Control Algorithm To Trigger Camera Frame Rate Alteration For Low Light Performance Enhancement

摘要

The present invention is a combined integration of a control algorithm 3 and light sensors 2 to trigger change of frame rate in the vision systems 1, preferably processed in virtual cockpit unit 4 and displayed on integrated central stack 5 into an automobile 6. This method contributes to visual performance improvement of vision systems 1, when present in extreme low light. Performance improvements can be witnessed with increase in visibility of objects in scene. The V2X Exterior lighting 7, Ambient light sensor 8, Exterior light sensor 10 are a part of the light sensors 2 which continuously measure the external lighting condition. The GPS/HD maps 9, further predicts an external lighting condition based on jsunrise and sunset times, a combination of which compute the Exterior lighting confidence level 22. The eV value, exposure values, signal levels 15,16,17, 18 are calculated from front camera 11, right camera 12, rear camera 13, left camera 14 respectively. The standard deviation (calibratable limits) 19 is calculated from the exposure values 15, 16, 17, 18. In case standard deviation 19 is more than the limits, exterior lighting confidence 22 is verified for highlight or lowlight decision making. In case of exterior lighting confidently reports highlight/lowlight 23, front camera 11, right camera 12, rear camera 13, left camera 14 are commanded to operate at High-light frames per second 24. When standard deviation 19 is less than the limits, the black level, signal levels 15, 16,17,18 are verified for being less than a calibratable value 21. When signal levels 15,16,17,18 are less than calibratable value 21, exterior lighting confidence level 22 is considered to make a final decision and simultaneously going back to monitor signal levels 20. When signal levels 15,16, 17, 18 are less than calibratable value 21, the front camera 11, right camera 12, rear camera 13, left camera 14, are commanded to operate at Low-light frames per second 25. This algorithm is very stable and does not allow individual cameras to operate at different frame rates. The calibratable standard deviation limits 19, calibratable signal level thresholds 21 help in stabilizing the frame rate switch. By considering the light sensors 2, the cameras automatically switch to lower frame whenever necessary rather than being triggered by external conditions or electronic control units in automobile.