Document processing method in a system comprising on the one hand, a device suitable for supplying successive captured images and, on the other hand, a background surface; said system storing a current background surface image; said processing method comprising the following steps: /a/ detecting the presence of a moving document in a series of captured images with respect to the current background surface image; /b/ monitoring said movement of the document within said series of images; /c/ detecting the end of the movement of said document; and /d/ updating the current background surface image; wherein, in step /b/, the movement of the document is monitored by determining document extraction masks respectively for the captured images, the extraction mask of a captured image being obtained according to the following steps: /i/ obtaining an entropy map on the basis of a difference in grey levels between the current background surface image and the given captured image, said entropy map associating respective entropy values with the pixels of the image; /ii/ normalizing the entropy values of said entropy map by obtaining standardized entropy values on a scale of 0-255; and /iii/ determining an extraction mask of the document from the captured image corresponding to the pixels of the captured image with which standardized entropy values higher than a threshold value are associated, the method further comprising the following steps on a given captured image: - determining a first zone of said captured image corresponding to the zone that is common to the extraction mask of said captured image and to the extraction mask of the preceding captured image; - determining a second zone corresponding to the extraction mask of said captured image outside of the first zone; and wherein step /iii/ is carried out for the first zone and the second zone of the captured image, a first part of the extraction mask of the captured image corresponding to the pixels of the captured image of the first zone with which standardized entropy values higher than a first threshold value are associated and a second part of the extraction mask of the captured image corresponding to the pixels of the captured image of the second zone with which entropy values higher than a second threshold value are associated; said first threshold value being higher than said second threshold value. /a/ detecting the presence of a moving document in a series of captured images with respect to the current background surface image; /b/ monitoring said movement of the document within said series of images; /c/ detecting the end of the movement of said document; and /d/ updating the current background surface image; /i/ obtaining an entropy map on the basis of a difference in grey levels between the current background surface image and the given captured image, said entropy map associating respective entropy values with the pixels of the image; /ii/ normalizing the entropy values of said entropy map by obtaining standardized entropy values on a scale of 0-255; and /iii/ determining an extraction mask of the document from the captured image corresponding to the pixels of the captured image with which standardized entropy values higher than a threshold value are associated, the method further comprising the following steps on a given captured image: - determining a first zone of said captured image corresponding to the zone that is common to the extraction mask of said captured image and to the extraction mask of the preceding captured image; - determining a second zone corresponding to the extraction mask of said captured image outside of the first zone; and - determining a first zone of said captured image corresponding to the zone that is common to the extraction mask of said captured image and to the extraction mask of the preceding captured image; - determining a second zone corresponding to the extraction mask of said captured image outside of the first zone; and