Real-time image segmentation for visual inspection of pharmaceutical tablets

Visual appearance is an important quality factor of pharmaceutical tablets. Due to the vast quantities of produced tablets and high-quality requirements, pharmaceutical companies are interested in employing automated systems for real-time visual tablet inspection with the speeds of up to 100 tablets per second. Such systems require reliable tablet manipulation, illumination, image acquisition, tablet image analysis, classification, and sorting system. Tablet image segmentation, in which each tablet image is partitioned into the tablet region and background, is the first and very important step in tablet image analysis. It this paper, we propose a novel real-time segmentation method for grey-level images that is based on border tracking. The proposed method was designed to be accurate, robust, and computationally undemanding. The performances of the method were objectively assessed on a large number of simulated and real tablet images. The obtained results indicated high reliability, accuracy, and speed. The 100% reliability was obtained for segmentation of real images of pharmaceutical tablets, while the segmentation times were no more than 1.5 ms or 15% of the whole time available for tablet image analysis. As such, the proposed method proved feasible for real-time visual quality inspection of pharmaceutical tablets. Based on just a few assumptions that are usually fulfilled, the method may be a valuable segmentation tool for many other visual quality inspection applications.