Active ranging method and system

The invention relates to an active ranging method and system. The active ranging method comprises the following steps: S1, projecting a rectangular light spot on a measured object by using a near infrared light source; S2, simultaneously obtaining two imaging images of the surface of the measured object by using a binocular camera with same imaging parameters; S3, positioning the positions of the rectangular light spot in the two imaging images; and S4, determining the distance of the measured object according to a formula described in the specification. According to the active ranging method and system disclosed by the invention, a near-infrared light spot projected by a mini projector is utilized as a calibrator, image mismatch caused by few target features is avoided, the anti-interference performance is high, the ranging accuracy is guaranteed, the contrast of the images obtained by the near infrared light spot is very high, the calibrated light spot imaging position can be obtained by the system by only performing simple scanning processing on the obtained images without extracting and matching the features of the images, and the calculation amount is small, so that the ranging efficiency is high and the real-time performance is very high.