These are the three attributes of color.
Brightness is the achromatic component, i.e., light power or intensity that detected by our eye.
Hue and saturation are the chromatic components. Simply defining,
Hue = wavelength;
Saturation = spectral purity.
Hue:
The wavelength that appears most prevalent in a color sample determines its hue. The set of basic hues, for example, 赤橙黄绿青蓝紫, is very subjective and differ from culture to culture.
Saturation:
"Spectral purity" is enough to define saturation. Lasers produce the most saturated colors whereas white-gray-black are the least saturated colors.
References:
1. Bruce Fraser, Chris Murphy, and Fred Bunting, Real World Color Management, 2nd ed. Peachpit Press 2005
Showing posts with label Brightness. Show all posts
Showing posts with label Brightness. Show all posts
Sunday, April 12, 2009
Monday, April 21, 2008
Laser Beam Quality Parameters
Some parameters related to laser beam quality are given here.
1. M-square factor
This is the most widely used parameter.
The capital letters Wo and Θ are beam waist radius and half-width divergence respectively for a general multimode Gaussian beam (I use lower-case wo and θ for the "imbedded" fundamental Gaussian beam [1]).
2. Beam parameter product (BPP) [2]
This parameter is defined as the product of beam width and full beam divergence:
3. Brightness
Brightness is essentially equivalent to radiance [3], i.e., power in a unit cross-sectional area and a unit solid angle:
References:
[1] T.F. Johnston, "Beam propagation (M2) measurement made as easy as it gets: the four-cuts method", Appl. Opt. 37, 4840 (1998).
[2] X. Gao et al., "Beam-shaping technique for improving the beam quality of a high-power laser-diode stack", Opt. Lett. 31, 1654 (2006).
[3] http://www.rp-photonics.com/brightness.html
1. M-square factor
This is the most widely used parameter.
| M2 = | πWoΘ λ | (1) |
The capital letters Wo and Θ are beam waist radius and half-width divergence respectively for a general multimode Gaussian beam (I use lower-case wo and θ for the "imbedded" fundamental Gaussian beam [1]).
2. Beam parameter product (BPP) [2]
This parameter is defined as the product of beam width and full beam divergence:
| BPP=2W0*2Θ=4M2λ/π | (2) |
3. Brightness
Brightness is essentially equivalent to radiance [3], i.e., power in a unit cross-sectional area and a unit solid angle:
| B = | P πW02πΘ2 | = | P (M2)2λ2 | (3) |
References:
[1] T.F. Johnston, "Beam propagation (M2) measurement made as easy as it gets: the four-cuts method", Appl. Opt. 37, 4840 (1998).
[2] X. Gao et al., "Beam-shaping technique for improving the beam quality of a high-power laser-diode stack", Opt. Lett. 31, 1654 (2006).
[3] http://www.rp-photonics.com/brightness.html
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