A Hybrid Indirect 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 BSI process, can measure the depth up to 20 m in outdoor and under high ambient light of 100 klux. The new hToF operation with overlapped TWs between subframes improves accuracy. The sensor works at 120 fps for a single subframe operation. Interference between multiple ToF cameras in IoT systems is suppressed by a technique of emission cycle-time random modulation.