Several types of supporting systems for surgical planning have been reported. This paper describes a new surgical supporting device which features image superimposition using a half-mirror. By using the device, graphic image of internal organs can be superimposed on the patient's live image. In order that the device allows users to move around, the position of the user toward the patient was measured consecutively by a small CCD camera placed on the top of a head mounted display (HMD). The CCD camera imaged a patient model with pre-arranged markers on its surface and the position of the model was measured with the accuracy of around 0.5cm by an image processing software. Based on this positional data, three dimensional model data were processed on a workstation to produce graphic image for superimposition. The image was presented to the user through the HMD which features the “see-through” function. The error in navigation by the device was found to be as large as 1cm, particularly at the peripheral view field, and this problem must be solved in the future study.
