Robot Cleaner Laser Timing for Rolling-Shutter Obstacle Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Robot cleaners face challenges in improving the signal-to-noise ratio (SNR) for image detection while minimizing the risk of eye damage from high-output laser light and managing manufacturing costs, particularly in reducing noise from external light sources.
Innovation Solution
The robot cleaner controls the exposure timing of its image sensor using the rolling shutter method, optimizing the output timing of laser light to ensure user safety and maintain a sufficient SNR without increasing laser light output, by synchronizing the light irradiation with the vertical synchronization signal and adjusting the exposure and irradiation periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the output of laser light is increased to improve the signal-to-noise ratio, then the distinctiveness of the pattern in the captured image is improved, but the risk of eye damage to users increases
Solution Approach 1:
The patent applies periodic action by controlling the laser light source to emit light in synchronized intervals with the rolling shutter exposure cycles. The light is turned on during specific exposure periods and off during others, creating a periodic emission pattern that ensures sufficient light intensity during measurement while limiting cumulative exposure to safe levels, thereby resolving the contradiction between measurement precision and safety.
2Measurement precision
If a high-quality filter is used to decrease noise from external light, then the signal-to-noise ratio is improved, but the manufacturing cost increases and manufacturing process management becomes more difficult
Solution Approach 1:
The patent extracts and eliminates the need for expensive high-quality optical filters by using temporal separation instead. By synchronizing laser emission with rolling shutter exposure timing, the system achieves high signal-to-noise ratio through temporal filtering (taking measurements only when laser is active) rather than spatial or spectral filtering, thereby removing the need for costly filter components and simplifying manufacturing.
3Measurement precision
If the laser light is emitted continuously to maintain sufficient signal intensity, then the signal-to-noise ratio is maintained, but the energy consumption increases and user safety is compromised
Solution Approach 1:
The system implements periodic action by pulsing the laser light source in synchronization with the rolling shutter exposure cycles. The laser emits light only during the periods when the image sensor is exposed, and remains off during other periods. This periodic emission maintains sufficient signal intensity for accurate measurement while dramatically reducing overall energy consumption compared to continuous emission.
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 reduces the overall energy consumption of laser light while ensuring user safety and maintaining a consistent SNR, allowing the robot cleaner to effectively detect obstacles without exposing users to harmful light levels.
Implementation Method 1
an image sensor including a plurality of horizontal lines sequentially exposed to form an image of the region in front of the main body
Data Source
AI summary
A robot cleaner may include a main body, a light irradiation unit irradiating light towards a region in front of the main body, an image sensor including a plurality of horizontal lines sequentially exposed to form an image, an image processing unit constructing frames by synchronizing signals output from the horizontal lines, such that, after construction of any one frame, the image processing unit does not construct one or more frames by ignoring signals output from the horizontal lines, and then constructs a next frame, and a controller controlling the light irradiation unit to irradiate light while the horizontal lines are exposed to construct the one frame, such that the light irradiation unit stops irradiation of light between before exposure of all the horizontal lines to construct the frame is completed and one point of time while the image processing unit ignores signals output from the horizontal lines.