Real vs Virtual Image
A real image is formed where rays of light actually converge and can be projected on a screen. Inverted, on the opposite side of a converging lens or in front of a concave mirror. Examples: image on a camera sensor, slide projected on a wall, retinal image inside the eye.
A virtual image is the apparent location from which diverging rays seem to originate after refraction or reflection. Cannot be projected on a screen. Upright, on the same side as the object. Examples: image in a flat mirror, magnified image in a magnifying glass (object closer than f), image in a diverging lens.
Sign convention: real image distance s′ > 0; virtual image distance s′ < 0 (in the Cartesian convention used in most textbooks).
Recent research on this topic from arXiv
Preprints and papers indexed on arXiv.org. Links open the public abstract pages.
- Wave optics and image formation in gravitational lensing
Yasusada Nambu · 2012 ·arXiv:1207.6846v1
We discuss image formation in gravitational lensing systems using wave optics. Applying the Fresnel-Kirchhoff diffraction formula to waves scattered by a gravitational potential of a lens object, we demonstrate how images of source objects... - Exploiting nonlinear incoherent image formation through linear volume metaoptics for inference
Nan Zhang, Arvin Keshvari, Ata Shakeri et al. · 2025 ·arXiv:2508.19436v1
We showed that a 2D depth map representing an incoherent 3D opaque scene is directly encoded in the response function of an imaging optics. As a result, the optics creates an image that depends nonlinearly on the depth map. Furthermore, str... - Nonlinear Image Formation by Optical Superlattices
Bo Yang, Xu-Hao Hong, Rong-Er Lu et al. · 2015 ·arXiv:1511.07121v1
The angular spectrum theory is applied to the nonlinear harmonic generation process in optical superlattices. Several explicit and analytical structure functions are deduced to design optical superlattices for various purposes. Employing th... - Nonlocal Optical Real Image Formation Theory
Greyson Gilson · 2010 ·arXiv:1012.4085v5
A nonlocal theory of optical real image formation is developed from the basic quantum physics linked to an optical real image formation apparatus. Optical real images are formed by photons. Photons are nonlocal quantum objects that exhibit...
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