Methods and devices for detecting objects and calculating a time to contact in autonomous driving systems

A method for filtering a plurality of event data, the method comprising:

• emitting towards a scene a transmitted light modulated by a reference signal frequency;
• receiving the plurality of event data, each comprising a change in a light intensity of a pixel, wherein the pixel is part of an image of the scene reflecting the transmitted light;
• determining, for each event data in the plurality of event data, a frequency of the change in the light intensity of the pixel over time;
• identifying a select event data from the plurality of event data based on whether the frequency of the change in the light intensity is substantially the same as the reference signal frequency;
• and
• filtering a filter event data from the plurality of event data based on whether the frequency of the change in the light intensity is not substantially the same as the reference signal frequency.

A device configured to calculate a time to contact for an autonomous vehicle, the device comprising one or more processors configured to:

• obtain a reference signal frequency of a transmitted light that has been modulated by the reference signal frequency and emitted toward a scene;
• obtain a change in a light intensity of at least one pixel, wherein the at least one pixel is part of an image of the scene reflecting the transmitted light;
• determine a frequency of the change in the light intensity of the at least one pixel over time;
• determine an object based on the at least one pixel and based on a comparison between the reference signal frequency and the frequency of the change in the light intensity, wherein the object is defined by a fully enclosed bounding box comprising coordinates of a rectangular border;
• calculate a distance between a set of coordinates of the bounding box closest to the autonomous vehicle and the autonomous vehicle;
• calculate the time to contact between the set of coordinates of the bounding box and the autonomous vehicle;
• and
• control a movement of the autonomous vehicle based on the time to contact.