JP2012189584A - Target detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a target detector capable of preventing erroneous detection or nondetection of a target irrespective of a small calculation size.SOLUTION: A radar reception signal from an aerial antenna 1 is quantized by an A/D converter 2 to be converted into a digital video signal. Coherent integration is carried out at a coherent integration unit 3, and the digital video signal is thinned at a distance/orientation thinning unit 4. Then, signal intensity is attenuated by an attenuation unit 5 according to the attenuation level of an attenuation map. Then, a threshold calculation/binarization unit 6 creates a histogram in a fixed region indicated by the digital video signal by a P tile method, and carries out binarization by using a threshold value exceeded by an upper P%. Then, a blank unit 7 sets the signal intensity of a detection unnecessary region to "0", and a contraction/expansion unit 8 carries out contraction and expansion to remove an isolated clatter. Then, a clustering unit 9 regards the continuous region of "1" as one target, and outputs it as detection target data.

Description

  The present invention relates to a target detection device that detects a target by processing a received signal (hereinafter referred to as a “radar received signal”) obtained by a radar.

  Conventionally, signal processing called CFAR (Constant False Alarm Rate) (hereinafter referred to as “CFAR processing”) is mainly used to detect a target from a radar received signal. In the CFAR process, a threshold is adaptively calculated by assuming that the signal intensity in the peripheral region in the distance direction of the target and the target follows a certain probability distribution, and binarization processing is performed using the calculated threshold to Identification from clutter is performed (for example, see Non-Patent Document 1).

  Further, Patent Document 1 discloses a contraction process and a moving average used for image processing on pixel data obtained by converting an intermediate value between a minimum value and a maximum value of a radar reception signal to a threshold value and converting a signal below the threshold value to “0”. A clutter suppression device that can obtain a radar received image signal in which clutter is suppressed by performing processing is disclosed.

JP 2000-292525 A

Supervised by Takashi Yoshida “Revised Radar Technology” edited by The Institute of Electronics, Information and Communication Engineers, October 1, 1996, p87-3.6

  However, in the CFAR process, when the signal strength does not follow the assumed probability distribution, a threshold value different from the expected threshold value may be calculated. If target detection is performed based on a threshold value different from the expected threshold value, false detection (hereinafter referred to as “target false detection”) that detects clutter (for example, rainfall) as a target occurs, and detection accuracy is high. There is a problem of lowering.

  In the CFAR processing, when the spread of the target is large compared to the resolution as in the high resolution radar, the small target close to the large target is recognized as clutter and is not detected (hereinafter referred to as “target non-detection”). Occurs and the detection accuracy decreases.

  Furthermore, there are various types of CFAR processing, such as log CFAR or CA CFAR, depending on the calculation method, but since thresholds are calculated for all cells of the radar reception signal, the calculation of the target detection apparatus is performed. There is a problem that the scale becomes large.

  In addition, in the clutter suppression device described in Patent Document 1, since an intermediate value between the minimum value and the maximum value of the radar reception signal within a certain range is used as a threshold value, an appropriate threshold value cannot be obtained. Since it is necessary to calculate and binarize the threshold value from the suppressed radar reception image signal again by CFAR processing or the like, all of the above problems are inherent.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a target detection apparatus that can prevent erroneous detection and non-detection of a target despite a small calculation scale.

  In order to solve the above-described problem, the target detection apparatus according to the present invention has an attenuation level determined by an attenuation map among cells in a certain area indicated by a digital video signal obtained by quantizing an acquired radar reception signal. An attenuation unit that attenuates the signal strength of the set cell according to the attenuation level, and a threshold value for identifying the target and the clutter from the signal strength of the cell indicated by the digital video signal from the attenuation unit is calculated by the P tile method, Threshold calculation / binarization unit that binarizes cells in a certain area using the calculated threshold, and target detection is not required by a blank map for the values binarized by the threshold calculation / binarization unit The signal intensity of the cell set as the area is set to zero, and the binary digital video signal from the blank part is output as a binary digital video signal. Then, a contraction / expansion unit that performs a contraction process and an expansion process to determine a value within a certain region, and a clustering unit that performs clustering on the value determined by the contraction / expansion part and outputs it as detection target data And.

  According to the target detection device of the present invention, it is possible to provide a target detection device that can prevent erroneous detection and non-detection of a target even though the computation scale is small.

It is a block diagram which shows the structure of the target detection apparatus which concerns on Embodiment 1 of this invention. It is the schematic diagram which cut out a part in distance and the azimuth | direction direction from the radar received signal obtained with the antenna part 1 which concerns on Embodiment 1 of this invention, and changed the brightness according to signal strength. It is the figure which quantized the signal strength of the radar received signal shown in FIG. FIG. 4 is a histogram of the region shown in FIG. 3. It is the figure which binarized the area | region shown in FIG. 3 by P tile method. It is a figure which shows the state which is paying attention to arbitrary cells in the shrinkage | contraction process performed with the target detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the state which is paying attention to the arbitrary cells in the area | region after a clutter removal in the expansion process performed with the target detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the result of the expansion process performed with the target detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the 1st modification comprised by replacing the blank part and shrinkage | contraction / expansion part of the target detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the 2nd modification comprised by removing a blank part from the target detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the 3rd modification comprised by providing a blank part instead of the attenuation | damping part of the target detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the 4th modification comprised by providing an attenuation | damping part instead of the blank part of the target detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the 5th modification comprised by replacing the attenuation | damping part and blank part of the target detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the 6th modification comprised by removing an attenuation | damping part and a blank part from the target detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the 7th modification comprised by removing a contraction / expansion part from the target detection apparatus which concerns on Embodiment 1 of this invention. In the target detection apparatus according to Embodiment 2 of the present invention, it is a diagram in which a portion excluding cells in which the signal intensity in the region shown in FIG. In the target detection apparatus according to the second embodiment of the present invention, binarization is performed by the P tile method by excluding cells having a signal intensity of “0” from the region shown in FIG. It is a figure which shows the result of the shrinkage | contraction process performed with the target detection apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the result of the expansion process performed with the target detection apparatus which concerns on Embodiment 2 of this invention. In the target detection apparatus according to Embodiment 3 of the present invention, it is a diagram showing a state where the region shown in FIG. 3 is enlarged.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of a target detection apparatus according to Embodiment 1 of the present invention. This target detection apparatus includes an antenna unit 1, an A / D conversion unit 2, a coherent integration unit 3, a distance / azimuth thinning unit 4, an attenuation unit 5, an attenuation map unit 5a, a threshold calculation / binarization unit 6, and a calculation parameter unit. 6a, a blank part 7, a blank map part 7a, a contraction / expansion part 8, a contraction / expansion parameter part 8a, and a clustering part 9.

  The antenna unit 1 can be configured by a high-resolution antenna device such as ASDE (Airport Surface Detection Equipment). This aerial unit 1 acquires a radar reception signal indicating the airport surface in high definition and sends it to the A / D conversion unit 2. Note that a transmitter for transmitting a transmission wave for radiating toward the space by the antenna unit 1 and a receiver for receiving a received wave from a target or the like are well known, and detailed description thereof will be omitted.

  The A / D converter 2 quantizes the analog radar reception signal sent from the antenna unit 1 and converts it into a digital video signal. The digital video signal obtained by the conversion by the A / D conversion unit 2 is sent to the coherent integration unit 3.

  The coherent integrator 3 performs a coherent integration process on the digital video signal transmitted from the A / D converter 2. The digital video signal subjected to the coherent integration process in the coherent integration unit 3 is sent to the distance / azimuth thinning unit 4.

  The distance / azimuth thinning unit 4 thins out cells indicated by the digital video signal sent from the coherent integration unit 3 in the distance (range) direction and the azimuth (azimuth) direction. The digital video signal in which the cells are thinned by the distance / azimuth thinning unit 4 is sent to the attenuation unit 5.

  The attenuating unit 5 determines the signal strength of the cell whose attenuation level is set in the attenuation map stored in the attenuation map unit 5a among the cells indicated by the digital video signal sent from the distance / azimuth thinning unit 4. Attenuate. Here, in the attenuation map, for example, an attenuation level is set for a region where the signal intensity is always strong due to, for example, the vicinity of the antenna unit 1 or multipath of a transmission wave. Specifically, the signal strength of a cell having a large attenuation level approaches “0”. The digital video signal obtained by processing by the attenuation unit 5 is sent to the threshold value calculation / binarization unit 6.

  The threshold value calculation / binarization unit 6 calculates a threshold value for identifying a target and a clutter from the signal strength of the cell indicated by the digital video signal sent from the attenuation unit 5, and uses this calculated threshold value to The binarization is performed to convert the signal intensity of “1” into “1” or “0”. The binarized digital video signal binarized by the threshold calculation / binarization unit 6 is sent to the blank unit 7.

  The blank unit 7 is a cell set as a blank in the blank map stored in the blank map unit 7a among the cells indicated by the binarized digital video signal sent from the threshold calculation / binarization unit 6. Is converted to zero (“0”). Here, a target detection unnecessary area such as a terminal building is set as a blank in the blank map. Specifically, “0” is set in the target detection unnecessary area of the blank map, and “1” is set in the target detection required area. The binarized digital video signal obtained by processing in the blank part 7 is sent to the contraction / expansion part 8.

  The contraction / expansion unit 8 refers to surrounding cells, performs contraction processing and expansion processing using the contraction parameters and expansion parameters stored in the contraction / expansion parameter unit 8a, and determines the value of the corresponding cell. The processing result in the contraction / expansion unit 8 is sent to the clustering unit 9 as a binary digital video signal.

  The clustering unit 9 clusters a region in which “1” continues in the distance direction or the azimuth direction among the cells indicated by the binarized digital video signal sent from the contraction / expansion unit 8 and outputs it as detection target data. To do.

  Next, the operation of the target detection apparatus according to Embodiment 1 configured as described above will be described. FIG. 2 is a schematic diagram in which a part of the distance and azimuth direction is cut out from the radar reception signal received by the antenna unit 1 and the brightness is changed according to the signal intensity. It shows that there are a plurality of clutters 13 in the vicinity. In FIG. 2, portions with high signal strength such as the aircraft 11, the vehicle 12, and some of the clutter 13 are shown bright, and noise portions with low signal strength are shown dark.

  The radar reception signal received by the antenna unit 1 is sent to the A / D conversion unit 2. The A / D converter 2 quantizes the radar reception signal sent from the antenna unit 1 to convert it into a digital video signal, and sends it to the coherent integrator 3. In order to simplify the description, the A / D conversion unit 2 converts an analog signal sent as a radar reception signal from the antenna unit 1 into digital data of 0 to 8.

  The coherent integrator 3 performs a coherent integration process on the digital video signal sent from the A / D converter 2. By performing the coherent processing, a digital video signal in which the difference in signal intensity between the target having the same phase and the noise component having the different phase is enlarged is generated and sent to the distance / azimuth thinning unit 4. Since the coherent integration process is well known, detailed description thereof is omitted.

  The distance / azimuth thinning unit 4 thins cells indicated by the digital video signal transmitted from the coherent integration unit 3 in the distance direction and the azimuth direction using a predetermined method. As a result, an appropriate amount of cells are selected for the subsequent processing and sent to the attenuator 5 as a digital video signal. In addition, since the thinning-out method is well known, description thereof is omitted.

  The attenuation unit 5 performs a process of bringing the signal strength of the digital video signal of a cell whose attenuation level is set to a large value in the attenuation map stored in the attenuation map unit 5a to “0”, and calculates a threshold value / binarization unit Send to 6.

  The threshold calculation / binarization unit 6 refers to the calculation parameter stored in the calculation parameter unit 6a, calculates the threshold by the P tile method according to the calculation parameter, and sets the cell exceeding the threshold to “1”, A cell that falls below the threshold value is converted to “0”, binarized, and sent to the blank section 7 as a binarized digital video signal.

  Here, threshold calculation using the P tile method will be described. FIG. 3 shows an example of a digital video signal input to the threshold value calculation / binarization unit 6. The signal intensity of the radar reception signal shown in FIG. 2 is quantized and expressed as a numerical value. Originally, the signal strength varies in the coherent integration unit 3 and the distance / orientation thinning unit 4, but in order to simplify the explanation, the signal strength of the radar reception signal shown in FIG. 2 is quantized as it is. Shall. In FIG. 3, the processing target is a fixed area, specifically, an area of 50 cells × 50 cells. Each cell contains quantized values of 0 to 8, and the cells whose signal intensity is attenuated to “0” by the attenuation unit 5 are shaded. In addition, the larger the numerical value shown inside the cell, the stronger the signal strength.

  The P tile method is applied to such a region. The P-tile method is a method generally used in the field of image processing, and creates a histogram of all cells in a region and uses a calculation parameter so that the upper P% exceeds the threshold. Set. FIG. 4 is a histogram of the region shown in FIG. In this histogram, for example, if the upper 10% is set to exceed the threshold, cells whose signal intensity is “5” or more exceed the threshold (the accumulation up to “4” is 84.52%, the accumulation up to “5” is 91.96%). Therefore, in this region, cells having a signal strength of “5” or higher are converted to “1”, and cells having a signal strength of “4” or lower are converted to “0” and sent to the blank section 7 as a binary digital video signal.

  The blank unit 7 converts the signal strength of the binarized digital video signal of the cell set as a blank in the blank map stored in the blank map unit 7 a to “0” and sends it to the contraction / expansion unit 8.

  Next, the contraction process and the expansion process performed in the contraction / expansion unit 8 will be described. FIG. 5 shows a binarized digital video signal input to the contraction / expansion unit 8 after the region shown in FIG. 3 is binarized by the P tile method and blank processing is performed. The area of 50 cells is binarized. At this time, cells considered to be targets are largely grouped, but an isolated clutter “1” exists around the cell. The contraction / expansion unit 8 removes such isolated clutter by contraction processing and expansion processing.

  Shrinkage processing is generally used in the field of image processing, and pays attention to an arbitrary cell in the region, and refers to surrounding cells according to the shrinkage parameter stored in the shrinkage / expansion parameter unit 8a. Determine the value of the cell of interest. Here, if at least one “0” exists in eight cells around the target cell, the target cell is converted to “0”. FIG. 6 is a diagram illustrating a state where attention is paid to an arbitrary cell (a cell with a circle) in the region in the contraction process. In this case, the cell of interest is “1”, but a cell of “0” exists in some of the surrounding eight cells, so the cell of interest is converted to “0”. Similar processing is applied to all cells in the region to remove isolated clutter.

  Next, the expansion process will be described. Although the isolated clutter is removed by the above-described contraction process, the cell lump indicating the target is also reduced at the same time. Therefore, by performing the expansion process, the cluster of cells that artificially show the target is returned to the original size.

  Expansion processing is also commonly used in the field of image processing. Contrary to contraction processing, attention is paid to an arbitrary cell, and surrounding cells according to the expansion parameters stored in the contraction / expansion parameter section 8a are selected. Convert to the same value as the cell of interest. Here, when the target cell is “1”, all the surrounding eight cells are converted to “1”. FIG. 7 is a diagram illustrating a state where attention is paid to an arbitrary cell (a cell with a circle) in the region where the clutter is removed by the contraction process. In this case, since the target cell is “1”, the surrounding cells are converted to “1” as a result of the expansion process. A similar process is applied to all the cells in the region, so that the cell cluster indicating the target can be returned to the original size. FIG. 8 is a diagram illustrating a result of the expansion process. In this way, the binary digital video signal from which clutter is removed is sent to the clustering unit 9.

  The clustering unit 9 performs a process of regarding a cell region in which “1” continues among cells indicated by the binarized digital video signal transmitted from the contraction / expansion unit 8 as one target (cluster). In addition, when a plurality of clusters are close to each other, processing for combining the clusters is performed. The result is output as detection target data. The detection target data output from the clustering unit 9 is generally displayed on a display unit after a tracking process or the like is performed. Since the handling of the detection target data is well known, a description thereof will be omitted.

  As described above, according to the target detection apparatus according to the first embodiment of the present invention, the threshold value is set so that the upper P% of the histogram of all the cells in the certain region exceeds the threshold value using the P tile method. Since binarization is performed, the probability that the target to be detected disappears is reduced, and target non-detection can be prevented. Further, since an isolated clutter erroneously detected as a target is erased by the contraction / expansion process, erroneous detection of the target can be prevented. Furthermore, since all cells in a certain area indicated by the radar received signal are collectively calculated and the threshold value is binarized, it is not necessary to individually calculate all the cells, and the calculation scale can be reduced. can do.

  In the target detection device described above, the blank part 7 is provided between the threshold value calculation / binarization part 6 and the contraction / expansion part 8, but as shown in FIG. 9 (first modification). A blank portion 7 may be provided between the contraction / expansion portion 8 and the clustering portion 9. According to this configuration, the contraction / expansion process is performed while the signal intensity of the target detection unnecessary area remains, but the signal intensity of the target detection unnecessary area can be set to “0” after the contraction / expansion process. The same effects as those of the target detection apparatus according to the first embodiment described above can be obtained.

  Moreover, in the target detection apparatus mentioned above, although the blank part 7 was provided and it was comprised so that the signal strength of the cell set to the blank might be converted into "0" with reference to a blank map, FIG. 10 (2nd It is also possible to remove the blank part 7 and the blank map part 7a and send the output of the threshold value calculation / binarization part 6 to the contraction / expansion part 8 as shown in FIG. According to this configuration, the contraction / expansion processing is performed while the signal intensity of the target detection unnecessary region remains, and the target detection unnecessary region may be detected as a large target. It is possible to output with a small operation scale with respect to the required subsequent block.

  Moreover, in the target detection apparatus mentioned above, since the process in the attenuation | damping part 5 and the blank part 7 is performing the similar process of changing signal intensity according to the setting of each map, FIG. 11 (3rd modification) A blank portion 7 is provided instead of the attenuation portion 5 as shown in FIG. 12, or an attenuation portion is provided instead of the blank portion 7 as shown in FIG. 12 (fourth modification), or FIG. As shown in (Modification), the damping part 5 and the blank part can be replaced. According to these configurations, by changing the setting of the attenuation map or the blank map, it is possible to obtain the same effect as that of the target detection device according to the first embodiment described above.

  Moreover, in the target detection apparatus mentioned above, as shown in FIG. 14 (6th modification), it can also comprise so that the attenuation | damping part 5 and the blank part 7 may be removed. According to this configuration, the threshold value calculation / binarization process is performed while the signal strength in the target detection unnecessary region and the strong signal strength in the vicinity of the antenna unit 1 remain, and erroneous target detection may occur. However, it is possible to output to a subsequent block that requires such detection target data with a small calculation scale.

  Further, in the target detection device described above, the contraction / expansion unit 8 is configured to execute both the contraction process and the expansion process, but can be configured to execute only one of the contraction process and the expansion process. . According to this configuration, it is possible to further prevent target misdetection when performing only the contraction process, and non-detection of the target when performing only the expansion process.

  Furthermore, as shown in FIG. 15 (seventh modified example), the contraction / expansion unit 8 can be removed, and the output of the blank unit 7 can be directly sent to the clustering unit 9. According to this configuration, the isolated clutter remains without being removed, but can be output with a small calculation scale to a subsequent block that requires such detection target data.

  The replacement of the respective parts (processes) shown in the first to seventh modified examples described above can be used in combination, so that the respective effects can be combined.

Embodiment 2. FIG.
The target detection apparatus according to the second embodiment of the present invention employs a method different from that of the first embodiment as a threshold value calculation method using the P tile method. This target detection apparatus is the same as the target detection apparatus according to the first embodiment described above, except for the operation of the threshold calculation / binarization unit 6. In the following, the description will focus on the parts different from the first embodiment.

  Similarly to the first embodiment, the threshold calculation / binarization unit 6 is input with a digital video signal in which there exists a cell whose signal intensity is attenuated to “0” by the attenuation unit 5 as shown in FIG. The The threshold value calculation / binarization unit 6 creates a histogram by excluding cells having a signal intensity of “0” from the cells indicated by the input digital video signal. FIG. 16 is a histogram of the area shown in FIG. 3 excluding the “0” cell. In this histogram, if the upper 10% is set to exceed the threshold, cells whose signal intensity is “6” or more exceed the threshold (the accumulation up to “5” is 89.54%, and the accumulation up to “6” is 94. .02%). Therefore, cells having a signal strength of “6” or more are converted to “1”, and cells having a signal intensity of “5” or less are converted to “0”, and sent to the contraction / expansion unit 8 as a binary digital video signal.

  FIG. 17 is a diagram showing a binarized digital video signal binarized by the P-tile method by removing blanks (“0” cells) from the region shown in FIG. This binarized digital video signal is sent to the contraction / expansion unit 8 through the blank unit 7. Unlike the case of the first embodiment, the area of “1” is reduced and the target is also reduced, but the isolated clutter is removed. FIG. 18 is a diagram showing a binarized digital video signal subjected to the same contraction processing as in the first embodiment, and FIG. 19 is a diagram illustrating a binarized digital video signal subjected to expansion processing.

  As described above, according to the target detection apparatus according to the second embodiment, the threshold for identifying the target and the clutter is increased, so that the possibility of non-detection of the small target is increased, but erroneous detection of the target is performed. It can be further reduced.

Embodiment 3 FIG.
The target detection apparatus according to the third embodiment of the present invention employs a method different from the first and second embodiments as a threshold value calculation method using the P tile method. This target detection apparatus is the same as the target detection apparatus according to the first embodiment described above, except for the operation of the threshold calculation / binarization unit 6. In the following, the description will focus on the parts different from the first embodiment.

  Similarly to the first embodiment, the threshold calculation / binarization unit 6 is input with a digital video signal in which there exists a cell whose signal intensity is attenuated to “0” by the attenuation unit 5 as shown in FIG. The Here, when the target exists at the end of the region shown in FIG. 3, it is expected that the cell indicating the target will be “0” due to the contraction / expansion processing. Enlarge the area.

  FIG. 20 is a diagram illustrating a state in which the region illustrated in FIG. 3 is enlarged. In order to simplify the description, the signal strength of the enlarged portion is omitted. If a histogram is created for this enlarged area in the same manner as in the first or second embodiment, the threshold value of the fixed area of 50 cells × 50 cells shown in FIG. 3 may increase. Therefore, a histogram is created using a predetermined percentage of cells from the lower signal strength of the enlarged region. Here, for example, a histogram is created using 95% of cells. After calculating a threshold value for this histogram in the same manner as in the first embodiment, binarization is performed only for a certain area shown in FIG. 3, so that the target existing at the end of the area easily exceeds the threshold value. . Thereafter, blanking, contraction / expansion, and clustering are sequentially performed to output detection target data.

  As described above, according to the target detection apparatus according to the third embodiment, since the area to be referred to when the threshold value is calculated is enlarged, it is possible to prevent non-detection of the target existing at the end of the area.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  DESCRIPTION OF SYMBOLS 1 Antenna part, 2 A / D conversion part, 3 Coherent integration part, 4 Distance / direction thinning part, 5 Attenuation part, 5a Attenuation map part, 6 Threshold calculation / binarization part, 6a Calculation parameter part, 7 Blank part, 7a Blank map part, 8 contraction / expansion part, 8a contraction / expansion parameter part, 9 clustering part.

Claims (9)

An attenuation unit for attenuating the signal strength of a cell whose attenuation level is set by an attenuation map among the cells in a certain area indicated by the digital video signal obtained by quantizing the acquired radar reception signal according to the attenuation level; ,
A threshold value for discriminating a target and clutter is calculated from the signal strength of the cell indicated by the digital video signal from the attenuation unit by the P-tile method, and the cells in the fixed area are binarized using the calculated threshold value. A threshold calculation / binarization unit to perform,
A blank unit that zeros the signal intensity of a cell set as a target detection unnecessary area by a blank map with respect to the value binarized by the threshold calculation / binarization unit, and outputs it as a binarized digital video signal When,
A contraction / expansion unit that performs a contraction process and an expansion process on the binarized digital video signal from the blank part to determine a value in the predetermined region;
A target detection apparatus comprising: a clustering unit that performs clustering on values determined by the contraction / expansion unit and outputs the result as detection target data. When the threshold value calculation / binarization unit calculates the threshold value by the P tile method, the threshold value calculation / binarization unit creates a histogram excluding cells in which the signal strength is attenuated to zero in the attenuation unit, and determines the threshold value based on the histogram. The target detection apparatus according to claim 1, wherein: When the threshold value calculation / binarization unit calculates the threshold value by the P tile method, the threshold value calculation / binarization unit expands a certain area where the cell indicated by the digital video signal sent from the attenuation unit exists, and determines a predetermined value from the lower signal strength. The target detection apparatus according to claim 1, wherein a histogram is created using percentage cells, and a threshold is determined based on the histogram. A threshold for identifying a target and a clutter is calculated by the P-tile method from the signal strength of a cell in a certain area indicated by the digital video signal obtained by quantizing the acquired radar reception signal, and the calculated threshold is A threshold calculation / binarization unit that binarizes the cells in the fixed region using,
A contraction / expansion unit for performing a contraction process and an expansion process on a value binarized by the threshold value calculation / binarization unit to determine a value in the predetermined region;
Among the cells indicated by the digital video signal having the value determined by the contraction / expansion unit, a blank unit for setting the signal intensity of the cell set as the target detection unnecessary region by the blank map to zero,
A target detection apparatus comprising: a clustering unit configured to perform clustering on the cell values output from the blank unit and output as detection target data. A threshold for identifying a target and a clutter is calculated by the P-tile method from the signal strength of a cell in a certain area indicated by the digital video signal obtained by quantizing the acquired radar reception signal, and the calculated threshold is A threshold calculation / binarization unit that binarizes the cells in the fixed region using,
A contraction / expansion unit for performing a contraction process and an expansion process on a value binarized by the threshold value calculation / binarization unit to determine a value in the predetermined region;
A target detection apparatus comprising: a clustering unit that clusters the values binarized by the contraction / expansion unit and outputs the result as detection target data. 6. The contraction / expansion unit performs only contraction processing on the value binarized by the threshold value calculation / binarization unit, according to claim 1. Target detection device. 6. The contraction / expansion unit performs only an expansion process on the value binarized by the threshold calculation / binarization unit, according to any one of claims 1 to 5. Target detection device. A threshold for identifying a target and a clutter is calculated by the P-tile method from the signal strength of a cell in a certain area indicated by the digital video signal obtained by quantizing the acquired radar reception signal, and the calculated threshold is A threshold calculation / binarization unit that binarizes the cells in the fixed region using,
A blank unit that zeros the signal intensity of a cell set as a target detection unnecessary area by a blank map with respect to the value binarized by the threshold calculation / binarization unit, and outputs it as a binarized digital video signal When,
A target detection apparatus comprising: a clustering unit configured to perform clustering on the values of the binary digital video signal from the blank unit and output the detection target data. A threshold for identifying a target and a clutter is calculated by the P-tile method from the signal strength of a cell in a certain area indicated by the digital video signal obtained by quantizing the acquired radar reception signal, and the calculated threshold is A threshold calculation / binarization unit that binarizes the cells in the fixed region using,
A target detection apparatus comprising: a clustering unit that performs clustering based on the values binarized by the threshold calculation / binarization unit and outputs the data as detection target data.

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