Method and system for ladar transmission with interline detouring for dynamic scan patterns

• US 10,215,848 B2
• Filed: 01/08/2018
• Issued: 02/26/2019
• Est. Priority Date: 08/15/2014
• Status: Active Grant

• Current Assignee: AEye, Inc.
• Original Assignee: AEye, Inc.
• Inventors: Dussan, Luis Carlos
• Primary Examiner(s): Abraham, Samantha K
• Application Number:
  US15/864,511
• Publication Number:
  US 20180143300A1
• Time in Patent Office: 414 Days
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/484 Transmitters
• CPC Class Codes: G01S 7/4861 Circuits for detection, sampling, integration or read-out
• CPC Class Codes: G01S 7/499 using polarisation effects

Abstract

Various embodiments are disclosed for improved scanning ladar transmission, including but not limited to an example embodiment where a dynamic scan pattern for a scanning ladar transmission system includes interline skipping and detouring.

Claims

1. An apparatus comprising:

a scanning ladar transmission system configured to transmit a plurality of ladar pulses toward a plurality of range points based on a shot list, wherein the shot list defines a dynamic scan pattern that includes interline detouring, the shot list comprising an ordered set of the range points, wherein the range points have coordinates defined by a first axis and a second axis, wherein the range points include a first range point and a second range point in a first row along the first axis and a third range point in a second row along the first axis, wherein the third range point is located between the first and second range points with reference to the second axis;

wherein the scanning ladar transmission system further comprises a processor, the processor configured to sort a plurality of range points into the ordered set for the shot list based on a parameter indicative of an amount of time needed by the scanning ladar transmission system to perform an interline detour, wherein the interline detour parameter is indicative of an amount of time needed by the scanning ladar transmission system to (i) scan from a current row to another row, (ii) scan to a range point in the another row, and (iii) return to the current row; and

wherein the processor is further configured to sort the third range point into the ordered set to fall between the first and second range points in response to a determination that an amount of time needed by the scanning ladar transmission system to (1) scan from the first range point to the second range point after transmitting a ladar pulse toward the first range point, (2) transmit a ladar pulse toward the third range point, and (3) scan from the third range point to the second range point is less than the interline detour parameter.

2. The apparatus of claim 1 wherein the processor is further configured to (1) apply a range point down selection algorithm to data representative of a field of view for the scanning ladar transmission system, and (2) select a subset of range points within the field of view for targeting by the scanning ladar transmission system based on the applied range point down selection algorithm, wherein the selected subset of range points serve as range points in the shot list.

3. An apparatus comprising:

a scanning ladar transmission system configured to transmit a plurality of ladar pulses toward a plurality of range points in accordance with a dynamic scan pattern that includes interline detouring;

wherein the scanning ladar transmission system comprises a processor and a beam scanner, the beam scanner comprising a mirror;

wherein the processor is configured to process a plurality of range points to create an ordered set of range points, each range point having an associated row identifier and an associated column identifier that together define a mirror scan position, the ordered set serving as a shot list for the scanning ladar transmission system, wherein the processor, as part of the processing operation, is further configured to;

determine, based on a parameter indicative of an amount of time needed by the scanning ladar transmission system to (i) scan from a current row to another row, (ii) scan to a range point in the another row, and (iii) return to the current row, whether any interline detours are to be used for the scanning ladar transmission system to target the range points;

sort the range points into the ordered set based on the interline detour determinations; and

in response to a determination that an interline detour is to be used, tag the shot list with interline detour identifier within the ordered set at a location where the interline detour is to be performed; and

wherein the beam scanner is configured to scan the mirror to a plurality of mirror scan positions in accordance with the shot list including any interline detour identifiers present therein to target the range points via the dynamic scan pattern, wherein the mirror scan positions define where the scanning ladar transmission system is targeted; and

wherein the scanning ladar transmission system is further configured to transmit, via the scanning mirror, a plurality of ladar pulses toward the range points of the shot list in accordance with the dynamic scan pattern.

4. The apparatus of claim 3 wherein the processor, as part of the processing operation, is further configured to:

for each of a plurality of pairs of range points, (1) compute a data value as a function of the row and column identifiers associated with the range points of the pair such that the computed data value is indicative of an amount of time needed by the scanning ladar transmission system to scan from a first range point of the pair to a second range point of the pair, and (2) perform the interline detour determinations based on the computed data values as compared to the parameter indicative of the amount of time needed by the scanning ladar transmission system to (i) scan from a current row to another row, (ii) scan to a range point in the another row, and (iii) return to the current row.

5. The apparatus of claim 4 wherein the mirror comprises a first mirror and a second mirror, wherein the beam scanner is further configured to (1) scan the first mirror with respect to a first axis for targeting the scanning ladar transmission system along the first axis, and (2) scan the second mirror with respect to a second axis that is orthogonal to the first axis for targeting the scanning ladar transmission system along the second axis, wherein the combination of the mirror scan positions for the first and second mirrors defines the range points to which the scanning ladar transmission system is targeted, and wherein the beam scanner is further configured to scan at least one of the first and second mirrors as a function of the shot list.

6. The apparatus of claim 3 wherein the processor, as part of the processing operation, is further configured to:

determine, based on a parameter indicative of an amount of time needed by the scanning ladar transmission system between successive ladar pulses, whether any line repeats are to be used for the scanning ladar transmission system to target the range points;

sort the range points into the ordered set based on the line repeat determinations and the interline detour determinations; and

in response to a determination that a line repeat is to be used, tag the shot list with a line repeat identifier within the ordered set at a location where the line repeat is to be performed; and

wherein the beam scanner is further configured to scan the mirror to a plurality of mirror scan positions in accordance with the shot list including any interline detour identifiers and any line repeat identifiers present therein to target the range points via the dynamic scan pattern.

7. The apparatus of claim 6 wherein the processor, as part of the processing operation, is further configured to:

for each of a plurality of pairs of range points, (1) compute a data value as a function of the row and column identifiers associated with the range points of the pair such that the computed data value is indicative of an amount of time needed by the scanning ladar transmission system to scan from a first range point of the pair to a second range point of the pair, (2) perform the line repeat determinations based on the computed data values as compared to the parameter indicative of the amount of time needed by the scanning ladar transmission system between successive ladar pulses, and (3) perform the interline detour determinations based on the computed data values as compared to the parameter indicative of the amount of time needed by the scanning ladar transmission system to (i) scan from a current row to another row, (ii) scan to a range point in the another row, and (iii) return to the current row.

8. The apparatus of claim 7 wherein the mirror comprises a first mirror and a second mirror, wherein the beam scanner is further configured to (1) scan the first mirror with respect to a first axis for targeting the scanning ladar transmission system along the first axis, and (2) scan the second mirror with respect to a second axis that is orthogonal to the first axis for targeting the scanning ladar transmission system along the second axis, wherein the combination of the mirror scan positions for the first and second mirrors defines the range points to which the scanning ladar transmission system is targeted;

and

wherein the beam scanner is further configured to scan at least one of the first and second mirrors as a function of the shot list.

9. The apparatus of claim 3 wherein the scanning ladar transmission system further comprises a beam scanner controller, wherein the processor is part of the beam scanner controller, and wherein the beam scanner controller is further configured to (1) generate a control signal as a function of the shot list, and (2) provide the control signal the beam scanner;

and

wherein the beam scanner is configured to scan the mirror in response to the control signal.

10. The apparatus of claim 9 wherein the mirror comprises a first mirror and a second mirror, wherein the beam scanner is further configured to (1) in response to a first control signal from the beam scanner controller, scan the first mirror with respect to a first axis for targeting the scanning ladar transmission system along the first axis, and (2) in response to a second control signal from the beam scanner controller, scan the second mirror with respect to a second axis that is orthogonal to the first axis for targeting the scanning ladar transmission system along the second axis, wherein the combination of the mirror scan positions for the first and second mirrors defines the range points to which the scanning ladar transmission system is targeted;

and

wherein the beam scanner controller is further configured (1) generate the first control signal as a function of the shot list, (2) generate the second control signal, and (3) provide the first and second control signals to the beam scanner.

11. The apparatus of claim 10 wherein the beam scanner controller is further configured to generate the second control signal as a function of the shot list.

12. The apparatus of claim 3 wherein the scanning ladar transmission system further comprises:

a beam scanner controller, the beam scanner controller in communication with the processor and the beam scanner, wherein the beam scanner controller is configured to (1) receive the shot list from the processor, (2) generate a control signal as a function of the received shot list, and (3) provide the control signal the beam scanner; and

wherein the beam scanner is configured to scan the mirror in response to the control signal.

13. The apparatus of claim 12 wherein the mirror comprises a first mirror and a second mirror, wherein the beam scanner is further configured to (1) in response to a first control signal from the beam scanner controller, scan the first mirror with respect to a first axis for targeting the scanning ladar transmission system along the first axis, and (2) in response to a second control signal from the beam scanner controller, scan the second mirror with respect to a second axis that is orthogonal to the first axis for targeting the scanning ladar transmission system along the second axis, wherein the combination of the mirror scan positions for the first and second mirrors defines the range points to which the scanning ladar transmission system is targeted;

and

wherein the beam scanner controller is further configured (1) generate the first control signal as a function of the shot list, (2) generate the second control signal, and (3) provide the first and second control signals to the beam scanner.

14. The apparatus of claim 13 wherein the beam scanner controller is further configured to generate the second control signal as a function of the shot list.

15. The apparatus of claim 3 wherein the scanning ladar transmission system further comprises:

a light source, wherein the light source is configured to generate a plurality of ladar pulses in response to a plurality of firing commands that are coordinated with the shot list, and wherein the light source is positioned to direct its ladar pulses onto the scanning mirror.

16. The apparatus of claim 3 wherein the processor is further configured to (1) apply a range point down selection algorithm to data representative of a field of view for the scanning ladar transmission system, and (2) select a subset of range points within the field of view for targeting by the scanning ladar transmission system based on the applied range point down selection algorithm, wherein the selected subset of range points serve as range points in the shot list.

17. A method comprising:

translating by a processor a range point list for ladar scanner targeting into a shot list for ladar scanner targeting in a manner whereby the shot list supports a dynamic scan pattern which includes interline detouring, wherein the range point list comprises a plurality of range points, and wherein the shot list comprises a plurality of ordered range points from the range point list, wherein the range points have coordinates defined by a first axis and a second axis, wherein the range point list includes a first range point and a second range point in a first row along the first axis and a third range point in a second row along the first axis, wherein the third range point is located between the first and second range points with reference to the second axis;

wherein the translating step further comprises the processor re-ordering range points from the range point list based on a parameter indicative of a detour time needed by the ladar scanner to accommodate an interline detour; and

wherein the re-ordering step comprises the processor sorting the third range point to fall between the first and second range points on the shot list based on the detour time parameter as compared to an amount of time needed by the ladar scanner to detour from the first range point to the third range point and back to the second range point.

18. The method of claim 17 further comprising:

scanning a plurality of mirrors to a plurality of mirror scan positions, wherein the mirror scan positions define where the ladar scanner is targeted; and

as the mirrors are scanning, transmitting a plurality of ladar pulses toward the ordered range points based on the shot list.

19. The method of claim 17 further comprising:

the processor applying a range point down selection algorithm to data representative of a field of view for the ladar scanner; and

the processor selecting a subset of range points within the field of view for targeting by the ladar scanner based on the applied range point down selection algorithm, wherein the selected subset of range points serve as range points in the shot list.