Skip to Main content Skip to Navigation
Journal articles

Time-of-Travel Methods for Measuring Optical Flow on Board a Micro Flying Robot

Abstract : For use in autonomous micro air vehicles, visual sensors must not only be small, lightweight and insensitive to light variations; on-board autopilots also require fast and accurate optical flow measurements over a wide range of speeds. Using an auto-adaptive bio-inspired Michaelis–Menten Auto-adaptive Pixel (M2APix) analog silicon retina, in this article, we present comparative tests of two optical flow calculation algorithms operating under lighting conditions from 6×10−7 to 1.6×10−2 W·cm−2 (i.e., from 0.2 to 12,000 lux for human vision). Contrast “time of travel” between two adjacent light-sensitive pixels was determined by thresholding and by cross-correlating the two pixels’ signals, with measurement frequency up to 5 kHz for the 10 local motion sensors of the M2APix sensor. While both algorithms adequately measured optical flow between 25 ∘/s and 1000 ∘/s, thresholding gave rise to a lower precision, especially due to a larger number of outliers at higher speeds. Compared to thresholding, cross-correlation also allowed for a higher rate of optical flow output (99 Hz and 1195 Hz, respectively) but required substantially more computational resources.
Complete list of metadata

Cited literature [41 references]  Display  Hide  Download
Contributor : Reinoud J. Bootsma Connect in order to contact the contributor
Submitted on : Wednesday, April 18, 2018 - 11:25:57 PM
Last modification on : Wednesday, June 8, 2022 - 9:12:02 AM


Sensors (Basel) 2017 Vanhoutte...
Files produced by the author(s)




Erik Vanhoutte, Stefano Mafrica, Franck Ruffier, Reinoud J. Bootsma, Julien Serres. Time-of-Travel Methods for Measuring Optical Flow on Board a Micro Flying Robot. Sensors, MDPI, 2017, 17 (3), pp.571. ⟨10.3390/s17030571⟩. ⟨hal-01551122⟩



Record views


Files downloads