System and method for dynamic windowing

• US 8,243,289 B2
• Filed: 06/09/2010
• Issued: 08/14/2012
• Est. Priority Date: 05/29/2009
• Status: Expired due to Fees

• Current Assignee: Perceptron Incorporated (Atlas Copco AB)
• Original Assignee: Perceptron Incorporated (Atlas Copco AB)
• Inventors: Lin, Chengchih, Manning, Craig A., Keshavmurthy, Shyam P.
• Primary Examiner(s): Nguyen, Sang
• Application Number:
  US12/797,083
• Publication Number:
  US 20100302558A1
• Time in Patent Office: 797 Days
• Field of Search: 356600-624, 250/559.2, 250/548, 382203-206, 382/151, 382/154
• US Class Current: 356/623
• CPC Class Codes: G01B 11/2531 using several gratings, projected with variable angle of incidence on the object, and one detection device
• CPC Class Codes: G01B 11/2545 with one projection direction and several detection directions, e.g. stereo
• CPC Class Codes: G01B 11/2755 using photoelectric detection means
• CPC Class Codes: G01B 2210/286 Projecting a light pattern on the wheel or vehicle body
• CPC Class Codes: G01B 2210/52 Combining or merging partially overlapping images to an overall image
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light

Abstract

A sensor system and method for analyzing a feature in a sensing volume is provided. The system receives image data from a sensor, where the image data including peaks corresponding to the intersection of laser lines with the feature. The system generates a dynamic window based on the entropy of the peaks.

Claims

1. A sensor system for analyzing a feature in a sensing volume, the sensor system comprising:

a mounting structure;

a laser source being attached to the mounting structure and configured to project a plurality of laser lines onto the feature;

a sensor being attached to the mounting structure and configured to image the intersection of the laser lines with the feature;

a controller in communication with the sensor to receive image data;

the image data including peaks corresponding to the intersection of the laser lines with the feature where the controller is configured to generate a dynamic window based on the entropy of the peaks, where the entropy of the peaks is calculated based on a distance between the peaks.

2. The sensor system according to claim 1, wherein the controller separates the image data into a plurality of zones.

3. The sensor system according to claim 2, wherein the sensor has a plurality of pixels organized in rows and columns, wherein the controller sums and normalizes each column of pixels in each zone to generate a profile.

4. The sensor system according to claim 3, wherein the controller identifies peaks in the profile.

5. The sensor system according to claim 4, wherein the controller calculates the center of gravity of each peak.

6. The sensor system according to claim 1, wherein the controller calculates the entropy based on the relationship:

7. The sensor system according to claim 1, wherein the controller utilizes the entropy to generate a target zone corresponding to the intersection of the laser lines with the feature.

8. The sensor system according to claim 7, wherein the controller identifies the position of lines in the target zone and tracks each laser line to find and upper endpoint and a lower endpoints of each laser line.

9. A sensor system for analyzing a feature in a sensing volume, the sensor system comprising:

a mounting structure;

a laser source being attached to the mounting structure and configured to project a plurality of laser lines onto the feature;

a sensor being attached to the mounting structure and configured to image the intersection of the laser lines with the feature;

a controller in communication with the sensor to receive image data;

the image data including peaks corresponding to the intersection of the laser lines with the feature where the controller is configured to generate a dynamic window based on the entropy of the peaks;

wherein the controller calculates a distance between each adjacent peak.

10. The sensor system according to claim 9, wherein the controller calculates a zone entropy based on the distance between each adjacent peak.

11. The sensor system according to claim 10, wherein the controller calculates the zone entropy based on a difference of the distance between each adjacent peak and the average distance between each adjacent peak.

12. The sensor system according to claim 11, wherein the controller calculates the zone entropy based on a sum of squares of the difference of the distance between each adjacent peak and the average distance between each adjacent peak.

13. The sensor system according to claim 12, wherein the sum is normalized based on a total number of peaks in the zone.

14. A sensor system for analyzing a feature in a sensing volume, the sensor system comprising:

a mounting structure;

a laser source being attached to the mounting structure and configured to project a plurality of laser lines onto the feature;

a sensor being attached to the mounting structure and configured to image the intersection of the laser lines with the feature;

a controller in communication with the sensor to receive image data;

the image data including peaks corresponding to the intersection of the laser lines with the feature where the controller is configured to generate a dynamic window based on the entropy of the peaks;

wherein the controller utilizes a tracking window to filter noise when tracking each laser line;

the tracking window adjusting based on a previous position measurement of the laser line.

15. A method for analyzing a feature in a sensing volume, the sensor system comprising:

receiving image data from a sensor, the image data including peaks corresponding to the intersection of laser lines with the feature;

generating a dynamic window based on a distance between the peaks using a controller.

16. The method according to claim 15, wherein the controller separates the image data into a plurality of zones, the sensor having a plurality of pixels organized in rows and columns, wherein the controller sums and normalizes each column of pixels in each zone to generate a profile.

17. The sensor system according to claim 16, wherein the controller identifies peaks in the profile and calculates a distance between each adjacent peak.

18. The sensor system according to claim 17, wherein the controller calculates the zone entropy based on a sum of squares of the difference of the distance between each adjacent peak and the average distance between each adjacent peak.

19. The sensor system according to claim 15, wherein the controller calculates the entropy based on the relationship:

20. The sensor system according to claim 15, wherein the controller utilizes the entropy to generate a target zone corresponding to the intersection of the laser lines with the feature and identifies the position of lines in the target zone, wherein the controller tracks each laser line to find and upper endpoint and a lower endpoints of each laser line, the controller utilizing a tracking window to filter noise when tracking each laser line and adjusting the tracking window based on an previous position measurement of the laser line.