SUMMARYIn this paper, a cellular neural network (CNN) based locally adaptive scheme is presented for image segmentation and edge detection. It is shown that combining a constrained (linear or non-linear) di usion approach with adaptive morphology leads to a robust segmentation algorithm for an important class of image models. These images are comprised of simple geometrical objects, each having a homogeneous grey-scale level and they might be overlapping. The background illumination is inhomogeneous, the objects are corrupted by additive Gaussian noise and possibly blurred by low-pass-ÿltering-type e ects. Typically, this class has a multimodal (in most cases bimodal) image histogram and no special (easily exploitable) characteristics in the frequency domain. The synthesized analogic (analog and logic) CNN algorithm combines a di usion-type ÿltering with a locally adaptive strategy based on estimating the ÿrst-order (mean) and second-order (variance) statistics. Both PDE-and non-PDE-related di usion schemes are examined and compared in the CNN framework. It is shown that the proposed algorithm with various di usion-type ÿlters o ers a more robust solution than some globally optimal thresholding schemes. All algorithmic steps are realized using nearest-neighbour CNN templates. The VLSI implementation complexity and some robustness issues are carefully analysed and discussed in detail. A number of tests have been completed on original and artiÿcial grey-scale images.