Evaluation of performances of musical instruments is usually subjective. It may be easier for keyboard instruments. For bowed-string instruments such as a violin, delicate articulations are required in its performance such that there exhibit much complexities in its sound, making the evaluation more difficult. In this paper, a note separation algorithm based on spectral domain factorization is used to extract the notes from recordings of violin solo performances. Each note can then be quantitatively evaluated based on a set of metrics that is designed to provide various aspects of violin performances including pitch accuracy, bowing steadiness, vibrato depth/rate, bowing intensity, tempo, and timbre characteristics and so on. The tools should be useful in musical instrument performance education.