Method for processing the image delivered by a colour image sensor comprising a mosaic of N coloured pixels arranged in a regular geographic distribution of three colours in which each pixel is associated with one point of the image to be established, each pixel delivering a digital signal whose value represents the luminance component of an image point in the colour corresponding to that pixel, the signals arising from the N pixels being arranged in a matrix and the image processing operation comprising a calculation of interpolating signals of the matrix, allowing each image point to be given three digital values of luminance components corresponding respectively to the three colours, while the pixel corresponding to that image point delivers a signal corresponding to a single colour, method characterized in that it comprises the following steps: - defining a first elementary matrix filter, which is a bilinear interpolation filter, of size mxm, m being an odd number greater than or equal to 3; - defining a low-pass matrix filter of size nxn, n being an odd number greater than or equal to 3; - defining a high-pass matrix filter, complementary to the low-pass filter, of size nxn; - convoluting the first matrix filter with the low-pass filter, resulting in a low-frequency interpolation filter of size (m+n-1)x(m+n-1); - convoluting the first matrix filter with the high-pass filter, resulting in a high-frequency interpolation filter of size (m+n-1)x(m+n-1); - filtering the matrix of digital signals, using the pixels of the first colour only, with the low-frequency interpolation filter, filtering the matrix of digital signals, using the pixels of the second colour only, with the low-frequency interpolation filter, and filtering the matrix of digital signals, using the pixels of the third colour only, with the low-frequency interpolation filter, these three filtering operations resulting in a first intermediate digital value being given to each point of the image for each of the colours; - filtering the entire matrix of digital signals with the high-frequency interpolation filter, without taking the colours into account, in order to establish a second intermediate digital value for each point of the image; - adding, for each pixel, in order to obtain a digital value of a given colour of that pixel, the first intermediate digital value corresponding to that pixel and to that colour, and the second digital value corresponding to that pixel. - defining a first elementary matrix filter, which is a bilinear interpolation filter, of size mxm, m being an odd number greater than or equal to 3; - defining a low-pass matrix filter of size nxn, n being an odd number greater than or equal to 3; - defining a high-pass matrix filter, complementary to the low-pass filter, of size nxn; - convoluting the first matrix filter with the low-pass filter, resulting in a low-frequency interpolation filter of size (m+n-1)x(m+n-1); - convoluting the first matrix filter with the high-pass filter, resulting in a high-frequency interpolation filter of size (m+n-1)x(m+n-1); - filtering the matrix of digital signals, using the pixels of the first colour only, with the low-frequency interpolation filter, filtering the matrix of digital signals, using the pixels of the second colour only, with the low-frequency interpolation filter, and filtering the matrix of digital signals, using the pixels of the third colour only, with the low-frequency interpolation filter, these three filtering operations resulting in a first intermediate digital value being given to each point of the image for each of the colours; - filtering the entire matrix of digital signals with the high-frequency interpolation filter, without taking the colours into account, in order to establish a second intermediate digital value for each point of the image; - adding, for each pixel, in order to obtain a digital value of a given colour of that pixel, the first intermediate digital value corresponding to that pixel and to that colour, and the second digital value corresponding to that pixel.