A computer-implemented method of calibrating a camera includes: a. making a video screen display a calibration pattern; b. acquiring from the camera a video stream of a scene comprising said calibration pattern; c. determining a modified calibration pattern depending on the acquired video stream, and making the screen display it; said steps a. to c. being iterated a plurality of times; and then d. estimating intrinsic calibration parameters of the camera by processing the acquired video streams. A computer program product, computer-readable data-storage medium and computer system for carrying out such a method.