Two-Stage Enhancement of Dry Fingerprint Images Using Intensity Channel Division and Estimation of Local Ridge Orientation and Frequency

Quality of finger prints play a major role in justifying the performance of any automatic finger print identification or verification system specially in extracting minutiae. This chapter deals with the enhancement of dry fingerprints as it is very crucial in forensics. This enhancement algorithm improves the quality of dry fingerprints adaptively in two stages. First-stage enhancement is done using intensity channel division approach followed by the second, which is based on the presence of ridge regions in the image. The ridge regions recognized in the dry fingerprint image are normalized and hence, ridge orientations are determined. Finally, estimation of local ridge frequencies is carried out along with the application of relative filters with appropriate orientation and frequencies.