Patent ID: 8167395

Claim:
A method of creating a test pattern with a plurality of printheads of a three-dimensional printer, the method comprising: defining an area on a build surface for receiving the test pattern, by printing a contrast-enhancing sublayer on the build surface by (i) spreading a layer of build material on the area of the build surface, (ii) printing the area on the build material layer in a solid, high contrast color using at least one printhead and (iii) overlaying the printed area with at least one unprinted layer of build material; selecting a reference printhead capable of printing with a high contrast; printing a plurality of reference lines with the reference printhead on the unprinted layer of build material; printing a plurality of test lines proximate to the reference lines with at least one of the remaining printheads; and scanning the test and reference lines to determine a deviation of at least one of the test lines from a desired position by determining a harmonic content of the test and reference lines of at least one frequency.