In laser measuring scanners, in addition to the ideal output signal, interfering signals occur. They are due to superimposition of diffracted, reflected, scattered, incident, transmitted and interfering light. The proportions between the mentioned components vary in time and also the total intensity distribution changes. Having the above in view, a close analysis of detector signal was carried out. It was proved that for certain beam parameters the intensity distribution pattern depends on the geometry of object and the real dimension of an object can be calculated by introduction of the size dependent correction.