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  2. Helmholtz reciprocity - Wikipedia

    en.wikipedia.org/wiki/Helmholtz_reciprocity

    For example, incoming and outgoing light can be considered as reversals of each other, [1] without affecting the bidirectional reflectance distribution function (BRDF) [2] outcome. If light was measured with a sensor and that light reflected on a material with a BRDF that obeys the Helmholtz reciprocity principle one would be able to swap the ...

  3. Optical power - Wikipedia

    en.wikipedia.org/wiki/Optical_power

    In optics, optical power (also referred to as dioptric power, refractive power, focusing power, or convergence power) is the degree to which a lens, mirror, or other optical system converges or diverges light. It is equal to the reciprocal of the focal length of the device: P = 1/f. [1] High optical power corresponds to short focal length.

  4. Optical lens design - Wikipedia

    en.wikipedia.org/wiki/Optical_lens_design

    Optical lens design is the process of designing a lens to meet a set of performance requirements and constraints, including cost and manufacturing limitations. Parameters include surface profile types (spherical, aspheric, holographic, diffractive, etc.), as well as radius of curvature, distance to the next surface, material type and optionally tilt and decenter.

  5. Etendue - Wikipedia

    en.wikipedia.org/wiki/Etendue

    A perfect optical system produces an image with the same etendue as the source. The etendue is related to the Lagrange invariant and the optical invariant, which also share the property of being constant in an ideal optical system. The radiance of an optical system is equal to the derivative of the radiant flux with respect to the etendue.

  6. Image-forming optical system - Wikipedia

    en.wikipedia.org/wiki/Image-forming_optical_system

    In optics, an image-forming optical system is a system capable of being used for imaging. The diameter of the aperture of the main objective is a common criterion for comparison among optical systems, such as large telescopes. The two traditional optical systems are mirror-systems and lens-systems .

  7. Photometry (optics) - Wikipedia

    en.wikipedia.org/wiki/Photometry_(optics)

    Photometry is a branch of optics that deals with measuring light in terms of its perceived brightness to the human eye. [1] It is concerned with quantifying the amount of light that is emitted, transmitted, or received by an object or a system.

  8. Diaphragm (optics) - Wikipedia

    en.wikipedia.org/wiki/Diaphragm_(optics)

    In optics, a diaphragm is a thin opaque structure with an opening at its center. The role of the diaphragm is to stop the passage of light, except for the light passing through the aperture . Thus it is also called a stop (an aperture stop , if it limits the brightness of light reaching the focal plane, or a field stop or flare stop for other ...

  9. Optics and vision - Wikipedia

    en.wikipedia.org/wiki/Optics_and_vision

    Vision of humans and other organisms depends on several organs such as the lens of the eye, and any vision correcting devices, which use optics to focus the image. The eyes of many animals contains a lens that focuses the light of its surroundings onto the retina of the eye. This lens is essential to producing clear images within the eye.