1. A method for calibrating a digital imager using a sequence of P input images acquired beforehand by the imager, to which images a calibrating image is applied to obtain a sequence of P output images, wherein the calibration is carried out by updating the calibrating image by estimating, in an iteration n, n being an integer higher than or equal to 1, an image representative of the calibrating image, wherein an initial image representative of the calibrating image is defined, wherein a mathematical transformation that is able to transform an output image into an image that is what is called the transform of the output image, and for which there exists another mathematical transformation, called the inverse transformation, capable of transforming the transform of the output image into the image that is what is called the inverse transform of the transform of the output image, is chosen, and wherein the estimation of the image representative of the calibrating image comprises the following steps: transforming the at least one P output images, each transformation giving an image of the transform of the output image; estimating an image representative of the transform of an image of a deviation between the initial image representative of the calibrating image and the calibrating image from the representative images and images of the transform of the output image of the preceding iterations; inversely transforming the representative image to obtain the image of the deviation; and combining the initial image and the image of the deviation and obtaining the image representative of the calibrating image.