Summary: The localization and the sizing of 3D flaws within a homogeneous metallic medium is a major task for non-destructive evaluation (NDE). This paper addresses the problem of the reconstruction of such flaws using an efficient binary algorithm. Basically, the method rests on the fact that a simple binary constraint suffices for an accurate and robust reconstruction in the context of NDE. A heuristic minimization, computationally attractive, is designed in order to provide fast reconstructions. The proposed algorithm is compared with standard binary (the iterated conditional mode algorithm) and non-binary (penalized approach with convex potential Gibbs random fields) reconstruction techniques.