In a MIMO communications system a communication device receives one or more receive signals on at least one receiver port. The inventive filter device is characterized in that the heater is designed with at least one heating circuit that is molded into the filter housing. An interface aperture is inside the battery chamber. Each element exhibits a slight variation in a reticle feature characteristic compared to an adjacent other element in the quasi-periodic structure. Improved classifiers are constructed by aggregating the results for different features, and a network of improved classifiers, in which images are processed by later classifiers according to the results from earlier classifiers, is used.