Ranging method, device, equipment and medium

The invention discloses a distance measuring method, device and equipment and a medium. The method comprises the following steps: acquiring a first image of a to-be-measured object at a first calibration position within the field depth range of a telecentric lens; acquiring a second image of the to-be-measured object at the second calibration position; acquiring a third image of the to-be-measured object at the third calibration position; respectively acquiring a difference value between the first image and the second image and a difference value between the first image and the third image to obtain a first gray difference value image and a second gray difference value image; and substituting the first gray difference image and the second gray difference image into a preset nonlinear polynomial model to obtain the distance from the to-be-measured object to the surface of one side, close to the to-be-measured object, of the telecentric lens. According to the method, the images of the to-be-measured object at d