Systems and methods for superimposing virtual image on real-time image

A method for superimposing a virtual image on a real-time image, comprising:

• selecting a first point on the real-time image as a first landmark;
• displaying the real-time image at a first location and a first depth with a predetermined magnification;
• projecting a virtual image by respectively projecting a right light signal to a viewer's right eye and a corresponding left light signal to a viewer's left eye, the right light signal and the corresponding left light signal being perceived by the viewer to display the virtual image at a second location and a second depth;
• wherein the virtual image is a processed image of the object;
• wherein the second depth which the viewer perceives is altered according to the predetermined magnification or the first depth of the real-time image,
• wherein the second depth which the viewer perceives is modified by changing a convergence angle between light path extensions of the right light signal and the corresponding left light signal projected to the viewer's eyes based on an interpupillary distance;
• and
• wherein the virtual image superimposes on the real-time image by overlapping a corresponding first landmark on the virtual image on a first landmark on the real-time image.