A method for counting particles , known as particles of interest, arranged in a sample , the method comprising the following steps: a) illumination of the sample with the aid of a light source , the light source emitting an incident light wave propagating toward the sample ; b) acquisition, with the aid of an image sensor , of an image ( I 0 ) of the sample , formed in a detection plane ( P 0 ), the sample being arranged between the light source and the image sensor , each image being representative of a light wave , known as the exposition wave, to which the image sensor is exposed under the effect of said illumination; the method being characterized in that it also comprises the following steps: c) based on the image acquired ( I 0 ) during step b), application of a propagation operator ( h ) so as to calculate a complex expression ( A z ) of the exposition wave , along a reconstruction surface ( P z ) extending opposite the detection plane ( P 0 ); d) formation of an image ( I z ,M z ,φ z ), known as the reconstructed image, representative of a distribution of the modulus or of the phase of the complex expression along the reconstruction surface; e) segmentation of the image formed during step d) to obtain a segmentation image I z ∗ , containing regions of interest ( ROI ) spaced apart from each other, all or some of the regions of interest being associated with at least one particle of interest; f) determination of a size of regions of interest, and classification of said regions of interest as a function of their size according to at least one of the following classes: - a class such that the region of interest contains a single particle of interest; - a class such that the region of interest contains a whole number, greater than 1, of particles of interest; g) counting of the particles of interest based on the regions of interest which underwent a classification during step f). a) illumination of the sample with the aid of a light source , the light source emitting an incident light wave propagating toward the sample ; b) acquisition, with the aid of an image sensor , of an image ( I 0 ) of the sample , formed in a detection plane ( P 0 ), the sample being arranged between the light source and the image sensor , each image being representative of a light wave , known as the exposition wave, to which the image sensor is exposed under the effect of said illumination; the method being characterized in that it also comprises the following steps: c) based on the image acquired ( I 0 ) during step b), application of a propagation operator ( h ) so as to calculate a complex expression ( A z ) of the exposition wave , along a reconstruction surface ( P z ) extending opposite the detection plane ( P 0 ); d) formation of an image ( I z ,M z ,φ z ), known as the reconstructed image, representative of a distribution of the modulus or of the phase of the complex expression along the reconstruction surface; e) segmentation of the image formed during step d) to obtain a segmentation image I z ∗ , containing regions of interest ( ROI ) spaced apart from each other, all or some of the regions of interest being associated with at least one particle of interest; f) determination of a size of regions of interest, and classification of said regions of interest as a function of their size according to at least one of the following classes: - a class such that the region of interest contains a single particle of interest; - a class such that the region of interest contains a whole number, greater than 1, of particles of interest; - a class such that the region of interest contains a single particle of interest; - a class such that the region of interest contains a whole number, greater than 1, of particles of interest; g) counting of the particles of interest based on the regions of interest which underwent a classification during step f). <EOS>