Guillaume, I understand you suggest that we fit a sensor model using GCPs and apply it instead of using the methods I was suggesting. I remember that we actually tried this method for an Hyperion image on the Andes (lot of relief) and the result was very poor. ref. https://mail.google.com/mail/u/1/#search/label%3Aotb-users+alobolistas/140c98557c22c7c7
Instead, we applied the method described in Pala & Pons using another software and the result was very good. So I would say both methods are not equivalent, but I might be wrong. Note that GCPs on wild areas (with no houses, roads etc) are always scarce, perhaps not enough for a reasonable sensor model, but sufficient for a simple 2nd order polynomial. Agus On Tue, Mar 21, 2017 at 10:02 AM, Guillaume Pasero <[email protected]> wrote: > Hi, > On 03/21/2017 09:18 AM, Agustin Lobo wrote: > > I guess the second. > Examples:http://geog.uoregon.edu/amarcus/geog418/Labs/Lab06_rectification.htm > > The polynomial can be fit and applied using gdal_translate to > incorporate the GCPs and then > gdalwarp r near order 2 > to apply the transformation > > but the way of introducing the GCPs is kind of inconvenient. > > This problem is more about sensor model fitting. You have an image in > sensor geometry and you try to ortho-rectify it on ground based on a set of > GCPs. The OTB already has an application to assess a RPC sensor model based > on GCPs. > > The polynomial model is a particular case of rational model, maybe setting > the denominator coefficients to [1,0,0,...,0] will do the trick. > > Guillaume > > Yes, I agree. But can this be done in practice? Also, is there a tool > in OTB to actually fit such a rational polynomial with prescribed > denominators? > > No, at the moment there is no way to estimate a polynomial transform based > on GCPs. If the transform is already computed, it can be fed into a *.geom > file to act as a RPC model with denominator coefficients set like proposed. > > Anyway, please consider also my suggestion of including the method described > in > Pala, V., and X. Pons. 1995. “Incorporation of Relief in > Polynomial-Based Geometric Correction.” Photogrametrics Engineering & > Remote Sensing 61: > 935–44.https://www.researchgate.net/publication/244485309_Incorporation_of_relief_polynomial-based_geometric_corrections > > The sensor models in OTB (RPC based or physical) should already take into > account elevation. The inverse localization function is modeled like : > (row,col) = F_inv(x,y,z) > > > -- > <http://www.c-s.fr> *Guillaume PASERO* > Responsable technique > *Business Unit ESPACE & GeoInformation - Département Payload Data & > Applications* > > *CS Systèmes d'Information* > Parc de la Grande Plaine - 5, Rue Brindejonc des Moulinais - BP 15872 > 31506 Toulouse Cedex 05 - FRANCE > +33 561 17 64 21 - [email protected] > > -- > -- > Check the OTB FAQ at > http://www.orfeo-toolbox.org/FAQ.html > > You received this message because you are subscribed to the Google > Groups "otb-users" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/otb-users?hl=en > --- > You received this message because you are subscribed to the Google Groups > "otb-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- -- Check the OTB FAQ at http://www.orfeo-toolbox.org/FAQ.html You received this message because you are subscribed to the Google Groups "otb-users" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/otb-users?hl=en --- You received this message because you are subscribed to the Google Groups "otb-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
