1. A biological information processor comprising: at least one processor configured to detect an area in which a person is displayed from image information, to extract, from the detected area, feature information which is based on a characteristic portion of a person, to perturb a position of a characteristic point detected in test image information to set a perturbation feature point group indicating positions different from the position where the characteristic point is detected as feature points, to extract second feature information from the perturbation feature point group, to determine, based on the image information, the detected area and a position of the characteristic portion of the extracted feature information, an extraction precision of the feature information indicating whether the characteristic portion of the person is correctly extracted, to calculate a similarity between the feature information and the second feature information indicating a position different from the position where the characteristic portion is detected as a feature, to determine, if the similarity is equal to or larger than a predetermined threshold, that the extraction precision of the feature information indicates that the characteristic portion is not correctly extracted, and to correct, if the extraction precision indicates that the characteristic portion is not correctly extracted, at least the detected area among the image information, the detected area, and the feature information without re-detecting the area and re-extracting the feature information so that the extraction precision is increased.