between the sensory and computing nodes in terms of energy consumption, time delay, and system footprint. [4] To alleviate the issue, in-sensor computing has been proposed that can fuse the data acquisition and computing units within a sensory domain. [5] In-sensor computing enables simultaneous sensing and computing on a single chip, reducing data transportation between the building blocks and minimizing the overall system footprint. However, because sensing, memory, and computing functionalities need to be performed in each pixel, in-sensor computing usually requires complicated backplane circuitry compared to the conventional active-matrix image sensor array that detects and stores optical signals in the two-dimensional (2D) structured pixels. [5] In particular, conventional computing units consist of multiple electronic components to effectively process the acquired signals. The complementary-metal-oxide semiconductor (CMOS) technology-based architectures require more than five transistors even for simple arithmetic computation, [6] which significantly increases the complexity of backplane circuitry for in-sensor computing. [5] Unlike the CMOS architectures that process the signals in the digital domain, emerging neuromorphic computing allows in-memory processing in the analog domain, reducing the energy consumption, data processing time, and footprint of the computing devices. [7][8][9] One key component of neuro morphic computing is a non-volatile memristor (NVM) that can store information as a resistance of the active medium. [10,11] The stored information as an analog form (resistance) is deployable to realize the multiply-accumulate (MAC) operation via Ohm's and Kirchhoff's laws. The general mechanisms of resistive switching are the formation (SET) and rupture (RESET) of metal cations or oxygen vacancies. The stochastic distribution of atomic transitions allows the analog resistive switching of the NVM. [12] Based on NVM as a pixel, the memristor crossbar array can process matrix-form information (images), by using an electrical signal as an input. Such a memristor array architecture can be realized for in-sensor neuromorphic vision computing by employing photo-responsive NVMs. [1,13] However, most of the photo-responsive NVMs feature a three-terminal structure, requiring multiple interconnections and a transport channel for each pixel.In-sensor computing is an emerging architectural paradigm that fuses data acquisition and processing within a sensory domain. The integration of multiple functions into a single domain reduces the system footprint while it minimizes the energy and time for data transfer between sensory and computing units. However, it is challenging for a simple and compact image sensor array to achieve both sensing and computing in each pixel. Here, this work demonstrates a focal plane array with a heterogeneously integrated onephotodiode one-resistor (1P-1R)-based artificial optical neuron that emulates the sensing, computing, and memorization of a biological retina system. This work emp...