Presentation on theme: "Introduction to Measurement Quantities Training Level: BASIC"— Presentation transcript:
1Introduction to Measurement Quantities Training Level: BASIC Dr. Richard YoungOptronic Laboratories, Inc.
2Techniques & Types of Measurement Several types of light measurement are possible. These define WHAT you measure.For each type of measurement, there are several possible techniques. These define HOW you measure.
3Techniques & Types of Measurement Techniques=howPhotometry & colorimetryRadiometrySpectroradiometryTypes=whatTotal FluxAngular IntensityAt a surfaceAt the source
4Techniques & Types of Measurement Photometry & colorimetryTypesTotal FluxAngular IntensityAt a surfaceAt the sourceHow does it look to humans?Quantities start with “photopic” or “luminous”
5Techniques & Types of Measurement RadiometryTypesTotal FluxAngular IntensityAt a surfaceAt the sourceHow much energy is produced?Quantities start with “radiometric” or “radiant”
6Techniques & Types of Measurement SpectroradiometryTypesTotal FluxAngular IntensityAt a surfaceAt the sourceHow is the energy distributed?Quantities start with “spectral” or “spectroradiometric”
7Techniques & Types of Measurement Photometry & colorimetryRadiometrySpectroradiometryTypesTotal FluxLight emitted in ALL directionsQuantities end with “flux”
8Techniques & Types of Measurement Photometry & colorimetryRadiometrySpectroradiometryTypesAngular IntensityLight emitted in SPECIFIED directions and anglesQuantities end with “intensity”
9Techniques & Types of Measurement Photometry & colorimetryRadiometrySpectroradiometryTypesAt a surfaceLight falling onto areas of an objectQuantities end with “irradiance” or “illuminance”
10Techniques & Types of Measurement Photometry & colorimetryRadiometrySpectroradiometryTypesAt the sourceLight emitted from areas within the sourceQuantities end with “radiance” or “luminance”
11Quantities and Units unit: lumen unit: Watt unit: Watt/nm Photometry + Total Flux = Total luminous fluxunit: lumenRadiometry + Total Flux = Total radiant fluxunit: WattSpectroradiometry + Total Flux = Total spectral fluxunit: Watt/nm
13Quantities and Units unit: lux = lumen/m² unit: Watt/m² Photometry + At a surface = Illuminanceunit: lux = lumen/m²Radiometry + At a surface = Irradianceunit: Watt/m²Spectroradiometry + At a surface = Spectral irradianceunit: Watt/(m² nm)
14Quantities and Units unit: candela/m² = lumen/(sr m²) Photometry + At a source = Luminanceunit: candela/m² = lumen/(sr m²)Radiometry + At a source = Radianceunit: Watt/(sr m²)Spectroradiometry + At a source = Spectral radianceunit: Watt/(sr m² nm)
15Conversion of unitsThe preceding units are SI units, currently the favored units by all National Standard Laboratories (NIST etc.)Sometimes older standards or conventions may require values to be reported in different unitsQuantities that are of the same technique and type can be converted by multiplying with a constant.
16Conversion of unitsSometimes the conversion is because the quantities use different standard unitsE.g. using inches instead of meters for measuring lengthSometimes the conversion is because the quantities use sub-unitsE.g. millimeters instead of meters
17Conversion of units Common sub-unit prefixes femto (f), multiplied by 1E-15pico (p), multiplied by 1E-12nano (n), multiplied by 1E-9micro (µ), multiplied by 1E-6milli (m), multiplied by 1E-3centi (c), multiplied by 1E-2deci (d), multiplied by 1E-1kilo (k), multiplied by 1E3mega (M), multiplied by 1E6giga (G), multiplied by 1E9tera (T), multiplied by 1E12
18Conversion to older units Conversion of unitsConversion to older unitsConvert from to multiply bycd/m²lux (lm/m²)cd/in²footlambert ((cd/ft²)/p)Lambert ((cd/cm²)/p)stilb (cd/cm²)Footcandle (lm/ft²)phot (lm/cm²)6.4516E-42.9186E-13.1416E-41.0000E-49.2903E-2