{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,3]],"date-time":"2026-03-03T16:08:25Z","timestamp":1772554105360,"version":"3.50.1"},"reference-count":23,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2023,11,22]],"date-time":"2023-11-22T00:00:00Z","timestamp":1700611200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"JST, CREST","award":["JPMJCR22C1"],"award-info":[{"award-number":["JPMJCR22C1"]}]},{"name":"JST, CREST","award":["17H06102"],"award-info":[{"award-number":["17H06102"]}]},{"name":"JST, CREST","award":["18H05240"],"award-info":[{"award-number":["18H05240"]}]},{"name":"Grants-in-Aid for Scientific Research (S)","award":["JPMJCR22C1"],"award-info":[{"award-number":["JPMJCR22C1"]}]},{"name":"Grants-in-Aid for Scientific Research (S)","award":["17H06102"],"award-info":[{"award-number":["17H06102"]}]},{"name":"Grants-in-Aid for Scientific Research (S)","award":["18H05240"],"award-info":[{"award-number":["18H05240"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this paper, we present a prototype pseudo-direct time-of-flight (ToF) CMOS image sensor, achieving high distance accuracy, precision, and robustness to multipath interference. An indirect ToF (iToF)-based image sensor, which enables high spatial resolution, is used to acquire temporal compressed signals in the charge domain. Whole received light waveforms, like those acquired with conventional direct ToF (dToF) image sensors, can be obtained after image reconstruction based on compressive sensing. Therefore, this method has the advantages of both dToF and iToF depth image sensors, such as high resolution, high accuracy, immunity to multipath interference, and the absence of motion artifacts. Additionally, two approaches to refine the depth resolution are explained: (1) the introduction of a sub-time window; and (2) oversampling in image reconstruction and quadratic fitting in the depth calculation. Experimental results show the separation of two reflections 40 cm apart under multipath interference conditions and a significant improvement in distance precision down to around 1 cm. Point cloud map videos demonstrate the improvements in depth resolution and accuracy. These results suggest that the proposed method could be a promising approach for virtually implementing dToF imaging suitable for challenging environments with multipath interference.<\/jats:p>","DOI":"10.3390\/s23239332","type":"journal-article","created":{"date-parts":[[2023,11,22]],"date-time":"2023-11-22T10:41:51Z","timestamp":1700649711000},"page":"9332","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Depth Quality Improvement with a 607 MHz Time-Compressive Computational Pseudo-dToF CMOS Image Sensor"],"prefix":"10.3390","volume":"23","author":[{"given":"Anh Ngoc","family":"Pham","sequence":"first","affiliation":[{"name":"Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu 432-8011, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thoriq","family":"Ibrahim","sequence":"additional","affiliation":[{"name":"Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu 432-8011, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Keita","family":"Yasutomi","sequence":"additional","affiliation":[{"name":"Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8011, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shoji","family":"Kawahito","sequence":"additional","affiliation":[{"name":"Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8011, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hajime","family":"Nagahara","sequence":"additional","affiliation":[{"name":"Institute of Datability Science, Osaka University, Suita 565-0871, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Keiichiro","family":"Kagawa","sequence":"additional","affiliation":[{"name":"Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8011, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,11,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Soutschek, S., Penne, J., Hornegger, J., and Kornhuber, J. (2008, January 23\u201328). 3-D gesture-based scene navigation in medical imaging applications using Time-of-Flight cameras. Proceedings of the 2008 IEEE Computer Society Conference on Computer Vision and Pattern Recognition Workshops, Anchorage, AK, USA.","DOI":"10.1109\/CVPRW.2008.4563162"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Uebersax, D., Gall, J., Van den Bergh, M., and Van Gool, L. (2011, January 6\u201313). Real-time sign language letter and word recognition from depth data. Proceedings of the 2011 IEEE International Conference on Computer Vision Workshops (ICCV Workshops), Barcelona, Spain.","DOI":"10.1109\/ICCVW.2011.6130267"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Van den Bergh, M., and Van Gool, L. (2011, January 5\u20137). Combining RGB and ToF cameras for real-time 3D hand gesture interaction. Proceedings of the 2011 IEEE Workshop on Applications of Computer Vision (WACV), Kona, HI, USA.","DOI":"10.1109\/WACV.2011.5711485"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1049\/iet-cvi.2017.0052","article-title":"Review of constraints on vision-based gesture recognition for human\u2013computer interaction","volume":"12","author":"Chakraborty","year":"2018","journal-title":"IET Comput. Vis."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1016\/j.visinf.2017.01.008","article-title":"Recent advances in transient imaging: A computer graphics and vision perspective","volume":"1","author":"Jarabo","year":"2017","journal-title":"Vis. Inform."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Bhandari, A., Kadambi, A., Whyte, R., Barsi, C., Feigin, M., Dorrington, A., and Raskar, R. (2014). Resolving multipath interference in time-of-flight imaging via modulation frequency diversity and sparse regularization. Opt. Lett., 39.","DOI":"10.1364\/OL.39.001705"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1847","DOI":"10.1109\/JSSC.2005.848173","article-title":"Design and characterization of a CMOS 3-D image sensor based on single photon avalanche diodes","volume":"40","author":"Niclass","year":"2005","journal-title":"IEEE J. Solid-State Circuits"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Ximenes, A.R., Padmanabhan, P., Lee, M.-J., Yamashita, Y., Yaung, D.N., and Charbon, E. (2018, January 11\u201315). A 256 \u00d7 256 45\/65 nm 3D-stacked SPAD-based direct TOF image sensor for LiDAR applications with optical polar modulation for up to 18.6 dB interference suppression. Proceedings of the 2018 IEEE International Solid\u2014State Circuits Conference\u2014(ISSCC), San Francisco, CA, USA.","DOI":"10.1109\/ISSCC.2018.8310201"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Remondino, F., and Stoppa, D. (2013). TOF Range-Imaging Cameras, Springer.","DOI":"10.1007\/978-3-642-27523-4"},{"key":"ref_10","unstructured":"Lindner, M., and Kolb, A. (2009). Dynamic 3D Imaging, Springer."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Pham, A.N., Thoriq, I., Yasutomi, K., Kawahito, S., Nagahara, H., and Kagawa, K. (2023, January 21\u201325). A 607 MHz time-compressive computational pseudo-dToF CMOS image sensor. Proceedings of the 2023 International Image Sensor Workshop, Edinburgh, UK.","DOI":"10.3390\/s23239332"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Keel, M.-S., Kim, D., Kim, Y., Bae, M., Ki, M., Chung, B., Son, S., Lee, H., Jo, H., and Shin, S.-C. (2021, January 13\u201322). 7.1 A 4-tap 3.5 \u03bcm 1.2 Mpixel Indirect Time-of-Flight CMOS Image Sensor with Peak Current Mitigation and Multi-User Interference Cancellation. Proceedings of the 2021 IEEE International Solid-State Circuits Conference (ISSCC), San Francisco, CA, USA.","DOI":"10.1109\/ISSCC42613.2021.9365854"},{"key":"ref_13","unstructured":"Stoppa, D., Massari, N., Pancheri, L., Malfatti, M., Perenzoni, M., and Gonzo, L. (2010, January 7\u201311). An 80 \u00d7 60 range image sensor based on 10 \u03bcm 50 MHz lock-in pixels in 0.18 \u03bcm CMOS. Proceedings of the 2010 IEEE International Solid-State Circuits Conference\u2014(ISSCC), San Francisco, CA, USA."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Mochizuki, F., Kagawa, K., Okihara S-i Seo, M.-W., Zhang, B., Takasawa, T., Yasutomi, K., and Kawahito, S. (2015, January 2\u201326). 6.4 Single-shot 200 Mfps 5 \u00d7 3-aperture compressive CMOS imager. Proceedings of the 2015 IEEE International Solid-State Circuits Conference\u2014(ISSCC) Digest of Technical Papers, San Francisco, CA, USA.","DOI":"10.1109\/ISSCC.2015.7062953"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Mochizuki, F., Kagawa, K., Okihara S-i Seo, M.-W., Zhang, B., Takasawa, T., Yasutomi, K., and Kawahito, S. (2016). Single-event transient imaging with an ultra-high-speed temporally compressive multi-aperture CMOS image sensor. Opt. Express, 24.","DOI":"10.1364\/OE.24.004155"},{"key":"ref_16","unstructured":"Kagawa, K., Kokado, T., Sato, Y., Mochizuki, F., Nagahara, H., Takasawa, T., Yasutomi, K., and Kawahito, S. (2019, January 24\u201327). Multi-tap macro-pixel based compressive ultra-high-speed CMOS image sensor. Proceedings of the 2019 International Image Sensor Workshop, Snowbird, UT, USA."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"5656","DOI":"10.1109\/JSEN.2020.3038487","article-title":"Data Processing Approaches on SPAD-Based d-TOF LiDAR Systems: A Review","volume":"21","author":"Chen","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Kumagai, O., Ohmachi, J., Matsumura, M., Yagi, S., Tayu, K., Amagawa, K., Matsukawa, T., Ozawa, O., Hirono, D., and Shinozuka, Y. (2021, January 13\u201322). 7.3 A 189 \u00d7 600 Back-Illuminated Stacked SPAD Direct Time-of-Flight Depth Sensor for Automotive LiDAR Systems. Proceedings of the 2021 IEEE International Solid-State Circuits Conference (ISSCC), San Francisco, CA, USA.","DOI":"10.1109\/ISSCC42613.2021.9365961"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Kagawa, K., Horio, M., Pham, A.N., Ibrahim, T., Okihara S-i Furuhashi, T., Takasawa, T., Yasutomi, K., Kawahito, S., and Nagahara, H. (2022). A Dual-Mode 303-Megaframes-per-Second Charge-Domain Time-Compressive Computational CMOS Image Sensor. Sensors, 22.","DOI":"10.3390\/s22051953"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1109\/MSP.2007.4286571","article-title":"Compressive Sensing [Lecture Notes]","volume":"24","author":"Baraniuk","year":"2007","journal-title":"IEEE Signal Process. Mag."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"443","DOI":"10.1109\/JCN.2013.000083","article-title":"Compressive sensing: From theory to applications, a survey","volume":"15","author":"Qaisar","year":"2013","journal-title":"J. Commun. Netw."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"507","DOI":"10.1007\/s10589-013-9576-1","article-title":"An efficient augmented Lagrangian method with applications to total variation minimization","volume":"56","author":"Li","year":"2013","journal-title":"Comput. Optim. Appl."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Bamji, C.S., Mehta, S., Thompson, B., Elkhatib, T., Wurster, S., Akkaya, O., Payne, A., Godbaz, J., Fenton, M., and Rajasekaran, V. (2018, January 11\u201315). IMpixel 65 nm BSI 320 MHz demodulated TOF Image sensor with 3 \u03bcm global shutter pixels and analog binning. Proceedings of the 2018 IEEE International Solid\u2014State Circuits Conference\u2014(ISSCC), San Francisco, CA, USA.","DOI":"10.1109\/ISSCC.2018.8310200"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/23\/9332\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T21:27:25Z","timestamp":1760131645000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/23\/9332"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,11,22]]},"references-count":23,"journal-issue":{"issue":"23","published-online":{"date-parts":[[2023,12]]}},"alternative-id":["s23239332"],"URL":"https:\/\/doi.org\/10.3390\/s23239332","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,11,22]]}}}