Electroluminescence and photoluminescence imaging provide spatially resolved lifetime information of solar cells with short measurement time. Its high resolution feature validates good visualization of local defects. However, the luminescence image for finished cells is a 2-dimensional image. An extension to 3-dimensional image should be included. This paper proposed a fast technique for separating front and bulk effects. "Front" in this paper refers to front surface, emitter and junction. Its quality can be varied a lot during processing and it is a most interesting region for most of the cells. Experimental results show that the method achieved a clear separation for various cells. It helped to optimize the cell processing and developing techniques. Therefore, it could become a popular characterization technique in the laboratory based on its fast, reliable and 3-demensional spatially resolved features. Crown Copyright (C) 2014 Published by Elsevier B.V. All rights reserved.