High-Linearity High-Resolution Time-of-Flight Linear-Array Digital Image Sensor Using Time-Domain Feedback
This paper presents a high-linearity high-resolution time-of-flight (ToF) linear-array digital image sensor using a time-domain negative feedback technique. A coarse ToF measurement loop uses a 5-bit digital-to-time converter (DTC) and a delayed gating-pulse generator for time-domain feedback to fin...
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MDPI AG
2021-01-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/21/2/454 |
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| author | Juyeong Kim Keita Yasutomi Keiichiro Kagawa Shoji Kawahito |
| author_facet | Juyeong Kim Keita Yasutomi Keiichiro Kagawa Shoji Kawahito |
| author_sort | Juyeong Kim |
| collection | DOAJ |
| description | This paper presents a high-linearity high-resolution time-of-flight (ToF) linear-array digital image sensor using a time-domain negative feedback technique. A coarse ToF measurement loop uses a 5-bit digital-to-time converter (DTC) and a delayed gating-pulse generator for time-domain feedback to find the zero of the difference between ToF and the digital estimate of the gating-pulse delay while maintaining a constant operating point of the analog readout circuits. A fine ToF measurement uses a delta-sigma modulation (DSM) loop using the time-domain feedback with a bit-stream signal form. Because of the self-contained property of the DSM for low distortion and noise exploited by the oversampling signal processing, the proposed technique provides high-linearity and high-range resolution in the fine ToF measurement. A prototype ToF sensor of 16.8 × 16.8 μm<sup>2</sup> two-tap pixels and fabricated in a 0.11 μm (1P4M) CMOS image sensors (CIS) process achieves +0.9%/−0.47% maximum nonlinearity error and a resolution of 0.24 mm (median) for the measurement range of 0–1.05 m. The ToF sensor produces an 11-bit fully digital output with a ToF measurement time of 22.4 ms. |
| first_indexed | 2024-03-09T05:17:35Z |
| format | Article |
| id | doaj.art-d9c8847227654226a660ae14a4bba7be |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-09T05:17:35Z |
| publishDate | 2021-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-d9c8847227654226a660ae14a4bba7be2023-12-03T12:44:47ZengMDPI AGSensors1424-82202021-01-0121245410.3390/s21020454High-Linearity High-Resolution Time-of-Flight Linear-Array Digital Image Sensor Using Time-Domain FeedbackJuyeong Kim0Keita Yasutomi1Keiichiro Kagawa2Shoji Kawahito3Graduate School of Science and Technology, Shizuoka University, Hamamatsu, Shizuoka 432-8011, JapanResearch Institute of Electronics, Shizuoka University, Hamamatsu, Shizuoka 432-8011, JapanGraduate School of Science and Technology, Shizuoka University, Hamamatsu, Shizuoka 432-8011, JapanGraduate School of Science and Technology, Shizuoka University, Hamamatsu, Shizuoka 432-8011, JapanThis paper presents a high-linearity high-resolution time-of-flight (ToF) linear-array digital image sensor using a time-domain negative feedback technique. A coarse ToF measurement loop uses a 5-bit digital-to-time converter (DTC) and a delayed gating-pulse generator for time-domain feedback to find the zero of the difference between ToF and the digital estimate of the gating-pulse delay while maintaining a constant operating point of the analog readout circuits. A fine ToF measurement uses a delta-sigma modulation (DSM) loop using the time-domain feedback with a bit-stream signal form. Because of the self-contained property of the DSM for low distortion and noise exploited by the oversampling signal processing, the proposed technique provides high-linearity and high-range resolution in the fine ToF measurement. A prototype ToF sensor of 16.8 × 16.8 μm<sup>2</sup> two-tap pixels and fabricated in a 0.11 μm (1P4M) CMOS image sensors (CIS) process achieves +0.9%/−0.47% maximum nonlinearity error and a resolution of 0.24 mm (median) for the measurement range of 0–1.05 m. The ToF sensor produces an 11-bit fully digital output with a ToF measurement time of 22.4 ms.https://www.mdpi.com/1424-8220/21/2/454CMOS image sensor (CIS)short-pulsetime-of-flight (ToF)indirect ToFdepth sensing |
| spellingShingle | Juyeong Kim Keita Yasutomi Keiichiro Kagawa Shoji Kawahito High-Linearity High-Resolution Time-of-Flight Linear-Array Digital Image Sensor Using Time-Domain Feedback Sensors CMOS image sensor (CIS) short-pulse time-of-flight (ToF) indirect ToF depth sensing |
| title | High-Linearity High-Resolution Time-of-Flight Linear-Array Digital Image Sensor Using Time-Domain Feedback |
| title_full | High-Linearity High-Resolution Time-of-Flight Linear-Array Digital Image Sensor Using Time-Domain Feedback |
| title_fullStr | High-Linearity High-Resolution Time-of-Flight Linear-Array Digital Image Sensor Using Time-Domain Feedback |
| title_full_unstemmed | High-Linearity High-Resolution Time-of-Flight Linear-Array Digital Image Sensor Using Time-Domain Feedback |
| title_short | High-Linearity High-Resolution Time-of-Flight Linear-Array Digital Image Sensor Using Time-Domain Feedback |
| title_sort | high linearity high resolution time of flight linear array digital image sensor using time domain feedback |
| topic | CMOS image sensor (CIS) short-pulse time-of-flight (ToF) indirect ToF depth sensing |
| url | https://www.mdpi.com/1424-8220/21/2/454 |
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