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This paper investigates the influence of heterogeneity on mechanical and acoustic emission (AE) behaviours of stratified rock specimens under uniaxial compression using a digital image processing (DIP)-based finite difference method (FDM). In the DIP, a developed image segmentation algorithm based on seeded region growing (SRG) is proposed to fully acquire the mesostructure of stratified rock specimens, instead of the traditional threshold value method. To sufficiently capture the heterogeneity of stratified rock, Weibull statistical manner is adopted to describe mechanical properties of each material component. Three schemes are adopted to study the effect of heterogeneity with different homogeneity index and different mesostructure under two compression loading conditions. The results show that heterogeneity has a great influence on the mechanical and AE behaviours of stratified rock. As the homogeneity of material components increases, the peak strength and brittleness of rocks increase, and the macro elastic modulus improves as well. Simultaneously, the AE modes change from swarm shock to main shock. Under the same component content, the macro-property is better while the component distribution is concentrative relatively, especially to the property of strength. For the coupling effect of mesostructure and heterogeneity arising from material components, mesostructure is considered to cause the visible increase of AE counts. And the numerical results agree well with the previously numerical results and experimental data. [ABSTRACT FROM AUTHOR]