EXPEDIENT ENCODING SYSTEM

• US 20070274571A1
• Filed: 03/02/2007
• Published: 11/29/2007
• Est. Priority Date: 01/26/2005
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Honeywell International Inc.
• Inventors: Hamza, Rida
• Granted Patent: US 8,045,764 B2
• Time in Patent Office: Days
• US Class Current: 382/117
• CPC Class Codes: G06V 40/193 Preprocessing; Feature extraction

Abstract

An encoding system for an iris recognition system. In particular, it presents a robust encoding method of the iris textures to compress the iris pixel information into few bits that constitute the iris barcode to be stored or matched against database templates of same form. The iris encoding system is relied on to extract key bits of information under various conditions of capture, such as illumination, obscuration or eye illuminations variations.

Claims

1. An encoding method comprising:

extracting significant features of an iris pattern;

encoding the features; and

compressing the encoded iris pattern to fewer bits but sufficient to make a match.

2. The method of claim 1, further comprising embedding the extracting and encoding into segmentation.

3. The method of claim 1, further comprising filtering to detect the significant features of the iris pattern.

4. The method of claim 1, wherein the encoding is effected in stages.

5. The method of claim 1, wherein the encoding is effected in stages with single bits.

6. The method of claim 5, wherein the bits are sign quantized with a positive, negative or an unknown value.

7. The method of claim 5, wherein additional bits are added to improve matching of the features of the iris pattern.

8. A method for encoding comprising:

extracting a feature vector from an iris image at each of several angles; and

dot product-ing each feature vector with a periodic filter.

9. The method of claim 8, wherein the filter is constructed with a symmetric waveform.

10. The method of claim 9, wherein the symmetric waveform sums to zero over its period.

11. The method of claim 8, wherein each feature vector may be sign quantized with a one, zero or unknown.

12. The method of claim 8, wherein the feature vector from the iris image at each of several angles is encoded into fewer bits to be used for matching.

13. The method of claim 8, wherein the feature vector from the iris image at each of several angles is encoded in stages into fewer bits to be used for progressive matching.

14. The method of claim 13, wherein the extracting and encoding are integrated with segmentation of the iris image.

15. A method for encoding comprising:

extracting a feature vector from an iris pattern at each of several one-dimensional radial segments; and

filtering the feature vector.

16. The method of claim 15, further comprising dot product the filtering in an axis of the one-dimensional radial segments.

17. The method of claim 15, further comprising dot product the filtering in an axis of the one-dimensional radial segments, using 0, 1, and unknown bit representation.

18. The method of claim 15, wherein the intensities of the feature vectors can be encoded based upon occurrences of peaks and valleys, using 0, 1, and unknown bit representation.

19. The method of claim 15, further comprising dot product-ing a non-uniform waveform in an axis of the one-dimensional radial segments, using 0, 1, and unknown bit representation.

20. The method of claim 15, further comprising convolution of a symmetric waveform in an axis of the one-dimensional radial segments, using 0, 1, and unknown bit representation.