A hybrid event-based pixel for low-power image Sensing

authors

• Akrarai Mohamed
• Margotat Nils
• Sicard Gilles
• Fesquet Laurent

keywords

• Dynamic vision sensor pixel
• Event based techniques
• Time to first spike pixel

abstract

This article presents a hybrid pixel dedicated to event-based image sensors, which suppresses spatial and temporal redundancies. This pixel is a combination between two kinds of pixels, known as TFS and DVS. The first one is able to reduce - associated to a dedicated readout - spatial redundancies, while the second manages the temporal redundancies. Each pixel is classically built with a photodiode but this hybrid structure shares the photodiode between the DVS and the TFS pixels. In our design, 4 TFS pixel photodiodes are shared with 1 DVS pixel, which exploits the average current of the latter. In order to evaluate such a pixel, a comparison is made between a hybrid pixel matrix and a matrix composed of TFS and DVS pixels. The evaluation is made in terms of activity and power but also by analyzing their fill-factor, circuitry and layout. A testchip including the 2 event-based image sensors has been designed in FDSOI 28 nm technology from STMicroelecronics.

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