Planar light illumination and linear imaging (PLILIM) device with image-based velocity detection and aspect ratio compensation

• US 7,164,810 B2
• Filed: 06/27/2002
• Issued: 01/16/2007
• Est. Priority Date: 11/21/2001
• Status: Expired due to Fees

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Zhu, Xiaoxun, Knowles, Carl Harry, Schnee, Michael D.
• Primary Examiner(s): Dang; Duy M.
• Application Number:
  US10/186,320
• Publication Number:
  US 20030156303A1
• Time in Patent Office: 1,664 Days
• Field of Search: 382312-319, 358473-474, 358/509, 235/462.01
• US Class Current: 382/313
• CPC Class Codes: G06V 10/12 Details of acquisition arrangements; Constructional details thereof
• CPC Class Codes: H04N 1/193 using electrically scanned linear arrays , e.g. linear CCD arrays
• CPC Class Codes: H04N 2201/04703 using the scanning elements as detectors, e.g. by performing a prescan
• CPC Class Codes: H04N 2201/04712 using unbroken arrays of detectors, i.e. detectors mounted on the same substrate
• CPC Class Codes: H04N 2201/04734 Detecting at frequent intervals, e.g. once per line for sub-scan control
• CPC Class Codes: H04N 2201/04743 by detecting the image directly

Abstract

An imaging device comprising a plurality of linear imaging arrays and image formation optics that provide field of views corresponding to the plurality of linear image arrays. At least one illumination module produces planar light illumination that substantially overlaps the field of views corresponding to the plurality of linear imaging arrays. Image processing circuitry performs image-based velocity estimation operations on composite 2-D images derived from sequential image capture operations. Velocity data is derived that represents an estimated velocity of the imaging device with respect to at least one target object disposed in the fields of view. The image processing circuitry also performs image transformation operations (or camera control operations) which are based upon the velocity data, to compensate for aspect ratio distortions in captured images that would otherwise result from variations in velocity of the imaging device with respect to the target object(s).

Claims

1. An imaging device comprising:

a plurality of linear imaging arrays and image formation optics that provide field of views corresponding to the plurality of linear imaging arrays;

at least one illumination module that produces planar light illumination that overlaps the field of views corresponding to the plurality of linear imaging arrays; and

image processing circuitry that analyzes pixel data values of a plurality of composite 2-D images, wherein each composite 2-D image is derived from sequential image capture operations of one corresponding linear imaging array so as to derive velocity data that represents an estimated velocity of said imaging device with respect to at least one target object disposed in said field of views.

2. The imaging device of claim 1, wherein said image processing circuitry produces a first image of portions of said target object(s), said first image having a substantially constant aspect ratio, and utilizing image transformation operations that are based upon the velocity data or camera control operations that are based upon the velocity data.

3. The imaging device of claim 2, further comprising a controller, operably coupled to said at least one illumination module, that controls at least one time period of illumination or at least one power level of illumination such that said first image has a substantially uniform white level.

4. The imaging device of claim 1, wherein said linear imaging arrays are spaced apart along the intended direction of object motion, and line rate of said linear imaging arrays is substantially constant over said sequential image capture operations.

5. The imaging device of claim 1, wherein said planar light illumination overfills said field of views over a range of working distances of the imaging device during said sequential image capture operations.

6. The imaging device of claim 1, wherein said planar light illumination is produced from at least one source of coherent illumination.

7. The imaging device of claim 6, wherein said at least one source comprises at least one visible laser diode.

8. The imaging device of claim 7, wherein said at least one source comprises a plurality of visible laser diodes.

9. The imaging device of claim 1, wherein said planar light illumination is produced from at least one source of incoherent illumination.

10. The imaging device of claim 9, wherein said at least one source comprises at least one light emitting diode.

11. The imaging device of claim 10, wherein said at least one source comprises a plurality of light emitting diodes.

12. The imaging device of claim 1, wherein said planar light illumination is produced by at least one planar light illumination module comprising an illumination source, at least one focusing lens element, and at least one cylindrical lens element integrated into a modular housing.

13. The imaging device of claim 12, wherein said illumination source comprises at least one source of coherent illumination.

14. The imaging device of claim 13, wherein said at least one source of coherent illumination comprises at least one visible laser diode.

15. The imaging device of claim 14, wherein said at least one source of coherent illumination comprises a plurality of visible laser diodes.

16. The imaging device of claim 12, wherein said illumination source comprises at least one source of incoherent illumination.

17. The imaging device of claim 16, wherein said at least one source of incoherent illumination comprises at least one light emitting diode.

18. The imaging device of claim 17, wherein said at least one source of incoherent illumination comprises a plurality of light emitting diodes.

19. The imaging device of claim 12, wherein said planar light illumination is produced by planar light illumination arrays disposed on opposite sides of said plurality of linear imaging arrays, each planar light illumination array comprising at least one planar light illumination module.

20. The imaging device of claim 12, wherein said planar light illumination is produced by multiple planar light illumination modules that are spaced apart and oriented on an optical bench in a manner that produces a composite beam of planar light illumination with substantial uniform intensity distribution over a range of working distances of the imaging device.