A first imaging simulation section in a learning device generates image data that indicates a learning image captured by the imaging section from image data on the learning image, and a second imaging simulation section generates image data that indicates the learning image captured by an imaging section from the image data on the learning image. A plurality of parameter generation sections each generate a characteristic difference correction parameter for making characteristics of student data identical to characteristics of teacher data by learning, assuming one of the generated image data as the teacher data and the other image data as the student data, and the parameter generation sections store the generated characteristic difference correction parameters in a plurality of database sections. A characteristic difference correction section corrects one image data having a lower performance to image data having a high performance, using the stored characteristic difference parameters.