Petri Kärhä

Senior University Lecturer

Research outputs

  1. 2019
  2. Published

    Flat-field calibration method for hyperspectral frame cameras

    Kokka, A., Pulli, T., Honkavaara, E., Markelin, L., Kärhä, P. & Ikonen, E., 6 Aug 2019, In : Metrologia. 8 p., 055001.

    Research output: Contribution to journalArticleScientificpeer-review

  3. E-pub ahead of print

    Optical Characterization of III-V Multijunction Solar Cells for Temperature-Independent Band Gap Features

    Baumgartner, H., Oksanen, B., Kärhä, P. & Ikonen, E., 2019, In : IEEE Journal of Photovoltaics. 6 p.

    Research output: Contribution to journalArticleScientificpeer-review

  4. 2018
  5. Published

    Uncertainty analysis of total ozone derived from direct solar irradiance spectra in the presence of unknown spectral deviations

    Vaskuri, A., Kärhä, P., Egli, L., Gröbner, J. & Ikonen, E., 20 Jun 2018, In : Atmospheric Measurement Techniques. 11, 6, p. 3595-3610 16 p.

    Research output: Contribution to journalArticleScientificpeer-review

  6. Published

    Relationships between junction temperature, electroluminescence spectrum and ageing of light-emitting diodes

    Vaskuri, A., Kärhä, P., Baumgartner, H., Kantamaa, O., Pulli, T., Poikonen, T. & Ikonen, E., 15 Mar 2018, In : Metrologia. 55, 2, p. S86-S95

    Research output: Contribution to journalArticleScientificpeer-review

  7. Published

    Key comparison CCPR-K1.a as an interlaboratory comparison of correlated color temperature

    Karha, P., Vaskuri, A., Pulli, T. & Ikonen, E., 2 Mar 2018, In : Journal of Physics: Conference Series. 972, 1, 4 p., 012012.

    Research output: Contribution to journalConference articleScientificpeer-review

  8. Published

    LED based reference for wavelength and relative intensity

    Baumgartner, H., Kylmanen, K., Kantamaa, O., Karha, P. & Ikonen, E., 2 Mar 2018, In : Journal of Physics: Conference Series. 972, 1, 5 p., 012010.

    Research output: Contribution to journalConference articleScientificpeer-review

  9. Published

    Out-of-Range Stray Light Characterization of Single-Monochromator Brewer Spectrophotometers

    Pulli, T., Karppinen, T., Nevas, S., Kärhä, P., Lakkala, K., Karhu, J., Sildoja, M-M., Vaskuri, A., Shpak, M., Manoocheri, F. & 4 othersDoppler, L., Gross, S., Mes, J. & Ikonen, E., 2018, In : ATMOSPHERE: OCEAN. 56, 1, p. 1-11 11 p.

    Research output: Contribution to journalArticleScientificpeer-review

  10. 2017
  11. Published

    Method for estimating effects of unknown correlations in spectral irradiance data on uncertainties of spectrally integrated colorimetric quantities

    Karha, P., Vaskuri, A., Mäntynen, H., Mikkonen, N. & Ikonen, E., 18 Jul 2017, In : Metrologia. 54, 4, p. 524-534 11 p.

    Research output: Contribution to journalArticleScientificpeer-review

  12. Published

    Nonlinearity characterization of array spectroradiometers for the solar UV measurements

    Pulli, T., Nevas, S., Gawhary, O. E., Van Den Berg, S., Askola, J., Kärhä, P., Manoocheri, F. & Ikonen, E., 10 Apr 2017, In : Applied Optics. 56, 11, p. 3077-3086 10 p.

    Research output: Contribution to journalArticleScientificpeer-review

  13. Published

    UV exposure in artificial and natural weathering: A comparative study

    Heikkilä, A., Kazadzis, S., Meinander, O., Vaskuri, A., Kärhä, P., Mylläri, V., Syrjälä, S. & Koskela, T., 22 Feb 2017, Radiation Processes in the Atmosphere and Ocean, IRS 2016: Proceedings of the International Radiation Symposium (IRC/IAMAS). AMERICAN INSTITUTE OF PHYSICS, Vol. 1810. 110004

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  14. Published

    Variability of daily UV index in Jokioinen, Finland, in 1995-2015

    Heikkilä, A., Uusitalo, K., Kärhä, P., Vaskuri, A., Lakkala, K. & Koskela, T., 22 Feb 2017, Radiation Processes in the Atmosphere and Ocean, IRS 2016: Proceedings of the International Radiation Symposium (IRC/IAMAS). AMERICAN INSTITUTE OF PHYSICS, Vol. 1810. 5 p. 110003

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  15. Published

    Facility for Determining Action Spectra of UV Photodegradation

    Vaskuri, A., Kärhä, P., Anu, H. & Ikonen, E., 2017, Radiation Processes in the Atmosphere and Ocean (IRS2016): Proceedings of the International Radiation Symposium (IRC/IAMAS). Davies, R., Egli, L. & Schmutz, W. (eds.). p. 1-4 4 p. 110011. (AIP Conference Proceedings; vol. 1810).

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  16. Published

    Monte Carlo analysis of uncertainty of total atmospheric ozone derived from measured spectra

    Kärhä, P., Vaskuri, A., Gröbner, J., Egli, L. & Ikonen, E., 2017, RADIATION PROCESSES IN THE ATMOSPHERE AND OCEAN: International Radiation Symposium (IRC/IAMAS) - Radiation Processes in the Atmosphere and Ocean. AMERICAN INSTITUTE OF PHYSICS, 4 p. 110005. (AIP Conference Proceedings; vol. 1810).

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  17. 2016
  18. Published

    Temperature invariant energy value in LED spectra

    Baumgartner, H., Vaskuri, A., Kärhä, P. & Ikonen, E., 5 Dec 2016, In : Applied Physics Letters. 109, 23, 231103.

    Research output: Contribution to journalArticleScientificpeer-review

  19. Published

    Natural and accelerated ageing of LED lamps

    Baumgartner, H., Renoux, D., Kärhä, P., Poikonen, T., Pulli, T. & Ikonen, E., 1 Dec 2016, In : Lighting Research and Technology. 48, 8, p. 930-942 13 p.

    Research output: Contribution to journalArticleScientificpeer-review

  20. Published

    Model for simulating uncertainties of TOC from multispectral measurements

    Kärhä, P., Vaskuri, A., Nikke, M., Gröbner, J., Egli, L. & Ikonen, E., 20 May 2016.

    Research output: Contribution to conferencePaperScientific

  21. Published

    Out-of-range stray light and NiSO4 filter characterization of single-monochromator Brewers

    Pulli, T., Kärhä, P., Vaskuri, A., Shpak, M., Manoocheri, F., Karppinen, T., Karhu, J., Lakkala, K. & Mes, J., 17 May 2016.

    Research output: Contribution to conferencePaperScientific

  22. Published

    25 years of spectral UV measurements at Sodankylä, Finland

    Lakkala, K., Anu, H., Kärhä, P., I., I., Karppinen, T., Karhu, J., Lindfors, A. V. & Meinander, O., 22 Apr 2016, p. 363.

    Research output: Contribution to conferencePaperScientific

  23. Published

    Quantifying exceptionality of UV indices in Jokioinen, Finland, over the years 1995-2015

    Heikkilä, A., Uusitalo, K., Kärhä, P., Vaskuri, A., Kaurola, J., Lakkala, K. & Koskela, T., 22 Apr 2016, p. 385.

    Research output: Contribution to conferencePaperScientific

  24. Published

    Sensitivity analysis of ozone retrieval using UV measurements and different retrieval methods

    Egli, L., Gröbner, J., Blumthaler, M., Gawhary, O. E., Kärhä, P., Ingo, K., Alberto, R. & Mark, W., 22 Apr 2016, p. 74.

    Research output: Contribution to conferencePaperScientific

  25. Published

    UV Ageing Facility for Determining Action Spectra of Photodegradation for Translucent Materials

    Vaskuri, A., Kärhä, P., Anu, H. & Ikonen, E., 22 Apr 2016, p. 329.

    Research output: Contribution to conferencePaperScientific

  26. Published

    Out-of-range stray light characterization of single-monochromator Brewer spectrophotometer

    Pulli, T., Kärhä, P., Karppinen, T., Karhu, J., Lakkala, K., Vaskuri, A., Shpak, M. & Mes, J., Mar 2016, In : UVNews. 11, p. 20-23 4 p.

    Research output: Contribution to journalArticleScientific

  27. Published

    Review of challenges and disadvantages of possible LED-based photometric standards

    Poikonen, T., Pulli, T., Dönsberg, T., Baumgartner, H., Kärhä, P. & Ikonen, E., 2016, Proceedings of CIE 2016 Lighting Quality and Energy Efficiency, Melbourne, Australia. CIE

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  28. Published

    Uncertainty evaluation of spectral integrals for LED lamps

    Pulli, T., Vaskuri, A., Mäntynen, H., Kärhä, P. & Ikonen, E., 2016, PROCEEDINGS OF CIE 2016 LIGHTING QUALITY AND ENERGY EFFICIENCY. CIE, p. 89-93 5 p.

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  29. 2015
  30. Published

    ACCURATE MEASUREMENT OF ILLUMINANCE AND LUMINOUS EFFICACY OF WHITE LED LAMPS

    Ikonen, E., Pulli, T., Dönsberg, T., Poikonen, T., Manoocheri, F. & Kärhä, P., 2015, 28th CIE SESSION, Manchester, UNITED KINGDOM, June 28 July 4, 2015. Vienna, Austria: CIE, p. 138-139

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientific

  31. Published

    Advantages of white LED lamps and new detector technology in photometry

    Pulli, T., Donsberg, T., Poikonen, T., Manoocheri, F., Karha, P. & Ikonen, E., 2015, In : LIGHT: SCIENCE & APPLICATIONS. 4, 1, p. 00000

    Research output: Contribution to journalArticleScientificpeer-review

  32. Published

    Effects of intelligent control on the lifetime of LED street lights

    Baumgartner, H., Oksanen, J., Poikonen, T., Pulli, T., Kärhä, P. & Ikonen, E., 2015, 28th CIE SESSION, Manchester, UNITED KINGDOM, June 28 July 4, 2015. Vienna, Austria: CIE, p. 1662-1668

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientific

  33. Published

    High-resolution setup for measuring wavelength sensitivity of photoyellowing of translucent materials

    Vaskuri, A., Karha, P., Heikkila, A. & Ikonen, E., 2015, In : Review of Scientific Instruments. 86, 10, p. 1-8 103103.

    Research output: Contribution to journalArticleScientificpeer-review

  34. Published

    High-resolution setup for measuring wavelength sensitivity of photoyellowing of translucent materials

    Vaskuri, A., Kärhä, P., Heikkilä, A. & Ikonen, E., 2015.

    Research output: Contribution to conferencePaperScientific

  35. Published

    Mathematical limitations of the CIE mesopic photometry system

    Shpak, M., Kärhä, P. & Ikonen, E., 2015, In : Lighting Research and Technology. 49, 1, p. 111-121

    Research output: Contribution to journalArticleScientificpeer-review

  36. Published

    Methods for decreasing uncertainties in LED photometry

    Dönsberg, T., Pulli, T., Sildoja, M., Poikonen, T., Baumgartner, H., Manoocheri, F., Kärhä, P. & Ikonen, E., 2015, 17th International Congress of Metrology (CIM 2015), Paris, France, September 21-24, 2015. Larquier, B. (ed.). EDP SCIENCES

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  37. Published

    Modeling the spectral shape of InGaAlP-based red light-emitting diodes

    Vaskuri, A., Baumgartner, H., Kärhä, P., Andor, G. & Ikonen, E., 2015, In : Journal of Applied Physics. 118, 20, p. 203103

    Research output: Contribution to journalArticleScientificpeer-review

  38. Published

    Photoyellowing of transparent materials as quantified with a setup of lasers

    Heikkilä, A., Vaskuri, A. & Kärhä, P., 2015, 7th European Weathering Symposium, Naples, Italy, September 16-18, 2015. Reichert, T. (ed.). Germany: Gesellshaft für Umweltsimulation e.V. GUS, p. 209-218

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  39. Published

    TOWARDS LED-BASED PHOTOMETRIC STANDARDS

    Poikonen, T., Pulli, T., Dönsberg, T., Baumgartner, H., Kärhä, P. & Ikonen, E., 2015, 28th CIE SESSION, Manchester, UNITED KINGDOM, June 28 July 4, 2015. Vienna, Austria: CIE

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientific

  40. 2014
  41. Published

    Adjustable power line impedance emulator for characterisation of energy-saving lighting products

    Poikonen, T., Koskinen, T., Baumgartner, H., Kärhä, P. & Ikonen, E., 2014, CIE 2014 Lighting quality and energy efficiency conference, Kuala Lumpur, Malaysia, April 23-26, 2014. CIE, p. 403-407

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  42. Published

    Adjustable Power Line Impedance Emulator for Characterization of Energy-Saving Lamps

    Poikonen, T., Koskinen, T., Baumgartner, H., Kärhä, P. & Ikonen, E., 2014, Newrad 2014, Espoo, Finland, June 24-27, 2014. Park, S., Kärhä, P. & Ikonen, E. (eds.). Espoo: Aalto University, p. 348-349

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  43. Published

    Advantages of a two-channel luminance meter for photopic and scotopic measurements in determining mesopic luminance

    Kärhä, P., Shpak, M. & Ikonen, E., 2014, International conference on New Developments and Applications in Optical Radiometry (Newrad), Espoo, Finland, June 24-27, 2014. Park, S., Kärhä, P. & Ikonen, E. (eds.). Espoo: Aalto University, p. 261-262

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  44. Published

    A temperature controller for high power light emitting diodes based on resistive heating and liquid cooling

    Baumgartner, H., Vaskuri, A., Kärhä, P. & Ikonen, E., 2014, In : Applied Thermal Engineering. 71

    Research output: Contribution to journalArticleScientificpeer-review

  45. Published

    Calibration of spectral responsivity of imaging devices using led light sources

    Ikonen, E., Hirvonen, J-M., Poikonen, T., Vaskuri, A. & Kärhä, P., 2014, CIE 2014 Lighting Quality and Energy Efficiency Conference, Kuala Lumpur, April 23-26 2014.

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  46. Published

    Characterisation of nonlinearities of array spectroradiometers

    Kärhä, P., Nevas, S., Blattner, P., Gawhary, O. E., Pulli, T., Egli, L. & Gröbner, J., 2014, Davos, Switzerland.

    Research output: Working paperProfessional

  47. Published

    Characterisation of nonlinearities of array spectroradiometers in use for measurements of the terrestrial solar UV irradiance

    Nevas, S., Blattner, P., El Gawhary, O., Pulli, T., Kärhä, P., Egli, L. & Gröbner, J., 2014, International conference on New Developments and Applications in Optical Radiometry (Newrad), Espoo, Finland, June 24-27, 2014. Park, S., Kärhä, P. & Ikonen, E. (eds.). Espoo: Aalto University, p. 89-90

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  48. Published

    Characterisation of nonlinearities of array spectroradiometers in use for measurements of the terrestrial solar UV irradiance

    Nevas, S., Blattner, P., El Gawhary, O., Pulli, T., Kärhä, P., Egli, L. & Gröbner, J., 2014, In : UVNews. 10, p. 9-11

    Research output: Contribution to journalArticleScientificpeer-review

  49. Published

    Characterization of array spectroradiometers for solar UV measurements

    Egli, L., Nevas, S., Blattner, P., El Gawhary, O., Kärhä, P. & Gröbner, J., 2014, CIE Expert Symposium on Measurement Uncertainties in Photometry and Radiometry for Industry, Vienna, Austria, September 12, 2014. Vienna, Austria: Comission International de l'Eclairage (CIE), p. 22

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  50. Published

    High-Resolution Setup for Measuring Photoyellowing of Transparent Materials

    Vaskuri, A., Kärhä, P., Mylläri, V., Heikkilä, A. & Ikonen, E., 2014, p. 300-302.

    Research output: Working paperProfessional

  51. Published

    Improved diffusers for spectroradiometers measuring solar irradiance

    Kärhä, P., Mes, J., Pulli, T., Schreder, J., Partosoebroto, A., Hülsen, G., Askola, J. & Gröbner, J., 2014, In : UVNews. 10, p. 25-27

    Research output: Contribution to journalArticleScientificpeer-review

  52. Published

    Irradiance scale of long term UV measurements at Sodankylä and Jokioinen, Finland

    Lakkala, K., Koskela, T. & Kärhä, P., 2014, International conference on New Developments and Applications in Optical Radiometry (Newrad), Espoo, Finland, June 24-27, 2014. Park, S., Kärhä, P. & Ikonen, E. (eds.). Espoo: Aalto University, p. 51-52

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  53. Published

    Luminance meter for photopic and scotopic measurements in the mesopic range

    Shpak, M., Kärhä, P., Porrovecchio, G., Smid, M. & Ikonen, E., 2014, In : Measurement Science and Technology. 25, 9

    Research output: Contribution to journalArticleScientificpeer-review

  54. Published

    Measurement of relative spectra of LEDs

    Baumgartner, H., Vaskuri, A., Poikonen, T., Dönsberg, T., Pulli, T., Oksanen, J., Kärhä, P. & Ikonen, E., 2014, International conference on New Developments and Applications in Optical Radiometry (Newrad), Espoo, Finland, June 24-27, 2014. Park, S., Kärhä, P. & Ikonen, E. (eds.). Espoo: Aalto University, p. 142-143

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  55. Published

    Natural and Accelerated Ageing of Solid State Lamps

    Kärhä, P., Baumgartner, H., Vaskuri, A., Renoux, D. & Ikonen, E., 2014, International conference on New Developments and Applications in Optical Radiometry (Newrad), Espoo, Finland, June 24-27, 2014. Park, S., Kärhä, P. & Ikonen, E. (eds.). Espoo: Aalto University, p. 310-311

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

  56. Published

    New source and detector technology for the realization of photometric units

    Dönsberg, T., Sildoja, M., Manoocheri, F., Pulli, T., Poikonen, T., Baumgartner, H., Kärhä, P. & Ikonen, E., 2014, Optics and Photonics Days 2014, Turku, Finland, May 21, 2014.

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientific

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