Which device served as an early 3D viewing mechanism?

• A. Stereopticon
• B. Stereoscope
• C. Anaglyph Glasses
• D. Polarized Projector

Answer: (A)

Early 3D viewing relies on delivering two slightly different images to each eye so the brain can fuse them into a sense of depth. The Stereopticon fits this idea because it is a projection device that presents paired images through a special optical setup for audiences, allowing a viewer to perceive depth on a screen in a viewing session. This projection-based approach contrasts with the stereoscope, which is a personal, handheld viewer that lets a single person look at two images side by side to fuse depth in their own eyes, rather than projecting a 3D effect to a room. The other options involve methods that came later or rely on different principles: Anaglyph glasses wearers use color-filtered images to separate the views, and polarized projection requires glasses to separate polarized light in a cinema setting.