Skip to main content
Log in

A 256×256 time-of-flight image sensor based on center-tap demodulation pixel structure

  • Research Paper
  • Published:
Science China Information Sciences Aims and scope Submit manuscript

Abstract

This paper proposes a 256 × 256 time-of-flight (TOF) image sensor based on the center-tap (CT) demodulation pixel structure. The image sensor can capture both the two-dimensional (2D) high speed image and the three-dimensional (3D) depth image. The CT pixel consists of two split pinned photodiode (PPD) regions and two pairs of transfer transistors. The transfer transistors adopt a non-uniform doped channel (NUDC) structure, which can increase the electron transfer speed along the transfer channel and eliminate the image lag for high speed imaging. The pixel size is 10 µm × 10 µm, and we design the implementation process of the pixel to increase the electron transfer speed. The sensor is fabricated in a 0.18 µm 1P5M CMOS image sensor process. Test results show that it can capture the 430-fps intensity image and the 90-fps depth image in two different imaging modes. The rectified non-linearity within the 1.0–7.5 m depth measurement range achieves less than 3 cm, and the measurement accuracy achieves 4.0 cm at 2.5 m, corresponding to the relative error of 1.6%.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  1. Zhang W C, Fu Q Y, Wu N J. A programmable vision chip based on multiple levels of parallel processors. IEEE J Solid-State Circ, 2011, 46: 2132–2147

    Article  Google Scholar 

  2. Zhou Y F, Cao Z X, Qin Q, et al. A high speed 1000 fps CMOS image sensor with low noise global shutter pixels. Sci China Inf Sci, 2014, 57: 042405

    Google Scholar 

  3. Shi C, Yang J, Wu N J, et al. A high speed multi-level-parallel array processor for vision chips. Sci China Inf Sci, 2014, 57: 062406

  4. Choi J, Park S, Cho J, et al. A 3.4-µW object-adaptive CMOS image sensor with embedded feature extraction algorithm for motion-triggered object-of-interest imaging. IEEE J Solid-State Circ, 2014, 49: 289–300

    Article  Google Scholar 

  5. Shi C, Yang J, Han Y, et al. A 1000 fps vision chip based on a dynamically reconfigurable hybrid architecture comprising a PE array processor and self-organizing map neural network. IEEE J Solid-State Circ, 2014, 49: 2067–2082

    Article  Google Scholar 

  6. Foix S, Alenya G, Torras C. Lock-in time-of-flight (ToF) cameras: a survey. IEEE Sensors J, 2011, 11: 1917–1926

    Article  Google Scholar 

  7. Remondino F, Stoppa D. TOF Range-Imaging Cameras. Berlin: Springer, 2013

  8. Spirig T, Seitz P, Vietze O, et al. The lock-in CCD-two-dimensional synchronous detection of light. IEEE J Quantum Electron, 1995, 31: 1705–1708

    Article  Google Scholar 

  9. Stoppa D, Massari N, Pancheri L, et al. A range image sensor based on 10-µm lock-in pixels in 0.18-µm CMOS imaging technology. IEEE J Solid-State Circ, 2011, 46: 248–258

    Article  Google Scholar 

  10. Pancheri L, Massari N, Perenzoni M, et al. A QVGA-range image sensor based on buried-channel demodulator pixels in 0.18µm CMOS with extended dynamic range. In: Proceedings of IEEE International Solid-State Circuits Conference Digest of Technical Papers (ISSCC), San Francisco, 2012. 394–396

    Google Scholar 

  11. Lee T Y, Lee Y J, Min D K, et al. A time-of-flight 3-D image sensor with concentric-photogates demodulation pixels. IEEE Trans Electron Devices, 2014, 61: 870–877

    Article  Google Scholar 

  12. Kim S J, Kim J D K, Kang B, et al. A CMOS image sensor based on unified pixel architecture with time-division multiplexing scheme for color and depth image acquisition. IEEE J Solid-State Circ, 2012, 47: 2834–2845

    Article  Google Scholar 

  13. Kim S J, Kang B, Kim J D K, et al. A 1920×1080 3.65µm-pixel 2D/3D image sensor with split and binning pixel structure in 0.11µm standard CMOS. In: Proceedings of IEEE International Solid-State Circuits Conference Digest of Technical Papers (ISSCC), San Francisco, 2012. 396–398

    Google Scholar 

  14. Kim W, Yibing W, Ovsiannikov I, et al. A 1.5Mpixel RGBZ CMOS image sensor for simultaneous color and range image capture. In: Proceedings of IEEE International Solid-State Circuits Conference Digest of Technical Papers (ISSCC), San Francisco, 2012. 392–394

    Google Scholar 

  15. Li Z, Kawahito S, Yasutomi K, et al. A time-resolved CMOS image sensor with draining-only modulation pixels for fluorescence lifetime imaging. IEEE Trans Electron Devices, 2012, 59: 2715–2722

    Article  Google Scholar 

  16. Cao Z X, Zhou Y F, Li Q L, et al. Design of pixel for high speed CMOS image sensors. In: Proceedings of International Image Sensor Workshop, Snowbird, 2013. 229–232

    Google Scholar 

  17. Cao Z X, Li Q L, Han Y, et al. Process techniques of charge transfer time reduction for high speed CMOS image sensors. J Semiconduct, 2014, 35: 114010

    Article  Google Scholar 

  18. Chen Z, Di S, Shi C, et al. A reconfigurable 256 × 256 image sensor controller that is compatible for depth measurement. J Semiconduct, 2014, 35: 105007

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Nanjian Wu.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Chen, Z., Di, S., Cao, Z. et al. A 256×256 time-of-flight image sensor based on center-tap demodulation pixel structure. Sci. China Inf. Sci. 59, 042409 (2016). https://doi.org/10.1007/s11432-015-5453-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1007/s11432-015-5453-0

Keywords

Navigation