose, below, the specific implementation, structure, features and effects of a low, slow and small target locking and identification method based on a two-type superlattice infrared detector according to the present application are described in detail in combination with the drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0036] The specific scheme of the low, slow and small target locking and identifying method based on the two-class superlattice infrared detector is specifically explained below in combination with the drawings.

[0037] Please refer to Figure 1 which shows a flow chart of a low, slow and small target locking and identifying method based on a two-class superlattice infrared detector according to an embodiment of the present application, and specifically includes:

[0038] In step S1, after a suspected target in the airspace is acquired, the suspected target is detected by using the infrared detector, and the pose of the infrared detector is unchanged during the detection process; in each detection period of the detection process, an infrared frame sequence of the suspected target is acquired, and the lengths of all detection periods are the same.

[0039] It should be noted that the implementation scenario of the present application is to first capture a suspected target in the airspace, and then track and detect the suspected target by using the two-class superlattice infrared detector, and further analyze and evaluate the possibility of the suspected target being a bird, so as to accurately identify a low, slow and small target.

[0040] It should be noted that the implementation scenario of the present application is to first capture a suspected target in the airspace, and then track and detect the suspected target by using the two-class superlattice infrared detector, and further analyze and evaluate the possibility of the suspected target being a bird, so as to accurately identify a low, slow and small target.

[0041] Based on this, in an embodiment of the present application, a detection radar such as a millimeter wave radar is first set at an airspace monitoring point, and the rotation speed of the radar is set to 1 time per second, that is, the airspace monitoring frequency of the detection radar is also 1 time per second; during the rotation of the radar, the radar transmitter will emit electromagnetic waves in each direction within the 360° range of the monitored airspace in each second, and when a suspected target is monitored, a return wave will be reflected back, so that a suspected target in the airspace is acquired.

[0042] Preferably, in an embodiment of the present application, considering that a low, slow and small target is usually moving, if the airspace object has relative motion with respect to the radar, that is, the airspace object is moving, then the frequency of the electromagnetic wave signal reflected back by the airspace object received by the radar, that is, the radar return signal, will change, and this change in frequency is called Doppler shift; therefore, whether a low, slow and small suspected target exists in the airspace can be determined based on the Doppler shift, and the acquisition method of the suspected target includes:

[0043] The radar echo signal in the space domain is acquired by using the radar, and the Doppler shift of the radar echo signal is acquired, and when the Doppler shift is greater than a preset frequency shift threshold, it is determined that a suspected target appears in the echo direction of the radar echo signal.

[0044] As an example, the radar echo signal is preprocessed, such as amplification and filtering, and the Doppler shift thereof is further acquired; the preset frequency shift threshold is set to 50 Hz, which can also be customized by the implementer; when the Doppler shift is greater than 50 Hz, it is considered that the space domain object in the echo direction of the radar echo signal has a motion characteristic, which is a low, slow and small suspected target; the implementer can further determine the position of the suspected target according to the radar echo signal in order to track and detect the subsequent second superlattice infrared detector.

[0045] It should be noted that the preprocessing of the radar echo signal, the acquisition of the Doppler shift, and the determination of the position of the suspected target according to the radar echo signal are all well-known prior art to those skilled in the art and will not be described in detail.

[0046] In an embodiment of the present application, a second superlattice infrared detector is arranged at a space monitoring point in synchronization, and when a suspected target in the space domain is captured, the second superlattice infrared detector starts to work; then the pose of the second superlattice infrared detector is adjusted according to the position of the suspected target, so that the center of the infrared image coincides with the geometric center of the suspected target; the suspected target is locked and continuously detected by using the second superlattice infrared detector, and the detection process is not less than 5s, and the pose of the infrared detector remains unchanged during the detection process; wherein the suspected target may move during the detection process, and the image center of the subsequent infrared frame image may no longer coincide with the geometric center of the suspected target.

[0047] Then the detection process is divided into a plurality of equal-length detection periods, for example, the length of the detection period is set to 1 second, and all the detection periods in the detection process are acquired; further, the detection frequency of the second superlattice infrared detector is set to 30 Hz, that is, 30 infrared frame images are acquired in each detection period, and then the frame images are sorted according to the acquisition order to construct an infrared frame image sequence.

[0048] It should be noted that adjusting the pose of the second superlattice infrared detector according to the position of the suspected target is well-known prior art to those skilled in the art and will not be described in detail; in other embodiments, the implementer can also define the length of the detection period and the detection frequency.

[0049] It should be noted that the layout and application of the detection radar and the second type of superlattice infrared detector in the airspace monitoring point are known technologies, and the implementer can adjust the layout scheme according to the actual situation; multiple suspected targets may exist in the airspace at the same time, and multiple second type of superlattice infrared detectors can be arranged in combination with the detection angle range of the second type of superlattice infrared detector to ensure that the complete airspace can be covered, and then multiple suspected targets can be tracked at the same time; wherein, one second type of superlattice infrared detector can also observe multiple suspected targets in the angle range.

[0050] It should be noted that the lock identification method for whether each suspected target is a low, slow and small target is consistent, and only any suspected target is taken as an example for analysis and description here.

[0051] Step S2, according to the infrared radiation change of the suspected target in each infrared frame sequence, the radiation change frequency of the suspected target in each detection period is obtained; according to the difference between the radiation change frequencies of the suspected target in all adjacent detection periods, and the position difference between the infrared frame sequences corresponding to all adjacent detection periods, the bird confidence parameter is obtained.

[0052] Considering that the flight targets with artificial properties in the airspace usually present infrared radiation characteristics, monitoring the infrared radiation of the suspected target can help identify the low, slow and small target; and considering that birds also present infrared radiation characteristics when flying in the airspace, birds need to flap their wings to maintain flight, and the infrared radiation of birds will change regularly with the flapping of the wings, while the infrared radiation of artificial flight targets is relatively stable;

[0053] Therefore, the embodiment of the present application first analyzes the radiation change frequency of the suspected target in each detection period according to the infrared radiation change of the suspected target in each infrared frame sequence, and then evaluates the bird confidence parameter based on the distinguishing characteristics that the infrared radiation change of the bird is relatively low compared with the infrared radiation change of the low, slow and small target.

[0054] Preferably, in an embodiment of the present application, the method for obtaining the radiation change frequency comprises:

[0055] Please refer to Figure 2 which shows a flow chart of a method for obtaining a radiation change frequency provided by an embodiment of the present application, and specifically comprises:

[0056] Step S201, in each frame of each infrared frame sequence, the radiation intensity of the suspected target is obtained according to the infrared radiation values of all pixel points in the local range corresponding to the suspected target.

[0057] In order to facilitate subsequent analysis of the infrared radiation intensity change of the suspected target, the embodiment of the present application first obtains the radiation intensity of the suspected target in each frame of the infrared frame sequence corresponding to each detection period.

[0058] In an embodiment of the present application, firstly, the region corresponding to the suspected target in each infrared frame sequence needs to be obtained; the implementer can obtain the pixel point corresponding to the suspected target in each frame based on the threshold judgment method; the threshold is set as the mean value or mode of all pixel points in the frame, when the pixel value is greater than the threshold, it is determined that the corresponding pixel point is the pixel point corresponding to the suspected target, and the connected domain of all suspected target corresponding pixel points is the region corresponding to the suspected target.

[0059] In other embodiments, the implementer can also manually label the suspected target in the frame, and then construct a training set to train the labeling model of the suspected target, and then input the frame to obtain the suspected target in the frame; other methods such as threshold segmentation or first obtaining the suspected target in the first frame, and then using the optical flow method to obtain the suspected target in all frames can also be used; all of them are prior art and will not be described in detail.

[0060] After obtaining the suspected target in each frame, the radiation intensity of the suspected target can be further obtained.

[0061] As an example, the mean value of the pixel value, i.e. the infrared radiation value, of all pixel points of the suspected target in the region corresponding to the suspected target in each frame is taken as the radiation intensity of the suspected target in the frame; in other examples, the implementer can also expand two unit pixel points from the outermost layer of the suspected target corresponding region, i.e. expand two circles from the outermost layer, to obtain the target expansion region, and further take the mean value of the pixel value of all pixel points in the target expansion region as the radiation intensity of the suspected target in the corresponding frame.

[0062] In step S202, according to the change of the radiation intensity of the suspected target in each infrared frame sequence, the radiation change period value of the suspected target in the corresponding detection period is obtained, and the reciprocal of the radiation change period value is taken as the radiation change frequency in the corresponding detection period.

[0063] In order to facilitate subsequent evaluation of whether it has the characteristics of bird wing vibration to determine the bird confidence coefficient, the present embodiment analyzes the infrared radiation change rule of the suspected target in each detection period to obtain the radiation change period value of the suspected target in the corresponding detection period. The larger the radiation change period value is, the lower the radiation change frequency is, and then the possibility of birds can be evaluated in combination with the frequency characteristics of bird wing vibration.

[0064] In a preferred embodiment of the present application, if the radiation intensity of the suspected target changes periodically, the radiation intensity in different periods will have similarity; and based on the preset period value, the period sub-section is divided, the irregular change of the radiation intensity of the suspected target in different period sub-sections is evaluated, and then the confidence degree of the corresponding preset period can be evaluated; then the radiation change period value is analyzed and evaluated by iterating different preset period values; based on this, the method for obtaining the radiation change period value comprises:

[0065] Different period values are set in each detection period, any period value is a target period value, the corresponding infrared frame sequence is divided into different sub-sequences of equal length by using the target period value, the irregular change parameter under the target period value is obtained according to the change difference of the radiation intensity of the suspected target between different sub-sequences, and the period value corresponding to the smallest irregular change parameter is taken as the radiation change period value in all period values.

[0066] In a preferred embodiment of the present application, considering that the length of the sub-sequence should be at least greater than 1 and not too large to avoid invalid analysis, the setting method of the period value comprises:

[0067] In each detection period, half of the total number of frame sequences in the infrared frame sequence is taken as the right end point of the interval of the period value, the constant 2 is taken as the left end point of the interval of the period value, and all integers in the interval of the period value are taken as the period value; that is, from 2 to half of the total number of frames, the interval of the period value is a double closed interval; the implementer can also set the period value set for iterative analysis.

[0068] In a preferred embodiment of the present application, considering that there are multiple frames in each sub-sequence, in order to facilitate the analysis of the radiation intensity difference of the suspected target in different sub-sequences, first, the radiation intensity of the suspected target in all frames in each sub-sequence is integrated to determine a radiation reference value; and considering that the variance can measure the dispersion of the radiation reference values between different sub-sequences, and then help to evaluate the irregular change of the radiation intensity of the suspected target in the detection period; based on this, the irregular change parameter acquisition method comprises:

[0069] In each sub-sequence, the sum of the radiation intensities of the suspected targets in all frames is taken as the radiation reference value; and the variance of the radiation reference values of all sub-sequences is taken as the irregular change parameter.

[0070] In other embodiments, the implementer can also construct the corresponding radiation intensity sequence according to the frame sequence order of the suspected target in each frame of each sub-sequence; then compare the difference such as the DTW distance between the radiation intensity sequences of two sub-sequences, and then take the sum value of all differences obtained by comparison as the irregular change parameter; it is prior art and will not be described in detail.

[0071] Considering that birds gradually increase the frequency of wing flapping to maintain buoyancy when flying in the air, the radiation frequency of birds corresponding to suspected targets gradually increases between adjacent detection periods during the detection process; while during descent, birds usually glide to conserve energy, reducing or ceasing wing flapping frequency, so the radiation frequency of birds corresponding to suspected targets should gradually decrease between adjacent detection periods; and the position of suspected targets in the frame changes during ascent and descent.

[0072] Based on this, embodiments of the present invention obtain bird confidence parameters according to the differences in radiation change frequency of the suspected target between all adjacent detection periods and the positional differences between the corresponding infrared frame sequences in all adjacent detection periods; the bird confidence parameters reflect the possibility that the suspected target has bird characteristics, preparing for the subsequent determination that the suspected target is a low, slow and small target.

[0073] Preferably, in one embodiment of the present invention, considering that the rate of change of radiation of the suspected target during the detection period shows an increasing trend compared to the previous detection period, it indicates that the target may exhibit a tendency to rise due to an increase in wingbeat frequency; and the change in the ordinate of the geometric center of the suspected target in the infrared frame can help assess whether the suspected target has risen; if both the wingbeat frequency and the ordinate increase, the likelihood of it being a bird is greater; based on this, the method for obtaining the bird confidence parameter includes:

[0074] Based on the radiation change frequency of the suspected target in each detection period and the change in radiation change frequency relative to the adjacent previous detection period, the flapping parameters of the suspected target in each detection period are obtained.

[0075] Based on the geometric center coordinates of the suspected target in all frames of the infrared frame sequence, the position coordinates of the suspected target in each detection period are obtained; based on the position coordinates of the suspected target in each detection period and the change in the ordinate relative to the position coordinates of the previous adjacent detection period, the launch parameters of the suspected target in each detection period are obtained.

[0076] Based on the same sign of the wingbeat parameters and ascent parameters, bird confidence sub-parameters for suspected targets are obtained for each detection period; by combining the bird confidence sub-parameters for suspected targets across all detection periods, bird confidence parameters for suspected targets are obtained.

[0077] In a preferred embodiment of the present invention, the method for obtaining the bird confidence sub-parameter includes:

[0078] Using the wingbeat parameter as the numerator and the ascent parameter as the denominator, the ratio of the fractions is positively correlated and then used as the bird confidence sub-parameter; when the ascent parameter is equal to 0, the bird confidence sub-parameter is set to 0.

[0079] As an example, firstly through The change in radiation frequency of the suspected target is calculated using the following method, and this value is used as the wing flapping parameter of the suspected target in the (i+1)th detection period; where i is the sequence number of the detection period, w i w represents the frequency of radiation variation of the suspected target during the i-th detection period. i+1 The radiation variation frequency of the suspected target during the (i+1)th detection period is given. Similarly, the ascent parameters of the suspected target during the (i+1)th detection period can be obtained. Then, the ratio of the wing flapping parameters to the ascent parameters of the suspected target during each detection period is used as x in the power function exp(x) with the natural constant e as the base, and the range is adjusted accordingly. When the numerator and denominator have opposite signs, the smaller the mapping result, the smaller the bird confidence sub-parameter. Finally, the bird confidence sub-parameters of all detection periods are summed and linearly normalized to obtain the bird confidence parameters.

[0080] It should be noted that the wing flapping parameters and ascent parameters may take negative values. When they are negative, it indicates that the suspected target's wing flapping frequency has decreased and its position has dropped.

[0081] In other examples, the implementer may also record the bird confidence sub-parameter as 1 when the wing flapping parameter and the take-off parameter have the same sign (i.e., both are positive or negative) during each detection period, and 0 otherwise; finally, the bird confidence sub-parameters in all detection periods during the detection process are accumulated and normalized to obtain the bird confidence parameter.

[0082] Step S3: Determine whether the suspected target is a low, slow, and small target based on the bird confidence parameters and lock it for observation.

[0083] After obtaining the bird confidence parameters of a suspected target during the detection process, it can be further determined whether it is a bird, which facilitates subsequent identification of low, slow, and small targets to determine whether they pose a potential threat.

[0084] Preferably, in one embodiment of the present invention, the method for screening low-speed, small targets includes:

[0085] The bird confidence parameter is normalized. When the normalized value is greater than a preset threshold, the corresponding suspected target is determined to be a bird; otherwise, it is a low, slow, and small target. The preset threshold is set to 0.65, but the implementer can also customize it.

[0086] In one embodiment of the present application, when it is determined that the suspected target is a low, slow and small target, the low, slow and small target is locked and then continuously observed based on radar or a second-type superlattice infrared detector, and the flight trajectory of the low, slow and small target in the airspace is recorded; then a large number of historical flight trajectories of the low, slow and small targets are obtained, a spatial trajectory prediction model is constructed and trained, and the basic architecture of the model is an LSTM model; the spatial coordinates sequence corresponding to the flight trajectory of the current low, slow and small target is input into the trained spatial model, and the predicted flight trajectory is output; the implementer can further obtain a large number of historical flight trajectories of the low, slow and small targets with manually annotated flight purposes or threat levels, train a threat assessment model, input the flight trajectory of the current low, slow and small target into the trained threat assessment model, and output the threat level of the low, slow and small target, thereby warning whether to strike or disperse.

[0087] It should be noted that the training and application of the above model are prior art and will not be described again.

[0088] In summary, after obtaining the suspected target in the airspace, the suspected target is detected by using the infrared detector, and the pose of the infrared detector is unchanged during the detection process; in each detection period of the detection process, the infrared frame sequence of the suspected target is obtained, and the lengths of all detection periods are the same; according to the infrared radiation change of the suspected target in each infrared frame sequence, the radiation change frequency of the suspected target in each detection period is obtained; according to the difference between the radiation change frequencies of the suspected target in all adjacent detection periods and the position difference between the infrared frame sequences corresponding to all adjacent detection periods, the bird confidence parameter is obtained; and whether the suspected target is a low, slow and small target is determined according to the bird confidence parameter and the suspected target is locked and observed. After the suspected target is preliminarily identified, the suspected target is continuously detected by using the infrared detector, the possibility of the suspected target being a bird is evaluated based on the infrared radiation change characteristics of the suspected target during the detection process, and whether the suspected target is a low, slow and small target is finally accurately determined, thereby reducing the misjudgment rate and improving the locking and identification effect of the low, slow and small target.

[0089] It should be noted that the above-mentioned embodiments of the present application are only for description and do not represent the advantages and disadvantages of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are also possible or can be advantageous.

[0090] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other, and each embodiment mainly describes the differences from other embodiments.

Claims

1. A low-slow-small target locking and identifying method based on a type II superlattice infrared detector, characterized in that, The method comprises: After acquiring the suspected target in the airspace, the suspected target is detected by using the infrared detector, and the pose of the infrared detector is unchanged during the detection process; in each detection period of the detection process, an infrared frame sequence of the suspected target is acquired, and the lengths of all the detection periods are the same; According to the infrared radiation change of the suspected target in each infrared frame sequence, the radiation change frequency of the suspected target in each detection period is acquired; according to the difference between the radiation change frequencies of the suspected target in all adjacent detection periods and the position difference between the corresponding infrared frame sequences of all adjacent detection periods, the bird confidence parameter is acquired; According to the bird confidence parameter, it is judged whether the suspected target is a low, slow and small target and is locked for observation; The method for acquiring the bird confidence parameter comprises: According to the radiation change frequency of the suspected target in each detection period and the change amount of the radiation change frequency relative to the radiation change frequency of the adjacent previous detection period, the wing flapping parameter of the suspected target in each detection period is acquired; According to the geometric center coordinates of the suspected target in all frame sequences of the infrared frame sequence, the position coordinates of the suspected target in each detection period are acquired; according to the change amount of the vertical coordinates of the position coordinates of the suspected target in each detection period relative to the position coordinates of the adjacent previous detection period, the lift-off parameter of the suspected target in each detection period is acquired; According to the same sign of the values of the wing flapping parameter and the lift-off parameter, the bird confidence sub-parameter of the suspected target in each detection period is acquired; and the bird confidence parameters of the suspected target in all detection periods are integrated to acquire the bird confidence parameter of the suspected target.

2. The method according to claim 1, wherein the infrared detector is a Type-II superlattice infrared detector. The method for acquiring the radiation change frequency comprises: In each frame of each infrared frame sequence, the radiation intensity of the suspected target is acquired according to the infrared radiation values of all pixel points in the local range corresponding to the suspected target; According to the change of the radiation intensity of the suspected target in each infrared frame sequence, the radiation change period value of the suspected target in the corresponding detection period is acquired, and the reciprocal of the radiation change period value is taken as the radiation change frequency in the corresponding detection period.

3. The method according to claim 2, wherein the infrared detector is a Type-II superlattice infrared detector. The method for acquiring the radiation change period value comprises: In each detection period, different period values are set, any period value is taken as a target period value, the corresponding infrared frame sequence is divided into different subsequences with equal lengths by using the target period value, the irregular change parameter under the target period value is acquired according to the change difference of the radiation intensity of the suspected target between different subsequences, and the period value corresponding to the smallest irregular change parameter in all period values is taken as the radiation change period value.

4. The method according to claim 3, wherein the infrared detector is a Type-II superlattice infrared detector. The method for setting the period value comprises: In each detection period, half of the total number of frame sequences in the infrared frame sequence is taken as the right end point of the interval of the period value, a constant 2 is taken as the left end point of the interval of the period value, and all integers in the interval of the period value are taken as the period values.

5. The method according to claim 3, wherein the infrared detector is a Type-II superlattice infrared detector. The method for acquiring the irregular change parameter comprises: In each subsequence, the sum of the radiation intensities of the suspected target in all frame sequences is taken as a radiation reference value, and the variance of the radiation reference values of all subsequences is taken as the irregular change parameter.

6. The method according to claim 1, wherein the infrared detector is a Type-II superlattice infrared detector. The method for acquiring the bird confidence sub-parameter comprises: The wing vibration parameter is taken as a numerator, the lift-off parameter is taken as a denominator, and a positive correlation mapping of a fractional ratio is taken as a bird confidence parameter; when the lift-off parameter is equal to 0, the bird confidence parameter is 0.

7. The method according to claim 1, wherein the method is a low, slow and small target locking and identifying method based on the type-2 superlattice infrared detector. The low, slow and small target screening method comprises: The bird confidence parameter is normalized, and when a normalized value is greater than a preset threshold value, the corresponding suspected target is determined to be a bird, otherwise, the corresponding suspected target is determined to be a low, slow and small target.

8. The method according to claim 1, wherein the infrared detector is a Type-II superlattice infrared detector. The suspected target acquisition method comprises: A radar is used to acquire a radar echo signal in a space domain, and a Doppler frequency shift of the radar echo signal is acquired, and when the Doppler frequency shift is greater than a preset frequency shift threshold value, it is determined that a suspected target appears in a direction of the radar echo signal.

9. The method according to claim 1, wherein the method is a low, slow and small target locking and identifying method based on the type-2 superlattice infrared detector. The detection period is 1 second.

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