A method for detecting the presence of an emergency vehicle (EV) is disclosed. The method 320-380 comprises receiving a plurality of image frames taken by image sensors (114, 116) over a period of time, determining an EV colour component for pixels in each frame based on the ratio of a first colour (e.g. blue) relative to the total colour in each pixel and assigning to a pixel a first value if the EV colour component exceeds a threshold value and a second value if it does not. The method further comprises: determining for each of the plurality of image frames an EV colour value for the first colour based on the sum of all of the first values for each image frame; and generating a time domain representation (e.g. Fig. 4a) based on the EV colour values associated with the plurality of frames, then converting the time domain representation to a frequency spectrum (e.g. Fig. 4b), and determining if any flashing light sources of the first colour associated with emergency vehicles (e.g. police, ambulance, fire) are present by analysing the frequency spectrum.
Emergency vehicle detection
2020-06-03
Patent
Electronic Resource
English