When two granular phases are brought into motion in a rotating drum, a competition of mixing and segregation occurs. Several image analysis methods have been used to quantify the mixing. In this work, a modification of the contact method, originally proposed by Van Puyvelde et al. (Powder Technol. 106, 183–191 (1999)), is suggested to allow evaluation of the mixing index for each separate image. A strength of this modified method lies in the removal of the case-dependent normalization of the mixing index, which has so far impaired a direct comparison to other studies. This modified method is tested on artificial and experimental images of a granular bed composed of spherical glass and polypropylene beads of equal size. The bed evolves in a rotating drum under the rolling regime. The temporal evolution of the mixing index is in excellent agreement with the commonly used variance method.

当两个颗粒相在转鼓中运动时，就会发生混合和偏析的竞争。几种图像分析方法已用于量化混合。在这项工作中，最初由Van Puyvelde等人提出的接触方法的一种修改。（Powder Technol。106，183–191（1999））建议用于评估每个单独图像的混合指数。这种改进方法的优势在于消除了根据情况进行混合指数的归一化，迄今为止，这已经削弱了与其他研究的直接比较。在由球形玻璃和大小相等的聚丙烯珠组成的颗粒床的人工和实验图像上测试了这种改进的方法。床在滚动状态下在旋转的鼓中演化。