학술논문

A Hybrid ToF Image Sensor for Long-Range 3D Depth Measurement Under High Ambient Light Conditions
Document Type
Periodical
Source
IEEE Journal of Solid-State Circuits IEEE J. Solid-State Circuits Solid-State Circuits, IEEE Journal of. 58(4):983-992 Apr, 2023
Subject
Components, Circuits, Devices and Systems
Engineered Materials, Dielectrics and Plasmas
Computing and Processing
Logic gates
Pulse measurements
Three-dimensional displays
Image resolution
Distance measurement
Image sensors
Transistors
3D imaging
CMOS depth sensor
direct ToF (dToF)
hybrid ToF (hToF)
indirect ToF (iToF)
interference
multi-tap pixel
time of flight (ToF)
Language
ISSN
0018-9200
1558-173X
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.