A Time-of-Flight Image Sensor Using 8-Tap P-N Junction Demodulator Pixels
This paper presents a time-of-flight image sensor based on 8-Tap P-N junction demodulator (PND) pixels, which is designed for hybrid-type short-pulse (SP)-based ToF measurements under strong ambient light. The 8-tap demodulator implemented with multiple p-n junctions used for modulating the electric...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-04-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/23/8/3987 |
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| author | Ryosuke Miyazawa Yuya Shirakawa Kamel Mars Keita Yasutomi Keiichiro Kagawa Satoshi Aoyama Shoji Kawahito |
| author_facet | Ryosuke Miyazawa Yuya Shirakawa Kamel Mars Keita Yasutomi Keiichiro Kagawa Satoshi Aoyama Shoji Kawahito |
| author_sort | Ryosuke Miyazawa |
| collection | DOAJ |
| description | This paper presents a time-of-flight image sensor based on 8-Tap P-N junction demodulator (PND) pixels, which is designed for hybrid-type short-pulse (SP)-based ToF measurements under strong ambient light. The 8-tap demodulator implemented with multiple p-n junctions used for modulating the electric potential to transfer photoelectrons to eight charge-sensing nodes and charge drains has an advantage of high-speed demodulation in large photosensitive areas. The ToF image sensor implemented using 0.11 µm CIS technology, consisting of an 120 (H) × 60 (V) image array of the 8-tap PND pixels, successfully works with eight consecutive time-gating windows with the gating width of 10 ns and demonstrates for the first time that long-range (>10 m) ToF measurements under high ambient light are realized using single-frame signals only, which is essential for motion-artifact-free ToF measurements. This paper also presents an improved depth-adaptive time-gating-number assignment (DATA) technique for extending the depth range while having ambient-light canceling capability and a nonlinearity error correction technique. By applying these techniques to the implemented image sensor chip, hybrid-type single-frame ToF measurements with depth precision of maximally 16.4 cm (1.4% of the maximum range) and the maximum non-linearity error of 0.6% for the full-scale depth range of 1.0–11.5 m and operations under direct-sunlight-level ambient light (80 klux) have been realized. The depth linearity achieved in this work is 2.5 times better than that of the state-of-the-art 4-tap hybrid-type ToF image sensor. |
| first_indexed | 2024-03-11T04:33:33Z |
| format | Article |
| id | doaj.art-f6e38193ee7a412a89d91a34434707c7 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-11T04:33:33Z |
| publishDate | 2023-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-f6e38193ee7a412a89d91a34434707c72023-11-17T21:17:29ZengMDPI AGSensors1424-82202023-04-01238398710.3390/s23083987A Time-of-Flight Image Sensor Using 8-Tap P-N Junction Demodulator PixelsRyosuke Miyazawa0Yuya Shirakawa1Kamel Mars2Keita Yasutomi3Keiichiro Kagawa4Satoshi Aoyama5Shoji Kawahito6Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu 432-8011, JapanResearch Institute of Electronics, Shizuoka University, Hamamatsu 432-8011, JapanResearch Institute of Electronics, Shizuoka University, Hamamatsu 432-8011, JapanResearch Institute of Electronics, Shizuoka University, Hamamatsu 432-8011, JapanResearch Institute of Electronics, Shizuoka University, Hamamatsu 432-8011, JapanBrookman Technology, Inc., Hamamatsu 430-0936, JapanResearch Institute of Electronics, Shizuoka University, Hamamatsu 432-8011, JapanThis paper presents a time-of-flight image sensor based on 8-Tap P-N junction demodulator (PND) pixels, which is designed for hybrid-type short-pulse (SP)-based ToF measurements under strong ambient light. The 8-tap demodulator implemented with multiple p-n junctions used for modulating the electric potential to transfer photoelectrons to eight charge-sensing nodes and charge drains has an advantage of high-speed demodulation in large photosensitive areas. The ToF image sensor implemented using 0.11 µm CIS technology, consisting of an 120 (H) × 60 (V) image array of the 8-tap PND pixels, successfully works with eight consecutive time-gating windows with the gating width of 10 ns and demonstrates for the first time that long-range (>10 m) ToF measurements under high ambient light are realized using single-frame signals only, which is essential for motion-artifact-free ToF measurements. This paper also presents an improved depth-adaptive time-gating-number assignment (DATA) technique for extending the depth range while having ambient-light canceling capability and a nonlinearity error correction technique. By applying these techniques to the implemented image sensor chip, hybrid-type single-frame ToF measurements with depth precision of maximally 16.4 cm (1.4% of the maximum range) and the maximum non-linearity error of 0.6% for the full-scale depth range of 1.0–11.5 m and operations under direct-sunlight-level ambient light (80 klux) have been realized. The depth linearity achieved in this work is 2.5 times better than that of the state-of-the-art 4-tap hybrid-type ToF image sensor.https://www.mdpi.com/1424-8220/23/8/3987image sensorPN-junction demodulator (PND)time-of-flight (ToF)depth-adaptive time-gating-number assignment (DATA)depth precision |
| spellingShingle | Ryosuke Miyazawa Yuya Shirakawa Kamel Mars Keita Yasutomi Keiichiro Kagawa Satoshi Aoyama Shoji Kawahito A Time-of-Flight Image Sensor Using 8-Tap P-N Junction Demodulator Pixels Sensors image sensor PN-junction demodulator (PND) time-of-flight (ToF) depth-adaptive time-gating-number assignment (DATA) depth precision |
| title | A Time-of-Flight Image Sensor Using 8-Tap P-N Junction Demodulator Pixels |
| title_full | A Time-of-Flight Image Sensor Using 8-Tap P-N Junction Demodulator Pixels |
| title_fullStr | A Time-of-Flight Image Sensor Using 8-Tap P-N Junction Demodulator Pixels |
| title_full_unstemmed | A Time-of-Flight Image Sensor Using 8-Tap P-N Junction Demodulator Pixels |
| title_short | A Time-of-Flight Image Sensor Using 8-Tap P-N Junction Demodulator Pixels |
| title_sort | time of flight image sensor using 8 tap p n junction demodulator pixels |
| topic | image sensor PN-junction demodulator (PND) time-of-flight (ToF) depth-adaptive time-gating-number assignment (DATA) depth precision |
| url | https://www.mdpi.com/1424-8220/23/8/3987 |
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