System for determining the shape of particles in motion using an event-based camera

A method for measuring attributes of a particle in motion, the method comprising:

• observing a region of interest with an event-based sensor oriented such that lines of a pixel array of the sensor lie across an expected trajectory of the particle through the region of interest, wherein the event-based sensor comprises pixels that asynchronously generate events in response to changes in brightness;
• defining two reference lines of pixels separated by a spatial distance;
• sampling a first group of events produced by a first of the two reference lines;
• sampling a second group of events produced by a second of the two reference lines;
• determining a temporal distance between the second and first groups of events;
• calculating a longitudinal speed factor of the particle by dividing the spatial distance by the temporal distance, wherein longitudinal refers to a direction perpendicular to the reference lines, wherein the particles have a size spanning multiple adjacent pixels in a line;
• analyzing one of the first and second groups of events over multiple time steps in order to produce an outline of the particle in space-time coordinates including spatial components based on positions of event-triggered pixels in the lines and temporal components based on the time steps;
• and
• converting the space-time coordinates of the outline to spatial coordinates by multiplying the time steps of the space-time coordinates by the longitudinal speed factor to obtain a first spatial coordinate while a second spatial coordinate is derived from the spatial component.