Recently, due to advancements in surgical techniques and surgical equipment, surgeries for performing various treatments (also called microsurgery) while observing an affected site with an observation device for medical use, such as a surgical microscope or an endoscope, are coming to be conducted frequently. Also, such observation devices for medical use are not limited to devices that enable optical observation of the affected area, and also include devices that display an image of the affected area captured by an imaging section (camera) or the like as an electronic image on a display such as a monitor.
In addition, when displaying, on a display, an image of an affected area captured by an imaging section of an observation device, the image often is displayed as a flat two-dimensional (2D) image. However, since a sense of perspective is difficult to obtain from a 2D image, and the relative distance between the affected area and a treatment tool may be difficult to grasp, in recent years, technology that displays a captured image of an affected area as a stereoscopic three-dimensional (3D) image has also been developed. For example, Patent Literature 1 discloses an example of technology for observing a three-dimensional image.
In this way, in an observation device that displays a captured image of an affected area as a stereoscopic three-dimensional (3D) image (hereinafter designated a “stereoscopic observation device” in some cases), for example, by causing the left and right eyes to observe different viewpoint images, the user is made to observe an image of the affected area as a stereoscopic three-dimensional image.