1. A method for guiding a user in performing a Cardio-Pulmonary Resuscitation procedure on a patient involving a portable device comprising a camera, and a display, the method comprising a) receiving data representing a video of the patient captured by the camera, b) processing the video to segment a chest region of the patient, c) determining a target position on the chest region where to position hands for performing Cardio-Pulmonary Resuscitation, and d) visualizing the target position on the chest region by displaying the video of the patient overlaid with an image of the determined target position on the display so as to guide the user in obtaining a suitable hand position for performing the Cardio-Pulmonary Resuscitation procedure, wherein the overlaying further comprises graphics symbols of two arms, wherein the graphics symbols of two arms are animated to guide the user in obtaining a correct hand position for performing the Cardio-Pulmonary Resuscitation procedure.