April 14, 2004 1

Infrared Identification

Instructor: Natalia Schmid

BIOM 426: Biometrics Systems

April 14, 2004 2

Outline

• Introduction

• Comparison IRID to other biometrics • Principles of IRID • Processing Approaches • IRID Systems • References

April 14, 2004 3

Introduction• Thermography = is an imaging method using cameras sensitive in the infrared spectrum.

• Surveillance applications: visible and infrared images, gait (passive imaging + distance)

• Thermograms drawbacks: - effected by ambient temperature, - by ingestion of certain chemicals/ medications, - physiological conditions as inflammation, arterial blockages etc.

• Radiometric IR camera can be used to produce EKG

April 14, 2004 4

Introduction

What is used for IRID? - Anatomical information: structure of blood vessels

Infrared Cameras: - passive, collecting energy; - Long (8-12 micron) band and Mid (3-5 micron) band image vessels 4 cm below the surface

Two major drawbacks: 1. Camera cost; 2. No large databases.

April 14, 2004 5

Comparison to Other Biometrics

Uniqueness: There is no proof that any biometric is unique.

Facial Thermography is a robust biometric.

- Thermal patterns are derived from pattern of blood vessels transporting warm blood. - Person’s anatomy does not change (aside from growth, injury, surgical intrusion). - Identical twins have different thermograms. - Thermograms contain more information than fingerprints (minutiae). 16 minutia points has to match for fingerprints.

Forgery: can detect attempted disguise. Image can be blocked but not changed.

April 14, 2004 6

April 14, 2004 7

Comparison to Other Biometrics

Example:

- Temperature distribution over artificial hair is different from normal hair distribution. - Skin surface can be distorted. This does not add minutiae. - Plastic surgery can distort skin, but does not change the major vessels. (Distortions are modeled usin rubber sheet effect). - Thermogram can be distorted but it contains an evidence of this.

- A single frame is used for IRID. Different emissivity materials may change thermogram.

April 14, 2004 8

April 14, 2004 9

Comparison to Other Biometrics

Uncontrolled Environment: - IRID works in complete darkness (contrary to visible imaging).

Changes in Appearance: - high permanence; - weight gain or loss causes rubber sheeting distortions.

Non-intrusiveness: All individuals provide useful images while may not provide good fingerprints etc. Cooperation is not necessary.

Identification of Dark-Skinned Individuals: Visible light datasets do not contain data of dark-skinned individuals.

April 14, 2004 10

April 14, 2004 11

Comparison to Other Biometrics

Scaling Issue: - Underlying features: locations of specific junctions among blood vessels (0.1 inch in diameter). - Minutiae can be extracted from thermal contours (low sensitivity cameras) or from absolute location in imagery (high sensitivity cameras). - 175 minutiae can be extracted from full facial image. - The number of possible configurations exceeds human population.

Throughput: Can provide the fastest throughput: non-contact; done at a distance; does not depend on lighting effects ; can recognize multiple faces simultaneously.

Matching is a limiting factor (1 sec. for verification).

April 14, 2004 12

Comparison to Other BiometricsFalse Negatives:

IRID systems are expected to falsely reject only individuals who have new gross thermal condition (sunburn) or facial surgery.

False Accepts: - Depend on quality of imaging. - Prior matching, cold pixels (background, hair, eyeglasses) are converted to random noise. - Correlation matching of image or its parts.

Correlation of Visual and Infrared Images: - matching methods can use visible data bases; - common features: positions of nose, eyes, hair, head shape- IR lacks color of the skin, hair, and eyes - provides detailed anatomical information - For each IR image system can eliminate all visual images that do not match (95%).