The 57th International Symposium ELMAR-2015, the oldest conference in Europe, will be traditionally held in the beautiful old town Zadar on the Croatian Adriatic coast. While the scientific program is expected to create stimulating professional interaction, the crystal clear Adriatic Sea, warm summer atmosphere and wealth of historic monuments promise a pleasant and memorable stay. During the 57 years of activity ELMAR symposium became a significant scientific conference in the field of multimedia communications, image and video processing, navigation systems, speech and audio processing, telecommunications, wireless communications, electronics in marine, naval architecture, sea ecology, and other advanced research areas. Besides, every year ELMAR symposium gathers specialists of various kinds (government representatives, navy, industry, universities and various business people from the region) to discuss the most recent issues and contribute to appropriate market development in Croatia. The scientific program includes keynote talks by eminent international experts and contributed papers. Papers accepted by two independent reviewers will be published in symposium proceedings available at the symposium and submitted for posting to the IEEE Xplore database. ELMAR-2015 symposium is sponsored by the Croatian Society Electronics in Marine (ELMAR), technically co-sponsored by IEEE Region 8, IEEE Croatia Section, IEEE Croatia Section Chapter of the Signal Processing Society, IEEE Croatia Section Chapter of the Antennas and Propagation Society, IEEE Croatia Section Chapter of the Microwave Theory and Techniques Society, and EURASIP (European Association for Signal Processing).