Lenero-Bardallo Juan Antonio, Bryn D H, Hafliger Philipp
IEEE Trans Biomed Circuits Syst. 2014 Jun;8(3):345-57. doi: 10.1109/TBCAS.2013.2271382. Epub 2013 Aug 6.
This article investigates the potential of the first ever prototype of a vision sensor that combines tricolor stacked photo diodes with the bio-inspired asynchronous pixel event communication protocol known as Address Event Representation (AER). The stacked photo diodes are implemented in a 22 × 22 pixel array in a standard STM 90 nm CMOS process. Dynamic range is larger than 60 dB and pixels fill factor is 28%. The pixels employ either simple pulse frequency modulation (PFM) or a Time-to-First-Spike (TFS) mode. A heuristic linear combination of the chip's inherent pseudo colors serves to approximate RGB color representation. Furthermore, the sensor outputs can be processed to represent the radiation in the near infrared (NIR) band without employing external filters, and to color-encode direction of motion due to an asymmetry in the update rates of the different diode layers.
本文研究了首款将三色堆叠光电二极管与受生物启发的异步像素事件通信协议（称为地址事件表示，即AER）相结合的视觉传感器原型的潜力。堆叠光电二极管采用标准STM 90纳米CMOS工艺，以22×22像素阵列实现。动态范围大于60分贝，像素填充因子为28%。像素采用简单脉冲频率调制（PFM）或首次尖峰时间（TFS）模式。芯片固有的伪颜色的启发式线性组合用于近似RGB颜色表示。此外，无需使用外部滤波器，传感器输出即可进行处理，以表示近红外（NIR）波段的辐射，并且由于不同二极管层更新速率的不对称性，还可对运动方向进行颜色编码。
