Device for measuring the area of the projection of a specimen onto a plane

摘要

The invention relates to a device for measuring the area of the projection of a specimen onto a plane. In this arrangement, a light beam projector is traversed line by line over the specimen at right angles to the projection direction, the traversing device being continuously capable of fixing to the position of the light beam in terms of coordinates. It is established with the aid of a sensor whether the light beam passes the specimen and arrives in the sensor or whether the light beam is interrupted by the specimen. In order to be able to save an additional traversing device for the sensor, the sensor is arranged laterally offset with respect to the projector on the same traversing device and is moved along with the latter. Only a matt projection wall on which the light beam passing by the specimen generates a light spot is arranged on the opposite side. The sensor has a telescopic optical system which is aligned precisely on this light spot and is focused onto it. A plurality of sensors can be arranged around the projector in order for the light spot to be perceptible by at least one of the sensors. Such devices are required in order to determine the drag coefficients of bodies enveloped in a flow such as, e.g., vehicle chassis.