Patent ID: 9267791
Filing Date: 2016-02-23
CPC Classification: B08B,F24F,G01B,G06T

Claim Text:
1. A system for determining the area of a sash opening in a fume hood formed by at least one movable sash panel mounted over a hood opening to an enclosure structure of the fume hood to reduce the area of the sash opening when the at least one sash panel is moved in one direction or to expand the area of the sash opening when moved in the other direction to provide access to a work surface in the fume hood enclosure space, the system comprising: a emitter and sensor panel mounted in a fume hood enclosure space, the emitter and sensor panel comprising a first light emitter mounted on one side of an image sensor, and a second light emitter mounted on an opposite side of the image sensor, the first and second light emitters configured to illuminate the fume hood enclosure space; a first reflective marker mounted on one edge of the sash opening to reflect light from at least the first light emitter; a second reflective marker mounted on an opposite edge of the sash opening to reflect light from at least the second light emitter, where at least one of the edges of the sash opening with either the first or second reflective marker is formed by an edge of one of the movable sash panels; and a sash position tracking unit configured to determine a distance between the first and second reflective markers based on a distance between a first marker image of the first reflective marker and a second marker image of the second reflective marker in an image detected by the image sensor, where the distance between the first and second reflective markers is used to determine the area of the sash opening and where the image sensor is configured to capture a two-dimensional image divided in pixels, and where the distance between the first and second reflective markers is determined by determining the number of pixels between the first and second marker images, and dividing the number of pixels by a scaling value indicating a number of pixels per unit length.