Measurement Methods and Characterisation of the Optical Parameters of Wood

The chapter deals with the measurement methods and characterisation of basic optical parameters. In the first section the physical backgrounds of the photonPhoton-wood interaction are discussed. Definitions of basic optical parameters are introduced and the fundaments of reflectance measurement are presented. It also introduces the methods in regards to the determination of the absorbance data from the measured reflectance parameters. The chapter reviews the basics of reflectance measurement in the ultraviolet, visible, near- and middle infrared radiation ranges. Several suggestions and recommendations are given for correct measurement and data processing. Drawbacks of attenuated total reflectance measurement method for porous samples like wood is presented, together with the usual mistakes of data processing. Difference spectrumDifference spectrum method is introduced as an excellent method to follow the chemical changes during different treatments in the infrared radiation region. It is also demonstrated how the position of maximum of overlapping absorption bands can alter if the intensity of the individual bands change a different extent.