Single-photon pulsed-light indirect time-of-flight 3D ranging

Bellisai, S.; Bronzi, Danilo; Villa, Federica; Tisa, Simone; Tosi, Alberto; Zappa, Franco

doi:10.1364/oe.21.005086

Cited by 32 publications

(19 citation statements)

References 10 publications

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“…Integrating an array of SPAD detectors onto a single CMOS chip and using high precision laser illuminators allows the development of SPAD cameras, which can capture high-speed 3D images under extremely low-light conditions. SPAD array cameras have a broad range of applications from military, meteorology, space, augmented reality, remote sensing, autonomous robotics [2] [3]. SPAD imagers can operate in two distinct modes.…”

Section: A Single Phone Avalanche Diodes Sensormentioning

confidence: 99%

Event-Based Processing of Single Photon Avalanche Diode Sensors

Afshar

Hamilton

Davis³

et al. 2020

IEEE Sensors J.

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Single Photon Avalanche Diode sensor arrays operating in direct time of flight mode can perform 3D imaging using pulsed lasers. Operating at high frame rates, SPAD imagers typically generate large volumes of noisy and largely redundant spatio-temporal data. This results in communication bottlenecks and unnecessary data processing. In this work, we propose a set of neuromorphic processing solutions to this problem. By processing the SPAD generated spatio-temporal patterns locally and in an event-based manner, the proposed methods reduce the size of output data transmitted from the sensor by orders of magnitude while increasing the utility of the output data in the context of challenging recognition tasks. To demonstrate these results, the first large scale complex SPAD imaging dataset is presented involving high-speed view-invariant recognition of airplanes with background clutter. The framebased SPAD imaging dataset is converted via several alternative methods into event-based data streams and processed using a range of feature extractor networks and pooling methods. The results of the event-based processing methods are compared to processing the original frame-based dataset via frame-based but otherwise identical architectures. The results show the eventbased methods are superior to the frame-based approach both in terms of classification accuracy and output data-rate.

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Section: A Single Phone Avalanche Diodes Sensormentioning

confidence: 99%

Event-Based Processing of Single Photon Avalanche Diode Sensors

Afshar

Hamilton

Davis³

et al. 2020

IEEE Sensors J.

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show abstract

“…Indeed, the 64×32 SPAD array is designed for measuring the distance of an object in front of the camera, exploiting the indirect time-of-flight approach (see Ref. [4] for more details on this technique). It processes at the pixel-level intensity and, with an external illuminator, depth-ranging information through indirect Time-of-Flight (iTOF) measurement, by using either continuous-wave (CW) or pulsed light modulation.…”

Section: ×32 Spad Arraymentioning

confidence: 99%

“…The up 9-bit counter integrates the background light, thus storing 2D intensity information of the scene. The two up/down 9-bit counters are bidirectional and perform light demodulation for either pulsed-or CW-iTOF calculation [4]. Figure 4 shows a simplified block diagram of the pixel.…”

Section: ×32 Spad Arraymentioning

confidence: 99%

Low-noise CMOS SPAD arrays with in-pixel time-to-digital converters

et al. 2014

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We present our latest results concerning CMOS Single-Photon Avalanche Diode (SPAD) arrays for high-throughput parallel single-photon counting. We exploited a high-voltage 0.35 μm CMOS technology in order to develop low-noise CMOS SPADs. The Dark Count Rate is 30 cps at room temperature for 30 μm devices, increases to 2 kcps for 100 μm SPADs and just to 100 kcps for 500 μm ones. Afterpulsing is less than 1% for hold-off time longer than 50 ns, thus allowing to reach high count rates. Photon Detection Efficiency is > 50% at 420 nm, > 40% below 500 nm and is still 5% at 850 nm. Timing jitter is less than 100 ps (FWHM) in SPADs with active area diameter up to 50 μm. We developed CMOS SPAD imagers with 150 μm pixel pitch and 30 μm SPADs. A 64×32 SPAD array is based on pixels including three 9-bit counters for smart phase-resolved photon counting up to 100 kfps. A 32x32 SPAD array includes 1024 10-bit Time-to-Digital Converters (TDC) with 300 ps resolution and 450 ps single-shot precision, for 3D ranging and FLIM. We developed also linear arrays with up to 60 pixels (with 100 μm SPAD, 150 μm pitch and in-pixel 250 ps TDC) for time-resolved parallel spectroscopy with high fill factor

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“…Due to the use of artificial light, however, the captured image tends to have unwanted artifacts including red eyes, distracting shadows, and specularities. 6,7 A ToF depth camera emits modulated infrared (IR) light to the scene and measures a depth value for each pixel using the phase delay between the emitted and received IR light signals. 1,2 These approaches attempt to produce an image that contains large-scale and detail information extracted from nonflashed and flashed images, respectively.…”

Section: Introductionmentioning

confidence: 99%

Color image enhancement using depth and intensity measurements of a time-of-flight depth camera

Jung

Choi

2013

Opt. Eng

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A time-of-flight (ToF) depth camera can capture a depth map of the scene by measuring the phase delay between the emitted and reflected infrared (IR) light signals. In addition, an intensity map that represents the magnitude of the reflected light can be obtained by the ToF camera. If we consider the light source of the ToF camera as a flash, the intensity map can be deemed as an IR flashed image. Building on ideas from flash/no-flash photography and dark flash photography, we devise a color image enhancement framework that exploits information from the intensity and depth maps. To this end, ToF-related distortions of the intensity and depth maps are first reduced. We then restore fine details of color images captured under weak illumination by combining mutually beneficial information from the visible and IR band signals. In addition, we show that the depth map can be used to produce depth-adaptive effects such as depth-adaptive smoothing at the resultant color image.

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Single-photon pulsed-light indirect time-of-flight 3D ranging

Cited by 32 publications

References 10 publications

Event-Based Processing of Single Photon Avalanche Diode Sensors

Event-Based Processing of Single Photon Avalanche Diode Sensors

Low-noise CMOS SPAD arrays with in-pixel time-to-digital converters

Color image enhancement using depth and intensity measurements of a time-of-flight depth camera

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