JPH07113669B2 - Infrared anti-aircraft monitoring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an infrared anti-aircraft monitoring device which captures infrared rays emitted by a flying object such as an aircraft by an infrared television image pickup means to know the distance and direction to the flying object. Regarding

(Prior Art) Conventionally, as means for searching for and tracking a flying object such as an aircraft, there is a radar device by means of using radio waves, and a television image pickup device by means of visible light or infrared rays. The radar device emits radio waves from the antenna, captures the radio waves that propagate to the projectile, is reflected by the projectile, and returns, and knows the time until capture and the direction at the time of capture to determine the position information of the projectile. Is getting

In the case of a television image pickup device, two television image pickup devices are installed at a fixed distance and the distance information is obtained by detecting the parallax angle based on the same measurement principle as that of the optical distance measuring device.

(Problems to be Solved by the Invention) However, normally, in anti-aircraft monitoring by a radar device, it is extremely difficult to capture a target flying at a low altitude as a target because of reflected radio waves (clutter) from the sea surface or the ground surface.

In addition, the method of using a pair of television image pickup devices installed at a fixed distance has a drawback that the visual field becomes very narrow when the distance detection accuracy is increased because the television image pickup capability is limited. A wide field of view is indispensable for anti-aircraft surveillance applications, and even if it is limited to a target that is close to the surveillance target in the low altitude, a 360 ° field of view in the azimuth direction is generally required. The viewing angle cannot be satisfied at all.

Further, a television device using visible light has a problem that it is difficult to distinguish a background from a target, and it is disabled at night or under foggy weather.

The object of the present invention is, in view of the above-mentioned problems of the prior art, necessary and sufficient by using an infrared television image pickup device which is less disturbed by the sea surface and the clutter of the ground surface even when searching, detecting, and tracking a flying object approaching at low altitude. It is an object of the present invention to provide an infrared anti-aircraft monitoring device which has a wide range-finding capability and a field of view over a necessary azimuth range.

(Means for Solving the Problems) The present invention has the following means configuration in order to achieve the above object.

That is, the infrared anti-aircraft monitoring device of the present invention superimposes and compares the paired television image pickup means with the optical axes set in parallel at a constant interval a and the output video signals of the paired television image pickup means to compare both. The deviation amount α of the target image on the screen,
In a television distance measuring system having means for calculating a distance D to a target by a calculating means for calculating the mathematical expression D = a × f / α from the focal length f of the television image pickup means light receiving lens; A first imaging means group in which the John imaging means is arranged in an arc shape with the imaging surface facing outward in the radial direction, and a second imaging means group having the same configuration as the first imaging means group are provided at a predetermined distance. A plane including the arc of the first image pickup unit group and a plane including the arc of the second image pickup unit group are spaced apart from each other, and are arranged in the same direction on the plane. A plurality of pairs of television image pickup means are configured as one pair of the television image pickup means by one image pickup means in the first group and one image pickup means in the second group having the same relative position. Infrared anti-aircraft monitoring device and the above infrared A plurality of sky monitoring devices have the same azimuth direction, and the lines connecting the two center points of the circles including the two arc-shaped arcs of the infrared television image pickup means are parallel to each other and include two arcs. Infrared anti-aircraft monitoring devices, characterized in that the planes are arranged at a predetermined angle interval in the depression / elevation direction, and for each of the above-mentioned devices, the first image pickup means group and the second image pickup means group are arranged along respective arcs. It is an infrared anti-aircraft monitoring device characterized by being interlocked and movable.

(Operation) The operation of the infrared anti-aircraft monitoring device of the present invention having the above configuration will be described below.

First, the principle of measuring the distance to the target by a pair of television image pickup means with two units whose optical axes are set in parallel at regular intervals will be described.

FIG. 5 shows the principle of measuring the distance to the target 2 using the pair of television image pickup devices 1 and 1 '.

In FIG. 5, D is the distance to the target 2, a is the distance between the pair of television imaging devices 1 and 1 ', and θ is the parallax angle (radian) observed by the pair of television devices 1 and 1'. ). There is an approximate relationship between the three parties as D >> a.

FIG. 6 shows that when a target 2 is observed at a parallax angle θ by a pair of television image pickup devices 1 and 1'installed with their optical axes parallel to each other, the television image pickup devices 1 and 1'receive light. The positional relationship of the optical image of the target 2 on a surface is shown. In FIG. 6, 3 and 3'denotes a pair of television image pickup devices 1 and 1 ', respectively, a light receiving lens of 1', f denotes a light receiving lens 3 and focal lengths of 3 ', and 4 and 4'denotes a pair of televisions respectively. The light receiving surfaces of the image pickup device and 5, 5'are the light image positions of the target 2 imaged on the light receiving faces 4 and 4'of the image pickup device.

When the light receiving surface 4'of the image pickup device is superposed on the light receiving surface 4 ', the position occupied by the light image position 5'on the light receiving surface 4 of the image pickup device is 5 ", and the interval between the light image positions 5 and 5" is α. When I did
The three relationships of θ, f, and α have the following relationship approximately.

α = f × θ (2) Therefore, if α can be measured, the distance D to the target 2 can be obtained by the following equation combining the equations (1) and (2).

Two-dimensional infrared rays on a pair of television image pickup devices 1 and 1 '
Assuming that a CCD camera is used and the minimum pixel interval (pitch) on the infrared CCD cameras 1 and 1'is the two-dimensional CCD light receiving surface 4 and 4 ', ε is theoretically α as shown in FIG. It is possible to discriminate the optical image positions 5 and 5 ″ of the target 2 on the light receiving surface 4 when = 2ε, but here it is possible to discriminate when α = 4ε with some redundancy. the maximum measurable distance of the target 2 D _max is given by the following equation.

On the other hand, the viewing angle Θ that can be observed by a pair of infrared CCD cameras is N, which is the number of pixels on the two-dimensional CCD light receiving surface of the infrared CCD camera.
(Vertical) × N (horizontal) = N ² Becomes This value is usually as small as a few degrees.

Therefore, it is not possible to carry out sufficient anti-aircraft monitoring of the field of view with only one pair of television image pickup means.

The present invention uses two groups of image pickup means as shown in FIG. 8 in which a plurality of infrared television image pickup means are arranged in an arc shape with the image pickup surface facing outward in the radial direction in the anti-aircraft monitoring device.
As shown in FIG. 1, the groups are arranged in the same direction with a predetermined distance therebetween, and one image pickup means in the first group and one image pickup means in the second group having the same relative position in each group. Since a plurality of pairs of television image pickup means are constituted by one pair of television image pickup means, each pair simultaneously observes a plurality of different directions at a constant angular pitch, and thus a wide field of view can be observed. .

By making the edges of the viewing angles of adjacent pairs of television image pickup means just in contact with each other or slightly overlapping each other, the entire viewing angle is a wide range of continuous angles according to the number of pairs of image pickup means provided. Can be In addition, when the arrangement interval on the arc of each pair is wide and there is a gap angle that cannot be observed between a certain pair of viewing angles and the viewing angle of the adjacent pair in a fixed state, it corresponds to this gap angle. Therefore, by providing means for moving the first image pickup means group and the second image pickup means group in conjunction with each other along the arc, a wide viewing angle can be obtained as a whole. Also,
By arranging a plurality of such devices in the same manner as the circular center point and the circumferential direction of the arc-shaped arrangement of the infrared television image pickup means, and arranging planes including the arcs at predetermined angular intervals. In addition to the field of view at the angle in the circumferential direction, the field of view at the angle in the direction perpendicular to the field of view can be obtained. For example, if the angle in the circumferential direction is the horizontal azimuth angle, the angle in the direction perpendicular to the horizontal azimuth angle is the elevation angle (elevation angle), and the visual field can be obtained in both the horizontal direction angle and elevation angle ranges.

Further, since the infrared image pickup means is used as the television image pickup means in the device of the present invention, the image pickup is limited to the target generating heat, so that the cracks from the sea surface or the ground surface as in the radar device. It does not occur, and it can be monitored at night or under conditions of fog.

(Example) Hereinafter, an example of an infrared anti-aircraft monitoring device of the present invention will be described with reference to the drawings.

In this embodiment, the infrared cameras 1 and 1'which are television image pickup devices are arranged 10 m apart from each other, and the infrared camera 1, the light receiving lens 3 of the same 1'and the focal length f of the same 3'are 100 m.
m, the infrared camera 1, the light receiving surface 4 of the same 1 ', and the minimum pixel interval ε on the same 4'is 25 μ.

As a result, the maximum measurable distance D _max of the target 2 is calculated as 10 km from the equation (4). Further, since the number of pixels N of the light receiving surface 4 and 4'is set to 256, the viewing angle Θ of the pair of infrared cameras is 0.064 radian = 3.67 degrees from the equation (5).

FIG. 8 is a diagram obtained by equally spaced the p number of the infrared camera 1 ₁ to 1 _p along an arc 7 with a radius R around the center point 6. The light receiving lens of each infrared camera faces the outside of the arc. Opening angle facing the infrared camera 1 ₁ and the 1 _p of both ends is Ω.

FIG. 1 shows a situation in which the center points 6 and 6'of two arcs of the same construction as in FIG. 8 are juxtaposed by a distance A.

In FIG. 1, a total of P pairs of infrared cameras located at positions corresponding to the two arcs 7 and 7 ', respectively ₁ : ₁ :
1 _'1 to 1 _{p: 1' p} infrared camera 1 of the pair, the 1 '
Corresponding to, each has a field of view of Θ in the azimuth (horizontal direction) direction and has a field of view of Ω degrees as a whole. However, when the position on the arc 7 or _7'of each pair of infrared cameras 1 _pn or _1'pn is on the diameter forming φ degrees with respect to the front direction when viewed from the center point 6 or 6 ', I have a relationship.

a = Acosφ (6) where A is the center point 6 of the circle containing the arc 7 in FIG.
And the center point 6'of the circle containing the arc 7 '.

In this embodiment, the field of view in the magic mass (horizontal azimuth) direction assigned to each pair of infrared cameras of P pairs is set to 3 degrees, and the field of view of 90 ° in the azimuth (horizontal azimuth) direction is set by the infrared camera group of P pairs. To cover (Ω = 90), 30 pairs of infrared cameras (P = 30) are installed. In this case, since the maximum field of view of each pair of infrared cameras is 3.67 degrees, about 20% of each shared field of view overlaps at both ends between adjacent camera pairs. The image output of is connected.

FIG. 2 shows arcs 7 and 7'shown in FIG. 1 in the general case where a 360 ° field of view in the azimuth (horizontal direction) direction is required.
The situation is shown in which four P-pair infrared cameras arranged above are arranged with their directions changed by 90 degrees.

FIG. 3 shows a vertical cross section of the vertical plane including the alternate long and short dash line in FIG. 1 as viewed from the right side. The number of infrared camera rows that should be arranged in the vertical (height) direction with the visual field Θ of the infrared camera (one unit) when the surveillance target is limited to close targets at low altitude and the visual field in the height (elevation angle) direction is set to Φ degrees. There is the following relationship with Q.

In this embodiment, when the visual field Φ in the height (elevation angle) direction is 9 degrees, the array number Q of the infrared cameras is 3. By arranging 3 layers in this way, 1500m or less, 2
At km, it is possible to capture a target 2 in close proximity at an altitude of 300 m or less. From the above, the number of infrared cameras required to carry out 360-degree anti-aircraft surveillance is 2P x Q x 4 = 720.

Next, the outline of the signal processing procedure in the infrared anti-aircraft monitoring device of the present invention described above will be listed.

1. In the infrared CCD camera array (array) of P × Q pairs arranged on the two circular arcs 7 and 7'constituting one pair of the infrared surveillance infrared camera group described above, a pair of infrared C
The output image signal of the CD camera is superimposed on the image memory plane.

2. Detects targets (pairs) forming a pair on the superimposed image memory plane, and automatically initiates initial lock-on when the paired targets are displaced by four pixels on the CCD light receiving surface. After that, the tracking is performed.

3. Measure the azimuth (horizontal direction) and height (elevation angle) from the target position on the screen, and the range (distance) from the twin target distance α, and display it on the indicator (CRT) screen just like normal radar. At the same time as displaying, computer processing is performed to quickly determine whether or not to issue an interception instruction.

As is clear from the above detailed description of the embodiments of the present invention with reference to the drawings, the infrared anti-aircraft monitoring device of the present invention detects an approaching target in a low altitude which is difficult to be captured by a normal radar in all directions. It has the ability to track and is less likely to be disturbed by reflected waves (clutter) on the sea surface or on the ground.

It is suitable for detecting the tail flame of jets and missiles that are supposed to be targets because of the infrared sensing method. In addition, it is possible to measure not only azimuth (horizontal direction) and height (elevation angle) but also range (distance) with necessary and sufficient accuracy due to the observation method by a pair of compound-eye infrared camera group.
Since three-dimensional position information of the target similar to normal radar information can be obtained almost instantaneously (real time), high-speed computer calculation is possible not only for the position of the target but also for the flight direction and speed. In the above embodiment, it is possible to detect the three-dimensional position information of the target located at a distance of 10 km, which is about 30 times as long as the target is approaching at the speed of sound.
It shows that it can be detected in seconds, and it is a sufficient value as the time required for analyzing the flight information of the target and determining and executing the countermeasure based on the analysis result.

From the above, it is apparent that the present invention provides an anti-aircraft monitoring device for both sea and land for a target in low altitude, which has been extremely difficult in the past, and sufficiently satisfies the object of the present invention.

In the above embodiment, P infrared cameras were arranged and fixed on the arc 7 shown in FIG. 8 with an opening angle of Ω, but the infrared cameras were not fixed and the center point of the arc was set as shown in FIG. 6
As an axis of the radar, a circular motion is performed mechanically in the horizontal plane as in an antenna of a radar, and a single infrared camera is used to swing and scan the range of ω degrees. Cover the field of view (Ω = n
It is clear that the same effect can be obtained even by making ω). In the above embodiment, as shown in FIG. 3, the visual field in the height (elevation angle) direction is relatively narrow (for example, Φ = 9).
(Degrees)), but if it is expected that a target in low altitude will rapidly rise after approaching, it may be necessary to expand the field of view in the height direction to a maximum of 90 degrees. Also in this case, the number of rows Q of infrared cameras to be arranged in the vertical (height) direction should be increased as necessary, or a straight line connecting the center point 6 of the arc 7 and the center point 6'of the arc 7'in FIG. Obviously, the goal can be achieved by applying a mechanical scan in the vertical direction as the axis.

Further, in the above-mentioned embodiment, as shown in FIG. 2, the structure of four sets of arcs 7 and 7'is assumed in order to cover all directions of 360 °, but when the approach direction can be limited to the target, for example, It goes without saying that the purpose can be achieved only by the configuration of one set of arcs 7 and 7'as shown in FIG.

(Effects of the Invention) As described above, the infrared anti-aircraft monitoring device of the present invention is
Two groups of image pickup means in which a plurality of infrared television image pickup means are arranged in an arc shape with the image pickup surface facing outward in the radial direction are used, and these two groups are arranged in the same direction with a predetermined distance therebetween. Since one image pickup means in the first group and one image pickup means in the second group, which have the same relative position within each other, constitute a pair of television image pickup means, a plurality of pairs of television image pickup means are configured. , Each pair simultaneously observes a plurality of different directions at a constant angular pitch, which is advantageous in that a wide field of view can be observed.

If the angle pitch is narrower than the pair of viewing angles, a wide viewing angle without fixing is obtained, and if the angle pitch is wider than the pair of viewing angles, an arc is formed by the gap angle. A wide viewing angle can be covered by oscillating and scanning the two imaging means groups along.

Further, a plurality of the above infrared ray anti-aircraft monitoring devices have the same circular center point and circumferential direction of the arc-shaped arrangement of the infrared television image pickup means, and each plane including the arcs has a predetermined angular interval. By arranging in such a manner, not only azimuth but also elevation can be observed.

Further, in the device of the present invention, since the infrared television image pickup means is used as the television image pickup means, the image pickup is limited to the target generating heat. There is an advantage that clutter does not occur and it is possible to monitor even at night or under the condition of fog.

[Brief description of drawings]

1 and 2 are diagrams showing the configuration of an embodiment of the present invention, and FIG.
FIG. 4 is an explanatory view of a viewing angle in the vertical direction, FIG. 4 is a view showing a configuration of an embodiment of the present invention, FIGS. 5 and 6 are explanatory views of a distance measuring principle, and FIG. 7 is a pixel array on a light receiving surface. FIG. 8 is a diagram in which a plurality of television image pickup means are arranged in an arc shape. 1, 1 '... television imaging _{device, 1 1 ~1 p, 1'} 1 ~1 '
_p ... Infrared camera, 2 ... Target, 3,3 '... Receiving lens, 4,4' ... Receiving surface, 5,5 ', 5 "... Optical image position, 6,6'
…… Center point, 7,7 ′ …… Arc.

Claims (3)

[Claims] 1. A pair of television image pickup means having optical axes arranged in parallel at a constant interval a and output video signals of the paired television image pickup means are superposed and compared with each other to obtain a target image in both screens. A television distance measuring system provided with a means for calculating the distance D to the target by a calculation means for calculating the mathematical expression D = a × f / α from the deviation amount α and the focal length f of the light receiving lens of the television image pickup means. In a first image pickup means group in which a plurality of infrared television image pickup means are arranged in an arc shape with an image pickup surface facing outward in a radial direction, and a second image pickup means group having the same configuration as the first image pickup means group. Are separated by a predetermined distance, and the plane including the arc of the first image pickup means group and the plane including the arc of the second image pickup means group are aligned with each other, and are arranged in the same direction on the plane. Within the first group having the same relative position within each group Infrared anti-aircraft monitoring apparatus characterized by constituting a plurality of pairs of television image pickup means and the television pickup means constituting the pair with a and one imaging unit of the imaging unit in one and the second group. 2. A plurality of infrared anti-aircraft monitoring devices according to claim 1 have the same azimuth direction and two center points of a circle including arcs of two arc-shaped arrangements of respective infrared television image pickup means. An infrared anti-aircraft monitoring device, wherein connecting lines are parallel to each other and planes including two arcs are arranged at a predetermined angle interval in the depression / elevation direction. 3. The infrared anti-aircraft system according to claim 1 or 2, wherein the first image pickup means group and the second image pickup means group are movable along the respective arcs. Monitoring equipment.