JPH04553B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a radar image display method that performs interpolation processing when the number of sweep lines of a PPI display image in a weather radar device is thinned out.

(Prior Art) A weather radar device receives reflected waves from raindrops and the like, and obtains information such as the shape, moving speed, and intensity of rain areas. In currently operating weather radar equipment, the number of sweep lines on the PPI display that displays the radar image is approximately 3000 or more, and the included angle between adjacent sweep lines is approximately 0.12 degrees or less. be.

However, since the objects observed by weather radar are rain clouds that spread over a wide area, rather than hollow flying objects or ships on the sea, it is thought that it would be practical to display the PPI display by thinning out the sweep lines. . This means that when an angle signal and a video signal are received from a weather radar device, these data are processed by a microprocessor currently in practical use, and displayed on a display. This is convenient in cases where speed is limiting and it is not possible to display much data.

Therefore, in practice, it is conceivable to display the included angle between the sweep lines by about 1 degree, that is, about 360 sweep lines.

FIG. 3 is a block diagram showing the configuration of a conventional radar image display device that thins out and displays the sweep lines of PPI display. The video signal and angle signal from the weather radar device 1 are A/D converted by the signal processing device 2,
Video data and angle data of digital values are obtained, and the video data and angle data for each predetermined azimuth angle, for example, one sweep of one degree, are stored in the input buffer 3 by referring to the angle data. Next, the coordinate conversion circuit 4 refers to the sin/cos table from the angle data in the input buffer 3 to determine the orthogonal coordinate position where the video data sampled in the sweep direction should be displayed. to be displayed.

(Problem to be Solved by the Invention) However, the image displayed in this way widens at intervals toward the periphery of the screen of the display device, causing gaps in the displayed image and making the image difficult to see. There was a drawback. Therefore, it becomes necessary to interpolate and display the missing portions of the display image. The present invention focuses on the fact that the object to be displayed is something that spreads over a wide area, such as rain clouds, and uses a sufficiently practical interpolation method to interpolate and display the missing parts, making it look unnatural as an image of rain clouds, etc. The purpose is to obtain radar images that are not

(Means for Solving the Problems) The present invention provides the following features:
Video data and angle data for one PPI display sweep for each predetermined azimuth angle are stored in an input buffer, and from the angle data in the input buffer, the azimuth is within the 8-division circle of the PPI display screen. Then, from the sin/cos table in the memory, changes ΔX and ΔY in the orthogonal coordinates of the display position of the video data with respect to the angle data are calculated. Then XP=XP+ΔX and YP=YP+
Find the interpolation start coordinates by calculating ΔY, and then calculate the interpolation start coordinates XP, YP according to the result of the area determination above.
Interpolate multiple dots of the same data vertically or horizontally from Next, the next interpolation start coordinate on the same sweep line is found, and interpolation in the vertical or horizontal direction is performed in the same way. After repeating the above steps and displaying one sweep, store the video data and angle data for the next sweep in the input buffer, and sequentially repeat the steps above to display the missing parts of the radar image. This is an interpolated display.

(Example) Fig. 1 is a flowchart showing an embodiment of the present invention, and Fig. 2 is a block diagram showing an example of radar image display according to the present invention, in which 1 is a weather radar device for observing rain clouds, etc.; is a signal processing device that performs signal processing such as A/D conversion of the angle signal and video signal from the weather radar device 1; 3 is an input buffer that stores angle data and video data for one sweep; 4 is an orthogonal A coordinate conversion circuit that calculates changes in coordinates; 5 is a sin/cos table referred to by the coordinate conversion circuit 4;
6 is a CRT image display device that displays PPI radar images;
Reference numeral 7 denotes an interpolation processing circuit that executes procedures related to interpolation processing of the present invention.

(Operation) The video signal and angle signal from the weather radar device 1 are A/D converted by the signal processing device 2 to obtain digital video data and angle data. Under the control of the microprocessor, video data and angle data for one sweep for each predetermined azimuth angle are stored in the input buffer. The predetermined azimuth angle here is determined according to the signal processing speed of the microprocessor currently in use.For example, a PPI display radar image is displayed with 360 sweep lines around the entire circumference. Then, the azimuth angle is 1 degree.

FIG. 4 shows an example of angle data and video data stored in the input buffer. In this example, 2 bytes are allocated to angle data, and 254 bytes (N=254) are allocated to video data D1, D2, . . . , DN. Here, N = 254 means that the video data up to the maximum distance that can be displayed on the PPI display screen is sampled every 1/N unit distance, and the PPI
This is the number of display dots in the sweep direction displayed on the display screen.

In the coordinate conversion circuit 4, from the angle data for one sweep stored in the input buffer 3,
As shown in FIG. 6, it is determined to which region the sweep line to be displayed belongs among A-1, A-2, ..., D-2, which is divided into eight equal angles of the PPI display screen, As shown in FIG. 5, changes ΔX and ΔY in the orthogonal coordinates are calculated from the angle data and the unit distance in the sweep direction with reference to the sin/cos table 5.

Next, in the interpolation processing circuit 7, as shown in FIG. 1, the range counter RC is set to the number of dots N (=254) in the sweep direction, and the interpolation start coordinates XP and YP are set to zero. . Then, by calculating XP=XP+ΔX and YP=YP+ΔY, the interpolation start coordinates shown as D1 in FIG. 5 are determined. Here, from the obtained interpolation start coordinates XP, YP, the same display data is displayed in A-1, B-2,
In the C-1 and D-2 areas, the horizontal direction is shown in Figure 7A, and in the A-2, B-1, C-2, and D-1 areas, the vertical direction is shown in Figure 7B. Then, a plurality of dots, for example, five dots in the example of FIG. 7, are interpolated and displayed. Next, the next interpolation start coordinates, that is, the coordinates XP of the position indicated by D2 in FIG.
Find YP and interpolate multiple dots of the same data in the same way and display it. Thereafter, the calculation of the interpolation start coordinate and the interpolation display are repeated in the same manner, and the interpolation display is performed up to the last interpolation start coordinate DN of one sweep.

When the display of the radar image for one sweep is completed in the above manner, the angle data and video data for one sweep of the next azimuth are stored in the input buffer, and then the 8-division circular area described above is stored. Judgment Execute the following steps one by one.

As shown in FIG. 6, the sweep lines displayed in this manner become band-shaped sweep points with width, and the gaps between each sweep line disappear.

(Effects of the Invention) As explained above, according to the present invention, when displaying radar images of rain clouds etc. as a weather radar,
Even if the number of sweep lines in the PPI display has to be thinned out, there is no omission in the displayed image, and there is an advantage that an image that does not look unnatural as a weather radar image can be obtained.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention, FIG. 2 is a block diagram showing an example of a device according to the present invention, and FIG. 3 is a block diagram showing an example of a conventional device that thins out and displays sweep lines. Figure 4 shows data for one sweep stored in the input buffer, Figure 5 shows the positional relationship of interpolation start coordinates, Figure 6 shows the area of the 8-division circle on the display screen, and Figure 7 A and B are diagrams for explaining the sweep direction and the interpolation direction. 1... Weather radar device, 2... Signal processing device,
3...Input buffer, 4...Coordinate conversion circuit, 5...
...sin/cos table, 6...CRT image display,
7...Interpolation processing circuit, N...Sweep direction display dot number, RC...Range counter, D1, D2,...,
DN...Interpolation start position, XP, YP...Interpolation start coordinates, ΔX, ΔY...Cartesian coordinate change, A-1, A
-2,...,D-2...8 divided circular area.

Claims (1)

[Claims] 1. Of the video data and angle data output from the weather radar device and A/D converted by the signal processing device, the video data and angle data for one sweep of the PPI display are stored in the input buffer for each predetermined azimuth angle. , determine which area of the 8 equiangular circles on the PPI display screen it is located in from the angle data, and save the memory.
From the sin/cos table, the orthogonal coordinate change ΔX of the display position of the video data with respect to the angle data,
Calculate ΔY, interpolation start coordinates XP and YP
According to the calculation of =XP+ΔX and YP=YP+ΔY and the result of the area determination, the interpolation start coordinates XP, YP
A radar image characterized in that a missing part of a PPI display radar image is interpolated and displayed by repeatedly performing interpolation of multiple dots of the same data in the vertical or horizontal direction from the PPI display point as many times as the number of display dots in the sweep direction. Display method.