A method for acquiring a coloured image by scanning a coloured surface of a tile, comprising steps of: providing a matrix of photodetectors comprising a plurality of rows of photodetectors which are parallel and placed side by side, the matrix of photodetectors does not comprise any colour filter above the photodetectors and the rows of photodetectors are near each other and spaced by a distance equal to at least one pixel, wherein each row of photodetectors is able to detect the image of an elementary strip of a surface band of a coloured surface to be scanned of a tile; positioning the matrix of photodetectors such as to acquire an image of the surface band of a coloured surface a tile, with each row of photodetectors such as to acquire the image of a corresponding elementary strip of the surface band commanding the matrix of photodetectors such as to acquire the image of the surface band in synchrony with a temporal scanning interval, wherein for each temporal scanning interval each row of photodetectors acquires the image of a corresponding elementary strip of the surface band; providing a plurality of lamps each having a light emission spectrum different from the light emission spectrum of a further lamp of the plurality of lamps; positioning the plurality of lamps such as to illuminate the surface band of the coloured surface to be scanned of the tile; commanding the lamps of the plurality of lamps in a switching-on cycle sequence wherein only one of the lamps at a time is commanded to switch on for each temporal scanning interval; providing conveyor means for restingly receive and transport the tile to be scanned and for determining a relative movement between the tile, on one side, and the matrix of photodetectors and the plurality of lamps, on the other side, in a movement direction which is perpendicular to the plurality of rows of photodetectors such that for each surface band of the coloured surface to be scanned of the tile a predetermined number of images is acquired, J wherein the conveyor means are activated so as to displace the tile in a stepped motion after each temporal scanning interval, with each step corresponding to the width of an elementary strip of the surface band so that for each switching-on cycle of the lamps the conveyor means move the tile so as the tile is wholly displaced by a quantity equal to the width of the surface band so that the image of each elementary strip of the surface band is successively acquired by all the rows of photodetectors. providing a matrix of photodetectors comprising a plurality of rows of photodetectors which are parallel and placed side by side, the matrix of photodetectors does not comprise any colour filter above the photodetectors and the rows of photodetectors are near each other and spaced by a distance equal to at least one pixel, wherein each row of photodetectors is able to detect the image of an elementary strip of a surface band of a coloured surface to be scanned of a tile; positioning the matrix of photodetectors such as to acquire an image of the surface band of a coloured surface a tile, with each row of photodetectors such as to acquire the image of a corresponding elementary strip of the surface band commanding the matrix of photodetectors such as to acquire the image of the surface band in synchrony with a temporal scanning interval, wherein for each temporal scanning interval each row of photodetectors acquires the image of a corresponding elementary strip of the surface band; providing a plurality of lamps each having a light emission spectrum different from the light emission spectrum of a further lamp of the plurality of lamps; positioning the plurality of lamps such as to illuminate the surface band of the coloured surface to be scanned of the tile; commanding the lamps of the plurality of lamps in a switching-on cycle sequence wherein only one of the lamps at a time is commanded to switch on for each temporal scanning interval; providing conveyor means for restingly receive and transport the tile to be scanned and for determining a relative movement between the tile, on one side, and the matrix of photodetectors and the plurality of lamps, on the other side, in a movement direction which is perpendicular to the plurality of rows of photodetectors such that for each surface band of the coloured surface to be scanned of the tile a predetermined number of images is acquired, J wherein the conveyor means are activated so as to displace the tile in a stepped motion after each temporal scanning interval, with each step corresponding to the width of an elementary strip of the surface band so that for each switching-on cycle of the lamps the conveyor means move the tile so as the tile is wholly displaced by a quantity equal to the width of the surface band so that the image of each elementary strip of the surface band is successively acquired by all the rows of photodetectors.