S. S. Bhatlawande, J. V. Kulkarni, P.P.G.S.M.D.S.S.P.H.K.A. 2020. Development of Prototype for Obstacle Detection for Visually Impaired using Defocus Measure. International Journal of Advanced Science and Technology. 29, 3 (Mar. 2020), 5566 - 5582.