This paper presents a low-complexity interpolation method that minimizes image quality losses at edges, which are easily perceivable by the human eye. Deinterlacing, which converts an interlaced video into a progressive video, is a problem in image interpolation that doubles the number of vertical lines. Applying averaging, or any linear algorithm, achieves time-efficient deinterlacing but produces artifacts. However, applying other complex methods tends to reduce unwanted artifacts but at the cost of high computation time. The proposed deinterlacing scheme is based on an algorithm called “edge slope tracing” which simply predicts the slope on the basis of information on adjacent slopes. Predicted slopes are used to perform deinterlacing in slope-based line averaging. The simulation results show that this scheme provides better results and reduces complexity compared to conventional state-of-the-art algorithms.