Printing medium movement amount detection device, and error information production method

A movement amount detection device comprising:

• an illumination unit configured to illuminate one side of a medium;
• an image acquisition unit configured to capture a first image and a second image of the one side of the medium conveyed in a state of being illuminated by the illumination unit to acquire the images;
• an estimated movement amount calculation section configured to determine a similar region whose characteristic is most similar to a characteristic of a region to be matched, which is set within the first image, within the second image based on a shadow corresponding to a bump on the one side of the medium in the state of being illuminated by the illumination unit, and to calculate an estimated movement amount of the medium from a positional relation between the region to be matched and the similar region;
• an error information acquisition section configured to acquire error information indicating a correspondence between error in the estimated movement amount attributable to an angle of light directed at the medium by the illumination unit and the estimated movement amount;
• and
• a movement amount calculation section configured to correct the estimated movement amount and to calculate the movement amount of the medium between a point when the first image is captured and a point when the second image is captured.