JP4791239B2 - Target speed measuring device, target speed measuring program, and target speed measuring method - Google Patents

Description

  The present invention relates to an apparatus for measuring the speed of a target from, for example, a SAR (Synthetic Aperture Radar) image.

Accurate knowledge of the moving component (velocity) of the moving target is important for obtaining a high-resolution ISAR (Inverse Synthetic Aperture Radar) image. 2. Description of the Related Art Conventionally, there is an isolated scattering point method ISAR process that tracks an object that exhibits strong radio wave scattering in the absence of a radio wave scatterer and reproduces an image of a target object.
JP-A-11-183606 JP 2003-130950 A

In the conventional isolated scattering point method ISAR processing, tracking is unstable and the target image is not clearly sharpened when there is a radio wave scatterer around or when the brightness of a moving (moving) target is weak. There is a problem.
Further, conventionally, there is a problem that the speed of the target cannot be obtained.

  An object of the present invention is to determine the speed of a target, for example. Another object is to correctly sharpen the image of the target.

The target velocity measuring apparatus according to the present invention is, for example, a target velocity measuring apparatus that measures the velocity of a target observed by a SAR.
A data input unit for inputting the range-compressed data obtained by performing range compression on the target data observed by the SAR and storing the data in the storage device;
A speed input unit that inputs a plurality of predicted speeds of the target and stores them in a storage device;
The distance information between the SAR-equipped machine and the target based on the movement information of the SAR-equipped machine and the predicted movement information of the predetermined target, and a plurality of predicted speeds of the plurality of predicted speeds input by the speed input unit. A reference function generation unit that generates a reference function of
An azimuth compression processing unit that generates azimuth-compressed data after the range compression and generates a plurality of post-azimuth-compressed data by a processing device based on each reference function of the plurality of reference functions generated by the reference function generation unit;
A definition calculation unit that calculates the definition of an image of a target indicated by each azimuth-compressed data of the plurality of azimuth-compressed data generated by the azimuth compression processing unit;
When the reference function used to generate the azimuth-compressed data having the highest definition image of the target calculated by the definition calculation unit is generated, the predicted speed used by the reference function generation unit is set as the target It is provided with the speed determination part which determines with a processing apparatus that it is the speed of an object.

The speed input unit is configured to change a coefficient for a polynomial of each degree in order from a polynomial having a low degree to a polynomial having a high degree from a polynomial of 0 degree to n order (n is an arbitrary natural number) representing a predicted speed. Enter the predicted speed,
The speed determination unit determines the speed of the target when represented by a polynomial of each degree in order from a polynomial having a low degree of polynomial to a polynomial having a high degree,
When the predicted speed represented by the nth order polynomial is input, the speed input unit represents the speed of the target for which the speed determination unit has determined the coefficients of the respective orders from the 0th order to the (n−1) th order ( n-1) A coefficient of each degree of a degree polynomial is used.

The speed input unit is represented by a range-direction predicted speed represented by a polynomial of 0th order to kth order (k is an arbitrary natural number) and a polynomial of 0th order to lth order (l is an arbitrary natural number). In order from the low-order polynomial to the high-order polynomial of each prediction speed with the prediction speed in the azimuth direction, input a plurality of prediction speeds by changing the coefficient for each order polynomial of each prediction speed,
The speed determination unit sequentially determines the speed of the target in the order of the polynomial in each order from the low-order polynomial to the high-order polynomial, from the speed in the range direction to the speed in the azimuth direction,
When the speed input unit inputs a predicted speed in the range direction represented by a k-th order polynomial, the speed input unit represents the speed in the range direction in which the speed determination unit determines each coefficient from the 0th order to the (k−1) th order. (K-1) When the predicted speed in the azimuth direction represented by the lth order polynomial is input as the coefficient of each order of the order polynomial, the speed determination unit determines each coefficient from the 0th order to the (l-1) th order. It is characterized in that it is a coefficient of each degree of the (l-1) degree polynomial that represents the determined speed in the azimuth direction.

  The reference function generation unit inputs each prediction speed of the plurality of prediction speeds input by the speed input unit to the reference function expression 5 obtained from Expression 4 representing the distance relationship information between the SAR-equipped machine and the target. A plurality of reference functions are generated.

Further, the target velocity measuring device further includes:
A correction amount is calculated based on Equation 6, and a range migration correction unit that performs range migration correction on the range-compressed data input by the data input unit based on the calculated correction amount,
The azimuth compression processing unit generates azimuth-compressed data by performing azimuth compression on the corrected data corrected by the range migration correction unit by the range migration correction unit.

Further, the target velocity measuring device further includes:
A synthetic aperture time information input unit for inputting a plurality of synthetic aperture time information having a start time of the synthetic aperture time and an end time of the synthetic aperture time by an input device,
The reference function generation unit includes each synthetic aperture time information of the plurality of synthetic aperture time information input by the synthetic aperture time information input unit, each predicted speed of the plurality of predicted rates input by the speed input unit, and the distance A plurality of reference functions are generated by the processing device based on the relationship information.

Further, the target velocity measuring device according to the present invention is, for example, a target velocity measuring device that measures the velocity of a target observed by the SAR.
A data input unit that inputs range-compressed data obtained by performing range compression on the data observed by the SAR and stores the data in a storage device;
A speed input unit that inputs a plurality of predicted speeds of the SAR-equipped machine and stores them in a storage device;
Each prediction of a plurality of predicted speeds of the SAR-equipped machine inputted by the speed input unit and the distance relation information between the SAR-equipped machine and the target based on the predicted movement information of the SAR-equipped machine and the movement information of the predetermined target. A reference function generator for generating a plurality of SAR speed measurement reference functions by the processing device and storing them in the storage device according to the speed;
Azimuth compression in which the range-compressed data is azimuth-compressed and a plurality of azimuth-compressed data is generated by a processor based on each SAR speed measurement reference function of the plurality of SAR speed measurement reference functions generated by the reference function generation unit A processing unit;
A target selection unit for selecting a target included in the range-compressed data input by the data input unit with an input device;
The processing device calculates the sharpness of the target image indicated by each post-azimuth compressed data of the plurality of post-azimuth compressed data generated by the azimuth compression processing unit and selected by the target selection unit. A definition calculation unit;
When the reference function used to generate the azimuth-compressed data having the highest definition of the target image calculated by the definition calculation unit is generated, the predicted speed used by the reference function generation unit is SAR. A speed determination unit for determining by the processing device that the speed of the mounted machine,
The speed input unit inputs a plurality of predicted speeds of the target,
The reference function generating unit is configured to determine a distance between the SAR-equipped machine and the target based on the movement information of the SAR-equipped machine based on the speed of the SAR-equipped machine determined by the speed determining unit and the predicted movement information of the predetermined target. A plurality of target speed measurement reference functions are generated from the relationship information and the predicted speeds of the target predicted speeds input by the speed input unit,
The azimuth compression processing unit azimuth-compresses the range-compressed data based on each target velocity measurement reference function of the plurality of target velocity measurement reference functions generated by the reference function generation unit, and performs a plurality of azimuth compressions. Generate data,
The definition calculation unit calculates the definition of the image of the target indicated by each azimuth-compressed data of the plurality of azimuth-compressed data generated by the azimuth compression processing unit,
The speed determination unit generates the reference function used to generate the azimuth-compressed data having the highest definition of the target image calculated by the definition calculation unit. It is characterized in that the used predicted speed is determined as the target speed.

The target speed measurement program according to the present invention is, for example, a target speed measurement program for measuring the speed of a target observed by the SAR.
A data input process for inputting the range-compressed data obtained by performing range compression on the target data observed by the SAR and storing the data in the storage device;
A speed input process for inputting a plurality of predicted speeds of the target and storing them in a storage device;
The distance information between the SAR-equipped machine and the target based on the movement information of the SAR-equipped machine and the predicted movement information of the predetermined target, and a plurality of predicted speeds of the plurality of predicted speeds input in the speed input process. A reference function generation process of generating a reference function of
Based on each reference function of the plurality of reference functions generated in the reference function generation processing, the azimuth compression processing for generating the azimuth compressed data after the range compression and generating a plurality of azimuth compressed data by the processing device,
A definition calculation process for calculating the definition of the image of the target indicated by each azimuth-compressed data of the plurality of azimuth-compressed data generated by the azimuth compression process;
When generating the reference function used to generate the azimuth-compressed data having the highest definition of the target image calculated in the definition calculation process, the target speed is the predicted speed used in the reference function generation process. It is characterized by causing a computer to execute a speed determination process for determining the speed of an object by a processing device.

The speed input process is performed by changing coefficients for polynomials of respective orders in order from a polynomial having a lower degree to a polynomial having a higher degree from a polynomial of 0th order to nth order (n is an arbitrary natural number) representing the predicted speed. Enter the predicted speed,
The speed determination process determines the speed of the target when represented by polynomials of respective orders in order from a polynomial having a lower polynomial order to a higher polynomial,
In the speed input process, when a predicted speed represented by an nth-order polynomial is input, the speed of the target for which the coefficient of each order from the 0th order to the (n−1) th order is determined by the speed determination process ( n-1) A coefficient of each degree of a degree polynomial is used.

The speed input process is represented by a range-direction predicted speed represented by a polynomial of 0th order to kth order (k is an arbitrary natural number) and a polynomial of 0th order to lth order (l is an arbitrary natural number). In order from the low-order polynomial to the high-order polynomial of each prediction speed with the prediction speed in the azimuth direction, input a plurality of prediction speeds by changing the coefficient for each order polynomial of each prediction speed,
The speed determination process sequentially determines the speed of the target in the order of the polynomial in each order from the low-order polynomial to the high-order polynomial, from the speed in the range direction to the speed in the azimuth direction,
In the speed input process, when the predicted speed in the range direction represented by the k-th order polynomial is input, the speed in the range direction in which the coefficients from the 0th order to the (k−1) th order are determined in the speed determination process is represented. (K-1) When the predicted speed in the azimuth direction represented by the l-order polynomial is input as the coefficient of each degree of the order polynomial, the coefficients from the 0th order to the (l-1) -th order are input in the speed determination process. It is characterized in that it is a coefficient of each degree of the (l-1) degree polynomial that represents the determined speed in the azimuth direction.

  In the reference function generation process, each predicted speed of the plurality of predicted speeds input in the speed input process is input to the reference function expression 5 obtained from Expression 4 representing the distance relationship information between the SAR-equipped machine and the target. A plurality of reference functions are generated.

The target speed measurement program further includes:
A correction amount is calculated based on Equation 6, and based on the calculated correction amount, the computer is caused to execute range migration correction processing for performing range migration correction on the range-compressed data input in the data input processing,
The azimuth compression process is characterized in that the corrected data subjected to the range migration correction in the range migration correction process is azimuth compressed to generate post-azimuth compressed data.

The target speed measurement program further includes:
Causing the computer to execute a synthetic aperture time information input process for inputting a plurality of synthetic aperture time information having a start time of the synthetic aperture time and an end time of the synthetic aperture time by an input device;
The reference function generation process includes the synthetic aperture time information of the plurality of synthetic aperture time information input in the synthetic aperture time information input process, the predicted speeds of the plurality of predicted speeds input in the speed input process, and the distance A plurality of reference functions are generated by the processing device based on the relationship information.

The target speed measurement program according to the present invention is, for example, a target speed measurement program for measuring the speed of a target observed by the SAR.
A data input process for inputting the range-compressed data obtained by performing range compression on the data observed by the SAR and storing the data in the storage device;
A speed input process for inputting a plurality of predicted speeds of the SAR-equipped machine and storing them in a storage device;
Prediction movement information of the SAR-equipped machine and information on the distance between the SAR-equipped machine and the target based on the movement information of the predetermined target, and each prediction of a plurality of predicted speeds of the SAR-equipped machine input in the speed input process A reference function generation process in which a plurality of SAR speed measurement reference functions are generated by a processing device according to speed and stored in a storage device;
Azimuth compression in which the range-compressed data is azimuth-compressed and a plurality of azimuth-compressed data is generated by the processing unit based on each SAR speed measurement reference function of the plurality of SAR speed measurement reference functions generated in the reference function generation processing. Processing,
A target selection process in which a target included in the data after range compression input in the data input process is selected by an input device;
A clear image of a target image indicated by each post-azimuth-compressed data of a plurality of post-azimuth-compressed data generated by the azimuth compression processing, which is calculated by the processing device by the processing device. Degree calculation processing,
When generating the reference function used to generate the azimuth-compressed data having the highest definition image of the target calculated in the definition calculation process, the predicted speed used in the reference function generation process is set to SAR. Causing the computer to execute speed determination processing that is determined by the processing device to be the speed of the mounted machine,
The speed input process inputs a plurality of predicted speeds of the target,
In the reference function generation process, the distance between the SAR-equipped machine and the target based on the movement information of the SAR-equipped machine based on the speed of the SAR-equipped machine determined in the speed determination process and the predicted movement information of the predetermined target. A plurality of target speed measurement reference functions are generated based on the relationship information and the predicted speeds of the target predicted speeds input in the speed input process,
In the azimuth compression processing, the range-compressed data is azimuth-compressed based on each target velocity measurement reference function of the plurality of target velocity measurement reference functions generated in the reference function generation processing, and a plurality of azimuth-compressed data Produces
The sharpness calculation process calculates the sharpness of the target image indicated by each azimuth-compressed data of the plurality of azimuth-compressed data generated by the azimuth compression process,
In the reference function generation process, the speed determination process is performed when the reference function used to generate the azimuth-compressed data having the highest definition of the target image calculated in the definition calculation process is generated. It is characterized in that the used predicted speed is determined as the target speed.

Moreover, the target velocity measuring method according to the present invention is, for example, a target velocity measuring method of a target velocity measuring apparatus that measures a velocity of a target observed by SAR.
A data input step in which the storage device inputs and stores the range-compressed data obtained by subjecting the target data observed by the SAR to range compression;
A speed input step in which the storage device inputs and stores a plurality of predicted speeds of the target; and
Each prediction of a plurality of predicted speeds input in the speed input step and distance information between the SAR mounted machine and the target based on the movement information of the SAR mounted machine and the predicted movement information of the predetermined target. A reference function generation step of generating and storing a plurality of reference functions by the processing device according to speed;
A processing unit, based on each reference function of the plurality of reference functions generated in the reference function generation step, azimuth compression the range-compressed data to generate a plurality of azimuth compressed data,
A processing device calculates a definition of a target image indicated by each azimuth-compressed data of the plurality of azimuth-compressed data generated in the azimuth compression step; and
Used in the reference function generation step when the processing device generates the reference function used to generate the azimuth-compressed data having the highest definition of the target image calculated in the definition calculation step. And a speed determination step for determining that the predicted speed is the speed of the target.

  According to the target speed measuring device, the target speed measuring program, and the target speed measuring method according to the present invention, it is possible to obtain the target speed with high accuracy by estimating the target speed from the image. Further, the speed of the target can be expressed by a high-order polynomial, and the coefficient of each order can be estimated from the image, so that the speed of the target can be obtained with higher accuracy.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, an example of a hardware configuration of the SAR-equipped machine speed measuring device 100 (image sharpening device) and the target speed measuring device 200 according to the embodiment will be described with reference to FIGS.

FIG. 1 is a diagram illustrating an example of the appearance of a SAR-equipped machine speed measuring device 100 and a target speed measuring device 200 according to an embodiment.
In FIG. 1, a SAR-equipped machine speed measuring device 100 and a target speed measuring device 200 include a CRT (Cathode Ray Tube) display device 901, a keyboard (K / B) 902, a mouse 903, a compact disk device (CDD) 905, a database. 908, a system unit 909, and a server 910, which are connected by a cable.
Further, the SAR-equipped machine speed measurement device 100 and the target speed measurement device 200 are connected to the Internet 940 via a local area network (LAN) 942 and a gateway 941.
Here, the CRT display device 901 is an example of the display device 986.

FIG. 2 is a diagram illustrating an example of a hardware configuration of the SAR-equipped machine speed measuring device 100 and the target speed measuring device 200 in the embodiment.
In FIG. 2, the SAR-equipped machine speed measurement device 100 and the target speed measurement device 200 include a CPU (Central Processing Unit) 911 that executes a program. The CPU 911 is connected to a ROM 913, a RAM 914, a communication board 915, a CRT display device 901, a K / B 902, a mouse 903, an FDD (Flexible Disk) 904, a CDD 905, and a magnetic disk device 920 via a bus 912. The CPU is an example of a processing device.
The RAM 914 is an example of a volatile memory. The ROM 913 and the magnetic disk device 920 are examples of a nonvolatile memory. These are examples of the storage device 984.
The communication board 915 is connected to the LAN 942 or the like.
The K / B 902, the mouse 903, and the like are examples of the input device 982.
The CPU 911 is an example of a processing device.

Here, the communication board 915 is not limited to the LAN 942 but may be directly connected to the Internet 940 or a WAN (Wide Area Network) such as ISDN. When directly connected to the Internet 940 or a WAN such as ISDN, the SAR-equipped machine speed measuring device 100 and the target speed measuring device 200 are connected to the Internet 940 or a WAN such as ISDN, and the gateway 941 is unnecessary. Become.
The magnetic disk device 920 stores an operating system (OS) 921, a window system 922, a program group 923, and a file group 924. The program group 923 is executed by the CPU 911, the OS 921, and the window system 922.

The program group 923 stores programs that execute functions described as “˜units” in the description of the embodiments described below. The program is read and executed by the CPU 911.
In the file group 924, what is described as “to determination” in the description of the embodiment described below is stored as “to file”.
Also, the arrows in the flowcharts described in the following description of the embodiments mainly indicate data input / output, and the data for the data input / output is the magnetic disk device 920, FD, optical disk, CD, MD. (Mini disc), DVD (Digital Versatile Disk) and other recording media. Alternatively, it is transmitted through a signal line or other transmission medium.

  In addition, what is described as “unit” in the description of the embodiment described below may be realized by firmware stored in the ROM 913. Alternatively, it may be implemented by software alone, hardware alone, a combination of software and hardware, or a combination of firmware.

  In addition, a program that implements the embodiment described below may be stored using a recording device using another recording medium such as the magnetic disk device 920, FD, optical disk, CD, MD, DVD, or the like.

Embodiment 1 FIG.
Next, the first embodiment will be described. In the first embodiment, a SAR-equipped machine speed measuring device 100 that measures the speed of a SAR-equipped machine will be described.

First, the relative positional relationship between the SAR mounting machine and the target will be described with reference to FIGS. Here, it is assumed that the target is stationary on the ground that rotates during the observation time (for example, several seconds). FIG. 3 is a diagram showing a relative relationship (distance) after t seconds between the SAR-equipped machine and the target. FIG. 4 is a diagram illustrating movement of the target in FIG. 3 due to rotation. That is, the target itself does not move, but the target moves by rotation when viewed from the SAR-equipped machine.
Here, Equation 7 shows the distance vector between the SAR-equipped device and the target after t seconds based on the movement of the SAR-equipped device, and Equation 8 shows the velocity vector of the target due to rotation. From Equation 7 and Equation 8, Equation 9 is obtained as the relative motion (distance) between the SAR-equipped machine and the target after t seconds.

Assuming that the velocity component of the SAR-equipped machine is constant, the distance between the SAR-equipped machine and the target is given by Equation 10 in consideration of the movement of the observation point in the range direction and azimuth direction due to the earth rotation.

In general, the azimuth direction speed component of rotation and the speed component of the SAR-equipped machine can be described together. Here, _{"- V P = (v aE -V} P_pre) " a, _{V P} represents the relative velocity of the target.

From Equation 11, the azimuth compression reference function is calculated as follows.

Here, the speed of Expression 11 is expressed as a polynomial as follows.

By specifying the coefficient of each degree of the polynomial representing this speed, the speed of the SAR-equipped machine is specified.

Next, an outline of a method by which the SAR-equipped machine speed measuring device 100 specifies the speed of the SAR-equipped machine will be described.
First, the SAR-equipped machine speed measurement device 100 identifies a stationary object from an input SLC (Single Look Complex) image. Next, the SAR-equipped machine speed measurement device 100 decompresses the azimuth compression of the image including the selected target using the azimuth compression reference function expressed by Expression 12. Here, the slant range, rotation speed (Doppler center frequency) used in azimuth compression, and the speed of Equation 12 used when creating the SLC can be calculated from the additional information of the SAR image.
Next, the SAR-equipped machine speed measuring device 100 calculates a plurality of reference functions by changing the speed of the SAR-equipped machine and inputting it to the azimuth compression reference function shown in Expression 12. Then, the SAR-equipped machine speed measurement device 100 performs azimuth compression using each of the calculated reference functions. Here, the SAR-equipped machine speed measurement device 100 determines the image that is most tightened (clear) among the plurality of generated azimuth-compressed images. Then, the SAR-equipped machine speed measuring device 100 determines that the input speed is the speed of the SAR-equipped machine when calculating the azimuth compression reference function used to generate the image.

Next, details of each process will be described.
First, the SAR-equipped machine speed measurement device 100 specifies a stationary target from the input SLC image. Here, as shown in FIG. 5, characteristic points such as artificial structures that do not move during the synthetic opening time such as vegetation, rivers, and the sea are arbitrarily selected from the SLC image. Then, the selected range is cut out. Here, the SLC image is an image for one subpatch when the azimuth compression process (subpatch process) is performed several times in one scene. The cut-out width in the azimuth direction is limited by the synthetic aperture length, and if it is less than that, zero padding is performed. In addition, since azimuth compression is a process for improving compression in the azimuth direction, it is sufficient to have about several pixels in the range direction in consideration of the range migration described later.
The SAR-equipped machine speed measurement device 100 decompresses the azimuth compression of the m cutout images including each of the identified m target objects using the reference function represented by Expression 12. Then, the SAR-equipped machine speed measurement device 100 performs the following processing for each of the m targets specified, and measures the speed of the SAR-equipped machine based on each of the m targets.

  Next, the SAR-equipped machine speed measuring device 100 calculates a plurality of reference functions by changing the speed of the SAR-equipped machine and inputting it to the azimuth compression reference function shown in Expression 12. Here, the speed of the SAR-equipped machine is represented by a polynomial shown in Equation 13. In order to change the speed represented by the polynomial shown in Expression 13, the order n of the polynomial representing the speed, the maximum and minimum values of the coefficient of each order, and the step size for changing the speed are input. Equation 14 shows the step size calculation and the search parameters obtained from it.

Then, azimuth compression of the decompressed image is repeated while changing the speed of the SAR-equipped machine using Equations 12 and 13, and the combination of coefficients used when the most tightened image is obtained is searched. The speed coefficient is sequentially searched from the lower order to the higher order in consideration of the magnitude of the influence on the image. Details of the input of the speed coefficient will be described later.
It should be noted that range migration correction is performed based on the correction amount shown in Equation 15 corresponding to the speed before being multiplied by the reference function that has changed the speed.

  When these processes are performed on all m cut-out images, a speed coefficient matrix shown in Expression 16 is obtained. The numbers in the parentheses indicate the correspondence with the cut-out image.

Next, in order to remove coefficient fluctuations in the SLC image, the coefficient obtained from each cut-out image is averaged as shown in Equation 17 to obtain the speed of the SAR-equipped machine. The coefficient fluctuation in the SLC image occurs, for example, when each selected cut-out image is not a complete stationary body but has a fluctuation.

Further, the speed coefficient obtained by Expression 17 is temporarily stored, and as shown in FIG. 6, a higher resolution image can be reproduced by reflecting this result in the arbitrarily selected range of the SLC image. An arbitrary position can be selected with an arbitrary size as long as it is an image in the subpatch for which the velocity coefficient is calculated.

  Next, functions and operations of the SAR-equipped machine speed measuring apparatus 100 according to the first embodiment will be described with reference to FIGS. 7, 8, and 9.

FIG. 7 is a functional block diagram showing functions of the SAR-equipped machine speed measuring device 100 according to the first embodiment. As illustrated in FIG. 7, the SAR-equipped machine speed measurement device 100 includes an input unit 110, a processing unit 130, a storage unit 160, a display unit 170, a processing device 980, an input device 982, a storage device 984, and a display device 986. The input unit 110, the processing unit 130, the storage unit 160, the display unit 170, and the like are, for example, software, a program, or the like, but may be firmware having these functions.
The input unit 110 includes a data input unit 112, a reference function information input unit 114, and an accompanying information input unit 120. Here, the reference function information input unit 114 includes a speed input unit 116, a target specifying unit 122, and a SAR speed input unit 124. The processing unit 130 includes a range migration correction unit 132, a zero padding processing unit 134, an FFT (fast Fourier transform) processing unit 136, an azimuth compression processing unit 138, an IFFT (inverse fast Fourier transform) processing unit 140, and a reference function generation unit. 142, a speed determination unit 144, and a definition calculation unit 146. In addition, the storage unit 160 includes a data storage unit 162. The display unit 170 includes a data display unit 172.

  FIG. 8 is a flowchart showing a SAR-equipped machine speed measurement process that is an operation of measuring the speed of the SAR-equipped machine of the SAR-equipped machine speed measuring apparatus 100 according to the first embodiment. The SAR-equipped machine speed measurement process will be described with reference to FIGS.

First, in the data input step (S101), the data input unit 112 first selects arbitrarily m characteristic points that do not move during the synthetic aperture time as targets. Then, the data input unit 112 decompresses azimuth compression as described above to obtain data after range compression. Then, the data input unit 112 inputs the data after range compression.
Next, in the target specifying step (S102), the target specifying unit 122 does not move during the m synthetic opening times selected by the data input unit 112 from the range-compressed data input by the data input unit 112. Identify things. Then, the SAR-equipped machine speed measuring device 100 executes (processing group C) from (S102) to (S114), except for the following (S108), for each of the identified m targets. That is, the processing group C is repeated m times. That is, the process group C is a process of determining a combination of speed coefficients used in Expression 13 for each target.

Further, in the speed coefficient input step (S103), the speed input unit 116, for example, changes the order n of the polynomial representing the speed and the maximum value of the coefficient of each order for changing the speed represented by the polynomial shown in Expression 13. And a minimum value and a step size N ₀ to N _n for changing the speed are set.
Here, the polynomials of the 0th order to the nth order (n is an arbitrary natural number) representing the predicted speed are excluded from (S108) to (S114) for each order in order from a polynomial having a lower order to a polynomial having a higher order. (Processing group B) is repeated until the coefficient of the order is determined. That is, each coefficient of order _{a 0, a 1, ···,} determines the value in the order of _{a n.} Since the order is n, the processing group B is repeated n + 1 times. That is, the processing group B is processing for determining each order coefficient one by one.
Further, in the speed input step (S104), the speed input unit 116, the range of the coefficient set in (S103), by changing the coefficients in accordance with step size set, enter multiple predicted velocity _{V P} of the SAR mounting machine And stored in the storage device 984. In other words, the speed input unit 116, by changing according to N _n inputs a plurality of predicted velocity from the width N ₀ ticks from the coefficient a ₀ for polynomial of each order to a _n. Here, when the predicted speed represented by the nth order polynomial is input, the speed of the SAR-equipped machine determined by the speed determination unit 144 described below for the coefficients of the respective orders from the 0th order to the (n−1) th order is expressed ( n-1) A coefficient of each degree of a degree polynomial. Specific examples will be described later. Therefore, (processing group A) from (S104) to (S113) is repeated N ₀ ,..., N _n times as the step size of each order for each order. That is, the processing group A is processing for calculating the sharpness of an image to be described later for each step size.

Next, in the range migration correction step (S105), the range migration correction unit 132 is based on the predicted movement information of the SAR-equipped machine and the movement information of the target based on the predicted speed of the SAR-equipped machine input by the speed input unit 116. The correction amount C _r is calculated according to the relative distance r _PT (t) between the SAR-equipped machine and the target, and the range-compressed data input by the data input unit 112 based on the calculated correction amount C _r Range migration correction is performed and corrected data is generated. Here, the range migration correction unit 132 receives the distance r _PT (t) between the SAR-equipped machine and the target obtained in a reference function generation step (S109) described later, and based on the received r _PT (t) A migration correction amount _Cr is calculated. For example, the range migration correction unit 132 calculates the correction amount _Cr based on Equation 15.
Next, in the zero padding processing step (S106), the zero padding processing unit 134 fills the post-correction data generated by the range migration correction unit 132 with zeros, thereby setting the number of pixels of the post-correction data to a power of two. The padding data is generated by the processing device 980. Here, the zero padding processing unit 134 calculates the number of pixels to be padded with zeros based on, for example, Expressions 18 and 19. The reason why the number of pixels is a power of 2 is that the number of pixels must be a power of 2 in order to perform the fast Fourier transform (FFT). Therefore, the zero padding processing unit 134 calculates the number of pixels N _ftt in the azimuth direction for the fast Fourier transform, which is the smallest number of powers of 2 that is larger than the number of pixels in the cut out azimuth direction, as shown in Equation 18, for example. Then, as shown in Expression 19, 0 (zero) is filled by the number of pixels N _{zero_pad} that is zero-padded, which is the number of pixels that is insufficient.

Next, in the fast Fourier transform processing step (S 107), the FFT processing unit 136 performs FFT on the zero padded data generated by the zero padding processing unit 134 and generates post-FFT data by the processing device 980.

In part with the above processing, in the accompanying information input step (S108), the accompanying information input unit 120 uses the input device 982 to input image accompanying information accompanying the image such as the position of the SAR-equipped device.
Next, in the reference function generation step (S109), the reference function generation unit 142 includes the distance relationship information between the SAR-equipped machine and the target based on the predicted movement information of the SAR-equipped machine and the movement information of the predetermined target. and stores generated in the storage unit 984 a reference function by the processor 980 by a predicted velocity V _P of the speed input unit 116 is input. Here, the reference function generation unit 142 generates a reference function for each predicted speed input by the speed input unit 116. For example, the reference function generation unit 142 generates the reference function f _ref of Expression 12 above. And the reference function generating unit 142 _{outputs r} PT (t), to (S105). Further, the reference function generation unit 142 generates a reference function using only movement due to rotation as movement information of a predetermined target.
Next, in the fast Fourier transform processing step (S110), the FFT processing unit 136 performs FFT on the reference function generated by the reference function generation unit 142 and the post-FFT reference function is generated by the processing device 980.

Next, in the azimuth compression processing step (S111), the azimuth compression processing unit 138 performs the fast Fourier transform processing step (S107) based on the post-FFT reference function generated by the FFT processing unit 136 in the fast Fourier transform processing step (S110). Then, the data after FFT generated by the FFT processing unit 136 is azimuth-compressed, and the data after azimuth compression is generated by the processing device 980.
Next, in the inverse fast Fourier transform processing step (S112), the IFFT processing unit 140 performs IFFT (inverse fast Fourier transform) on the azimuth-compressed data that is azimuth-compressed by the azimuth compression processing unit 138, and processes the post-IFFT data on the processing device 980. Generate by.

Next, in the definition calculation step (S113), the definition of the target image specified by the target specifying unit 122, which is the target image indicated by the azimuth compressed data generated by the azimuth compression processing unit 138, is processed. Calculated by device 980.
Next, in the speed coefficient determination step (S114) (speed determination step), the speed determination unit 144 generates azimuth-compressed data having the highest definition image of the target calculated by the definition calculation unit 146. When the reference function used in the above is generated, the processing device 980 determines that the predicted speed used by the reference function generation unit is the speed of the SAR-equipped device, and stores it in the storage device 984.
Here, for example, the sharpness calculation unit 146 searches for the peak value of the amplitude representing the luminance of the pixel of the image indicated by the azimuth compressed data generated by the azimuth compression processing unit 138, and the higher the peak value is, the higher the image is. It is determined that it is clear.
That is, the speed determination unit 144 determines the speed of the SAR-equipped machine when the polynomials of each order are expressed in order from the polynomial with the lower order to the higher polynomial.
Next, in the average calculation step (S115) (speed determination step), the speed determination unit 144 stores the average predicted speed of the SAR-equipped machine stored for each of the m targets specified by the target specifying unit 122 as the SAR. It is determined that the speed of the machine. That is, as shown in Expression 17, the speed determination unit 144 obtains the speed of the SAR-equipped machine by averaging the coefficients of the respective orders.

  In the speed coefficient storage step (S116), the data storage unit 162 stores the speed of the SAR-equipped machine determined by the speed determination unit 144 in the storage device 984.

Next, a specific example of the input of the predicted speed by the speed input unit 116 in (S103) and (S104) will be described. As described above, the speed input unit 116, the coefficient from the coefficient a ₀ is varied in accordance with the width N ₀ ticks up a _n to N _n, in order from a low order polynomial to the degree higher polynomial for a polynomial of each order To decide. In addition, when inputting a predicted speed represented by an nth-order polynomial, it represents the speed of the SAR-equipped machine determined by the speed determination unit 144 described later with respect to the coefficients of the respective orders from the 0th order to the (n−1) th order (n -1) Coefficients of each degree of the degree polynomial.
That is, for a given target, the speed input unit 116 (S103) is the first time _{(α = 1), a 0_min} , a 0_max, from _{a 1_Min} the minimum value for the _{a 1} to _{a n} N ₀ is input and stored in the storage device 984 until _{an_min} . The speed input unit 116 (S104) and inputs are changed in accordance with the width _{N 0} increments from _{a 0_Min} to _{a 0_Max} for _{a 0.} Also, for each _{a 0} to be input by changing _inputs from _{a 1_Min} to _{a n_min.} Then, at (S114), the rate determining unit 144 determines a value of _{a 0.}
Then, the second time (alpha = 2), the speed input unit 116 (S103), and _{a 0} to the speed determination unit 144 determines the first _{time, a 1_min,} a _{1_max,} for from _{a 2} to _{a n} storing from _{a 2_Min} to _{a n_min} is the minimum value, type _{N 1} in the storage device 984. The speed input unit 116 (S104) and inputs are changed in accordance with the width _{N 1} increments for _{a 1} from _{a 1_Min} to _{a 1_max.} In addition, for each a ₁ that is changed and input, a ₀ determined by the speed determination unit 144 for the first time and a _{2_min} to _{an_min} are input. Then, at (S114), the rate determining unit 144 determines the value of _{a 1.}
Thereafter, the same processing is repeated, and at the α-th time, the speed input unit 116 at (S103), from a ₀ to a _α-2 determined by the speed determination unit 144 by the _{α-1th time} , and a _{α-1_min ,} a _{α-1_max,} stores from a _{Arufa_min} the minimum value for the a _alpha to _{a n} to _{a n_min,} by entering the n _alpha-1 in the storage device 984. In (S104), the speed input unit 116 inputs a _{α-1 by changing it} from a _{α-1_min} to a _{α-1_max according} to the step size N _α-1 . Also, for each a _α-1 that is changed and input, a ₀ to a _α-2 determined by the speed determination unit 144 for the _{α- 1th} time and a _{1_min} to _{an_min} are input. In (S114), the speed determination unit 144 determines the value of a _α-1 .

  A program that causes a computer to execute each step (process) of the SAR-equipped machine speed measurement process is a SAR-equipped machine speed measurement program. Moreover, the method provided with each step of the said SAR installation machine speed measurement process is a SAR installation machine speed measurement method.

FIG. 9 is a flowchart showing an image sharpening process, which is an operation for sharpening and displaying an image of a target observed by the SAR of the SAR-equipped machine speed measurement device 100 according to the first embodiment. The image sharpening process will be described with reference to FIGS.
First, in the data input step (S201), the data input unit 112 decompresses azimuth compression as described above to obtain data after range compression. Then, the data input unit 112 inputs the data after range compression. Here, the data input unit 112 may cut out a portion to be displayed and obtain data after range compression.
Next, in a speed coefficient reading step (S202), the SAR speed input unit 124 reads from the storage device 984 a speed coefficient representing the speed of the SAR-equipped machine determined by the speed determining unit 144 in the SAR-equipped machine speed measurement process.
In the speed coefficient input step (S203), the SAR speed input unit 124 inputs a speed coefficient representing the speed of the SAR-equipped machine read in (S202). That is, the reference function generation unit 142 generates a reference function based on the speed of the SAR-equipped machine obtained by the SAR-equipped machine speed measurement process.

The processing from (S204) to (S211) is the same as the processing from (S105) to (S112).
In the image display step (S212), the data display unit 172 displays the post-IFFT data generated by the IFFT processing unit 140 on the display device 986.

  Here, the reference function generated in (S208) is an example of an image reproduction reference function.

  According to the SAR-equipped machine speed measurement device, the SAR-equipped machine speed measurement program, and the SAR-equipped machine speed measurement method according to the first embodiment, the speed of the SAR-equipped machine is expressed by a high-order polynomial, and each coefficient is estimated from the image. This makes it possible to obtain a highly accurate SAR-equipped machine speed. That is, a clear image such as a target can be obtained. In addition, azimuth compression is performed one after another while changing the speed of the SAR-equipped machine for a plurality of small areas with a high S / N ratio selected by the user, and a speed coefficient with the maximum image formation degree is selected. Highly reliable and less affected by image quality.

Embodiment 2. FIG.
Next, a second embodiment will be described. In the first embodiment, the SAR-equipped machine speed measurement process for measuring the speed of the SAR-equipped machine and the image sharpening process for reproducing an image based on the SAR speed measured by the SAR speed measurement process have been described. In the second embodiment, a method for further improving the accuracy of the SAR-equipped machine speed measurement process will be described.

SAR has a system that can transmit and receive horizontal polarization and vertical polarization, respectively. That is, the SAR is a signal that is transmitted with vertical polarization and received with vertical polarization, a signal that is transmitted with horizontal polarization and received with vertical polarization, a signal that is transmitted with vertical polarization and received with horizontal polarization, In addition, it is possible to obtain information on four types of signals that are transmitted with horizontal polarization and received with horizontal polarization.
Therefore, the SAR-equipped machine speed measuring device 100 performs the SAR-equipped machine speed measurement process on the polarization images obtained based on the above four types of signals, and takes the average of the obtained SAR-equipped machine speeds. Thus, the speed of the SAR-equipped machine with higher accuracy can be obtained.
Further, a sharper image can be obtained by performing an image sharpening process based on the speed of the SAR-equipped device obtained from the polarization image based on each of the four types of signals.

Embodiment 3 FIG.
Next, Embodiment 3 will be described. In the third embodiment, a target speed measuring apparatus 200 that measures the speed of a target will be described.

First, based on FIG. 10, FIG. 11, the relative positional relationship of a SAR mounting machine and a target object is demonstrated. Here, it is assumed that the target is moving on the ground that rotates during the observation time (for example, several seconds). FIG. 10 is a diagram showing a relative relationship (distance) after t seconds between the SAR-equipped machine and the target. FIG. 11 is a diagram illustrating the movement of the target by the movement and rotation of the target itself in FIG.
Here, Expression 20 shows the distance vector between the SAR-equipped machine and the target after t seconds based on the movement of the SAR-equipped machine, and Expression 21 shows the speed vector of the target due to the movement and rotation of the target itself. From Equation 20 and Equation 21, Equation 22 is obtained as the relative motion (distance) between the SAR-equipped machine and the target after t seconds.

Here, assuming that the speed component of the SAR-equipped machine is constant, Expression 23 is obtained in consideration of the movement of the observation point in the range direction and the azimuth direction due to the earth rotation.

Further, as in the first embodiment, the speed of the SAR-equipped machine is expressed by a polynomial and matched with the azimuth direction of rotation. Here, _- a _{"V P = (v aE -V P_pre} ) ", _{"V P (t) = a 0} + a 1 t + ··· + a n t n, V P represents the relative velocity of the target .

From Equation 24, the azimuth compression reference function is calculated as follows.

  When the speed of the target of Expression 24 is generally expressed by a polynomial, the following relationship is obtained. Since the orders do not need to be the same in the range direction and the azimuth direction, the range direction is expressed in k-order and the azimuth direction is expressed in l-order.

By specifying the coefficient of each degree of the polynomial representing this speed, the range direction speed and the azimuth direction speed of the target are specified.

Next, an outline of a method by which the target velocity measuring apparatus 200 specifies the target velocity will be described.
First, the target velocity measuring apparatus 200 identifies one target that moves from the input SLC image. Next, the target velocity measurement apparatus 200 decompresses the azimuth compression of the selected target image using the azimuth compression reference function expressed by Equation 25. Here, the slant range, rotation speed (Doppler center frequency) used in azimuth compression, and the speed of Equation 12 used when creating the SLC can be calculated from the additional information of the SAR image.
Next, the target speed measurement apparatus 200 calculates a plurality of reference functions by changing the speed in the range direction and the speed of the target in the azimuth direction and inputting them to the azimuth compression reference function shown in Equation 25. Then, the target velocity measuring apparatus 200 performs azimuth compression using each reference function of the plurality of calculated reference functions. Here, the target velocity measuring apparatus 200 determines the image that is most tightened (clear) among the plurality of generated images after azimuth compression. Then, the target velocity measuring apparatus 200 determines that the velocity input when calculating the azimuth compression reference function used to generate the image is the velocity in the azimuth direction and the velocity in the range direction of the target. .

Next, details of each process will be described.
First, the target speed measurement apparatus 200 selects one target to be moved from the SLC image used in the SAR-mounted machine speed measurement process shown in the first embodiment as shown in FIG. 12, and sets a range including the target. cut. Here, the SLC image is an image for one subpatch when the azimuth compression process (subpatch process) is performed several times in one scene. The cut-out width in the azimuth direction is limited by the synthetic aperture length, and if it is less than that, zero padding is performed. Further, unlike the SAR-equipped machine speed measurement process shown in the first embodiment, the number of pixels to be sharpened by the range migration or more is selected in the range direction.
The target velocity measurement apparatus 200 decompresses the azimuth compression of the cut image using a reference function shown in Expression 25.

  Next, the target speed measurement apparatus 200 calculates a plurality of reference functions by changing the speed of the target and inputting the speed to the azimuth compression reference function shown in Expression 25. Here, the speed of the target is represented by the polynomial shown in Equation 26. In order to change the speed represented by the polynomial shown in Expression 26, the orders k and l of the polynomial representing the speed, the maximum and minimum values of the coefficient of each order, and the step size for changing the speed are input. Equation 27 shows the step size calculation and the search parameters obtained from it.

Then, azimuth compression of the decompressed image is repeated while changing the speed of the SAR-equipped machine using Expression 25 and Expression 26, and a combination of coefficients used when obtaining the most tightened image is searched. The speed coefficient advances the search sequentially from the range direction to the azimuth direction, and from the lower order to the higher order, which has a large influence on the range migration correction. Details of the input of the speed coefficient will be described later.
It should be noted that range migration correction is performed based on the correction amount shown in the above-described equation 15 corresponding to the speed before being multiplied by the reference function that has changed the speed.
Then, each coefficient of Expression 26 indicating the speed of the target is obtained. Based on this result, the true position of the target can be obtained.

  Next, functions and operations of the target velocity measuring apparatus 200 according to Embodiment 3 will be described based on FIGS. 13 and 14.

FIG. 13 is a functional block diagram illustrating functions of the target velocity measuring apparatus 200 according to the third embodiment. The function of the target speed measurement device 200 is substantially the same as the function of the SAR-equipped machine speed measurement device 100 according to the first embodiment. Accordingly, only the parts of the function of the target speed measuring device 200 that are different from the function of the SAR-equipped machine speed measuring device 100 according to the first embodiment will be described.
The target velocity measuring device 200 includes a synthetic opening time information input unit 118 and a target velocity input unit 126 in addition to the functions of the SAR-equipped machine speed measuring device 100 according to the first embodiment.

  FIG. 14 is a flowchart showing a target speed measurement process that is an operation of measuring the speed of the target of the target speed measuring apparatus 200 according to the third embodiment. The target speed measurement process will be described with reference to FIGS.

First, in the data input step (S301), the data input unit 112 first selects one target and cuts out a range including the target. Then, the data input unit 112 decompresses the azimuth compression of the image in the clipped range as described above, and obtains data after range compression. Then, the data input unit 112 inputs the data after range compression.
Next, in the synthetic aperture time information input step (S302), the synthetic aperture time information input unit 118 removes (S308) and (S309) while changing the synthetic aperture time information to be input (S302) to (S315). The processing group F up to is repeatedly executed. Processing unit F, for example, a synthetic aperture time T _A of the SAR and M division, repeated each of the M synthetic aperture time times. The synthetic aperture time information input unit 118 divides the synthetic aperture time into M based on, for example, Equation 28, and obtains _{TA_isar} .

Further, in the speed coefficient input step (S303), the speed input unit 116, for example, changes the order k and l of the polynomial representing the speed and the coefficient of each order for changing the speed represented by the polynomial shown in Expression 26. The maximum value and the minimum value, and the step widths K ₀ to K _k and L ₀ to L ₁ for changing the speed are set.
Here, the speed input unit 116 is a prediction speed in the range direction represented by a polynomial of 0th order to kth order (k is an arbitrary natural number) and a polynomial of 0th order to lth order (l is an arbitrary natural number). (S308) and (S309) are excluded for each order in order from a polynomial in which the order of each predicted speed to the predicted speed in the azimuth direction is higher to a higher polynomial (S303) to (S315) (processing group E) Is repeated to determine the coefficient of the order. In particular, the order coefficient is determined in order from the speed in the range direction to the speed in the azimuth direction when the speed of the target is expressed by a polynomial of each order. That is, the values are determined in the order of the coefficients a _{rT — 0} , a _{aT — 0} , a _{rT — 1} , a _{aT — 1} ,..., A _{rT — k} , a _{aT — l} of each order. Since the order is k, l, the processing group E is repeated (k + 1) + (l + 1) times. That is, the processing group E is processing for determining each order coefficient one by one.
In the speed input step (S304), the speed input unit 116 changes the coefficient in accordance with the set step size within the coefficient range set in (S303), and thus a plurality of predicted speeds V _rT and V _{aT of the} target object. Is stored in the storage device 984. That is, the speed input unit 116 _changes the coefficients a _{rT — 0} to a _{rT — k} for each degree of polynomial according to the step _sizes K ₀ to K _k , and _changes from the coefficients a _{aT — 0} to a a _{T — l} according to the step _sizes L ₀ to L _1. And input multiple predicted speeds. Here, when the predicted speed in the range direction represented by the kth order polynomial is input, the speed in the range direction in which the speed determination unit 144 determines each coefficient from the 0th order to the (k−1) th order (k−). 1) When inputting the predicted speed in the azimuth direction represented by the lth order polynomial as the coefficient of each degree of the degree polynomial, the azimuth in which the speed determination unit 144 has determined each coefficient from the 0th order to the (l−1) th order. The coefficient of each degree of the (l-1) degree polynomial representing the speed in the direction is used. Specific examples will be described later. Therefore, except for (S308) and (S309), from (S304) to (S315) (processing group D), K ₀ ,..., K _k or L ₀ , which is the step size of each order for each order. ..., L Repeat ₁ times. That is, the process group D is a process of calculating the sharpness of an image to be described later for each step size.

Next, in the range migration correction step (S305), the range migration correction unit 132 inputs the movement information of the SAR-equipped machine based on the speed of the SAR-equipped machine obtained by the SAR-equipped machine speed measurement process, and the speed input unit 116 inputs. A correction amount _Cr is calculated according to the relative distance r _PT (t) between the SAR-equipped machine and the target based on the movement information of the target based on the speed of the target, and based on the calculated correction amount _Cr . The range-compressed data input by the data input unit 112 is subjected to range migration correction to generate corrected data. Range migration correction amount for _{C r} calculation of is the same as that of the first embodiment (S105).
Next, the zero padding processing step (S306) and the fast Fourier transform processing step (S307) are the same as (S106) and (S107) in the first embodiment.

In the SAR-equipped machine speed measurement processing step (S308), the SAR-equipped machine speed measurement process described in the first embodiment is performed on the data after range compression input in (S301), and the speed of the SAR-equipped machine is measured.
In the incidental information input step (S309), the incidental information input unit 120 inputs image incidental information associated with the image such as the position of the SAR-equipped machine using the input device 982.
Next, in the reference function generation step (S310), the reference function generation unit 142 inputs distance information and speed information between the SAR-equipped machine and the target based on the movement information of the SAR-equipped machine and the predicted movement information of the target. A reference function is generated by the processing device 980 based on the predicted speeds V _rT and V _aT input by the unit 116 and stored in the storage device 984. Here, the reference function generation unit 142 generates a reference function for each predicted speed input by the speed input unit 116. For example, the reference function generation unit 142 generates the reference function f _ref of Expression 25 above. In addition, the reference function generation unit 142 outputs r _PT (t) to (S305). Also,
Next, the fast Fourier transform processing step (S311) is the same as (S110) of the first embodiment.

  Next, the azimuth compression processing step (S312) and the inverse fast Fourier transform processing step (S312) are the same as (S111) and (S112) of the first embodiment.

Next, in the definition calculation step (S314), the processing device 980 calculates the definition of the target image indicated by the azimuth compressed data generated by the azimuth compression processing unit 138.
Next, in the speed coefficient determination step (S315) (speed determination step), the speed determination unit 144 generates azimuth-compressed data having the highest definition of the target image calculated by the definition calculation unit 146. When the used azimuth compression reference function is generated, the processing device 980 determines that the predicted speed used by the reference function generation unit 142 is the target speed, and stores it in the storage device 984.
Here, for example, the sharpness calculation unit 146 searches for the peak value of the amplitude representing the luminance of the pixel of the image indicated by the azimuth compressed data generated by the azimuth compression processing unit 138, and the higher the peak value, the more the image It is determined that it is clear.
In other words, the speed determination unit 144 calculates the speed of the target in the order of the polynomial in each order in the order of the polynomial in the range direction to the polynomial in the azimuth direction from the polynomial in the low order to the polynomial in the high order. judge.
In the speed coefficient storage step (S316), the data storage unit 162 stores the speed of the target determined by the speed determination unit 144 in the storage device 984.

Next, a specific example of inputting the predicted speed by the speed input unit 116 in (S303) and (S304) will be described. As described above, the speed input unit 116, follow from the coefficient _{a RT_0} for polynomial of each order from the width _{K 0} ticks up _{a RT_k} to _{K k, L} from the width _{L 0} ticks from the coefficient _{a AT_0} until _{a aT_l l} The coefficients are determined in order from a polynomial having a lower order to a polynomial having a higher order, and from a polynomial representing a speed in the range direction to a polynomial representing a speed in the azimuth direction. In addition, when the predicted speed in the range direction represented by the kth order polynomial is input, the speed in the range direction in which the speed determination unit 144 determines each coefficient from the 0th order to the (k−1) th order (k−1). ) When inputting the predicted speed in the azimuth direction represented by the l-th order polynomial as the coefficient of each degree of the degree polynomial, the azimuth direction in which the speed determination unit 144 determines each coefficient from the 0th order to the (l-1) th order. It is assumed that the coefficient of each order of the (l-1) degree polynomial that represents the speed of.
That is, for a certain target, in (S303), the speed input unit 116, at the first time (first in the range direction, α = 1), is a zeroth order coefficient a _{rT —} 0 representing the speed in the range direction. Ask for. Therefore, the speed input unit 116, _{a RT_0_min} as the speed in the range direction, and stores _{a RT_0_max,} from _{a RT_1} from _{a RT_1_min} the minimum value for up to _{a RT_k} to _{a RT_k_min,} the storage device 984 to input _{K 0} . Also, as the speed of the azimuth direction _and stores the minimum value storage device 984 to input from _{a AT_0_min} to _{a AT_l_min} is about from _{a AT_0} to _{a aT_k.} The speed input unit 116 (S304) _and inputs are changed in accordance with the width _{K 0} increments from _{a RT_0_min} to _{a RT_0_max} for _{a rT_0.} In addition, for each _{arT_0} that is changed and input, _{arT_1_min} to _{arT_k_min} and _{aaT_0_min} to _{aaT_l_min} are input. In (S315), the speed determination unit 144 determines the value of _{arT_0} .
Next, in the second time (first time in the azimuth direction, α = 1), a _{aT — 0} , which is a first-order coefficient of a polynomial representing the velocity in the azimuth direction, is _obtained . In (S303), the speed input unit 116 sets _{arT_0} determined by the speed determination unit 144 for the first time as a speed in the range direction, and from _{arT_1_min} to _{arT_k_min} , which is the minimum value for _{arT_1} to _{arT_k.} The data is input and stored in the storage device 984. Also, as the speed of the azimuth _{direction, a aT_0_min,} a _{aT_0_max,} from _{a AT_1} from _{a AT_0_min} the minimum value of up to _{a AT_k} to _{a AT_l_min,} stored in the storage device 984 to input _{L 0.} The speed input unit 116 (S304) _and inputs are changed in accordance with the width _{L 0} in increments from _{a AT_0_min} to _{a AT_0_max} for _{a aT_0.} Also, for each a _{aT — 0} to be changed and input, a _{aT —} 1 — _min to a _{aT — k — min} and a _{rT —} 1 — _min to _{arT_k_min} are input. In (S315), the speed determination unit 144 determines the value of a _{aT — 0} .
Next, for the third time (second time in the range direction, α = 2), _{arT_1} , which is a first-order coefficient of a polynomial representing the speed in the range direction, is _obtained . The speed input unit 116 (S303), as the speed of the range direction, and _{a RT_0} the speed determining portion 144 has determined the first _time, the minimum value for a _{RT_1_min,} and _{a RT_1_max,} from _{a RT_2} to _{a rT_k a From rT_2_min} to _{arT_k_min} , K ₁ is input and stored in the storage device 984. Also, as the speed of the azimuth direction, and _{a AT_0} the speed determining unit 144 has determined a second _time, the minimum value storage device 984 to input and to _{a AT_l_min} from _{a AT_0_min} is about from _{a AT_1} to _{a AT_k} storage To do. The speed input unit 116 (S304) _and inputs are changed in accordance with the width _{K 1} increments from _{a RT_1_min} to _{a RT_1_max} for _{a rT_1.} In addition, for each _{arT_1} that is input while being changed, _{arT_2_min} to _{arT_k_min} and _{aaT_0_min} to _{aaT_l_min} are input. In (S315), the speed determination unit 144 determines the value of _{arT_1} .
Thereafter, the same processing is repeated, and at the αth time in the range direction, in (S303), the speed input unit 116 determines that the speed determination unit 144 has determined as the speed in the range direction by the α- _1th time in the range direction. To _{arT_α-2} , _{arT_α-1_min} , _{arT_α-1_max} , and _{arT_α} to _{arT_k} , which are the minimum values _{arT_α_min} to _{arT_k_min} , K _α-1 is input and stored in the storage device 984 To do. Also, as the speed of the azimuth direction, and from _{a AT_0} the speed determining portion 144 has determined by alpha-1 th azimuth direction until _{a aT_α-2,} which is the minimum value for the _{a aT_α-1} to _{a aT_l a aT_α −1_min} to a _{aT — l_min} are input and stored in the storage device 984. Then, in (S304), the speed input unit 116 changes and inputs _{arT_α-1} from _{arT_α-1_min} to _{arT_α-1_max according} to the step size _{Kα -1} . In addition, for each _{arT_α-1} that is changed and input, the speed determination unit 144 determines from _{arT_0} to _{arT_α-2} at the α- _1th time in the range direction, from _{arT_α_min} to _{arT_k_min} , and in the azimuth direction. _Input from a _{aT — 0} to a _{aT — α-2} determined by the speed determination unit 144 by the α- _{1th time and} from a _{aT —} α-1 _{— min} to a _{aT — l_min} . Then, in (S315), the speed determination unit 144 determines the value of _{arT_α-1} .
In the αth time in the azimuth direction, in (S303), the speed input unit 116 sets the speed in the range direction from _{arT_0} to _{arT_α-1} determined by the speed determination unit 144 up to the _αth time in the range direction, and _{arT_α.} To _{arT_k} , the minimum values _{arT_α_min} to _{arT_k_min} are input and stored in the storage device 984. Further, as the speed in the azimuth direction, from a _{aT_0} to a _{aT_α-2} determined by the α- _1th time in the azimuth direction, a _{aT_α-1_min} , a _{aT_α-1_max} , a _{aT_α} to a _{aT_l} for the _{a AT_arufa_min} to _{a AT_l_min} the minimum value is stored in the storage device 984 to input L _alpha-1. In (S304), the speed input unit 116 inputs a _{aT_α-1 by changing it} from a _{aT_α-1_min} to a _{aT_α-1_max according} to the step size L _α-1 . For each a _{aT_α-1} that is changed and input, α-th in the azimuth direction, from _{arT_0} to _{arT_α-1} determined by the speed determination unit 144 in the _αth time in the range direction, from _{arT_α_min} to _{arT_k_min.} From a _{aT_0} to a _{aT_α-2} determined by the speed determination unit 144 by the first time, and from a _{aT_α_min} to a _{aT_l_min} are input. In (S315), the speed determination unit 144 determines the value of a _{aT_α-1} .

  According to the target velocity measuring apparatus 200, the target velocity measuring method, and the target velocity measuring program according to the third embodiment, the velocity of the moving target can be measured and the sharpened moving target can be measured. Images can be obtained.

Embodiment 4 FIG.
Next, a fourth embodiment will be described. In the fourth embodiment, a method for improving the target speed measurement processing system described in the third embodiment by using polarization images based on the four types of signals described in the second embodiment will be described.

The target speed measurement apparatus 200 receives the speed of the SAR-equipped machine measured by the SAR-equipped machine speed measurement process shown in the first embodiment or the second embodiment, and inputs the polarization image based on each of four types of signals. The target speed measurement process shown in the third embodiment is executed. Then, the target velocity measuring apparatus 200 obtains a target velocity and a sharpened image for each of the polarization images based on the four types of signals.
In addition, the target speed measuring apparatus 200 calculates the speed of the SAR-equipped machine measured by the SAR-equipped machine speed measurement process and the speed of the target measured by one polarization image of polarization images based on four types of signals. As an input, a polarization image other than the one polarization image is sharpened.
By this processing, a clearer image of the target can be obtained.

The figure which shows an example of the external appearance of the SAR mounting machine speed measuring apparatus 100 concerning embodiment. The figure which shows an example of the hardware constitutions of the SAR mounting machine speed measurement apparatus 100 in embodiment. The figure showing the relative relationship (distance) of the SAR loading machine and the target after t seconds. The figure which shows the movement by rotation of the target in FIG. The figure which shows the outline | summary which selects a target object from a SLC image. The figure which shows the outline | summary which selects the part which reproduces | regenerates a high-resolution image from a SLC image. FIG. 3 is a functional block diagram showing functions of the SAR-equipped machine speed measurement device 100 according to the first embodiment. 5 is a flowchart showing a SAR-equipped machine speed measurement process that is an operation of measuring the speed of the SAR-equipped machine of the SAR-equipped machine speed measuring apparatus 100 according to the first embodiment. 6 is a flowchart showing an image sharpening process that is an operation for sharpening and displaying an image of a target observed by the SAR of the SAR-equipped machine speed measurement device 100 according to the first embodiment. The figure showing the relative relationship (distance) of the SAR loading machine and the target after t seconds. The figure which shows the movement of the target by the movement and rotation of the target itself in FIG. The figure which shows the outline | summary which selects the target which moves from the SLC image used for the SAR mounting machine speed measurement process shown in Embodiment 1. FIG. FIG. 10 is a functional block diagram showing functions of a target velocity measuring apparatus 200 according to a third embodiment. 10 is a flowchart showing a target speed measurement process that is an operation of measuring a target speed of the target speed measuring apparatus 200 according to the third embodiment.

Explanation of symbols

  100 SAR-equipped machine speed measurement device, 110 input unit, 112 data input unit, 114 reference function information input unit, 116 speed input unit, 118 synthetic opening time information input unit, 120 associated information input unit, 122 target identification unit, 124 SAR speed input unit, 126 target speed input unit, 130 processing unit, 132 range migration correction unit, 134 zero padding processing unit, 136 FFT processing unit, 138 azimuth compression processing unit, 140 IFFT processing unit, 142 reference function generation unit, 144 Speed determination unit, 146 definition calculation unit, 160 storage unit, 162 data storage unit, 170 display unit, 172 data display unit, 901 CRT display device, 902 K / B, 903 mouse, 904 FDD, 905 CDD, 908 database 909 System unit 910 Server, 911 CPU, 912 bus, 913 ROM, 914 RAM, 915 communication board, 920 magnetic disk unit, 921 OS, 922 window system, 923 program group, 924 file group, 931 telephone, 932 FAX machine, 940 Internet, 941 Gateway, 942 LAN, 980 processing device, 982 input device, 984 storage device, 986 display device.

Claims (15)

In a target velocity measuring apparatus for measuring a velocity of a target observed by a SAR (Synthetic Aperture Radar),
A data input unit for inputting the range-compressed data obtained by performing range compression on the target data observed by the SAR and storing the data in the storage device;
A speed input unit that inputs a plurality of predicted speeds , which are a plurality of predicted speeds of the target object, and changes a coefficient of an n-th order (n is an arbitrary natural number) polynomial representing the predicted speed , and stores them in a storage device;
The distance information between the SAR-equipped machine and the target based on the movement information of the SAR-equipped machine and the predicted movement information of the predetermined target, and a plurality of predicted speeds of the plurality of predicted speeds input by the speed input unit. a reference function generating unit that generates a reference function,
Based on the reference function of a plurality of reference functions that the reference function generating unit has generated a azimuth compressing unit that generates a data after multiple azimuth compression to azimuth compression data after the range compression,
A sharpness calculating unit that exits calculate the sharpness of the image of the azimuth compressing section each of a plurality of azimuth compression data after the target exhibiting the data after azimuth compression generated,
When the reference function used to generate the azimuth-compressed data having the highest definition image of the target calculated by the definition calculation unit is generated, the predicted speed used by the reference function generation unit is set as the target target speed measuring device, characterized in that it comprises a speed determination unit for determine a constant if there at a speed of the object. The speed input unit is configured to change a coefficient for a polynomial of each degree in order from a polynomial having a low degree to a polynomial having a high degree from a polynomial of 0 degree to n order (n is an arbitrary natural number) representing a predicted speed. Enter the predicted speed,
The speed determination unit determines the speed of the target when represented by a polynomial of each degree in order from a polynomial having a low degree of polynomial to a polynomial having a high degree,
When the predicted speed represented by the nth order polynomial is input, the speed input unit represents the speed of the target for which the speed determination unit has determined the coefficients of the respective orders from the 0th order to the (n−1) th order ( 2. The target velocity measuring apparatus according to claim 1, wherein n-1) is a coefficient of each degree of the degree polynomial. The speed input unit is represented by a range-direction predicted speed represented by a polynomial of 0th order to kth order (k is an arbitrary natural number) and a polynomial of 0th order to lth order (l is an arbitrary natural number). In order from the low-order polynomial to the high-order polynomial of each prediction speed with the prediction speed in the azimuth direction, input a plurality of prediction speeds by changing the coefficient for each order polynomial of each prediction speed,
The speed determination unit sequentially determines the speed of the target in the order of the polynomial in each order from the low-order polynomial to the high-order polynomial, from the speed in the range direction to the speed in the azimuth direction,
When the speed input unit inputs a predicted speed in the range direction represented by a k-th order polynomial, the speed input unit represents the speed in the range direction in which the speed determination unit determines each coefficient from the 0th order to the (k−1) th order. (K-1) When the predicted speed in the azimuth direction represented by the lth order polynomial is input as the coefficient of each order of the order polynomial, the speed determination unit determines each coefficient from the 0th order to the (l-1) th order. 2. The target velocity measuring apparatus according to claim 1, wherein the target velocity measuring device is a coefficient of each degree of the (1-1) degree polynomial representing the determined velocity in the azimuth direction. The reference function generation unit inputs each prediction speed of the plurality of prediction speeds input by the speed input unit to the reference function expression 2 obtained from Expression 1 representing the distance relationship information between the SAR-equipped machine and the target. target speed measuring apparatus according to claim 1, wherein the generating a plurality of reference functions to 3.
The target velocity measuring device further includes:
A correction amount is calculated based on Equation 3, and a range migration correction unit that performs range migration correction on the range-compressed data input by the data input unit based on the calculated correction amount,
The azimuth compressing section, target according to claim 1, characterized in that to generate the data after azimuth compression to azimuth compression the corrected data the range migration correction unit has range migration correction to 4 Speed measuring device.
The target velocity measuring device further includes:
A synthetic aperture time information input unit for inputting a plurality of synthetic aperture time information having a start time of the synthetic aperture time and an end time of the synthetic aperture time by an input device,
The reference function generation unit includes each synthetic aperture time information of the plurality of synthetic aperture time information input by the synthetic aperture time information input unit, each predicted speed of the plurality of predicted rates input by the speed input unit, and the distance target speed measuring apparatus according to claim 1, wherein the generating by the processor a plurality of reference functions by the relationship information to 5. In a target velocity measuring apparatus for measuring a velocity of a target observed by a SAR (Synthetic Aperture Radar),
A data input unit that inputs range-compressed data obtained by performing range compression on the data observed by the SAR and stores the data in a storage device;
A speed input unit that inputs a plurality of predicted speeds of the SAR-equipped machine and stores them in a storage device;
A target selection unit that selects a predetermined target as a selection target from the targets included in the range-compressed data input by the data input unit; and
Distance information on the distance between the SAR-equipped machine and the selected target based on the predicted movement information of the SAR-equipped machine and the movement information of the selected target selected by the target selection unit, and the SAR-equipped machine input by the speed input unit A reference function generation unit that generates a plurality of SAR speed measurement reference functions by the processing device according to each of the plurality of prediction speeds and stores the reference function in a storage device;
Azimuth compression in which the range-compressed data is azimuth-compressed and a plurality of azimuth-compressed data is generated by a processor based on each SAR speed measurement reference function of the plurality of SAR speed measurement reference functions generated by the reference function generation unit A processing unit;
A definition calculation unit that calculates the definition of an image of the selected target indicated by each azimuth-compressed data of the plurality of azimuth-compressed data generated by the azimuth compression processing unit;
When generating the reference function used to generate the azimuth-compressed data having the highest definition image of the selected target calculated by the definition calculation unit, the prediction speed used by the reference function generation unit is calculated. A speed determination unit that determines by the processing device that the speed is the SAR-equipped machine,
The speed input unit inputs a plurality of predicted speeds of a target target to be measured for speed among targets included in the range-compressed data input by the data input unit ,
The reference function generating unit, and the speed determining unit determines the SAR of mobile information and the object target of SAR mounting machine based on the speed of the mounting machine predicted movement information and the basis was SAR-based unit and the object target A plurality of target speed measurement reference functions are generated based on the distance relation information and the predicted speeds of the predicted speeds of the target target input by the speed input unit,
The azimuth compression processing unit azimuth-compresses the range-compressed data based on each target velocity measurement reference function of the plurality of target velocity measurement reference functions generated by the reference function generation unit, and performs a plurality of azimuth compressions. Generate data,
The sharpness calculation unit calculates the sharpness of the image of the azimuth compressing section each of a plurality of azimuth compression data after the target target showing the data after azimuth compression generated,
The speed determination unit generates the reference function used to generate the azimuth-compressed data having the highest definition of the target target image calculated by the definition calculation unit. It is determined that the predicted speed used by is the speed of the target target. In a target velocity measurement program for measuring the velocity of a target observed by a SAR (Synthetic Aperture Radar),
A data input processing SAR is you enter range compression after data range compression for the data of the target of observation,
A plurality of predicted velocity of the target, and n-th (n is an arbitrary natural number) speed input processing you enter multiple prediction rate coefficients of the polynomial are varied in representing the predicted velocity,
The distance information between the SAR-equipped machine and the target based on the movement information of the SAR-equipped machine and the predicted movement information of the predetermined target, and a plurality of predicted speeds of the plurality of predicted speeds input in the speed input process. a reference function generating process that generates a reference function,
Based on the reference function of a plurality of reference functions generated by the reference function generating process, and the azimuth compressing that generates the data after a plurality of azimuth compression to azimuth compression data after the range compression,
A sharpness calculation processing for leaving calculate the sharpness of the image of the azimuth compressing each of a plurality of azimuth compression data after the target exhibiting the data after azimuth compression generated by,
When generating the reference function used to generate the azimuth-compressed data having the highest definition of the target image calculated in the definition calculation process, the target speed is the predicted speed used in the reference function generation process. target speed measurement program for causing performed when there at a rate of goods and speed determination process determine the constant to the computer. The speed input process is performed by changing coefficients for polynomials of respective orders in order from a polynomial having a lower degree to a polynomial having a higher degree from a polynomial of 0th order to nth order (n is an arbitrary natural number) representing the predicted speed. Enter the predicted speed,
The speed determination process determines the speed of the target when represented by polynomials of respective orders in order from a polynomial having a lower polynomial order to a higher polynomial,
In the speed input process, when a predicted speed represented by an nth-order polynomial is input, the speed of the target for which the coefficient of each order from the 0th order to the (n−1) th order is determined by the speed determination process ( 9. The target speed measurement program according to claim 8, wherein the coefficient is a coefficient of each order of (n-1) degree polynomial. The speed input process is represented by a range-direction predicted speed represented by a polynomial of 0th order to kth order (k is an arbitrary natural number) and a polynomial of 0th order to lth order (l is an arbitrary natural number). In order from the low-order polynomial to the high-order polynomial of each prediction speed with the prediction speed in the azimuth direction, input a plurality of prediction speeds by changing the coefficient for each order polynomial of each prediction speed,
The speed determination process sequentially determines the speed of the target in the order of the polynomial in each order from the low-order polynomial to the high-order polynomial, from the speed in the range direction to the speed in the azimuth direction,
In the speed input process, when the predicted speed in the range direction represented by the k-th order polynomial is input, the speed in the range direction in which the coefficients from the 0th order to the (k−1) th order are determined in the speed determination process is represented. (K-1) When the predicted speed in the azimuth direction represented by the l-order polynomial is input as the coefficient of each degree of the order polynomial, the coefficients from the 0th order to the (l-1) -th order are input in the speed determination process. 9. The target speed measurement program according to claim 8 , wherein the target speed measurement program uses a coefficient of each degree of a (1-1) degree polynomial representing the determined speed in the azimuth direction. In the reference function generation process, each predicted speed of the plurality of predicted speeds input in the speed input process is input to the reference function expression 2 obtained from Expression 1 representing the distance relationship information between the SAR-equipped machine and the target. The target speed measurement program according to any one of claims 8 to 10, wherein a plurality of reference functions are generated. The target speed measurement program further includes:
A correction amount is calculated based on Equation 3, and based on the calculated correction amount, the computer is caused to execute range migration correction processing for performing range migration correction on the range-compressed data input in the data input processing,
The target speed according to any one of claims 8 to 11 , wherein the azimuth compression processing generates azimuth-compressed data by performing azimuth compression on the corrected data subjected to the range migration correction in the range migration correction processing. Measurement program. The target speed measurement program further includes:
Synthetic aperture time of the start time and the synthetic aperture enter a plurality of synthetic aperture time information and a end time of the synthetic aperture time information input process is executed by a computer,
The reference function generation process includes the synthetic aperture time information of the plurality of synthetic aperture time information input in the synthetic aperture time information input process, the predicted speeds of the plurality of predicted speeds input in the speed input process, and the distance target speed measurement program according to any of claims 8 to 12, characterized in that to generate a plurality of reference functions by the relationship information. In a target velocity measurement program for measuring the velocity of a target observed by a SAR (Synthetic Aperture Radar),
A data input process you enter data after range compression that range compression on the data SAR has observed,
A speed input processing you enter multiple predicted velocity of the SAR mounting machine,
A target selection process for selecting a predetermined target from the targets included in the range-compressed data input in the data input process;
Distance information on the distance between the SAR-equipped machine and the selected target based on the predicted movement information of the SAR-equipped machine and the movement information of the selected target selected in the target selection process, and the SAR-equipped machine input in the speed input process a reference function generating process that generates a plurality of reference functions for SAR rate measured by a plurality of the predicted velocity of the predicted velocity of,
Based on the SAR rate measurement reference function of a plurality of SAR velocity measurement reference function generated by the reference function generating process, and the azimuth compressing that generates the data after a plurality of azimuth compression to azimuth compression data after the range compression ,
A sharpness calculation processing for leaving calculate the sharpness of the image of the selected target indicated by each azimuth compression after data of a plurality of data after azimuth compression generated by the azimuth compressing,
When generating the reference function used to generate the azimuth-compressed data having the highest definition image of the selected target calculated in the definition calculation process, the predicted speed used in the reference function generation process is If it is a rate of SAR mounting machine to perform rate determination process determine the constant to the computer,
The speed input process inputs a plurality of predicted speeds of the target target to be measured for speed among the targets included in the range-compressed data input in the data input process ,
The reference function generating process, with the rate determination process SAR mounting machine based on the predicted movement information of the mobile information and the object target of SAR mounting machine based on the speed of the determined SAR mounting machine with the above object target A plurality of target speed measurement reference functions are generated based on the distance relation information and each predicted speed of the plurality of predicted speeds of the target target input in the speed input process,
In the azimuth compression processing, the range-compressed data is azimuth-compressed based on each target velocity measurement reference function of the plurality of target velocity measurement reference functions generated in the reference function generation processing, and a plurality of azimuth-compressed data Produces
The sharpness calculation processing, and calculates the sharpness of the image of the object target indicated by each azimuth compression after data of a plurality of after azimuth compression data generated by the azimuth compressing,
The speed determination process is performed when the reference function used to generate the azimuth-compressed data having the highest definition of the target target image calculated in the definition calculation process is generated. A target speed measurement program for determining that the predicted speed used in step 1 is the speed of a target target. In the target velocity measuring method of the target velocity measuring apparatus for measuring the velocity of the target observed by SAR (Synthetic Aperture Radar),
A data input step in which the storage device inputs and stores the range-compressed data obtained by subjecting the target data observed by the SAR to range compression;
A speed input step in which a storage device inputs and stores a plurality of predicted speeds of a target that are changed by a coefficient of an n-th order (n is an arbitrary natural number) polynomial representing the predicted speed ; ,
Each prediction of a plurality of predicted speeds input in the speed input step and distance information between the SAR mounted machine and the target based on the movement information of the SAR mounted machine and the predicted movement information of the predetermined target. a reference function generating step for storing a plurality of reference functions raw form and by the speed,
A processing unit, based on each reference function of the plurality of reference functions generated in the reference function generation step, azimuth compression the range-compressed data to generate a plurality of azimuth compressed data,
A processing device calculates a definition of a target image indicated by each azimuth-compressed data of the plurality of azimuth-compressed data generated in the azimuth compression step; and
Used in the reference function generation step when the processing device generates the reference function used to generate the azimuth-compressed data having the highest definition of the target image calculated in the definition calculation step. And a speed determination step for determining that the predicted speed is the speed of the target.