A computer implemented method for generating a color-faithful extended depth-of-field image from a color volume of a biological sample having dimension (N, M, L) and values I( n, m, l), the voxels ( n, m, l) for a fixed / going from 1 to L being images acquired at different focal depths in a z-direction using a microscope, said method comprising the following steps: a) receiving the color volume and generating a grayscale volume by applying an invertible color-to-grayscale transformation to said color volume; b) applying a wavelet transform to the grayscale volume, said application being performed in parallel on each set of NxM voxels of the grayscale volume having a same l index and (n, m) index going from (1,1) to (N, M), so as to obtain a 3D wavelet coefficient matrix wherein the value of each voxel having a (n, m, /) index comprises a set of wavelet coefficients; c) for each group of L voxels of the 3D wavelet coefficient matrix having a same (n, m) index and a / index going from 1 to L, selecting one set of wavelet coefficients using a predefined coefficient selection rule; d) generating: - a 2D wavelet coefficient matrix WCM, wherein the value WCM(n, m) of each pixel having a ( n, m) index is the set of wavelet coefficients selected from the 3D wavelet coefficient matrix by the coefficient selection rule; - a 2D coefficient map CM, wherein the value CM(n, m) of each pixel having a (n, m) index is the / index of the voxel of the 3D wavelet coefficient matrix that comprises the set of wavelet coefficients selected by the coefficient selection rule; e) applying an inverse transformation of the wavelet transform to the 2D wavelet coefficient matrix WCM so as to obtain a 2D grayscale EDF image; f) generating a 2D color composite image CC, wherein the value CC(n, m) of each pixel having (n, m) index is the value I(n, m, l) of the voxel of the color volume having a / index equal to the value CM(n, m) of the 2D coefficient map CM; g) applying an inverse transformation of the invertible color-to-grayscale transformation to the 2D grayscale EDF image to obtain a 2D color EDF image; h) converting the 2D color composite image CC and the 2D color EDF image into a color space comprising two chromaticity components and one intensity component; i) concatenating, the two chromaticity components of the 2D color composite image CC and the intensity component of the 2D color EDF image, to obtain the color-faithful extended depth-of-field image. a) receiving the color volume and generating a grayscale volume by applying an invertible color-to-grayscale transformation to said color volume; b) applying a wavelet transform to the grayscale volume, said application being performed in parallel on each set of NxM voxels of the grayscale volume having a same l index and (n, m) index going from (1,1) to (N, M), so as to obtain a 3D wavelet coefficient matrix wherein the value of each voxel having a (n, m, /) index comprises a set of wavelet coefficients; c) for each group of L voxels of the 3D wavelet coefficient matrix having a same (n, m) index and a / index going from 1 to L, selecting one set of wavelet coefficients using a predefined coefficient selection rule; d) generating: - a 2D wavelet coefficient matrix WCM, wherein the value WCM(n, m) of each pixel having a ( n, m) index is the set of wavelet coefficients selected from the 3D wavelet coefficient matrix by the coefficient selection rule; - a 2D coefficient map CM, wherein the value CM(n, m) of each pixel having a (n, m) index is the / index of the voxel of the 3D wavelet coefficient matrix that comprises the set of wavelet coefficients selected by the coefficient selection rule; - a 2D wavelet coefficient matrix WCM, wherein the value WCM(n, m) of each pixel having a ( n, m) index is the set of wavelet coefficients selected from the 3D wavelet coefficient matrix by the coefficient selection rule; - a 2D coefficient map CM, wherein the value CM(n, m) of each pixel having a (n, m) index is the / index of the voxel of the 3D wavelet coefficient matrix that comprises the set of wavelet coefficients selected by the coefficient selection rule; e) applying an inverse transformation of the wavelet transform to the 2D wavelet coefficient matrix WCM so as to obtain a 2D grayscale EDF image; f) generating a 2D color composite image CC, wherein the value CC(n, m) of each pixel having (n, m) index is the value I(n, m, l) of the voxel of the color volume having a / index equal to the value CM(n, m) of the 2D coefficient map CM; g) applying an inverse transformation of the invertible color-to-grayscale transformation to the 2D grayscale EDF image to obtain a 2D color EDF image; h) converting the 2D color composite image CC and the 2D color EDF image into a color space comprising two chromaticity components and one intensity component; i) concatenating, the two chromaticity components of the 2D color composite image CC and the intensity component of the 2D color EDF image, to obtain the color-faithful extended depth-of-field image.