JPH0132958B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radar scan converter, and more particularly to a digital scan converter.

Conventionally, there has been a device of this type as shown in FIG. This converts radar video signals input in radial scan to raster scan TV.
This is an example of a scan converter that converts to a video signal.

In the figure, 1 is an A/D conversion section, 2 is a coordinate conversion section, 3 is a trail processing section, 4 is a display memory section, 5 is an address switching section, 6 is a D/A conversion section, and 7 is a TV readout control section. It shows. Also, for each signal, 10
1 is a radar video signal, 102 is a radar direction signal/trigger signal, 103 is a new video data signal, 104 is a write address signal, 105 is a previous video data signal, 106 is a write video data signal, 107 is a Memory address signal, 108 read data signal, 109 read address signal, 11
0 indicates a TV video signal, and 111 indicates a TV synchronization signal.

Next, the operation will be explained. Radar video signal 101 input by radial scan
is converted from an analog quantity to a digital quantity by the A/D converter 1 and inputted to the track processing part 3 as a new video data signal 103.

The track processing unit 3 performs processing to display the track of the moving target by displaying a video from several antenna scans ago (one rotation of the radar antenna is called one antenna scan). That is, the video data of pixels corresponding to the new video data 103 already stored in the display memory section 4 is read out as the previous video data signal 105, and this is attenuated by a predetermined amount, and the new video data signal is read out as the previous video data signal 105. 1
03, select the larger one and write the video.
It is output as a data signal 106. Writing video/
The data signal 106 is written into the display memory 4 consisting of memory cells in one-to-one correspondence with the pixels. Video data corresponding to a moving target is attenuated with each antenna scan by such track processing to create a track. This written video data is read out from the display memory section 4 by raster scanning,
The signal is sent to the D/A converter 6. The D/A converter 6 converts the digital amount into an analog amount, outputs it as a TV video signal 110, and displays it on a TV display device (not shown) with a track attenuated for each antenna scan. .

Memory address signal 107 for writing the write video data signal 106 into the display memory section 4
is created in the coordinate conversion section 2 by a conversion operation from polar coordinates indicated by the radar azimuth/trigger signal 102 to X, Y coordinates, passes through the address switching section 5, and is given to the display memory section 4. A memory address signal 107 for reading from the display memory section 4 by raster scan is generated by the TV readout control section 7, passed through the address switching section 5, and given to the display memory section 4. In addition to the read address signal 109, the TV read control section 7 outputs a TV synchronization signal 111.

Note that the display memory section 4 has a control memory that corresponds to each pixel on a one-to-one basis. Depending on the pixel, the sweep may hit many times during one antenna scan, but if you apply wake processing to that pixel each time, the sweep will hit the pixel only once during one antenna scan. Therefore, the attenuation during one antenna scan becomes large, resulting in uneven brightness. The control memory is intended to avoid this, and stores information on whether or not a sweep was applied during one antenna scan.

Writing or reading of video data signals to or from the display memory section 4 is performed in a time-division manner. The address switching unit 5 switches the write address signal 104 output from the coordinate conversion unit 2 and the read address signal 109 output from the TV read control unit 7, and displays the memory address 107 corresponding to writing or reading in the memory unit. It is given to 4.

Since the conventional device was configured as described above, when there were many pixels, there was a problem that the radar sweep could not hit all the pixels, as will be explained below. FIG. 2 is a diagram illustrating the positional relationship between radar sweep and pixels in a scan converter. In the figure, each cell of the grid indicates a pixel, 201 is a radar sweep line, and the black mark ●/202 shown on the radar sweep line 201 is a sampling point for converting the radar video signal from an analog quantity to a digital quantity. It is. Pixels that are not hit by this sampling point 202 (hereinafter referred to as "pixels that are not hit by sweep")
A pixel 204 (hereinafter referred to as a "sweep hit pixel") 203 that is hit by the sampling point 202 indicated by diagonal lines is generated.
The smaller the pixel and the greater the number of pixels, the more "pixels that are not swept" occur. Furthermore, the smaller the number of sweeps within one rotation of the radar, the more "pixels that are not hit by the sweep" occur.

In the above conventional device, the "pixel that is swept"
The contents of the display memory section 4 are updated only for pixels that are not swept, but the contents of the display memory section 4 are not updated for "pixels that are not swept," and the state of the initial value is maintained. Therefore, when the initial state is zero, "pixels that are not swept" are always displayed in black.
``Pixels that cannot be swept'' often occur in locations far from the radar site and are present in a striped pattern, causing a black striped pattern on radar echo displays such as clouds, making the display difficult to see. Further, there was a problem in that there was a difference in brightness between radar echoes of the same shape in areas where many "pixels that were not swept" occurred and areas where they did not occur. Furthermore, if the initial state was not zero, a bright spot would be displayed in an area where no radar echo actually existed, and there was a possibility that the area would be mistakenly recognized as having a radar echo.

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional technology, and it interpolates "pixels that were not swept" using video data of nearby "pixels that were swept". , display memory section 4
By ensuring that the contents of the image are updated, defects caused by pixels that are not swept can be removed, and a digital scan converter with high visibility and high resolution can be provided. The purpose is

An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 shows an overall system diagram of an embodiment of the present invention. Further, detailed system diagram examples of the data compression section 8, the track processing section 3, and the interpolation processing section 4 in this embodiment are shown in FIGS. 4, 5, and 6, respectively. In the figures, the same reference numerals indicate the same or corresponding parts.

In FIG. 3, 8 indicates a data compression section, and 9 indicates an interpolation processing section. Also, 112 is a new video data
113 is a video data block signal, 114 is a write video data block signal, 115 is a previous video data block signal, and 116 is a radar coordinate signal.

The main difference between the embodiment of the present invention shown in FIG. 3 and the conventional method is that after converting the radar video signal 101 into a digital quantity, the data compression section 8 converts the video data signal (hereinafter referred to as (hereinafter referred to as a video data block), the data is compressed and processed in parallel, and the trail processing and interpolation processing are performed by the trail processing section 3 and the interpolation processing section 9, respectively, and then written to the display memory section 4. At the point.

Next, the operation will be explained. The input radar video is converted from an analog quantity to a digital quantity in the A/D converter 1 and is converted into a new video data signal 103.
The video data signal for several pixels is outputted to the data compression unit 8 as a block pixel, and is processed here as a block pixel.

The relationship between this pixel and block pixels is shown in FIG. Each cell 205 partitioned by a dotted line is a pixel, and the pixels partitioned by a solid line are block pixels. Reference numerals 201 to 204 in the figure indicate the same parts as in FIG. 2. In this way, the 16 pixels are treated as one block pixel, and the trail processing and interpolation processing are performed for each block pixel, and the data compression section 8 performs the process of combining the video data into the block pixels. or,
The data compression unit 8 creates a hit data signal 117 indicating the hit pixel position of which pixel among the 16 pixels in the block pixel was hit by the sweep as data necessary for interpolation processing, and outputs it to the interpolation processing unit 9. Ru.

Next, the process of combining video data for each block pixel in the data compression section 8 will be explained. The data compression section 8 has a buffer memory in which video data for the maximum block of pixels covered by one sweep can be stored, and is designed to process video data block by block. When the input new video data signal 103 starts hitting a certain block pixel, the video data block in the buffer memory corresponding to this block pixel is reset, and the video data corresponding to the new video data signal 103 is reset. -Write a new video data signal 103 to the pixel portion of the data block. after that,
Until the sweep no longer hits this block pixel,
During several sweeps, each time the sweep hits this block pixel, the corresponding video data in the buffer memory is
New video data signal 1 is applied to the pixel part within the block.
03 is stored. In areas corresponding to the center of the radar site, the same pixel may be swept several times; in this case, the contents of the buffer memory and the new video data signal 103 are compared and the larger one is stored in the buffer memory. Write. The video data block signal 113 stored in this way is
When the sweep no longer hits that block, a new video data block signal 11 is sent to the wake processing unit 3.
Output as 2.

Along with the above processing, the data compression unit 8
A data signal 117 is created and output to the interpolation processing section 9. That is, the data compression section 8 has a buffer memory for storing the video data block signal 113 as well as a buffer memory of 16 bits per block for storing the corresponding hit data signal 117. When the sweep starts hitting a particular block pixel, the corresponding hit data signal 117 stored in the buffer memory is reset, and each time the sweep hits a block pixel, the hit data signal 117 stored in the corresponding buffer memory is reset.・Set the data bit to “1”. When the sweep no longer hits the block pixel, 11716 bits of the hit data signal are sent to the interpolation processor 9. For example, FIG. 8 shows the hit data signals 117 for the pixel 204 hit by the shaded sweep in FIG. 7 and the pixel 203 hit by the other sweeps. In the figure, 206 indicates the hit data of pixels that are not swept, and 207 indicates the hit data of pixels that are swept. These hit data are output in units of 16 bits corresponding to block pixels partitioned by solid lines.

Next, the data compression section 8 will be explained in detail.
In FIG. 4, 10 is a video comparison section, 11 is a buffer memory section, 12 is an address comparison section, and 13 is an address memory section. Also, 118 is a pixel address signal within a block, and 119 is a block address.
X _B signal, 120 is block address Y _B signal,
121 is video data. Block output timing signal, 122 is {|X _B +Y _B |-|X _BM |} signal, 123 is |X _B +Y _B |} signal, 124 is |X _B
｜Indicates a signal.

|X _B | and |Y _B | independently increase monotonically as 1, 2, 3, etc. with the start of the sweep. FIG. 10 is an example showing the relationship between block addresses X _B and Y _B and sweep. In Figure 10, the small squares separated by a grid indicate block pixels, and these block pixels
Addresses X _B and Y _B are determined according to the distance from the sweep origin 301 |X _B |=1, 2, 3..., Y _B = 1, 2, 3
It is stipulated that... 302, 303, and 304 show part of the sweep, which sweeps outward from the sweep origin. That is, the radar sweep 302 sweeps outward from the sweep origin as indicated by the arrow, and ends the sweep when a predetermined final distance is reached. When the radar sweep 302 ends, the next radar sweep 303 starts from the sweep origin. radar sweep 30
3, the next radar sweep 304 begins, and the sweeps are successively performed one after another, usually while changing the angle in a clockwise direction. Radar sweep 303 successively blocks pixels (1, 1), (1, 2), (1,
3), (1, 4), (2, 4), etc., the radar sweep 304 successively sweeps the block pixels (1, 1),
(1, 2), (1, 3), (2, 3), (2, 4),...
corresponds to When the sweep reaches 304, the block pixels (1, 4) are no longer hit, and the block pixels (2, 3) are newly hit.

Address comparison section 12 and address memory section 13
is a part for detecting block pixels which are no longer being swept, among the block pixels stored in the buffer memory section 11 and undergoing data compression processing.
The buffer memory section 11 stores one sweep's worth of video data blocks corresponding to the block pixels being swept, and the hit data corresponding thereto. The video comparison section 10 includes a new video
This section compares the data signal 103 with the corresponding video data from the buffer memory section 11 and outputs the larger one to the buffer memory section 11.

A radar coordinate signal 116 whose origin is the radar site of the input new video data signal 103 is input. Block addresses X _B and Y _B are obtained from the radar coordinate signal, and are calculated and compared with the block address information during data compression processing to detect whether the sweep hits the block pixel during data compression processing. . If the sweep hits the block pixel being processed, the new radar video 103 and the video stored in the buffer memory section 11 are
The video comparison section 10 selects the larger one and writes it into the buffer memory section 11. At the same time, 1 is written to the corresponding bit of the human data. If the block pixel being processed has not been hit, it means that the sweep has started hitting a new block pixel, so the video data block output timing signal 121 is output, and the corresponding video data block pixel in the buffer memory 11 is output. Block signal 113 and hit data signal 117
Output.

The following method is used to detect whether the sweep hits a block pixel during data compression processing. That is, the sum of the absolute values of the coordinates of the block address signals X _B and Y _B {|X _B |+|Y _B |} will never be the same value if the quadrants of adjacent block pixels are the same. This fact is used to determine whether the sweep has hit a block pixel. Block
Create {|X _B |+|Y _B |} from the address signals X _B and Y _B , and create the address of the address memory section 13 {|
When writing data |X _B | to X _B |+|Y _B |} and determining whether the next sweep hits this block pixel, new data {|X _B +Y _B |} is created. ,
Contents of the address memory section at this address | X _B
|(Assuming this was written in memory |
Let's call it X _BM ｜. ) is read out {｜X _B +Y _B
Calculate |−|X _BM |}. If it hits the previous block pixel, |X _B | and |X _BM | are equal, so {|X _B +Y _B |−|X _BM ||}=|Y _B |. If it is not true, this equation does not hold. Therefore, {|X _B +Y _B |−|X _BM |} and |Y _B |
are compared by the address comparator 12, and if they are not equal, it is assumed that the sweep no longer hits the block pixel being processed, and a video data block output timing signal 121 is output. Also, if the quadrants of adjacent block addresses are different, X _B ,
The sign of Y _B is stored in the address memory section 13, and this is compared with the signs of X _B and Y _B of the next sweep. If they are different, it means that the pixel no longer hits the block pixel being processed. To detect.

The radar coordinate signal 116 of the input video data signal 103 changes with time after the start of the sweep, and its block addresses X _B ,
_YB will also change. By processing the block address corresponding to the radar coordinate signal 116 each time, it is possible to sequentially process all the block pixels for one sweep.

As described above, the input new video data signal 103 is compressed for each block pixel in the data compression section, and the video data block signal 103 is compressed for each block pixel.
13 and is output to the track processing section 9. It also creates a human data signal 117 and outputs it to the interpolation processing section 9.

The track processing section 3 attenuates the previous video data block signal 115 from which the video data block already stored in the display memory section 4 has been read, and combines this with the new video data block signal 11.
2 and outputs the larger one to the interpolation processing section 9.
Since the video information already written in the display memory section 4 is rewritten in this way, the track of the moving target is displayed. The time of the wake, i.e. the accumulation time, is determined by the previous video data block signal 115.
Depends on the degree of attenuation applied to Therefore, the track time is controlled by controlling the degree of this attenuation.

A detailed system diagram of the track processing section 3 is shown in FIG.
In the figure, 14 is a video comparison section, and 15 is an attenuation section. The previous video data block signal 113, which has already been written in the display memory section 4, is transferred to the attenuation section 15.
The comparator 14 compares the signal with the new video data block signal 112 and outputs the larger one as the video data block signal 113.

In the interpolation processing section 9, based on the hit data signal 117 created by the data compression section 8, pixels that were not swept are interpolated with neighboring pixels that were swept. For example, when the human data shown in FIG. 8 is sent to the interpolation processing section 9,
FIG. 9 shows an interpolation method for pixels that are not swept. In the figure, 208 indicates a pixel used for interpolation, and 209 indicates a pixel to be interpolated. Video data of a pixel whose hit data is "1" that has been swept is converted into video data of a pixel whose hit data is "1". In the case of FIG. 9, interpolation is performed in the X-axis direction, but it is performed in a direction where the number of successive pixels that are not swept is small. FIG. 6 shows a detailed system diagram of the interpolation processing section 9. In the figure, 16 indicates an interpolation section, 17 indicates an interpolation direction detection section, and 125 indicates an interpolation direction signal. The interpolation unit 16 is capable of interpolating in several types of interpolation directions such as the X-axis direction and the Y-axis direction, and determines the interpolation direction using the radar coordinate signals 116 to 17 and determines the interpolation direction using the interpolation direction signal 125. Interpolate by direction.

The interpolated write video data block signal is written into the display memory section 4. The video data written in the display memory section 4 is read out by raster scanning, converted to D/A, and displayed on the TV.
It is output as a video signal 110.

In the above embodiment, 16 pixels constitute one block, but the effect remains the same as long as the number of block pixels is 2 or more. Further, although the interpolation processing section 9 is connected after the wake processing section 3, the same effect can be obtained even if the interpolation processing section 9 is connected before the wake processing section 3.

As described above, according to the present invention, since the video data is updated by performing track processing and interpolation processing in parallel for each block, there are black spots and display objects caused by pixels that are not swept within the display object. This eliminates the need for display in areas that are not intended for display, improving image quality and providing high visibility.In addition, since multiple pixels are grouped into block pixels, the capacity is large, and the display memory, which is constantly read out for display, is This reduction in accesses enables high-speed processing of input data, which has the effect of making high-resolution digital scan converters possible.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional digital scan converter, Fig. 2 is an explanatory diagram showing the positional relationship between radar sweep and pixels in the digital scan converter, and Fig. 3 is a system diagram of an embodiment of the present invention. , FIG. 4, FIG. 5, and FIG. 6 are detailed system diagrams of the data compression section 8, the track processing section 3, and the interpolation processing section 9 in FIG. 3, respectively. Figure 7 is a diagram showing the relationship between block pixels and pixels, Figure 8 is a diagram showing human data using Figure 7 as an example, and Figure 9 is a diagram showing the relationship between block pixels and pixels.
The figure shows an interpolation method corresponding to Figure 8, and Figure 10.
The figure is a relationship diagram showing the relationship between block addresses and sweeps. In the figure, 3 is a track processing section, 4 is a display memory section, 8 is a data compression section, 9 is an interpolation processing section, 101
1 is a radar video signal, 110 is a TV video signal, 112 is a video data block signal, 1
17 is a human data signal. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1 A pixel consisting of grid-like cells in a display unit is set at the sample position of a radar signal obtained by radar sweep, and the radar signal by radial scan is converted into a television radar signal by raster scan, which is displayed on the display unit. It has a buffer memory that stores radar signals at each pixel within a predetermined block pixel, with a plurality of adjacent pixels as block pixels, and when a radar sweep hits a predetermined block pixel, the block pixel is Accumulate the radar signal in the buffer memory mentioned above,
When the radar sweep no longer hits a predetermined block pixel, it outputs the radar block signal stored in the buffer memory and checks whether each pixel in the predetermined block pixel corresponds to the sample position. a data compression unit that outputs a hit data signal shown in the figure; a track processing unit that compares a radar block signal from the data compression unit with a radar block signal from a predetermined block pixel in a preceding radar sweep and outputs the larger one; an interpolation processing unit that interpolates pixels to which the sample position does not correspond in a predetermined block pixel based on the human data signal using neighboring pixels to which the sample position corresponds; 1. A digital scan converter comprising a display memory section for storing radar block signals, and reading out radar signals interpolated for each block pixel by raster scan.