Method for reconstructing a colour image acquired by a photosensitive sensor of size H × W, covered with a mosaic , of size H × W, of P filters of different colours making up a base pattern of size h × w such that h < H and w < W, said base pattern of the mosaic of filters being repeated so as to cover the mosaic of filters without overlap between the base patterns , said method being carried out by computer and being characterized in that it comprises at least the following steps: • a first preliminary step of constructing a demosaicing matrix D starting from a simulation using a first database of N images I i ,i ∈ [1,..., N ], with P colour components, called reference images, for producing a second database of N images J i , i ∈ [1,..., N ] simulating images produced originating from the sensor , after acquisition by said sensor of the images of the first database, said reference images I i and images produced J i being represented respectively in the form of matrices of HW /( hw ) vectors y 1 , x 1 such that: - the components of y 1 are the P components of a reduced neighbourhood of size n h × n w of one of the HW /( hw ) base patterns applied to the reference image I i , - the components of x 1 are the components of a reduced neighbourhood of size n h × n w of one of the HW /( hw ) base patterns applied to the image produced J i , with n h > h and n w > w ; • a second step of reconstructing a colour image producing the product of the demosaicing matrix D with a matrix representation of a mosaic image originating from the sensor after acquisition of the colour image by said sensor , said product of the demosaicing matrix D with the matrix representation of the mosaic image using an interpolation of the colour of each pixel of the mosaic image as a function of a neighbourhood, of size n h × n w pixels, of a base pattern of size h × w , corresponding to the base pattern of the mosaic of filters . • a first preliminary step of constructing a demosaicing matrix D starting from a simulation using a first database of N images I i ,i ∈ [1,..., N ], with P colour components, called reference images, for producing a second database of N images J i , i ∈ [1,..., N ] simulating images produced originating from the sensor , after acquisition by said sensor of the images of the first database, said reference images I i and images produced J i being represented respectively in the form of matrices of HW /( hw ) vectors y 1 , x 1 such that: - the components of y 1 are the P components of a reduced neighbourhood of size n h × n w of one of the HW /( hw ) base patterns applied to the reference image I i , - the components of x 1 are the components of a reduced neighbourhood of size n h × n w of one of the HW /( hw ) base patterns applied to the image produced J i , with n h > h and n w > w ; - the components of y 1 are the P components of a reduced neighbourhood of size n h × n w of one of the HW /( hw ) base patterns applied to the reference image I i , - the components of x 1 are the components of a reduced neighbourhood of size n h × n w of one of the HW /( hw ) base patterns applied to the image produced J i , with n h > h and n w > w ; • a second step of reconstructing a colour image producing the product of the demosaicing matrix D with a matrix representation of a mosaic image originating from the sensor after acquisition of the colour image by said sensor , said product of the demosaicing matrix D with the matrix representation of the mosaic image using an interpolation of the colour of each pixel of the mosaic image as a function of a neighbourhood, of size n h × n w pixels, of a base pattern of size h × w , corresponding to the base pattern of the mosaic of filters . <EOS>