Person Identification by Dental Images using Striae Patterns
Uploaded by k.lakshme on Apr 16, 2007
1. Introduction:T
he Identification of people using their dental records, mainly as radiograph images searches the database of Postmortem (PM) and antemortem (AM) radiographs to determine the identity of the person associated with the PM image. We use a semi-automatic method to extract shapes of the teeth from the AM and PM radiographs, and find the affine transform that best fits the shapes in the PM image to those in the AM images. A ranking of matching scores is generated based on the distance between the AM and PM tooth shapes.
A manual comparison between the AM and PM records is based on a systematic dental chart completed by some forensic experts In this chart, a number of distinctive features are noted for each tooth individually. These features include properties of the teeth (e.g., tooth present/not present, crown and root morphology and pathology and dental restorations), periodontal tissue features, and anatomical features.
Depending on the number of matches, the forensic expert rejects or confirms the tentative identity. Unlike other biometric characteristics (e.g., fingerprints, iris, etc.), dental identification is complicated by the fact that dental features do change over time. The teeth can change appearance, or can be missing altogether, as a result of dental work or accidents occurring after the AM records are taken.
In fact, for this very reason, although accepted in a court of law, dental based identification is considered less reliable than other biometric methods. But in certain cases (e.g., victims in a major fire), this may be the only available biometric method. From a pattern recognition and computer vision standpoint, the problem of person identification based on dental records can be cast as an image matching and retrieval problem: given a dental image (usually a PM radiograph), we must search the database to find an AM radiograph that best matches with this PM record.
2. Existing Method:
The Identification is done in two Modules:
1. The shape extraction module extracts the shapes of the teeth in the database radiographs and query images.
2. The matching module matches the shapes from the query image to those from the database images.
Then a ranking is produced to show the best matching(s) in the database. The matching is performed in three steps. In the first step, a shape registration method is proposed to align and compute the distance between two teeth on the basis of tooth contours. If the shapes of the dental work are available, they...