In this paper, we propose a method for detecting digital processing of video such as compositing. Our method is based on a realistic model of charge coupled device (CCD) sensor noise. It allows the identification of an object that has been composited with an image. This is accomplished through the comparison of local characteristics of noise. These characteristics should be constant for an image captured by one camera. However, when an element captured with a different camera is composited with an image, the local noise characteristics of the foreign element can help us identify it. Experimental results validate our model.