A new digital method for the objective comparison of frontal sinuses for identification

Use of the frontal sinuses for identification requires an objective method of comparison to meet Daubert standards. Christensen's application of Elliptical Fourier Analysis and Likelihood Ratios seems to be a viable solution for this problem. The proposed method draws upon this work and attempts to simplify its application. Variation between pairs of digitized sinus tracings was quantified by summing the difference between corresponding measurements taken from a fixed origin to the outer edge of the sinus outlines using Adobe Photoshop CS2. Same-skull and different-skull pairs were used to develop reference distributions from which the probability of unknown pairs coming from the same or a different individual was estimated. Error rates of 0% were achieved. Resulting correlation coefficients demonstrated inter-rater and test-retest reliability. Further refinement of the reference distributions and more rigorous testing of error rates should make this technique applicable to casework.