JPS6184573A - Radar scanning conversion system - Google Patents

Abstract

PURPOSE:To prevent deterioration in the picture quantity of a radar video due to the absence of a picture element by compensating the absence of the picture element during conversion by using a conversion gap coordinate memory as to the radar scanning conversion system which converts a polar coordinate display into an orthogonal coordinate display. CONSTITUTION:An analog radar signal from a radar receiver is digitized by an A/D conversion part 100 and written in a buffer memory 101. An XY address generation part 103 converts polar coordinate indicated by a polar coordinate azimuth distance address generation part 102 into an address position on an orthogonal coordinate system and stores the signal of the memory 101 in a video memory 104 having orthogonal coordinate addresses. A picture-element absence memory 105 is provided with a storage circuit stored with the orthogonal coordinate address of a conversion gap generated during the conversion from the polar coordinate system to the orthogonal coordinate system. Then, this memory 105 is instructed to output said conversion gap address to an address generation part 103 in a next step when an address after conversion is nearby the conversion gap (picture element absence).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of industrial application) The present invention provides PPI (Pla...
nPo5ition Indication) Scanning Method This relates to a method for improving image quality deterioration due to pixel conversion gaps that occur when converting to a scanning method for all television types.

(Prior art and problems) Conventionally, a television-type cathode ray tube is used in a bright display device that allows radar images to be observed in a bright place.
Scanning is converted into television-type horizontal and vertical scanning (TV scanning).

That is, from polar coordinates (Rθ coordinates) where the position is expressed by the direction (θ) and distance (6), to rectangular coordinates (XY coordinates) where the position is expressed by the distance on the horizontal axis (3) and the distance on the vertical axis (7).
format has been converted.

By the way, since the radar image plane is composed of a large number of pixels according to their coordinates, the image quality deteriorates due to missing writing pixels (conversion gaps) during the conversion process from the polar coordinate system of PPI display to the orthogonal coordinate system of TV scanning. There was a drawback that this occurred.

Generally, when converting polar coordinate display to rectangular coordinate display, the second
As shown in the figure, it is necessary to convert pixel values in polar coordinates, indicated by black circles, to pixel values in orthogonal coordinates, indicated by white circles.

In this case, due to the relationship between the number of scanning lines in the polar coordinate system and the pixel size in the orthogonal coordinate system, in a portion relatively close to the origin, as shown in Figure 3, multiple Rθ The values of the coordinates correspond, and in a place relatively far from the origin, a pixel at the Rθ coordinate cannot correspond to one pixel at the K A situation arises.

Pixel dropouts occur particularly frequently in areas far from the origin, especially in the direction where the angle to the vertical axis is +8n (n = 011.2.3), and on a CRT screen, holes appear in the radar image (target or clutter). It appears like this. In Cartesian coordinates, since the pixel shape is square, this may be visually emphasized, which degrades the image quality.

A method of improving the resolution in the θ direction may be considered to compensate for the above disadvantages, but this is difficult because it requires faster processing due to the time taken to write video data.

(Means for Solving All Problems) The present invention aims to eliminate the above-mentioned drawbacks, solve the deterioration in display quality of the radar image plane due to missing pixels, and provide a t-radar scan conversion method.

The present invention provides R1 in the conversion from a polar coordinate system to a rectangular coordinate system.
Since the transformed void coordinates are uniquely determined from the decomposed values of θ and the decomposed values of The same video data is also written to the transformed void coordinates.

That is, the present invention has the following configuration.

The analog radar video signal obtained by PPI scanning is converted into a digital video signal, and based on the distance signal from the azimuth/distance address generation section, the lateral signal is stored in a buffer memory having a storage element array corresponding to each distance unit, and the azimuth A rectangular coordinate address generator is provided which converts a position on polar coordinates indicated by the orientation and distance to an address display on rectangular coordinates based on the azimuth signal and distance signal from the distance address generator. In a radar scan conversion method in which digital signals on the buffer memory are stored in a video memory having orthogonal coordinate addresses based on a generated orthogonal coordinate address signal, the orthogonal coordinate address of a conversion gap that occurs when converting from polar coordinates to orthogonal coordinates is determined. A memory circuit that stores information,
A pixel extractor for determining whether or not the orthogonal coordinate address signal outputted by the orthogonal coordinate address generator is in the vicinity of the conversion gap address is provided with a memory; If it is determined that it is an address, the next step is to send a signal to the orthogonal coordinate address generator to instruct it to output the orthogonal coordinate address signal of the conversion gap, and to continue This is a radar scan conversion method that specifies the same read address.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing an example of the configuration of each means for carrying out the method of the present invention.

The analog radar video signal 10 from the radar receiver is A
The output digital video signal 11 is converted into a digital video signal by the /p conversion section 100 and is temporarily stored in the buffer memory 101. Further, a radar trigger signal 13, a north signal 14 and an angle signal 15 from the radar receiver are inputted to an azimuth/distance address generator (hereinafter referred to as an Rθ address generator) 102K.

The Rθ address generator 102 sends the distance count pulse 16 to the buffer memory 101 and receives the digital video signal 11.
Used for the uptake of An azimuth signal 17 and a distance signal 17' are also generated simultaneously and sent to a rectangular coordinate address generation section (hereinafter referred to as an XY address generation section) 103.

In the case of writing video data, the XY address generation section 103 generates an XY coordinate address signal 19 based on the azimuth signal 17 and sends it to the video memory 104 and pixel memory 105. This is Shibara Hua Memory 101
The digital video signal 12 from the video memory 104
will be written to. When enlightenment is finished, buffer memo I
J 101 prepares the next data based on the count signal 186 from the XY address generator 103. When a pixel is missing, the memory 105 compares the XY coordinate address signal 19 from the XY address generating section 103 to see if the coordinates currently being written are in the vicinity of the pixel missing. If the coordinates currently being written are coordinates near the pixel ticket, the pixel skip sends the neighborhood signal 20 to the XY address generator 103, and the XY address generator 103 generates the pixel address and sends it to the video memory. By stopping the count signal 18 at 104, the same digital video signal 12 as at the neighboring coordinates is written.

In the case of reading video data, the XY address generation unit 103 generates an XY coordinate address signal 1 for reading television.
9 is also generated and sent to the video memory 104. D/A converter 1
06 undergoes analog conversion from the video read data 21, sends the TV video data 22 to the display device 107, and displays the radar video on the display device.

(Effects of the Invention) As explained above, in the present invention, the shoulder address that causes pixel omission is stored, and at the point when the coordinates at which the digital video signal from the buffer memory is written to the video memory are the address of the pixel omission. If the pixel is in the vicinity, the same digital video signal is also written to the address when the pixel is omitted, so there is no pixel omission and there is an effect of providing a radar display without image quality deterioration.

[Brief explanation of drawings]

Claims (1)

[Claims] Converting an analog radar video signal by PPI scanning into a digital video signal, storing the digital video signal in a buffer memory having a storage element column corresponding to each distance unit based on a distance signal from an azimuth and distance address generation section, and A rectangular coordinate address generating section is provided which converts a position on polar coordinates indicated by the direction and distance to an address display on rectangular coordinates based on the direction signal and distance signal from the azimuth and distance address generating section, and the orthogonal coordinate address generating section In a radar scan conversion method in which digital signals on the buffer memory are stored in a video memory having a rectangular coordinate address based on a rectangular coordinate address signal generated by a rectangular coordinate address signal generated by a memory circuit that stores the
a pixel omission memory for determining whether or not the orthogonal coordinate address signal outputted by the orthogonal coordinate address generation section is in the vicinity of the conversion gap address; If it is determined that there is an orthogonal coordinate address signal, the next step is to send out a signal instructing the orthogonal coordinate address generation unit to output the orthogonal coordinate address signal of the conversion gap, and subsequently send the same signal to the buffer memory. A radar scan conversion method characterized by instructing a read address.