Time-of-Flight Autofocus for Glass Detection
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Solution Overview
Problem
Conventional image capture devices struggle to accurately focus on objects behind transparent barriers or reflective surfaces, such as glass or mirrors, due to passive autofocusing techniques that often misinterpret these surfaces as the target, leading to slower focusing speeds and improper image capture.
Innovation Solution
Incorporating a time-of-flight ranging sensor that transmits optical pulse signals and processes return signals to distinguish between objects and highly reflective surfaces, generating a confidence value to adjust the autofocus system accordingly, allowing the device to focus on objects behind transparent barriers or reflective surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If passive autofocusing techniques are used to detect transparent barriers, then the device can identify glass surfaces, but the focusing speed decreases and accuracy deteriorates
Solution Approach 1:
The patent replaces passive optical autofocus mechanisms with an active time-of-flight sensing system that uses emitted light pulses to actively measure distance, enabling rapid and accurate distance detection regardless of transparent barriers
Solution Approach 2:
The patent introduces a time-of-flight sensor as an intermediary device that actively emits light and measures return time to determine distance, serving as a mediator between the camera system and the transparent barrier to enable accurate focusing
2Measurement precision
If time-of-flight sensors are used to sense distance through transparent barriers, then distance measurement is possible, but the sensor incorrectly focuses on the barrier instead of the object behind it
Solution Approach 1:
The patent uses feedback from the time-of-flight sensor to detect when a transparent barrier is present, then adjusts the autofocus system accordingly to focus on objects behind the barrier rather than the barrier itself
Solution Approach 2:
The patent dynamically adjusts the focusing behavior based on time-of-flight data, switching between different focusing modes depending on whether a transparent barrier is detected, enabling adaptive and reliable focusing in varying conditions
3Extent of automation
If the autofocusing system adjusts focus based on sensed distance to transparent surfaces, then distance-based focusing is achieved, but image capture quality deteriorates
Solution Approach 1:
The patent employs feedback from the time-of-flight sensor to detect transparent barriers and automatically adjusts the autofocus system to compensate, maintaining high image capture quality while preserving automatic focusing functionality
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
Enables reliable distance sensing and accurate focusing on objects behind transparent barriers or reflective surfaces, improving focusing speed and image capture quality by differentiating between reflective surfaces and intended targets.
Implementation Method 1
a time-of-flight ranging sensor configured to transmit optical pulse signals and to receive return optical pulse signals
Implementation Method 2
the time-of-flight ranging sensor processes the return optical pulse signals to sense distances to a plurality of objects and to generate a confidence value indicating whether one of the plurality of objects has a highly reflective surface
Data Source
AI summary
A device includes a time-of-flight ranging sensor configured to transmit optical pulse signals and to receive return optical pulse signals. The time-of-flight ranging sensor processes the return optical pulse signals to sense distances to a plurality of objects and to generate a confidence value indicating whether one of the plurality of objects has a highly reflective surface. The time-of-flight sensor generates a range estimation signal including a plurality of sensed distances and the confidence value. The image capture device includes autofocusing circuitry coupled to the time-of-flight sensor to receive the range estimation signal and configured to control focusing based upon the sensed distances responsive to the confidence value indicating none of the plurality of objects has a highly reflective surface. The autofocusing circuitry controls focusing independent of the sensed distances responsive to the confidence value indicating one of the objects has a highly reflective surface.