Photogrammetry of a Shiny Object

Photogrammetry is the process of taking multiple images of an object, and processing the images with a computer, in order to create a textured 3D model of the object. These 3D models can then be used to create new experiences on the Web, in Augmented Reality & Virtual Reality, or printed in 3D as a physical object.

This blog post is technical in nature, and goes in-depth on the efforts put into a recent project.

Image of the trophy from the camera used to do the photogrammetry

Image of the trophy from the camera used to do the photogrammetry

Behind the scenes photo of the trophy on vinyl background

Zoran and I tried to do a photogrammetry scan of this Coffee Maker/trophy. It is a highly reflective surface, and has many curves as well, so we knew this would be challenging. Zoran tried photographing it in the 32″x32″ light box, but the trophy was very large, and there were unflattering reflections resulting from the white and silver sides of the light box, but also from the hole in the front, as the trophy reflects the camera as well.

We then tried setting it up on the white vinyl on a table top, holding the vinyl up with a C stand arm. The white was nice for behind the trophy, giving it nice contrast, but because it was a small piece of vinyl, it created an unflattering reflection in the bottom of the cup, similar to the reflection above. For lighting, we used two Litepanels Gemini 2×1, one with a softbox, and one without, to see if there was any significant difference. We couldn’t detect one.

The black vinyl had a similar problem, so we tried putting the trophy directly on the floor, using a 6×6 black flag that we hoped would be less reflective than the vinyl. We hung the vinyl behind the trophy.

This kind of worked, but the text on the trophy was really hard to read, so we put a white card on the floor, and that helped make the text more readable, but the white card was too small, only making some of the text more readable, despite being about a 3’x5′ board.

Wider behind the scenes shot of the trophy, showing lighting, camera and backdrops.

To scan a one-of-a-kind artifact like this, as-is, requires a complicated setup.

  • One option would be to construct a larger white lightbox, and light it from the outside through diffused white fabric, and obscuring the lens when it peers through the fabric.
    • Something that could help would be a two way mirror in front of the lens to block the reflection of the lens, though this might result in seeing the trophy instead.
    • We could also be more creative in our lighting, perhaps lighting it directly from above, and using the tent/lightbox to illuminate it from the sides by reflection off the fabric.
    • One thing to consider is that the smaller the diameter of the “tube”, the smaller the reflection, but at some point the reflection is less of an object, and more just a specular highlight. It may be difficult to get an even lighting over the whole object because of this.
    • We may be able to build a larger lightbox with our newly acquired 6×6 frames and rags, but we have not tried. We could suspend the light source over the lightbox using the Menace arm kit. This would take up a lot more space in the studio than the current lightbox does, however.
  • Another option would be to get the top parts of the trophy looking good, perhaps using a polarizing filter on either the camera, lights, or both. [see the sketchfab article below] Then photograph it from all angles, then light it so the middle looks good, then photograph it from all angles, and then light it so the bottom looks good, then photograph it from all angles. Then the three images for * each* camera and turntable position would need to be combined into one image, and then those composite images sent to the photogrammetry software for processing. This would require very precise camera and lighting positioning.
  • If we would be able to alter the artifact, we could spray it with one of these sprays:

Look Your Best Recording Remotely

Prior to the pandemic, our team often recorded on-location or in our studio, using our own cameras and lighting equipment. In March, like many others, we had to shift to a work-from-home model while sheltering-in-place. Many clients had to use their home environment for recording their own video content.

The MTI team produced this video in the early weeks of sheltering-in-place to aid our colleagues, particularly faculty who are creating course lectures, in turning their at-home environment into a set for recording video content:

Since this video was produced, we’ve noticed there are still common pitfalls many recordings fall into. Fortunately, they have easy solutions. Here is a non-exhaustive list of issues you can look out for when recording yourself.

The Camera Is Too Low

Raising your computer’s camera to the same height as your eyes will produce a better image for presenting yourself to an audience. Not sure if it feels like the correct height? One easy tell is if you can see the ceiling in your image. See the ceiling? Your camera is still too low! Add another book/box or two to raise it up.

Poor Eye Line

Realistically, it’s difficult to maintain constant eye contact with your camera. In some cases, the camera (especially on laptops) is so small it feels like it’s not even there. To make matters more challenging, you can’t be expected to memorize or perfectly execute every lecture you need to record. It can help to position your outline or script near the top of your screen, as close as possible to the camera. Place yourself further back from your screen to help minimize eye movement. You can also record your video in separate clips to focus on individual chunks and use slides or other graphics on screen to strategically hide edits.

Poor Audio Quality

Are you recording audio for a powerpoint presentation, or your options for recording are limited to a platform that significantly compresses audio? You can vastly improve the audio quality of your recording by using your phone to record yourself!

Missing/Undesired Results for Video, Presentation, or Audio Content

Especially if you’re recording for the first time, do a brief 5 second test with your setup. Play it back to make sure everything you want to capture looks and sounds as you prefer. A brief test will go a LONG way to prevent you from re-recording an entire lecture.

In addition to these tips, remember that everyday occurrences such as outside noise, family, pets, and roommates have become a regular part of connecting with audiences virtually. Reduce distractions where and when you can, but in some circumstances there may be instances outside of your control.

COVID-19 has really impacted the way we work and think about working from home. We hope this helps you with your own recording, teaching, and learning.

2019 Leopold Lecture with Rep. Adam Schiff

Addressing a full audience last night in Cahn Auditorium, California Rep. Adam Schiff, Chairman of the House Intelligence Committee, delivered this year’s annual Leopold Lecture. He addressed modern concerns such as emerging deepfake technology, the position of the United States as a bastion of freedom, and spoke directly to the most recent actions by President Donald Trump.

Northwestern IT was on site to live stream the evening’s event in collaboration with Global Marketing and the Weinberg College of Arts and Sciences.

Class of 2023 and Transfers Aerial Photo

Welcome Class of 2023 and Transfer Students! Last Friday we were delighted to join about 2000 wildcats to create this year’s...
Read More

Robotics Filming in Tech

Last week, we filmed in the new Robotics and Biosystems Center space in the new AB Fill in Tech, interviewing faculty...
Read More

Media & Technology Innovation at Commencement 2019

Northwestern hosted its 161st annual Commencement this past weekend. Working with the Commencement Office and TC Furlong, Northwestern IT provided a...
Read More

Promotional Videos for Two Northwestern Centers

The video production team has had a very busy spring. It began with our own version of March Madness – creating...
Read More

TEACHx’19 – Ruha Benjamin, SingerSavvyApp, and Arabic Manuscripts

The Academic Software Development team presented two digital poster sessions at the TEACHx’19 conference this week. TEACHx is presented by Northwestern...
Read More

Midwest Drupal Camp Chicago 2019

Two weeks ago, the Northwestern IT S&S Academic Software Development team – Paul Eisen, Jorge Lopez, and Gerard Panganiban – attended...
Read More

Launching of Issue #155 of TriQuarterly

Our first launch of 2019! The Academic Software Development team launched the latest issue of the TriQuarterly Magazine, issue #115. Our new...
Read More

Filming with Vadim Backman

Last week, we had a great kickoff to the new year as we began production for one of our first projects...
Read More

Why Are Some Genes Researched Less Than Others?

In a new paper published this fall by PLOS Biology, Northwestern researchers looked into why only 25% of human genes have...
Read More