Anomaly detection apparatus, method, and storage medium

An anomaly detection method performed by a processor, the anomaly detection method comprising:

• acquiring a first sample that is a subject for anomaly detection;
• generating, using a trained model, a first text from the first sample, the first text representing a content of the first sample;
• determining whether or not the first sample has an anomaly based on a statistic associated with all or a part of the first text in a text information dictionary, the text information dictionary associating all or a part of a second text representing a content of a second sample included in training data with a statistic related to a degree of appearance of all or a part of the second text in the training data;
• and
• outputting a determination result of whether or not the first sample has an anomaly.

A non-transitory computer readable storage medium including computer executable instructions, wherein the instructions, when executed by a processor, cause the processor to perform operations comprising:

• acquiring a first sample that is a subject for anomaly detection;
• generating, using a trained model, a first text from the first sample, the first text representing a content of the first sample;
• determining whether or not the first sample has an anomaly based on a statistic associated with all or a part of the first text in a text information dictionary, the text information dictionary associating all or a part of a second text representing a content of a second sample included in training data with a statistic related to a degree of appearance of all or a part of the second text in the training data;
• and
• outputting a determination result of whether or not the first sample has an anomaly.