A method for estimating values for a set of parameters of an imaging system is presented. At least two pictures having an overlapping area are taken with the imaging system from different positions. Pulses are sent out to the area, the reflected pulses are detected and distances between a sender of the pulses and the respective point where the pulses were reflected are calculated based on the travel time of the pulses. First information about the area is calculated based on the pictures. Second information related to the calculated distances to the area is also calculated. Values for quantities contained in the first and second information are compared. If the value for a quantity obtained from the first information differs from the value obtained from the second information, values and/or an error estimate for the set of parameters of the imaging system is calculated based on the difference.