Patent ID: 7039216

Claim:
A computer-implemented process for generating a sketch of a person's face from an image of the person's face, comprising: a training step comprising, an inputting step for inputting a set of training images each of which depicts a person's face, a drawing step for drawing a set of training sketches each representing a respective face depicted in the training images, an identifying step for identifying a prescribed set of points in each training image, said points marking the contours of a prescribed set of facial features, a teaching step for teaching an active shape model module using the identified feature points to automatically locate said prescribed set of points in an arbitrary image of a person's face, a computing step for computing a meanshape vector by forming a separate shape vector for each training image from the identified feature points of that image and averaging the corresponding elements of each shape vector, wherein each shape vector has identically ordered elements, a defining step for defining a geometric transform function for each training image which warps that image so that the identified feature points in vectorized form equals the meanshape vector, a warping step for warping each training image and its corresponding sketch using the geometric transform function associated with the training image to create transformed versions thereof, and a second defining step for defining a sketch model comprising a set of lines representative of the lines found in the transformed training sketches; and a sketch generating step comprising, a second inputting step for inputting an image of a person's face, an employing step for employing the active shape model to locate said prescribed set of facial feature points in the input image, a third defining step for defining a geometric transform function for the input image which warps the input image so the located feature points thereof in vectorized form equals the meanshape vector, a second warping step for warping the input image using the geometric transform function associated with the input image to create a transformed input image, a creating step for employing a non-parametric sampling module to create an expected sketch image from the transformed input image as well as the transformed training images and sketches, a fitting step for fitting the lines defined in the sketch model to the expected sketch image to create a transformed input image sketch comprising those lines of the sketch model that correspond to facial features found in the expected sketch image, and an applying step for applying an inverse of the input image geometric transform function to the transformed input image sketch to unwarp the sketch such that the shape and location of the lines making up the sketch match the shape and location of corresponding facial features in the input image.