System and method for configuring an imaging tool

• US 20040247203A1
• Filed: 06/09/2003
• Published: 12/09/2004
• Est. Priority Date: 06/09/2003
• Status: Active Grant

• Current Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.), Eaton Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: DellʼEva, Mark L.
• Granted Patent: US 7,181,083 B2
• Time in Patent Office: Days
• US Class Current: 382/294
• CPC Class Codes: G02B 27/62 Optical apparatus specially adapted for adjusting optical elements during the assembly of optical systems
• CPC Class Codes: G02B 7/003 Alignment of optical elements G02B7/001, G02B7/002 take precedence; for mirrors G02B7/1822

Abstract

An imaging tool, including a lens, an imager, and a housing component, can be configured using a focus subsystem and an alignment subsystem. The focus subsystem can perform a focus heuristic using a source image to determine the appropriate focus of the lens. The alignment subsystem can perform an alignment heuristic using a calibration image to calculate the appropriate roll angle for the imager. The system can adjust the focus and alignment of the imaging tool in an automated manner. In some embodiments, the lens and alignment can be moved while they are within the housing component. System calculations can be performed accurately at the sub-pixel level. The system can be configured so that all computations are performed within the imaging tool itself, with the imaging tool passing messages to the configuration system regarding configuration instructions.

Claims

1. A method for configuring an imaging tool by aligning an imager within a housing component, comprising:

capturing a calibration image from a source image with the imaging tool;

calculating an adjustment by comparing a calibration reference point to a corresponding reference point in a template image;

moving an alignment mechanism without human intervention in accordance with the calculated adjustment; and

aligning an imager within a housing component through the movement of the alignment mechanism.

2. The method of claim 1, wherein a device inside the imaging tool calculates the adjustment.

3. The method of claim 2, wherein a controller receives a message from the imaging tool that includes the calculated adjustment and wherein the controller uses the message from imaging tool to invoke the movement in the alignment mechanism.

4. The method of claim 1, wherein the adjustment includes an offset and a roll angle.

5. The method of claim 1, wherein the source image includes at least two circles, wherein the calibration image includes at least two circles, and wherein the template image is the source image.

6. The method of claim 1, wherein the calibration reference point is a centroid of an object in the calibration image, and wherein the corresponding reference point in the template image is the centroid of the corresponding object in the template image.

7. The method of claim 1, wherein a tab connected to a circuit board connected to the imager is moved by the alignment mechanism to align the imager within the housing component.

8. The method of claim 1, wherein the imaging tool includes a housing component, a lens, and a circuit board;

and

wherein the housing component, lens, and circuit board are not permanently connected until after the alignment mechanism automatically moves in accordance with the calculated adjustment.

9. The method of claim 1, wherein the adjustment is calculated to sub-pixel accuracy.

10. The method of claim 9, wherein a pixel is no larger than 12 square microns.

11. The method of claim 1, further comprising installing the imaging tool in a vehicle for use in an airbag deployment application.

12. The method of claim 11, wherein the imaging tool is configured in accordance with an at-risk-zone of the vehicle.

13. The method of claim 1, further comprising focusing the imaging tool using a first picture of the source image, wherein the first picture is taken at a preset focus point.

14. The method of claim 13, wherein focusing the imaging tool includes taking three pictures of the source image, wherein a second picture is taken on a first side of the preset focus point, and wherein a third picture is taken on a second side of the preset focus point.

15. The method of claim 13, further comprising determining a focus adjustment using one of a blur circle diameter heuristic and an edge contrast heuristic.

16. The method of claim 1, further comprising locking a lens permanently in place using a mechanical fastener after aligning the imager within the housing unit.

17. The method of claim 16, wherein the mechanical fastener is one of a quick-set UV and a thermal cure epoxy.

18. The method of claim 1, attaching a circuit board permanently to a housing using component using one of a tapered fastener and a compliant press-fit fastener.

19. The method of claim 1, wherein moving an alignment mechanism in accordance with the adjustment is accomplished in a single angular motion.

20. The method of claim 1, further comprising positioning an alignment station between approximately 15 and 25 inches away from the lens.

21. The method of claim 1, wherein two imaging tools are configured in substantially simultaneous manner with respect to a single source image.

22. A method of configuring an image sensor for use in a vehicle, comprising:

loading a lens, an imager, and an housing component into an alignment station;

connecting an imager to a control device, wherein the imager is located on a circuit board;

focusing the lens automatically with a lens focusing mechanism; and

aligning the circuit board automatically with an alignment mechanism, wherein the imager is focused and aligned for use in a vehicle.

23. The method of claim 22, wherein the lens is not yet focused when loaded into said alignment station.

24. The method of claim 22, wherein the lens, the circuit board, and the housing component are not securely fastened together when loaded into the alignment station.

25. The method of claim 22, wherein the alignment station is pre-aligned to a source test image mounted between approximately 17 and 22 inches away from the lens.

26. The method of claim 22, wherein the focusing of the lens includes the capture of at least three images, with at least one image captured at a preset focus point, with at least one image captured above a preset focus point, and with at least one image captured below a preset focus point.

27. The method of claim 22, wherein focusing the lens includes at least one of:

deriving a focus correction using a blur circle diameter; and

computing a focus correction using a edge contrast parameter.

28. The method of claim 22, wherein aligning the circuit board automatically with an alignment mechanism, includes:

calculating an offset between an ideal location and a current location; and

moving the board in accordance with the calculated offset.

29. The method of claim 22, said aligning the board automatically with an alignment mechanism, including:

calculating a roll angle between an ideal position and a current position; and

moving the circuit board in accordance with the calculated roll angle.

30. The method of claim 22, wherein the alignment mechanism moves the circuit board with a single angular movement.

31. The method of claim 22, wherein a plurality of imaging tools are focused and aligned in a coordinated fashion in a substantially simultaneous manner using the source image and the same alignment station.

32. The method of claim 22, said aligning the circuit board automatically with an alignment mechanism, comprising:

sending a message from a device on the circuit board to a controller;

instructing the alignment mechanism in accordance with the message;

wherein the controller is not part of the imaging tool;

wherein the message includes an adjustment value calculated by a device on the circuit board; and

wherein the controller instructs the alignment mechanism in accordance with the message.

33. An imaging tool configuration system, comprising:

a first imaging tool, including a first lens, a first imager, and a first housing component;

wherein said first imaging tool provides for the capture of a first calibration image;

a focus subsystem, including a first focus actuator and an automated focus heuristic, wherein said focus subsystem performs said automated focus heuristic, and wherein said first focus actuator automatically focuses said first lens; and

an alignment subsystem, including an automated alignment heuristic and a first alignment actuator, wherein said alignment subsystem performs said automated alignment heuristic, and wherein said alignment actuator automatically aligns said first imager.

34. The system of claim 33, wherein said first imager is mounted on a printed circuit board that is moved by said alignment subsystem in a single angular motion.

35. The system of claim 33, wherein said alignment subsystem includes a computer on said first imager for calculating an adjustment used by said alignment actuator to automatically align said first imager.

36. The system of claim 33, wherein said first calibration image includes at least two circles.

37. The system of claim 33, wherein said automated alignment heuristic aligns a reference data point in said first calibration image within two microns of a corresponding data point in a template image.

38. The system of claim 37, further comprising:

a second imaging tool, including a second lens, a second imager, and a second housing component;

wherein said second imaging tool provides for the capture of a second calibration image;

wherein said focus subsystem further includes a second focus actuator, wherein said focus subsystem performs said automated focus heuristic, and wherein said second focus actuator automatically focuses said second lens in a substantially simultaneous manner with respect to the automatic focusing of said first lens; and

wherein said alignment subsystem further includes a second alignment actuator, and wherein said alignment actuator automatically aligns said second imager in a substantially simultaneous manner with respect to the automatic aligning of said first imager.