A Hybrid ToF Image Sensor for Long-Range 3D Depth Measurement Under High Ambient Light Conditions
Kunihiro Hatakeyama, Yu Okubo, Tomohiro Nakagome, Masahiro Makino, Hiroshi Takashima, Takahiro Akutsu, Takehide Sawamoto, Masanori Nagase, Tatsuo NOGUCHI, Shoji Kawahito
Abstract
A new indirect time of flight (iToF) sensor realizing long-range measurement of 30 m has been demonstrated by a hybrid ToF (hToF) operation, which uses multiple time windows (TWs) prepared by multi-tap pixels and range-shifted subframes. The VGA-resolution hToF image sensor with 4-tap and 1-drain pixels, fabricated by the BSI process, can measure a depth of up to 30 m for indoor operation and 20 m for outdoor operation under high ambient light of 100 klux. The new hToF operation with overlapped TWs between subframes for mitigating an issue on the motion artifact is implemented. The sensor works at 120 frames/s for a single subframe operation. Interference between multiple ToF cameras in IoT systems is suppressed by a technique of emission cycle-time changing.