Virtual Humanities 1: Archive Project Launch

Immersive environments are one of the newest areas of DH experimentation. 3D simulation, Virtual Reality and Augmented Reality were until recently only accessible with high end hardware and produced end products that were so large they were hard to deliver over the internet. As the technology improves, internet bandwidth grows, and the computers in our pockets get more and more sophisticated, these projects are now coming into their own.

In the past week, you’ve gotten a brief introduction to digital collections and metadata through the collection management platform Omeka and our Digital Objects of Carleton sample site featuring archive objects. Today, we are taking a deeper dive into the Carleton College Archives and its shiny new database to help work on a class project 3D modeling and exhibiting objects from the archives. This class project will both help jumpstart the archives’ effort to create a 3D gallery of their collections and serve as an example of the type of project you might want to do for your final project.

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3D Collections and Photogrammetry

There has been a large initiative among museums around the world to create 3D versions of objects in their collections. Among these include the British Museum, which has made hundreds of scans publicly viewable on the popular 3D modeling site SketchFab, and the Smithsonian, which has designed several online 3D exhibits (including this creepy one of Abraham Lincoln’s death mask!).

In addition to high-tech laser scanning, many of these models are using a method known as Photogrammetry, which creates 3D mesh models from photographs.

Photogrammetry consists of taking multiple overlapping photographs and deriving measurements from them to create 3D models of objects or scenes. The basic principle is quite similar to the way many cameras allow you to create a panorama by stitching together overlapping photographs into a 2D mosaic. Photogrammetry takes the concept one step further by using the position of the camera as it moves through 3D space to estimate X, Y and Z coordinates for each pixel of the original image; for that it is also known as structure from motion or SfM.

We will learn how to process and build a Photogrammetry model next class. For today, however, we will focus on the most important step: taking good photos.

Photogrammetry relies upon having enough photographs with sufficient information for the algorithms to stitch images together and extract 3D geometry from them. You can do this using any camera, including the one on your smart phone!

In-Class Exercise: Choose your own Photogrammetry Adventure

There are an increasing number of methods for creating photogrammetry models in the market, and we are going to experiment with several of them and compare the results. Some of these methods require dedicated local hardware with lots of RAM and advanced graphics processing capabilities, others are cloud-based which offer speed and ease of use at the cost of some control over your data and the details of the process.

We will explore the following methods for creating photogrammetric models:

1. Scaniverse (an app that leverages the latest camera and LiDAR scanner technology of iOS devices)
2. Polycam (an app that works on any phone and can use photos or LiDAR to process and edit models)
3. Agisoft MetaShape (the venerable desktop-based solution to process photos)
4. Autodesk ReCap Photo (a cloud-based solution run from the desktop that integrates with other Autodesk offerings)

Options 3 and 4 we will go over in class the next class and you will complete for Sunday’s lab.

Today, you will form groups around an object, and each member of the group will try a different method. Some of these are quicker than others, and we will compare and clean up the results in class next week to share the best models with the Archives.

1) Using Phone Apps

• 1 team member will download and install each of the apps, and follow the tutorials linked below
• The others will use the lights on their phones to cast side lighting on the object — DO NOT MOVE
• These apps will process the models live and allow you to share and export results almost immediately

2) Taking Photos

• 1 team member will take photos with their phone camera
• The others will use the lights on their phones to cast side lighting on the object to try to even out the darker parts of the lighting situation — DO NOT MOVE
• These photos will be used for desktop applications and data recording for future proofing

The most important step in photogrammetry is collecting data: i.e. taking good photographs that will have sufficient information for the algorithms to stitch images together and extract 3D geometry from them.

With a mobile phone camera, you’ll want to make sure you follow these guidelines:

• Have your scene well and consistently lit — DO NOT CHANGE LIGHTING between shots.
• Turn off the flash — because, again, DO NOT CHANGE LIGHTING between shots
• Use the standard photo settings rather than a “portrait” mode or similar. You want deep focus
  • If Macro mode turns on, turn it off
• Have the object fill as much of the frame as you can
• Start at one point and circle the object, overlapping photos by ~50%
• Repeat at multiple heights to get full coverage
• Take several close up shots to get shadowed areas and detailed textures — but DO NOT CHANGE camera settings, zoom, etc.
• If possible, get shots of the top and bottom of the object for full 360 degree coverage

3) Export and Organize your photos

Follow the assignment instructions below to create a folder to start gathering photos and exports for processing.

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