| 摘要 |
Disclosed is a sensor shield (6, 6a,6b) for use in a multi-shelf merchandise display unit (1) including a plurality of sensors (5,5a,5b) mounted on a wall (4) of the unit (1) and opposite a source of illumination (2), in which each sensor (5,5a,5b) corresponds to a single shelf (3,3a,3b) and in which the shelves (3,3a,3b) are at least semi-porous to the illumination. The shield (6, 6a,6b) comprises i) a plate having a length that is sufficient substantially to reduce or prevent incident illumination from the shelf (3,3a,3b) above reaching the sensor (5,5a,5b); and ii) means (26) n to attach the plate to casing of or around the sensor (5,5a,5b) or the wall (4) of the unit (1). The plate is opaque to the illumination detected by the sensor (5,5a,5b). Also disclosed is a method to reduce the interference of light in a multi-shelf merchandise display unit (1) from shelves (3,3a,3b) above a shelf (3,3a,3b) on which stock levels are being measured and a method for monitoring stock levels in a retail display cabinet by measuring light entering the retail display cabinet. |
