Distortion Correction of Data Matrix Symbol Directly Marked on Cylinder Surface

The existing distortion correction methods are not fully suitable the multi-distortion image of Data Matrix symbol directly marked on cylinder surface, so an ellipse-arc grid method is proposed to correct this kind of distortion image. Firstly, two ellipse-arc boundaries and two line boundaries are detected based on the symbol contour point set, Secondly, two groups of ellipse-arc and line are interpolated respectively along the symbol distortion and un-distortion directions and form a data grid, the grid intersection points correspond to the binary values of every data module, they are stored in the standard pattern for decoding. The tests show that the proposed method can make the accuracy rate of the symbol data modules improve to 98.7% when its "L" length doesn\´t exceed 68.75% of cylinder diameter, and the symbol is decoded successfully after the distortion correction. The method promotes full application of directly marked Data Matrix symbol in the product lifecycle real-time tracking.