JPH01248081A - Target detector - Google Patents

Abstract

PURPOSE:To detect a region, which shows the max. contrast when the brightness of a center-of- gravity position is a predetermined value or less and an area is a predetermined value or less, as a target, by calculating the area of each region, the magnitude of contrast thereof and the center of gravity thereof at every region from the output signal of an imaging part and calculating the brightness of the center-of-gravity position of the region at every region from the signal showing the center-of-gravity position and the signal from the imaging part. CONSTITUTION:The output signal from an imaging part 11 is inputted to a Laplacian filter 12 and the area, max. differentiated value and center-of-gravity position of each label surface on the basis of the data sent from both of the filter 12 and a labeling circuit 14 in a signal quantity calculation part 17. The positional data output of the label surface from the first operation part consisting of the filter 12-the calculation part 17 is inputted to a center-of- gravity position calculation part 18 being the second operation part and, the basis of the inputted data, the brightness of the center-of-gravity position of each label surface is calculated and the average brightness of the whole surface of the original image data from the imaging part 11 is calculated in an average brightness calculation part 19 and the position of a target is detected from said average brightness and the output of the calculation part 18 in a target detection part 20.

Description

[Detailed Description of the Invention] [Objective of the Invention 1 (Field of Industrial Application) The present invention is a target detection device used, for example, in an image-based flying object guidance device, which detects a target by image processing. This invention relates to a target detection device.

(Summary of the Invention) The present invention is a target detection device that detects a target by image processing, in which a flare including the sun or the like is not mistakenly recognized as a target during image processing, and movement of a target detection point is reduced.

(Conventional technology) A conventional target detection device is constructed as shown in FIG.

First, the imaging unit 11 images the vicinity of the target to obtain original image data. This original image data is subjected to two-dimensional two-dimensional differentiation by a Laplacian filter 12, then binarized by a binarization circuit 13, and labeled by a labeling circuit 14 for each continuous pixel portion. The label image data obtained by the labeling circuit 14 is sent to the signal amount calculation section 15 together with the differential value obtained by the Laplacian filter 12, where the area and maximum differential value (mountain last) of each label image data are calculated. Ru. The area and maximum differential value of each label image data obtained here are sent to the target detection section 16. Based on the data obtained by the signal amount calculation unit 15, the target height detection unit 16 selects a label that satisfies the following conditions ① and ② and has the maximum calculated value using, for example, equation (1). A target is identified using image data as a target, and a position that produces the maximum differential value of the label image data is output as a target position.

■ Area of each label image is less than a certain value ■ Target identification of large maximum differential value J = -Kl ・S + K2・D ・
...(1) (However, S2 area, D: maximum differential value, Kl,
2: constant for weighting) (Problem to be solved by the invention) However, in the conventional target detection device with the above configuration, when there are 7 flares (including the sun, etc.) on the screen, this flare and the target is very difficult to identify. For example, the third
As shown in figure (a), when inputting an image containing 7 rares B in addition to target A (in the figure, C is a mountain and D is a cloud), the 2-dimensional 2-dog differentiated image is shown in figure (b). The labeling is then performed as shown in FIG. 3(c). Here, for reference, the image processing calculation results for each label image are shown in Table 1.

From the results of this processing, condition (1) first makes it possible to distinguish large backgrounds such as mountains from targets, and condition (2) makes it possible to distinguish objects with weak contrast (low differential value) such as clouds. Therefore, the mountain #3 and the cloud #4 are excluded from the target due to conditions (2) and (2). Next, the 7 rares of #1 and the target of #2 are calculated using equation (1), and the targets are identified. However, in the case of the table above,
The calculation result (when K1=2=1) is I1...-IX10+lX25=15#2...-I
XI5+lX25=10. For this reason, flare #1
will be mistakenly identified as the target.

In addition, in the target detection device configured as described above, the point of the maximum differential output is set as the target position, but the position of the maximum differential value may change to a different position within the target depending on the attitude of the target, etc., so the target position output also fluctuates. . If such a device is mounted on a flying object, it will adversely affect guidance performance.

This invention solves the problem that conventional devices sometimes incorrectly identify the flare and the target when there is a 7-reare on the screen, and that the target position output fluctuates when the target's attitude changes. It is an object of the present invention to provide a target detection device which has a 7-7 identification function and in which the target detection point moves little near the center of the target.

[Structure of the Invention (Means for Solving the Problems) In order to achieve the above object, a target detection device according to the present invention includes an imaging section that outputs an image signal and an image signal that is supplied from the imaging section. a first calculation unit that derives the area, contrast size, and center of gravity for each region;
a second calculation unit that is supplied with a signal representing the center of gravity position from the calculation unit and a signal from the imaging unit and calculates the brightness of the center of gravity for each region; this second calculation unit and the first calculation unit; and a detection section for detecting an area where the luminance at the center of gravity is less than a predetermined value, the area is less than a predetermined value, and the contrast is maximum.

(Operation) The target detection device with the above configuration first determines the area, contrast size, and center of gravity for each region from the output signal of the imaging section, and then calculates the area, contrast size, and center of gravity for each region from the signal representing the center of gravity position and the signal from the imaging section. The brightness of the center of gravity is determined for each time. Next, an area in which the luminance at the center of gravity is less than or equal to a predetermined value, the area is less than or equal to a predetermined value, and the area has the maximum lump sum is detected as a target.

(Embodiment) An embodiment of the present invention will be described below with reference to FIG. However, in FIG. 1, the same parts as in FIG. 2 are designated by the same reference numerals, and only the different parts will be described here.

FIG. 1 shows the configuration when the present invention is applied to the target detection device shown in FIG. It has a target detection section 20 that identifies the target from the calculation results of the sections 17 to 19 and calculates the target position.

The signal amount calculation unit 17 calculates the area, maximum differential value, and center of gravity position (first-order moment amount) of each label image based on the data sent from the Laplacian filter 12 and the labeling circuit 14, and calculates the area, maximum differential value, and center of gravity position (first-order moment amount) of each label image. The signal amount calculation unit 17 constitutes a first calculation unit. The center of gravity brightness calculation unit 18 as a second calculation unit inputs the image data output from the imaging unit 11 and the center of gravity position data of each label image obtained by the signal amount calculation unit 17, and calculates the center of gravity position of each label image based on these. The brightness at the center of gravity is calculated.

The average brightness calculation unit 19 calculates the average brightness of the entire screen from the original image data (image signal) output from the imaging unit 11.

The operation of the above configuration will be explained below.

Generally, the flare is very bright and the target is darker than its surroundings. The present invention has focused on this, and the conditions that have been conventionally used as conditions for target identification in the target detection section 20.

The following conditions are given: ■ The area of each label image is less than a certain value. ■ In addition to the fact that the maximum differential value is large, ■ The luminance of the center of gravity of each label image is less than a certain value. In other words, the target detection unit 20 compares the brightness at the center of gravity of each label image obtained by the center of gravity brightness calculation unit 18 with the average brightness of the entire screen obtained by the average brightness meter 3 [19], A label image having a luminance twice as high (approximately 1.3 to 1.5 times) or more is likely to be flare, and is therefore determined to be not a target.

As a specific example, Table 2 shows the processing results of each calculation unit in the case of the image input shown in FIG.

Table 2 From this processing result, the mountain of #3 can be distinguished by the condition (1), the cloud of the well 4 by the condition (2), and the 7 rare of #1 by the condition (2). Therefore, target #2 can be correctly identified. The target detection unit 20 outputs the data of the center of gravity position of the target identified as described above as the target position.

Therefore, in addition to the conventional identification method, the target detection device having the above configuration is capable of distinguishing between a flare and a target, and since the detection point is the center of gravity of the target, stable data on the target position can be obtained.

[Advantageous Effects of the Invention 1] As described above, according to the present invention, it is possible to obtain a target detection device that is equipped with a flare identification function and in which the target detection point is located near the center of the target and does not move much.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the target detection device according to the present invention, FIG. 12 is a block diagram showing the configuration of a conventional target detection device, and FIG. 3 is an image of the target detection device to which the present invention is applied. It is an explanatory diagram showing an example of processing. 11... Imaging unit, 12... Laplacian filter,
13... Binarization circuit, 14... Labeling circuit, 1
5.17... Signal amount calculation unit, 16.20... Target detection unit, 18... Center of gravity brightness calculation unit, 19... Average brightness calculation unit.

Claims (1)

[Claims] (1) An imaging unit that outputs an image signal, a first calculation unit that calculates the area, contrast size, and center of gravity for each region of the image signal supplied from the imaging unit; a second calculation unit which is supplied with a signal representing the center of gravity from the center of gravity and an image signal from the imaging unit and calculates the brightness of the center of gravity for each region;
and a detecting section that is supplied with the output signal of the calculating section, and detects an area of maximum contrast in which the luminance at the center of gravity position is below a predetermined value and the area is below a predetermined value. Device.