JPH0943348A - Radar image signal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the identification of the target of radar by computing the distribution of the picture elements in the cross section along plural cutting axes set optionally, as the quantity of features of a radar image, as regards the binary-coded radar image. SOLUTION: In respect of the picture element of the radar image produced with a radar image producing part 1, the distribution of the picture elements at the cross section along the cutting axis set optionally is obtained with a distribution detecting part 3, as to the radar image being binary-coded with a binary coding processing part 2. Next, out of the distribution at each cross section detected, a spread detecting part 4 computes the sum total of the picture elements after binary coding at every cross section, and obtains the spread of the radar image at each cross section. A quantity-of-feature computing part 5 computes the distribution of spread obtained at every cross section with the spread detecting part 4 on the axis orthogonal to the cutting axis, as the quantity of feature of the radar image. Hereby, the quantities of features can be compared among plural radar images.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar image signal processing apparatus for extracting a feature amount of a radar target in ISAR (Inverse Synthetic Aperture Radar) radar imaging.

[0002]

2. Description of the Related Art Recently, a radar image signal processing device for imaging a moving target by subjecting the radar echo to ISAR processing has been developed. In particular, it is created from the radar echo in order to identify the radar target. There is an increasing demand for comparing feature amounts among a plurality of radar images. However, conventionally, there is no specific method for calculating the feature amount that reflects the detailed structure of the target, so that the feature amounts cannot be compared, which hinders the identification of the radar target.

[0003]

As described above, since the conventional radar image signal processing device cannot calculate the feature amount that reflects the detailed structure of the target of the radar image, the radar image signal processing device does not calculate the feature amount among a plurality of radar images. The feature quantities cannot be compared, which hinders the identification of radar targets.

The present invention has been made to solve the above-mentioned problems, and it is possible to calculate the characteristic amount of a radar image, to compare the characteristic amount between a plurality of radar images, and to identify the radar target. It is an object of the present invention to provide a radar image signal processing device that can be used for the above.

[0005]

In order to achieve the above object, a radar image signal processing apparatus according to the present invention comprises a radar image creating section for creating a two-dimensional radar image from a radar echo, and a radar image creating section. The binarization processing unit that binarizes the pixels of the generated radar image, and the radar image binarized by the binarization processing unit, the pixel of the cross section along the cutting axis arbitrarily set The spread of the radar image at each cross section is calculated by calculating the sum of the binarized pixels for each cross section from the distribution detection section that obtains the distribution and the pixel distribution at each cross section detected by this distribution detection section. And a feature amount calculation unit that calculates a spread distribution obtained for each cross section by the spread detection unit on an axis orthogonal to the cutting axis as a feature amount of a radar image. It is made.

Alternatively, a radar image creating section for creating a two-dimensional radar image from the radar echo, a binarization processing section for binarizing the pixels of the radar image created by the radar image creating section, and the binary value With respect to the radar image binarized by the digitization processing unit, a distribution detection unit that obtains a distribution of pixels in a cross section along a cutting axis that is arbitrarily set, and a pixel of each cross section detected by the distribution detection unit A center point calculation unit that calculates the center point of the radar image for each cross section from the distribution, and this center point calculation unit obtains each cross section
A linear axis approximation of the distribution of the set of central points in a dimension, and a central axis calculation unit that calculates the direction of the approximated straight line as the central axis of the radar image, and the characteristics of the radar image from the central axis calculated by this central axis calculation unit And a feature amount calculation unit that calculates the amount.

In the radar image signal processing device having the above structure, a two-dimensional radar image is created from the radar echo, and the pixels of the radar image created by the radar image creating unit are binarized and then arbitrarily set. Obtain the distribution of pixels in the cross-section along the cutting axis, and calculate the sum of binarized pixels for each cross-section from the distribution of pixels in each cross-section to obtain the spread of the radar image in each cross-section. The spread distribution obtained for each cross section on the axis orthogonal to the cutting axis is calculated as the feature amount of the radar image.

Alternatively, the center point of the radar image is calculated for each cross section from the distribution of pixels in each cross section, and the distribution of the two-dimensional center point set obtained for each cross section is linearly approximated and an approximated straight line is obtained. Is calculated as the center axis of the radar image, and the feature amount of the radar image is calculated from the calculated center axis.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the configuration of a radar image signal processing device according to the present invention. FIG.
In FIG. 1, reference numeral 1 is a radar image creating unit that creates a two-dimensional radar image from the radar echo. Reference numeral 2 is a binarization processing unit that binarizes the pixels of the radar image created by the radar image creation unit 1. Reference numeral 3 denotes a distribution detection unit for obtaining the distribution of pixels in a cross section along a plurality of arbitrarily set cutting axes for the radar image binarized by the binarization processing unit 2.

Numeral 4 is a spread for obtaining the spread of the radar image in each cross section by calculating the sum of binarized pixels for each cross section from the distribution of pixels in each cross section detected by the distribution detection unit 3. It is a detection unit. Reference numeral 5 denotes a feature amount calculation unit that calculates the spread distribution obtained for each cross section by the spread detection unit 4 on the axis orthogonal to the cutting axis as the feature amount of the radar image.

In the above configuration, the processing contents will be described below with reference to FIGS. For example, after binarizing a radar image as shown in FIG.
For example, the X axis is selected, and the pixel value distribution is considered as shown in FIG. 3 for each Y axis value orthogonal to the X axis, and for example, the center is calculated as the center point 32.

Next, as shown in FIG. 4, the distribution of the center points with respect to the Y axis in the X axis direction is approximated by a straight line, and the inclination θ is used as the axis 34 of the radar image. Subsequently, the sum of the pixel values is calculated by using the axis 34 as a reference axis and the orthogonal axis 35 as a cross section, and the distribution of the sum of the pixel values is obtained as shown in FIG. Since this pixel value is of the image after binarization, it indicates the spread of the radar target in the direction of the axis 35. This Figure 5
Then, for example, the existence position of a plurality of peaks is set as a feature amount, and A,
The presence of three peaks B and C is characteristic of this radar image.

The detection of the center point 32 along the cutting axis 31 of the radar image detects, for example, the center of the spread of the radar target on the cutting axis 31, and the linear approximation detects the direction as the overall tendency of the point set. are doing. This is intended, for example, for detecting the ship's bow direction.

For example, A, B, and C shown in FIG. 5 detect the deviation of the spread of the silhouette on the radar image due to the structural difference of the radar target, which results in the structural difference of the radar target. It is possible to detect a difference in radar image due to.

The axis 34 of the radar image represents the long-axis direction of the radar target, and shows a reference direction such as the bow-stern direction when comparing a plurality of radar images.
Further, the feature quantities such as A, B, and C are considered to reflect the existence of structures unique to the radar target, and are useful for identifying the radar target.

Therefore, according to the above configuration, the feature amount of the radar image can be calculated, the feature amount can be compared among a plurality of radar images, and it can be useful for identifying the radar target.

In the above embodiment, the relative amount of a plurality of peaks is used for the calculation of the characteristic amount, but the present invention can be similarly performed by using the center of gravity of the spread, the maximum point, the one peak and the like. Further, the present invention is not limited to the above-described embodiment, and for example, as shown in FIG. 6, the center point calculation unit 6 determines from the distribution of pixels in each cross section detected by the distribution detection unit 3 to each cross section. The center point of the radar image is calculated for each cross section, and the central axis calculation unit 7 linearly approximates the distribution of the two-dimensional center point sets obtained for each cross section, and the direction of the approximated straight line is the center of the radar image. Then, the distribution of distances from the central axis (for example, the center of gravity) calculated by the central axis calculating unit 7 to each center point is calculated as the characteristic amount of the radar image by the characteristic amount calculating unit 8. Even
The same effect as the embodiment of FIG. 1 is obtained. Other than the above, the present invention can be implemented in various ways without departing from the scope of the invention.

[0018]

As described above, according to the present invention, the feature amount of the radar image can be calculated, the feature amount can be compared among a plurality of radar images, and it is useful for identifying the radar target. It is possible to provide a radar image signal processing device that can be used.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a radar image signal processing device according to the present invention.

FIG. 2 is a diagram showing a radar image created from a radar echo, a cutting axis for the radar image, a central axis and its angle, and a cutting axis used for calculating a feature amount in the embodiment.

FIG. 3 is a diagram showing an example of pixel values with respect to a cutting axis of a binarized radar image in FIG.

FIG. 4 is a diagram showing a manner in which an angle of the central axis is obtained by linearly approximating the central point calculated for each value of the Y axis in FIG.

FIG. 5 is a view showing the spread along the axis 35 in FIG.
FIG. 6 is a diagram showing that each peak of A, B, and C is detected as a feature amount.

FIG. 6 is a block diagram showing another embodiment according to the present invention.

[Explanation of symbols]

1 ... Radar image creation unit, 2 ... Binarization processing unit, 3 ... Distribution detection unit, 4 ... Spread detection unit, 5 ... Feature amount calculation unit, 6 ...
Central point calculation unit, 7 ... Central axis calculation unit, 8 ... Feature amount calculation unit.

Claims (7)

[Claims] 1. A radar image creating section for creating a two-dimensional radar image from radar echoes, a binarization processing section for binarizing pixels of the radar image created by the radar image creating section, and the binary value. With respect to the radar image binarized by the digitization processing unit, a distribution detection unit that obtains a pixel distribution in a cross section along a cutting axis that is arbitrarily set, and a distribution detection unit that detects the pixel distribution in each cross section detected by the distribution detection unit. A center point calculation unit that calculates the center point of the radar image for each cross section from the distribution, and a linear approximation of the distribution of the two-dimensional center point set obtained for each cross section by this center point calculation unit, and an approximated straight line A radar image signal including a central axis calculation unit that calculates the direction of the as the central axis of the radar image, and a characteristic amount calculation unit that calculates the characteristic amount of the radar image from the central axis calculated by the central axis calculation unit. Management apparatus. 2. The radar image signal processing device according to claim 1, wherein the center point calculation unit obtains a center of gravity on a cutting axis. 3. A radar image creating section for creating a two-dimensional radar image from radar echoes, a binarization processing section for binarizing pixels of the radar image created by the radar image creating section, and the binary value. With respect to the radar image binarized by the digitization processing unit, a distribution detection unit that obtains a distribution of pixels in a cross section along a cutting axis that is arbitrarily set, and a distribution detection unit that detects the distribution of pixels in each cross section A spread detection unit that obtains the spread of the radar image at each cross section by calculating the sum of binarized pixels for each cross section from the distribution, and the spread detection unit on the axis orthogonal to the cutting axis. A radar image signal processing device, comprising: a feature amount calculator that calculates a spread distribution obtained for each cross section as a feature amount of a radar image. 4. The radar image signal processing device according to claim 3, wherein the feature amount calculation unit calculates using the center of gravity of the spread. 5. The radar image signal processing device according to claim 3, wherein the feature amount calculation unit calculates using a maximum point of spread. 6. The radar image signal processing device according to claim 3, wherein the feature amount calculation unit calculates using a peak of spread. 7. The radar image signal processing apparatus according to claim 3, wherein the feature amount calculation unit calculates using the relative positions of a plurality of peaks of the spread.