Face Swapping: Automatically Replacing Faces in Photographs |
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Advances in digital photography have made it possible to capture
large collections of high-resolution images and share them
on the internet. While the size and availability of these collections
is leading to many exciting new applications, it is
also creating new problems. One of the most important of
these problems is privacy. Online systems such as Google
Street View allow users to interactively
navigate through panoramic images of public places created using
thousands of photographs. We believe
that an attractive solution to the privacy problem is to remove the
identities of people in photographs by automatically replacing their
faces with ones from a collection of stock images. Automatic face replacement has other compelling applications as
well. For example, people commonly have large personal collections
of photos on their computers. These collections often contain
many photos of the same person(s) taken with different expressions,
and under various poses and lighting conditions. One can use such
collections to create novel images by replacing faces in one image
with more appealing faces of the same person from other images.
For group shots, the burst mode available in most cameras can
be used to take several images at a time. With an automatic face
replacement approach, one could create a single composite image
with, for example, everyone smiling and with both eyes open.
In this project, we present a complete system for automatic face replacement
in images. Our system uses a large library of face images
created automatically by downloading images from the internet, extracting
faces using face detection software, and aligning each extracted
face to a common coordinate system. This library is constructed
off-line, once, and can be efficiently accessed during face
replacement. Our replacement algorithm has three main stages.
First, given an input image, we detect all faces that are present,
align them to the coordinate system used by our face library, and
select candidate face images from our face library that are similar
to the input face in appearance and pose. Second, we adjust the
pose, lighting, and color of the candidate face images to match the
appearance of those in the input image, and seamlessly blend in
the results. Third, we rank the blended candidate replacements by
computing a match distance over the overlap region. Our approach
requires no 3D model, is fully automatic, and generates highly plausible
results across a wide range of skin tones, lighting conditions,
and viewpoints. We show how our approach can be used for a variety
of applications including face de-identification and the creation
of appealing group photographs from a set of images. |
Publications
"Face Swapping: Automatically Replacing Faces in Photographs," D. Bitouk, N. Kumar, S. Dhillon, P. Belhumeur, S. K. Nayar, ACM Trans. on Graphics (also Proc. of ACM SIGGRAPH), Aug, 2008. [PDF] [bib] [©]
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Pictures
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Color and Lighting Adjustment:
In this example, we demonstrate the importance of our color and lighting adjustment algorithm. We replace (a) the face in the input photograph with (b) the face selected from the library.
Replacement results (c) without and (d) with recoloring and relighting.
Notice the significantly improved realism in the final result.
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Face Replacement Results:
Here, we show several examples of the results obtained using our
system. Each example shows, in order from left to right, the input
face image, a candidate face, and the replacement result. Note
the realism of the results, despite differences in pose, lighting and
facial appearance.
Each row contains (from left to right) the original photograph, a candidate face selected from the
library, and the replacement result produced automatically using
our algorithm. The age and gender mismatches in (c) and (d) could
be avoided by enforcing consistency across those attributes (which
our system does not currently do).
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Face De-Identification:
To preserve privacy in online collections
of photos, one can use our system to automatically replace each
face in an input image with the top-ranked candidate taken from a
collection of stock photographs. We show the result of automatically
replacing the input faces (top) with the top-ranked candidate
from the face library to obtain the de-identified results (bottom).
No user intervention was used to produce this result.
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Face Switching:
As a special case of face de-identification (or for use as a special effect), we can limit the system to use candidates only within the same image, resulting in the switching of faces.
Here, we show the result of switching Elvis Presley and Richard Nixon’s faces (left) with each other to obtain the de-identified output (right).
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Burst Mode Replacement:
When taking group photographs, it is often difficult to get a “perfect” picture – where, for
example, everyone is smiling, with eyes open, and looking at the
camera. From a set of images taken using the “burst” mode of a camera (left panel), a composite image is
created in which everyone is smiling and has their eyes open (right panel). The candidate faces for each child are constrained by the relative positions of the faces in all images, and thus no face recognition is required. While in this case the best replacement face for each child was selected manually (outlined in blue), blink and smile detection could be applied to select them automatically.
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Limitations:
Here, we show several examples of limitations of our algorithm itself.Input and replacement candidate faces are
shown on the top, replacement results in the middle, and a detailed
inset of the problem area on the bottom. The lack of eyeglasses in
(a) and the occluding finger in (b) cause visual artifacts in the results.
In (c), the extreme pose of the face results in it being blended
into the background. These problems could be solved by dynamically
selecting optimal replacement regions. (d) shows a relighting
failure case, caused by forcing a replacement between images with
very different lighting (skipping our lighting selection step).
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Videos
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SIGGRAPH 2008 Video:
This video introduces the complete system for automatic face replacement
in images, summarizes the face replacement algorithm, and demonstrates several applications of our method, including face de-identification, personalized face replacement, and the creation
of appealing group photographs from a set of images. (With narration)
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Related Projects
Speech-Enabled Avatars
Optimal Illumination for Video Relighting
Appearance Matching
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