Compact Numerical Modeling of Indirect Time-of-Flight CMOS Image Sensors

Hu, Congzhen; Zhang, Bing; Xin, Youze; Li, Dan; Guo, Zhuoqi; Xue, Zhongming; Ke, Zungui; Geng, Li

doi:10.1109/ted.2022.3218497

Cited by 3 publications

(3 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Namely electrical variations are mismatches in the transfer gate threshold voltages or the biasing between pixels. 3,4 It is shown in Fig. 4b that all parasitic charges are collected directly after the optical generation impulse.…”

Section: Pixel Response and Depth Non-uniformitymentioning

confidence: 99%

“…Extensive simulation work and modeling have been done to understand and improve Indirect time of flight (iToF) pixels accuracy. [1][2][3] iToF is a depth sensing technique that consists of emitting an optical signal modulated in intensity with a continuous wave, for example a sinus wave with frequencies ranging from 10M Hz to 250M Hz. [4][5][6] An electrical reference of the emitted optical sinus signal is stored.…”

Section: Introductionmentioning

confidence: 99%

“…When this operation is executed between successive frames, it is possible to compensate for the sampling limitations of a single simpler pixel with fewer sensing nodes. 3,9 Essentially, multiple pixels operate artificially as one with fewer taps to give a more precise depth measurement.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Indirect time-of-flight pixel study: 3D Monte Carlo simulation approach

Lopes,

Fonteneau,

Rideau

et al. 2024

Physics and Simulation of Optoelectronic Devices XXXII

View full text Add to dashboard Cite

The use of 3D Monte Carlo simulations for the study of an indirect time of flight (iToF) pixel revealed underlying information compared to conventional simulation tools. Experimental tendencies and results are systematically compared with results obtained numerically. During the sensor operation, iToF pixels reconstruct the depth information using an optical signal modulated in intensity at high operation frequencies of hundreds of MHz. A demodulation operation samples the photogenerated charges at different times in a single pixel. An efficient transfer is dependent of the charge carrier path in the pixel volume.Through the coupling of 3D Monte Carlo with a commercial Poisson solver and optical simulation tools, a complete and accurate simulation methodology was developed allowing the estimation of iToF main figures of merit such as demodulation contrast, parasitic light sensitivity and quantum efficiency. The method consists of generating a light impulse and studying the distribution and collection of each unitary charge in time through MC simulations. Detailed information can be obtained in the 3D volume of a pixel for the photogenerated carriers. The efficiency of charges transfer from the pixel volume to sensing nodes is given at the operation frequency by the demodulation contrast. The electrostatic potential barriers reducing the transfer efficiency can be easily identified and lost photogenerated carriers can be estimated. The prediction accuracy of Monte Carlo simulation is further improved through the coupling of photogeneration and electron mobility profiles extracted from optical simulation and drift-diffusion-based-technology computed-aided design tools respectively. A non optimized small pitch pixel was optimized thanks to these advanced multi-physics simulations.

show abstract

Section: Pixel Response and Depth Non-uniformitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Indirect time-of-flight pixel study: 3D Monte Carlo simulation approach

Lopes,

Fonteneau,

Rideau

et al. 2024

Physics and Simulation of Optoelectronic Devices XXXII

View full text Add to dashboard Cite

show abstract

A Backside-Illuminated 3.5 μm Pixel With 86% Demodulation Contrast at 1.0 V Voltage Swing for Indirect Time-of-Flight Image Sensors

Zhang

Xin

et al. 2023

IEEE Trans. Electron Devices

View full text Add to dashboard Cite

Wiggling-Related Error Correction Method for Indirect ToF Imaging Systems

et al. 2023

View full text Add to dashboard Cite

Indirect time-of-flight (ToF) imaging systems enable a broad array of applications owing to their high frame rate, strong durability, and low cost. However, the wiggling-related error caused by the harmonics in the emitted signal significantly affects the range accuracy of indirect ToF imaging systems. In this paper, we establish a mathematical model of the wiggling-related error and propose a wiggling-related error correction method for indirect ToF imaging systems. This method adds a delay measurement and utilizes raw intensity measurements to evaluate the system state based on an adaptive Kalman filter (AKF), which is easy to implement in most indirect ToF imaging systems. Simulation and experimental results show that the proposed method performed well in reducing the wiggling-related error and had good robustness in different integration times. Compared with the existing methods, the proposed method not only has better performance but also is easier to implement. We believe that this study provides effective guidance for researchers understanding the wiggling-related error and a potential direction for the accuracy improvement of indirect ToF imaging systems.

show abstract

Compact Numerical Modeling of Indirect Time-of-Flight CMOS Image Sensors

Cited by 3 publications

References 19 publications

Indirect time-of-flight pixel study: 3D Monte Carlo simulation approach

Indirect time-of-flight pixel study: 3D Monte Carlo simulation approach

A Backside-Illuminated 3.5 μm Pixel With 86% Demodulation Contrast at 1.0 V Voltage Swing for Indirect Time-of-Flight Image Sensors

Wiggling-Related Error Correction Method for Indirect ToF Imaging Systems

Contact Info

Product

Resources

About