ABSTRACT
Some methods that utilized experimental techniques to eliminate the background have been developed with the increasing use of LIBS recently. The two most common ways to correct continuum background are blank measurement method and off-peak background correction method [6-9]. The blank measurement method needs separate measurement of the instantaneous emission profile of a blank and the analyte emission. The background correction based on two profiles subtraction. The blank measurement method is not satisfactory if the instantaneous profiles of the blank and the sample do not match exactly [10]. Using the off-peak background correction method, the background
high weight to high quality signal. For the balance calculation, we can introduce a vector of weights wi corresponding to the original signal Y. The vector of weights is therefore introduced in the fidelity part z to the LIBS emission intensity y can be expressed as:
y Wi i
i i Tw = ( )Y Z
2( )z ( )Y Z− (1)
where the weights value wi corresponding to the original signal Y, W is a diagonal matrix with wi on its diagonal. The weights wi can take two values depending on the relative contribution of the original signal Y and background Z at point i: w pi if y zi i and w pi 1 , otherwise. The parameter p is called the asymmetry parameter. This parameter may take values ranging from 0 to 1.
