Recovering parameters from a sub-optimal image
First Claim
1. A method for processing an image containing a face, comprising:
- using a computing device to perform the following;
dividing a portion of the image containing the face into a plurality of regions;
generating an albedo morphable model for each of the plurality of regions;
using smoothness constraints to model spatial dependence between neighboring ones of the plurality of regions; and
recovering image parameters associated with the image using each of the albedo morphable models.
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Abstract
A subregion-based image parameter recovery system and method for recovering image parameters from a single image containing a face taken under sub-optimal illumination conditions. The recovered image parameters (including albedo, illumination, and face geometry) can be used to generate face images under a new lighting environment. The method includes dividing the face in the image into numerous smaller regions, generating an albedo morphable model for each region, and using a Markov Random Fields (MRF)-based framework to model the spatial dependence between neighboring regions. Different types of regions are defined, including saturated, shadow, regular, and occluded regions. Each pixel in the image is classified and assigned to a region based on intensity, and then weighted based on its classification. The method decouples the texture from the geometry and illumination models, and then generates an objective function that is iteratively solved using an energy minimization technique to recover the image parameters.
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Citations
20 Claims
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1. A method for processing an image containing a face, comprising:
using a computing device to perform the following; dividing a portion of the image containing the face into a plurality of regions; generating an albedo morphable model for each of the plurality of regions; using smoothness constraints to model spatial dependence between neighboring ones of the plurality of regions; and recovering image parameters associated with the image using each of the albedo morphable models. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A computer-readable storage medium having computer-executable instructions stored thereon for changing an illumination condition of an image containing a face, comprising:
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inputting the image that was taken under harsh lighting conditions and identifying a portion of the image containing the face as a face image; segmenting the face image into a plurality of regions; generating an albedo morphable model for each of the plurality of regions; holding an illumination constant and solving for albedo and geometry in an iterative manner; generating a geometry morphable model for each of the plurality of regions such that the geometry morphable model and the albedo morphable model are two separate morphable models; and holding the albedo and geometry constant and solving for illumination in an iterative manner. - View Dependent Claims (12, 13, 14, 15)
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16. A computer-implemented process for improving an illumination of a single image containing a face and taken under sub-optimal illumination conditions, comprising:
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computing an initial shape estimation of the face to generate a face image, wherein the face image is the portion of the image containing the face; classifying each pixel in the face image as one of;
(a) a saturated pixel;
(b) a shadow pixel;
(c) a regular pixel;
(d) an occluded pixel;weighting each pixel in the face image based on its classification; assigning each pixel to one of a plurality of regions in the face image based on the pixel classification; generating using the computer an albedo morphable model for each of the plurality of regions; generating using the computer a geometry morphable model for each of the plurality of regions such that the geometry morphable model and the albedo morphable model are two separate morphable models; and obtaining image parameters from the morphable models that are used to improve the illumination of the single image containing the face. - View Dependent Claims (17, 18, 19, 20)
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Specification