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# Passive scanning
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## Table of contents
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1. TOC
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# Multiview

# Photogrammetry
Photogrammetry is the collection and organization of reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant imagery and other phenomena.

<p>Photogrammetry was first documented by the Prussian architect <a href="https://opus4.kobv.de/opus4-btu/files/749/db186714.pdf">Albrecht Meydenbauer</a> in 1867. Since then it has been used for everything from simple measurement or color sampling to record complex 3d <a href="https://en.wikipedia.org/wiki/Motion_field">motion fields</a>.</p>

<p><img src="images/data_model_photogrammetry.png" alt="Data Model of Photogrammetry"></p>

<p>A typical medium resolution aerial photogrammetry scan of a barn. With 50-100 images a reasonably accurate model can be produced. Such models are often used in surveying and restoration projects from the scale of hand helf objects to cities.</p>

<p><img src="images/house_scanning.jpg" alt="House"></p>

# Stereo Matching and Photogrammetry


<p>Early uses in stereophotogrammetry, the estimation of 3d coordinates from measurements taken from two or more images through the identification of common points. This technology was used throughout the early 20th century for generating topographic maps.</p>

<p><img src="images/stereo_plotter.jpg" alt="StereoPlotter"></p>


# Key Benefits



# Key Challenges

# Tools

# Apps

# Camera Equations