JPS63231283A - Laser scanning and converting device - Google Patents

Abstract

PURPOSE:To improve picture quality by interpolating gap picture elements with picture element data before and after a read picture element when the read picture element is a gap picture element containing no picture element data when picture element data are read out of a video memory. CONSTITUTION:Picture element data read out of the video memory 100 according to a television scanning system are transferred in order to registers 101-103. The output of the register 103 is sent out to a selector 106 and the outputs of the registers 101-103 are supplied to an interpolating ROM part 105. The interpolating ROM part 105 receives the respective outputs of the registers 101-103 and interpolates a gap picture element with the respective picture element data outputted by the registers 101 and 103 when only the output of the register 102 is the gap picture element containing no picture element data, thereby sending out the data to a selector 106 through a register 104. The picture element data selected by the selector 106 is supplied to a display device 108 through a D/A converter 107.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a radar scan conversion device, and particularly to a technique for improving image quality deterioration due to gap pixels, that is, missing pixels, which occur during scan conversion.

(Prior Art) As is well known, a radar scan conversion device uses PPI (Pla
In response to the fact that the (Po5ition Indication) instruction method is not suitable for use in bright places, this system attempts to scan-convert images acquired by a radar device and display them on a television monitor with high brightness.

That is, the image acquired by the radar device is based on the PPI scanning method, and is defined by polar coordinates (Rθ coordinates) expressed by direction (θ) and distance (R).

On the other hand, in TV-type horizontal and vertical scanning (TV scanning), the position of the target is determined by the distance on the horizontal axis (X) and the distance on the vertical axis (Y).
It is defined by orthogonal coordinates (XY coordinates) expressed as Therefore, the radar scan conversion device performs coordinate exchange on a radar video signal defined in polar coordinates according to the PPI scanning method to a rectangular coordinate format according to the television type scanning method, stores it in a video memory, and stores it in a video memory. Radar images are drawn on a television monitor using pixel data read from the radar.

(Problem to be Solved by the Invention) By the way, in the conversion process from the polar coordinate system of PPI scanning to the orthogonal coordinate system of TV scanning, when missing pixels (vacant pixels with no pixel data) occur when writing to the video memory. There is a problem in that this causes deterioration of image quality.

Generally, when converting polar coordinate display to rectangular coordinate display, the third
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, multiple pixels are detected for one pixel in the XY coordinates, as shown in Figure 4. R
The θ coordinate values correspond.

However, in a region relatively far from the origin, as shown in FIG. 5, there may be a gap pixel, that is, a missing pixel, which cannot correspond to one pixel in the XY coordinates and has no pixel data. It can be seen that the frequency of occurrence of this pixel dropout phenomenon increases as the distance from the origin increases. In the orthogonal coordinate system, the shape of a pixel is a rectangle, so if a pixel is missing, a display as shown in FIG. 6, for example, is displayed on the CRT screen.

In FIG. 6, the numbers indicate brightness levels and the ≠ marks indicate gap pixels.

That is, on the CRT screen, square holes appear here and there in the portion where the radar image (target or clutter) is drawn at brightness levels 3 to 8, degrading the image quality.

It is conceivable to improve the resolution in the azimuth (θ) direction to compensate for the above drawbacks, but this would require faster processing due to the relationship with the video data writing time, etc., and is difficult to implement.

The present invention was developed in view of the above-mentioned conventional problems, and its purpose is to provide radar scanning conversion that can improve image quality deterioration caused by missing pixels by interpolating empty pixels when selling video memory. The goal is to provide equipment.

(Means for Solving the Problems) In order to achieve the above object, the radar scan conversion device of the present invention has the following configuration.

That is, the radar scan conversion device of the present invention performs coordinate conversion of a radar video signal defined in polar coordinates according to the PPI scanning method into a rectangular coordinate format according to the television type scanning method, and stores the converted coordinate in a video memory. In a radar scan conversion device that draws radar images on a television type display device using pixel data read out from a video memory; pixel data read out from the video memory according to a television type scanning method is input in series and is sequentially transferred to a subsequent stage. A register having a three-stage configuration; When each output from the first, second, and third stages of the register is received, and only the output from the second stage is a gap pixel with no pixel data, the gap is interpolation processing means for interpolating pixels with each pixel data in the first stage and the third stage and outputting the pixel data related to the interpolation together with a selection signal; pixels sequentially output from the third stage of the register; data in the latter stage
a selector that transmits the pixel data to the /A converter, and selects and outputs the pixel data related to the interpolation that is output by the interpolation processing means when the selection signal is generated during the transmission; It is characterized by this.

(Function) Next, the function of the radar scan conversion device of the present invention configured as described above will be explained.

The register consists of three stages. Pixel data read out from the video memory according to the television-type scanning method is transferred to the first, second, and third stages of this register in order, and from the third stage, it is sent to the selector, and The outputs of the first stage, second stage, and third stage are provided to the interpolation processing means.

The interpolation processing means receives each output from the first, second, and third stages of the register, and when only the output from the second stage is a void pixel with no pixel data, the interpolation processing means converts the void pixel into a second stage. Interpolation is performed using each pixel data in the first and third stages, and the pixel data related to the interpolation is output to the selector together with a selection signal.

The selector transmits the pixel data sequentially output from the third stage of the register to the subsequent D/A converter, and when the selection signal is generated during the transmission, the interpolation processing means The pixel data related to the interpolation that is being output is selected and output.

As a result, on the display screen of a television-type display device, the gap pixel portion is not displayed as a hole as in the past, but is displayed with an appropriate brightness level, etc., and the image quality is improved. Ru.

As described above, according to the radar scan conversion device of the present invention, when reading pixel data from the video memory according to the television type scanning method, if the read pixel is a gap pixel with no pixel data, the pixels before and after it are Since the gap pixels are interpolated based on the pixel data, the gap pixels are not displayed as if there were holes as they were before, but are now displayed at an appropriate brightness level. , has the effect of improving image quality.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a radar scan conversion device according to an embodiment of the present invention. This radar scan conversion device includes a video memory 100
and registers 101 and 10, which are three-stage registers.
2. The video memory 100 basically includes the same 103, a register 104, an interpolation ROM unit 105 as an interpolation processing means, a selector 106, a D/A converter 107, and a television type display device 108. , a radar video signal defined in polar coordinates according to the PPI scanning method is converted into a rectangular coordinate format according to the television type scanning method and stored. Pixel data (digital signals of several bits) 10 are sequentially read out from this video memory 100 according to the TV scanning method, that is, for each pixel existing in the horizontal axis direction, and are applied to the first stage register 101.

Registers 101 to 103 operate according to a pixel clock 18 corresponding to one pixel on the horizontal axis.
The pixel data 10 given to the register 102 and the register 10
3 in sequence.

Then, the output of the register 103 at the final stage (third stage) is given to the selector 106, and the register 101
- 103 are supplied to an interpolation ROM section 105.

In the interpolation ROM section 105, the output 11 of the register 101, the output 12 of the register 102, and the output 13 of the register 103
First, it is determined whether the value of the output 12 of the register 102 is O.

Then, when the value of the output of register 102 is 0,
The pixel of the pixel data transferred to the register 102 is determined to be a gap pixel due to a pixel omission that occurred during coordinate transformation. Then, output 11 of register 101 and register 1
03 output 1B and ROM (read only memory)
The interpolated value data is output from the ROM as the 3 commercial addresses, and the interpolated value of the gap pixel is determined from both of the interpolated value data by linear interpolation, for example.

Focusing on the fact that the radar image information stored in the video memory 100 has a strong correlation in the horizontal axis direction, the horizontal axis pixel extraction is interpolated with the pixel data before and after it. Interpolated pixel data 14 obtained by
is sent to the register 104 along with the selection signal 15. The selection signal 15 is a signal indicating that interpolation processing has been performed. These interpolated pixel data 14 and selection signal 15 are stored in a register 10.
4, the positioning is controlled and input to the selector 106.

The selector 106 normally selects the third stage register 103.
output 13 to the subsequent D/A converter 107 as video signal 1
However, when the selection signal 15 is generated, the interpolated pixel data 1li is selected and output as the video signal 16 to the D/A converter 107.

The D/A converter 107 converts the video signal 16 into an analog video signal 17 and sends it to the display device 108.

As a result, a display as shown in FIG. 2, for example, is displayed on the CRT screen of the display device 108.

That is, in FIG. 6, for example, the part displayed as "8%6" is displayed as "8■6" as shown in FIG. Therefore, the pixel value is linearly interpolated and displayed as a pixel value of 7. In this way, even if a pixel is missing during coordinate transformation, it will not be displayed as is, so that poor image quality will be significantly reduced.

(Effects of the Invention) As detailed above, according to the radar scan conversion device of the present invention, when reading pixel data from a video memory according to the television type scanning method, the read pixels are empty pixels with no pixel data. In this case, the gap pixel is interpolated using the pixel data of the pixels before and after it, so the gap pixel is not displayed as a hole like in the past, but is displayed at an appropriate brightness level, etc. This has the effect of improving image quality.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the configuration of a radar scan conversion device according to an embodiment of the present invention, and FIG. 2 is a diagram showing a conventional display example shown in FIG. A diagram showing an example, FIG. 3 is a diagram showing conversion from polar coordinates to rectangular coordinates,
Figure 4 is a diagram of the relationship between a polar coordinate pixel and a rectangular coordinate pixel in the vicinity of the origin, Figure 5 is a diagram of the relationship between a rectangular coordinate pixel and a polar coordinate pixel in an area far from the origin, and Figure 6 is a table for when there is a missing pixel. It is a figure which shows an example. 100...Video memory, 101-104
...Register, 105...Interpolation R
OM section, 106...Selector, 107...
...D/A converter, 108...Display device.

Claims (1)

[Claims] A radar video signal defined in polar coordinates according to the PPI scanning method is converted into a rectangular coordinate format according to the TV-type scanning method and stored in a video memory, and the pixel data read from the video memory is used to generate a radar image. A radar scan conversion device for drawing images on a television type display device; a three-stage register in which pixel data read out from the video memory according to the television type scanning method is serially inputted and sequentially transferred to a subsequent stage; When each output in the first, second and third stages is received and only the output in the second stage is a gap pixel with no pixel data, the gap pixel is transferred to the first and third stages. an interpolation processing means for interpolating with each pixel data in and outputting the pixel data related to the interpolation together with a selection signal; transmitting the pixel data sequentially output from the third stage of the register to a subsequent D/A converter; a selector that selects and outputs the pixel data related to the interpolation that is output by the interpolation processing means when the selection signal is generated during the transmission thereof; Scan converter.