Calibration of and stereo measurements from two synchronized event cameras

This repository contains files related to the left camera (Gen4.1 sensor in the Prophesee's Evaluation Kit 2) and right camera (IMX636 ES sensor in Prophesee's Evaluation Kit 4) of a stereo setup of two event cameras. The event cameras were synchronized electronically such that time stamps in both event streams were produced by synchronized clocks. The raw files can be viewed and analyzed using Prophesee's Metavision Studio or any of the other tools provided in the Metavision SDK. A projector produces two different levels of illumination with a sharp transition making up a scanning contrast edge. This contrast edge moves through the measurement volume in order to sample the surfaces of the scene and sequentially trigger corresponding events in both event cameras.

Calibration data

Calibration data of the stereo setup of event cameras is contained in the files left_recorded_patterns.json and right_recorded_patterns.json, which were recorded based on the metavision mono calibration recording tool. These files contain a common description of the employed checkerboard pattern in the form of 3D points of the corners (JSON field "pattern_3d") which are all assumed to lie in the same plane. The grid distances along the edges of the pattern ("square_width" and "square_height") provide scaling to the calibration. Lists of 2D positions of identified corners are found in the field "pts_2d". Each list corresponds to the checkerboard pattern as observed by the stereo setup from a different pose. The order of poses is the same in both calibration files.

Stereo measurements

Raw event streams of both event cameras of different scenes sampled by a projector are saved in the contrast_series and object_series subdirectories. For each measurement there is a '...left.csv' and a '...right.csv' file which are the temporally synchronized event streams of a single measurement. Furthermore, there is a '...params.json' file for each measurement. They contain the upper and lower levels of illuminance that the projector produces, measured at the center of the measurement volume. Additionaly, they contain the bias parameters for the cameras used in each measurement. There is also a ground truth point cloud of the stairs object ('objectseries/stairs_ground_truth.asc') reconstructed from measurements of a different 3D sensor. The contrast series contains measurements of a plane object measured with different contrasts of the scanning contrast edge. There are five repetitions for each contrast. The object series contains single measurements of multiple objects.