Target detection device and detection image processing method

Abstract

To provide a target detection device and a detection image processing method that can reduce the amount of data on a detection image to be output with respect to an image processing technique in outputting the detection image from the target detection device to external electronic equipment.SOLUTION: A radar device 1 is characterized in that: an initial detection image generation part 11 generates an initial detection image consisting of raster-form image data based upon a reflected wave; a target detection part 12 detects an image of a target from the initial detection image; a target image generation part 13 generates a target image based upon an image of the detected target; a noise image generation part 15 generates a noise image by subtracting the image of the target from the initial detection image; and an output part 14 outputs the target image and noise image separately to external electronic equipment.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a target object detection device and a detection image processing method, and more particularly to an image processing technique for outputting a detection image from a target object detection device to an external electronic device. [Background technology]

[0002] Conventionally, a detection image (analog signal) consisting of a radar echo received by a radar antenna is output from the radar antenna to an interswitch, and the interswitch is switched to display the image on a desired display device within the same ship (see, for example, Patent Document 1). However, with the recent progress in digitalization, detection images converted into digital data are now transmitted to external electronic devices (for example, personal computers, radar antennas, smartphones, etc.) using wired networks such as Ethernet (registered trademark) or wireless networks such as wireless LAN. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-38998 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the data of detection images, which was previously output in analog form, was sampled and digitized while maintaining the same resolution, there was a problem that the amount of data became enormous. To solve this problem, the raster data obtained by digitization was compressed using a compression algorithm and output, but this method still produced a large amount of data, and the load required to restore the compressed data was large, making it difficult to receive on low-spec display devices such as smartphones.

[0005] Therefore, the present invention relates to an image processing technology when outputting a detection image from a target detection device to an external electronic device, and aims to provide a target detection device and a detection image processing method that can reduce the amount of data of the output detection image. [Means for solving the problem]

[0006] In order to solve the above problem, the invention described in claim 1 is a target object detection device that generates a detection image based on a reflected wave from a target object, and is characterized in that it comprises an initial detection image generation means for generating an initial detection image consisting of raster-format image data based on the reflected wave, a target object detection means for detecting an image of the target object from the initial detection image, a target object image generation means for generating a target image based on the detected image of the target object, a noise image generation means for generating a noise image by subtracting the image of the target object from the initial detection image, and an output means for outputting the target image and the noise image separately to an external electronic device.

[0007] The invention described in claim 2 is a detection image processing method in a target object detection device that generates a detection image based on a reflected wave from a target object, characterized in that an initial detection image consisting of raster-format image data is generated based on the reflected wave, an image of the target object is detected from the initial detection image, a target image is generated based on the detected image of the target object, a noise image is generated by subtracting the image of the target object from the initial detection image, and the target image and the noise image are output separately to an external electronic device. Effect of the Invention

[0008] According to the inventions described in claims 1 and 2, a target image relating to the image of the target and a noise image relating to noise are generated from the initial detection image, and the target image and noise image are output separately to an external electronic device. This makes it possible to reduce the signal strength when outputting at least the noise image, thereby making it possible to reduce the amount of transmitted data compared to when all information (target and noise) is output using the first detection image in raster format. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing a schematic configuration of a radar system according to an embodiment of the present invention; [Diagram 2] 1 is a block diagram showing a schematic configuration of a radar device according to an embodiment of the present invention; [Diagram 3] 5 is a process diagram showing a procedure of detection image processing performed in the radar device according to the embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the present invention will be described based on the illustrated embodiment.

[0011] 1 is a schematic diagram showing a schematic configuration of a radar system using a radar device (target object detection device) 1 according to an embodiment of the present invention. The radar system includes the radar device 1, a LAN cable 2, a HUB 3, and electronic equipment 4.

[0012] The radar device 1 is an embodiment of the target object detection device of the present invention, and is a mechanism for transmitting a radar signal and receiving a radar echo, which is a reflected signal of the radar signal, and detecting targets existing around the radar device itself based on the radar echo. In this embodiment, the radar device 1 will be described by taking as an example a case where it is mounted on a ship.

[0013] The LAN cable 2 is a cable for connecting devices to each other to configure an in-house network such as Ethernet (registered trademark). In this embodiment, the LAN cable 2 is used to connect between the radar device 1 and the HUB 3, and between the HUB 3 and the electronic device 4.

[0014] The HUB 3 is a device with an array of terminals (ports) for connecting multiple LAN cables 2, and enables communication between them by transmitting signals coming from one LAN cable 2 to other LAN cables 2.

[0015] The electronic device 4 is a device that displays an image output from the output unit (output means) 14 of the radar device 1. The type of the electronic device 4 is not particularly limited, and examples thereof include a personal computer and a smartphone. Note that, in the present embodiment, an example is described in which the electronic device 4 is installed in the ship on which the radar device 1 is mounted, and the radar device 1 and the electronic device 4 are connected using wired communication, but the radar device 1 and the electronic device 4 may also be connected using wireless communication. In addition, a satellite communication device may be connected to the radar device 1 so that a detection image can be transmitted to the electronic device 4 located in a location separate from the ship on which the radar device 1 is mounted.

[0016] 2 is a block diagram showing a schematic configuration of a radar device 1 according to this embodiment. The radar device 1 has a radar antenna 16, a transmitting / receiving unit 17, an AD conversion section 18, an initial detection image generating section (initial detection image generating means) 11, a target detection section (target detection means) 12, a target image generating section (target image generating means) 13, an output section 14, and a noise image generating section (noise image generating means) 15.

[0017] The radar antenna 16 is a transceiver that has the function of wirelessly transmitting (in other words, radiating) a radar signal as a pulsed radio wave and capturing radar echoes (specifically, reflected signals of the radar signal), which are reflected waves of the transmitted / radiated radio waves.

[0018] The transmission / reception unit 17 is a communication circuit having a function of generating a radar signal, transmitting the generated radar signal via the radar antenna 16, and receiving a radar echo, which is a reflected signal of the transmitted radar signal, via the radar antenna 16. The transmission / reception unit 17 transmits the radar signal at a predetermined time interval (specifically, a time interval shorter than the horizontal rotation period of the radar antenna 16) and receives and outputs the radar echo.

[0019] The AD conversion unit 18 converts the radar echo supplied from the transmission / reception unit 17 from an analog signal to a digital signal and outputs it as an echo signal. Note that the echo signal output from the AD conversion unit 18 may be subjected to a predetermined signal processing as necessary. Specifically, for example, a sensitivity adjustment process may be performed on the echo signal.

[0020] In the radar device 1 according to this embodiment, detection image processing as shown in Fig. 3 is performed based on the reflected waves from the target. First, an initial detection image generating unit 11 generates an initial detection image consisting of raster-format image data based on the reflected waves, and a target detection unit 12 detects target images 1 to 3 from the initial detection image (step 1). Here, the raster-format image data refers to image data in which a plane is divided into a grid and information is provided for each square cell (pixel). In the radar device 1, a detection image (analog signal) consisting of radar echoes, which are reflected waves, is converted into a digital signal, and image data generated based on the echo data obtained from the digital signal is raster-format image data, which corresponds to the initial detection image.

[0021] Next, the generation of the noise image and the generation of the target image are carried out in parallel.

[0022] The noise image is generated by subtracting the target images 1 to 3 from the initial detection image in the noise image generating unit 15 (step 2). The data format of the noise image is a raster format.

[0023] Examples of noise contained in a noise image include clutter caused by sea surface reflection, land reflection, and rain / snow reflection. Usually, noise such as clutter is removed as unnecessary echoes. However, in special applications, such as when measuring ocean currents by observing the sea surface conditions and optimizing navigation, or in the case of automatic ship navigation, it is necessary to actively utilize noise. In such cases, it is effective to generate and output a noise image.

[0024] The target image is generated in the target image generating unit 13 based on the target images 1 to 3 detected from the initial detection image (step 4).

[0025] The data format and specific generation method of the target image are not particularly limited. For example, target images 1 to 3 may be detected from the initial detection image and used as a target image as is, thereby generating a target image made of raster format image data. Also, edges of target images 1 to 3 detected from the initial detection image may be detected, and a target image made of vector format image data may be generated based on the detected edges. Also, a target image made of raster format image data may be generated for a desired target image among target images 1 to 3, by using the target image as is, and a target image made of vector format image data based on edges may be generated for the other target images.

[0026] Among them, it is preferable to use a target image formed of vector-format image data based on the edges of the target image, in order to reduce the amount of data to be transmitted to the external electronic device 4. Since the image quality of vector-format image data is not lost even when it is enlarged or reduced, By using the target image, it is possible to support electronic devices 4 with a wide variety of resolutions, such as smartphones.

[0027] A case where both a raster-format target image and an edge-based vector-format target image are generated for the image of a desired target and an edge-based vector-format target image for the image of the other target is assumed to be a case where it is desired to detect small targets such as fishing nets, pitting, and bonden as well as major targets such as ships. In this case, an edge-based vector-format target image is generated for the image of the major target, and a raster-format target image is generated for the image of the small target. This is because the image of the small target is unclear and the edges are difficult to detect, so it tends to be omitted from the edge-based vector-format target image. Raster-format image data includes detailed data on color shading, i.e., brightness, so that if a raster-format target image is generated for the image of the small target, it becomes possible to detect the small target. Moreover, by making the image of the small target a raster-format target image, it becomes possible to reduce the amount of transmission data compared to the case where a raster-format target image is generated and output for all the images of the target.

[0028] The noise image and the target image obtained in the above manner are output from the output unit 14 to the external electronic device 4 separately (steps 3 and 5). This makes it possible to reduce the amount of data to be transmitted. The reason for this will be explained using the A-scope waveform in FIG.

[0029] 3, data relating to target images 1 to 3 form maximum values ​​(peaks) 1 to 3 in the A-scope waveform 1, and have a maximum signal strength of approximately 8 bits. This indicates that a signal strength of approximately 8 bits is required to output data including target images 1 to 3 to an external electronic device 4.

[0030] On the other hand, the data related to noise forms the A-scope waveform 2, i.e., the remaining waveform portion obtained by removing peaks 1 to 3 from the A-scope waveform 1, and has a signal strength of about 4 bits or less. This indicates that a signal strength of about 4 bits is sufficient to output the data related to noise to the external electronic device 4.

[0031] In other words, when the data relating to the target images 1 to 3 and the data relating to noise are output together, they must be output at a signal strength of approximately 8 bits throughout. However, by outputting the data relating to the target images 1 to 3 and the data relating to noise separately, the dynamic range can be shortened to a signal strength of approximately 4 bits when outputting the noise image data, thereby making it possible to reduce the total amount of transmitted data.

[0032] The electronic device 4 that receives the noise image and the target image selects whether to display both the received noise image and the target image, only the target image, or only the noise image, depending on its processing capability and necessity. Fig. 3 shows an A-scope waveform 3 of the electronic device 4 when displaying both the noise image and the target image.

[0033] As described above, by generating a target image relating to the image of the target and a noise image relating to noise from the initial detection image and outputting the target image and noise image separately to an external electronic device, the signal strength when outputting at least the noise image can be reduced, making it possible to reduce the amount of transmitted data compared to when all information (target and noise) is output using the first detection image in raster format.

[0034] Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above embodiment, and even if there are design changes within the scope of the gist of the present invention, they are included in the present invention. For example, the above embodiment has been described using a radar device for a ship as an example. However, the target detection device of the present invention is not limited to a radar device for ships, but may be, for example, a radar device mounted on a vehicle, or a sonar that uses sound waves to detect targets. [Explanation of symbols]

[0035] 1. Radar equipment (target detection equipment) 11 Initial detection image generation unit (initial detection image generation means) 12 Target detection unit (target detection means) 13 Target image generating unit (target image generating means) 14 Output section (output means) 15 Noise image generating unit (noise image generating means) 16 Radar Antenna 17 Transmitting and receiving unit 18 AD conversion section 2 LAN cable 3 HUB 4 Electronic equipment

Claims

1. A target detection device that generates a detection image based on a reflected wave from a target, an initial detection image generating means for generating an initial detection image made of image data in a raster format based on the reflected wave; a target detection means for detecting an image of a target from the initial detection image; a target image generating means for generating a target image based on an image of the detected target; a noise image generating means for generating a noise image by subtracting an image of the target from the initial detection image; an output means for outputting the target image and the noise image separately to an external electronic device; A target detection device comprising:

2. A detection image processing method for a target detection device that generates a detection image based on a reflected wave from a target, comprising: generating an initial detection image consisting of raster-format image data based on the reflected waves; Detecting an image of a target from the initial detection image; generating a target image based on the detected image of the target; generating a noise image by subtracting the image of the target from the initial detection image; outputting the target image and the noise image separately to an external electronic device; A detection image processing method comprising the steps of:

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