In this work, speckle visibility spectroscopy (SVS) and imaging techniques are used to study the accumulation phenomenon during the continuous flow of irregular particles in a rotating drum. This phenomenon is caused by the rapid dissipation of kinetic energy in particles. First, we use the SVS method to measure the granular temperature of the flow-layer surface. Then, we calculate the differential curve of the granular temperature with respect to position. The position of the global maximum of the differential curve is found to be consistent with that of the accumulation area captured by imaging techniques, allowing the quantitative calculation of the size and position of the accumulation region. The results show that increasing the drum speed causes the area of the accumulation region to increase and the accumulation region to move downwards. In addition, increasing the particle size also leads to an increase in the area of the accumulation region. (C) 2019 Published by Elsevier B.V.