filiu. Each of the algae samples v;hen photosraphed will result 

 in some red^ green^ and blue exposure and hence can be represented 

 by a point in this space. If v;e can find a transformation 

 betvjeen these tv;o three-dimensional spaces, then vie can compute 

 the vector scalars YnjYojYo from the film exposures R, G,B. 



/ 



Ya I = f ; i (2) 



One potential problem here is a situation v;here tvjo samples have 

 different spectral curves and hence plot at different points in 

 the vector space, but give the same film exposures . If such 

 metamers exist, there can be no transformation between the tv;o 

 coordinate systems. Assuming that a transformation can be 

 found, v/e can compute the vector scalars from the film exposures 

 and then construct the spectral curve from the vector amounts -- 

 Y]_,Y2jY3 and the vectors V^,Y2,'^^ plus the average curve Av (Eq. l) . 



Ho^^; can we calibrate a film to apply this procedure? 

 First, it is necessary to obtain spectral curves of a number of 

 samples v/hich represent the population to be studied. The number 

 of samples required v;ould depend on the nature of the population. 



31-10 



