Patent ID: 9582116
Date: 2017-02-28
CPC Classifications: G06F

Claim:
1. A method of estimating the position of a radiation blocking object on a surface, the method comprising: providing at least three radiation sensors adjacent to one or more edges of the surface including a first radiation sensor, a second radiation sensor and a third radiation sensor; providing a plurality of radiation sources adjacent to edges of the surface, wherein: establishing a first series of first baseline levels, wherein each first baseline level corresponds to a level of radiation incident on the first sensor when a corresponding one of the radiation sources is activated in the absence of a radiation blocking object; establishing a second series of second baseline levels, wherein each second baseline level corresponds to a level of radiation incident on the second sensor when a corresponding one of the radiation sources is activated in the absence of a radiation blocking object; establishing a third series of third baseline levels, wherein each third baseline level corresponds to a level of radiation incident on the third sensor when a corresponding one of the radiation sources is activated in the absence of a radiation blocking object; assembling a first radiation intensity signal corresponding to the first radiation sensor, wherein the first radiation intensity signal corresponds to a series of first radiation intensity levels, each of the first radiation intensity level corresponding to the intensity of radiation emitted by one of the radiation sources incident on the first radiation sensor in the presence of a radiation blocking object; assembling a second radiation intensity signal corresponding to the second radiation sensor, wherein the second radiation intensity signal corresponds to a series of second radiation intensity levels, each of the second radiation intensity level corresponding to the intensity of radiation emitted by one of the radiation sources incident on the second radiation sensor in the presence of a radiation blocking object; assembling a third radiation intensity signal corresponding to the third radiation sensor, wherein the third radiation intensity signal corresponds to a series of third radiation intensity levels, each of the third radiation intensity level corresponding to the intensity of radiation emitted by one of the radiation sources incident on the third radiation sensor in the presence of a radiation blocking object; identifying a first group of one or more attenuated radiation sources in the first radiation intensity signal by, for at least some of the radiation sources, comparing a corresponding first radiation intensity level with a corresponding first baseline level; identifying a second group of one or more attenuated radiation sources in the second radiation intensity signal by, for at least some of the radiation sources, comparing a corresponding first radiation intensity level with a corresponding first baseline level; identifying a third group of one or more attenuated radiation sources in the third radiation intensity signal by, for at least some of the radiation sources, comparing a corresponding first radiation intensity level with a corresponding first baseline level; and estimating the position of the radiation blocking object based on the position of the first group of attenuated radiation sources relative to first radiation sensor, the position of the second group of attenuated radiation sources relative to the second radiation sensor, and the position of the third group of attenuated radiation sources relative to the third radiation sensor.