An Indirect Time-of-Flight Sensor With Tetra-Pixel Architecture Calibrating Tap Mismatch in a Single Frame

This letter presents an indirect time-of-flight (iToF) sensor with a tetra-pixel architecture to calibrate tap mismatch in a single frame. The proposed tetra-pixel architecture is incorporated with four different tap configurations in 2 by 2 pixels to capture eight essential phase data simultaneously and compensate for the tap mismatch by interpolation. The prototype iToF sensor with a VGA pixel array was fabricated in a 110-nm CIS process and fully characterized. The measured nonlinearity is less than 1.23% at the tetra configuration, achieving about 59% improvement compared with the conventional two-tap architecture. The motion artifact is also greatly suppressed thanks to the single frame capturing.