Radar device, echo image generation method and echo image generation program

Abstract

RADAR DEVICE, ECHO IMAGE GENERATION METHOD AND ECHO IMAGE GENERATION PROGRAM For the purpose of generating an echo image showing a more accurate detection result of an object, a radar device (101) is provided with: an acquisition unit that acquires echo data indicating a correspondence relationship between a position in a detection object area and the level of a reflected wave reflected at the position by an electromagnetic wave transmitted via an antenna (11); a detection unit that detects an object based on the echo data; a land determination unit that determines whether or not the object is on land based on the area of the object; a port determination unit that determines whether or not the position of the vessel (1) is in a port based on the distance (D) between the vessel (1) and the land; a threshold determination unit that determines a threshold for the level of the reflected wave according to the determination result of whether or not the vessel (1) is in a port; and a generation unit that generates an echo image based on the threshold and the echo data. (FIG. 1)

Description

RADAR DEVICE, ECHO IMAGE GENERATION METHOD AND ECHO IMAGE GENERATION PROGRAM

[0001] This disclosure relates to a radar device, echo image generation method and echo image generation program.Background

[0002] Conventionally, a technology for accurately detecting a target has been developed. For example, Patent Literature 1 (Japanese Unexamined Patent Application Publication No. 2009 -103581) discloses the following automatic gain control device. Specifically, the automatic gain control device compares the amplitude of a received signal obtained from a radar search area with a predetermined threshold and outputs a received signal having an amplitude equal to or greater than the predetermined threshold. The automatic gain control device includes a determination unit for determining whether the position of the vessel is within or outside the port area, a threshold calculation unit for calculating a first threshold to be used outside the port area or a second threshold to be used inside the port area based on the determination result of the determination unit, and an output control unit for controlling the gain of the received signal using the threshold calculated by the threshold calculation unit.

[0003] Patent Literature 1 - Japanese Unexamined Patent Application Publication No. 2009-103581Patent Literature 2 - Japanese Unexamined Patent Application Publication No. 2008-26034Patent Literature 3 - Japanese Unexamined Patent Application Publication No. 2014-89056

[0004] There is a desire for a technology capable of generating an echo image showing a more accurate detection result of an object beyond the technology described in Patent Literature 1.

[0005] The present disclosure has been made in order to solve the above-mentioned problems, and an object thereof is to provide a radar device capable of generating an echo image showing a more accurate detection result of an object, an echo image generating method, and an echo image generating program.

[0006] (1) The radar device of the present disclosure is a radar device to be mounted on a vessel, and includes: an acquisition unit that acquires echo data indicating a correspondence between a position in a detection target area and a level of a reflected wave reflected at the position by an electromagnetic wave transmitted via an antenna; a detection unit that detects an object based on the echo data; a land determination unit that determines whether or not the target is on land based on the area of the target; a land determination unit that determines whether or not the position of the vessel is within a port based on the distance between the vessel and the land; a threshold determination unit that determines a threshold for the level of the reflected wave according to the determination result of whether or not the position of the vessel is within the port; and a generation unit that generates an echo image in the detection target area based on the threshold and the echo data, The generation unit generates an echo image based on the threshold value determined according to whether or not the position of the vessel is within the port and the echo data.

[0007] For example, it is possible to generate an echo image showing the detection result of a relatively small object in the port while generating an echo image in which noise outside the port is removed, so that erroneous detection and detection omissions of the object may be suppressed. Moreover, the generation unit which determines whether or not the object is on land based on the area of the object and determines whether or not the position of the vessel is in the port based on the distance between the vessel and the land may more accurately determine whether or not the vessel is in the port based on the positional relationship with the land in the detection object area. Therefore, it is possible to generate an echo image showing a more accurate detection result of the object.

[0008] (2) In (1), the land determination unit may further determine whether or not the object is on land based on the width of the object in the azimuth direction and the width of the object in the distance direction.

[0009] Such a configuration may suppress erroneous detection of the object having a large area such as a large vessel as being on land and may more accurately detect the land in the detection object area.

[0010] (3) In (1) or (2), the threshold determination unit may adjust the threshold based on the degree of crowding of noise echoes around the vessel.

[0011] With such a configuration, an echo image may be generated using a more appropriate threshold for suppressing false detection and omission of detection of a target.

[0012] (4) In (3), the threshold determination unit may adjust the threshold determined when the position of the vessel is determined to be within the port.

[0013] With such a configuration, for example, an echo image in which noise within the port is eliminated may be generated.

[0014] (5) In (3) or (4), the threshold determination unit may adjust the threshold based on the degree of crowding of the noise echo in the area where the distance from the vessel is within the distance between the vessel and the land nearest to the vessel.

[0015] With such a configuration, an echo image in which noise such as sea surface reflection occurring in the vicinity of the vessel is eliminated may be generated.

[0016] (6) In any of (1) to (5), the port determination unit may determine whether or not the position of the vessel is within the port based on the distance between the vessel and the land nearest to the vessel.

[0017] With such a configuration, the processing load in determining whether or not the position of the vessel is within the port may be reduced.

[0018] (7) The echo image generation method of the present disclosure is an echo image generation method in a radar device to be mounted on a vessel, which acquires echo data showing the correspondence between a position in a detection object area and the level of a reflected wave reflected by an electromagnetic wave transmitted through an antenna at the position, detects an object based on the echo data, determines whether or not the object is on land based on the area of the object, determines whether or not the position of the vessel is within the port based on the distance between the vessel and the land, determines a threshold value for the level of the reflected wave according to the determination result of whether or not the position of the vessel is within the port, and generates an echo image in the detection object area based on the threshold value and the echo data.

[0019] By the method of generating an echo image based on the threshold value determined according to whether or not the position of the vessel is within the port and the echo data, for example, an echo image showing the detection result of a relatively small object in the port may be generated while an echo image in which noise outside the port is removed may be generated, so that erroneous detection and detection leakage of the object may be suppressed. Furthermore, by a method of determining whether or not the target is on land based on the area of the target and determining whether or not the position of the vessel is in the port based on the distance between the vessel and the land, it is possible to more accurately determine whether or not the vessel is located in the port based on the positional relationship with the land in the detection target area. Therefore, an echo image showing a more accurate detection result of the target may be generated.

[0020] (8) The echo image generation program of the present disclosure is an echo image generation program used in a radar device to be mounted on a vessel, wherein a process for acquiring echo data indicating a correspondence relationship between a position in a detection object area and a level of a reflected wave reflected at the position by an electromagnetic wave transmitted via an antenna, a process for detecting an object based on the echo data, a process for determining whether or not the object is on land based on the area of the object, a process for determining whether or not the position of the vessel is in a port based on the distance between the vessel and the land, a process for determining a threshold value for the level of the reflected wave according to a determination result of whether or not the position of the vessel is in the port, and a process for generating an echo image in the detection object area based on the threshold value and the echo data;, a program for making a computer execute the following:

[0021] Thus, by a configuration for generating an echo image based on the threshold value determined according to whether or not the position of the vessel is in the port and the echo data, for example, an echo image showing a detection result of a relatively small object in the port may be generated, while an echo image in which noise outside the port is removed may be generated, and thus false detection and detection omissions of the object may be suppressed. Further, by a configuration for determining whether or not the object is on land based on the area of the object and determining whether or not the position of the vessel is in the port based on the distance between the vessel and the land, it is possible to more accurately determine whether or not the vessel is located in the port based on a positional relationship with the land in the detection object area. Therefore, an echo image showing a more accurate detection result of the object may be generated.Advantageous Effects of the Invention

[0022] According to the present disclosure, an echo image showing a more accurate detection result of the object may be generated.

[0023] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein. The diagrams are for illustration only, which thus is not a limitation of the present invention. Moreover, those skilled in the art will understand that the drawings are not to scale. FIG. 1 is a diagram showing the configuration of a radar device according to an embodiment of the present disclosure; FIG. 2 is a diagram showing a part of detection data generated by a setting unit in a radar device according to an embodiment of the present disclosure; FIG. 3 is a diagram for explaining land determination processing by a setting unit in a radar device according to an embodiment of the present disclosure; FIG. 4 is a flowchart showing an example of an operation when a radar device according to an embodiment of the present disclosure performs display processing; FIG. 5 is a flowchart showing an example of an operation when a radar device according to an embodiment of the present disclosure determines a threshold value for display; FIG. 6 is a flowchart showing an example of an operation when a radar device according to an embodiment of the present disclosure performs adjustment processing;

[0024] Example apparatus are described herein. Other example embodiments or features may further be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. In the following detailed description, reference is made to the accompanying drawings, which form a part thereof.

[0025] The example embodiments described herein are not meant to be limiting. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the drawings, may be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

[0026] Embodiments of the present disclosure will be described below with reference to the drawings. The same reference numerals are assigned to the same or equivalent parts in the drawings, and the description thereof will not be repeated. Furthermore, at least a part of the following embodiments may be optionally combined.

[0027] FIG. 1 is a diagram showing the configuration of a radar device according to an embodiment of the present disclosure. Referring to FIG. 1, the radar device 101 includes an antenna 11, a transceiver (transceiver) unit 12, a signal processing unit 13, a setting unit 14, a display processing unit 15, and a storage unit 16. The signal processing unit 13 is an example of an acquisition unit. The setting unit 14 is an example of a detection unit, an example of a land determination unit, an example of a port determination unit, and an example of a threshold determination unit. The display processing unit is an example of a generation unit. Some or all of the functions of the transceiver 12, the signal processing unit 13, the setting unit 14, and the display processing unit 15 are realized by a processing circuit (circuit) including, for example, one or more processors. The storage unit 16 is, for example, a non-volatile memory included in the processing circuit.

[0028] The radar device 101 is mounted on a vessel 1. The radar device 101 displays an echo image indicating the position of object S of another vessel or the like in the detection target area Ta on a display device (not shown). For example, the detection target area Ta is an area inside a circle of a predetermined size centered on the vessel 1.

[0029] The transceiver 12 transmits electromagnetic waves and receives reflected waves at a transceiver timing according to a predetermined sweep cycle Cy1. More specifically, during a sweep period T1 of a predetermined length starting from the transceiver timing, the transceiver 12 transmits electromagnetic waves to the area Da to be divided via the antenna 11, and receives reflected waves reflected from the transmitted electromagnetic waves via the antenna 11. The area Da to be divided is a fan-shaped area in which the area Ta to be detected is divided into N pieces along the azimuth direction. N is an integer of 2 or more.

[0030] The transceiver 12 digitally converts the echo signal indicating the received reflected wave to generate digital data Dd. The transceiver 12 repeatedly transmits the electromagnetic wave and generates the digital data Dd while rotating the antenna 11 so that the azimuth angle in the transmission direction of the electromagnetic wave changes by a predetermined angle for each sweep period Cy1. Each time the transceiver 12 generates the digital data Dd, it outputs the generated digital data Dd to the signal processing unit 13. Hereinafter, the period of one rotation of the antenna 11 is also referred to as the scan period Cy2.

[0031] (Signal Processing Unit) The signal processing unit 13 generates echo data E indicating the correspondence between the position in the detection object area Ta and the level of the reflected wave reflected by the electromagnetic wave transmitted through the antenna 11 at the position.

[0032] For example, each time the signal processing unit 13 receives the digital data Dd from the transceiver 12, it generates divided echo data Ed, which is echo data E indicating the correspondence between the position in the division object area Da and the echo level at the position, based on the received digital data Dd. The echo level at each position of the divided echo data Ed indicates the level of the reflected wave reflected at the position. Each time the signal processing unit 13 generates the divided echo data Ed, it stores the generated divided echo data Ed in the storage unit 16.

[0033] (Setting Unit) 1 [Object detection processing] The setting unit 14 detects the object S based on the echo data E. For example, the setting unit 14 performs object detection processing at a set timing according to the scan period Cy2. More specifically, the setting unit 14 acquires N pieces of divided echo data Ed from the storage unit 16 every time the N pieces of divided echo data Ed accumulated in the storage unit 16 by the signal processing unit 13 reach N pieces. By connecting the N pieces of divided echo data Ed acquired, the setting unit 14 generates connected echo data Et which is echo data E showing the correspondence between the position in the detection object area Ta and the echo level at the position.

[0034] The setting unit 14 compares the echo level of each position in the generated connected echo data Et with a predetermined detection threshold V1. Then, the setting unit 14 generates detection data EtB in which the value of the echo level at the position where the echo level is equal to or greater than the detection threshold V1 is converted to "1" and the value of the echo level at the position where the echo level is less than the detection threshold V1 is converted to "0".

[0035] FIG. 2 is a view showing a part of detection data EtB generated by the setting unit in the radar device according to the embodiment of the present disclosure. FIG. 2 shows a plurality of cells C arranged in a matrix on two-dimensional coordinates corresponding to the detection object area Ta. For example, each cell C corresponds to an echo level detection position. A hatched cell C is a cell C whose echo level value is "1." A non-hatched cell C is a cell C whose echo level value is "0". Moreover, for example, one row of cells C in two-dimensional coordinates corresponds to one division target area Da. In practice, the azimuth direction is a direction on a curve and the shape of the cells C is represented by a curve. In FIG. 2, however, for the sake of simplicity, the azimuth direction is a direction on a straight line and the shape of the cells C is a square.

[0036] Referring to FIG. 2, the setting unit 14 generates detection data EtB showing the correspondence between a plurality of cells C arranged in a matrix on two-dimensional coordinates corresponding to the detection target area Ta and the echo level of the cells C. The setting unit 14 detects an object S in the detection target area Ta based on the generated detection data EtB. Hereinafter, a cell C having an echo level of "1" is referred to as "cell C1" and a cell C having an echo level of "0" is referred to as "cell C0".

[0037] For example, the setting unit 14 calculates the echo size, which is the size of the echo EC represented by the cell C1, and determines whether the echo EC is the object S or the noise echo Ns according to the calculated echo size.

[0038] More specifically, based on the position of the cell C1 in the n-th column and the position of the cell C1 in the (n-1)-th column adjacent to the n-th column in the direction opposite to the rotational direction of the antenna 11, the setting unit 14 determines whether the cell C1 in the n-th column and the cell C1 in the (n-1)-th column correspond to a common echo EC. where n is an integer of 1 or more.

[0039] In the continuity determination process, the setting unit 14 detects, among one or more cells C1 that are continuous in the distance direction in the n-th column, a falling cell C1d in which the adjacent cell C in the electromagnetic wave transmission direction is the cell C0, and a rising cell C1u in which the adjacent cell C in the opposite direction of the electromagnetic wave transmission direction is the cell C0.

[0040] When detecting the falling cell C1d and the rising cell C1u in the nth column, the setting unit 14 determines that the cell C1 between the falling cell C1d and the rising cell C1u in the nth column and the cell C1 in the (n-1) column correspond to the common echo EC, if the cell C1 in the (n-1) column belongs to a row between the row of the falling cell C1d and the row of the rising cell C1u.

[0041] On the other hand, if the cell C1 in the (n-1)-th column does not belong to a row between the row of the falling cell C1d and the row of the rising cell C1u, the setting unit 14 determines that the cell C1 between the falling cell C1d and the rising cell C1u in the n-th column and the cell C1 in the (n-1)-th column are cells C1 corresponding to separate echo ECs.

[0042] The setting unit 14 performs continuity determination processing for each column in the detection data EtB to detect the position, number, and size of echo ECs in the detection target area Ta. Instead of the continuity determination processing described above, the setting unit 14 may detect the position, number, and size of echo ECs in the detection target area Ta according to the method described in Patent Literature 2 (Japanese Unexamined Patent Application Publication No. 2008 -26034) or Patent Literature 3 (Japanese Unexamined Patent Application Publication No. 2014 -89056).

[0043] The setting unit 14 calculates the number of cells C1 corresponding to the detected echo ECs as the echo size of the detected echo ECs. When the echo size of the echo ECs is equal to or larger than the predetermined value, the setting unit 14 determines that the echo ECs are the target S. On the other hand, when the echo size of the echo ECs is less than the predetermined value, the setting unit 14 determines that the echo ECs are the noise echoes Ns.

[0044] (2) [Land Determination Processing] FIG. 3 is a diagram for explaining land determination processing by the setting unit in the radar device according to the embodiment of the present disclosure. Referring to FIG. 3, the setting unit 14 performs land determination processing to determine whether or not the object S is land L based on the area of the object S, the width W1 of the object S in the azimuth direction, and the width W2 of the object S in the distance direction at the setting timing according to the scan period Cy2.

[0045] More specifically, when the setting unit 14 detects the object S, it calculates the number of cells Nc, which is the number of cells C1 corresponding to the object S, the width W1 of the object S in the azimuth direction, and the width W2 of the object S in the distance direction. The number of cells Nc corresponds to the area of the object S in plan view. The setting unit 14 compares the calculated number of cells Nc and the widths W1 and W2 with predetermined determination thresholds Tha, Thb, and Thc, respectively.

[0046] When the number of cells Nc of the object S is equal to or greater than the determination threshold Tha, the width W1 of the object S is equal to or greater than the determination threshold Thb, and the width W2 of the object S is equal to or greater than the determination threshold Thc, the setting unit 14 determines that the object S is land L.

[0047] On the other hand, when the number of cells Nc of the object S is less than the determination threshold Tha, the width W1 of the object S is equal to or less than the determination threshold Thb, or the width W2 of the object S is equal to or less than the determination threshold Thc, the setting unit 14 determines that the object S is not land L.

[0048] (3) [Port Determination Processing] The setting unit 14 performs port determination processing to determine whether the position of the vessel 1 is in a port or not based on the distance D between the vessel 1 and land L at the set timing according to the scan period Cy2. For example, the setting unit 14 determines whether the position of the vessel 1 is in a port or not based on the distance D between the vessel 1 and the nearest land L from the vessel 1.

[0049] More specifically, the setting unit 14 calculates the distance D between the vessel 1 and the nearest land L from the vessel 1. Then, the setting unit 14 compares the calculated distance D with a predetermined determination threshold value Thd.

[0050] If the distance D is less than or equal to the determination threshold Thd, the setting unit 14 determines that the position of the vessel 1 is within the port.

[0051] On the other hand, if the distance D is greater than the determination threshold Thd, the setting unit 14 determines that the position of the vessel 1 is not within the port.

[0052] (4) [Determination of Display Threshold Vd] The setting unit 14 determines the display threshold Vd for the level of the reflected wave in accordance with the determination result of whether or not the position of the vessel 1 is within the port at the setting timing according to the scan period Cy2.

[0053] More specifically, the storage unit 16 stores display thresholds Vd1 and Vd2 which are display thresholds Vd. The display threshold Vd1 is smaller than the display threshold Vd2.

[0054] When the setting unit 14 determines that the position of the vessel 1 is in the port, the setting unit determines the display threshold Vd used for generating the display data EtD to be the display threshold Vd1. Then, the setting unit 14 outputs threshold information It1 which is threshold information It is indicating that the display threshold Vd1 should be used to the display processing unit 15.

[0055] On the other hand, when the setting unit 14 determines that the position of the vessel 1 is not in the port, the display threshold Vd for the level of the reflected wave is set to the display threshold Vd2. Then, the setting unit 14 outputs threshold information It2 which is threshold information It is indicating that the display threshold Vd2 should be used to the display processing unit 15.

[0056] (5) [Adjustment Processing] The setting unit 14 adjusts the display threshold Vd based on the degree of crowding of the noise echo Ns around the vessel 1 at the setting timing according to the scan period Cy2. For example, the setting unit 14 adjusts the display threshold Vd1 determined when the position of the vessel 1 is determined to be in the port based on the density of noise echoes Ns in the area within the distance D between the vessel 1 and the nearest land L from the vessel 1.

[0057] More specifically, after outputting the threshold information It1 to the display processing unit 15, in the port determination processing at a new setting timing according to the scan period Cy2, when the position of the vessel 1 is determined to be in the port, the setting unit 14 calculates the noise echo number Cnt, which is the number of noise echoes Ns in a circular target area Ac centered on the vessel 1 and having a radius equal to the length of the distance D. The setting unit 14 calculates a divisor Nd obtained by dividing the calculated noise echo number Cnt by the area of the target area Ac. Then, the setting unit 14 compares the calculated divisor Nd with predetermined adjustment thresholds M1 and M2. Here, the adjustment threshold M1 is assumed to be smaller than the adjustment threshold M2.

[0058] When the divisor Nd is equal to or greater than the adjustment threshold M2, the setting unit 14 outputs an adjustment instruction A1 to the display processing unit 15 to add the predetermined adjustment value Vm1 to the display threshold Vd1.

[0059] On the other hand, when the divisor Nd is equal to or less than the adjustment threshold M1, the setting unit 14 outputs an adjustment instruction A2 to the display processing unit 15 to subtract the predetermined adjustment value Vm2 from the display threshold Vd1. The adjustment value Vm2 may be the same as or different from the adjustment value Vm1.

[0060] On the other hand, when the divisor Nd is larger than the adjustment threshold M1 and smaller than the adjustment threshold M2, the setting unit 14 does not output the adjustment instructions A1 and A2 to the display processing unit 15.

[0061] (Display Processing Unit) The display processing unit 15 generates an echo image in the detection target area Ta based on the display threshold Vd and the echo data E, and displays the echo image on a display device not shown.

[0062] More specifically, the display processing unit 15 acquires the divided echo data Ed from the storage unit 16 every time the divided echo data Ed is stored in the storage unit 16 by the signal processing unit 13. The display processing unit 15 compares the echo level of each position in the acquired divided echo data Ed with the display threshold Vd indicated by the latest threshold information It received from the setting unit 14.

[0063] Then, the display processing unit 15 generates display data EtD in which the value of the echo level at the position where the echo level is equal to or greater than the display threshold Vd is converted to "1" and the value of the echo level at the position where the echo level is less than the display threshold Vd is converted to "0".

[0064] The display processing unit 15 generates a divided echo image which is an echo image of the area Da to be divided based on the generated display data EtD. More specifically, the display processing unit 15 generates a divided echo image indicating that the object S exists at the position where the echo level is "1" and the object S does not exist at the position where the echo level is "0". The display processing unit 15 displays the generated divided echo image on a display device not shown.

[0065] The display processing unit 15 displays an echo image consisting of N divided echo images by generating and displaying the divided echo image N times. When the display processing unit 15 newly generates a divided echo image of the area Da to be divided after displaying the echo image, it updates the divided echo image of the area Da to be divided displayed on the display device to the newly generated divided echo image.

[0066] For example, when the display processing unit 15 receives the adjustment instruction A1 from the setting unit 14 after receiving threshold information It1 indicating that the display threshold Vd1 should be used from the setting unit 14, it adds the adjustment value Vm1 to the display threshold Vd1. Then, the display processing unit 15 performs the comparison processing described above using the display threshold Vd1 to which the adjustment value Vm1 has been added.

[0067] For example, when the display processing unit 15 receives the adjustment instruction A2 from the setting unit 14 after receiving threshold information It1 indicating that the display threshold Vd1 should be used from the setting unit 14, the adjustment value Vm2 is subtracted from the display threshold Vd1. Then, the display processing unit 15 performs the comparison processing described above using the display threshold Vd1 from which the adjustment value Vm2 has been subtracted.

[0068] [Flow of Operation] The radar device according to the embodiment of the present disclosure includes a computer including a memory, and a processor such as a CPU in the computer reads and executes a program including part or all of the steps of the following flowchart from the memory. The program of the apparatus may be installed externally. The program of the apparatus circulates in a state stored in a recording medium or via a communication line.

[0069] FIG. 4 is a flowchart showing an example of an operation when the radar device according to the embodiment of the present disclosure performs display processing.

[0070] Referring to FIG. 4, the radar device 101 first waits for transceiver timing according to the sweep cycle Cy1 (NO in step S11), and when the transceiver timing arrives (YES in step S11), transmits electromagnetic waves to the area Da to be divided and receives reflected waves (step S12).

[0071] Next, the radar device 101 digitally converts the echo signal indicating the received reflected waves to generate digital data Dd, and generates divided echo data Ed based on the digital data Dd (step S13).

[0072] Next, the radar device 101 compares the echo level of each position in the divided echo data Ed with the display threshold Vd, and generates display data EtD in which the value of the echo level at the position where the echo level is equal to or greater than the display threshold Vd is converted to "1" and the value of the echo level at the position where the echo level is less than the display threshold Vd is converted to "0" (step S14).

[0073] Next, the radar device 101 generates a divided echo image of the area Da to be divided based on the generated display data EtD (step S15).

[0074] Next, the radar device 101 displays the generated divided echo image on a display device (not shown) (step S16).

[0075] Next, the radar device 101 waits for a new transceiver timing (step S 11: NO).

[0076] FIG. 5 is a flowchart showing an example of an operation when the radar device according to the embodiment of the present disclosure determines the display threshold.

[0077] Referring to FIG. 5, the radar device 101 first waits for a setting timing according to the scan period Cy2 (step S 21: NO), and when the setting timing arrives (step S 21: YES), generates the concatenated echo data Et by connecting N pieces of the divided echo data Ed (step S22).

[0078] Next, the radar device 101 generates detection data EtB in which the value of the echo level at the position where the echo level is equal to or greater than the detection threshold V1 is converted to "1" and the value of the echo level at the position where the echo level is less than the detection threshold V1 is converted to "0" (step S23).

[0079] Next, the radar device 101 detects the object S in the detection target area Ta based on the detection data EtB (step S24).

[0080] Next, the radar device 101 determines whether the object S is land L based on the area of the detected object S, the width W1 of the object S in the azimuth direction, and the width W2 of the object S in the distance direction (step S25).

[0081] Next, the radar device 101 performs port determination processing. More specifically, the radar device 101 compares the distance D between the vessel 1 and the nearest land L from the vessel 1 with the determination threshold Thd (step S26).

[0082] Next, if the distance D is less than or equal to the determination threshold Thd (YES in step S27), the radar device 101 determines that the position of the vessel 1 is in the port (step S28).

[0083] Next, the radar device 101 determines the display threshold Vd used to generate the display data EtD to be the display threshold Vd1 (step S29), and waits for a new setting timing (NO in step S21).

[0084] On the other hand, if the distance D is larger than the judgment threshold Thd (NO in step S27), the radar device 101 determines that the position of the vessel 1 is not in the port (step S30).

[0085] Next, the radar device 101 determines the display threshold Vd used to generate the display data EtD to be the display threshold Vd2 (step S31), and waits for a new setting timing (NO in step S21).

[0086] FIG. 6 is a flowchart showing an example of an operation when the radar device according to the embodiment of the present disclosure performs adjustment processing. After determining that the position of the vessel 1 is in the port in the port determination processing (step S26) shown in FIG. 5, if the position of the vessel 1 is again determined to be in the port in the port determination processing (step S26) performed with the arrival of the next setting timing, the radar device 101 executes the processing shown in FIG. 6.

[0087] Referring to FIG. 6, first, the radar device 101 calculates the noise echo number Cnt, which is the number of noise echoes Ns in the target area Ac (step S41).

[0088] Next, the radar device 101 calculates the divisor Nd obtained by dividing the noise echo number Cnt by the area of the target area Ac (step S42).

[0089] Next, the radar device 101 compares the calculated divisor Nd with the adjustment thresholds M1 and M2 (step S43).

[0090] Next, if the divisor Nd is equal to or greater than the adjustment threshold M2 (YES in step S44), the radar device 101 adds the adjustment value Vm1 to the display threshold Vd1 used for the comparison processing described above (step S45) and ends the processing.

[0091] On the other hand, if the divisor Nd is equal to or less than the adjustment threshold M1 (NO in step S44 and YES in step S 46), the radar device 101 subtracts the adjustment value Vm2 from the display threshold Vd1 used for the comparison processing described above (step S47) and ends the processing.

[0092] On the other hand, if the divisor Nd is larger than the adjustment threshold M1 and smaller than the adjustment threshold M2 (NO in step S44 and NO in step S 46), the radar device 101 maintains the display threshold Vd1 and ends the process.

[0093] In the radar device 101 according to the embodiment of the present disclosure, the setting unit 14 is configured to determine whether the object S is land L based on the area of the object S, the width W1 of the object S in the azimuth direction, and the width W2 of the object S in the distance direction, but this is not limited to the configuration. The setting unit 14 may be configured to perform land determination processing based on the area of the object S without using the widths W1 and W2.

[0094] In the radar device 101 according to the embodiment of the present disclosure, the setting unit 14 is configured to perform adjustment processing, but this is not limited to the configuration. The setting unit 14 may be configured not to perform adjustment processing.

[0095] In the radar device 101 according to the embodiment of the present disclosure, the setting unit 14 is configured to perform target detection processing, land determination processing, port determination processing, and determination of the display threshold Vd at the setting timing according to the scan period Cy2, but this is not limited to the configuration. The setting unit 14 may be configured to perform target detection processing or the like based on the echo data E generated during the period M times the scan period Cy2 at the setting timing according to the scan period Cy2, for example, M times the scan period Cy2. Here, M is a positive number.

[0096] The above embodiment should be considered to be exemplary in all respects and not restrictive. The scope of the present invention is indicated by the claims, not by the above description, and it is intended to include all modifications within the meaning and scope of the claims.Terminology

[0097] It is to be understood that not necessarily all objects or advantages may be achieved in accordance with any particular embodiment described herein. Thus, for example, those skilled in the art will recognize that certain embodiments may be configured to operate in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

[0098] All of the processes described herein may be embodied in, and fully automated via, software code modules executed by a computing system that includes one or more computers or processors. The code modules may be stored in any type of non-transitory computer-readable medium or other computer storage device. Some or all the methods may be embodied in specialized computer hardware.

[0099] Many other variations than those described herein will be apparent from this disclosure. For example, depending on the embodiment, certain acts, events, or functions of any of the algorithms described herein can be performed in a different sequence, can be added, merged, or left out altogether (e.g., not all described acts or events are necessary for the practice of the algorithms). Moreover, in certain embodiments, acts or events can be performed concurrently, e.g., through multi-threaded processing, interrupt processing, or multiple processors or processor cores or on other parallel architectures, rather than sequentially. In addition, different tasks or processes can be performed by different machines and / or computing systems that can function together.

[0100] The various illustrative logical blocks and modules described in connection with the embodiments disclosed herein can be implemented or performed by a machine, such as a processor. A processor can be a microprocessor, but in the alternative, the processor can be a controller, microcontroller, or state machine, combinations of the same, or the like. A processor can include electrical circuitry configured to process computer-executable instructions. In another embodiment, a processor includes an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable device that performs logic operations without processing computer-executable instructions. A processor can also be implemented as a combination of computing devices, e.g., a combination of a digital signal processor (DSP) and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Although described herein primarily with respect to digital technology, a processor may also include primarily analog components. For example, some or all of the signal processing algorithms described herein may be implemented in analog circuitry or mixed analog and digital circuitry. A computing environment can include any type of computer system, including, but not limited to, a computer system based on a microprocessor, a mainframe computer, a digital signal processor, a portable computing device, a device controller, or a computational engine within an appliance, to name a few.

[0101] Conditional language such as, among others, "can," "could," "might" or "may," unless specifically stated otherwise, are otherwise understood within the context as used in general to convey that certain embodiments include, while other embodiments do not include, certain features, elements and / or steps. Thus, such conditional language is not generally intended to imply that features, elements and / or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements and / or steps are included or are to be performed in any particular embodiment.

[0102] Disjunctive language such as the phrase "at least one of X, Y, or Z," unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y, and / or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain embodiments require at least one of X, at least one of Y, or at least one of Z to each be present.

[0103] Any process descriptions, elements or blocks in the flow diagrams described herein and / or depicted in the attached figures should be understood as potentially representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or elements in the process. Alternate implementations are included within the scope of the embodiments described herein in which elements or functions may be deleted, executed out of order from that shown, or discussed, including substantially concurrently or in reverse order, depending on the functionality involved as would be understood by those skilled in the art.

[0104] Unless otherwise explicitly stated, articles such as "a" or "an" should generally be interpreted to include one or more described items. Accordingly, phrases such as "a device configured to" are intended to include one or more recited devices. Such one or more recited devices can also be collectively configured to carry out the stated recitations. For example, "a processor configured to carry out recitations A, B and C" can include a first processor configured to carry out recitation A working in conjunction with a second processor configured to carry out recitations B and C. The same holds true for the use of definite articles used to introduce embodiment recitations. In addition, even if a specific number of an introduced embodiment recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations).

[0105] It will be understood by those within the art that, in general, terms used herein, are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.).

[0106] For expository purposes, the term "horizontal" as used herein is defined as a plane parallel to the plane or surface of the floor of the area in which the system being described is used or the method being described is performed, regardless of its orientation. The term "floor" can be interchanged with the term "ground" or "water surface." The term "vertical" refers to a direction perpendicular to the horizontal as just defined. Terms such as "above," "below," "bottom," "top," "side," "higher," "lower," "upper," "over," and "under," are defined with respect to the horizontal plane.

[0107] As used herein, the terms "attached," "connected," "mated," and other such relational terms should be construed, unless otherwise noted, to include removable, moveable, fixed, adjustable, and / or releasable connections or attachments. The connections / attachments can include direct connections and / or connections having intermediate structure between the two components discussed.

[0108] Numbers preceded by a term such as "approximately," "about," and "substantially" as used herein include the recited numbers, and also represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms "approximately," "about," and "substantially" may refer to an amount that is within less than 10% of the stated amount. Features of embodiments disclosed herein preceded by a term such as "approximately," "about," and "substantially" as used herein represent the feature with some variability that still performs a desired function or achieves a desired result for that feature.

[0109] It should be emphasized that many variations and modifications may be made to the above-described embodiments, the elements of which are to be understood as being among other acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.

[0110] Representative embodiments of the present invention will be listed below.

[0111] (1) A radar device (101), comprising: an acquisition unit configured to acquire echo data indicating a correspondence between a position in a detection target area (Ta) and a level of a reflected wave reflected at the position by an electromagnetic wave transmitted via an antenna (11); a detection unit configured to detect a target (S) based on the echo data; a land determination unit configured to determine whether or not the target (S) is land (L) based on the area of the target (S); a port determination unit configured to determine whether or not the position of the target (S) is within a port; a threshold determination unit configured to determine a threshold for the level of the reflected wave in accordance with the determination result of whether or not the position of the target (S) is within the port; and a generation unit configured to generate an echo image in the detection target area (Ta) based on the threshold and the echo data.

[0112] (2) The radar device (101) according to (1), wherein the land determination unit is further configured to determine whether or not the target (S) is land (L) based on the width (W1,W2) of the target (S) in the azimuth direction and the width (W1,W2) of the target (S) in the distance (D) direction.

[0113] (3) The radar device (101) according to (1), wherein the threshold determination unit is further configured to adjust the threshold based on the degree of crowding of noise echoes in the vicinity of a vessel (1).

[0114] (4) The radar device (101) according to (3), wherein the threshold determination unit is further configured to adjust the threshold determined in the case where the position of the target (S) is determined to be within the port.

[0115] (5) The radar device (101) according to (3), wherein the threshold determination unit is further configured to adjust the threshold based on the degree of crowding of noise echoes in the area within the distance (D) between the target (S) and the nearest land from the target (S).

[0116] (6) The radar device (101) according to (1), wherein the threshold determination unit is further configured to determine whether or not the target (S) is within the port based on the distance (D) between the target (S) and the nearest land from the target (S).

[0117] (7) A method of generating an echo image in a radar device (101), comprising: acquiring echo data indicating a correspondence between a position in a detection target area (Ta) and the level of a reflected wave reflected at the position by an electromagnetic wave transmitted via an antenna (11); detecting a target (S) based on the echo data; determining whether or not the target (S) is land based on the area of the target (S); determining whether or not the position of the target (S) is within the port; determining a threshold for the level of the reflected wave in accordance with the determination result of whether or not the position of the target (S) is within the port; and generating an echo image in the detection target area (Ta) based on the threshold and the echo data.

[0118] (8) A non-transient computer readable medium containing program instructions for causing a computer to execute the method of: acquiring echo data indicating a correspondence between a position in a detection target area (Ta) and the level of a reflected wave reflected at the position by an electromagnetic wave transmitted via an antenna (11); detecting a target (S) based on the echo data; determining whether or not the target (S) is land based on the area of the target (S); determining whether or not the position of the target (S) is within the port; determining a threshold for the level of the reflected wave in accordance with the determination result of whether or not the position of the target (S) is within the port; and generating an echo image in the detection target area (Ta) based on the threshold and the echo data.

[0119] 1: Vessel, 11: Antenna, 12: Transceiver, 13: Signal Processing Unit, 14: Setting Unit, 15: Display Processing Unit, 16: Storage Unit, 101: Radar Device, EtB: Detection Data, C0: Cell, C1d: Falling Cell, C1u: Rising Cell, S: Target, L: Land, Ac: Target Area, W1, W2: Width, D: Distance

Claims

1. A radar device (101), comprising: an acquisition unit configured to acquire echo data indicating a correspondence between a position in a detection target area (Ta) and a level of a reflected wave reflected at the position by an electromagnetic wave transmitted via an antenna (11); a detection unit configured to detect a target (S) based on the echo data; a land determination unit configured to determine whether or not the target (S) is land (L) based on the area of the target (S); a port determination unit configured to determine whether or not the position of the target (S) is within a port; a threshold determination unit configured to determine a threshold for the level of the reflected wave in accordance with the determination result of whether or not the position of the target (S) is within the port; and a generation unit configured to generate an echo image in the detection target area (Ta) based on the threshold and the echo data.

2. The radar device (101) according to claim 1, wherein the land determination unit is further configured to determine whether or not the target (S) is land (L) based on the width (W1,W2) of the target (S) in the azimuth direction and the width (W1,W2) of the target (S) in the distance (D) direction.

3. The radar device (101) according to claim 1, wherein the threshold determination unit is further configured to adjust the threshold based on the degree of crowding of noise echoes in the vicinity of a vessel (1).

4. The radar device (101) according to claim 3, wherein the threshold determination unit is further configured to adjust the threshold determined in the case where the position of the target (S) is determined to be within the port.

5. The radar device (101) according to claim 3, wherein the threshold determination unit is further configured to adjust the threshold based on the degree of crowding of noise echoes in the area within the distance (D) between the target (S) and the nearest land from the target (S).

6. The radar device (101) according to claim 1, wherein the threshold determination unit is further configured to determine whether or not the target (S) is within the port based on the distance (D) between the target (S) and the nearest land from the target (S).

7. A method of generating an echo image in a radar device (101), comprising acquiring echo data indicating a correspondence between a position in a detection target area (Ta) and the level of a reflected wave reflected at the position by an electromagnetic wave transmitted via an antenna (11); detecting a target (S) based on the echo data; determining whether or not the target (S) is land based on the area of the target (S); determining whether or not the position of the target (S) is within the port; determining a threshold for the level of the reflected wave in accordance with the determination result of whether or not the position of the target (S) is within the port; and generating an echo image in the detection target area (Ta) based on the threshold and the echo data.

8. A non-transient computer readable medium containing program instructions for causing a computer to execute the method of: acquiring echo data indicating a correspondence between a position in a detection target area (Ta) and the level of a reflected wave reflected at the position by an electromagnetic wave transmitted via an antenna (11); detecting a target (S) based on the echo data; determining whether or not the target (S) is land based on the area of the target (S); determining whether or not the position of the target (S) is within the port; determining a threshold for the level of the reflected wave in accordance with the determination result of whether or not the position of the target (S) is within the port; and generating an echo image in the detection target area (Ta) based on the threshold and the echo data.

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