Tulon wrote:Does this mean that software like qprc (viewtopic.php?f=3&t=784), PhotoShop or DxO are useless and that is better to do de-keystonne in ScanTailor?
Scan Tailor and any other software use the same mathematical model for dekeystoning - it's called homographic transformation. However, there are a couple of reasons you may want to correct keystoning before Scan Tailor:
1. Programs relying on pre-calibration (with a checkboard pattern, QR codes, etc.) won't generally make mistakes.
2. Content box and margins don't play well with significant keystoning, so either prepare for more manual adjustments or do your dekeystoning before Scan Tailor.