A calibration procedure to obtain solid concentrations from digital imagesof bulk powders

In this work, different approaches to obtain calibration curves of powder c oncentration from digital images of bulk materials are reviewed and compare d. It is shown here that a logarithmic relation between the grey scale valu es of the bed images and the powder volume fraction produces a high quality calibration curve without the need of fitting constants. This conclusion i s valid both for our experimental data and other previously published that have used polynomial equations to define calibration curves. (C) 2001 Elsev ier Science S.A. All rights reserved.