We present an approach to solving inverse problems based on classification of isotropic ensembles of non-spherical particles. The hypothesis that equivalent ensembles have close extinction coefficients is formulated and checked. The results are illustrated by numerical calculations of extinction coefficients for randomly oriented ellipsoidal particles, hexagonal and circular cylinders. The absorption coefficients for the pigment mixture of Spirulina platensis within the photosynthetic band (l = 410 to 700 nm) are estimated. The degree of destruction of chloroplasts under mechanical effect is calculated.