The fusion scores calculated by the traditional product rule for multimodal information fusion have a narrow dynamic range

thus the fusion performance of this method is usually not ideal.Under the assumption that all the modes can work properly at the same time

this paper introduces the improved product rule for multimodal information fusion.The basic idea is to increase the dynamic range of fusion scores by smoothing the probability densities and fusion scores.Two experiments have shown that the recognition rate based on the improved product rule is increased.Finally

this paper presents a method for calculating the upper bound of recognition rate of the integrated system by an ideal fusion approach under the given recognition rate of each mode.