Laser range finding

• US 8,988,663 B2
• Filed: 01/22/2013
• Issued: 03/24/2015
• Est. Priority Date: 01/22/2013
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Sisney, Brent L., Hawk, Bryan K., Francis, Robert P., McIntosh, James A.
• Primary Examiner(s): Alsomiri, Isam
• Assistant Examiner(s): Abraham, Samantha K
• Application Number:
  US13/746,590
• Publication Number:
  US 20140204361A1
• Time in Patent Office: 791 Days
• Field of Search: 356/3.01, 356/4.01, 356/4.07, 356/5.01, 356/5.09, 356/9, 356/625
• US Class Current: 356/5.01
• CPC Class Codes: G01C 3/04 Adaptation of rangefinders for combination with telescopes or binoculars
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders

Abstract

Using a hand-held range finding device to range an object in a field of view is difficult due to user-induced jitter. In particular, user-induced jitter introduces uncertainty as to which object in a field of view is actually ranged. Current approaches attempt to mitigate user-induced jitter by requiring a user to mount the hand-held range finding device onto a stabilizing device (e.g., a tripod). However, such approaches require the user to carry additional equipment. Embodiments of the present disclosure enable the user to visually confirm which object in a field of view is actually ranged during a range finding event by generating a composite image that includes a visual representation of a laser pulse emitted by the range finding device reflecting off an object in the field of view. Advantageously, disclosed embodiments provide true hand-held range finding capabilities without requiring the use of stabilization assistance techniques.

Claims

1. A method for determining a distance to a target object using a laser range finding device, the method comprising:

emitting at least one laser pulse toward the target object;

receiving reflected energy in response to the at least one laser pulse reflecting off a surface, the surface being associated with at least the target object or another object in an area surrounding the target object;

capturing an image that includes the target object and the area surrounding the target object;

mapping a location associated with the at least one laser pulse reflecting off the surface to a coordinate corresponding to a coordinate system of the captured image;

generating a composite image for each captured image, the composite image including a visual representation of the at least one laser pulse overlaid on the captured image using the mapping of the location of the at least one laser pulse;

collecting information corresponding to movement of the laser range finding device between the capture of at least two images, wherein the information is collected via at least one of the following;

motion sensors and image processing;

determining an offset between the coordinate systems of the at least two images using the collected information;

generating an aggregated composite image of the at least two images using the determined offset between the at least two images; and

displaying the aggregated composite image with a selectable marking, for each of the at least two images, a user can select to designate that a source of the reflected energy corresponds to the surface of the target object.

2. The method of claim 1 further comprising displaying the composite image.

3. The method of claim 1 further comprising:

based on information associated with the emission and reflected energy of the at least one laser pulse, calculating a distance between a geographical location of the laser range finding device and a geographical location of the surface; and

displaying the calculated distance on the composite image with the visual representation of the reflection.

4. The method of claim 1 wherein mapping includes:

determining a targeting reticle'"'"'s coordinate with respect to the coordinate system of the captured image at the time of capturing the image, wherein the targeting reticle is used to aim the laser range finding device toward the target object; and

using the targeting reticle'"'"'s coordinate as the coordinate of the location associated with the at least one laser pulse reflecting off the surface.

5. The method of claim 1 further comprising:

wherein the captured image further includes an image of the at least one laser pulse reflecting off the surface; and

determining a coordinate of a location of the at least one laser pulse reflecting off the surface with respect to the coordinate system of the captured image.

6. The method of claim 1 further comprising displaying the composite image with a selectable marking a user can select to designate that a source of the reflected energy corresponds to the surface of the target object.

7. The method of claim 1 further comprising displaying the aggregated composite image.

8. The method of claim 1 further comprising:

isolating a region of interest associated with a first captured image of a sequence of captured images;

comparing the region of interest associated with the first captured image with at least one selected region of the second image to determine a difference between at least one image parameter associated with the region of interest associated with the first image and the at least one selected region of the second image, the at least one selected region of the second image being selected based on an estimated offset between the first captured image and the second captured image, the estimated offset associated with movement of the laser range finding corresponding to movement of the laser range finding device between the capture of the first captured image and the second captured image; and

overlaying one of the at least one selected region of the second image having a least difference between the at least one image parameter on the region of interest associated with the first captured image.

9. A laser range finding device for determining a distance to a target object, the laser range finding device comprising:

a laser emitter configured to emit at least one laser pulse toward the target object;

a laser reflection receiver configured to receive reflected energy in response to the at least one laser pulse reflecting off a surface, the surface being associated with at least the target object or another object in an area surrounding the target object;

a camera configured to capture an image that includes the target object and the area surrounding the target object;

a mapping processor configured to map a location associated with the at least one laser pulse reflecting off the surface to a coordinate corresponding to a coordinate system of the captured image;

an image processor configured to generate a composite image for each captured image, the composite image including a visual representation of the at least one laser pulse overlaid on the captured image using the mapping of the location of the at least one laser pulse;

a sensor configured to collect information corresponding to movement of the laser range finding device between the capture of at least two images;

a jitter processor configured to determine an offset between the coordinate systems of the at least two images using the collected information;

wherein the image processor is further configured to generate an aggregated composite image of the at least two images using the determined offset between the at least two images; and

a display configured to display the aggregated composite image with a selectable marking, for each of the at least two images, a user can select to designate that a source of the reflected energy corresponds to the surface of the target object.

10. The laser range finding device of claim 9 further comprising a display configured to display the composite image.

11. The laser range finding device of claim 9 further comprising:

a distance ranging calculator configured to, based on information associated with the emission and reflected energy of the at least one laser pulse, calculate a distance between a geographical location of the laser range finding device and a geographical location of the surface; and

a display configured to display the calculated distance on the composite image with the visual representation of the reflection.

12. The laser range finding device of claim 9 wherein the mapping processor is further configured to:

determine a targeting reticle'"'"'s coordinate with respect to the coordinate system of the captured image at the time of capturing the image, wherein the targeting reticle is used to aim the laser range finding device toward the target object; and

use the targeting reticle'"'"'s coordinate as the coordinate of the location associated with the at least one laser pulse reflecting off the surface.

13. The laser range finding device of claim 9 wherein the camera is further configured to detect and capture a representation of the at least one laser pulse reflecting off the surface and wherein the mapping processor is further configured to determine a coordinate of a location of the representation with respect to the coordinate system of the captured image.

14. The laser range finding device of claim 9 wherein the display is further configured to display a selectable marking a user can select to designate that a source of the reflected energy corresponds to the surface of the target object.

15. The laser range finding device of claim 9 further comprising a display for displaying the aggregated composite image.

16. The laser range finding device of claim 9 wherein the mapping processor further includes:

an isolation module configured to isolating a region of interest associated with a first captured image of a sequence of captured images;

a comparison module configured to comparing the region of interest associated with the first captured image with at least one selected region of the second image to determine a difference between at least one image parameter associated with the region of interest associated with the first image and the at least one selected region of the second image, the at least one selected region of the second image being selected based on an estimated offset between the first captured image and the second captured image, the estimated offset associated with movement of the laser range finding corresponding to movement of the laser range finding device between the capture of the first captured image and the second captured image; and

wherein the image processor is further configured to overlay one of the at least one selected region of the second image having a least difference between the at least one image parameter on the region of interest associated with the first captured image.

17. A non-transitory computer readable medium having computer readable program codes embodied thereon for determining a distance to a target object, the computer readable program codes including instructions that, when executed by a processor, cause the processor to:

map a location associated with at least one laser pulse reflecting off a surface to a coordinate corresponding to a coordinate system of a captured image, wherein the surface is associated with at least the target object or another object in an area surrounding the target object and wherein the captured image includes at least the target object and the area surrounding the target object;

generate a composite image for each captured image, the composite image including a visual representation of the at least one laser pulse overlaid on the captured image using the mapping of the location of the at least one laser pulse reflecting off the surface;

collect information corresponding to movement of the laser range finding device between the capture of at least two images, wherein the information is collected via at least one of the following;

motion sensors and image processing;

determine an offset between the coordinate systems of the at least two images using the collected information;

generate an aggregated composite image of the at least two images using the determined offset between the at least two images; and

display the aggregated composite image with a selectable marking, for each of the at least two images, a user can select to designate that a source of the reflected energy corresponds to the surface of the target object.