If the sundial is vertical you can use the following method: - Transform prospectively the image with Photoshop, up to have the image as if it were photographed in front. - A little experience and some attempts are sufficient
- Now the image of the sundial is seen in front, but if the height of the camera lens was different from the center of the dial, the height is not correct and the image should be stretched vertically to bring it to the exact height. - This can be done with the "trial and error" method by checking the angles or, better method, using the program by Gian Casalegno "Orologi Solari - Sundials" http://digilander.libero.it/orologi.solari/ The program gives the possibility to search for the Latitude, the position of the style, its length and also the vertical deformation. You should use the option: "Tools - Reverse Engineering - vertical distortion" With a little practice you can get the information you need. Best wishes Gianni Ferrari 2012/1/11 Shadows Pro <[email protected]> > Hi Darek and all > > There is a feature in my program Shadows Pro to reverse engineer a vertical > sundial from its picture. It does not correct aberrations due to the camera > objective but if the picture is taken exactly in front, it works pretty > well. > > You can see a screen copy on this page: > www.shadowspro.com/en/gallery12.html > > > Regards > François > www.shadowspro.com > > > -----Message d'origine----- > De : [email protected] [mailto:[email protected]] De > la part de Darek Oczki > Envoyé : mercredi 11 janvier 2012 00:32 > À : [email protected] > Objet : 2 questions: declination & animation > > Dear Diallists > > I've got two practical questions: > > 1. Let's say I have a photograph of a sundial. I do not know where it was > originally located. Is there a way to discover the values of the > declination > and latitude it was designed for? There are clear hour and declination > lines > on the dial. > > 2. A friend of mine is helping a student in an attampt to reconstruct an > old > missing dial. They need a software which allows to make an animation of a > shadow's path over the dial. Is there anything that would help them? > > I would be most grateful for any suggestions. > > -- > Best regards > Darek Oczki > 52N 21E > Warsaw, Poland > > GNOMONIKA.pl > Sundials in Poland > http://gnomonika.pl > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > -- --------------------- Ing. Gianni Ferrari Lat. 44;38,18.5N Long. 10;56,05.3E [email protected]
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