Match Sketch(Drawing) face photo to digital color photo

Hey Guys

im going to match the sketch face (drawing photo) in to the color photo. so for the research i want to find out what are the challenges that matching sketch drawing in to color faces. for now i have find out that

1. resolution pixel difference 2. texture difference 3. distance difference 4. and color (not much effect)

i wanna know that in technical terms what are other challenges and what are available OPEN CV and JAVA CV method and algorithms to overcome that challenges????

please tell me the answers very soon hope some experts will help me thanx