This paper describes an analysis on the granular noise in pixel-to-pixel mapping-based computational integral imaging. The pixel mapping-based method provides a high-resolution reconstructed images and also its computational cost is very lower than the previous back-projection-based method. In this paper, a signal model for the pixel mapping-based method is introduced, which defines and analyzes the granular noise. Computer experiments provides the granular noise properties based on the proposed signal model. The experimental results indicates that the granular noise pattern differs from that of the back-projection based method. The results is also utilized in the pixel mapping-based method.