Data Matrix Code reconstruction from the image acquired by the multilayered waveguide optical card

The Data Matrix Code (DMC) recorded by the multilayered waveguide optical card (MWOC) is distorted seriously in the fabrication and readout procedure. Digital image processing is applied to the acquired image from the WMOC to decrease the distortion introduced in the two-dimensional data recoding and reading procedures. In this paper, some digital image processing algorithms are put forward such as with Butterworth Lowpass Filter (BLPF) technique to reduce noise in the frequency domain, with implementing first order digital derivative to the sum profile of the gray-level in the horizontal and vertical lines to trace the contour of the whole DMC from the image to realize image segmentation, with the region filling with 0 or 1 after the calculation of the side size of the code bit and its center coordinate as well as the regions division to satisfy the code bit blocking. With these processing, we can restore the round code point to square shape. And the experimental result shows the feasibilty of the proposed reconstruction methodology and DMC can be decoded correctly and effectively.