Automatic Iris Segmentation Using Active Near Infra Red Lighting Carlos Morimoto Thiago Santos Adriano Saturno Laboratory of Technologies for Interaction (LaTIn) Institute of Mathematics and Statistics (IME) University of S˜ ao Paulo (USP) hitoshi,thsant,saturno@ime.usp.br SIBGRAPI 2005, Natal - RN - Brazil www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 1 / 22
Teaser We present here a technique for iris segmentation that uses infra-red light in the image acquisition step. The pupil is identified and regions of iris occluded by eyelids are removed. The system can work in low cost adapted hardware. www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 2 / 22
Outline Introduction 1 Acquisition with NIR light 2 Segmentation: pupil, iris and eyelids 3 Implementation and results 4 Conclusion 5 www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 3 / 22
Introduction Iris as an identification method Unique pattern per person Twins don’t present the same pattern Phenotypical feature Two identical irises: 1 chance in 10 78 www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 4 / 22
Introduction Iris as an identification method Unique pattern per person Twins don’t present the same pattern Phenotypical feature Two identical irises: 1 chance in 10 78 Stable along life Structure: 3 rd ¯ to 8 th ¯ month of gestation Pigment changes: until the 1 st ¯ year of life www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 4 / 22
Introduction Iris as an identification method Unique pattern per person Twins don’t present the same pattern Phenotypical feature Two identical irises: 1 chance in 10 78 Stable along life Structure: 3 rd ¯ to 8 th ¯ month of gestation Pigment changes: until the 1 st ¯ year of life Iris Recognition Technology (IRT) Pilot ATMs in USA and England Authentication in European airports Commercial systems available: Evermedia LG Panasonic... www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 4 / 22
Introduction Iris as an identification method Unique pattern per person Twins don’t present the same pattern Phenotypical feature Two identical irises: 1 chance in 10 78 Stable along life Structure: 3 rd ¯ to 8 th ¯ month of gestation Pigment changes: until the 1 st ¯ year of life Iris Recognition Technology (IRT) Pilot ATMs in USA and England Authentication in European airports Commercial systems available: Evermedia LG Panasonic... IRT considered mature for biometry www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 4 / 22
Introduction Problems with IRT adoption Training to use the system positioning calibration www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 5 / 22
Introduction Problems with IRT adoption Training to use the system positioning calibration Difficult to accomplish using low-cost equipment: fixed focus micro cameras web-cams www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 5 / 22
Introduction Problems with IRT adoption Training to use the system positioning calibration Difficult to accomplish using low-cost equipment: fixed focus micro cameras web-cams Acquisition problems: eyelids occlusion specular reflection images out of focus www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 5 / 22
Introduction Problems with IRT adoption Training to use the system positioning calibration Difficult to accomplish using low-cost equipment: fixed focus micro cameras web-cams Acquisition problems: eyelids occlusion specular reflection images out of focus Need a robust, efficient, easy to use and low-cost system for iris segmentation. www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 5 / 22
Introduction Simple model for iris We would like to segment iris identifying the pupil as a circle, the iris as a circle or its outer border - the limbus - and the eyelids as elliptical segments. www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 6 / 22
Introduction Simple model for iris We would like to segment iris identifying the pupil as a circle, the iris as a circle or its outer border - the limbus - and the eyelids as elliptical segments. The eyelids position is arbitrary www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 6 / 22
Acquisition Camera NIR light sources position L 1 and L 2 turned on alternately www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 7 / 22
Acquisition Camera NIR light sources position L 1 and L 2 turned on alternately L 1 → “red eye” effect: bright pupil www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 7 / 22
Acquisition System’s geometry Near Infra Red light (NIR): 700-900nm. Practically invisible to human eye www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 8 / 22
Acquisition System’s geometry Near Infra Red light (NIR): 700-900nm. Practically invisible to human eye Light source L near to projection center C : www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 8 / 22
Acquisition System’s geometry Near Infra Red light (NIR): 700-900nm. Practically invisible to human eye Light source L near to projection center C : C , L and the reflection R ( glint ) are approximately collinears. www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 8 / 22
Acquisition System’s geometry Near Infra Red light (NIR): 700-900nm. Practically invisible to human eye Light source L near to projection center C : C , L and the reflection R ( glint ) are approximately collinears. R near the pupil center P if user is looking to the camera. www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 8 / 22
Segmentation System processing flow www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 9 / 22
Segmentation Pupil Outline Introduction 1 Acquisition with NIR light 2 Segmentation: pupil, iris and eyelids 3 Pupil segmentation Limbus and eyelids segmentation Implementation and results 4 Conclusion 5 www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 10 / 22
Segmentation Pupil Pupil segmentation L 1 produces a bright pupil image Small brightness changes out pupil www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 11 / 22
Segmentation Pupil Pupil segmentation L 1 produces a bright pupil image Small brightness changes out pupil L 2 produces an image with a dark pupil www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 11 / 22
Segmentation Pupil Pupil segmentation L 1 produces a bright pupil image Small brightness changes out pupil L 2 produces an image with a dark pupil Images subtraction gets pupil’s pixels www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 11 / 22
Segmentation Pupil Pupil segmentation L 1 produces a bright pupil image Small brightness changes out pupil L 2 produces an image with a dark pupil Images subtraction gets pupil’s pixels Circle fitting is used to segment the pupil www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 11 / 22
Segmentation Pupil Pupil segmentation L 1 produces a bright pupil image Small brightness changes out pupil L 2 produces an image with a dark pupil Images subtraction gets pupil’s pixels Circle fitting is used to segment the pupil User looking to the camera → glint is over the pupil www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 11 / 22
Segmentation Pupil Pupil segmentation www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 11 / 22
Segmentation Limbus and eyelid Outline Introduction 1 Acquisition with NIR light 2 Segmentation: pupil, iris and eyelids 3 Pupil segmentation Limbus and eyelids segmentation Implementation and results 4 Conclusion 5 www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 12 / 22
Segmentation Limbus and eyelid Limbus segmentation Limbus orientation Sclera is brighter than iris Gradient taken at limbus points to sclera www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 13 / 22
Segmentation Limbus and eyelid Limbus segmentation Limbus orientation Sclera is brighter than iris Gradient taken at limbus points to sclera Sobel operator used to get vertical edges − 1 0 1 − 2 0 2 − 1 0 1 www.ime.usp.br/ ∼ thsant/sibgrapi05 (IME) Iris Segmentation using NIR SIBGRAPI’05 13 / 22
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