Figure 2

Transmission scheme for barcodes based on watermark codes. Consisting of three blocks: 1) outer coder, encoding index words c as code words of a linear code \(\mathcal C_{1}[\mathbb F_{q_{1}},n_{1}, k_{1}]\) and soft-decoder \(\mathcal D_{1}\). 2) inner coder, with inner code \(\mathcal C_{2}\) (for sparse sequence representation), decoder \(\mathcal D_{2}\) (providing likelihood values) and watermark sequence w (known to encoder and decoder). 3) embedding of barcodes in random context and channel with insertion, deletion and substitution errors.