JPH03138583A - Processor for pseudo image due to side lobe - Google Patents

Abstract

PURPOSE:To easily identify a pseudo image and a real video by matching the center of a main lobe while regarding the video which has the highest signal intensity among equal-distance images as the real video and deciding a video at a position where it intersects the center of the side lobe as the pseudo image. CONSTITUTION:When the video data in all directions from a transmission/reception part 2 are stored to an input image memory 3a they are stored in a storage means 6 by specific areas. A video data read means 7 informs a distance calculating means 8 of the coordinate values of the image at the closest position among the video data which are stored 6, and the distance calculating means 8 calculates the distance. Then a video data retrieval means 9 retrieves videos on the circumference which whose radius is equal to the distance and a signal intensity detecting means 10 regards the video which has the largest signal intensity among the images on the circumference as the real video and sends its coordinate value to a side lobe pseudo image decision means 13. The means 13 matches the center line of the main lobe of a pseudo image decision angle 17 with the coordinate position of the real video and decides the video at the position on the circumference where it intersects the center line of the side lobe as the pseudo image and a side lobe pseudo image removing means 14 removes it.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device that determines artifacts due to side lobes based on signal strength and processes the artifacts.

[Prior art] For example, in radar etc. (hereinafter referred to as target tracking device),
When emitting radio waves, the antenna has directional characteristics, and side lobes cause the image to appear in a different direction from the target.

Generally, this image is called a false image due to side lobes, and in order to remove this false image, the sensitivity of the display device must be lowered, or in general, the directional characteristics of the antenna are fixed depending on the radar used, and the directional characteristics can be changed. The angle between the main lobe and the side lobe allows us to determine in what direction the side lobe artifacts appear, and we also compare the signal strength of the reflected echo image due to the side lobe with the signal intensity of the reflected echo image due to the main lobe. Due to the weak nature of the image, operators had to distinguish between false images based on their experience.

[Problems to be Solved by the Invention] In the conventional target tracking device as described above, in order to remove the false images caused by side lobes, the operator has to lower the sensitivity of the display, or it is difficult to remove the false images caused by side lobes. The problem was that the operator could not easily identify the true image because the operator had to make the determination based on his experience since he could tell whether the image was visible in the direction.

The present invention has been made to solve this problem, and uses the reflection intensity of sidelobe artifacts to automatically identify false images based on their directional characteristics, direction, and distance. The purpose is to obtain a discrimination device.

[Means for Solving the Problems] The sidelobe-based false image processing device according to the present invention processes image data on a concentric circle from the radiation means out of the image data of a target obtained by the radiation means with directional characteristics. equidistant video data searching means for searching and outputting the video data as equidistant video data; and signal strength calculation means for outputting video data with the strongest signal strength among the equidistant video data as true video data. , align the center of the main lobe of the directional characteristic of the radiation means with the coordinate position of the true image data, and if there is image data of equidistant image data at a position that intersects the center of the side lobe of the radiation means, use it as a side lobe. and a sidelobe artifact determination device that removes, suppresses, or identifies video data determined to be a false image by the sidelobe artifact determination device.

[Operation] In the present invention, when the equidistant image data retrieval means searches for image data located on a concentric circle from the radiation means and outputs the image data as equidistant image data, the signal strength calculation means The video data with the strongest signal strength is output to the sidelobe artifact determination means as a true video image.

Then, the sidelobe false image determining means aligns the center of the main lobe of the directional characteristic of the radiation means with the coordinate position of the true image data, and if there is image data at a position intersecting the center of the side lobe of the radiation means, it detects it. It is determined that the image is a false image due to side lobes.

Then, the sidelobe false image determining means removes, suppresses, or identifies the video data determined to be a false image by the sidelobe false image determining means and displays the video data.

[Example 1] Fig. 1 is a schematic configuration diagram of a sidelobe-based artifact processing device showing an embodiment of the present invention. (1) is a radiator (hereinafter referred to as an antenna), and a It has directional characteristics.

(2) is a transmitting/receiving unit, which has, for example, a transmitter, a receiver, a transmitting/receiving switch, etc. inside, supplies power to the antenna (1) at a predetermined timing, and transmits the radio waves reflected from the target object to the antenna (1). 1), the received radio waves are converted into video data, and the video data is output.

(3a) is an input image memory in which the video data output from the transmitter/receiver (2) is stored, and the video data is output by an address control signal (hereinafter referred to as the first address control signal) which is sequentially retrieved for each direction. It is something to do. This video data is stored in correspondence with the signal strength of the reflected wave.

(3b) is an output image memory, in which video data (hereinafter referred to as true video data) from which images due to side lobes have been removed is controlled by an address control signal (hereinafter referred to as a second control signal) from a video data output means to be described later. ) is stored, and its true video data is output to the display (4).

Note that the input image memory (3a) and the output image memory (3b) are collectively referred to as an image memory (3).

(5) is a video data importing means, which outputs a first address control signal to the input image memory (3a) to sequentially retrieve the video data stored in the input image memory (3a) for each direction, and which will be described later. An address control signal (hereinafter referred to as a third address control signal) is output to the storage means to store the video data, and when the omnidirectional video data is stored, a storage end signal indicating that the omnidirectional video data has been stored is output. This is what is output.

(6) is a storage means, which is a working area in which video data from the input image memory (3a) is sequentially stored for each direction based on the third address control signal from the video data importing means (5). , and outputs video data processed in accordance with a predetermined control signal.

(7) is a video data reading means, which reads the number and coordinate values of video data stored in the working area of the storage means (6) when the storage end signal is output from the video data importing means, and reads the number and coordinate values of the video data stored in the working area of the storage means (6). ), and output all the video data stored in the storage means (6) to the video data output means (described later) if there is no plurality of video data. It outputs an output permission signal to be output.

(8) is a distance calculation means, and a video data reading means (7
) from the coordinate values of the first coordinate value data from the antenna (1
), and outputs a circular locus (hereinafter referred to as circle data) with that distance as its radius.

(9) is a video data search means, which uses the coordinate value of the first coordinate value data outputted from the video data reading means (7) as a starting point, and searches the circle of the circle data outputted from the distance calculation means (8). A device that searches for images on the trajectory, stores the coordinate values of the image data on the circumference if there are multiple images, and outputs second coordinate value data that informs the coordinate values of the image data on the circumference. It is.

(10) is a signal strength calculation means, which calculates and stores the signal strength of the video data based on the coordinate values of the second coordinate value data output from the video data search means (9), and It outputs third coordinate value data that informs the coordinate values of video data.

(11) is the false image determination angle, and the antenna used (1
) is set by the input means (12) according to the directional characteristics of the antenna, and will be described later with reference to the drawings.

(13) is a sidelobe false image determination means, which calculates the coordinate values of the third coordinate value data output from the signal strength calculation means (10) between the center line of the main lobe of the false image determination angle and the antenna (1). ), calculate the coordinates of the intersection of the circle of the circle data calculated by the distance calculation means (8) and the center line of the side lobe, and add the signal strength calculation means (
If there is video data with a weak signal strength calculated in step 10), it is determined to be a false image, and a signal (hereinafter referred to as a false image determination signal) that informs the coordinate values of the video data determined to be a false image is output.

(14) is a sidelobe false image removing means, and video data of corresponding coordinate values stored in the storage means (6) based on the false image determination signal output from the sidelobe false image determining means (13>) It is intended to remove.

(15) is a video data output means, which outputs the video data stored in the storage means (6) every time the output permission signal is output.
It outputs an address control signal for outputting the image data to the storage means (6), and outputs a second address control signal to the output image memory (3b) to store the video data.

FIG. 2 is a diagram illustrating the directional characteristics of the antenna (1). In this case, the explanation will be based on the assumption that there are two side lobes.

In the figure, (1) is the same as in Figure 1, and (1
G) is the main lobe, (16a) is the main lobe (16
), (]7) is the first sidelobe, (17a
) is the center line of the first side lobe (17).

(18) is the second side lobe, and (18a) is the center line of the second side lobe (18).

In this figure, the angle θ1 between the center line (16a) of the main lobe (16) and the center line (17a) of the first side lobe (17) is
a) and the center line (18a) of the second side lobe (18)
It is assumed that the angle θ2 between This angle is collectively called the false image determination angle.

Furthermore, since the beam angles between the center line of the side lobe and the center line of the main lobe can be known in advance through a characteristic test or the like, they do not have to be the same.

FIG. 3 is a diagram illustrating a method for determining a false image, and is a diagram in which the image displayed on the display and the center line of the directional characteristics are overlapped.

In the figure, (1) to (L8a) are the same as those in FIG. 2 above, and (I9) is a true image obtained by the beam of the main lobe (16).

(20) is an image obtained by the beam of the first side lobe (17), which is a false image (hereinafter referred to as the first false image).
It is.

(21) is an image obtained by the beam of the second side lobe (18), which is a false image (hereinafter referred to as a second false image).
It is.

(22) has the center at the antenna (1) position and the radius (r)
This is a circle where is the distance to the coordinate (a) of the true image (■9).

(d) is the coordinate of the first false image (20), and (e) is the coordinate of the second false image (21).

This figure shows the coordinate value (a) of the true image (19) and the first point on the locus of a circle whose radius (r) is the distance to the antenna (1).
Explain that a false image appears at the coordinates (d) and (e) of the intersection of the center line (17a) of the side lobe (17) and the center line (18a) of the second side lobe (18). It is something.

Further, for example, if the side lobe is in a direction such as 90 degrees from the main lobe, a false image will be displayed at the corresponding position, but in this case, the position is at the angle θ and S2.

Therefore, since video data is stored in the input image memory (3a) corresponding to that shown in FIG. 3, for example, angles θ and S
If it is known that 2 are equal, the signal strength of the image from the main 0-b (16) is strong, the images displayed to the left and right of it correspond to the false image determination angle, and are weak images, and the antenna (
If the distances from 1) are the same, it can be determined that the image is a false image.

The operation of the sidelobe artifact processing device configured as described above will be described below using a flowchart.

FIGS. 4(a) to 4(e) are flowcharts illustrating the present invention in detail. In this case, the description will be made assuming that equations for calculating the false image determination angle (11) and the trajectory of the circle are stored in a predetermined area of the storage means (6) by the input means (12).

1. As an initial setting, registers and the like are set so that the image data is retrieved for each direction from the equation for calculating the false image determination angle (11) and the trajectory of the circle, and from the input image memory (3a) (Sl).

Next, the video data importing means (5) inputs an image memory (
3a), if video data is stored omnidirectionally for each direction from the transmitter/receiver (2), a first address control signal for storing video data in the storage means (6) for each predetermined area is sent to the input image memory. (8a), and the third address control signal is output to and stored in the storage means (6) (S3)
.

Next, it is determined whether the omnidirectional video data has been stored in the storage means (6) (S5), and if it has not been stored, control is transferred to step S3, where the omnidirectional video data is stored.

If it is determined that the omnidirectional video data has been stored in the storage means (8), the video data importing means (5) outputs a storage completion signal to the video data reading means (7).

Next, when the storage end signal 2 is output, the video data reading means (7) reads the number of video data stored in the working area of the storage means (6) and its coordinate values (S7
), it is determined whether the number is plural (S9).

In this case, since there are three pieces of video data, it is assumed that it is determined that there is a plurality of pieces of video data.

If it is determined that there are a plurality of coordinate values, first coordinate value data that informs the distance calculation means (8) of the coordinate values of the video data located at the closest position is output.

Next, when the first coordinate value data is output, the distance calculation means (8) reads one coordinate value (811) and calculates the antenna (
The distance (r) from 1) to the coordinate value is calculated and stored (811). In this case, for example, the coordinate value (a
).

Then, a trajectory of a circle centered on the antenna (1) and having a radius of distance (r) is calculated (515), and circle data indicating the trajectory of the circle is output to the video data search means (9) (917). In this case, data of a circular locus whose radius is the distance to the coordinate value (a) is reported.

Next, when the circle data is output from the distance calculation means (8), the video data search means (9) searches whether there is video data on the circumference starting from the coordinate value (a) (S19).

Then, it is determined whether there is video data (821), and if it is determined that there is video data, its coordinate values are read (S23) and stored.

In this case, it is assumed that the coordinate value (d) is retrieved and stored.

Next, determine whether the entire circumference has been searched (825), and if not, use the searched coordinate value as the starting point (527).
), the control is transferred to step 819, and the search is performed again on the circular locus.

In this case, it is assumed that the coordinate value (e) in FIG. 3 has been retrieved.

Next, if it is determined in step 825 that the entire circumference has been searched, the video data retrieval means (9) uses all the coordinate values of the retrieved video data as second coordinate value data and sends them to the signal strength calculation means (10). Output (829). In this case, the coordinate values are (a), (d), and (e) in FIG.

Then, the signal strength calculation means (10) calculates the signal strength of the video data at all coordinate values on the circumference (531) and stores it. Then, it is determined whether the calculated signal strengths of the video data are all approximately the same (838). In this case, it is assumed that only one signal has a strong signal strength.

Next, if it is determined that the signal strengths are not all the same, the signal strength calculation means (10) uses the coordinate values of the video data calculated as the strongest signal strength to the sidelobe artifact determination means (10).
13) Outputs the third coordinate value data to be notified to (83)
5).

Next, when the sidelobe false image determination means (13) is informed of the coordinate value of the strongest signal strength from the signal strength calculation means (10), the sidelobe false image determination means (13) receives the main lobe (1B) of the set false image determination angle (11). ) to the coordinates of the antenna (1) and the video data with the strongest signal strength (8
37).

Then, the circular loci calculated by the distance calculating means (8) are superimposed (S39), and the center lines (false image determination angle) of the first side lobe (17) and the second side lobe (18) are the circular locus. The coordinate values of the intersection are calculated (841).

Next, the side lobe false image determination means (13) searches to see if the coordinates of the video data searched by the video pig search means (9) are at the position of the calculated intersection 54t), and determines whether the coordinates are located at the intersection 545). , if it is determined that there is, the video data at the coordinates searched by the video data search means (9>) is determined to be a false image (S47).

Next, the sidelobe false image determination means (13) reads the coordinate values of the video data determined to be a false image from the video data search means (9), and outputs it to the sidelobe false image removal means (14) as a false image determination signal. (S49).

Then, the sidelobe artifact removal means (14) removes the video data corresponding to the coordinate values output from the sidelobe artifact determination means (13) (551), and the video data reading means (551) confirms that the artifacts have been removed. 15) Notify (853)
). Next, the video data reading means (15) removes the calculated video data and searches for the next closest video pig.
55) It is determined whether there is video data (S57).

If it is determined that there is, control is transferred to step 81.3 to execute the process described above.

Further, if the video data reading means (7) determines that there is no video data in step 859, the video data output means (15) determines that there is no video data.
) outputs an output permission signal for outputting the video data stored in the storage means (6) (S59).

Then, the video data output means (15) is transferred to the storage means (6).
An address control signal is output to the output image memory (3b) to store the stored video data (seo).

Next, it is determined whether the process is finished (581), and if the process is finished, the video data importing means (5) is set to extract the next video data (S62), and if the process is not finished, the control is started. Move to step S3.

Further, if the video data reading means (7) determines in step S9 that a plurality of video data are not stored, control is transferred to step S59 and the process described above is executed.

Further, if the video data search means (9) determines in step 821 that the video data cannot be retrieved, control is shifted to step 855 described above. Further, if it is determined in step 333 that they are of the same degree, and if it is determined in step S45 that there is no coordinate value corresponding to the position of the intersection, control is transferred to step 855.

Therefore, it becomes possible to display only the true image on the display.

In the above embodiment, the number of video data is exemplified as three, but the present invention is not limited to this, and may be a plurality of video data.

In addition, although the above embodiment describes the case where it is used for radar, it is not limited to this, and it goes without saying that it can also be used for false images caused by optical sensors with directional characteristics, sensors used in ultrasonic diagnostic equipment, etc. do not have.

Further, in the above embodiment, the false image is removed, but it may be suppressed or an identification code or the like that can be identified as a false image may be added.

Further, in the above embodiment, the circular locus was calculated by calculating the position of the nearest video data, but the video data may be located at any position on concentric circles.

[Effects of the Invention] As described above, according to the present invention, the main lobe of the directional characteristic is transmitted from the radiation means having the directional characteristic to the true video data, which is the strongest signal strength among the video data on the concentric circles. If there is video data whose signal strength is weaker than the true video data at a position that intersects the center of the side lobe of the radiation means, it is determined that it is a false image due to the side lobe,
Since the video data is removed, suppressed, or identified before being displayed, the effect of easily distinguishing between a false image and a true video is obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of a sidelobe artifact processing device showing an embodiment of the present invention, Fig. 2 is a diagram explaining the directivity characteristics of the antenna (1), and Fig. 3 is a diagram illustrating a method of detecting artifacts. The illustrative figures, FIGS. 4(a) to 4(C), are flowcharts illustrating the present invention in detail. In the figure, (1) is the antenna, (2) is the transmitter/receiver, and (
3a) is an input image memory, (3b) is an output image memory, (5) is a video data importing means, (6) is a storage means,
(7) is a video data reading means, (8) is a distance calculation means,
(9) is a video data search means, (10) is a signal strength calculation means, (11) is a false image determination angle, (13) is a sidelobe false image determination means, (14) is a sidelobe false image removal means, ( 15) is a video data output means, (16) is a main lobe, 9 (17) is a first side lobe 1. (1B) is the second side lobe. 0

Claims (1)

[Claims] (1) Equidistant image data in which image data of a target obtained by a radiation means with directional characteristics is searched for image data located on a concentric circle from the radiation means, and the image data is output as equidistant image data. a search means; a signal strength calculation means for calculating the signal strength of the equidistant video data and outputting the video data with the strongest signal strength among them as true video data; If there is image data of the equidistant image data at a position where the main lobe of the directivity characteristic of the radiation means is aligned and intersects with the center of the side lobe of the radiation means, the side lobe is determined to be a false image due to the side lobe. A false image due to a side lobe, comprising: a lobe false image determining means; and a side lobe false image determining means for removing, suppressing, or identifying video data determined to be a false image by the side lobe false image determining means. Processing equipment.