JP2001014469A - Ground target detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely judge entering of an effective range by comparing a maximum effective range with a distance calculated by a distance calculating means to output an intra-effective range-judging signal to a nose when the distance becomes equal to or shorter than a maximum effective range. SOLUTION: A ground target detector is provided with an image pickup camera 1 for outputting an image signal 101 picked up by operating a target, a terrain memory 3 for storing the image of an operating area as a terrain image, and a camera controlling device 12 for controlling the visual field angle of the camera 1. A maximum effective range R0 at the time of shooting forged fragments toward the ground target of the nose mounted to the ground target detector is previously set. At the time of receiving a range R from a range calculating circuit 5, a comparator compares it with the range R0 to judge it to be outside of an effective range to output no signal at the time of R>R0 and to judge it to be within the effective range to output an intra-effective range judging signal 107 to the nose 8 at the time of R<=R0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terrestrial target detecting apparatus, and more particularly, to processing of a photographed image to determine a distance to a target in a firing direction of a warhead, and when the distance to the target falls within an effective range. The present invention relates to a ground target detection device that outputs an effective range determination signal to a warhead.

[0002]

2. Description of the Related Art In general, a warhead of this type is carried by an unmanned aerial vehicle or the like to a space above a target point, fired, suspended by a parachute, and searched for a target on the ground while falling. When the value falls below the value, forged fragments and the like are fired toward the target.

[0003]

The above-mentioned conventional warhead has a drawback that, even if it is out of the effective range, it immediately detonates and fires a forged debris or the like when a target is detected, resulting in low accuracy in hitting. I have.

There is also a drawback that image data from the target point must be obtained in advance.

It is an object of the present invention to provide a means for improving the above-mentioned circumstances. The photographed image is processed, the distance to the target in the firing direction of the warhead is obtained, and the distance to the target is the effective range distance. It is an object of the present invention to provide a ground target detection device that outputs an effective in-range determination signal to a warhead when the vehicle enters the inside.

[0006]

According to the present invention, there is provided an apparatus for detecting a terrestrial target, comprising: an image pickup means for outputting an image signal obtained by scanning a target; and a terrain storage means for storing an image of a scanning area as a terrain image. Camera view control means for controlling the view angle of the imaging means, switching means for switching between writing the image signal in the terrain storage means or reading the terrain image from the terrain storage means, and the switching means. Control means for transmitting a switcher switching signal and also transmitting a field-of-view switching signal to the camera field-of-view control means; a template which is a part of the image signal output by the imaging means and a part of the terrain image read from the terrain storage means A correlation detecting means for obtaining a correlation with an image, and when a correlation is obtained between the image signal of the two consecutive frames and the template image. Inter-frame movement amount calculating means for calculating an inter-frame movement amount between image signals of frames, distance calculating means for calculating a distance R to the ground from the inter-frame movement amount, and a maximum effective range holding a maximum effective range distance R0 The range setting means compares the maximum effective range distance R0 with the distance R calculated by the distance calculation means. When the distance R becomes equal to or less than the maximum effective range distance R0, the in-effective range determination signal is generated. And a comparing means for outputting to

Further, the imaging means uses an imaging camera for capturing visible or infrared light for obtaining a continuous image of the ground.

[0008] Further, the terrain storage means, when the ground target detecting device of the present invention is emitted from an unmanned airplane or the like,
The image pickup means stores the image signal obtained by first photographing the ground as the terrain image.

Further, the camera view control means sets the camera view angle of the image pickup means to Θ1 when the ground target detecting device of the present invention is emitted from an unmanned airplane or the like, and sets the visual line of sight of the image pickup means to the ground surface. When the angle of the vertical line is Δ and the altitude at the time of release of the ground target detection device is R1, the imaging means first takes an image of the ground and stores the terrain image in the terrain storage means. The camera viewing angle of the means is switched from {1} to {0 = {1 × R1 / (R0 × cos}) ”.

[0010] Further, the correlation detecting means may be configured to determine a correlation between the template image composed of I pixels horizontally and J pixels vertically and the image signal composed of K pixels horizontally and H pixels vertically. Is defined as P (i, j) (where i and j are 1 ≦ i ≦ I, 1 ≦
j ≦ J), and the luminance of each pixel of the image signal is D
(K, h) (k and h are respectively 1 ≦ k ≦ K and 1 ≦ h ≦
H), the sum of luminance difference values for each pixel between the two images is obtained as C (k, h), and C (k, h)
Is

(Equation 1) After calculating C (k, h) for all combinations of k and h, the coordinate position of the image signal coincides with the center position of the template image when C (k, h) has the minimum value. Is output as the coordinate position of the correlation point.

Further, the inter-frame movement amount calculating means includes:
The distance of the topographic image stored in the topographic storage unit on the ground is defined as Δr, and the coordinate position of the correlation point output from the correlation detection unit is defined as M−
It is located at a position of m (M-1) pixels in the horizontal direction from the center of the image signal at the time of the image signal of the first frame, and from the center of the image signal at the time of the image signal of the Mth frame from the imaging means. When it is located at the position of m (M) pixels in the horizontal direction, the inter-frame movement amount is set to (m (M-1) + m
(M)) × Δr.

Further, the distance calculating means sets the angular velocity of the turn of the ground target detecting apparatus of the present invention to ω, and calculates a distance between the image signal of the (M-1) th frame and the image signal of the Mth frame from the image pickup means. 1 frame period, which is the time of
30 seconds, and the inter-frame movement amount is (m (M-1) +
m (M)) × Δr, the distance R to the ground surface
R = 30 × (m (M−1) + m (M)) × Δr / ω
Is characterized by the following.

When the comparison means receives the distance R from the distance calculation means, the comparison means compares it with the maximum effective range distance R0, and if R> R0, judges that the effective range is out of the effective range and outputs no signal. If R ≦ R0, it is determined that the vehicle is within the effective range, and the effective range determination signal is output to the warhead.

[0014]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the ground target detecting apparatus according to the present invention.

The embodiment shown in FIG. 1 includes an imaging camera 1 that outputs an image signal 101 obtained by scanning a target and capturing an image.
A terrain memory 3 for storing an image of a scanning area as a terrain image; a camera field-of-view controller 12 for controlling the viewing angle of the imaging camera 1; an image signal written to the terrain memory 3; Switch 14 for switching whether or not to read out the data.
And a control circuit 13 for transmitting a visual field switching signal 106 to the camera visual field controller 12, an image signal 101 output from the imaging camera 1, and a template image which is a part of the terrain image 103 read from the terrain memory 3. And a correlator 2 for obtaining a correlation. Further, an inter-frame movement amount calculation circuit 4 for obtaining an inter-frame movement amount between the two-frame image signals when a correlation is obtained between the image signals of the two consecutive frames and the template image; A distance calculation circuit 5 for calculating the distance R from the quantity to the ground, a maximum effective range setting circuit 7 for holding the maximum effective range distance R0, and a maximum effective range distance R0 and the distance R calculated by the distance calculation circuit 5 In comparison, when the distance R becomes equal to or less than the maximum effective range distance R0, the in-effective range determination signal 10
And a comparator 6 for outputting a signal 7 to a warhead 8.

FIG. 2 is a perspective view showing the external configuration of the ground target detecting device shown in FIG.

In FIG. 2, this ground target detecting device 20
Has an imaging camera 1 that captures an image of the ground to obtain a continuous visible image or infrared image, and a warhead 8, and the direction of the line of sight of the imaging camera 1 matches the warhead firing direction.

Next, the operation of the embodiment of the present invention will be described with reference to FIGS. 1 and 2 using FIGS. 3, 4, 5, 6, and 7. FIG.

FIG. 3 is a diagram showing a state in which the imaging camera images a target area on the ground.

In FIG. 3, the ground target detecting device 20
It is carried on an unmanned aerial vehicle or the like having an altimeter, transported over a target point, and emitted at a predetermined altitude. At this time, altitude information is received from an unmanned airplane or the like. After the release, it is suspended by a parachute and falls while turning at a constant angular velocity ω about a vertical line to the ground surface. While falling, the line of sight of the imaging camera 1 always keeps an angle ψ with the vertical line to the ground surface, and the imaging camera 1 scans in a swirl shape toward a target 11 on the ground in a scanning trajectory 10 with a field of view 9 of the imaging camera. I do. The imaging camera 1 photographs the ground and acquires image signals of a plurality of frames in time series. This image signal is composed of a finite number of pixels.

Immediately after the ground target detection device 20 is released from an unmanned aerial vehicle or the like, an image signal that the imaging camera 1 first searches for on the ground and shoots the image is stored in the terrain memory 3 as a terrain image.

FIG. 4 is a diagram schematically showing a terrain image stored in the terrain memory.

In FIG. 4, the terrain image 103 is composed of a finite number of pixels in both the horizontal and vertical directions. In this example, the terrain image corresponding to a section having a vertical and horizontal distance of Δr on the ground forms one pixel. I have. In addition, the luminance of each pixel is recorded as a signal level at a value of 1, 0.5, 0.1, or the like, forming a terrain image 103.

Next, the operation of the correlator 2, the camera visual field controller 12, the control circuit 13, and the switch 14 will be described with reference to FIG.

FIG. 5 is a diagram for explaining the relationship between the camera viewing angle of the imaging camera and the resolution distance of the terrain image.

In FIG. 5A, the ground target detecting device 2
Assuming that the predetermined altitude at the time of emission of 0 is R1, the line of sight of the imaging camera 1 always keeps the angle と with the vertical line to the ground surface, and the distance of the line of sight to the ground surface is R1 / cosψ.

Next, in FIG. 5 (b), assuming that the camera viewing angle at the time of emission in FIG. 5 (a) is Θ1, the camera instantaneous angle of view ΔΘ1 becomes the camera viewing angle Θ1 / number of pixels N. Therefore,
The resolution distance Δr1 of the ground surface corresponding to each pixel constituting the terrain image is as follows: Δr1 = camera instantaneous view angle ΔΘ1 × R1 / cosψ = {1 × R1 / (N × cosψ).

Here, an image signal 101 captured by the imaging camera 1 and a terrain image 103 stored in the terrain memory 3
Is correlated by the correlator 2, and it can be determined that the correlation between the two images appears most strongly when Δr0 = Δr1 when the resolution distance at the maximum effective range R0 is Δr0.

That is, if the camera viewing angle for obtaining the resolution distance Δr0 is switched from Θ1 to Θ0, Δr0 =
Since Θ0 × R0 / N, when it is substituted into the condition of Δr0 = Δr1, Θ0 × R0 / N = Θ1 × R1 / (N × cos
ψ), and after all, the strongest correlation appears when {0 × R0 = {1 × R1 / cos} ”.

As described above, when the ground target detecting device 20 is emitted from an unmanned airplane or the like, an image is taken at a narrow viewing angle Θ1 and the ground target detecting device 20
Is closer to the target, the viewing angle is switched to the wide viewing angle Θ0.

Immediately after the ground target detecting device 20 is released from an unmanned airplane or the like, an image signal obtained by first photographing the ground by the imaging camera 1 is stored in the terrain memory 3 as a terrain image. Since the turning angular velocity ω is known in advance, the turning time corresponds to the turning angle, that is, the turning time. Therefore, the control circuit 13 controls the time of first photographing the ground, and when the terrain image is completely taken into the terrain memory 3, the control circuit 13 sets the camera viewing angle of the imaging camera 1 to the camera viewing angle Θ0 = Θ1. A view switching signal 106 is sent to the camera view controller 12 to switch the camera view angle so that xR1 / (R0 × cosψ). The camera viewing angle of Θ0 can be easily obtained because the values of Θ1, R1, R0 and ψ are all known.

On the other hand, the terrain image in the terrain memory 3 is
The switching unit 14 is switched by the switching unit switching signal 105 from the control circuit 13 so as to be read.

In this way, while the ground target detection device 20 is approaching the ground surface, the correlation at the time of the maximum effective range R0 can be remarkably detected.

Next, a correlation value detecting operation in the correlator 2 will be described with reference to FIG.

FIG. 6 is a diagram for explaining a correlation value detecting operation in the correlator.

First, the correlator 2 cuts out an image of a predetermined area from the terrain image 103 stored in the terrain memory 3 and sets it as a template image 110. FIG. 6A shows a state in which the terrain image 103 is cut out, and FIG. 6B shows a template image 110.
The template image 110 includes I pixels horizontally and J pixels vertically.

Next, the correlator 2 superimposes the template image 110 and the image signal 101 photographed by the imaging camera 1, and calculates the sum of the luminance difference values for each pixel between the two images as C (k, h). ). The number of pixels of the image signal 101 is K pixels horizontally and H pixels vertically, and k (C, k, h)
And h are respectively 1 ≦ k ≦ K and 1 ≦ h ≦ H.

The luminance of each pixel of the template image 110 is represented by P (i, j) (i and j are 1 ≦ i ≦ I and 1 ≦ j, respectively).
≤ J), and the luminance of each pixel of the image signal 101 from the imaging camera 1 is represented by D (k, h) (k and h are respectively 1 ≤ k
≦ K, 1 ≦ h ≦ H), C (k, h) is

(Equation 1) Can be obtained by

For all k and h combinations, C (k,
After obtaining h), when C (k, h) is minimum, it can be determined that the correlation between the template image 110 and the image signal 101 is strongest. Therefore, the template image 1 at this time
The coordinate position of the image signal 101 that coincides with the center position of 10 is set as the coordinate position C1 of the correlation point, and the correlator 2 outputs this C1 as the coordinate position of the correlation point. FIG. 6C shows the coordinate positions of the correlation points output by the correlator 2.

Next, the operation of calculating the amount of movement between frames in the inter-frame movement amount calculation circuit 4 will be described with reference to FIG.

FIG. 7 is a diagram for explaining the operation of calculating the amount of movement between frames in the circuit for calculating the amount of movement between frames.

Now, the correlation value between the image signal 101 of the (M-1) th frame from the image pickup camera 1 and the template image 110 is detected by the correlator 2, and the coordinate position C1 of the correlation point moves leftward from the center of the image signal 101. It is assumed that the pixel is located at the position of m (M-1) pixels. FIG. 7A shows the relationship between the image signal and the coordinate position C1 of the correlation point at this time. In the image signal 101 of the next M-th frame, if the coordinate position C1 of the correlation point is located at the position of m (M) pixels to the right from the center of the image signal 101 (FIG. 7B), the M-1 frame The displacement of the coordinate position of the correlation point between the eye and the M-th frame is m (M-1)
+ M (M) pixels.

Therefore, between the (M-1) th frame and the Mth frame, the imaging camera 1 moves on the ground surface by (m (M-1)
+ M (M)) × Δr. That is, the distance that the visual field range of the imaging camera 1 has moved on the ground surface by scanning for one frame is (m (M−1) +
m (M)) × Δr. The distance moved by the visual field range is referred to as an inter-frame movement amount S.

The inter-frame movement amount S is obtained by the inter-frame movement amount calculation circuit 4 using the coordinate position C1 of the correlation point output from the correlator 2. As shown in FIG. 3, the ground target detection device 20 slowly descends while turning from the sky at a substantially constant angular velocity ω. The time between the (M-1) th frame and the Mth frame, that is, one frame period is 1/30.
If it is set to seconds, the distance that the image signal 101 has moved in one frame cycle is ω / 30 in terms of angle.

Assuming that m (M-1) + m (M) = Q, the inter-frame movement amount S calculated by the inter-frame movement amount calculation circuit 4 is S = Q × Δr.

The distance calculation circuit 5 uses the inter-frame movement amount S = Q × Δr obtained by the inter-frame movement amount calculation circuit 4 to calculate the distance R to the ground surface as R = Q × Δr / (ω / 30) = 30 × Q × Δr / ω

The maximum effective range setting circuit 7 has a maximum effective range distance R0 at which the warhead mounted on the ground target detecting device of the present invention fires forged fragments and the like toward the ground target.
Is set in advance. When receiving the distance R from the distance calculation circuit 5, the comparator 6 compares the distance R with the maximum effective range R0, determines that the effective range is out of the effective range if R> R0, and does not output any signal. If so, it is determined that the vehicle is within the effective range, and an in-effective range determination signal 107 is output to the warhead 8.

The warhead 8 has a separate target detection circuit for detecting a target on the ground from the image captured by the imaging camera. When the target is detected after the in-effective range determination signal 107 is output, the warhead 8 is forged only for the first time. Etc. are fired.

[0050]

As described above, the ground target detecting apparatus of the present invention obtains a correlation between an image signal captured by an imaging camera and a terrain image stored at the beginning of a search for a target on the ground.
The position displacement between the image frames giving the strongest correlation is detected, the distance R to the target is obtained from the corresponding inter-frame movement amount, and the image is taken in accordance with the resolution distance of the terrain image stored in the terrain memory. Since the camera's viewing angle is controlled, the correlation can be detected remarkably, and it is possible to reliably determine whether the distance R is within or outside the maximum effective range R0, and to reliably determine that the distance R is within the effective range. It has the effect of being able to do it.

Further, since it is not necessary to previously capture a ground image from above the target point as in the related art,
It has the effect of being able to detect autonomously within the effective range autonomously and improving the accuracy of hits.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a ground target detection device of the present invention.

FIG. 2 is a perspective view showing an external configuration of the ground target detection device.

FIG. 3 is a diagram illustrating a state in which an imaging camera images a target range on the ground.

FIG. 4 is a diagram schematically illustrating a terrain image stored in a terrain memory;

FIG. 5 is a diagram illustrating a relationship between a camera viewing angle of an imaging camera and a decomposition distance of a terrain image.

FIG. 6 is a diagram illustrating a correlation value detection operation in a correlator.

FIG. 7 is a diagram illustrating an inter-frame movement amount calculation operation in the inter-frame movement amount calculation circuit.

[Explanation of symbols]

 C1 Coordinate position of correlation point S Inter-frame movement amount R distance R0 Maximum effective range 1 Imaging camera 2 Correlator 3 Terrain memory 4 Inter-frame movement amount calculation circuit 5 Distance calculation circuit 6 Comparator 7 Maximum effective range setting circuit 8 Warhead 9 Field of view of imaging camera 10 Scanning trajectory 11 Target 12 Camera field of view controller 13 Control circuit 20 Ground target detection device 101 Image signal 103 Terrain image 105 Switcher switching signal 106 Field of view switching signal 107 Effective range judgment signal 110 Template image

Claims (8)

[Claims] 1. An image pickup means for outputting an image signal obtained by scanning a target and photographing, a terrain storage means for storing an image of a scanning area as a terrain image, and a camera view control for controlling a view angle of the image pickup means. Means for switching whether to write the image signal to the terrain storage means or to read the terrain image from the terrain storage means, and to send a switcher switching signal to the switching means, and to control the camera visual field. Control means for sending a visual field switching signal to the means;
A correlation detection unit that performs a correlation between the image signal output by the imaging unit and a template image that is a part of the terrain image read from the terrain storage unit, and the image signal and the template image of two consecutive frames. An inter-frame movement amount calculating means for obtaining an inter-frame movement amount between two image signals when a correlation is obtained between the two frames, and a distance calculating means for calculating a distance R to the ground from the inter-frame movement amount. A maximum effective range setting means for holding a maximum effective range distance R0, and comparing the maximum effective range distance R0 with the distance R calculated by the distance calculation means,
And a comparing means for outputting an in-effective range determination signal to the warhead when the distance R becomes equal to or less than the maximum effective range distance R0. 2. The ground target detecting apparatus according to claim 1, wherein the imaging means uses an imaging camera that captures visible or infrared light to obtain a continuous image of the ground. 3. The terrain storage means, when the ground target detecting device according to claim 1 is emitted from an unmanned aerial vehicle or the like, uses the image signal obtained by first photographing the ground by the imaging means as the terrain image. The ground target detecting apparatus according to claim 1, wherein the information is stored. 4. The camera view control means sets the camera view angle of the image pickup means to Θ1 when the ground target detection device according to claim 1 is emitted from an unmanned airplane or the like, and sets a visual line of sight of the image pickup means. When the angle of a vertical line with the ground surface is ψ and the altitude at the time of release of the ground target detection device is R1, after the imaging means first captures the ground and stores the terrain image in the terrain storage means, , The viewing angle of the camera of the imaging means is changed from {1} to {0 = {1 × R1 / (R0 × cos)}.
The ground target detecting apparatus according to claim 1, wherein the switching is performed. 5. The correlation detection means according to claim 1, wherein said template image is composed of I pixels horizontally and J pixels vertically, and said image signal is composed of K pixels horizontally and H pixels vertically. And the brightness of each pixel of the template image as P
(I, j) (where i and j are 1 ≦ i ≦ I and 1 ≦ j ≦
J), and the luminance of each pixel of the image signal is D
(K, h) (k and h are respectively 1 ≦ k ≦ K and 1 ≦ h ≦
H), the sum of luminance difference values for each pixel between the two images is obtained as C (k, h), and C (k, h)
Is: After calculating C (k, h) for all combinations of k and h, the coordinate position of the image signal coincides with the center position of the template image when C (k, h) has the minimum value. Is output as a coordinate position of a correlation point. 6. The inter-frame movement amount calculation means sets a resolution distance on the ground of the terrain image stored in the terrain storage means to Δr, and a coordinate position of the correlation point output from the correlation detection means is: At the time of the image signal of the (M−1) th frame from the imaging unit, the image signal is located at a position of m (M−1) pixels in the horizontal direction from the center of the image signal. Sometimes at the position of m (M) pixels in the horizontal direction from the center of the image signal,
The amount of movement between frames is (m (M−1) + m (M)) ×
The ground target detecting device according to claim 1, wherein the ground target detecting device is obtained by Δr. 7. The distance calculating means, wherein ω is the angular velocity of the turn of the ground target detecting device according to claim 1, wherein the image signal of the (M-1) th frame from the image pickup means and the image of the Mth frame. One frame period, which is the time between signals, is 1
/ 30 seconds and the inter-frame movement amount is (m (M-1)
+ M (M)) × Δr, the distance R to the ground surface
R = 30 × (m (M−1) + m (M)) × Δr / ω
7. The method according to claim 1, wherein:
2. The ground target detecting device according to 1. 8. When the comparison means receives the distance R from the distance calculation means, the comparison means compares it with the maximum effective range distance R0, and if R> R0, judges that the effective range is out of range and outputs no signal. 8. The ground target detection apparatus according to claim 1, wherein if R ≦ R0, it is determined that the vehicle is within an effective range, and the in-effective range determination signal is output to the warhead. 9.