The state (type, structure and biochemical content or vitality) of natural and agroecosystems are influenced by several factors including available nutrients, soil types, and topographic and climatic factors. In other words, foliar biochemicals (e.g. chlorophyll, Nitrogen) for example may provide information on the factors controlling growth and productivity of ecosystems. However, the quantifi...

3D imaging based on single-photon avalanche diode (SPAD) arrays is of interest in many applications. Limited by the small array size and low fill-factor available SPAD array, it difficult for array-based lidars to achieve high-resolution high-quality images currently. Here, we propose a sub-pixel continuously scanning panoramic method. This method uses increase spatial resolution employs accumu...

The nonlinear distortion introduced by the dead time strongly limits throughput of highly sensitive SPAD-based optical wireless communication (OWC) systems. Optical OFDM can be employed in systems with SPAD arrays to improve spectral efficiency. In this work, a theoretical performance analysis OWC system asymmetrically-clipped (ACO-OFDM) is presented. impact nonlinearity on investigated. additi...

We present a new environmental application of SPAD imagers, namely the continuous and real-time measurement of size and shapes of hydrometeors. Details of the set-up and results obtained with a first 32x32 pixel prototype based on the RADHARD2 chip [1] are illustrated. Real-time operation at very low light levels, 6000 frames per second and 1:100 average data reduction are amongst the most sign...

A monolithic active-quenching and active-reset circuit is presented, designed for avalanche photodiodes that detect single-photons by operating above the breakdown voltage (VB) in a digital mode, known as SPAD's. To the best of our knowledge, this is the first fully-integrated circuit of this kind ever reported. It operates with any existing SPAD, also with very high VB, since the quenching pul...

Nondestructive proximal sensors can be an efficient source of information N status in crops for localized and rapid adjustment fertilization applications. The aim this study was to compare two transmittance/reflectance-based (SPAD, ASD) a florescence-based sensor (Multiplex) their ability measure content corn (Zea mays L.), spring winter barley (Hordeum vulgare rye (Secale cereale both at the l...

A scalable NMOS-only 11T SPAD-based analogue single photon counting pixel is presented. Implemented in advanced 130nm imaging low voltage CMOS, with no extra implants, a state of the art 9.8μm pitch is achieved. Novel pixel operation using a charge transfer amplifier (CTA) allows bias controlled sensitivity from 13.1mV/event to 150μV/event. Less than 2% PRNU is measured in the sensitivity range...

We report on a device capable of imaging second-order spatio-temporal correlations g(x, τ) between photons. The imager is based on a monolithic array of singlephoton avalanche diodes (SPADs) implemented in CMOS technology and a simple algorithm to treat multiphoton time-of-arrival distributions from different SPAD pairs. It is capable of 80 ps temporal resolution with fluxes as low as 10 photon...

Motivated by the need for correct characterization and operation of single-photon avalanche diodes (SPADs), three methods for discriminating between singleand multi-photon triggering in a single CMOS SPAD are compared. The first method, utilizing a measurement of the avalanche’s quench time, correctly distinguishes between avalanches initiated by one photon or 100 incident photons with p > 0.80...