1. Method for extracting raw data from a digital image taken by a photographic or cinematographic camera for correcting the extracted raw data and for generating an improved digital image containing the corrected raw data, said method comprising: determining, for each point of said image located by column C and line L of the image, a value V 0 [C, L] consisting of a combination of colour components of the image, expressed as: 
 V 0 [C, L ]=α Red [ C, L ]+β green [ C, L ]+γ blue [ C, L] wherein α, β, γ are coefficients satisfying the following relationship 
 α+β+γ=1 
 α+β+γ≧0 calculating, for each point of the image, a threshold value V Back. (C, L), calculating for each point of the image, raw data consisting in the difference D[C, L] by means of the relations D[C, L]=V Back. −V 0 [C, L] in the case where the image comprises dark data on a bright background and V 0 [C, L]−V Back. in the case where the image comprises bright data on a dark background, and calculating a threshold value V S consisting of a noise contextual datum from at least one contrast histogram and/or from the probability q that a regional maximum of the raw data contains noise, correcting said raw data by using the threshold value V S for: either calculating projective deformation and corrections to be made depending on said projective deformations and/or by comparing for each point of the image the value D[C, L] with said threshold value V S to determine a corrected raw data value D*[C, L] to be extracted in the following way: 
 if D[C, L]<V S then D*[C, L]= 0 
 if D[C, L]≧V S then D*[C, L]=D[C, L] 
 else 
 D*[C, L]=D[C, L]−V S calculating, for each point of the image, a corrected value I*[C, L] from the corrected raw data D*[C, L] by the following relation 
 I*[C, L]=I max −f.D*[C, L] with I max =value of a bright background or 
 I*[C, L]=I min +f.D*[C, L] with I min =value of a dark background storing the corrected value in a memory so as to obtain said improved image.