A comprehensive review of froth surface monitoring as an aid for grade and recovery prediction of flotation process. Part A: structural features

Digital image processing system is a promising technology for obtaining process-related information and well accepted in mineral processing industries as a fast, non-invasive and low-cost tool for quality evaluation of flotation process. The structural, textural and dynamic features of froth surface appearance include vital information about process status, which can be employed as a useful index for the evaluation of the flotation performance. A large number of features extraction techniques have been proposed over the last years and understanding digital imaging and selecting a proper technique for the desired application are very important. The goal of this two-part series is to compile an up-to-date review regarding the most common techniques of features extraction from froth images and to present their major advantages, limitations, and applications in flotation process, with particular focus on prediction of concentrate grade and recovery. Part 1 of this review focusses on the structural features of froth images (bubble shape and size distribution) and the relationship between them and process conditions, while Part 2 presents textural and dynamic features. Also, Part 2 discusses estimation methods of concentrate grade and recovery with the froth surface measurable attributes. This work can make significant contributions toward the development of on-line control systems on the basis of machine vision.