Question

How can you tell that a hologram is a true three-dimensional image and that those in 3-D movies are not?

a) Holograms use a single perspective; 3-D movies use multiple perspectives.

b) Holograms exhibit parallax; 3-D movies lack parallax.

c) 3-D movies use lasers; holograms use diffraction patterns.

d) Holograms are projected on screens; 3-D movies are projected in space.

Answer 1

A hologram is a true three-dimensional image because it exhibits parallax, which means that objects in the hologram change relative position as viewers move, simulating real-world perspective changes. In contrast, 3-D movies project two static images to create a stereoscopic effect but lack the dynamic perspective change, hence they do not have true parallax. The mentioned correct option in the final part of the answer is option b) Holograms exhibit parallax; 3-D movies lack parallax.

Step-by-step explanation:

To determine whether a hologram is a true three-dimensional image and why those in 3-D movies are not, it is important to understand how each technology presents visual information. A hologram is a photographic recording of a light field, which uses laser light to capture the image. Unlike traditional photographs, a hologram contains the depth information of the objects, as it records both the intensity and the phase of the light waves hitting the film. When such a hologram is illuminated by the same type of laser light used to create it, the diffraction patterns on the film recreate the light field of the original scene. This phenomenon allows viewers to experience a true 3D image; as viewers move, objects in the hologram appear to change relative position, simulating real-world parallax.

In contrast, 3-D movies utilize a completely different technique to give the illusion of depth. They employ two slightly different images or perspectives, one for each eye, to create a stereoscopic effect. However, these images are static and do not change perspective as a viewer moves his or her head. Therefore, there is no parallax in 3-D movies, which is the effect that allows our eyes to perceive depth as we move around. The correct option in answering how you can tell that a hologram is a true three-dimensional image is option b): Holograms exhibit parallax; 3-D movies lack parallax. This difference in how images are presented and the user's interaction with them is what distinguishes the true 3D nature of holograms from the simulated 3D effect of movies.