The invention discloses a TOF based
ranging system and its
correction method. A main transmitting tube and a transmitting focusing lens group are arranged inside a transmitting lens
barrel. A receiving lens
barrel is in
parallel arrangement with the transmitting lens
barrel; the receiving lens barrel comprises an anti-
stray light structure and a receiving focusing lens group. The anti-
stray light structure is of a conical structure; the big end part of the conical structure's opening is connected with the receiving focusing lens group while the small end part of the opening is provided with an
optical filter. A photosensitive receiving tube and an auxiliary transmitting tube are arranged under the
optical filter and both are welded on a circuit board. During the rapid correction of the
system, the main transmitting tube does not work, and the auxiliary transmitting tube transmits a beam of modulated
infrared light, which is received by the photosensitive receiving tube and is converted into an
electric signal. The internal circuit of the circuit board records the phase different between the modulated
signal and the photosensitive receiving tube received
signal at the time, calculates the
ranging distance error at the time, and stores the
distance error in a storage device. In this manner, the correction process is completed and compensation can be made to each measurement result.