On filtering of laser range data in snowfall

This paper is towards reducing the clutter from snowflakes for outdoor robots. There are three basic cases: 1. normal operation of the laser with objects within range for detection. 2. close range with objects close to the laser i.e. shorter than the pulse length. 3. Free space as background i.e. all detects are false. The findings are summarized as: The two lasers used were a pulsed wide beam laser and a modulated narrow beam laser. The narrow beam laser has much better penetration between the snowflakes. We did not use snow and rain threshold setting for the wide beam laser. Median filtering shows a substantial reduction in snowflake detects. The gamma distribution describes fairly well the distribution of detected snowflakes.