Edge-Based Automated Facial Blemish Removal

Abstract

This thesis presents an end-to-end approach for taking a an image of a face and seamlessly isolating and filling in any blemishes contained therein. This consists of detecting the face within a larger image, building an accurate mask of the facial features so as not to mistake them as blemishes, detecting the blemishes themselves and painting over them with accurate skin tones.

We devote the first part of the thesis to detailing our algorithm for extracting facial features. This is done by first improving the image through histogram equal- ization and illumination compensation followed by finding the features themselves from a computed edge map. Geometric knowledge of general feature positioning and blemish shapes is used to determine which edge clusters belong to correspond- ing facial features. Color and reflectance thresholding is then used to build a skin map.

In the second part of the thesis we identify the blemishes themselves. A Lapla- cian of Gaussian blob detector is used to identify potential candidates. Thresholding

and dilating operations are then performed to trim this candidate list down followed by the use of various morphological properties to reject regions likely to not be blem- ishes.

Finally, in the third part, we examine four possible techniques for inpainting blemish regions once found. We settle on using a technique that fills in pixels based on finding a patch in the nearby image region with the most similar surrounding texture to the target pixel. Priority in the pixel fill-order is given to strong edges and contours.