2D barcodes are two-dimensional graphical patterns that encode information. During encoding there is an important stage named mask modulation the purpose of which is to limit the average gray level of each area of resulting image and to make it suitable for printing and recognition. Since the traditional schemes are mostly based on perceptual template pattern selection and lack formal method and objective evaluation is based on quantitative analysis

resulting non-optimal selection during application. Our task is to objectively and mathematically evaluate the mask modulation. In this paper

based on a 2-dimensional continuous matrix bar code with uncertain capacity

we introduce an evaluation method of graphical patterns based on mathematic statistical model. This evaluation is more impersonal and optimal than the traditional method.