A method for measuring a particles' precipitation rate, said method comprising the steps of: - acquiring at least one first image during a precipitation event through an image acquisition device having a sensor and a lens ; and - detecting said particles of said precipitation in said at least one first image by subtracting a background of said first image and setting a brightness threshold (S 1 ) for detecting said particles, said particles being visible as a plurality of streaks in said image, wherein a first portion of said plurality of streaks comprises blurred streaks, and a second portion of said plurality of streaks comprises focused streaks; characterized in that said method comprises the steps of: - determining from said at least one first image a blurred diameter ( D P,b ) and a blurred length ( L P,b ) for said plurality of streaks; - estimating an actual diameter ( D P ) and an actual length ( L P ) for said plurality of streaks by resolving an equations' system having three equations and three unknowns, namely said actual diameter ( D P ) , said actual length ( L P ) and a depth position ( z ) of said plurality of streaks, said depth position (z) being the distance of each particle from said lens , in which a first equation has said actual diameter ( D P ) as unknown in function of said depth position ( z ), a second equation has said actual length ( L P ) as unknown in function of said depth position ( z ) and a third equation equals the theoretical terminal velocity of said particles to an estimated velocity ( v ) of said particles in function of said depth position ( z ); - wherein said velocity ( v ) of said particles is estimated based on the ratio between a net streak length and an exposure time ( t e ) used to take said at least one first image; - estimating said particles' precipitation rate based on said actual diameter ( D P ) and said velocity ( v ). - acquiring at least one first image during a precipitation event through an image acquisition device having a sensor and a lens ; and - detecting said particles of said precipitation in said at least one first image by subtracting a background of said first image and setting a brightness threshold (S 1 ) for detecting said particles, said particles being visible as a plurality of streaks in said image, wherein a first portion of said plurality of streaks comprises blurred streaks, and a second portion of said plurality of streaks comprises focused streaks; - determining from said at least one first image a blurred diameter ( D P,b ) and a blurred length ( L P,b ) for said plurality of streaks; - estimating an actual diameter ( D P ) and an actual length ( L P ) for said plurality of streaks by resolving an equations' system having three equations and three unknowns, namely said actual diameter ( D P ) , said actual length ( L P ) and a depth position ( z ) of said plurality of streaks, said depth position (z) being the distance of each particle from said lens , in which a first equation has said actual diameter ( D P ) as unknown in function of said depth position ( z ), a second equation has said actual length ( L P ) as unknown in function of said depth position ( z ) and a third equation equals the theoretical terminal velocity of said particles to an estimated velocity ( v ) of said particles in function of said depth position ( z ); - wherein said velocity ( v ) of said particles is estimated based on the ratio between a net streak length and an exposure time ( t e ) used to take said at least one first image; - estimating said particles' precipitation rate based on said actual diameter ( D P ) and said velocity ( v ). <EOS>