Multi-touch sensing system optimizing touch bulbs under ambient lighting
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Solution Overview
Problem
Conventional multi-touch sensing systems face challenges in accurately detecting multiple touch points under varying ambient lighting conditions and are prone to errors due to increased costs and complexity, especially when affected by infrared noises or multiple fingers in the detection area.
Innovation Solution
A multi-touch sensing system employing an image capturing module, computing module, and processing module that captures touch images, converts them into histograms, selects a grayscale threshold through dichotomy, calculates the separability factor, and performs image binarization to accurately identify touch bulbs, allowing for operation instructions based on motion trajectories without additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of photo sensors is increased to improve the recognition rate of multiple touch points, then the detection accuracy is improved, but the system cost increases and flexibility is reduced
Solution Approach 1:
The patent merges the functions of multiple photo sensors into a single camera. The camera captures images of the touch panel, and through image processing algorithms, it identifies multiple touch points, their positions, and motion trajectories. This consolidation maintains multi-touch detection capability while significantly reducing system cost and complexity.
Solution Approach 2:
The patent replaces the mechanical/optical system of multiple photo sensors with an electronic imaging system (camera). The camera uses electronic image capture and digital processing to detect touch points, substituting the need for multiple physical photo sensors with a single electronic imaging device and software-based detection algorithms.
2Measurement precision
If multiple sensing units are used to detect photo interrupt points, then the detection capability is improved, but detection errors occur easily due to masking between fingers
Solution Approach 1:
The patent transitions from detecting photo interrupt points (one-dimensional linear detection) to capturing full two-dimensional images of the touch panel. This dimensional change allows the system to see the complete spatial arrangement of multiple fingers simultaneously, eliminating masking errors that occur when fingers block each other's light in linear sensor arrays.
Solution Approach 2:
The patent creates a visual copy (image) of the entire touch panel surface, capturing all touch points and their relative positions simultaneously. This image-based approach allows the system to analyze the complete touch scenario without the limitations of sequential or linear detection methods, where one sensor might be blocked by another finger.
3Measurement precision
If two or more cameras are used to capture information of the touch interface, then the sensing accuracy is improved, but the device complexity and cost increase
Solution Approach 1:
The patent makes a single camera perform multiple functions that would traditionally require multiple cameras or additional sensors. The camera captures touch position information, determines motion trajectories, identifies touch sequence, and provides spatial relationships between multiple touch points. This multi-functional approach achieves high sensing accuracy without increasing device complexity.
4Adaptability or versatility
If conventional touch systems are used under varying ambient lighting conditions, then the system operation is maintained, but wrong determinations occur due to infrared noises and lighting variations
Solution Approach 1:
The patent changes the detection parameter from infrared light intensity (which is affected by ambient lighting and infrared noises) to visual light reflection patterns captured by a camera. By using the camera's image sensor to detect reflected light from the touch panel surface and analyzing the resulting image patterns, the system becomes insensitive to infrared interference and ambient lighting variations, maintaining determination accuracy across different environmental conditions.
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
The system maintains stability and flexibility by automatically finding the best grayscale threshold for image segmentation, reducing computational complexity and costs, and accurately identifying touch points even under different illumination conditions or with multiple touch points, without requiring additional sensing modules or cameras.
Implementation Method 1
uses a camera to capture a light spot produced by the touch of a user's moving fingers on the touch panel
Implementation Method 2
converts the touch image into a histogram, and selects a grayscale threshold to segment the histogram by dichotomy
Implementation Method 3
a camera to capture a light spot produced by the touch of a user's moving fingers on the touch panel
Data Source
AI summary
The present invention discloses a multi-touch sensing system capable of optimizing touch bulbs according to the variation of ambient lighting conditions and a method thereof. The system comprises an image capturing module, a computing module and a processing module. The image capturing module captures a touch image. The computing module converts the touch image into a histogram and selects a grayscale threshold to segment the histogram by dichotomy for generating a segmented image of touch bulbs, and then calculates a between-class variance and a total pixel variance of the segmented image to estimate the separability factor thereof. The processing module determines whether or not the separability factor conforms to a predetermined value; if yes, then the processing module performs an image binarization of the touch image to generate a binary image, or else the processing module repeats the aforementioned process until the separability factor conforms to a predetermined value.