Since optical wireless power transmission (OWPT) transmits light and generates power at remote targets, determining the position and attitude of the photovoltaic device (PV) from the transmitter is essential before power transmission. PV is robustly detected in various background illuminations utilizing the proposed differential absorption imaging, utilizing the intrinsic nature of PV as a semiconductor. In this method, images are captured using the absorbable and non-absorbable wavelengths of PV, and it is detected from the differential image of these wavelengths. Position estimation was investigated using stereo imagery with a set of conditions implying consistency between images captured by two independent sensors on the left and right. There is a minimum exposure time of the image sensor to ensure that these consistency conditions converge to certain values. It is strongly correlated with the positioning accuracy of the targets and also depends on the attitude angle of the target. Using these features of the minimum exposure time, the position and attitude of the targets were determined even in the case of an incomplete target image. There are diffuse and non-diffuse (specular) options for the reflection of the rear surface of the PV, and positioning accuracy is affected by these reflection characteristics. Experiments were conducted on a 33 × 23-inch optical bench. In the case of a specular target, although positioning accuracy was affected by attitude, its position was estimated within about a 2-inch error in a 20-degree full angular range, while its attitude was estimated within about a 10-15 degree error in a 60-degree full angular range.
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