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A coded-exposure-pixel image sensor for computational imaging applications is presented. Each frame exposure time is divided into ${N}$ subframes. Within each subframe, each pixel sorts photo-generated charge into two charge taps depending on that pixel’s 1-bit binary code. ${N}$ global updates of arbitrary pixel-wise codes are implemented in each frame to enable ${N}$ short global pixel-specific subexposures within one frame. To make these subexposures global, two latches per pixel are utilized in a pipelined fashion. The code for the next subframe is loaded into latch 1 in a row parallel fashion, while the code for the current subframe is being applied by latch 2 globally for photo-generated charge sorting during the current subexposure. A $280^{H}\times 176^{V}$ image sensor prototype with $11.2{\text{-}}\mu \text{m}$ pixel pitch has been fabricated in a $0.11{\text{-}}\mu \text{m}$ CMOS image sensor (CIS) technology. The image sensor has been demonstrated in two computational photography applications, each using only a single frame of a video: 1) computing both albedo (a measure of reflectivity) and 3-D depth maps by means of structured-light imaging and 2) computing surface normals (3-D orientations) map by means of photometric stereo imaging. These demonstrations experimentally validate some of the unique capabilities of this computational image sensor, such as accurate 3-D visual scene reconstruction using only one camera, while maintaining its native specifications: the full spatial resolution and the maximum frame rate. [ABSTRACT FROM AUTHOR]

In this paper, a CMOS image sensor based on avalanche photodiodes (APDs) for time-of-flight optical ranging is presented. In-pixel phase-sensitive detection was obtained thanks to the modulation of APD avalanche gain. A pixel based on this principle with 30- \mu \textm pixel pitch and 25.7% fill factor was designed, and a $64 \times 64$ APD image sensor was fabricated in a 0.35- \mu \textm standard CMOS process. The maximum demodulation contrast measured on the array exceeds 85% at 25-MHz modulation frequency. High-frequency modulation was demonstrated on single test pixels, where a demodulation contrast as high as 80% was measured at 200-MHz modulation frequency. A 3-D camera working at a frame rate up to 200 frames/s was realized and characterized. [ABSTRACT FROM AUTHOR]

Indirect Time-of-Flight (I-TOF) cameras can be implemented in a number of ways, each with specific characteristics and performances. In this paper a comprehensive analysis of the implementation possibilities is developed in order to model the main performances with a high level of abstraction. After the extraction of the main characteristics for the high-level model, several figures of merit (FoM) are defined with the purpose of obtaining a common metric: noise equivalent distance, correlated and uncorrelated power responsivity, and background light rejection ratio. The obtained FoMs can be employed for the comparison of different implementations of range cameras based on the I-TOF method: specifically, they are applied for several different sensors developed by the authors in order to compare their performances. [ABSTRACT FROM AUTHOR]

This paper presents the design and electro-optical test of a 160\times120-pixels CMOS sensor specifically conceived for Time-Of-Flight 3D imaging. The in-pixel processing allows the implementation of Indirect Time-Of-Flight technique for distance measurement with reset noise removal through Correlated Double Sampling and embedded fixed-pattern noise reduction, whereas a fast readout operation allows the pixels values to be streamed out at a maximum rate of 10 MSample/s. The imager can operate as a fast 2D camera up to 458 fps, as a 3D camera up to 80 fps, or even coupling both operation modes. The chip has been fabricated using a standard 0.18 \mu\m 1P4M 1.8 V CMOS technology with MIM capacitors. The resulting pixel has a pitch of 29.1 \mu\m with a fill-factor of 34% and includes 66 transistors. Distance measurements up to 4.5 m have been performed with pulsed laser light, achieving a best precision of 10 cm at 1 m in real-time at 55 fps and 175 mA current consumption. [ABSTRACT FROM AUTHOR]