Paul Debevec animates a photo-real digital face

86,222 views ・ 2009-10-20

TED


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00:18
One of the biggest challenges in computer graphics
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has been being able to create a photo-real,
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digital human face.
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And one of the reasons it is so difficult is that, unlike aliens and dinosaurs,
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we look at human faces every day.
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They are very important to how we communicate with each other.
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As a result, we're tuned in to the subtlest things
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that could possibly be wrong with a computer rendering,
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in order to believe whether these things are realistic.
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And what I'm going to do in the next five minutes
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is take you through a process
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where we tried to create a reasonably photo-realistic computer-generated face,
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using some computer graphics technology we've developed,
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and also some collaborators at a company called Image Metrics.
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And we're going to try to do a photo-real face
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of an actress named Emily O'Brien, who is right there.
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And that's actually a completely computer-generated rendering of her face.
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By the end of the talk, we're going to see it move.
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The way that we did this is we tried to start with Emily herself,
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who was gracious enough to come to our laboratory
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in Marina Del Rey, and sit for a session in Light Stage 5.
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01:12
This is a face-scanning sphere, with 156 white LEDs all around
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that allow us to photograph her
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in a series of very controlled illumination conditions.
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And the lighting that we use these days looks something like this.
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We shoot all of these photographs in about three seconds.
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And we basically capture enough information
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with video projector patterns that drape over the contours of her face,
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and different principle directions of light from the light stage,
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to figure out both the coarse-scale
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and the fine-scale detail of her face.
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If we zoom in on this photograph right here,
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we can see it's a really nice photograph to have of her,
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because she is lit from absolutely everywhere at the same time
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to get a nice image of her facial texture.
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And in addition, we've actually used polarizers on all the lights --
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just like polarized sunglasses can block
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the glare off of the road,
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polarizers can block the shine off of the skin,
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so we don't get all those specular reflections to take this map.
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Now, if we turn the polarizers around just a little bit,
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we can actually bring that specular reflection
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of the skin back in,
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and you can see she looks kind of shiny and oily at this point.
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If you take the difference between these two images here,
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you can get an image lit from the entire sphere of light
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of just the shine off of Emily's skin.
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I don't think any photograph like this had ever been taken
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before we had done this.
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And this is very important light to capture,
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because this is the light that reflects off the first surface of the skin.
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It doesn't get underneath the translucent
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layers of the skin and blur out.
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And, as a result, it's a very good cue
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to the detailed shape of the skin-pore structure
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and all of the fine wrinkles that all of us have,
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the things that actually make us look like real humans.
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So, if we use information that comes off of this specular reflection,
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we can go from a traditional face scan
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that might have the gross contours of the face and the basic shape,
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and augment it with information
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that puts in all of that skin pore structure and fine wrinkles.
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And, even more importantly,
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since this is a photometric process that only takes three seconds to capture,
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we can shoot Emily
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in just part of an afternoon,
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in many different facial poses and facial expressions.
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So, here you can see her moving her eyes around, moving her mouth around.
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And these we're actually going to use to create a photo-real digital character.
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If you take a look at these scans that we have of Emily,
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you can see that the human face does an enormous amount of amazing things
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as it goes into different facial expressions.
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You can see things. Not only the face shape changes,
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but all sorts of different skin buckling and skin wrinkling occurs.
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You can see that the skin pore structure changes enormously
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from stretched skin pores
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to the regular skin texture.
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You can see the furrows in the brow and how the microstructure changes there.
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You can see muscles pulling down at flesh to bring her eyebrows down.
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Her muscles bulging in her forehead when she winces like that.
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In addition to this kind of high-resolution geometry,
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since it's all captured with cameras, we've got a great texture map to use for the face.
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And by looking at how the different color channels of the illumination,
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the red and the green and the blue,
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diffuse the light differently,
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we can come up with a way of shading the skin on the computer.
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Then, instead of looking like a plaster mannequin,
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it actually looks like it's made out of living human flesh.
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And this is what we used
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to give to the company Image Metrics
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to create a rigged, digital version of Emily.
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We're just seeing the coarse-scale geometry here.
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But they basically created a digital puppet of her,
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where you can pull on these various strings,
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and it actually moves her face in ways that are
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completely consistent with the scans that we took.
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And, in addition to the coarse-scale geometry,
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they also used all of that detail
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to create a set of what are called "displacement maps"
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that animate as well.
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These are the displacement maps here.
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And you can see those different wrinkles actually show up as she animates.
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So the next process was then to animate her.
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We actually used one of her own performances to provide the source data.
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So, by analyzing this video with computer vision techniques,
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they were able to drive the facial rig
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with the computer-generated performance.
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So what you're going to see now, after this,
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is a completely photo-real digital face.
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We can turn the volume up a little bit if that's available.
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Emily: Image Metrics is a markerless, performance-driven animation company.
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We specialize in high-quality facial animation
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for video games and films.
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Image Metrics is a markerless, performance-driven animation company.
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We specialize in high quality facial animation
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for video games and films.
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05:21
Paul Debevec: So, if we break that down into layers, here's that diffuse component
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we saw in the first slide.
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Here is the specular component animating.
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You can see all the wrinkles happening there.
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And there is the underlying wireframe mesh.
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And that is Emily herself.
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Now, where are we going with this here?
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We've gone a little bit beyond Light Stage 5. This is Light Stage 6,
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and we're looking at taking this technology
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and applying it to whole human bodies.
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This is Bruce Lawmen, one of our researchers in the group,
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who graciously agreed to get captured running in the Light Stage.
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And let's take a look at a computer-generated version
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of Bruce, running in a new environment.
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06:01
And thank you very much.
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06:03
(Applause)
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