Hello again, after several weeks of work-related absence... Prompted by someone mentioning LCP files and the lens model Adobe implements in their products, http://download.macromedia.com/pub/labs/lensprofile_creator/lensprofile_creator_cameramodel.pdf I have done some internet searches. Interestingly, after some original papers, I discovered that wikipedia has nice write-ups. A few hooks:
Findings: hugin parameters a and c have to be zero. https://en.wikipedia.org/wiki/Optical_aberration cited text in there: "These degrees, named by J. Petzval <https://en.wikipedia.org/wiki/Jozef_Maximili%C3%A1n_Petzval> (*Bericht uber die Ergebnisse einiger dioptrischer Untersuchungen*, Buda Pesth, 1843; *Akad. Sitzber., Wien,* 1857, vols. xxiv. xxvi.) *the numerical orders of the image,* are consequently only odd powers; ..." This is also the result of a rigorous wavefront treatment when the lens is centered ond rotationally symmetric. Seidel-Aberration. https://fr.wikipedia.org/wiki/Distorsion_(optique) The Brown–Conrady model (see wikipedia and references therein) is pretty much at the base of the Adobe model and its parameters. In addition to radial distortion coefficients it also includes tangential distortion coefficients. https://en.wikipedia.org/wiki/Distortion_(optics) The Brown–Conrady parametrisation being also adopted by the USGS. "The New Camera Calibration System at the U. S. Geological Survey" https://www.asprs.org/wp-content/uploads/pers/1992journal/feb/1992_feb_185-188.pdf Interesting reading makes a paper from de Villiers, J. P.; Leuschner, F.W.; Geldenhuys, R. (17–19 November 2008). "Centi-pixel accurate real-time inverse distortion correction" With barrel parameter only you get about 0.3 pixel accuracy, go further and one gets 0.07 pixel accuracy. Hugin is currently at the 0.3 level only. Hence I advocate to include more parameters from the Brown–Conrady model. Currently only K1 is there in form of the ptx b parameter. To include at the very least parameter K2 into the hugin lens model. Reasonably I suggest parameters K2 and K3 plus tangential coefficients P1 and P2. Best regards Klaus -- A list of frequently asked questions is available at: http://wiki.panotools.org/Hugin_FAQ --- You received this message because you are subscribed to the Google Groups "hugin and other free panoramic software" group. To unsubscribe from this group and stop receiving emails from it, send an email to hugin-ptx+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/hugin-ptx/9e6bae9b-85ff-4076-bd81-4dfe9234d92e%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
