The paper addresses the problem of interactive facial feature localization from a single image, aiming to achieve accurate segmentation of facial features under various conditions such as pose, expression, and lighting. The authors propose an improvement to the Active Shape Model (ASM) that allows greater independence among facial components and introduces a Viterbi optimization process for appearance fitting along facial contours. They also develop an interaction model that enables users to guide the algorithm towards precise solutions. To validate their approach, the authors introduce the Helen Facial Feature Dataset, which consists of 2330 high-resolution, annotated portrait images. The dataset is more diverse and challenging than existing datasets. Experiments show that their automatic method outperforms state-of-the-art systems, and the interactive method significantly reduces errors with minimal user interaction. The paper includes a detailed description of the component-based ASM model, the profile model, and the interactive refinement algorithm, along with comparisons to existing methods and evaluations of user interaction effectiveness.The paper addresses the problem of interactive facial feature localization from a single image, aiming to achieve accurate segmentation of facial features under various conditions such as pose, expression, and lighting. The authors propose an improvement to the Active Shape Model (ASM) that allows greater independence among facial components and introduces a Viterbi optimization process for appearance fitting along facial contours. They also develop an interaction model that enables users to guide the algorithm towards precise solutions. To validate their approach, the authors introduce the Helen Facial Feature Dataset, which consists of 2330 high-resolution, annotated portrait images. The dataset is more diverse and challenging than existing datasets. Experiments show that their automatic method outperforms state-of-the-art systems, and the interactive method significantly reduces errors with minimal user interaction. The paper includes a detailed description of the component-based ASM model, the profile model, and the interactive refinement algorithm, along with comparisons to existing methods and evaluations of user interaction effectiveness.