Measuring separation of patterns, and use thereof for determining printer characteristics

An apparatus for determining a location of a graphical object printed onto a print medium, said graphical object comprising a plurality of object marks, the apparatus comprising:

• a two-dimensional reference pattern glass having a pre-defined degree of accuracy for superposing over the printed graphical object, the two-dimensional reference pattern comprising a plurality of pattern marks;
• a scanner for scanning the superposed printed graphical object and reference pattern to produce a scanned image;
• a memory for storing a program;
• and
• a processor for executing the program, said program comprising:
• code for determining a location coordinate of the graphical object in the scanned image;
• and
• code for refining the location coordinate dependent upon the scanned reference pattern to determine a reference pattern coordinate associated with the location coordinate, said reference pattern coordinate defining the location of the graphical object;
• wherein said graphical object is adapted to have a separation area in the vicinity of the location coordinate to thereby minimize occlusion of the pattern marks by the object marks in the vicinity of the reference pattern coordinate.

A non-transitory computer readable storage medium having recorded thereon computer executable code of a computer program for directing a processor to execute a method for determining a location of a graphical object printed onto a print medium, said graphical object comprising a plurality of object marks, wherein a two-dimensional reference pattern having a pre-defined degree of accuracy is superimposed over the printed graphical object, the two-dimensional reference pattern comprising a plurality of pattern marks, the program comprising:

• code for scanning the superposed printed graphical object and the two-dimensional reference pattern having the pre-defined degree of accuracy, to produce a scanned image;
• code for determining a location coordinate of the graphical object in the scanned image;
• and
• code for refining the location coordinate dependent upon the scanned reference pattern to determine a reference pattern coordinate associated with the location coordinate, said reference pattern coordinate defining the location of the graphical object;
• wherein said graphical object is adapted to have a separation area in the vicinity of the location coordinate to thereby minimize occlusion of the pattern marks by the object marks in the vicinity of the reference pattern coordinate.