Λεξικό .. Burkard spore sampler

The Burkard spore sampler acts on a similar principle to the rotorod sampler, but is used to give a continuous record of particles in the air over the course of several days. It consists of an air-sealed drum that contains a clockwork rotating disc.  which makes a single revolution in 7 days. The surface of this disc is covered with adhesive tape, to trap spores that impact onto it. When the apparatus is assembled, air is sucked into the drum at high speed through a slit orifice by means of a motor at the base of the apparatus.

The particles in this air impact onto a small region of the sticky tape. At the end of a 7-day run, the tape is removed, cut into sections representing hourly or daily periods, then examined microscopically. In this way, it is possible to distinguish clearly between night-released and day-released spores or other particles, and also to relate the types of particle to different weather conditions (e.g. humid or dry periods) while the apparatus was running.

Pollen is a major cause of allergy and monitoring pollen in the air is relevant for diagnostic purposes, development of pollen forecasts, and for biomedical and biological researches. Since counting airborne pollen is a time-consuming task and requires specialized personnel, an automated pollen counting system is desirable. In this article, we present a method for detecting pollen in multifocal optical microscopy images of air samples collected by a Burkard pollen sampler, as a first step in an automated pollen counting procedure. Both color and shape information was used to discriminate pollen grains from other airborne material in the images, such as fungal spores and dirt. A training set of 44 images from successive focal planes (stacks) was used to train the system in recognizing pollen color and for optimization.

The performance of the system has been evaluated using a separate set of 17 image stacks containing 65 pollen grains, of which 86% was detected. The obtained precision of 61% can still be increased in the next step of classifying the different pollen in such a counting system. These results show that the detection of pollen is feasible in images from a pollen sampler collecting ambient air. This first step in automated pollen detection may form a reliable basis for an automated pollen counting system. See Air-sampling methods; Rotorod sampler

References

Landsmeer SH, Hendriks EA, de Weger LA, Reiber JH, Stoel BC. Detection of pollen grains in multifocal optical microscopy images of air samples. Microsc Res Tech. 2009 Jun;72(6):424-30