Infrared presence detector for detecting a presence of an object in a surveillance area

摘要

The present invention relates to a detection device and a method for detecting a presence of an object in a surveillance area. The device comprises at least one infrared radiation sensing element each adapted for generating a sensor signal related to a quantity of infrared radiation received from within the surveillance area by the infrared radiation sensing element, a processing unit and an output means for outputting a determined presence of the object and/or a property derived therefrom. The processing unit is adapted for: obtaining the at least one sensor signal; generating at least one contrast value by comparing the at least one sensor signal to at least one reference value; determining the presence of the object by evaluating a condition on said at least one contrast value; and adjusting the at least one reference value such that negative feedback is applied to the at least one contrast value.

主权项

1. A detection device for detecting a presence of an object in a surveillance area, the device comprising:
at least one infrared radiation sensing element adapted for generating a sensor signal related to a quantity of infrared radiation received from within the surveillance area, a processing unit adapted for: obtaining said sensor signal; generating a contrast value by comparing the obtained sensor signal to a reference value; and determining the presence of the object by evaluating a condition on said contrast value; the processing unit being further adapted for adjusting the reference value such that a negative feedback is applied to the contrast value, and an output means for outputting the determined presence of the object and/or a property derived therefrom,wherein the at least one infrared radiation sensing element comprises at least one thermopile sensor, and in which said processing unit is adapted for:
generating the contrast value by subtracting the reference value from the sensor signal; determining the presence of the object when said contrast value exceeds a predetermined first level; and adjusting the reference value such that the negative feedback is applied to the contrast value by adding a predetermined fraction of the contrast value thereto when said contrast value is below a predetermined second level.