The invention relates to a visualization apparatus for visualizing a quality of applying energy to an object. The quality of applying energy at a location on the object (3) is visualized based on a) a provided image of the object and b) a provided quality value which is a depth value indicative of the depth to which the applied energy has altered the object, representing the quality of applying energy to the object at the location on the object (3), wherein a visual property assigning unit (9) assigns a visual property to the location depending on the quality value and a display (10) displays the provided image and the assigned visual property at the location on the object shown in the image as a transmural region calculated using depth value(s) with respect to a wall of the object. In general a person who applies energy to the object is focused on the location at which energy is applied. Since quality information is shown at the location on which the person is already focused, the quality dependent information can easily be absorbed by the person.
