Rectified Photography

qv-l-1-24

 

Quai Vauban – Besançon, France

 

Interior of Butler's Pantry at Hill-stead - Farmington, CT

Interior of Butler’s Pantry at Hill-stead – Farmington, CT

 

The Senate Chamber, NC State Capitol - Raleigh, NC

The Senate Chamber, NC State Capitol – Raleigh, NC

Luzerne County Courthouse - Wilkes-Barre, PA

Luzerne County Courthouse – Wilkes-Barre, PA


 


 

Forced Vertical Lines

A rectified photograph is one that has been distorted in such a way that the photograph more truly resembles the subject it portrays.  This can be done through simple perspective correction using a tilt/shift lens (or digitally) by forcing lines in the photograph that are vertical or parrallel in the real world to be so also in the photograph.

Forced vertical and Parallel Lines

An even more precise way to create a rectified photograph is to use the calibration data associated with a lens+camera body combination used in photogrammetry. This will distort the image in such a way to remove not only parallax distortion but also any lens distortion so that the image is mapped accurately to match a set of 3-D coordinates. When printed (or inserted into a CAD drawing) at the correct resolution the image becomes truly “scale-able”.

Parallax and lens distortion removed

Scale-able photographs (and scale-able regions of photographs) can be cropped and used as stand alone documents – or they can be used as the building blocks for hybrid drawings and mosaic images.

Parallax and lens distortion removed (adjacent view)

In the industry, there is some interchangeability (and this confusion) among the terms “Rectifed photo”, “Ortho-photo”, and “Scale-able photograph”.  It is generally helpful when these type of images are enriched with line drawings -becoming hybrid drawings – which should clarify which portions of an image are “scale-able” and which are not.

See also this blog post.

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