lesson 4: reconstructing the situation plans from fisheye distorted photography

edit ~ 0 kommentare/fragen ~ 24. Apr 2015 10:59

Hello Persp.&Photo freaks,

here a preview to our next seminar. We will start preparing and analyzing a photo together before each of you will continue with its own material. there is a useful sequence of steps we should follow:

A Preparation of the Photo

1. optimizing the image will improve its contrast ore lighten dark zones
2. remoove distortions by using the lens correction filter (Objektivkorrektur) or alternatively image trends fisheye hemi 3 demo filter which you can download.
3. Use the filter "Konturen finden" (in Stilisierungsfilter) to get a very transparent image where you can determine object edges much better as in the originate photo.
4. Remoove the watermarks of the demo filter if nessecary.

B Analysis of the photos perspective

1. Find the main point MP of the Photo by intersecting its diagonales
2. Search for pairs of parallel object edges and draw them.
3. Start intersecting the longest pair at first to get its vanishing point..
4. Intersect the next pair to get a second vanishing point.
5. To get a vanishing line connect both vanishing points.
6. Draw a line from both vanishing points to the main point.
7. From each vanishing point draw a line perpendicular to one line of step 6.
8. Intersect the last two lines to get the third vanishing point.

C Reconstruction of the orthogonal views (side and ground) of the photographed objects

D Overlay the reconstructed fragments with a larger plan or satellite view to implement other fragments and reconstruct a wider ranged site.

E Generating a 3D model of the whole scenario with the topographical informations (DIM data).

This is very individual and depends on the special situation

best regards
Prof. Andreas Kästner

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