A method for forming a dielectric layer is provided. The method comprises receiving radio capacity information of the radio cell, receiving transport capacity information on transport network, the transport network being used for connecting the base stations of the radio network to a core network. After summing a luminance Distribution for each area of the image, which is a feature amount, while uniformly selecting picture elements, a reevaluation is performed by a weighting determined for each area, and a luminance distribution, strongly influenced by the luminance distribution of the photographed object is thus obtained with uniform sampling.