Standoff iris recognition system
An iris recognition system having pupil and iris border conditioning prior to iris mapping and analysis. The system may obtain and filter an image of an eye. A pupil of the mage may be selected and segmented. Portions of the pupil border can be evaluated and pruned. A curve may be fitted on at least the invalid portions of the pupil border. The iris of the eye with an acceptable border of the pupil as an inside border of the iris may be selected from the image. The iris outside border having sclera and eyelash/lid boundaries may be grouped using a cluster angular range based on eye symmetry. The sclera boundaries may be fitted with a curve. The eyelash/lid boundaries may be extracted or masked. The iris may be segmented, mapped and analyzed.
1. A non-transitory computer readable medium containing instructions that, when executed by a computer, provides an iris recognition system comprising:
an eyefinder;
a filter connected to the eyefinder;
a range module connected to the filter for setting a cluster angular range;
a segmenter connected to the range determiner, wherein the segmenter is a one dimensional polar plus segmentation module and comprises:
a first one dimensional polar segmenter, for sclera borders, connected to the range module;
a second one dimensional polar segmenter, for eyelash/lid borders, connected to the range module;
a first get max peak module connected to the first one dimensional polar segmenter;
a second get max peak module connected to the second one dimensional polar segmenter;
a first one dimensional median filter connected to the first get max peak module and to the border module; and
a second one dimensional median filter connected to the second get max peak module and to the border module;
a border module connected to the segmenter;
a count module connected to the border module; and
a curve fitter connected to the count module.
2. The non-transitory computer readable medium of claim 1 , wherein:
the eyefinder is for providing a valid eye image having a processed pupil border; and
the filter is for smoothing out edges in the eye image.
3. The non-transitory computer readable medium of claim 1 , further containing instructions such that the iris recognition system further comprises a kernel module, for selecting an image of an iris in the eye image, connected to the filter.
4. The non-transitory computer readable medium of claim 1 , further containing instructions such that the iris recognition system further comprises a map analysis module connected to the count module, the curve fitter and the segmenter.
5. A non-transitory computer readable medium containing instructions that, when executed by a computer, provides an iris recognition system comprising:
an eyefinder for providing a valid eye image having a processed pupil border;
a filter connected to the eyefinder for smoothing out edges in the eye image;
a range module connected to the filter;
a segmenter connected to the range determiner;
a border module connected to the segmenter, the border module comprising a sclera border module and an eyelash/lid border module;
a count module connected to the border module, wherein the count module is for determining a number of discontinuities in sclera borders, and further wherein the count module is for determining a number of discontinuities in the eyelash/lid borders; and
a curve fitter connected to the count module;
wherein:
if the number of discontinuities in the sclera borders is less than a first threshold, then the curve fitter is activated for curve fitting the sclera borders; and
if the number of discontinuities in the sclera borders is not less than the first threshold, then the eye image is invalid.
6. The non-transitory computer readable medium of claim 5 , further containing instructions such that the iris recognition system further comprises a kernel module, for selecting an image of an iris in the eye image, connected to the filter.
7. The non-transitory computer readable medium of claim 5 , further containing instructions such that the iris recognition system further comprises a map analysis module connected to the count module, the curve fitter and the segmenter.
8. The non-transitory computer readable medium of claim 5 , wherein:
the range module is for setting a cluster angular range; and
the segmenter is a one dimensional polar plus segmentation module.
9. The non-transitory computer readable medium of claim 5 , wherein:
if the number of discontinuities in the eyelash/lid borders is greater than a second threshold, then the eyelash/lid borders are masked; and
if the number of discontinuities in the eyelash/lid borders is not greater than the second threshold, then the eyelash/lid borders are extracted.
10. A method for iris recognition comprising providing an image of an eye to a processor, the processor being configured to perform the steps of:
selecting a pupil in the image;
segmenting the pupil;
determining a validity of portions of a border of the pupil;
fitting a curve on at least invalid portions of the border of the pupil to form a resulting border of the pupil;
selecting an iris with the pupil having the resulting border from the image of the eye;
clustering iris sclera boundaries and the eyelash/lid boundaries of the iris into first and second groups of boundaries, respectively; and
determining a first number of discontinuities of the first group of boundaries; wherein:
if the first number is less than a first threshold, then the first group of boundaries is fitted with a curve fitting model; and
if the first number is not less than the first threshold, then the eye image is invalid.
11. The method of claim 10 , wherein the processor is further configured to perform the step of:
determining a second number of discontinuities of the second group of boundaries; and
further wherein:
if the second number is not greater than a second threshold, then the second group of boundaries is extracted;
if the second number is not greater than the second threshold and an area between outer borders of the second group of boundaries and an inner border of the iris is less than a third threshold, then the second group of boundaries are weighted accordingly; and
if the second number is greater than the second threshold, then the second group of boundaries is masked; and
further comprising mapping the iris.
12. The method of claim 10 , wherein the processor is further configured to perform the step of constructing an iris map based upon actual inner and outer edge estimates with respect to fitting models.
13. The method of claim 12 , wherein the processor is further configured such that pixels of the iris map are extracted based upon an interpolation of image pixels within inner fitting model and outer fitting model edges at nearly all angles, deemed to be valid, with respect to a pupil center.
14. The method of claim 12 , wherein the processor is further configured such that nearly any pixel that lies within an outer border of the iris and a fitting model shape may be masked.
15. The method of claim 12 , wherein the processor is further configured such that nearly any pixel that lies outside an outer fitting model shape may be discarded.