20110299095 | Shadow Sensing Apparatus - Shadow sensing apparatus for measuring the cross-section and/or position of a tool such as a welding tool at its intersection with a sensor plane, the apparatus having three sensor channels, each comprising a linear array of discrete light sources and a linear light sensor opposite the light sources to receive light emitted therefrom. Each of the channels intersects each other to define a common sensor plane. The light sources are actuatable individually to direct light towards the tool and the respective sensor is arranged to sense the shadow cast thereon by the tool. The cross-section and/or position of the tool or other subject can be determined from up to n×C shadow images, where n is the number of light sources in each of the arrays and C is the number of channels. | 12-08-2011 |