>The program is not available anymore and I do not have a copy. >I believe it is used more for photo scanning of documents and books >rather than real world images at a longer distance. > >However taking a straight on photo of a picket fence or equally spaced >houses, should be able to produce a similar set of lines. Though one >which an automatic coordinate extraction program would not be able to >directly handle. > >But I understand how the program works in automatically finding the >line crossings of the equally spaced parallel lines, and once it has >determined those coordinates the rest is much like your spread sheet >but with far more coordinates, spread over a larger radial range. > >That allows for better matching by least squares function fitting. >Something IM already does for handing large numbers of 'control >points' than the minimum needed for affine, perspective, or (still >undocumented) polynomial distortions, in pixel coordinates. > > >FYI Polynomial Distortion > -distort polynomial 'order, coordinate-pairs, ....' >Where order is largest X or Y power of for the polynomial >and determines the minimum number of coordinates needed > order function minimum coodinates > 0 constant 1 > 1 affine 3 > 1.5 bilinear 4 > 2 quadratic 6 > 3 cubic 10 > 4 quartic 15 > 5 quintic 21 > >For example a cubic distortion (order 3) >distorts the image using the reverse mapping function > Xsrc = a0 + a1*x + a2*y # affine terms > + a3*x*y # bi-linear term > + a4*x^2 + a5*y^2 # quadratic terms > + a6*x^3 + a7*x^2*y + a8*x*y^2 + a9*y^3 # cubic terms > >and a similar but completely separate Y coordinate mapping function. >
Anthony, Currently your least squares fit only works with X,Y coordinate to fit an X equation and a Y equation. I am not sure you have anything that will work directly with fitting a single polynomial in R=sqrt(X^2+Y^2). Or do you? Fred _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
