Search results
Results From The WOW.Com Content Network
Comparison of photometric and radiometric quantities. Radiometry is a set of techniques for measuring electromagnetic radiation, including visible light.Radiometric techniques in optics characterize the distribution of the radiation's power in space, as opposed to photometric techniques, which characterize the light's interaction with the human eye.
Luminous intensity (photometric) and radiant intensity (radiometric) In photometric quantities every wavelength is weighted according to how sensitive the human eye is to it, while radiometric quantities use unweighted absolute power. For example, the eye responds much more strongly to green light than to red, so a green source will have ...
cd/m 2 (= lm/(sr⋅m 2)) L −2 ⋅J: Luminous flux per unit solid angle per unit projected source area. The candela per square metre is sometimes called the nit. Illuminance: E v: lux (= lumen per square metre) lx (= lm/m 2) L −2 ⋅J: Luminous flux incident on a surface Luminous exitance, luminous emittance M v: lumen per square metre lm/m ...
Luminous intensity, a photometric quantity measured in lumens per steradian (lm/sr), or candela (cd) Irradiance, a radiometric quantity, measured in watts per square meter (W/m 2) Intensity (physics), the name for irradiance used in other branches of physics (W/m 2) Radiance, commonly called "intensity" in astronomy and astrophysics (W·sr −1 ...
For each photometric system a set of primary standard stars is provided. A commonly adopted standardized photometric system is the Johnson-Morgan or UBV photometric system (1953). At present, there are more than 200 photometric systems. [citation needed] Photometric systems are usually characterized according to the widths of their passbands:
2 = any non-empty string other than "self" The template will display a "(Compare)" link (as above). However, the link will point to the corresponding photometry table in the separate article on " Photometry (optics) ", not to within the article, where the {{SI radiometry units}} template has been included.
Radiosity of a surface, denoted J e ("e" for "energetic", to avoid confusion with photometric quantities), is defined as [3] = =, +, +,, where ∂ is the partial derivative symbol; is the radiant flux leaving (emitted, reflected and transmitted)
The Field of view of a lens is limited by the size of the image plane and the focal length of the lens. The relationship between a location on the image and a location on the object is y = f*tan(θ), where y is the max extent of the image plane, f is the focal length of the lens and θ is the field of view.