A 0.13 μm CMOS System-on-Chip for a 512 × 424 Time-of-Flight Image Sensor With Multi-Frequency Photo-Demodulation up to 130 MHz and 2 GS/s ADC

Abstract

We introduce a 512 × 424 time-of-flight (TOF) depth image sensor designed in a TSMC 0.13 μm LP 1P5M CMOS process, suitable for use in Microsoft Kinect for XBOX ONE. The 10 μm × 10 μm pixel incorporates a TOF detector that operates using the quantum efficiency modulation (QEM) technique at high modulation frequencies of up to 130 MHz, achieves a modulation contrast of 67% at 50 MHz and a responsivity of 0.14 A/W at 860 nm. The TOF sensor includes a 2 GS/s 10 bit signal path, which is used for the high ADC bandwidth requirements of the system that requires many ADC conversions per frame. The chip also comprises a clock generation circuit featuring a programmable phase and frequency clock generator with 312.5-ps phase step resolution derived from a 1.6 GHz oscillator. An integrated shutter engine and a programmable digital micro-sequencer allows an extremely flexible multi-gain/multi-shutter and multi-frequency/multi-phase operation. All chip data is transferred using two 4-lane MIPI D-PHY interfaces with a total of 8 Gb/s input/output bandwidth. The reported experimental results demonstrate a wide depth range of operation (0.8-4.2 m), small accuracy error ( 1%), very low depth uncertainty ( 0.5% of actual distance), and very high dynamic range ( 64 dB).

3d Capturing Performances of Low-Cost Range Sensors for Mass-Market Applications

“…Each 10 µm×10 µm pixel incorporates a TOF detector that operates using the Quantum Efficiency Modulation (QEM). This specific technique involves the use of two different modulating frequencies (80MHz and 100 MHz) for solving possible range ambiguities (Bamji et al, 2015;Sell and O'Connor, 2014). The whole Kinect2 2D/3D imaging system is schematically represented in Figure 1b.…”

Application of lidar techniques to time-of-flight range imaging

“…Currently most ToF cameras use four measurements to compute depth, therefore six is realistic for 30 fps of depth information, making it possible to implement SFCW in real-time. The application of lidar techniques to AMCW ToF cameras is possible because of the advances of the ToF imaging arrays, the maximum modulation frequency has increased significantly over the last ten years [4]. The closest previous work using ToF range cameras with multiple modulation frequencies is Kirmani [15], who take complex measurements at five frequencies and resolving multi-path interference with spectrum estimation and phase unwrapping the data.…”

“…Time-of-flight (ToF) imaging based optical metrology has grown significantly in recent years [1][2][3][4][5][6][7][8][9][10]. As the capability of ToF cameras continues to improve more advanced range imaging modalities become increasingly feasible, promising better measurement.…”

“…This technique is known as homodyne amplitude modulated continuous wave (AMCW) ToF range imaging [1]. A key improvement of AMCW ToF range cameras in recent years has been the modulation bandwidth from 20 MHz up to 150 MHz [3,4]. This increase in bandwidth opens the door to new multi-frequency operating modes, including techniques previously restricted to other hardware, that enhance the operation of ToF camera systems.…”

A column-parallel clock skew self-calibration circuit for time-resolved CMOS image sensors

“…Time-resolved (TR) CMOS imagers have recently been paid much attention in applications of time-of-flight range imaging [1,2,3,4], biological imaging [5,6,7], and so on. A state-of-the-art TOF range imager [4] has demonstrated the high range resolution of 0.3 mm, which corresponds to time resolution of 2 ps.…”