METHOD AND DEVICE FOR PROCESSING ECHO SIGNAL, RADAR DEVICE AND ECHO SIGNAL PROCESSING PROGRAM

• US 20110205104A1
• Filed: 01/25/2011
• Published: 08/25/2011
• Est. Priority Date: 02/23/2010
• Status: Active Grant

• Current Assignee: Furuno Electric Co, Ltd
• Original Assignee: Furuno Electric Co, Ltd
• Inventors: NAKAGAWA, Kazuya
• Granted Patent: US 8,593,335 B2
• Time in Patent Office: Days
• US Class Current: 342/145
• 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 5/50 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 detecting module for outputting 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 calculating module for calculating a degree of change in the level of the echo signal from mutually adjacent locations among all the locations concerned; and

an edge emphasis processing module for 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.

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

a correlation processing module for 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 1, 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 processing module 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 1, 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 processing module 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 processing module 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 1, further comprising a memory module for storing an output signal from the correlation processing module;

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 processing module 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 module.

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 processing module 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 processing module 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 processing module 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 module for storing an output signal from the correlation processing module;

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 processing module 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 module.

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 module for displaying an image of the target object based on an output signal of the correlation processing module.

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.

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 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 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 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.

19. An echo signal processing program, executable by a computer, the program 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. An echo signal processing program, executable by a computer of claim 19, the program 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.