Capacitive Input Object Separation Using Pixel Response Functions
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Solution Overview
Problem
Current proximity sensing techniques often mistakenly identify multiple fingers as a single finger, leading to incorrect interface actions in input devices.
Innovation Solution
A processing system coupled with an input device that obtains a capacitive image of sensor pixels, determines pixel response functions, and uses a search method to distinguish and locate multiple input objects by calculating their capacitive contributions, thereby accurately identifying the locations of multiple fingers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current proximity sensing techniques are used to detect input objects, then the device can identify input objects in the sensing region, but multiple fingers are mistakenly identified as a single finger leading to incorrect interface actions
Solution Approach 1:
The patent segments the capacitive image into multiple candidate regions by identifying local maxima and creating separate candidate input objects. This segmentation allows the system to distinguish between multiple fingers that would otherwise be merged into a single detection, thereby improving measurement precision and reliability of interface actions.
Solution Approach 2:
The patent changes parameters by introducing pixel response functions and capacitive contribution calculations to differentiate between overlapping input objects. By analyzing capacitive contributions at different locations and using parameter adjustments in the search method, the system can accurately separate and identify multiple fingers, resolving the contradiction between detection capability and identification accuracy.
2Device complexity
If simple proximity sensing is used, then the device structure remains simple, but the system cannot distinguish between multiple fingers in the sensing region
Solution Approach 1:
The patent performs preliminary actions by pre-calculating pixel response functions and storing them for later use. This preliminary computation enables the system to quickly process capacitive images and distinguish multiple fingers without requiring complex real-time computation, thus maintaining relative system simplicity while improving measurement precision.
Solution Approach 2:
The patent introduces pixel response functions as an intermediary between the raw capacitive image and the final object identification. These functions act as a mediator that translates capacitive measurements into meaningful object distinctions, allowing the system to achieve high measurement precision without proportionally increasing device complexity.
3Device complexity
If traditional capacitive imaging is used, then the processing method remains simple, but multiple input objects are incorrectly merged into a single object
Solution Approach 1:
The patent implements feedback by using the capacitive image to generate candidate regions, then using pixel response functions to calculate capacitive contributions, and finally refining the identification through iterative search methods. This feedback loop ensures that information about multiple input objects is preserved and correctly separated, preventing loss of information while maintaining reasonable processing complexity.
Solution Approach 2:
The patent adds another dimension to the processing by introducing the concept of capacitive contributions as a separate analytical layer. Instead of simply detecting peaks in the capacitive image, the system analyzes capacitive contributions across different spatial dimensions using pixel response functions, enabling proper separation of multiple objects without excessive complexity.
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 enhances the accuracy of input device functionality by correctly distinguishing and locating multiple fingers, preventing incorrect interface actions and improving usability.
Implementation Method 1
A processing system coupled with an input device obtains a capacitive image of sensor pixels
Implementation Method 2
various receiver electrodes configured to obtain various resulting signals in response to transmitting the sensing signals
Data Source
AI summary
A method may include obtaining a capacitive image of various sensor pixels in an input device. The capacitive image may include various capacitive measurements resulting from the first input object and the second input object in a sensing region of the input device. The method may further include obtaining various pixel response functions corresponding to the sensor pixels. The method may further include determining, from the capacitive image and using a search method and the pixel response functions, various capacitive contributions of the first input object in the capacitive image and various capacitive contributions of the second input object. The method may further include determining, using the capacitive contributions of the first input object and the capacitive contributions of the second input object, a first location of the first input object and a second location of the second input object.