@@ -23,13 +23,12 @@ Photogrammetry was first documented by the Prussian architect [Albrecht Meydenba
<imgsrc="images/data_model_photogrammetry.png"alt="Data Model of Photogrammetry">
### Accessibility
Unlike other scanning methods that require precise orbital plans or specialized equipment, photogrammetry can be achieved simply by flying a drone in a circular pattern and capturing multiple photos. Utilizing the location data from the drone, one can construct detailed models like the example shown here: 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. This accessibility makes photogrammetry an attractive option for various applications, with results that can be sufficiently accurate depending on the specific requirements.
<imgsrc="images/house_scanning.jpg"alt="House">
### Markers
However, it's essential to note that photogrammetry lacks inherent scale. Without a reference point or prior knowledge of the camera locations, the resulting model lacks a definitive scale, as cameras inherently lack absolute scale information. Therefore, incorporating at least one reference point is crucial. For example, marking a facade with visual markers or known distances, such as pieces of tape, allows for scaling within a 3D modeling program based on these references.
# Stereo Matching
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@@ -42,7 +41,7 @@ However, it's essential to note that photogrammetry lacks inherent scale. Withou
While the analog versions of these techniques have waned in popularity, stereophotogrammetry still has applications for capturing dynamic characteristics of previously difficult to measure systems like running <ahref="https://www.spiedigitallibrary.org/conference-proceedings-of-spie/8348/1/Dynamic-characteristics-of-a-wind-turbine-blade-using-3D-digital/10.1117/12.915377.short?SSO=1">wind turbines</a>.</p>
### When is it useful?
When is it useful?
Photogrammetry is useful for outdoors settings, where all you need is a handheld camera and some patience. In this example, note the loss of quality towards the top, as pixel resolution becomes problematic:
<divclass="sketchfab-embed-wrapper"><iframetitle="Arc de Triomphe - photogrammetry"frameborder="0"allowfullscreen=""mozallowfullscreen="true"webkitallowfullscreen="true"allow="fullscreen; autoplay; vr"xr-spatial-tracking=""execution-while-out-of-viewport=""execution-while-not-rendered=""web-share=""src="https://sketchfab.com/models/65937fd27de647c0a8ac99ce8275c03e/embed"></iframe><pstyle="font-size: 13px; font-weight: normal; margin: 5px; color: #4A4A4A;"><ahref="https://sketchfab.com/3d-models/arc-de-triomphe-photogrammetry-65937fd27de647c0a8ac99ce8275c03e?utm_medium=embed&utm_campaign=share-popup&utm_content=65937fd27de647c0a8ac99ce8275c03e"target="_blank"style="font-weight: bold; color: #1CAAD9;"> Arc de Triomphe - photogrammetry </a> by <ahref="https://sketchfab.com/nicolasdiolez?utm_medium=embed&utm_campaign=share-popup&utm_content=65937fd27de647c0a8ac99ce8275c03e"target="_blank"style="font-weight: bold; color: #1CAAD9;"> Nicolas Diolez </a> on <ahref="https://sketchfab.com?utm_medium=embed&utm_campaign=share-popup&utm_content=65937fd27de647c0a8ac99ce8275c03e"target="_blank"style="font-weight: bold; color: #1CAAD9;">Sketchfab</a></p></div>
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@@ -58,7 +57,7 @@ Depending on the end use application almost any camera will work given there is
Light conditions in the scene are crucial to the quality of the scan. A controlled environment is highly preferred. Precision is improving but can still be completely thrown off by certain light conditions in much the same way LiDar struggles with smooth surfaces.
