摘要： Understanding the image formation inside plenoptic cameras is significant for the investigations of improving the low spatial resolution. Most researches explore the image formation from the perspective of geometric optics. However, as the hardware components in combination with low-aperture optical systems become smaller and smaller, geometric analysis will no longer be valid due to diffraction effects. In this paper, a wave-optic-based model is proposed that uses the Fresnel diffraction equation to propagate the whole object field into the plenoptic systems. The proposed model employs averaging of intensities on the sensor from uncorrelated coherent wave to avoid interference during propagations among the optical component planes. Besides, by utilizing the method of multiple partial propagations, the proposed model is much flexible at sampling on propagation planes. In order to verify the effectiveness of the proposed model, numerical simulations are conducted by comparing with existing wave optic model under different optical configurations of plenoptic cameras. Results demonstrate that the proposed model can describe the light field image formation properly. In addition, the time for image formation has been reduced by a factor of 19.22 using the proposed model.