Robot Cleaner Laser Timing Control for Eye Safety and Image SNR
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Solution Overview
Problem
Robot cleaners face challenges in achieving a sufficient signal-to-noise ratio (SNR) for image acquisition while safely protecting user eye safety from high-output laser light, as increasing laser output is harmful and reducing noise requires high-quality filters, increasing manufacturing costs and complexity.
Innovation Solution
A robot cleaner with a light irradiation unit that optimizes laser output timing, using a rolling shutter method for image sensor exposure and synchronized light irradiation, ensuring that laser light is only emitted during specific exposure periods and not continuously, thereby reducing eye safety risks and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser output is increased to improve SNR, then image distinctiveness is improved, but user eye safety is compromised
Solution Approach 1:
The laser light source is controlled to emit light periodically only during the exposure period of the image sensor, rather than continuously. This timing synchronization ensures that laser light is present when needed for image capture but absent during other periods, reducing cumulative exposure and eye safety risks while maintaining sufficient signal intensity during the active exposure window to achieve good SNR and image distinctiveness
2Measurement precision
If high-quality filters are used to reduce external light noise, then SNR is improved, but manufacturing cost and process complexity increase
Solution Approach 1:
Instead of relying on complex filters to reduce noise during image capture, the system performs preliminary action by controlling the laser light source to emit only during the exact exposure period. This proactive timing control prevents external light noise from interfering with the structured light pattern in the first place, achieving high SNR through temporal separation rather than spectral filtering, thereby avoiding the need for expensive and complex filter assemblies
3Measurement precision
If laser light is emitted continuously to ensure sufficient signal, then image quality is maintained, but energy consumption increases
Solution Approach 1:
The laser light source operates in periodic pulses synchronized with the image sensor's exposure timing, emitting light only when the sensor is actively capturing images. This intermittent operation mode maintains sufficient signal intensity during exposure periods to ensure high image quality while eliminating energy consumption during non-exposure periods, significantly reducing overall laser energy usage 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 maintains a consistent SNR for image acquisition while ensuring user safety by controlling laser output timing, reducing overall energy consumption and manufacturing costs, and preventing eye damage from high-output laser light.
Implementation Method 1
a light irradiation unit configured to irradiate light towards a region in front of the main body
Implementation Method 2
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
Figure 1
Figure 2
Figure 3~4
AI summary
Disclosed herein is a robot cleaner including 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.