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Time-of-flight 3D Cameras

  • Colour-coded Depth and Textured Image
  • Camera Prototype of the QVGA 3D Sensor

The first developments in 3D Vision at SOI were done in the framework of the Opto3D project since year 2000, with the development of an intelligent electro-optical sensor for driving scenarios detection and object recognition [1]. Since then, SOI investigated and developed a number of different operating principles for indirect time-of-flight imaging using CMOS technologies, from the simulation and development of the sensing device, to the integrated circuit and 3D camera system.

Small pixels: 10um pixel pitch

The smallest pixel design in the SOI research unit about 3D sensors exploits a novel device to perform electro-optical demodulation of modulated light. The developed camera prototypes, have a resolution of 80x60 and 160x120 pixels with a record pitch of 10um, the smallest to date [2]. The operating principle is based on the use of modulated light, which allows using near-infrared LED to illuminate the scene. Centimeter resolution in real time has been obtained with the camera prototype.

Large resolution: QVGA with multiple exposure

The SOI research unit demonstrated the scalability of the approach by developing a 320x240-pixel array with 15um pixel pitch [4]. Thanks to the 4 high-speed parallel outputs, the sensor can support multiple exposure and readout in order to increase the dynamic range, covering at 20fps a distance range from 30cm to more than 4m.

A novel approach: avalanche photodiodes gain modulation

Recently, SOI research unit demonstrated the possibility to employ avalanche photodiodes as efficient photodemodulators, by applying a variable bias to modulate their gain. A 64x64-pixel imager and a compact USB prototype camera have been developed, capable to operate as fast as 200fps (3D).


[1] D. Stoppa, L. Viarani, A. Simoni, L. Gonzo, M. Malfatti, G. Pedretti, "A 50x30-pixel CMOS Sensor for TOF-based Real Time 3D Imaging", 2005 Workshop on Charge-Coupled Devices and Advanced Image Sensors, IEEE, 2005, pp. 230-233, Nagano, Japan, 09/06/2005 - 11/06/2005

[2] D. Stoppa, N. Massari, L. Pancheri, M. Malfatti, M. Perenzoni, and L. Gonzo, "An 80x60 Range Image Sensor based on 10um 50MHz Lock-In Pixels in 0.18um CMOS", International Solid-State Circuits Conference ISSCC 2010, San Francisco, 7-11 February, 2010

[3] L. Pancheri, D. Stoppa, N. Massari, M. Malfatti, L. Gonzo, Q. D. Hossain, G.-F. Dalla Betta, "A 160x120 pixel CMOS range image sensor based on current assisted photonic demodulators", SPIE Photonics Europe 2010 - Optical Sensing and Detection, Bruxelles, 2010

[4] L. Pancheri, N. Massari, M. Perenzoni, M. Malfatti, D. Stoppa, "A QVGA-Range Image Sensor Based on Buried-Channel Demodulator Pixels in 0.18μm CMOS with Extended Dynamic Range", International Solid-State Circuits Conference ISSCC 2012, San Francisco, 19-23 February, 2012

[5] O. Shcherbakova, L. Pancheri, G.-F. Dalla Betta, N. Massari, D. Stoppa, "3D Camera based on linear-mode gain-modulated avalanche photodiodes", International Solid-State Circuits Conference ISSCC 2013, San Francisco, 17-21 February, 2013

Application cases: 
  • Automotive: pre-crash warning, driver assistance
  • Ambient-assisted living: monitoring of elderly people
  • Multimedia and gaming: gesture-based user interfaces
  • Industrial control and robotics: three-dimensional positioning
Research topics: