deda_extract_yd

deda_extract_yd [options] file

deda_extract_yd isolates the yellow tracking dots on a colour-laser scan and measures their grid. It prints the detected pattern as four numbers (two integers and two floats) when measurement succeeds. Use it when deda_parse_print does not recognise the layout and the dot positions themselves are what you need.--debug saves the intermediate masks and crops. --expose ends once the dots have been separated from the page.

file

Scan to analyse.

Resolution of the scan. 0, the default, asks the reader to detect it. Detection that fails assumes an A4 page and prints the assumption on standard error.

Inked-area mask, used when file is a monochrome image of the dots rather than a colour scan. Requires -d with a non-zero resolution. Cannot be combined with --expose.

Write the exposed-dot image and return before the grid is measured.

Do not crop the page down to the region that contains dots.

Translation code as four comma-separated values: two integers and two floats. A question mark leaves that value unset.

Write intermediate images named **yd_*.png** in the working directory.

Repeat to print more of the detection steps.

The reader expects a colour scan in which the yellow dots are still visible. JPEG compression, aggressive thresholding, and a wrong DPI hide or shift the grid. If the file has no usable DPI metadata, the command assumes an A4 page and says so on standard error.--debug writes **yd_*.png** files in the current directory and will overwrite an older file of the same name.

deda_extract_yd is part of DEDA, written by Timo Richter and Stephan Escher and described in their 2018 paper on forensic analysis and anonymisation of printed documents.

deda_parse_print(1), deda_compare_prints(1), deda_anonmask_create(1)

Source code