Systems and methods for imaging

• US 9,693,038 B2
• Filed: 04/12/2016
• Issued: 06/27/2017
• Est. Priority Date: 04/21/2015
• Status: Active Grant

• Current Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Original Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Inventors: McCloskey, Scott, Miller, Ben
• Primary Examiner(s): BARNES, TED W
• Application Number:
  US15/096,528
• Publication Number:
  US 20160316190A1
• Time in Patent Office: 441 Days
• CPC Class Codes: G06K 7/10811 Focalisation
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B
• CPC Class Codes: G06K 7/10841 Particularities of the light-sensitive elements semiconductor devices H01L
• CPC Class Codes: G06K 7/1413 1D bar codes
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 2207/10052 Images from lightfield camera
• CPC Class Codes: G06T 2207/20212 Image combination
• CPC Class Codes: G06T 2207/20221 Image fusion; Image merging
• CPC Class Codes: G06T 2207/30201 Face
• CPC Class Codes: G06T 2207/30204 Marker
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 7/55 from multiple images
• CPC Class Codes: G06T 7/557 from light fields, e.g. from plenoptic cameras
• CPC Class Codes: G06T 7/593 from stereo images
• CPC Class Codes: G06V 40/166 using acquisition arrangements
• CPC Class Codes: G06V 40/172 Classification, e.g. identification
• CPC Class Codes: G06V 40/19 Sensors therefor
• CPC Class Codes: G06V 40/197 Matching; Classification
• CPC Class Codes: H04N 13/156 Mixing image signals
• CPC Class Codes: H04N 13/229 using lenticular lenses, e.g. arrangements of cylindrical lenses

Abstract

An imaging device has a light field imager and a processor. The light field imager includes a microlens array, and a light field sensor positioned proximate to the microlens array, having a plurality of pixels and recording light field data of an optical target from light passing through the microlens array. The processor is configured to: receive the light field data of the optical target from the light field sensor, estimate signal to noise ratio and depth of the optical target in the light field data, select a subset of sub-aperture images based on the signal to noise ratio and depth, combine the selected subset of sub-aperture images, and perform image analysis on the combined subset of sub-aperture images.

Claims

1. An imaging device, comprising:

a light field imager, comprising;

a microlens array; and

a light field sensor positioned proximate to the microlens array, having a plurality of pixels and recording light field data of an optical target from light passing through the microlens array; and

a processor configured to;

receive the light field data of the optical target from the light field sensor;

estimate signal to noise ratio and depth of the optical target in the light field data;

select a subset of sub-aperture images based on the signal to noise ratio and depth;

combine the selected subset of sub-aperture images; and

perform image analysis on the combined subset of sub-aperture images.

2. The imaging device of claim 1, wherein the light field data comprises a plurality of sub-aperture images.

3. The imaging device of claim 2, wherein estimating the signal to noise ratio is performed using sensor characterization.

4. The imaging device of claim 3, wherein sensor characterization includes sensor noise level, gain, exposure time, or any combination thereof.

5. The imaging device of claim 4, wherein sensor characterization is determined from pixel intensities.

6. The imaging device of claim 1, wherein estimating depth of the optical target from the light field imager is directly determined from the light field data.

7. The imaging device of claim 1, wherein estimating depth of the optical target from the light field imager is through registration of two sub-aperture images.

8. The imaging device of claim 1, comprising a pre-determined table of optimal subsets of sub-aperture images at different signal to noise ratios and depths of a theoretical optical target from the light field imager.

9. The imaging device of claim 8, wherein the subset of sub-aperture images is selected from the pre-determined table.

10. The imaging device of claim 1, wherein combining the subset of sub-aperture images includes a quantized shifting and adding together the subset of sub-aperture images.

11. The imaging device of claim 1, wherein the imaging device is an indicia scanner.

12. The imaging device of claim 1, wherein the image analysis is facial recognition.

13. The imaging device of claim 1, where the image analysis is iris recognition.

14. A method, comprising:

capturing light field data of an optical target with a light field sensor;

estimating signal to noise ratio and depth of the optical target in the light field data;

selecting a subset of sub-aperture images based on the signal to noise ratio and depth;

combining the selected subset of sub-aperture images; and

performing image analysis on the combined subset of sub-aperture images.

15. The method of claim 14, wherein the light field data comprises a plurality of sub-aperture images.

16. The method of claim 15, wherein estimating the signal to noise ratio is performed using sensor characterization of sensor noise level, gain, exposure time, or any combination thereof.

17. The method of claim 14, wherein estimating depth of the optical target from the light field imager is determined directly from the light field data.

18. The method of claim 14, wherein estimating depth of the optical target from the light field imager is through registration of two sub-aperture images.

19. The method of claim 16, wherein the subset of sub-aperture images is selected from a pre-determined table comprising optimal subsets of sub-aperture images at different signal to noise ratios and depths of a theoretical optical target from the light field imager.

20. The method of claim 19, wherein combining the subset of sub-aperture images includes a quantized shifting and adding together the subset of sub-aperture images.