Capacitance Proximity Sensing Ignore Zones for Large Object Detection
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Solution Overview
Problem
Conventional capacitance proximity/touch sensing systems face challenges in accurately detecting large objects with irregular surfaces or that move, often resulting in erroneous input events due to threshold adjustments, which can either fail to detect large objects or misinterpret small objects as large objects.
Innovation Solution
The implementation of proximity sensing systems that generate 'ignore' zones around detected large objects, with these zones having a limited duration to prevent false input events, allowing for precise detection and tracking of large objects' movements and shape changes without triggering false touches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the LO detection threshold is lowered to detect irregular large objects, then detection sensitivity for large objects is improved, but small objects are misinterpreted as large objects resulting in false LO detection
Solution Approach 1:
The patent segments the detection process into multiple stages: initial threshold-based detection followed by a verification stage using a lower threshold and contiguity analysis. This segmentation allows the system to use a higher initial threshold for quick detection while using the lower threshold only for verification, thus preventing small objects from being misclassified as large objects.
Solution Approach 2:
The patent performs preliminary detection using a higher threshold before conducting the final large object determination. This preliminary action identifies candidate regions that then undergo further verification through contiguity analysis and lower threshold checking, ensuring that small objects are filtered out before final classification.
2Reliability
If the LO detection threshold is raised to prevent false detection of small objects, then false positive rate is reduced, but large objects fail to be detected
Solution Approach 1:
The patent divides the threshold application into two segments: a higher threshold for preliminary filtering and a lower threshold for final verification. This allows the system to benefit from both high and low thresholds - using the high threshold to reduce false positives and the low threshold to ensure large objects are detected, with the contiguity analysis bridging the gap between the two.
Solution Approach 2:
The patent dynamically adjusts the effective threshold based on the detection stage and object characteristics. Rather than using a static threshold, the system adapts by applying different thresholds at different stages of the detection process, allowing optimal performance across varying conditions.
3Ease of operation
If conventional LO detection is used for moving large objects, then initial detection capability is maintained, but false input events are generated when objects move beyond originally sensed region
Solution Approach 1:
The patent performs preliminary large object detection and establishes an ignore zone before subsequent touch events are processed. This preliminary action ensures that when a large object moves, the system has already prepared a protective ignore zone that prevents false input events during the movement transition.
Solution Approach 2:
The patent creates an ignore zone that extends beyond the currently detected large object boundaries, providing a cushion or buffer zone. This beforehand cushioning ensures that when the object moves, there is already a protective zone in place to prevent false detection of the moving object as a new touch event.
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 effectively prevents false input events by designating sense events within the ignore zones as invalid, ensuring accurate detection of large objects and small touches, even when objects move or change shape, thereby enhancing the reliability of touch screen interactions.
Implementation Method 1
conventional system 1500 can include an array of sensors, each of which can generate a count value corresponding to its capacitance
Data Source
AI summary
A method of sensing at least one object in proximity to an array of sensors can include making a determination that an object greater than a predetermined size has been detected; defining an ignore zone that includes sensor locations of the object and sensor locations surrounding those of the object; and removing the ignore zone after a predetermined duration; wherein the proximity of objects outside of the ignore zone are processed differently than the proximity of objects inside of the ignore zones.