In spite of the rapid growth in the application of active 3D sensing technologies, it has proved difficult to acquire surface data from transparent objects due to the high transmittance and specularity of the surf aces and the confusion caused by multiple returns. In this paper, we describe how active time-of-flight range sensing using photon counting can be used to acquire data from several transparent surfaces simultaneously. Following a short introduction, the paper is organised in three main sections. First we review the basic principles of time of flight ranging using time correlated single photon counting. Second, we present some basic theory of how data is acquired from multiple surf aces. Third, we present some initial measurements on common transparent objects. Finally, we summarise progress and the necessity for further work.

Time-resolved photoluminescence measurements are taken as a function of bias-voltage for MQW p-i-n diodes with different barrier thicknesses and mesa sizes. The two devices studied had different barrier thicknesses and were on standard S-SEED and L-SEED chips. The former device consists of 60.5 periods of 100 Å GaAs wells and 65 Å Al0.3Ga0.7As barriers whilst the latter consists of 70.5 periods of 100 Å GaAs wells and 35 Å Al0.3Ga0.7As barriers