1. A method of visualizing occlusions in an image comprising the steps of: providing a server computer including a graphics processing unit and a first memory, where the server computer: a) receives a 3-D volumetric image reconstructed from a plurality of measured 2-D projection images; b) computes three or more generated 2-D projection images based on three or more 3-D volumetric image viewing directions, where a first viewing direction generated by a first straight line drawn between a first position and an object is used to compute a first generated 2-D projection image, where the angle between the first straight line and the first viewing direction is given by θ0, where θ0 is equal to zero, a second viewing direction generated by a second straight line drawn between a second position and the object is used to compute a second generated 2-D projection image, where the angle between the second straight line and the first viewing direction is given by θ1, and at least a third viewing direction generated by a third straight line drawn between a third position and the object is used to compute a third generated 2-D projection image, where the angle between the third straight line and the first viewing direction is θ2; c) sends the three or more generated 2-D projection images and viewing instructions to a remote device which includes a graphics display unit and a second memory, where the three or more generated 2-D projection images are stored in the second memory; and d) displays the three or more generated 2-D projection images to enhance visualizations of occlusions, where the viewing instructions determine that the three or more generated 2-D projection images are displayed on the graphics display unit in time delay corresponding with one or both increasing and decreasing θ.