A method for calibrating a measuring system, the system comprising an image capture device, a laser scanner, and a positioning unit, wherein the method comprises preparing at least two images supplied by the image capture device and preparing a 3D point cloud; identifying at least one homologous point in the images and performing an optimization sequence for determining at least one calibration parameter of the measuring system. The sequence comprises at least one iteration of the following steps: for each image, identifying, in the 3D point cloud, at least one close point projecting in a neighborhood of the homologous point of the image; performing a measurement of the distance separating the close points respectively associated with the images; and adjusting the calibration parameter according to the measurement performed.