marco@cui.UUCP (Marco BALDASSARRE) (04/15/88)
From article <844@agora.uucp> , by rick@agora.uucp ( Rick Coates ) : >A new question: I am interested in mapping one 2d area into another. >The first area may be rectangular, the second a collection of vectors >with four points defined as corresponding to the original rectangle's. >This is a 'rubber sheet' analogy, where you draw a picture on a stretchable >sheet, then deform it. Have you ever thought of using a 3D modelling of bi-dimensional deformations ? Your bi-dimensional deformations - rubber sheet analogy - musst look like this ( locally ! ) : #1 #2 * * * * -------> * * * * This is a special case of the model I had worked on some time ago(where we talk about squatched/stretched edges - *not* determined by four points but by edge- functions ). What about 2D mapping thru bi-linear interpolation of delta_x(x,y) & delta_y(x,y) : ( - the general model is 2D mapping using interpolation of delta_x(x,y) & delta_y(x,y) by ruled/lofted surfaces ...) delta_x delta_y ^ ^ | ^ y | ^ y | / #1 | / #1 |/ |/ .------> x .------> x Where delta_x(x,y) is determined by the difference between x1 & x2 , and delta_y(x,y) is determined by the difference between y1 & y2 , ( x1,x2,y1,y2 known at the 4 discrete locations only ). :-) ____________________________________________________________________________ Marco A. Baldassarre Computer Sciences Center University of Geneva ICBM:46o13'38"[N]/6o7'30"[E]