System and method for structured light illumination with frame subwindows

• US 10,018,464 B2
• Filed: 05/06/2009
• Issued: 07/10/2018
• Est. Priority Date: 05/06/2008
• Status: Active Grant

• Current Assignee: Flashscan3D, LLC
• Original Assignee: Flashscan3D, LLC
• Inventors: Boles, Colby D., Daley, Raymond Charles
• Primary Examiner(s): MESSMORE, JONATHAN R
• Application Number:
  US12/991,405
• Publication Number:
  US 20110058023A1
• Time in Patent Office: 3,352 Days
• Field of Search: 348 64, 348 79- 80, 348202, 3482071, 348262-265, 348335-369
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light

Abstract

A structured light imaging (SLI) system includes a projection system, image sensor system and processing module. The projection system is operable to project a single SLI pattern into an imaging area. The image sensor system is operable to capture images of a 3D object moving through the imaging area. The image sensor system outputs a subset of camera pixels corresponding to a subwindow of a camera frame to generate subwindow images. The processing module is operable to create a 3D surface map of the 3D object based on the subwindow images.

Claims

1. A structured light imaging (SLI) system, comprising:

a projection system that is operable to project a single SLI pattern into an imaging area;

an image sensor system that is operable to capture at least one image of a 3D object moving through the imaging area in a frame period, wherein the image sensor system outputs a subset of camera pixels in the frame period to generate a subwindow image; and

a processing module that is operable to create a 3D surface map of the 3D object using the subwindow image.

2. The SLI system of claim 1, wherein the subwindow image is generated by a subset of camera pixels corresponding to a subwindow of a camera frame.

3. The SLI system of claim 2, wherein dimensions of the subwindow are determined based on at least one of the following factors:

frame rate, image resolution, 3D object size, 3D object velocity, SLI pattern cycle size, and aspect ratio.

4. The SLI system of claim 2, wherein dimensions of the subwindow are determined such that the image sensor system has a frame rate sufficient to reduce motion blur errors due to the movement of the 3D object and capture a sufficient number of images of each object point on the 3D object to generate a PMP 3D phase map.

5. The SLI system of claim 1, wherein the processing module is operable to create a 3D surface map of the 3D object using the subwindow image by determining a motion vector of the 3D object between subsequent subwindow images and determining locations of object points in subsequent subwindow images.

6. The SLI system of claim 5, wherein the processing module is further operable to create a 3D surface map of the 3D object based on determining phase intervals of the SLI pattern projected on object points in subsequent subwindow images.

7. An SLI system for imaging a fingerprint, comprising:

a projection system that is operable to project a single SLI pattern onto a fingerprint in an imaging area;

an image sensor system that is operable to capture a series of images of the fingerprint moving through the imaging area, wherein the image sensor system generates subwindow images of the fingerprint by outputting a subset of camera pixels in a frame period; and

a processing module that is operable to create a 3D surface map of the fingerprint based on the subwindow images.

8. The SLI system of claim 7, wherein each subwindow image has rectangular dimensions, wherein width of the subwindow image corresponds to a finger width and the height is a fraction of an inch.

9. The SLI system of claim 8, wherein the projection system includes:

an array of light emitting diodes (LEDs) operable to emit pulses of light; and

an optical lens system to focus the pulses of light through the SLI pattern along a single axis corresponding to the width of the subwindow image.

10. The SLI system of claim 9, wherein the subwindow image includes a plurality of overlapping subwindow portions and wherein the image sensor system includes:

a plurality of image sensors, wherein each image sensor generates an overlapping subwindow portion.

11. The SLI system of claim 7, further comprising:

an enclosure forming an enclosure aperture, wherein the imaging area includes a portion of the enclosure aperture.

12. The SLI system of claim 7, wherein the processing module is operable to create a 3D surface map of the fingertip based on the subwindow images by determining a motion vector of the fingertip between subsequent subwindow images and determining locations of object points in subsequent subwindow images.

13. The SLI system of claim 12, wherein the processing module is further operable to create a 3D surface map of the fingertip based on determining phase intervals of the SLI pattern projected on object points in subsequent subwindow images.

14. The SLI system of claim 13, wherein the processing module is further operable to process the 3D surface map of the fingertip to create data for a two dimension (2D) rolled equivalent fingerprint.

15. The SLI system of claim 11, further comprising:

a guide for assisting movement of finger through the imaging area.

16. The SLI system of claim 12, wherein determining the motion vector of the fingertip between subsequent subwindow images includes:

generating a cross-correlation of a subset of pixels between adjacent subwindow images.