1. Method of detecting and quantifying blur in a digital image, making use of a computer and comprising: a step a) of obtaining a digital image comprising pixels and colorimetric coding parameters associated with the pixels; a step b) of obtaining a brightness parameter for each pixel, from the digital image, said step b) comprising a convolution operation with an edge detection matrix; a step c) of calculating a score S1 comprising the maximum, calculated over all the pixels, of the brightness parameter obtained in step b); and a step d) of evaluating the digital image, the digital image being considered to be blurred if the score S1 obtained in step c) is strictly less than a first predetermined threshold, the score S1 providing a first quantity of blur present in the digital image, wherein: in step c), a second score S2 is calculated including a quotient which comprises: in the numerator, the sum, calculated over all the pixels, of the brightness parameters obtained in step b) which exceed a predetermined brightness threshold, and in the denominator, the sum, calculated over all the pixels, of the brightness parameters obtained in step b); and in step d), the digital image is also considered to be blurred if the score S2 obtained in step c) is strictly less than a second predetermined threshold, the score S2 additionally providing a second quantity of blur present in the digital image.