Arrangements for inspecting a specimen on which plural patterns are formed; capturing a first image of a first area; capturing a second image of a second area in which patterns which are essentially the same with the patterns formed in the first area; creating data relating to corresponding pixels of the first and second images, for each pixel; determining a threshold for each pixel for detecting defects directly in accordance with the first and second images; and detecting defects on the specimen by processing the first and second images by using the threshold for each pixel and information of a scattered diagram of brightness of the first and second images, wherein the threshold is determined by using information of brightness of a local region of at least one of the first and second images, with the local region including an aimed pixel and peripheral pixels of the aimed pixel.