JPH0815408A - Display apparatus for navigation - Google Patents

Abstract

PURPOSE:To extract a moving target by simple processing. CONSTITUTION:An inter-image operating part 22 operates the exclusive-OR of the image data at the previous scan read out of an image memory 16 and the image data of the scanning at this time. The partial image indicating the moving target is extracted from the result and stored in an image memory 24. An image processing part 26 extracts the shape feature of the partial image indicating the target based on the image data in the image memory 24. A CPU part 14 identifies the kind of the target based on the detected shape feature and imparts the patterns, the characters and the like indicating the result into a display control part 18. The display control part 18 forms the image based on the patterns and the characters from the CPU part 14 in addition to the image data in the image memories 16 and 24 and displays the signals on a display device 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a navigation display device mounted on a ship or the like.

[0002]

2. Description of the Related Art FIG. 2 shows the structure of a navigation display device according to a conventional example. The device shown in this figure includes a scan converter 10 for converting an image signal obtained by a radar device from a polar coordinate format to a rectangular coordinate format.

The scan converter 10 inputs a radar image signal obtained from a radar device, obtains a gyro signal obtained from a gyro compass and indicates a traveling direction of a ship or the like to be mounted, and a CP set by a user by an operation unit 12.
Coordinate conversion is performed using the range signal supplied via the U unit 14. The radar image signal converted into the rectangular coordinate format by the coordinate conversion is stored in the image memory 16 as image data. The display control unit 18 uses the image memory 16 based on information such as the display range supplied from the CPU unit 14.
The above image data is converted into an image signal and supplied to a raster scan type display 20, for example, a CRT. In this way, the radar image can be suitably displayed on the screen of the display 20 based on the radar image signal output from the radar device.

[0004]

However, in such a structure, the user has to gaze on the screen of the display in order to know which target is moving. Therefore, the above configuration is not suitable for observing moving targets.

A device called MTI (Moving Target Indicator) is an example of a device capable of extracting a moving target. In MTI, the Doppler frequency included in the signal received by the antenna of the radar device, that is, the frequency shift amount due to the relative movement of the target is detected, and the moving target is extracted based on the detected frequency shift. It But,
If a moving target is to be extracted by such a method, it is necessary to extract the frequency shift component from the signal received by the antenna, which is a troublesome process.

The present invention has been made to solve the above problems, and by processing image data obtained by coordinate conversion of a radar image signal, the Doppler frequency deviation of the received signal is processed. It is an object of the present invention to enable a moving target to be extracted and displayed without extracting the transferred amount.

[0007]

In order to achieve such an object, the navigation display device according to the present invention compares the image data of the previous scan with the image data of the current scan and extracts different partial images. Means for extracting the feature from the shape of the extracted partial image, and means for displaying information on the extracted partial image.

Further, the present invention is characterized in that the above comparison is executed as an exclusive OR operation.

The present invention is further characterized in that a partial image composed of data having a predetermined value or data having a value belonging to a predetermined range among the extracted partial images is a target of feature extraction. .

The present invention is further characterized in that the feature is the area of the partial image.

The present invention is characterized in that the displayed information is a character or a symbol indicating the type of the target appearing as a partial image on the image data.

[0012]

In the present invention, first, the image data of the previous scan and the image data of the current scan are compared, and different partial images are extracted. The scan here means
A period of one revolution of the antenna of the radar device. Further, the feature is extracted from the shape of the extracted partial image, and information about the partial image is displayed. Therefore, when the target object is moving, this target object is extracted as a partial image of the image data of the current scan that is different from the image data of the previous scan. It is possible to extract a moving target by relatively simple information processing regarding image data without performing processing such as extraction of Doppler frequency shift from a signal.

Further, in the present invention, the comparison between the image data of the previous scan and the image data of the current scan is executed as an exclusive OR operation. By performing such a calculation, the above-mentioned comparison and extraction of partial images are realized by a relatively simple calculation.

In the present invention, the partial image for extracting the feature is a partial image formed from data having a predetermined value or data having a value belonging to a predetermined range in the extracted partial image. Therefore, of the extracted partial images, the partial image that cannot be clearly regarded as a moving target is excluded from the target of feature extraction, and the processing efficiency is improved.

In the present invention, the feature extracted from the shape of the partial image is the area of the partial image. Since the area of this partial image represents the size of the target appearing as a partial image on the image data, when displaying the information related to the extracted partial image, the type of the moving target, etc., is displayed as the information. Can be displayed.

In the present invention, the displayed information is a character or symbol indicating the type of the target appearing as a partial image on the image data. Therefore, the user can quickly and suitably recognize the type of the target by looking at the displayed characters or symbols.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. It should be noted that the same or corresponding components as those of the conventional example shown in FIG.

FIG. 1 shows the structure of a navigation display device according to an embodiment of the present invention. The device shown in this figure uses a radar image signal supplied from a radar device as a gyro signal supplied from a gyro compass and an operation unit 12.
The scan converter 10 converts the polar coordinate format to the rectangular coordinate format based on the range signal set by.

The scan converter 10 stores the radar image signal converted from the polar coordinate format to the rectangular coordinate format in the image memory 16 as image data. The scan converter 10 also supplies the image data to the inter-image calculation unit 22. The inter-image calculation unit 22 includes the scan converter 1
The image data supplied from 0 and the image data stored in the image memory 16 by the scan converter 10 at the time of the previous scan, that is, the image data of the previous scan are input, and the image data of the current scan and the image data of the previous scan are input. Perform an exclusive OR operation. Inter-image calculation unit 2
2 extracts a partial image that seems to indicate a moving target by this exclusive OR operation, and CP of the extracted partial images
Only a partial image composed of data of values belonging to the intensity range set by the U unit 14 is stored in the image memory 24 as a partial image showing the moving target.

The image data of the partial image stored in the image memory 24 is read by the image processing unit 26. The image processing unit 26 extracts information on the shape feature of the target from the read image data, and extracts this information from the CPU unit 1.
4 For example, the image processing unit 26 obtains the area of the partial image read from the image memory 24, and supplies this to the CPU unit 14 as information indicating the shape feature. CPU
The unit 14 identifies what kind of target the moving target extracted based on this shape feature is, for example, what kind of ship, and displays information such as a figure and characters indicating the result. It is supplied to the display control unit 18. The display control unit 18
In addition to the image data stored in the image memory 16 and the image data relating to the moving target stored in the image memory 24, an image to be displayed based on a figure, a character, etc. supplied from the CPU unit 14 is displayed. The image signal is generated and supplied to the display 20. Therefore, on the screen of the display device 20, therefore, in addition to the radar image represented by the radar image signal, information about the moving target is also displayed.

Therefore, according to the present embodiment, the moving target is extracted by a relatively simple process regarding the image data without performing a process such as extracting the Doppler frequency shift component from the signal received by the antenna. be able to.
Further, the information on the extracted moving target can be displayed in an easily understandable form such as a figure or a character. This enhances the usability of the navigation display device, so that a device that is significant even for unskilled users is realized. Further, as described above, since only the image data belonging to the predetermined intensity range is extracted by the inter-image calculation unit 22, it becomes possible to perform the process only on the partial image that should be truly regarded as the target, and the process can be performed. Be more efficient.

In the above description, only the application to a ship is shown, but the present invention can be applied to other applications. In the case of application to a ship as described above, when it is used as a monitoring device such as a port monitoring radar, it is convenient for grasping the trend of a ship moving in a port.

[0023]

As described above, according to the present invention,
By extracting the partial image related to the moving target etc. by comparing the image data of the previous scan and the image data of the current scan and extracting the feature of the shape, while displaying the information on the extracted partial image, The moving target can be automatically extracted only by relatively simple processing relating to image data without performing processing such as extracting the Doppler frequency shift component from the received signal. As a result, a navigation display device with higher usability can be realized.

Further, since the comparison between the image data of the previous scan and the image data of the current scan is executed as an exclusive OR operation, the process of extracting the partial image can be realized by a relatively simple process. It is possible to realize simplification of the device configuration.

Further, since the partial image composed of the data having the predetermined value or the data having the value belonging to the predetermined range among the extracted partial images is set as the target of the feature extraction, it is truly a target. Partial images that cannot be regarded as can be excluded from the target of feature extraction, and the processing efficiency can be improved.

Further, according to the present invention, since the area of the partial image is extracted as the information showing the feature of the shape of the partial image, it is possible to classify the type of the target appearing as the partial image on the image data. become. Further, according to the present invention, since the character or the symbol indicating the type of the target appearing as the partial image on the image data is displayed, the user can quickly and accurately grasp the type of the target. become.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a navigation display device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a navigation display device according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 scan converter 12 operation part 14 CPU part 16 and 24 image memory 18 display control part 20 indicator 22 inter-image calculation part 26 image processing part

Claims (5)

[Claims] 1. A means for comparing the image data of the previous scan and the image data of the current scan to extract a different partial image, a means for extracting the feature from the shape of the extracted partial image, and the extracted portion. A navigation display device comprising: means for displaying information about an image; 2. The navigation display device according to claim 1, wherein the comparison is executed as an exclusive OR operation. 3. The navigation display device according to claim 1, wherein a partial image composed of data having a predetermined value or data having a value belonging to a predetermined range among the extracted partial images is a target of feature extraction. A navigation display device characterized by the following. 4. The navigation display device according to claim 1, wherein the feature is an area of a partial image. 5. The navigation display device according to claim 1, wherein the displayed information is a character or a symbol indicating the type of the target that appears as a partial image on the image data. .