Reference image generation method and pattern inspection method

A pattern inspection method comprising:

• reading design data of a plurality of patterns formed on a sample and characteristic information indicating characteristics of each of the patterns from a storage device, the characteristic information being additionally written in the design data;
• dividing a pattern formed region of the sample on which the patterns are formed, into a plurality of regions where the characteristics within each region are of a similar pattern type and characteristics of different of the plurality of regions are different from each other, on a basis of the characteristic information;
• calculating parameter information according to the characteristics with respect to each of the regions, where the parameter information is filter coefficients, so that each of the plurality of regions has a respective filter characteristic, for generating a reference image by calculating with the design data to be used in an inspection of the patterns;
• generating the reference image from the design data on a basis of the calculated parameter information;
• and
• inspecting a defect of the patterns on a basis of the reference image and an optical image obtained by imaging the sample.