Image annotation: Then and now

Automatic image annotation (AIA) plays a vital role in dealing with the exponentially growing digital images. Image annotation helps in effective retrieval, organization, classification, auto-illustration, etc. of the image. It started in early 1990. However, in the last three decades, there has been extensive research in AIA, and various new approaches have been advanced. In this article, we review more than 200 references related to image annotation proposed in the last three decades. This paper is an attempt to discuss predominant approaches, its constraints and ways to deal. Each segment of the article exhibits a discourse to expound the finding and future research directions and their hurdles. This paper also presents performance evaluation measures with relevant and influential image annotation database. (C) 2018 Elsevier B.V. All rights reserved.