Method and device for processing echo signal, radar device and echo signal processing program

• US 8,593,335 B2
• Filed: 01/25/2011
• Issued: 11/26/2013
• Est. Priority Date: 02/23/2010
• Status: Expired due to Fees

• Current Assignee: Furuno Electric Co, Ltd
• Original Assignee: Furuno Electric Co, Ltd
• Inventors: Nakagawa, Kazuya
• Primary Examiner(s): Keith, Jack W
• Assistant Examiner(s): BYTHROW, PETER M
• Application Number:
  US13/013,218
• Publication Number:
  US 20110205104A1
• Time in Patent Office: 1,036 Days
• Field of Search: 342/145, 342/147, 342158-164, 342/175, 342/176, 342/179, 342/189, 342195-197
• US Class Current: 342/159
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: G01S 13/937 of marine craft
• CPC Class Codes: G01S 7/22 Producing cursor lines and indicia by electronic means
• CPC Class Codes: G01S 7/414 Discriminating targets with respect to background clutter
• CPC Class Codes: G06T 2207/10044 Radar image
• CPC Class Codes: G06T 2207/20192 Edge enhancement; Edge preservation
• CPC Class Codes: G06T 2207/30212 Military
• CPC Class Codes: G06T 5/003 Deblurring; Sharpening vibration or motion blur correction for cameras comprising an electronic image sensor H04N23/682
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 5/73 Deblurring; Sharpening

Abstract

A method includes inputting an echo signal from an antenna for discharging an electromagnetic wave to a predetermined area and receiving an echo signal reflected on a target object, outputting a level of the echo signal from every location so as to associate the level with a distance from the antenna in an azimuth direction where the electromagnetic wave is discharged, calculating a degree of change in the level of the echo signal from mutually adjacent locations among all the locations concerned, performing edge emphasis processing for the level of the echo signal in the azimuth direction based on the degree of change and outputting an edge-emphasized echo signal, and performing scan-to-scan correlation processing to calculate a correlation value of the echo signals of two or more scans using the edge-emphasized echo signals, where the echo signals from the entire predetermined area is used as one scan.

Claims

1. An echo signal processing device, comprising:

an echo signal input module to which an echo signal from an antenna for discharging an electromagnetic wave to a predetermined area and receiving an echo signal reflected on a target object is inputted;

an echo signal level detector that outputs a level of the echo signal from every location so as to associate the level with a distance from the antenna in a direction where the electromagnetic wave is discharged;

a level change degree calculator that calculates a degree of change in the level of the echo signal from mutually adjacent locations among all the locations concerned; and

an edge emphasis processor that performs edge emphasis processing for the level of the echo signal in the direction based on the degree of change and outputs an edge-emphasized echo signal.

2. The echo signal processing device of claim 1, further comprising:

a correlation processor that performs scan-to-scan correlation processing to calculate a correlation value of the echo signals of two or more scans using the edge-emphasized echo signals, where the echo signals from the entire predetermined area is used as one scan.

3. The echo signal processing device of claim 2, wherein the scan-to-scan correlation processing includes processing to calculate the correlation value of the echo signals based on a correlation between a first echo signal caused by the electromagnetic wave discharged from the antenna at a first time point, and the edge-emphasized echo signal outputted from the edge emphasis processor for the level of the echo signal observed as an observation signal at substantially the same location as the first echo signal, caused by the electromagnetic wave discharged from the antenna at a second time point different from the first time point.

4. The echo signal processing device of claim 2, wherein the scan-to-scan correlation processing includes processing to calculate the correlation value of the echo signals based on a correlation between a first edge-emphasized echo signal outputted from the edge emphasis processor for a level of a first echo signal caused by the electromagnetic wave discharged from the antenna at a first time point, and a second edge-emphasized echo signal outputted from the edge emphasis processor for the level of the echo signal observed as an observation signal at substantially the same location as the first echo signal, caused by the electromagnetic wave discharged from the antenna at a second time point different from the first time point.

5. The echo signal processing device of claim 2, further comprising a memory that stores an output signal from the correlation processor;

wherein the scan-to-scan correlation processing includes processing to calculate the correlation value of the echo signals based on a correlation between a first edge-emphasized echo signal outputted from the edge emphasis processor for the level of a first echo signal caused by the electromagnetic wave discharged from the antenna at a first time point, and a signal after the past scan-to-scan correlation processing stored in the memory.

6. The echo signal processing device of claim 2, wherein the scan-to-scan correlation processing includes processing to calculate the correlation value of the echo signals based on a correlation between a first echo signal caused by the electromagnetic wave discharged from the antenna at a first time point, and the edge-emphasized echo signal outputted from the edge emphasis processor for the level of the echo signal observed as an observation signal at substantially the same location as the first echo signal, caused by the electromagnetic wave discharged from the antenna at a second time point different from the first time point.

7. The echo signal processing device of claim 2, wherein the scan-to-scan correlation processing includes processing to calculate the correlation value of the echo signals based on a correlation between a first edge-emphasized echo signal outputted from the edge emphasis processor for a level of a first echo signal caused by the electromagnetic wave discharged from the antenna at a first time point, and a second edge-emphasized echo signal outputted from the edge emphasis processor for the level of the echo signal observed as an observation signal at substantially the same location as the first echo signal, caused by the electromagnetic wave discharged from the antenna at a second time point different from the first time point.

8. The echo signal processing device of claim 2, further comprising a memory for storing an output signal from the correlation processor;

wherein the scan-to-scan correlation processing includes processing to calculate the correlation value of the echo signals based on a correlation between a first edge-emphasized echo signal outputted from the edge emphasis processor for the level of a first echo signal caused by the electromagnetic wave discharged from the antenna at a first time point, and a signal after the past scan-to-scan correlation processing stored in the memory.

9. The echo signal processing device of claim 2, wherein the degree of change in the echo signal is a difference of the levels of the echo signals at mutually adjacent locations.

10. The echo signal processing device of claim 2, wherein the degree of change in the echo signal is a differential value calculated by differentiating to an envelope formed of the level of the echo signal, with respect to a direction.

11. The echo signal processing device of claim 2, the degree of change in the echo signal is a value calculated by weighted addition processing for the level of the echo signal at the location concerned and its surrounding locations.

12. The echo signal processing device of claim 2, wherein the edge emphasis processing includes processing for multiplying the level of the echo signal of each of the locations by a coefficient determined based on the degree of change.

13. The echo signal processing device of claim 2, wherein the edge emphasis processing is performed when the degree of change in the echo signal exceeds a predetermined threshold.

14. The echo signal processing device of claim 2, further comprising a display that displays an image of the target object based on an output signal of the correlation processor.

15. A radar device, comprising:

the echo signal processing device of claim 2; and

the antenna for rotating while discharging the electromagnetic wave and receiving the echo signal for every direction.

16. A radar device, comprising:

the echo signal processing device of claim 14; and

the antenna for rotating while discharging the electromagnetic wave and receiving the echo signal for every direction.

21. The device of claim 1, where the edge emphasis processor selects an edge area of the target object for emphasis based on the degree of change and performs edge emphasis processing on the selected edge area.

17. A method of processing an echo signal, comprising:

inputting an echo signal from an antenna for discharging an electromagnetic wave to a predetermined area and receiving an echo signal reflected on a target object;

outputting a level of the echo signal from every location so as associate the level with a distance from the antenna in a direction where the electromagnetic wave is discharged;

calculating, with a processor, a degree of change in the level of the echo signal from mutually adjacent locations among all the locations concerned; and

performing, with a processor, edge emphasis processing for the level of the echo signal in the azimuth direction based on the degree of change and outputting an edge-emphasized echo signal.

18. A method of processing an echo signal of claim 17, further comprising:

performing, with a processor, scan-to-scan correlation processing to calculate a correlation value of the echo signals of two or more scans using the edge-emphasized echo signals, where the echo signals from the entire predetermined area is used as one scan.

22. The method of claim 17, said performing edge emphasis processing including selecting an edge area of the target object for emphasis based on the degree of change and performing edge emphasis processing on the selected edge area.

19. A non-transitory computer-readable medium having embodied thereon instructions representing an echo signal processing program, which, when executed by a processor, causes the processor to perform steps comprising:

inputting an echo signal from an antenna for discharging an electromagnetic wave to a predetermined area and receiving an echo signal reflected on a target object;

outputting a level of the echo signal from every location so as to associate the level with a distance from the antenna in an azimuth direction where the electromagnetic wave is discharged;

calculating a degree of change in the level of the echo signal from mutually adjacent locations among all the locations concerned; and

performing edge emphasis processing for the level of the echo signal in the direction based on the degree of change and outputting an edge-emphasized echo signal.

20. The medium of claim 19, the steps further comprising:

performing scan-to-scan correlation processing to calculate a correlation value of the echo signals of two or more scans using the edge-emphasized echo signals, where the echo signals from the entire predetermined area is used as one scan.