In
optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...
, an erect image is one that appears right-side up. An
image
An image is a visual representation of something. It can be two-dimensional, three-dimensional, or somehow otherwise feed into the visual system to convey information. An image can be an artifact, such as a photograph or other two-dimensiona ...
is formed when
rays
Ray may refer to:
Fish
* Ray (fish), any cartilaginous fish of the superorder Batoidea
* Ray (fish fin anatomy), a bony or horny spine on a fin
Science and mathematics
* Ray (geometry), half of a line proceeding from an initial point
* Ray (gra ...
from a point on the original object meet again after passing through an optical system. In an erect image, directions are the same as those in the object, in contrast to an inverted image. It is one of the properties of images formed in a
plane mirror.
Some
telescopes
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe ...
and other devices such as the
camera obscura
A camera obscura (; ) is a darkened room with a aperture, small hole or lens at one side through which an image is 3D projection, projected onto a wall or table opposite the hole.
''Camera obscura'' can also refer to analogous constructions su ...
present an inverted image on the viewing surface.
Mirror
A mirror or looking glass is an object that Reflection (physics), reflects an image. Light that bounces off a mirror will show an image of whatever is in front of it, when focused through the lens of the eye or a camera. Mirrors reverse the ...
s and
compound prism
A compound prism is a set of multiple triangular prism, triangular prism elements placed in contact, and often cemented together to form a solid assembly. The use of multiple elements gives several advantages to an optical designer:Nathan Hagen and ...
elements can be used to achieve an erect image instead.
Optics
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