Comparison of structured illumination patterns for positioning

Self-location of devices with a photodetector within an illuminated area can be realised if the illumination comprises a temporal sequence of rapidly displayed illumination patterns. These illumination patterns can be realised by projecting an array of visible light emitting diodes onto the tracking area. We compare 4 different illumination pattern sequences that can be used for this purpose, referred to as sequence A, B, C, and D, respectively. All of these sequences use differential signalling, i.e. the illumination patterns can be grouped in pairs of patterns that are the inverse of each other. For each pattern pair, we experimentally measured the differential signal to noise ratio (SNR) at a certain position and calculated a theoretical figure of merit (FOM) that assesses the susceptibility of this pattern pair to optical cross-talk. File trace_A.txt contains the measured oscilloscope trace of the received optical signal when the photodetector is placed at position (11,8) on a 16x16 spatial positioning grid. The first column is the time in ms and the second column is the received signal in V. File trace_B.txt is the same as file trace_A.txt but for sequence B. File trace_C.txt is the same as file trace_A.txt but for sequence C. File trace_D.txt is the same as file trace_A.txt but for sequence D. File FOM_SNR_A.txt contains the FOM for each pattern pair of sequence A and the experimentally measured differential SNR for this pattern pair. The SNR was obtained by processing the data in trace_A.txt. The first column is the pattern pair number (unitless), the second column is the FOM (unitless), and the third column is the SNR in dB. File FOM_SNR_B.txt is the same as file FOM_SNR_A.txt but for sequence B. File FOM_SNR_C.txt is the same as file FOM_SNR_A.txt but for sequence C. File FOM_SNR_D.txt is the same as file FOM_SNR_A.txt but for sequence D.