JPS58178277A - Video signal processing system for radar - Google Patents

Abstract

PURPOSE:To obtain a video signal of one system of radar excluding false image or shade region by taking correlation between two video signals or selecting either thereof from monitoring regions overlapping other with two radars. CONSTITUTION:A radar 1 and a radar 2 search within monitor regions Q1 and Q2 coinciding the bearings of antennas and transmit video signals (a1) and (a2) to a selection/correlation circuit 5 and a scan conversion circuit 3. Among signals (a2), only signals belonging with the recording range A are memorized into the associated image memory according to the PPI scanning of the radar 2 and read out according to the PPI scanning of the radar 1 by a trigger signal (b1) and an antenna angle CI to be sent to the selection/correlation circuit 5 as video signal (d). A part in the shade region R due to one obstacle in the radar selects the contents of a video signal (d) and a part in the frequent false image occurrence region S takes correlation between the contents of the signal (a1) and the signal (d) while other parts are synthesized into a video signal (f) leaving the signal (a1) as intact and sent out to an output terminal 6.

Description

[Detailed description of the invention] The present invention relates to a video signal processing method of DA.

In systems that monitor the sea using radar, if there are dog-shaped obstacles such as islands or bridges within the monitoring range, false images are generated based on multiple reflections between these obstacles and targets such as ships. There are areas where the target cannot be detected (areas where false images occur frequently) and areas where the target cannot be detected (shadow areas) because radar waves do not reach behind obstacles. In such cases, conventionally, another radar is installed in a position where it can irradiate the false image-prone area and the shadow area from other directions, and the video output of this radar and the video output of other radars are directly connected artificially. After the images were compared or processed by a computer, they were compared with each other by a computer to determine whether or not they were false images, and the image and sound of both radars were displayed separately or by switching.

This makes it complicated and inconvenient to judge false images and observe radar images.

In order to eliminate the above-mentioned conventional drawbacks, the present invention provides a monitoring area in which two radars installed at two different locations synergize with each other, and temporarily stores the video signal of one radar.
The stored contents are read out according to the scanning signal of the other radar, and the correlation between the video signal of the other radar and the read video signal of the one radar is calculated for the area where false images occur frequently in the monitoring area. The purpose of this is to synthesize a video of one system of radar from which all artifacts and shadow areas have been removed. It's about getting a signal. The drawings will be described in detail below.

FIG. 1 is a block diagram showing one embodiment of the present invention.
is the first radar, 2 is the second radar, 3 is the scan conversion circuit, 4 is the area signal generation circuit, 5 is the selection/correlation circuit, 6 is the output terminal for the synthesized video signal, 7 and 8 are the above-mentioned, respectively. This is an output terminal for the trigger signal and antenna angle signal of the radar 1.

The radar 1 emits pulse radio waves of a constant period from a horizontally rotating antenna (not shown), receives and detects all reflected signals from the target again by the above antenna, and performs P P I scanning (R
-θ scanning) is output to the selection/correlation circuit 5 as a video signal a1, and the trigger signal b1 is sent to the scan conversion circuit 3, area signal generation circuit 4, and output terminal 7, and the antenna angle signal elk radar 2, The signal is sent to the scan conversion circuit 3, area signal generation circuit 4, and output terminal 8. Radar 2 is installed at a different point from Radar 1, where it can illuminate areas where false images occur frequently and shadow areas within Radar 1's monitoring area from a direction different from that of Radar 1, and its configuration is almost the same as Radar 1. In response to the antenna angle signal cli of the radar 1, the rotation direction of the antenna is controlled so as to always match the direction of the antenna of the radar 1. The video signal a2, trigger signal b2, and antenna angle signal c2 of the radar 2 are sent to a scan conversion circuit 3.

The scan conversion circuit 3 converts the video signal a2 of the radar 2 into the radar 1.
The video signal a1 is converted into a video signal d having the same coordinate axes and sent to the selection/correlation circuit 5, and is realized, for example, by a scan conversion type storage tube. Further, the area signal generation circuit 4 generates a signal from the radar 1 based on the trigger signal bl and the antenna angle signal c1.
A gate pulse-like area signal e''f) corresponding to a predetermined false image frequent area or shadow area within the monitoring range of is generated in accordance with the scanning of the radar 1 and is sent to the selected φ correlation circuit 5. The selection/correlation circuit 5 receives the video signal a1
, the video signal d, and all the area signals e mentioned above are combined and sent to the output terminal 6.

Next, the operation of the above device will be explained using FIG. 2.

Figure 2 shows the positional relationship between radar 1 and radar 2.
In the figure, PL and P2 are the installation points of radar 1 and radar 2,
Ql and Q2 are the respective monitoring areas of radar 1 and radar 2, Q3 is an area that is the combination of the monitoring area Ql and Q2, R is a shadow area due to an obstacle (not shown) on the radar l side, and S is a region where false images occur frequently Area A is the recording range of the image memory of the scan conversion circuit 3 within the area Q3. Radar 1 and radar 2 search within each monitoring area Ql and Q2 with their antennas aligned in the same direction, and select and correlate video signals a1+a2, respectively.
and sends it to the scan conversion circuit 3. Of the video signal a2 sent to the scan conversion circuit 3v, only the signal belonging to the recording range A is stored in the image memory (in the scan conversion type storage tube) according to the trigger signal b2 and the antenna angle signal c2. screen). The video signal stored in the image memory is determined by the I]P of the radar 1 from the trigger signal b1 and the antenna angle signal CIK.
The selection/correlation circuit 5 reads out the video signal d according to I scanning and synchronizes it with the video signal a1 on the same coordinate axis.
will be sent to. The selection/correlation circuit 5 selects the content of the video signal d for the portion of the shadow area 1t according to the area signal e, correlates the content of the video signal a1 and the video signal d for the portion of the artifact-prone area S, and selects the content of the video signal d for the portion of the shadow area 1t. is combined into a video signal f, which has the contents of the video signal a1 as is, and is sent to the output terminal 6.

Therefore, according to the above embodiment, the target in the shadow region R that cannot be detected by the radar 1 is included, and the false image frequent region St/bump is detected by both radars. A video signal is obtained from which false images due to multiple reflections that occur at different positions are removed, and since the video signal is obtained as a signal by I) P I scanning of radar 1, the image display in the case of a single radar is This enables a display similar to that shown in the figure, making it easy to observe radar images.

In the above embodiment, the antenna rotation of the radar 2 is made to be in the same direction as the antenna of all the radars 1, but this is not necessarily necessary. However, if the radar 2 is tracked so that it is facing the same direction, the video signal d of the radar 2 read out by the scan conversion circuit 3 every time the radar 1's antenna rotates will be the one obtained when the radar 2's antenna rotates in the same direction. Accurate observation is possible when observing the movement of signals on the image plane. In addition, the composite video signal f of this embodiment can be shuffled, digitized, and input into a computer for data processing such as target tracking processing, and in the case of two radars as in the conventional case, two systems of data processing/systems can be used. Unlike the previous system, the required processing can be performed using only one data processing system.

In addition, when performing such data processing, more accurate data processing can be achieved by rotating the antenna of radar 2 to follow the antenna of radar 1 as in the above embodiment.

Further, in the above embodiment, only the area within the range A is stored in the image memory of the scan conversion circuit 3, but the area Q3, which is the set type, is stored in the image memory of the scan conversion circuit 3.
It may be possible to remember everything. Discarded radar 2
The monitoring area Q2 may be small as long as it covers areas R and S.

As explained above, according to the present invention, two radars installed at two different locations provide monitoring areas that are arranged in a similar pattern, the video signal sound of one of the radars is temporarily stored, and the stored contents are all the same as those of the other radar. The video signal of the other radar is read out according to the scanning signal of the radar, and the video signal of one radar read out in the above is correlated with the area where false images occur frequently in the monitoring area. As for the area, it is synthesized by selecting and removing only the video signal that is not visible, so the shadow area caused by the obstacle is removed, and the image is synthesized based on multiple reflections between the obstacle and a target such as a ship. One system of video signals from which artifacts have been removed can be obtained, displayed on one video display, and one system of data processing j-! f! This has the advantage that it can be input directly into the system, facilitating monitoring and tracking of targets within the monitoring area.

Therefore, it is extremely effective when applied to seawater monitoring systems, especially in areas with island ravines and bridges.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a block diagram of a radar video signal synthesis device to which the method of the present invention is applied, and FIG. 2 is an explanatory diagram showing the positional relationship between radar 1 and radar 2. It is. ■ First radar, 2... Second radar, 3 - Scan conversion circuit, 4... Area signal generation circuit, 5... Selection/correlation circuit, al... Video signal of first radar, a2・
... video signal of the second radar, f... composite video signal, PI... installation point of the first radar, P2 installation point of the second radar, Ql - monitoring area of the first radar, Q
2...Monitoring area of the second radar, Q3...Monitoring area that is a combination of the first radar and the second radar. Patent Applicant: Oki Electric Industry Co., Ltd. Agent Patent Attorney Yoshi 1) Written Amendment to Filial Procedures 1
(Issue) August 1, 1981 Kazuo Wakasugi, Commissioner of the Japan Patent Office 1 Display of the case 1988 Patent Commissioner No. 060598 2 Name of the invention Radar video signal processing method 8 Relationship with the person who makes the correction Patent pile -Address 1-7-12 Toranomon, Minato-ku, Tokyo Name (
02G) Oki Electric Industry Co., Ltd. Representative - Hon Minami Akio 4 Representative 105 Den (03)! 408-9866
Address Okana Building 1, 2-7-9 Toranomon, Minato-ku, Tokyo "Claims and Detailed Explanation of the Invention Column in the Specification" Contents of Amendment 6 Attached Excerpt Contents of Amendment 6 ( 1) Amend the claims as shown in the attached sheet. (2) "On page 2, line 18 and on page 8, line 14 of the specification:
The contents are respectively corrected as 1 video signal. (3) The lines from line 2 on page 3 of the specification to line 6 on the same page [ ] are amended as follows. The purpose of this is to correlate the predetermined partial areas in the description or select one of the video signals, and then combine them into a single video signal.The purpose of this is to eliminate artifacts and shadows. One system of radar vision with areas etc. removed (4
) Add ``partial area, for example'' between ``ta'' and ``false'' on page 5, line 1 of the specification. (5) Add "(matching correlation)" between "seki" and "-wo" on page 6, line 14 of the specification. (6) The text from page 8, line 5 to line 10 of the same page is amended as follows. In addition, in the second embodiment, a region with many false images and a shadow region are taken up as partial regions, but in addition to these, regions with a large amount of sea surface reflection, regions with weak signal strength, etc. can be considered, and the present invention can also be applied to these partial regions. target detection accuracy can be improved. Regarding the lunar IJ, sea surface reflections occur at different locations depending on the direction of the radar radio waves, so it is possible to completely reduce this by taking a matching correlation of two video signals from areas with a lot of sea surface reflections (2). In the area, the target signal level can be increased by taking the additive correlation between the two video signals. (7) Page 8 of Book A] From line 8 to line 1 of the ninth page Correct as shown below. Correct the correlation for the specified partial area. Or, if there is an error in selecting one of the video signals,
Since it is combined into a single video signal, shadow areas caused by obstacles are removed, a monitoring area is created in which two radars installed at two different locations overlap, and the video signal from one of the radars is temporarily stored. , the stored video signal is read out according to the scanning signal of the other radar, and the video signal of the other radar and the read video signal of the one radar are read out for a predetermined partial area within the monitoring area. A radar video signal processing method characterized by compositing. 3

Claims (1)

[Claims] A synergistic monitoring area is provided by two radars installed at two different points, the video signal of one radar is temporarily stored, the stored contents are read out using the scanning signal Q of the other radar, and the other radar is read out according to the scanning signal Q of the other radar. By correlating the video signal of the radar with the read video signal of one of the radars for the area where false images occur in the monitoring area, and for the shadow area, only one of the video signals is calculated. A radar video signal processing method characterized by combining by selecting and removing.