Patent claim: Method for printing on a media object supported by a flat bed of a printer the printer comprising a print head that is controlled to move over the media object using print head coordinates and a camera above the flat bed the method comprising the steps of a detecting a media object on the flat bed surface of the printer by means of a digital camera image captured by the camera b deriving camera coordinates of the media object in the digital camera image c converting the camera coordinates indicating a shape and a size of the media object into print head coordinates of the media object using a mapping table d arranging a digital target image relative to the print head coordinates of the media object and e printing the digital target image on the media object by ejecting recording material on the media object from the print head wherein the mapping table is established by applying the steps of f printing a reference image on a substrate supported by the flat bed surface the reference image comprising geometric patterns which are defined in print head coordinates g capturing a reference digital camera image of the printed reference image by means of the camera detecting the geometric patterns in the reference digital camera image h expressing the detected geometric patterns in reference camera coordinates and i determining a relation between the reference camera coordinates and the print head coordinates of the detected geometry patterns.

Related passage: In order to achieve the abovedescribed object a printing device according to the present invention includes a table including a top surface on which one or a plurality of printing subjects having a rectangular or a substantially rectangular shape are to be placed a printing head located above the top surface of the table the printing head being movable with respect to the top surface of the table in an Xaxis direction and a Yaxis direction the Xaxis direction and the Yaxis direction being perpendicular to a vertical axis an image capturing device that captures an image of the top surface of the table a location area acquisition unit that acquires a background image captured by the image capturing device of the top surface on which a checkered pattern is printed and no printing subject is placed and a foreground image captured by the image capturing device of the top surface on which the one or plurality of printing subjects are placed and acquires a location area for each of the printing subjects from the background image and the foreground image a rough edge image acquisition unit that acquires a first edge image showing a rough contour of the each printing subject in the location area acquired by the location area acquisition unit a precise edge image acquisition unit that acquires from the first edge image a second edge image showing a precise contour of the each printing subject a location position acquisition unit that acquires a position and a posture of the each printing subject from the second edge image a calculation unit that calculates a transform matrix usable to normalize the each printing subject such that the each printing subject assumes apredetermined posture the transform matrix being calculated based on the position and the posture of the each printing subject acquired by the location position acquisition unit and a printing data creation unit that calculates an inverse matrix of the transform matrix calculated by the calculation unit and transforms by use of the inverse matrix printing data edited by an operator to create printing data actually usable for printing.