Live Demonstration: Front and Back Illuminated Dynamic and Active Pixel Vision Sensor Comparison

The demonstration shows the differences between two novel Dynamic and Active Pixel Vision Sensors (DAVIS). While both sensors are based on the same circuits and have the same resolution (346×260), they differ in their manufacturing. The first sensor is a DAVIS with standard Front Side Illuminated (FSI) technology and the second sensor is the first Back Side Illuminated (BSI) DAVIS sensor

In-vivo imaging of neural activity with dynamic vision sensors

Optical recording of neural activity using calcium or voltage indicators requires cameras capable of detecting small temporal contrast in light intensity with sample rates of 10 Hz to 1 kHz. Large pixel scientific CMOS image sensors (sCMOS) are typically used due to their high resolution, high frame rate, and low noise. However, using such sensors for long-term recording is challenging due to their high data rates of up to 1 Gb/s. Here we studied the use of dynamic vision sensor (DVS) event cameras for neural recording. DVS have high dynamic range and a sparse asynchronous output consisting of brightness change events. Using DVS for neural recording could avoid transferring and storing redundant information. We compared the use of a Hamamatsu Orca V2 sCMOS with two advanced DVS sensors (a higher temporal contrast sensitivity 188×180 pixel SDAVIS and a 346×260 pixel higher light sensitivity back-side-illuminated BSIDAVIS) for neural activity recordings with fluorescent calcium indicators both in brain slices and awake mice. The DVS activity responds to the fast dynamics of neural activity, indicating that a sensor combining SDAVIS and BSIDAVIS technologies would be beneficial for long-term in-vivo neural recording using calcium indicators as well as potentially faster voltage indicators

Front and Back Illuminated Dynamic and Active Pixel Vision Sensor Comparison

Back side illumination has become standard image sensor technology owing to its superior quantum efficiency and fill factor. A direct comparison of front and back side illumination (FSI and BSI) used in event-based dynamic and active pixel vision sensors (DAVIS) is interesting because of the potential of BSI to greatly increase the small 20% fill factor of these complex pixels. This brief compares identically designed front and back illuminated DAVIS silicon retina vision sensors. They are compared in term of quantum efficiency (QE), leak activity and modulation transfer function (MTF). The BSI DAVIS achieves a peak QE of 93% compared with the FSI DAVIS, peak QE of 24%, but reduced MTF, due to pixel crosstalk and parasitic photocurrent. Significant “leak events” in the BSI DAVIS limit its use to controlled illumination scenarios without very bright light sources. Effects of parasitic photocurrent and modulation transfer functions with and without IR cut filters are also reported

Color Temporal Contrast Sensitivity in Dynamic Vision Sensors

This paper introduces the first simulations and measurements of event data obtained from the first Dynamic and Active Vision Sensors (DAVIS) with RGBW color filters. The absolute quantum efficiency spectral responses of the RGBW photodiodes were measured, the behavior of the color-sensitive DVS pixels were simulated and measured, and reconstruction through color events interpolation was developed