Patent ID: 7624634
Filing Date: 2009-12-01
Classification: G01F

Abstract:
1. An environmental-state determination apparatus comprising: a pair of detection electrodes which provide therebetween a capacitance which changes in accordance with a state of a surrounding environment; first input means for inputting a detection signal to a signal passage connected to the detection electrodes; first capacitance detection means for detecting a first capacitance parameter representing a capacitance of the detection electrodes on the basis of a signal output from the signal passage to which the detection signal is input by the first input means; disconnection means for disconnecting the detection electrodes from the signal passage; second input means for inputting the detection signal to the signal passage from which the detection electrodes are disconnected by the disconnection means; second capacitance detection means for detecting a second capacitance parameter representing a stray capacitance of the signal passage on the basis of a signal output from the signal passage to which the detection signal is input by the second input means; parameter correction means for correcting the first capacitance parameter detected by the first capacitance detection means by subtracting therefrom the second capacitance parameter detected by the second capacitance detection means; and environment determination means for determining the state of the surrounding environment on the basis of the first capacitance parameter corrected by the parameter correction means.