A transfer system for setting a piece in a required orientation, the system comprising: - a vision device (30; 30a, 30b) for capturing at least one image of said piece; - control and command means comprising: a) storage means containing data of stored images representing at least one sample element, which is the same as said piece and is set in respective different stable resting positions; and b) processing means for comparing data of the captured image with the data of the stored images; the system further comprising movement means comprising first rotation means (63; 63a) for rotating said piece about a first axis (57; 57a) and second rotation means (48; 48a) for rotating said piece about a second axis (52; 52a) transverse to said first axis (57; 57a); characterized in that: - the system further comprises a conveyor having a movable horizontal plane for transferring a flow of said pieces; - the control and command means are configured to control said movement means so as to set said piece in the required orientation, as a function of differences between the position of the piece in the captured image and the required orientation, by controlling the rotations about said first and second axes, during a transfer of said piece, in response to the results of the comparisons of the captured and stored images; - said vision device is aimed on said movable horizontal plane, so that said movable horizontal plane defines a resting plane where the pieces are placed on, when the respective images are captured by said vision device. - a vision device (30; 30a, 30b) for capturing at least one image of said piece; - control and command means comprising: a) storage means containing data of stored images representing at least one sample element, which is the same as said piece and is set in respective different stable resting positions; and b) processing means for comparing data of the captured image with the data of the stored images; the system further comprising movement means comprising first rotation means (63; 63a) for rotating said piece about a first axis (57; 57a) and second rotation means (48; 48a) for rotating said piece about a second axis (52; 52a) transverse to said first axis (57; 57a); a) storage means containing data of stored images representing at least one sample element, which is the same as said piece and is set in respective different stable resting positions; and b) processing means for comparing data of the captured image with the data of the stored images; the system further comprising movement means comprising first rotation means (63; 63a) for rotating said piece about a first axis (57; 57a) and second rotation means (48; 48a) for rotating said piece about a second axis (52; 52a) transverse to said first axis (57; 57a); - the system further comprises a conveyor having a movable horizontal plane for transferring a flow of said pieces; - the control and command means are configured to control said movement means so as to set said piece in the required orientation, as a function of differences between the position of the piece in the captured image and the required orientation, by controlling the rotations about said first and second axes, during a transfer of said piece, in response to the results of the comparisons of the captured and stored images; - said vision device is aimed on said movable horizontal plane, so that said movable horizontal plane defines a resting plane where the pieces are placed on, when the respective images are captured by said vision device.