> As you are using PTlens, how does it decide what 'barrel' correction > parameters it should use? > > I am not certain if IM should do that itself or not. Or prehaps as a > speciallised wrapper operators around distort.
Anthony, I have been working on this issue (with Fred Weinhaus) for some time. The point is that the transformation is fairly simple, its more or less a re-calculation of the radius vector to the image centre by a polynominal approach. The essential thing is the parameters used in this transformation and they are not that easy to fit. (You essentially have a photograph of an object with straight lines and tell you fit algorithm that these are straight.) Tom Niemann has built up a large (crypted) database of camara parameters that PTlens uses. PTlens gets the make and model of the camera as well focal length from the EXIF data within the JPEG photograph. It then chooses the correct parameters for the transformation itself. (The parameters have been determined at several focal lengths for each camera model.) This all is not that easy to implement in any other image manipulation program, even not in IM. Greetings from Germany Wolfgang Hugemann _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
