JP2007051871A - Radar image display method and radar image display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent by simple constitution a pixel from being omitted, without raising up resolution, and to easily cope with even in the case where the pixel is omitted over consecutive two pixels or more, or the case where a resolution for radar information is brought down. <P>SOLUTION: In this radar image display of coordinate-transforming the radar information imparted in a polar coordinate form into orthogonal coordinates to be image-displayed, a drawing space is divided into optional quadrants, the sweep line existing quadrant and a sweep direction are judged in the drawing space, and a drawing point is added to the pixel adjacent to an original drawing element, in response to the sweep line existing quadrant and the sweep direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a radar image display method and a radar image display apparatus, and a method and apparatus for preventing pixel loss that occurs when radar information given in polar coordinate format is converted into orthogonal coordinates and displayed.

  Radar information is transmitted as a collection of straight lines and is given in polar coordinates (R, θ). Conventionally, when displaying radar information given in polar coordinates as an image, the radar information (R, θ) is transformed into orthogonal coordinates (x, y) and plotting data is plotted.

Specifically, in the case of radar information (R, θ), drawing is performed by plotting drawing data at coordinates determined by the following equation.
x = R · sinθ
y = R · cos θ
However,
x, y: Cartesian coordinates R: Distance from origin (0, 0) θ: Angle from Y axis

  Normally, it is ideal for the radar image to update the drawing data of all pixels by one rotation of the antenna.

However, since the sweep line extends in the azimuth direction in proportion to the distance R from the center, when the distance R from the center increases, the interval between the sweep line θ _n−1 and the drawing pixel of the sweep line θ _n is one pixel. As a result, pixels that are not plotted (not updated) are generated.

FIG. 12 shows a state where a pixel dropout occurs between the sweep line θ _n−1 and the sweep line θ _n . As the distance from the center increases, pixel omission occurs between sweep lines.

  Whether or not the display data of all the pixels can be updated without causing pixel omission by one rotation of the antenna depends on the angular resolution and distance resolution of the radar information. Originally, in order to prevent missing pixels, it is necessary to increase the angular resolution when the distance resolution is left as it is.

FIG. 13 is a diagram illustrating pixel omission that occurs when a radar image is drawn in a 1024 × 512 pixel pixel space with a distance resolution of 9 bits and an angular resolution of 12 bits. The dots in the figure indicate the pixels where pixel omission has occurred.

  Conventionally, in order to solve the pixel missing problem without increasing the angular resolution, for example, the following data complementing method has been proposed.

JP-A-11-352211

The method in sweep line theta _n, and compares the sweep line theta _n-1 immediately preceding, adjacent pixel of the sweep line theta _n-1 is, preceding and succeeding pixels in the lateral direction on the sweep line theta _n-1 Alternatively, it is detected whether the drawing pixel matches the sweep θ _n , and if it does not match, it is determined that there is a missing pixel, and the pixel missing is complemented with drawing data in the azimuth direction. is there.

  However, the above method requires a pixel missing detection unit for determining pixel missing, and the detection process is complicated. The complexity of the detection circuit means an increase in circuit scale, which often leads to problems such as an increase in processing time, an increase in the number of parts, a cost increase associated therewith, and an increase in power consumption.

  Also, with this method, pixel omissions that can be handled between each sweep line per antenna rotation is limited to one pixel per original drawing pixel, so that when two or more consecutive pixel omissions occur, There is a drawback in that it is not possible to easily cope with a decrease in resolution.

  The present invention eliminates the problems of the conventional apparatus as described above, prevents pixel loss by a simple configuration without increasing resolution, and lowers the resolution of radar information when pixel loss occurs for two or more consecutive pixels. It is an object of the present invention to realize a radar image display method and a radar image display device that can easily cope with cases.

  In order to achieve the above object, according to claim 1 of the present invention, in a radar image display device that displays an image by converting the radar information given in polar coordinate format into orthogonal coordinates, the drawing space is set to an arbitrary quadrant. In addition to dividing, it is possible to determine the quadrant and sweep direction in which the sweep line exists in this drawing space, and to add a drawing point to a pixel adjacent to the original drawing pixel according to the quadrant and sweep direction in which the sweep line exists. Features.

  According to a second aspect of the present invention, in the radar image display method according to the first aspect, the pixel to which the drawing point is added is a pixel adjacent to the original drawing pixel in the sweeping direction.

  According to a third aspect of the present invention, in the radar image display method according to the first or second aspect, the data displayed on the additional drawing pixel is the same as the original drawing pixel data.

  According to a fourth aspect of the present invention, in the radar image display method according to any one of the first to third aspects, the number of drawing pixels to be added is two or more.

  According to a fifth aspect of the present invention, in a radar image display device having a display unit and a coordinate conversion unit that converts the radar information given in polar coordinate format into orthogonal coordinates, the drawing space is divided into arbitrary quadrants and the sweep is performed in the drawing space. A quadrant determination unit that determines a quadrant in which a line exists, a sweep direction determination unit that determines a sweep direction, and a coordinate determination unit that determines the coordinates of a drawing point to be added according to the quadrant in which the sweep line exists and the sweep direction When the radar information given in polar coordinate format is converted to Cartesian coordinates for image display, the quadrant and sweep direction in which the sweep line exists in the drawing space are determined, and the quadrant and sweep direction in which the sweep line exists are determined. Accordingly, a drawing point is added to a pixel adjacent to the original drawing pixel.

According to a sixth aspect of the present invention, in the radar image display device according to the fifth aspect, the pixel to which the drawing point is added is a pixel adjacent to the original drawing pixel in the sweeping direction.

  According to a seventh aspect of the present invention, in the radar image display device according to the fifth or sixth aspect, the data displayed on the additional drawing pixel is the same as the original drawing pixel data.

  According to an eighth aspect of the present invention, in the radar image display device according to any of the fifth to seventh aspects, the number of drawing pixels to be added is two or more.

  In a ninth aspect of the present invention, in the radar image display device according to any one of the fifth to eighth aspects, each of the plurality of image memories can be accessed independently, and is sequentially associated with adjacent pixels. The image memory is written in accordance with outputs from the conversion unit and the coordinate determination unit.

  According to the quadrant where the sweep line exists and the sweep direction, the drawing point is uniformly added to the adjacent pixels of each sweep line, so that the pixel missing detection circuit can be omitted and the pixel missing can be prevented with a simple circuit configuration.

  With a simple circuit configuration, the processing time can be shortened, and there are advantages such as a reduction in the number of components, a cost reduction associated therewith, and a reduction in power consumption.

  In addition, by providing a plurality of image memories that can be accessed independently, the drawing data of the drawing pixels to be added can be simultaneously written to the image memory in addition to the original drawing pixels, and the writing speed can be reduced by one point. Can be equivalent to drawing.

  Also, depending on the relationship between the angular resolution and the distance resolution, there may be two or more consecutive pixel omissions between each sweep line. Even in such a case, the number of pixels to be added can be two or more. In addition, it is possible to easily prevent missing pixels without increasing the resolution of radar information, and it is possible to flexibly cope with changes in angular resolution and distance resolution associated with specification changes and design changes. Even when the resolution of the radar information is lowered and pixel omission between each sweep line becomes two or more consecutive pixels, it can be easily handled by adding two or more pixels in the same manner.

  Furthermore, since the drawing point is added to the pixel adjacent to the original drawing pixel of each sweep line in the sweep direction, the sweep direction can be applied in either the clockwise direction or the counterclockwise direction.

  In this way, by adding drawing points to adjacent pixels according to the quadrant where the sweep line exists and the sweep direction, pixel omission can be prevented with a simple configuration without increasing the resolution, and pixel omission can occur for two consecutive pixels. It is possible to realize a radar image display method and a radar image display device that can easily cope with the occurrence of the above or when the resolution of radar information is lowered.

  Hereinafter, a radar image display method and a radar image display device of the present invention will be described with reference to the drawings.

  FIG. 1 is a functional block diagram showing an embodiment of the present invention, in which a display unit 1, a coordinate conversion unit 2 that converts the radar information given in polar coordinates into orthogonal coordinates, and a quadrant determination that determines a quadrant in which a sweep line exists. Unit 3, sweep direction determining unit 4 for determining a sweep direction, quadrant in which a sweep line exists and a coordinate determining unit 5 for determining coordinates of a drawing point to be added according to the sweep direction, an image data processing unit for processing image data 6, an image memory 7 for storing drawing data to be displayed on the display unit 1, and a memory interface (memory I / F) 8 for controlling the image memory.

  The image memory 7 is composed of four memories A to D, and the memory I / F 8 is configured such that each memory can be accessed simultaneously and independently.

  2A to 2D are diagrams showing an example of a correspondence between each pixel on the display unit 1 and the memories A to D and a memory access method. Characters A to D assigned to each pixel mean memories (memory A to memory D) in which drawing data is stored, and the pixels and the memories are associated with each other in the arrangement shown in the figure.

  In the figure, a portion surrounded by a thick frame is a portion that is selected as a memory access range at the same time when the pixel “A” in the thick frame is an original drawing pixel. For example, when the drawing point is added to the upper side of the original drawing pixel, (b) is added to the lower side, (c) is added to the left side, d) As in the case of adding to the right side, the position of the drawing point to be added to the original drawing pixel is changed depending on which direction is adjacent.

  The direction in which the drawing point to be added is adjacent is determined from the quadrant where the sweep line exists and the sweep direction, and the address calculation is performed for each pixel of A, B, C, and D within the thick frame, and the original drawing point And the data of the drawing point to be added is simultaneously written in each corresponding memory.

  The reason why the memories A to D need to be independently accessible is that the memory corresponding to the original drawing pixel is not fixed to any one of the memories, and the memory A, This is because any of B, C, and D may occur.

  FIG. 3 shows an example of selection of a thick frame. In FIG. 3, (a) shows that the memory corresponding to the original drawing pixel is the memory A, (b) shows the memory B, and (c) shows In the case of the memory C, (d) shows the case of the memory D. When the memory for the original drawing pixel changes, the memory corresponding to the drawing point to be added also changes, so that it is necessary to be able to access each memory independently.

  FIG. 4 is a diagram illustrating a direction in which drawing points to be added are adjacent to the original drawing pixels and a corresponding memory. This figure shows a case where the sweep direction is clockwise and the radar image is displayed from 0 ° to 180 ° (π). The radar image area is classified into quadrant 0 to quadrant 5 according to the angle formed by the sweep line and the Y axis.

FIG. 4A shows the pixel position of the drawing point to be added when the sweep line is in quadrant 0. FIG. If A in the figure is the original drawing pixel of the sweep line, a drawing point is added to C at a position +1 in the Y-axis direction with respect to A, and the drawing data is written in the memory A and memory C.
FIG. 4B shows the pixel position of a drawing point to be added when the sweep line exists in the quadrant 1. If A in the figure is the original drawing pixel of the sweep line, a drawing point is added to D at a position +1 in the Y-axis direction and +1 in the X-axis direction with respect to A, and the drawing data is stored in memory A and memory D. Write to.
FIGS. 4C and 4D show pixel positions of drawing points to be added when the sweep line exists in quadrants 2 and 3. If A in the figure is the original drawing pixel of the sweep line, a drawing point is added to B at a position +1 in the X-axis direction with respect to A, and the drawing data is written in the memory A and memory B.
FIG. 4E shows the pixel position of a drawing point to be added when the sweep line exists in the quadrant 4. If C in the figure is the original drawing pixel of the sweep line, a drawing point is added to B at a position that is -1 in the Y-axis direction and +1 in the X-axis direction with respect to C, and the drawing data is stored in memory C and memory. Write to B.
FIG. 4 (f) shows the pixel position of the drawing point to be added when the sweep line is in the quadrant 5. If C in the figure is the original drawing pixel of the sweep line, a drawing point is added to A at a position -1 in the Y-axis direction with respect to C, and the drawing data is written in the memory C and memory A.

  FIG. 5 shows a case where the sweep direction is counterclockwise in the example shown in FIG.

FIG. 5A shows the pixel position of the drawing point added when the sweep line is in quadrant 0. FIG. If C in the figure is the original drawing pixel of the sweep line, a drawing point is added to A at a position that is -1 in the Y-axis direction with respect to C, and the drawing data is written in the memory C and memory A.
FIG. 5B shows the pixel position of the drawing point to be added when the sweep line exists in the quadrant 1. If D in the figure is an original drawing pixel of the sweep line, a drawing point is added to A at a position -1 in the Y-axis direction and -1 in the X-axis direction with respect to D, and the drawing data is stored in the memory D, Write to memory A.
FIGS. 5C and 5D show pixel positions of drawing points to be added when the sweep line exists in quadrants 2 and 3. If B in the figure is the original drawing pixel of the sweep line, a drawing point is added to A at a position -1 in the X-axis direction with respect to B, and the drawing data is written in the memory B and memory A.
FIG. 5E shows the position of the pixel of the drawing point added when the sweep line exists in the quadrant 4. If B in the figure is the original drawing pixel of the sweep line, a drawing point is added to C at a position +1 in the Y-axis direction and -1 in the X-axis direction with respect to B, and the drawing data is stored in memory B and memory. Write to C.
FIG. 5 (f) shows the pixel position of the drawing point to be added when the sweep line exists in the quadrant 5. Assuming that A in the figure is the original drawing pixel of the sweep line, a drawing point is added to C at a position +1 in the Y-axis direction with respect to A, and the drawing data is written in the memory A and memory C.

  In this way, the radar image area is divided into a plurality of quadrants, and the position of the drawing pixel to be added is determined according to the quadrant where the sweep direction and the sweep line exist.

  Since the drawing pixels are uniformly added to the original drawing pixels of the sweep line, the drawing is also once performed on the pixels that can be covered by the next sweep line. However, since it is immediately updated to the latest information by the next sweep line, the old information (information of the pixel added in the previous sweep line) remains in a straight line updated by the next sweep line. There is no problem.

  Furthermore, the number of image memories used in the present embodiment is four, which are memories A to D. However, the number of image memories can be adjusted by the number of drawing points to be added and the quadrant division method, and the number is limited to four. It is not a thing. If the image memory for the square of the total number of the original drawing pixels and the drawing pixels to be added is prepared, the number of pixels to be added can be two or more.

  6 to 11 show another embodiment of the present invention.

  FIG. 6 shows an example in which the sweep direction is clockwise and the radar image is drawn from 0 ° to 180 ° (π). The area of the radar image is divided into four quadrants from quadrant 0 to quadrant 3, and in which direction the pixel is added to the original drawing pixel is determined according to the quadrant where the sweep line exists.

  FIG. 7 shows a case where the sweep direction is counterclockwise in the example shown in FIG.

  FIG. 8 shows an example in which the sweep direction is clockwise and the radar image is drawn from 0 ° to 360 ° (2π). The area of the radar image is divided into eight quadrants from quadrant 0 to quadrant 7, and in which direction the pixel is added to the original drawing pixel is determined according to the quadrant where the sweep line exists.

  FIG. 9 shows a case where the sweep direction is counterclockwise in the example shown in FIG.

  FIG. 10 shows an example in which the sweep direction is clockwise and the radar image is drawn from 0 ° to 360 ° (2π). The area of the radar image is divided into 12 quadrants from quadrant 0 to quadrant 11, and in which direction the pixel is added to the original drawing pixel is determined by the quadrant where the sweep line exists.

  FIG. 11 shows a case where the sweep direction is counterclockwise in the example shown in FIG.

FIG. 1 is a functional block diagram showing an embodiment of the present invention. FIG. 2 is a diagram showing an example of correspondence between pixels and memories A to D and a memory access method. FIG. 3 is a diagram showing an example of a portion to be selected as a range for memory access simultaneously. FIG. 4 is a diagram showing an embodiment of the present invention (angle 0 ° to 180 °, 6 quadrants, sweep direction is clockwise). FIG. 5 is a diagram showing an embodiment of the present invention (angle 0 ° to 180 °, 6 quadrants, sweep direction is counterclockwise). FIG. 6 is a diagram showing an embodiment of the present invention (angle 0 ° to 180 °, four quadrants, sweep direction is clockwise). FIG. 7 is a diagram showing an embodiment of the present invention (angle 0 ° to 180 °, four quadrants, and the sweep direction is counterclockwise). FIG. 8 is a diagram showing an embodiment of the present invention (angle 0 ° to 360 °, 8 quadrants, sweep direction is clockwise). FIG. 9 is a diagram showing an embodiment of the present invention (angle 0 ° to 360 °, 8 quadrants, sweep direction is counterclockwise). FIG. 10 is a diagram showing an embodiment of the present invention (angle 0 ° to 360 °, 12 quadrants, sweep direction is clockwise). FIG. 11 is a diagram showing an embodiment of the present invention (angle 0 ° to 360 °, 12 quadrants, sweep direction is counterclockwise). FIG. 12 is a diagram illustrating a state where a pixel dropout occurs between the sweep line θ _n−1 and the sweep line θ _n . FIG. 13 is a diagram illustrating a state in which pixel omission of a radar image has occurred in a conventional apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display part 2 Coordinate conversion part 3 Quadrant judgment part 4 Sweep direction judgment part 5 Coordinate determination part 6 Image data processing part 7 Image memory 8 Memory I / F

Claims (9)

  In the radar image display method that displays the image by converting the radar information given in polar coordinate format into Cartesian coordinates, the drawing space is divided into arbitrary quadrants, and the quadrant where the sweep line exists and the sweep direction are determined in this drawing space A radar image display method comprising: adding a drawing point to a pixel adjacent to an original drawing pixel in accordance with a quadrant in which a sweep line exists and a sweep direction.   The radar image display method according to claim 1, wherein the pixel to which the drawing point is added is a pixel adjacent to the original drawing pixel in the sweep direction.   3. The radar image display method according to claim 1, wherein the data to be displayed on the additional drawing pixel is the same as the original drawing pixel data. 4.   4. The radar image display method according to claim 1, wherein the number of drawing pixels to be added is two or more.   In a radar image display device having a display unit and a coordinate conversion unit that converts the radar information given in polar coordinate format into Cartesian coordinates, the drawing space is divided into arbitrary quadrants, and the quadrant in which the sweep line exists in the drawing space A quadrant determination unit that determines a sweep direction, a sweep direction determination unit that determines a sweep direction, and a coordinate determination unit that determines the coordinates of a drawing point to be added according to the quadrant where the sweep line exists and the sweep direction When the radar information given in is converted into Cartesian coordinates and an image is displayed, the quadrant and sweep direction in which the sweep line exists in the drawing space are determined, and the original quadrant and sweep direction in which the sweep line exists are determined according to the original quadrant and sweep direction. A radar image display device, wherein a drawing point is added to a pixel adjacent to a drawing pixel.   6. The radar image display device according to claim 5, wherein the pixel to which the drawing point is added is a pixel adjacent to the original drawing pixel in the sweep direction.   7. The radar image display device according to claim 5, wherein the data displayed on the additional drawing pixel is the same as the original drawing pixel data.   8. The radar image display device according to claim 5, wherein the number of drawing pixels to be added is two or more. Each of them can be accessed independently, has a plurality of image memories that are sequentially associated with adjacent pixels, and writes the image memory according to the outputs of the coordinate conversion unit and the coordinate determination unit. The radar image display method according to claim 5.

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