Image processing apparatus

• US 10,303,916 B2
• Filed: 07/26/2016
• Issued: 05/28/2019
• Est. Priority Date: 07/31/2015
• Status: Active Grant

• Current Assignee: FotoNation Limited (Adeia, Inc.)
• Original Assignee: FotoNation Limited (Adeia, Inc.)
• Inventors: Bazrafkan, Shabab
• Primary Examiner(s): Strege, John B
• Application Number:
  US15/220,195
• Publication Number:
  US 20170032170A1
• Time in Patent Office: 1,036 Days
• CPC Class Codes: G06V 10/141 Control of illumination
• CPC Class Codes: G06V 40/1335 Combining adjacent partial images (e.g. slices) to create a composite input or reference pattern; Tracking a sweeping finger movement
• CPC Class Codes: G06V 40/1341 Sensing with light passing through the finger
• CPC Class Codes: G06V 40/14 Vascular patterns

Abstract

An image processing apparatus comprises a set of infra-red (IR) sources surrounding an image capture sensor and a processor operatively coupled to said IR sources and said image capture sensor. The processor being arranged to acquire from the sensor a succession of images, each illuminated with a different combination of the IR sources. The processor is further arranged to combine component images corresponding to the succession of images by selecting a median value for corresponding pixel locations of the component images as a pixel value for the combined image.

Claims

1. An image processing apparatus comprising:

an image capture sensor;

a set of infra-red (IR) sources surrounding the image capture sensor; and

a processor operatively coupled to said IR sources and said image capture sensor and configured to acquire from the sensor a succession of images, each image illuminated with a different combination of the IR sources such that each in a plurality of the images is captured with illumination from a different direction, the processor being further arranged to combine component images corresponding to the succession of images by selecting a median value for corresponding pixel locations of said component images as a pixel value for the combined image, where the processor arranged to perform 3D temporal median filtering in a cascaded fashion to obtain g sets of cascaded images which are passed through a median filter with g intermediate fused images generated and combined into said combined image.

2. An image processing apparatus as claimed in claim 1 wherein said processor is arranged to acquire each of said succession of images with a high-pass filter to compensate for an illumination gradient across said succession of images from respective illuminating light sources.

3. An image processing apparatus as claimed in claim 2 wherein said processor is further arranged to normalise said images processed with said high-pass filter so that pixel values of said component images are in the range [0,1].

4. An image processing apparatus as claimed in claim 1 wherein said processor is further arranged to apply a Gabor filter bank to said combined image to provide a finger vein map.

5. An image processing apparatus as claimed in claim 1 wherein said processor comprises a processor for a consumer electronic device.

6. An image processing apparatus as claimed in claim 1 wherein said processor comprises at least one dedicated processing module within a consumer electronic device.

7. An image processing apparatus as claimed in claim 1 wherein said apparatus comprises 12>

N>

6 light sources.

8. The image processing apparatus of claim 7 wherein said processor is configured to capture a succession of N images, each lit by one or more different light sources.

9. An image processing apparatus as claimed in claim 1 wherein said processor is further arranged to spatially align said succession of images.

10. An image processing apparatus as claimed in claim 1 wherein each light source comprises an NIR LED.

11. An image processing apparatus as claimed in claim 1 further comprising an image store for at least temporarily storing said succession of images and/or said combined image.

12. An image processing apparatus as claimed in claim 1 wherein the processor is further arranged to combine respective sets of component images corresponding to plural sets of acquired images by selecting a median value for corresponding pixel locations of said component images as a pixel value for a respective intermediate combined image, the processor being arranged to combine said intermediate combined images by selecting a median value for corresponding pixel locations of said intermediate combined images as a pixel value for a final combined image.

13. A consumer electronic device incorporating the image processing apparatus according to claim 1 and being arranged to employ said image processing apparatus to register a user with an application and/or said device and to authenticate a user to an application and/or said device.

14. The image processing apparatus of claim 4 where said processor is further arranged to apply the Gabor filter bank to a fused finger vein image for I different directions, applying the 3D temporal median filter to I different images, and repeating the foregoing steps for p different frequencies.

15. The image processing apparatus of claim 14 where I=24.

16. The image processing apparatus of claim 14 where p=5.

17. The image processing apparatus of claim 16 where the different frequencies are 0.0250 Hz, 0.0270 Hz, 0.0290 Hz, 0.0310 Hz and 0.0330 Hz.