Fingerprint Image Preprocessing and Feature Extraction Algorithms

Building upon existing frameworks and leveraging inherent fingerprint characteristics, we have developed a more complete set of fingerprint image preprocessing and feature extraction algorithms. Key algorithmic improvements encompass advanced ridge frequency estimation techniques using Fourier transform analysis, enhanced binary image denoising through morphological closing operations, and the introduction of a novel pseudo-feature filtering method based on neighborhood connectivity analysis. The implementation includes threshold-based segmentation algorithms and minutiae validation checks using directional field consistency. Validation tests performed on hundreds of fingerprint images with varying quality levels yield satisfactory results, demonstrating robust performance across different image conditions. Core algorithms feature adaptive thresholding for binarization and ridge thinning operations using Zhang-Suen parallel thinning methodology. Keywords: fingerprint; preprocessing; feature extraction; algorithm enhancement; image quality assessment.