The accurate modeling of the acquisition process in digital cameras is of great interest for a wide variety of domains concerning the use of digital images. In particular, it is of great utility in image processing, computational photography or computer vision applications. For instance, the statistical characterization of image data allows to develop denoising techniques suited to particular noise types, which perform much better than general techniques. In the present report we present a detailed analysis of the digital image acquisition process which allows us to introduce a statistical model of the raw sensor data. The accuracy of this modeling is essential to its posterior utility. It is thus fundamental to take into account all different sources of noise and uncertainty in this model.