Vehicular Camera and IR Emitter Synchronization for Lower Power Use
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Solution Overview
Problem
Vehicle vision systems that utilize cameras and infrared (IR) LEDs for imaging face challenges in minimizing power consumption, particularly due to the high power requirements of IR LEDs, which are typically operated at the same frame rate as the camera, leading to inefficient energy use.
Innovation Solution
Synchronizing the operation of IR LEDs with the camera's imager to operate at different frame rates, where the LEDs are activated only during exposure, reducing their power usage by capturing image data when illuminated and using it for specific driving assist functions, such as night vision or object detection, while turning them off or reducing power during other functions like headlamp control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If IR LEDs are operated at the same frame rate as the camera, then image quality for driving assist functions is maintained, but power consumption increases significantly
Solution Approach 1:
The patent applies periodic action by operating IR LEDs at a different frame rate than the camera, activating them only during specific exposure periods when image data is being captured. This allows the system to maintain reliable image capture for driving assist functions while significantly reducing IR LED power consumption by keeping them off during other time periods.
2Illumination intensity
If IR LEDs are operated continuously at high power, then illumination for night vision is sufficient, but energy efficiency deteriorates
Solution Approach 1:
The system uses periodic action by pulsing IR LEDs on and off at specific intervals synchronized with camera exposure timing. During exposure periods, LEDs provide sufficient illumination intensity for night vision; during non-exposure periods, LEDs remain off to improve energy efficiency, achieving both adequate illumination and reduced energy loss.
Solution Approach 2:
The patent applies preliminary action by pre-synchronizing IR LED activation with camera exposure timing. The system prepares and activates LEDs at the precise moment before exposure begins, ensuring sufficient illumination is already present when the camera captures image data, thereby maintaining illumination intensity while avoiding continuous operation.
3Adaptability or versatility
If IR LEDs operate at camera frame rate, then all driving assist functions receive adequate illumination, but power consumption increases
Solution Approach 1:
The system applies periodic action by selectively activating IR LEDs only during camera exposure periods when image data is being captured for driving assist functions. This selective periodic operation maintains adaptability and versatility for multiple driving assist functions while significantly reducing power consumption compared to continuous operation at camera frame rate.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces IR LED power consumption by operating them at a slower rate than the camera, saving about three-quarters of power compared to simultaneous operation, while maintaining effective image capture for various driving assist functions.
Implementation Method 1
one or more infrared (IR) or near IR light emitting diodes (LEDs)
Implementation Method 2
infrared (IR) or near IR light emitting diodes (LEDs)
Data Source
AI summary
A vehicular vision system includes a camera, a near-infrared light emitter operable to illuminate at least part of a region viewed by the camera, and an electronic control unit having an image processor. The camera captures frames of image data at a first rate, and the near-infrared light emitter is pulsed on/off at a second rate. The first rate is greater than the second rate. First frames of image data are captured by the camera when the region is illuminated by light emitted by the near-infrared light emitter, and the captured first frames of image data are processed at the ECU for a first vehicle function. Second frames of image data are captured by the camera when the region is not illuminated by light emitted by the near-infrared light emitter, and the captured second frames of image data are processed at the ECU for a second vehicle function.