www.ams.com Revision 1.0 / 26/08/13 page 1/16
DN40
Lux and CCT Calculations using ams Color Sensors
Application Note:
DN40
-
Rev 1.0
–
Lux and CCT
Calculations using ams Color Sensors
DN40-InsertApp#
Lux and CCT Calculations using ams Color Sensors
www.ams.com Revision 1.0 / 26/08/13 page 2/16
Table of Contents
1
General Description ............................................................................................................. 3
2
Naming Convention.............................................................................................................. 3
3
Calculations .......................................................................................................................... 4
3.1
IR Rejection .......................................................................................................................... 4
3.2
Lux Calculations ................................................................................................................... 5
3.3
Glass Attenuation Factor (GA) ............................................................................................. 5
3.4
CT Calculations .................................................................................................................... 6
3.5
Device Count Saturation ...................................................................................................... 6
3.6
Ripple Rejection ................................................................................................................... 7
3.7
Ripple Saturation .................................................................................................................. 7
3.8
Light Sources ....................................................................................................................... 7
3.9
Maximum Lux value ............................................................................................................. 8
3.10
Lux Accuracy ........................................................................................................................ 8
3.11
Equalization .......................................................................................................................... 8
3.12
Color Saturation ................................................................................................................... 9
3.13
Extending the Sensitivity Range ........................................................................................ 10
3.14
Low Count Level and Autogain .......................................................................................... 11
3.15
Efficient Integer Calculations ............................................................................................. 11
3.16
Dark Glass or Ink on Glass ................................................................................................ 12
APPENDIX I: Coefficients for Lux and CT Equations ...................................................................... 13
APPENDIX II: Data Structures ......................................................................................................... 15
Revision History
Revision Date Owner Description
1.0 26.08.2013 H. Burton Designer’s Notebook – Lux and CC Calculation