An information processing device for inspecting a target image that contains an image of an inspection target within an inspection region, the information processing device comprising: a pre-processor configured to perform pre-processing by positioning the target image relative to the inspection region for comparing the target image with a reference image or a plurality of reference images; a first calculator configured to set, in the inspection region, a region of interest and surrounding regions that are adjacent to the region of interest, and calculate a feature value of the region of interest and feature values of the surrounding regions; a second calculator configured to calculate an outlier from comparison of the calculated feature values with feature values of regions corresponding to the region of interest and the surrounding regions in the reference images, the outlier numerically indicating singularity of an image at the region of interest; a determiner configured to calculate, based on the outlier, an indicator to be used for the inspection; a third calculator configured to reduce noise components included in the outlier after the outlier is calculated, wherein the determiner generates the indicator by using the outlier from which the noise components have been cut out, wherein the information processing device further comprises: an interface configured to enable addition of the reference image; and a fifth calculator configured to enable a threshold for the outlier to be externally set, wherein the second calculator updates the feature values for use in calculating the outlier while including the added reference image in the calculation, and calculates the outlier with the updated feature values after the updating and wherein the third calculator is configured to reduce the noise components by setting the outlier that is equal to or less than the set threshold to be zero. a pre-processor configured to perform pre-processing by positioning the target image relative to the inspection region for comparing the target image with a reference image or a plurality of reference images; a first calculator configured to set, in the inspection region, a region of interest and surrounding regions that are adjacent to the region of interest, and calculate a feature value of the region of interest and feature values of the surrounding regions; a second calculator configured to calculate an outlier from comparison of the calculated feature values with feature values of regions corresponding to the region of interest and the surrounding regions in the reference images, the outlier numerically indicating singularity of an image at the region of interest; a determiner configured to calculate, based on the outlier, an indicator to be used for the inspection; a third calculator configured to reduce noise components included in the outlier after the outlier is calculated, wherein the determiner generates the indicator by using the outlier from which the noise components have been cut out, wherein the information processing device further comprises: an interface configured to enable addition of the reference image; and a fifth calculator configured to enable a threshold for the outlier to be externally set, wherein the second calculator updates the feature values for use in calculating the outlier while including the added reference image in the calculation, and calculates the outlier with the updated feature values after the updating and wherein the third calculator is configured to reduce the noise components by setting the outlier that is equal to or less than the set threshold to be zero. an interface configured to enable addition of the reference image; and a fifth calculator configured to enable a threshold for the outlier to be externally set, wherein the second calculator updates the feature values for use in calculating the outlier while including the added reference image in the calculation, and calculates the outlier with the updated feature values after the updating and wherein the third calculator is configured to reduce the noise components by setting the outlier that is equal to or less than the set threshold to be zero.