This volume constitutes the refereed proceedings of the 4th Iberian Conference on Pattern Recognition and Image Analysis, IbPRIA 2009, held in Povoa de Varzim, Portugal in June 2009.

The 33 revised full papers and 29 revised poster papers presented together with 3 invited talks were carefully reviewed and selected from 106 submissions. The papers are organized in topical sections on computer vision, image analysis and processing, as well as pattern recognition.

The two-volume set LNCS 4477 and 4478 constitutes the refereed proceedings of the Third Iberian Conference on Pattern Recognition and Image Analysis, IbPRIA 2007, held in Girona, Spain in June 2007.

The 48 revised full papers and 108 revised poster papers presented together with 3 invited talks were carefully reviewed and selected from 328 submissions. The papers are organized in topical sections on pattern recognition, human language technology, special architectures and industrial applications, motion analysis, image analysis, biomedical applications, shape and texture analysis, 3D, as well as image coding and processing.