The  Covered  Arcades of  Paris
   Les Passages Couverts de Paris

Digital Photographic Enhancement Techniques

Panoramic Stitching                        










Panoramic Stitching is a technique of assembling multiple photos, shot in different directions from a single vantage point, to produce one very wide angle image. Each photo overlaps its neighbors to allow for manual or computer-generated alignment.

Traditional photography has long used wide angle lenses and panoramic methods, ranging from the fisheye, which gives a 180 degree view, to the swiveling lens, which paints film on a curved focal plane. However, optical projection calculations always introduce distortions in images as one gets further away from the axis of vision. The result is increased curvature of straight lines towards the periphery.

The work presented here massages and minimizes these distortions as much as possible, attempting to portray the space as the eye perceives it. The intention of this extensive computer manipulation is to present, in two dimensions, a strong sense of envelopment and enclosure, similar to what one senses while in these unique and historic urban spaces.

Distortion correction is done manually in certain situations by compositing elements from the original photograph (top row, right). This becomes necessary, in particular, with rounded  objects in the corners of the frame.
[original computer-generated lamp, above right; corrected lamp, left] 

The Panoramic Stitching process allows the photographer to set the “eye level” of the image to produce a traditional, “two  point perspective,”  a standard for architectural photography, where  all vertical lines are parallel.  This is similar to the correction performed by tilting the back plane of a view camera.

Eight images are combined into one picture for this print of the Galerie Vivienne. Each of those eight images is generated by combining three camera exposures for expanded tonal range, known as HDR (High Dynamic Range).