JSSC 2014第10期Image Sensors0.11μm CMOS

A 3-D Camera With Adaptable Background Light Suppression Using Pixel-Binning and Super-Resolution Jihyun Cho, Jaehyuk Choi, Seong-Jin Kim, Seokjun Park, Jungsoon Shin, James D. K. Kim, and Euisik Y oon

提出一种采用列级背景光抑制方案的CMOS TOF 3D相机，适用于高分辨率户外成像。

5.9μm像素间距，24%填充因子，1.47cm-rms时间噪声，1%非线性，100klx背景光抑制

CMOS TOF相机背景光抑制像素合并超分辨率户外成像

▸创新点1：列级背景光抑制方案（方法创新）。通过列级处理而非像素级处理，显著减小了像素尺寸（5.9μm），同时实现了100 klx以上的背景光抑制能力，解决了高分辨率TOF相机在户外强光环境下的性能瓶颈问题。

▸创新点2：像素合并与超分辨率自适应应用（系统创新）。根据场景需求动态切换像素合并模式与超分辨率算法，在保证空间分辨率（24%填充因子）的同时优化背景光抑制效果，实现了0.75-4m范围内仅1%的非线性误差。

▸创新点3：最小化像素间距的电路创新。采用0.11μm CMOS工艺实现5.9μm像素间距（当前TOF相机最小记录），通过优化列级电路布局在有限面积内集成背景光抑制功能，同时维持1.47cm-rms的测距精度。

▸创新点4：混合信号处理架构创新。在12.5MHz解调频率下，通过协同设计模拟前端（背景光抑制）与数字处理（超分辨率），在100ms积分时间内实现2.6cm以下的背景光偏移误差。

Abstract

This paper presents a CMOS time-of- ﬂight (TOF) 3-D camera employing a column-level background light (BGL) suppression scheme for high-resolution outdoor imaging. The use of the column-level approach minimizes a pixel size for high-density pixel arrays. Pixel-binning and super-resolution can be adaptably applied for an optimal BGL suppression at given spatiotemporal resolutions. A p rototype sensor has been fabri- cated by using 0.11 m CMOS processes. The sensor achieved a ﬁll factor of 24% in a pixel pitch of 5.9 m which is the smallest among all the reported TOF came ras up to date. Measurement results showed the temporal noise of 1.47 cm-rms with a 100 ms integration time at a demodulation frequency of 12.5 MHz using a white target at 1 m distance. The non-linearity was measured as 1% over the range of 0.75 m 4 m. The BGL suppression over 100 klx was achieved from indoor and outdoor experiments, while the BGL-induced offset was maintained less than 2.6 cm under 0 100 klx.