JPH057664B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a display circuit for displaying a video signal in a primary radar device on a radar display device.

(Prior Art) Conventionally, this type of radar image display method has been a method in which a signal received and processed by a radar receiver is sent as is to a display device, and the intensity of the video signal displayed on the display device is controlled. Ta. That is, the intensity of the video signal is uniformly controlled for both the normal video signal and the MTI video signal, regardless of whether they are inside or outside the clutter area.

(Problem to be Solved by the Invention) When observing a radar image, for example, in the case of a normal image, the image gain is increased to the extent that noise is slightly visible outside the clutter area, and the target brightness is maintained, while within the clutter area, the clutter signal itself is If you want to lower the video gain because the level of MTI is strong,
In the case of images, there are cases where it is desired to increase the image gain and increase the brightness of a small target for observation in a clutter area so that some residual clutter can be seen. That is, for normal video signals as well,
For MTI video signals as well, if the video gain is controlled independently inside and outside the clutter area, an easily observable video may be obtained.

However, in the above-mentioned conventional technology, since the video gain is controlled by a single gain control circuit regardless of whether it is inside or outside the clutter area, there is a problem that the target video signal may become difficult to observe.

In view of the above-mentioned conventional problems, an object of the present invention is to
The video gain can be adjusted independently for both normal video and MTI video inside the clutter area and outside the clutter area, and at the same time, it is possible to observe the normal video and MTI video in a superimposed state outside the clutter area. The present invention aims to provide a radar image display circuit that allows target images to be observed more reliably.

(Means for Solving the Problems) The present invention has the following means configuration to achieve the above object. That is, the radar image display circuit of the present invention includes an intra-clutter area gain control circuit that receives a clutter gate signal indicating that the video signal is within the clutter area and outputs a gain control signal for controlling the gain for a video signal within the clutter area; a first variable gain video circuit that receives a video signal and the gain control signal to control the output level of the normal video signal in the clutter area;
a second variable gain video circuit for controlling the output level of the MTI video signal; a first video selection for receiving the output signal of the first variable gain video circuit and the clutter gate signal to extract a video signal outside the clutter region; a second video selection circuit that receives the output signal of the second variable gain video circuit and the clutter gate signal and extracts a video signal outside the clutter area; a first video adder that receives the output signals of the two video selection circuits, adds them together, and outputs the results;
A radar image display circuit comprising: a second video adder that receives the output signal of the second variable gain video circuit and the output signal of the first video selection circuit, adds them together, and outputs the sum; be.

(Function) Hereinafter, the function of the radar image display circuit of the present invention having the above means configuration will be explained.

The clutter area gain control circuit configured as described above receives the clutter gate signal and transmits a gain control signal to the first and second variable gain video circuits for performing gain control only on the video signal within the clutter area among the input video signals. is being sent to. The gain control itself may be automatic or manual.

Since a normal video signal is input to the first variable gain video circuit, its output is a normal video signal in which the clutter video level in the clutter area is controlled.

Similarly, the second variable gain video circuit
Since the MTI video signal is input, the output is an MTI video signal in which the clutter in the clutter area is eliminated and the video level is controlled.

On the other hand, the first and second video selection circuits receive the normal video or MTI video from the first and second variable gain circuits, respectively, and also receive the clutter gate signal, and select the video signals outside the clutter area from among the input video signals. Extract.

That is, the first video selection circuit extracts the video signal outside the clutter area from the normal video signal, and the second video selection circuit extracts the video signal outside the clutter area from the MTI video signal.

The normal video output signal of the first variable gain video circuit is also input to the first video adder;
The first video adder receives the motion and the MTI video signal from the second video selection circuit, and adds both signals. Therefore, the output signal of the first video adder is a normal clutter video signal whose level can be adjusted within the clutter area, and a signal obtained by combining the normal video signal and the MTI video signal outside the clutter area.

Further, the output signal of the second video adder is an MTI clutter remaining video signal whose level can be adjusted within the clutter area, and a signal obtained by combining the MTI video signal and the normal video signal outside the clutter area. Level adjustment of the video signal outside the clutter area may be performed by the first and second video selection circuits, or by the first and second video adders. In any case, since the video signal level within the clutter area can be adjusted independently, the output of the video adder can be adjusted to the optimum level.

(Example) Hereinafter, an example of the radar image display circuit of the present invention will be described based on the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of a radar image display circuit according to the present invention.

In FIG. 1, each of a normal video signal 1 and an MTI video signal 15 sent out from a receiver is sent to a variable gain video circuit 2 by a clutter gate signal 8 in which a clutter area is determined by the receiver.
Gain adjustment is performed only in the clutter region.

The rate of gain adjustment is determined by the gain control signals 9 and 16 sent out by the gain control circuit 10 in the clutter region.
is set according to each video signal.

Video signals 3 and 7, whose gain is controlled only in the clutter region, are divided into two parts by a video distributor 4 and added together by a video adder 6, and then sent to a radar display device 14 and displayed on a display screen. Ru.

Next, each video system will be explained in detail.

Normal video signal 1 sent from receiver
is input to the variable gain video circuit 2, and only the video signal in the clutter area is gain controlled by the gain control signal 9 sent from the clutter area gain control circuit 10, and the gain-controlled video signal 3 is sent to the video distributor 4. One video signal 5 is added to a video adder 6. The other video signal 5 is applied to the video selection circuit 12, and only the video signal 19 outside the clutter area is extracted by the area selection signal 11 sent from the clutter area gain control circuit 10, and the video signal 19 outside the clutter area is extracted. The signal 20 mixed with the MTI video signal 18 is displayed on the display screen of the display device 14.

Also, the MTI video signal 1 sent from the receiver
5 is input to the variable gain video circuit 2, and only the video signal in the clutter area is gain controlled by the gain control signal 16 sent from the clutter area gain control circuit 10, and the gain-controlled video signal 17 is sent to the video distributor 4. One of the video signals 18 is added to the video adder 6.

Further, the other video signal 18 is applied to the video selection circuit 12, and the clutter area gain control circuit 1
Only the video signal 13 outside the clutter area is extracted by the area selection signal 11 sent from 0, and is added to the normal video system video adder 6, and is displayed on the display screen of the display device 14 as a signal 7 mixed with the normal video signal 5. displayed above.

Note that in the above embodiment, the video selection circuit 12
does not directly receive the clutter gate signal but receives the area selection signal 11 from the clutter area gain control circuit 10. This is because a partial circuit that can be shared by the gain control circuit and the video selection circuit is provided in the clutter area gain control circuit 10. Both the gain control within the clutter area and the selection of the video outside the clutter area are operations that are made possible by receiving the clutter gate signal. In addition, the video selection circuit 1
2 includes first and second video selection circuits referred to in the means configuration.

Figure 2 is a diagram showing an example of PPI display on a display device, where Figure a shows a clutter area, Figure b shows an example of display using normal signal system signals, and Figure c
FIG. 2 is a diagram showing an example of display using the MTI signal system. In Figures b and c, normal images and MTI images appear superimposed outside the clutter area.

(Effects of the Invention) As explained above, the radar image display circuit of the present invention is capable of separately controlling the level of the video signal in the clutter area for each of the normal video signal and the MTI video signal. The brightness and intensity can be adjusted to enable more accurate target observation than before, both within the Kuratsuta region and outside the Kuratsuta region.For areas outside the Kuratsuta region, images from normal video and MTI video are overlapped. This has the advantage that the target image can be seen more reliably since it can be observed in the same state.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the radar video display circuit of the present invention, and FIG. 2 is a diagram showing an example of PPI display when the radar video display circuit of the present invention is used. 1... Normal video signal, 2... Variable gain video circuit, 4... Video distributor, 6... Video adder, 8... Clutter gate signal, 10... Clutter area gain control circuit, 12... Video selection Circuit, 14...Display device, 15...MTI video signal.

Claims (1)

[Claims] 1 a clutter area gain control circuit that receives a clutter gate signal indicating that the clutter area is within the clutter area and outputs a gain control signal for controlling the gain for the video signal within the clutter area; The first control unit controls the output level of the normal video signal within the clutter area.
a variable gain video circuit; receiving the MTI video signal and the gain control signal;
a second variable gain video circuit that controls the output level of the video signal; a first video selection circuit that receives the output signal of the first variable gain video circuit and the clutter gate signal and extracts the video signal outside the clutter area; a second video selection circuit that receives the output signal of the second variable gain video circuit and the clutter gate signal and extracts a video signal outside the clutter area; a first video adder that receives the output signals of the second variable gain video circuit and the output signals of the first video selection circuit and adds them; A radar image display circuit comprising: a second video adder for outputting a video signal;