“I got really lucky and the project I’m doing here is basically applying my thesis work to 3D printing,” says HP Labs summer intern Michael Ludwig, who uses computer graphics to study the simulation of materials and their appearances and applies those insights to understanding how humans see complex materials. Ludwig has almost completed his Ph.D. in computer science at the University of Minnesota, from which he also holds a BS in computer science. When not working, he likes to bike, train his dog and write his own computer graphics programs.
HP: Tell us more about the work you are doing at HP Labs.
I study how people see things and how we can model that computationally. When you are thinking about reproducing the appearance of things in 2D, it’s mostly about color and the texture of the paper you are printing on. But with 3D printing, you have to think about color in three dimensions and also surface curvature and geometry, and then the qualities of the different kinds of materials that you are printing to. So when you want to make something look like it does on your monitor, there are lots of ways in which the two might not match. I’m trying to come up with a quantifiable metric for measuring how much they match or not.
HP: What’s the value in doing that?
Right now, when it comes to printing things in 3D you will have errors or defects that may or may not be visible. But the way we measure that accuracy is mostly by eyeballing it and saying, “I think that’s better (or not) than we have done it before.” What I’m doing is trying to put some numbers to that process that line up with the way people see things. Then we can potentially use that as our guide for how “well” something is printed.
HP: How are you going about creating that metric?
I’m starting with a user study that will collect data about how people see these types of defects in 3D printed objects. Then I’m going to apply a hypothesis from my thesis to see if it fits end models of the data that we collected.
HP: Do you have any results yet?
It’s a bit early for that. I’m still learning about all potential problems that come up in 3D printing. After that, I’ll establish what we’ll ask our human subjects to do and how we’ll accurately measure what they’re seeing, and then figure out how we take that data to establish the metric I’m looking to create.
HP: Will this feed back into your Ph.D. research?
Yes. Back in Minnesota, I’m working on applying the same model to a broader psycho-physical question, looking at variations in appearances across different areas and asking whether it’s possible to create a framework for a general appearance metric. So this work on 3D appearance metrics gives me another instance that will help me figure that out. But even if it only works for 3D printing, it would be a very useful tool for people in that specific field to have.
HP: What other fields could appearance metrics be useful for?
Automotive technology is a big one, where understanding appearance impacts computer vision for assisted or automated driving technologies and also helps give people a realistic idea of how different paints and finishes would change the look of a car. But really it has use in any industrial design or quality control process where designers work with manufacturers to create a specific visual impact.
HP: How has working at HP Labs changed your perspective on the challenge you are addressing?
It’s been really valuable to see a design-to-manufacture process up close. There are also some very advanced tools here – like one that scans materials and creates a virtual representation of them – that I can see would be able to use metrics like the one I’m trying to come up with.
HP: What have you liked so far about working at HP Labs?
I’ve only had one internship before, which was at Google, and I’ve enjoyed the fact that HP Labs feels much more “scientific.” It’s been really cool to come in to work and have a fully-equipped chemistry lab ten feet from my desk that I can potentially interact with. It’s also been really validating to share my ideas with people here and have them respond so positively.