Placeholder Image

Subtitles section Play video

  • One of the biggest challenges in computer graphics

  • has been being able to create a photo-real,

  • digital human face.

  • And one of the reasons it is so difficult is that, unlike aliens and dinosaurs,

  • we look at human faces every day.

  • They are very important to how we communicate with each other.

  • As a result, we're tuned in to the subtlest things

  • that could possibly be wrong with a computer rendering,

  • in order to believe whether these things are realistic.

  • And what I'm going to do in the next five minutes

  • is take you through a process

  • where we tried to create a reasonably photo-realistic computer-generated face,

  • using some computer graphics technology we've developed,

  • and also some collaborators at a company called Image Metrics.

  • And we're going to try to do a photo-real face

  • of an actress named Emily O'Brien, who is right there.

  • And that's actually a completely computer-generated rendering of her face.

  • By the end of the talk, we're going to see it move.

  • The way that we did this is we tried to start with Emily herself,

  • who was gracious enough to come to our laboratory

  • in Marina Del Rey, and sit for a session in Light Stage 5.

  • This is a face-scanning sphere, with 156 white LEDs all around

  • that allow us to photograph her

  • in a series of very controlled illumination conditions.

  • And the lighting that we use these days looks something like this.

  • We shoot all of these photographs in about three seconds.

  • And we basically capture enough information

  • with video projector patterns that drape over the contours of her face,

  • and different principle directions of light from the light stage,

  • to figure out both the coarse-scale

  • and the fine-scale detail of her face.

  • If we zoom in on this photograph right here,

  • we can see it's a really nice photograph to have of her,

  • because she is lit from absolutely everywhere at the same time

  • to get a nice image of her facial texture.

  • And in addition, we've actually used polarizers on all the lights --

  • just like polarized sunglasses can block

  • the glare off of the road,

  • polarizers can block the shine off of the skin,

  • so we don't get all those specular reflections to take this map.

  • Now, if we turn the polarizers around just a little bit,

  • we can actually bring that specular reflection

  • of the skin back in,

  • and you can see she looks kind of shiny and oily at this point.

  • If you take the difference between these two images here,

  • you can get an image lit from the entire sphere of light

  • of just the shine off of Emily's skin.

  • I don't think any photograph like this had ever been taken

  • before we had done this.

  • And this is very important light to capture,

  • because this is the light that reflects off the first surface of the skin.

  • It doesn't get underneath the translucent

  • layers of the skin and blur out.

  • And, as a result, it's a very good cue

  • to the detailed shape of the skin-pore structure

  • and all of the fine wrinkles that all of us have,

  • the things that actually make us look like real humans.

  • So, if we use information that comes off of this specular reflection,

  • we can go from a traditional face scan

  • that might have the gross contours of the face and the basic shape,

  • and augment it with information

  • that puts in all of that skin pore structure and fine wrinkles.

  • And, even more importantly,

  • since this is a photometric process that only takes three seconds to capture,

  • we can shoot Emily

  • in just part of an afternoon,

  • in many different facial poses and facial expressions.

  • So, here you can see her moving her eyes around, moving her mouth around.

  • And these we're actually going to use to create a photo-real digital character.

  • If you take a look at these scans that we have of Emily,

  • you can see that the human face does an enormous amount of amazing things

  • as it goes into different facial expressions.

  • You can see things. Not only the face shape changes,

  • but all sorts of different skin buckling and skin wrinkling occurs.

  • You can see that the skin pore structure changes enormously

  • from stretched skin pores

  • to the regular skin texture.

  • You can see the furrows in the brow and how the microstructure changes there.

  • You can see muscles pulling down at flesh to bring her eyebrows down.

  • Her muscles bulging in her forehead when she winces like that.

  • In addition to this kind of high-resolution geometry,

  • since it's all captured with cameras, we've got a great texture map to use for the face.

  • And by looking at how the different color channels of the illumination,

  • the red and the green and the blue,

  • diffuse the light differently,

  • we can come up with a way of shading the skin on the computer.

  • Then, instead of looking like a plaster mannequin,

  • it actually looks like it's made out of living human flesh.

  • And this is what we used

  • to give to the company Image Metrics

  • to create a rigged, digital version of Emily.

  • We're just seeing the coarse-scale geometry here.

  • But they basically created a digital puppet of her,

  • where you can pull on these various strings,

  • and it actually moves her face in ways that are

  • completely consistent with the scans that we took.

  • And, in addition to the coarse-scale geometry,

  • they also used all of that detail

  • to create a set of what are called "displacement maps"

  • that animate as well.

  • These are the displacement maps here.

  • And you can see those different wrinkles actually show up as she animates.

  • So the next process was then to animate her.

  • We actually used one of her own performances to provide the source data.

  • So, by analyzing this video with computer vision techniques,

  • they were able to drive the facial rig

  • with the computer-generated performance.

  • So what you're going to see now, after this,

  • is a completely photo-real digital face.

  • We can turn the volume up a little bit if that's available.

  • Emily: Image Metrics is a markerless, performance-driven animation company.

  • We specialize in high-quality facial animation

  • for video games and films.

  • Image Metrics is a markerless, performance-driven animation company.

  • We specialize in high quality facial animation

  • for video games and films.

  • Paul Debevec: So, if we break that down into layers, here's that diffuse component

  • we saw in the first slide.

  • Here is the specular component animating.

  • You can see all the wrinkles happening there.

  • And there is the underlying wireframe mesh.

  • And that is Emily herself.

  • Now, where are we going with this here?

  • We've gone a little bit beyond Light Stage 5. This is Light Stage 6,

  • and we're looking at taking this technology

  • and applying it to whole human bodies.

  • This is Bruce Lawmen, one of our researchers in the group,

  • who graciously agreed to get captured running in the Light Stage.

  • And let's take a look at a computer-generated version

  • of Bruce, running in a new environment.

  • And thank you very much.

  • (Applause)

One of the biggest challenges in computer graphics

Subtitles and vocabulary

Click the word to look it up Click the word to find further inforamtion about it