A CAPD based time-of-flight ranging pixel with wide dynamic range

2008 ◽  
Author(s):  
Daniel Van Nieuwenhove ◽  
Ward Van der Tempel ◽  
Riemer Grootjans ◽  
Maarten Kuijk
Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5464 ◽  
Author(s):  
Preethi Padmanabhan ◽  
Chao Zhang ◽  
Edoardo Charbon

Direct time-of-flight (DTOF) is a prominent depth sensing method in light detection and ranging (LiDAR) applications. Single-photon avalanche diode (SPAD) arrays integrated in DTOF sensors have demonstrated excellent ranging and 3D imaging capabilities, making them promising candidates for LiDARs. However, high background noise due to solar exposure limits their performance and degrades the signal-to-background noise ratio (SBR). Noise-filtering techniques based on coincidence detection and time-gating have been implemented to mitigate this challenge but 3D imaging of a wide dynamic range scene is an ongoing issue. In this paper, we propose a coincidence-based DTOF sensor architecture to address the aforementioned challenges. The architecture is analyzed using a probabilistic model and simulation. A flash LiDAR setup is simulated with typical operating conditions of a wide angle field-of-view (FOV = 40 ° ) in a 50 klux ambient light assumption. Single-point ranging simulations are obtained for distances up to 150 m using the DTOF model. An activity-dependent coincidence is proposed as a way to improve imaging of wide dynamic range targets. An example scene with targets ranging between 8–60% reflectivity is used to simulate the proposed method. The model predicts that a single threshold cannot yield an accurate reconstruction and a higher (lower) reflective target requires a higher (lower) coincidence threshold. Further, a pixel-clustering scheme is introduced, capable of providing multiple simultaneous timing information as a means to enhance throughput and reduce timing uncertainty. Example scenes are reconstructed to distinguish up to 4 distinct target peaks simulated with a resolution of 500 ps. Alternatively, a time-gating mode is simulated where in the DTOF sensor performs target-selective ranging. Simulation results show reconstruction of a 10% reflective target at 20 m in the presence of a retro-reflective equivalent with a 60% reflectivity at 5 m within the same FOV.


2001 ◽  
Vol 36 (8) ◽  
pp. 1228-1238 ◽  
Author(s):  
T. Ruotsalainen ◽  
P. Palojarvi ◽  
J. Kostamovaara

2021 ◽  
pp. 1-1
Author(s):  
Sami Kurtti ◽  
Aram Baharmast ◽  
Jussi-Pekka Jansson ◽  
Juha Kostamovaara

Author(s):  
F. Ouyang ◽  
D. A. Ray ◽  
O. L. Krivanek

Electron backscattering Kikuchi diffraction patterns (BKDP) reveal useful information about the structure and orientation of crystals under study. With the well focused electron beam in a scanning electron microscope (SEM), one can use BKDP as a microanalysis tool. BKDPs have been recorded in SEMs using a phosphor screen coupled to an intensified TV camera through a lens system, and by photographic negatives. With the development of fiber-optically coupled slow scan CCD (SSC) cameras for electron beam imaging, one can take advantage of their high sensitivity and wide dynamic range for observing BKDP in SEM.We have used the Gatan 690 SSC camera to observe backscattering patterns in a JEOL JSM-840A SEM. The CCD sensor has an active area of 13.25 mm × 8.83 mm and 576 × 384 pixels. The camera head, which consists of a single crystal YAG scintillator fiber optically coupled to the CCD chip, is located inside the SEM specimen chamber. The whole camera head is cooled to about -30°C by a Peltier cooler, which permits long integration times (up to 100 seconds).


2020 ◽  
Vol 13 (5) ◽  
pp. 1085-1093
Author(s):  
XU Da ◽  
◽  
YUE Shi-xin ◽  
ZHANG Guo-yu ◽  
SUN Gao-fei ◽  
...  

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