The XYZ->CIELAB conversion (taken from CIE 15.2 1986, “Colorimetry”) bounds L* to the range of 0-100 as follows: That is, at no point can the reflection spectrum exceed the intensity (which shows up as the L* value in CIELAB) of the reference illuminant. Thus, the resulting X, Y, and Z values (which are the starting point for other color spaces such as CIELAB) are all relative to this normalized reference illuminant. The reflection or transmission spectrum (0-100% at each wavelength) is multiplied by this illuminant before the individual color values (X, Y, Z) are computed. When doing a relative color measurement, the result is usually referenced to these illuminants: These illuminants are normalized to a value of 100 at 560 nm. I P = ( S P - D P) * C P / ( T * A * dL P)Ĭ p = Calibration file, in μJ/count (specific to the sampling optic)Ī = Collection area, in cm 2 (A=1 for an integrating sphere)ĭL P = Wavelength spread (how many nanometers each pixel represents)Ī: Typically, CIELAB is computed with some reference illuminant - e.g., A, D65, or D75. The calibration process generates a file with energy response data for each pixel in the CCD, given in μJ/count. Factoring in the surface area of the sampling optic and the integration time allows irradiance measurements in μW/cm 2 to be reported (power=energy/time). Calibration is only possible if the absolute power output of the calibration light source is known, so if the light source calibration data is not given in the units μW/cm 2/nm, it may not be a light source capable of calibrating for absolute irradiance measurements.Ĭalculating absolute irradiance takes into account the collection area of the sampling optic, and is corrected using the calibration data for each pixel, C P. Measurements in absolute irradiance mode require a calibration using a source with known power output. A spectrum is measured with the sampling optic (fiber tip, CC-3 cosine corrector, etc.) connected to the calibration light source, and is then compared to the known output power of the calibration light source. Remember to always use the light source calibration file specific to the sampling optic being used, and calibrate just prior to measurement if possible. You may also find the following Physics calculators useful.Irradiance is the measurement of radiant flux per unit area hitting or passing through a surface. An absolute irradiance measurement results in a spectrum that is accurate in both shape and magnitude. The y-axis scale becomes scaled in power or flux units like μW/nm or μW/cm 2/nm, making it easy to calculate other power or energy values. Image Formation in Plane and Curved Mirrors 12.4 - Interference and Diffraction of Light.This allows you to learn about Optics and test your knowledge of Physics by answering the test questions on Optics. At the end of each Optics tutorial you will find Optics revision questions with a hidden answer that reveals when clicked. Each Optics tutorial includes detailed Optics formula and example of how to calculate and resolve specific Optics questions and problems. The following Physics tutorials are provided within the Optics section of our Free Physics Tutorials. Optics Physics Tutorials associated with the Intensity Of Polarized Light Calculator Please provide a rating, it takes seconds and helps us to keep this resource free for all to use We believe everyone should have free access to Physics educational material, by sharing you help us reach all Physics students and those interested in Physics across the globe. This allows us to allocate future resource and keep these Physics calculators and educational material free for all to use across the globe. We hope you found the Intensity Of Polarized Light Calculator useful with your Physics revision, if you did, we kindly request that you rate this Physics calculator and, if you have time, share to your favourite social network. You can then email or print this intensity of polarized light calculation as required for later use. As you enter the specific factors of each intensity of polarized light calculation, the Intensity Of Polarized Light Calculator will automatically calculate the results and update the Physics formula elements with each element of the intensity of polarized light calculation. Please note that the formula for each calculation along with detailed calculations are available below. Intensity of the incident non-polarized light ( I 0) cd Īngle between the incident electric vector and polarizer's grid lines ( θ) ° Intensity Of Polarized Light Calculator Input Values Intensity of Polarized Light Calculator Results (detailed calculations and formula below) The Intensity of the polarized light is candela
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