JPH11109013A - Target-detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a traveling target by discriminating the traveling target by a threshold processing and measuring a target position, converting a picture element position to latitude/longitude coordinates, and displaying them. SOLUTION: Satellite image data 14 for retaining a first image data memory 7 are inputted to a binarization means 8, binarization data 15 are processed by a threshold from a threshold-setting means 9 for discriminating a background sea surface from a ship, and ship picture element data 16 being calculated by a position-calculating means 10 are outputted. Image pick-up conditions of an earth curvature or the like are considered based on the latitude/longitude values at four corners of a satellite image being calculated in advance, each picture element of the satellite image is coded by the map coordinate value, a topology coordinates conversion means 24 converts the picture element position of the detected ship to a topology coordinates value, and ship topology coordinates data 27 are outputted. A latitude/longitude value generation means 25 inputs a topology coordinates value and generates latitude/longitude display data 28, and a display device 13 mixes the data with image display data 18 and automatically displays the result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting a moving target using an image including the moving target acquired by a flying object such as a satellite. Here, for convenience of explanation, an apparatus for detecting a ship using an image acquired by a satellite will be described below.

[0002]

2. Description of the Related Art The monitoring of the navigational status of ships at sea is an important monitoring task of national agencies for controlling illegal fishing and illegal immigration, and for monitoring the activities of naval ships in countries of interest. Attempts are being made in various countries to monitor vast maritime ships using satellite images that have the following characteristics. In this case, it is not only possible to quickly detect the ship in flight, but also to be able to quickly identify its geographical latitude / longitude position and what kind of ship it is from satellite images in advance, which will enable the subsequent launch of aircraft, etc. This is extremely important in planning an operation.

[0003] Fig. 11 is a diagram for explaining the arrangement relationship of ship imaging by satellites, where 1 is a satellite, 2 is the earth's surface, 3 is a satellite orbit, 4 is a line instantaneous field of view, 5 is an imaging field of view, and 6 is a maritime ship. It is. The satellite 1 usually orbits a polar orbit passing near the north and south poles to observe almost the entire surface of the earth. FIG. 11 shows a situation where the earth surface 2 is imaged from the orbit 3. . In recent years, the image sensor mounted on the satellite 1 uses a line sensor having a pixel array in a direction perpendicular to the traveling direction, and a linear instantaneous visual field 4 represents a ground surface imaging portion of the line sensor at a certain time. . By scanning the linear instantaneous visual field 4 for a certain time while the satellite 1 flies on the orbit 3, an imaging visual field 5 having a certain extent is imaged, and a ship 6 on the sea is imaged.

FIG. 12 shows a part of a configuration of this kind of apparatus generally used for inputting a satellite image and extracting a ship from the sea surface as a background. Reference numeral 7 denotes first image data. Memory, 8 binarization means, 9 threshold setting means, 10 position calculation means, 11 marker generation means, 12
Denotes superimposing means, 13 denotes a display device, 14 denotes satellite image data, 15 denotes binarized data, 16 denotes ship pixel position data, 17 denotes marker display data, 18 denotes image display data,
19 is mixed display data. In FIG. 12, the satellite image data 14 of the observation sea area is first stored in the first image data memory 7.
The output is input to the binarizing means 8, and a portion having a luminance higher than the threshold value set by the threshold value setting means 9 is logically 1, and the other portion is binarized as logical 0. . The logical 1 part corresponds to the target ship, and the binarized data 15
Is output to the position calculating means 10. Position calculation means 1
At 0, the position of the center of gravity of the binary image is calculated, and the pixel position is input to the marker generating means 11 as ship pixel position data 16. The marker generating means 11 generates marker display data 17 surrounding the center of gravity position, and
The mixed display data 19 is output to the display device 13 by mixing with the image display data 18 in 2.

FIG. 13 is a view showing an example of a display in a conventional ship detecting device, wherein 20 is a display device screen, 21 is a detected ship, 22 is a marker, and 23 is a wake. The wake generated by a moving ship is clearly observed in the optical image, and it can be clearly observed over a longer distance in the synthetic aperture radar image than in the optical image. It is possible to distinguish a fake from a sailing ship. In this figure, a ship with a sea surface as a background is displayed as a high-brightness detection ship 21, and a marker 22 is displayed surrounding the detected center of gravity.

[0006]

In order to detect a ship by satellite, it is important that the geographical position of the detected ship be quickly and accurately determined because of the subsequent dispatch of an aircraft or the like. The main function is to detect and display ships on the screen. In an example in which the monitoring of the coastal area is mainly performed, the coastal terrain is usually included in the imaging field of view at the same time, and the detected ship position is measured based on the known coastal terrain. However, if the surrounding area is all sea and there are no known points in the field of view, interpolation is performed individually based on only the latitude and longitude values of the four corners of the image calculated in advance from the orbital position of the satellite and the angle of view axis. It is necessary to calculate the position of the detected ship, which takes time for processing, which makes it difficult to operate quickly and has poor positioning accuracy of the position. Furthermore, in order to determine the type of the detected ship, it is necessary to compare the shape of the image with the shape of the existing ship one by one to make a judgment. It was time-consuming, and it was extremely difficult to classify a large number of ships sailing on the sea within the required time, which hindered rapid operation.

[0007]

According to a first aspect of the present invention, there is provided a ship detecting apparatus for detecting a ship by discriminating a sea surface as a background from a ship by threshold processing from a first image data memory holding a ship image. Means, means for measuring the pixel position of the detected ship, and individual pixels of the satellite image are coded by these geographical coordinate values in consideration of imaging conditions such as earth curvature based on the latitude and longitude values of the four corners of the satellite image. Means for converting the detected ship pixel position into geographical coordinate values and outputting these ships, the detected position,
It is provided with means for displaying latitude and longitude coordinate values.

A ship detecting apparatus according to a second aspect of the present invention includes a means for detecting a ship, a means for measuring a pixel position on a screen of a detected ship, a means for storing ship image data, and a method for converting a pixel value of a ship image into a ship. Means for adding in the direction perpendicular to the course direction and converting the brightness distribution in the course direction; means for storing the course direction brightness distribution data of the known ship; course direction brightness distribution data of the detected ship and course direction brightness of the known ship It comprises means for measuring the similarity with the distribution data, and means for displaying the similarity.

A ship detecting apparatus according to a third aspect of the present invention includes a means for detecting a ship, a means for measuring a pixel position on a screen of a detected ship, a means for storing ship image data, and a method for detecting pixel values of a ship image. Means for adding in the direction orthogonal to the course direction and converting it into a brightness distribution in the course direction, means for measuring the position of the peak of the course direction brightness distribution of the detected ship, and storing the position of the peak of the course direction brightness distribution of the known ship Means for measuring the similarity between the position of the peak of the luminance distribution in the course direction of the detected ship and the position of the peak of the luminance distribution in the course direction of the known ship, and means for displaying the similarity It is.

A ship detecting apparatus according to a fourth aspect of the present invention includes a means for detecting a ship, a means for measuring a pixel position on a screen of the detected ship, a means for storing ship image data, and a calculation of a center of gravity of the ship image. Means for calculating the moment amount of the ship pixel intensity distribution around the position of the center of gravity, means for storing the moment amount of the known ship, and measuring the similarity between the moment amount of the detected ship and the moment amount of the known ship. And means for displaying the similarity.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 shows a part of the configuration of a first embodiment of a ship detecting apparatus according to the present invention, wherein 24 is a geographic coordinate conversion means, 25 is a latitude and longitude value generation means, 26 is geographic coordinate reference data, and 27 is a ship geography. Coordinate data 28 is latitude / longitude display data. FIG. 2A is a diagram showing an example of a display according to the first embodiment, and 29 is a latitude / longitude display.

In general, a satellite image has 10 scenes per scene.
The latitude / longitude values of the four corners of the image of km km are calculated in advance from the position on the satellite orbit, the attitude angle, and the optical axis angle of the sensor at the time of imaging, so that the geographical coordinates of a known point in the captured image need not be checked one by one. However, generally, the accuracy of the above 4 is within 1 km.
The geographic coordinates of the corner can be obtained. In general, the satellite image data has a square arrangement, and in rare cases, a rectangular arrangement in terms of pixel arrangement. FIG. 2B is a diagram for explaining the arrangement of pixels in the image, where 30 is an arbitrary pixel and 31 is west →
The azimuth indicating the east direction, and 32 is the azimuth indicating the north → south direction. For simplicity, the number of pixels is assumed to be a square matrix of N × N pixels, and the upper left (northwest) corner is coordinate (0,0) and the upper right (northeast) corner is coordinate (0, N) as shown in FIG. , The lower left (southwest) corner is represented by coordinates (N, 0), and the lower right (southeast) corner is represented by coordinates (N, N). When the coordinates of an arbitrary pixel 30 are (m, n), the longitude value X and the latitude value Y at the pixel coordinates are generally expressed by Equation 1 by higher-order affine transformation using the longitude and latitude values of the four corners. be able to. The ship pixel position data 16 calculated by the same method as that of the conventional apparatus is input to the geographic coordinate conversion means 24, where the coordinate conversion coefficients A11, A12,
A13, A21, A22, and A23 are input as geographic coordinate reference data 26, and (X, Y) shown in Equation 1 are calculated by the geographic coordinate conversion means 24, and the ship's geographic coordinate data 27 is calculated.
Is output. The ship geographic coordinate data 27 is input to the latitude / longitude value generating means 25, and latitude / longitude display data 28, which is character and numerical data necessary for displaying the latitude / longitude display 29 shown in the display example of FIG. 2, the display shown in FIG. 2 is automatically displayed on the display device 13 by being mixed with the image display data 18 and the like, similarly to the conventional device.

[0013]

(Equation 1)

Embodiment 2 FIG. FIG. 3 is a diagram showing an example of the configuration of the second embodiment of the ship detecting apparatus according to the present invention.
Is a second image data memory; 34 is a gate generating means;
5 is width direction addition compression means, 36 is correlation operation means, 37 is existing ship reference data memory, 38 is ship image data, 3
Reference numeral 9 denotes ship compressed image data, and reference numeral 40 denotes correlation operation result data. FIG. 4 is a diagram showing a distribution of image signals according to the second embodiment, and FIG. 5 is a diagram showing a distribution of the image signals after addition and compression. Is the short axis direction of the ship, 44 is the luminance axis, and 45 is the ship compressed image data distribution.

In FIG. 3, the image display data 18 is input to a second image data memory 33 and temporarily stored therein, and the ship pixel position data 16 detected by the same method as in the conventional apparatus is input to the gate generating means 34. Is done. The gate generation means 34 generates a gate signal for validating an image in a size range several times the normal size of the ship centering on the detected ship position, and this is input to the second data memory 33, and the sea surface is scanned. Ship image including ship image data 38
It is cut out as. A ship image data distribution 41 in FIG. 4 shows an example of the distribution of the ship image data 38. In this example, two peaks are arranged in the direction of the major axis direction 42 of the ship. The ship image data 38 is input to the width direction addition / compression means 35 for the purpose of shortening the calculation time and reducing the influence of the fluctuation of the luminance distribution due to the change in the ship azimuth. As a result, as shown in the ship compressed image data distribution 45 in FIG.
It is converted into ship compressed image data 39 having a dimensional distribution.
The ship compressed image data 39 is input to the correlation calculating means 36. The existing ship reference data memory 37 holds a large number of compressed image data created by the above-described axial addition compression based on the ship image data distribution of a known ship created by a simulator or the like from a known ship shape. The correlation calculating means 36 calculates the similarity with the compressed ship image data 39, outputs the result as correlation calculation result data 40, and displays it on the display device 13 together with the conventional ship image. FIG.
Is a diagram showing an example of this display. The identification number of the detected ship, its latitude and longitude coordinate values, and the course and
Along with the speed, the names of ships arranged in descending order of similarity and their correlation coefficients (the higher the similarity, the higher the similarity).
As a result, the type of ship and the name of the ship can be automatically discriminated, and the accuracy is indicated as a correlation coefficient, so that the reliability of ship identification can be known as a measure of judgment.

Embodiment 3 FIG. 7 is a view showing an example of the configuration of the third embodiment of the ship detecting device according to the present invention.
Is a peak point position measuring means, and 47 is peak point position coordinate data. FIG. 8A is a diagram for explaining the signal processing according to the third embodiment, where 48 is the first peak point position, and 49 is the second peak point position.
Is the peak point position. The compressed ship image data 39 obtained by the same method as in the second embodiment is input to the peak point position measuring means 46. As shown in FIG. 8 (a), the ship compressed image data distribution 45 generally has a different brightness peak distribution for each type of ship. For example, a synthetic aperture radar image is shown in FIG. 8 (b) for a tanker. The bridge portion located at the stern has a unique brightness distribution 48a, and a combat ship such as an escort ship has a unique brightness distribution 48b due to onboard components as shown in FIG. 8 (c). Therefore, it is possible to identify the type of ship by measuring the position of the peak of this unique luminance distribution and comparing it with those of known ships. FIG.
In the example of (a), the peak point position coordinate data 47 corresponding to the coordinate values of the first peak point position 48 and the second peak point position 49 of the ship longitudinal axis direction 42 are obtained by the peak point position measuring means 4.
6, the similarity with the brightness peak position coordinate data of the known ship stored in the known ship reference data memory 37 is measured by the correlation calculating means 36. The calculation of the similarity with the peak position coordinate data requires a smaller amount of calculation than the calculation of the similarity of the image, so that the calculation time can be reduced. The obtained correlation calculation result data 40 is input to the display device 13 in the same manner as in the second embodiment, and the identification data of the detected ship is automatically displayed as shown in FIG. The ship type or the ship name can be identified with high accuracy.

Embodiment 4 FIG. 9 is a view showing a fourth embodiment of the ship detecting apparatus according to the present invention, and FIG. 10 is a view for explaining signal processing in the fourth embodiment. 50 is a center-of-gravity point calculating means, 51 is a moment amount calculating means, 52 is moment amount data and 53 is the position of the center of gravity. In FIG. 9, the ship image data 38 cut out in the same manner as in the second embodiment is input to the center-of-gravity point calculating means 50. In general, the brightness distribution of ships differs from ship to ship, and the difference is grasped as a rotation-invariant amount that does not depend on the ship azimuth by calculating the moment amount of pixel brightness centering on the center of gravity of the ship image. be able to. By grasping this rotation-invariant amount, even when the sea waves are intense and it is difficult to observe the wake and it is difficult to identify the course and direction of the ship, ship characteristics can be obtained regardless of the ship direction, The degree of similarity with a ship can be obtained. The center-of-gravity point calculating means 50 calculates the position coordinates (Xc, Yc) of the center of gravity of the binary image of the ship and the like, and inputs the coordinates to the moment amount calculating means 51 to be used as the center coordinates for calculating the moment amount. In the moment amount calculating means 51, the calculation shown in Expression 2 is performed.
The moment amount Mn is calculated. This moment amount is
In general, if the ship dimensions are the same, the ship brightness distribution becomes larger as the ship becomes more asymmetrical from inside the ship. For example, in a synthetic aperture radar image of a tanker, as shown in FIG. Since a strong luminance is generated, it has a large moment value. On the other hand, a battleship has a strong luminance distribution near the center as shown in FIG. Is smaller than that of the tanker, because the distance is small. As described above, the moment amount data 52 different for each type of ship is input to the correlation calculating means 36, and the similarity with the moment amount of the known ship held in the existing ship reference data memory 37 is calculated. 40, and the same ship identification as in the second embodiment is displayed on the display device 13.

[0018]

(Equation 2)

In the first to fourth embodiments, a device for detecting a ship using images acquired by satellites has been described. However, the present invention uses an image acquired by a flying object such as a satellite, an aircraft, or an airship. Needless to say, the present invention can also be applied to a device for detecting a moving target such as a ship, a passenger ship, a cargo ship, a vehicle (tank, trailer, bus, truck, etc.).

[0020]

According to the first aspect of the invention, since the moving target can be automatically detected and the position coordinates indicated by the latitude and longitude can be automatically obtained, it is possible to promptly shift to a subsequent action such as an aircraft dispatch. There is an effect that can be.

According to the second aspect, the type of the detected moving target or the name of the moving target can be known together with the accuracy thereof, which can contribute to a determination in determining a subsequent action such as an aircraft dispatch. effective.

According to the third aspect of the present invention, the type of the detected moving target or the name of the moving target can be known together with the accuracy thereof in a shorter time because of a small amount of calculation, and the subsequent action such as aircraft dispatch can be determined. This has the effect of contributing to speeding up the decision.

According to the fourth aspect, it is difficult to detect a wake, and the type of the detected moving target or the name of the moving target can be known together with its accuracy even in a situation where the direction of the moving target cannot be determined. This has the effect of contributing to speeding up the determination in determining subsequent actions such as aircraft dispatch.

[Brief description of the drawings]

FIG. 1 is a first embodiment of a ship detection device according to the present invention;
FIG.

FIG. 2 is a first embodiment of a ship detection device according to the present invention;
FIG. 3 is a diagram for explaining an example of display in FIG. 1 and an arrangement of pixels of an image.

FIG. 3 is a second embodiment of the ship detection device according to the present invention;
FIG.

FIG. 4 is a second embodiment of the ship detection device according to the present invention;
FIG. 5 is a diagram showing a distribution of image signals in FIG.

FIG. 5 is a second embodiment of the ship detection device according to the present invention;
FIG. 5 is a diagram showing a distribution of image signals after addition compression in FIG.

FIG. 6 is a second embodiment of the ship detection device according to the present invention;
It is a figure which shows a part of display in.

FIG. 7 is a third embodiment of the ship detection device according to the present invention;
FIG.

FIG. 8 is a third embodiment of the ship detection device according to the present invention.
FIG. 4 is a diagram for explaining signal processing of FIG.

FIG. 9 is a fourth embodiment of the ship detection device according to the present invention;
FIG.

FIG. 10 is a diagram illustrating signal processing in a fourth embodiment of the ship detection device according to the present invention.

FIG. 11 is a diagram illustrating the arrangement relationship of ship imaging by satellites.

FIG. 12 is a diagram showing a part of the configuration of a conventional ship detection device.

FIG. 13 is a diagram showing an example of a display in a conventional ship detection device.

[Explanation of symbols]

1 satellite, 2 earth's surface, 3 satellite orbits, 4 line instantaneous field of view, 5 imaging field of view, 6 naval vessels, 7 first image data memory, 8 binarization means, 9 threshold setting means,
10 position calculation means, 11 marker generation means, 12 superposition means, 13 display device, 14 satellite image data, 15 binarized data, 16 ship pixel position data,
17 marker display data, 18 image display data, 19
Mixed display data, 20 display screens, 21 detected ships, 22 markers, 23 tracks, 24 geographic coordinate conversion means, 25 latitude and longitude value generation means, 26 geographic coordinate reference data, 27 ship geographic coordinate data, 28 latitude and longitude display data, 29 Latitude and longitude display, 30 pixels, 31 west →
East direction, 32 North → South direction, 33 Second image data memory, 34 Gate generation means, 35 Width addition compression means, 36 Correlation operation means, 37 Existing ship reference data memory, 38 Ship image data, 39 ships Compressed image data, 40 Correlation calculation result data, 43 Ship short axis direction, 44 Luminance axis, 45 Ship compressed image data distribution, 4
6 peak point position measuring means, 47 peak point position coordinate data, 48 first peak point position, 48a luminance distribution specific to tanker, 48b luminance distribution specific to battleship, 49
Second peak point position, 50 centroid point calculation means, 51 moment amount calculation means, 52 moment amount data, 53
Position of the center of gravity.

Claims (4)

[Claims] 1. An apparatus for detecting a moving target using an image acquired by a flying object such as a satellite, the first device holding an image including the moving target acquired by a flying object.
Means for distinguishing the background and the moving target from the image data memory by threshold processing to detect the moving target, means for measuring the pixel position on the screen of the detected moving target, and A target detecting device comprising: means for converting into coordinates; and means for displaying these moving targets, detected positions, and latitude and longitude coordinate values. 2. An apparatus for detecting a moving target using an image acquired by a flying object such as a satellite, wherein the moving target is detected from image data including the moving target acquired by the flying object; Using the means for measuring the pixel position of the detected moving target on the screen and the image data, the pixel value of the moving target image is added in a direction orthogonal to the ship course direction and converted into a course direction brightness distribution. Means, storage means for storing the course direction luminance distribution data of the known moving target, and measuring the similarity between the detected course direction luminance distribution data of the moving target and the course direction luminance distribution data of the known moving target. And a means for displaying the degree of similarity. 3. An apparatus for detecting a moving target using an image acquired by a flying object such as a satellite, wherein the means for detecting the moving target from image data including the moving target acquired by the flying object; A means for measuring a pixel position of the detected moving target on the screen, and a means for adding the pixel value of the moving target image in a direction orthogonal to the course of the ship by using the image data and converting the pixel value into a luminance distribution in the course of the course. Means for measuring the position of the peak of the course direction luminance distribution of the detected moving target; storage means for storing the position of the peak of the course direction luminance distribution of the known moving target; and A target for measuring a similarity between the position of the peak of the course direction luminance distribution and the position of the peak of the course direction luminance distribution of the known moving target; and a means for displaying the similarity. Detector . 4. An apparatus for detecting a moving target using an image obtained by a flying object such as a satellite, means for detecting the moving target from image data including the moving target obtained by the flying object, Means for measuring a pixel position on the screen of the detected moving target, and means for calculating a center of gravity position of the moving target image using the image data,
Means for calculating the moment amount of the movement target pixel intensity distribution around the center of gravity, storage means for storing the moment amount of the known movement target, and the detected moment amount of the movement target and the moment of the known movement target A target detecting device comprising: means for measuring a similarity with an amount; and means for displaying the similarity.