Colorimetric practice

Colour measuring instrumentsLightsource colorimetryLuminance and brightness descriptionMeasurement of materials: colour recipe,

fluorescence, signal colours

Instruments

Tristimulus colorimeters

Spectroradiometers

scanning, band-width and sampling

CCD type, missed details

Image forming colorimeters

Tristimulus colorimeter

Luminace and illuminance measuring

Tristimulus filters

Sandwich type filtersPartial filtering

Goodness of fit evaluation

Spectral mismatch error description

fs t

t

i

i

10

0

100'*

%

() ()d

()d

rel

rel

0

relm

0

m

rel )(

d)()(

d)()(

)(*

s

sS

tS

si

Spectral match of a full-filtered instrument

0.0000

0.2000

0.4000

0.6000

0.8000

1.0000

1.2000

1.4000

1.6000

1.8000

400 450 500 550 600 650 700 750

wavelength, nm

rel.

resp

.

x(Si)

y(Si)

z(Si)

x(CIE)

y(CIE)

z(CIE)

F1x=2.6, F1y=2.2, f1z=3.8

Angular responsivity

Illuminace type: cosine corrected

Luminance type: narrow beam measurement: 0.5 ° … 2°opening angle

Image forming colorimeter problem with contrast, induction and

assimilation

Colour correction of a CCD colorimeter

F1x=7.5, f1y=3.6, f1z=3.9

0.0000

0.2000

0.4000

0.6000

0.8000

1.0000

1.2000

1.4000

1.6000

1.8000

400 450 500 550 600 650 700 750

wavelength, nm

rel.

resp

.

x(CCD)

y(CCD)

z(CCD)

x(CIE)

y(CIE)

z(CIE)

Spectroradiometry

Optics of the equipmentBandwidthStray lightSingle and double monochromatorsDetection

photomultipliers CCD arrays

SpectroradiometrySpectroradiometry

Spectral irradiance measurement

Spectral radiance and flux measurement

The spectroradiometerMeasurement principlesPractical measurements

The spectroradiometer The spectroradiometer systemsystem

Input optical arrangement-1Input optical arrangement-1

Input optical arrangement-2Input optical arrangement-2

Monochromators - 1

Light grasp or etendu, throughput, efficiency:

Double monochromator: Two gratings (additive, subtractive

dispersion) grating + prism

Zh A

f( )

( ).

d

d

Monochromators - 2

Stray radiationDetermination with Interference filter: Sharp cut-off filters Lasers

Wavelength accuracy: +/- 0,1 nm stability temperature dependence: 0,1 - 0,5

nm/C°

s

( )

( )

R T

R2

11

Detector and measuring Detector and measuring systemsystem

Irradiation of detector - homogeneityType of detector: photomultiplier, Si-

cell linearity (superposition) temperature dependence high voltage stability

Standard sourcesMethod of measurement

Method of measurementMethod of measurement

Sequence: test - standardTransmittance function -

Bandwidth

Bandwidth & samplingBandwidth & sampling

Continuous scan methodContinuous scan method

Grating monochromator

Second order specrum, cutting by filters or a prisn pre-disperser

k i l é p õ r é s

o p t i k a i r á c s

a n a l i z á t o r t ü k ö r

k o l l i m á t o r t ü k ö r

b e l é p õ r é s

CCD type detector systems

Single grating stray light second order

Detector system Pixel area – inter pixel area linearity dynamic range

CCD arrey spectrometerb e l é p õ r é s

C C D é r z é k e l õ

r á c s

Practical measurements - Practical measurements - ErrorsErrors

Stray lightWavelength error Bandwidth - interpolation,

extrapolationPolarizationDetector systemReference standard